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  • 2015-2019
  • 1990-1994  (341)
  • 1955-1959  (7)
  • 1905-1909
  • 1890-1899
  • Agrobacterium
  • gene expression
  • 1
    Electronic Resource
    Electronic Resource
    Effect of radical scavengers on TNFα-mediated activation of the uPA in cultured cells (1994)
    Springer
    Cellular and molecular life sciences 50 (1994), S. 958-962 
    Details
    ISSN: 1420-9071
    Keywords: Plasminogen activator ; active oxygen ; gene expression ; radical scavengers ; endothelial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Active oxygen, produced by cultured cells following stimulation with various growth factors, seems to be involved in signal transduction leading to cellular responses such as gene expression and growth modulation. In the present study, the intracellular oxidation state was measured in immortalized human endothelial cells (ECV304) after treatment with tumor necrosis factor (TNF)α, using a fluorescent dye and a laser-scanning confocal microscope. The intracellular oxidation state was increased 60 min after the addition of TNFα, and this increase was abolished by a radical scavenger, N-acetylcysteine (NAC), which is also a precursor of glutathione, and by pyrrolidine dithiocarbamate (PDTC). TNFα increased the steady state level of urokinase-type plasminogen activator (uPA), and NAC inhibited this increase at a dose that also inhibited the increase in the intracellular oxidation state. PDTC, on the other hand, did not affect the induction of the uPA gene by TNFα. These results suggest that intracellular glutathione level rather than the oxidation state is necessary for the induction of the uPA gene by TNFα.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923487
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  • 2
    Electronic Resource
    Electronic Resource
    Expression of glycogen synthase and phosphofructokinase in muscle from Type 1 (insulin-dependent) diabetic patients before and after intensive insulin treatment (1994)
    Springer
    Diabetologia 37 (1994), S. 82-90 
    Details
    ISSN: 1432-0428
    Keywords: Type 1 (insulin-dependent) diabetes mellitus ; gene expression ; skeletal muscle ; glycogen synthase ; phosphofructokinase ; hexokinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to determine whether short-term appropriate insulinization of Type 1 (insulin-dependent) diabetic patients in longterm poor glycaemic control (HbA1C〉9.5%) was associated with an adaptive regulation of the activity and gene expression of key proteins in muscle glycogen storage and glycolysis: glycogen synthase and phosphofructokinase, respectively. In nine diabetic patients biopsies of quadriceps muscle were taken before and 24-h after intensified insulin therapy and compared to findings in eight control subjects. Subcutaneous injections of rapid acting insulin were given at 3-h intervals to improve glycaemic control in diabetic patients (fasting plasma glucose decreased from 20.8±0.8 to 8.7±0.8 mmol/l whereas fasting serum insulin increased from 59±8 to 173±3 pmol/l). Before intensified insulin therapy, analysis of muscle biopsies from diabetic patients showed a normal total glycogen synthase ctivity but a 48% decrease (p=0.006) in glycogen synthase fractional velocity (0.1 mmol/l glucose 6-phosphate) (FV0.1) and a 45% increase (p=0.01) in the half-maximal activation constant of glycogen synthase (A0.5). The activity of phosphofructokinase and the specific mRNA and immunoreactive protein levels of both glycogen synthase and phosphofructokinase were similar in the two groups. The 2.8-fold increase in serum insulin levels and the halving of the plasma glucose level for at least 15 h were associated with a normalization of glycogen synthase fractional activity (FV0.1) and of the half-maximal activation constant (A0.5) whereas the enzyme activity of phosphofructokinase and the mRNA and protein levels of both glycogen synthase and phosphofructokinase remained normal. In conclusion: 1) Reduced allosterical activation of glycogen synthase in muscle of Type 1 diabetic patients in poor metabolic control occurs in the presence of normal total activity as well as normal immunoreactive protein mass and mRNA level of glycogen synthase. 2) Changes in serum insulin within the physiological range play no role in the short-term regulation of glycogen synthase mRNA and protein abundance in muscle from Type 1 diabetic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428782
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  • 3
    Electronic Resource
    Electronic Resource
    Tissue-specific correction of lipogenic enzyme gene expression in diabetic rats given vanadate (1994)
    Springer
    Diabetologia 37 (1994), S. 1065-1072 
    Details
    ISSN: 1432-0428
    Keywords: Key words Vanadium ; lipogenic enzymes ; gene expression ; streptozotocin-diabetic rats.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Vanadium is a potent insulinomimetic agent. In vivo, its blood glucose lowering action in insulin-deficient diabetic rats is associated with corrected expression of genes involved in hepatic glucose metabolism. In this study, we investigated whether vanadate treatment also reverses the impaired expression of genes coding for key enzymes of lipogenesis in diabetic liver and white adipose tissue. Oral administration of vanadate to streptozotocin-rats caused a 55 % fall in plasma glucose levels after feeding without modifying low insulinaemia. It also partially corrected the low thyroid hormone concentrations. In untreated diabetic animals, hepatic mRNA levels of acetyl-CoA carboxylase and fatty acid synthase were reduced by more than 80 and 90 %, respectively, in close correlation with changes in enzyme activities. Three weeks of vanadate treatment totally restored acetyl-CoA carboxylase mRNA and partially restored fatty acid synthase mRNA (71 % of control levels). The activities of both lipogenic enzymes were increased 3.5 to 4-fold, to reach 45 to 65 % of control values. By contrast, in white adipose tissue, vanadate modified neither expression nor activity of both lipogenic enzymes, which remained blunted (〈 10 % of control levels). In conclusion, vanadate treatment partially restores the activities of two key lipogenic enzymes in liver, but not in white adipose tissue, of diabetic rats. This correction results from a reversal of impaired pre-translational regulatory mechanisms possibly mediated by an improvement of thyroid function and a selective restoration of liver glycolytic flux. [Diabetologia (1994) 37: 1065–1072]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418369
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  • 4
    Electronic Resource
    Electronic Resource
    Pancreatic Reg/pancreatic stone protein (PSP) gene expression does not correlate with beta-cell growth and regeneration in rats (1994)
    Springer
    Diabetologia 37 (1994), S. 994-999 
    Details
    ISSN: 1432-0428
    Keywords: Pancreas ; growth factors ; gene expression ; beta cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Reg/pancreatic stone protein (PSP) gene is postulated to be an important regulator of pancreatic beta-cell growth. To investigate this hypothesis, we analysed the expression of the Reg/PSP gene following a 90% pancreatectomy and after chronic glucose infusion, two well-defined models of pancreatic beta-cell growth. There was a rapid induction of the Reg/PSP gene in the remnant pancreas after a 90% pancreatectomy in rats during the period of marked growth of the exocrine and islet tissue. However, a similar rapid, but smaller, induction of the Reg/PSP gene was observed in sham-operated rats and in non-surgical control rats in which there was no enhanced pancreatic growth. Furthermore, there was no pancreatic Reg/PSP gene induction in a model of selective beta-cell growth, the chronic glucose-infused rat. Thus, it is unlikely that Reg/PSP is a beta-cell specific growth factor, even though the function of this important pancreatic gene is still unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400462
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  • 5
    Electronic Resource
    Electronic Resource
    Pancreatic Reg/pancreatic stone protein (PSP) gene expression does not correlate with beta-cell growth and regeneration in rats (1994)
    Springer
    Diabetologia 37 (1994), S. 994-999 
    Details
    ISSN: 1432-0428
    Keywords: Key words Pancreas ; growth factors ; gene expression ; beta cells.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Reg/pancreatic stone protein (PSP) gene is postulated to be an important regulator of pancreatic beta-cell growth. To investigate this hypothesis, we analysed the expression of the Reg/PSP gene following a 90 % pancreatectomy and after chronic glucose infusion, two well-defined models of pancreatic beta-cell growth. There was a rapid induction of the Reg/PSP gene in the remnant pancreas after a 90 % pancreatectomy in rats during the period of marked growth of the exocrine and islet tissue. However, a similar rapid, but smaller, induction of the Reg/PSP gene was observed in sham-operated rats and in non-surgical control rats in which there was no enhanced pancreatic growth. Furthermore, there was no pancreatic Reg/PSP gene induction in a model of selective beta-cell growth, the chronic glucose-infused rat. Thus, it is unlikely that Reg/PSP is a beta-cell specific growth factor, even though the function of this important pancreatic gene is still unknown. [Diabetologia (1994) 37: 994–999]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400462
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  • 6
    Electronic Resource
    Electronic Resource
    Tissue-specific correction of lipogenic enzyme gene expression in diabetic rats given vanadate (1994)
    Springer
    Diabetologia 37 (1994), S. 1065-1072 
    Details
    ISSN: 1432-0428
    Keywords: Vanadium ; lipogenic enzymes ; gene expression ; streptozotocin-diabetic rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Vanadium is a potent insulinomimetic agent. In vivo, its blood glucose lowering action in insulin-deficient diabetic rats is associated with corrected expression of genes involved in hepatic glucose metabolism. In this study, we investigated whether vanadate treatment also reverses the impaired expression of genes coding for key enzymes of lipogenesis in diabetic liver and white adipose tissue. Oral administration of vanadate to streptozotocin-rats caused a 55% fall in plasma glucose levels after feeding without modifying low insulinaemia. It also partially corrected the low thyroid hormone concentrations. In untreated diabetic animals, hepatic mRNA levels of acetyl-CoA carboxylase and fatty acid synthase were reduced by more than 80 and 90%, respectively, in close correlation with changes in enzyme activities. Three weeks of vanadate treatment totally restored acetyl-CoA carboxylase mRNA and partially restored fatty acid synthase mRNA (71% of control levels). The activities of both lipogenic enzymes were increased 3.5 to 4-fold, to reach 45 to 65% of control values. By contrast, in white adipose tissue, vanadate modified neither expression nor activity of both lipogenic enzymes, which remained blunted (〈10% of control levels). In conclusion, vanadate treatment partially restores the activities of two key lipogenic enzymes in liver, but not in white adipose tissue, of diabetic rats. This correction results from a reversal of impaired pre-translational regulatory mechanisms possibly mediated by an improvement of thyroid function and a selective restoration of liver glycolytic flux.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418369
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  • 7
    Electronic Resource
    Electronic Resource
    A reporter gene under the control of tms or aux promoters is differentially expressed in tobacco and barley protoplasts (1994)
    Springer
    Plant cell reports 13 (1994), S. 155-158 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium ; auxin biosynthesis genes ; barley and tobacco protoplasts ; transient expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Agrobacterium tumefaciens and some Agrobacterium rhizogenes strains possess auxin biosynthesis genes (tms and aux genes respectively), responsible for a de novo auxin biosynthetic pathway in transformed plant cells. A comparison is presented of the potential expression of these genes in a monocotyledonous (barley) and a dicotyledonous plant (tobacco). The promoters of the genes were translationally fused to the β-glucuronidase reporter gene and analysed in transient expression experiments. The tms and aux fusions were highly expressed in tobacco, but not in barley. However, the aux enhancer active in tobacco, conferred low β-glucuronidase expression in barley when fused to a truncated cauliflower mosaic virus 35S promoter. The results are discussed in relation to the differential responses to Agrobacterium infection in monocots and dicots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239883
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  • 8
    Electronic Resource
    Electronic Resource
    Stable expression of the GUS reporter gene in chrysanthemum depends on binary plasmid T-DNA (1994)
    Springer
    Plant cell reports 14 (1994), S. 59-64 
    Details
    ISSN: 1432-203X
    Keywords: Agrobacterium ; transformation ; T-DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three chrysanthemum (Dendranthema grandiflora) cultivars were cocultivated with 2 Agrobacterium tumefaciens strains in combination with 4 pBIN19 derived binary plasmids, all carrying the Nosnptll selection gene and 35Sgus(intron) reporter gene. All binary plasmids transferred DNA to chrysanthemum explants but only pMOG410 gave good stable expression of GUS. This plasmid differs from the other plasmids in 2 aspects: 1) It carries a restored nptll gene and 2) the selection gene is positioned at the left border side of the reporter gene. Cocultivation with AGLO(pMOG410) yielded up to 13 GUS positive shoots per 100 explants. The presence of the gus and nptll gene in recovered shoots was confirmed by PCR and Southern blot analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233300
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  • 9
    Electronic Resource
    Electronic Resource
    Agrobacterium-mediated transformation of commercial melon (Cucumis melo L., cv. Amarillo Oro) (1994)
    Springer
    Plant cell reports 13 (1994), S. 145-148 
    Details
    ISSN: 1432-203X
    Keywords: muskmelon ; gene transfer ; Agrobacterium ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cotyledon explants of muskmelon (Cucumis melo L., cv. Amarillo Oro) seedlings were co-cultivated with disarmed Agrobacterium tumefaciens strain LBA4404 that contained the binary vector plasmid pBI121.1. The T-DNA region of this binary vector contains the Nopaline synthase/neomycin phosphotransferase II (NPTII) chimeric gene for kanamycin resistance and the Cauliflower Mosaic Virus 35S/β-glucuronidase (GUS) chimeric gene. After infection, the cotyledon pieces were placed in induction medium containing 100 mg/l kanamycin. Putative transformed shoots were obtained, followed by the development of morphologically normal plantlets. The transgenic nature of regenerants was demonstrated by polymerase chain reaction, Southern blot analysis, plant growth on medium selective for the transgene (NPTII) and expression of the co-transformed GUS gene. Factors affecting the transformation procedure are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239881
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of plant genotype on the transformation of cultivated alfalfa (Medicago sativa) by Agrobacterium tumefaciens (1994)
    Springer
    Plant cell reports 13 (1994), S. 330-334 
    Details
    ISSN: 1432-203X
    Keywords: Medicago sativa ; Alfalfa ; Transformation ; Agrobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The trait for somatic embryogenesis is being introduced sexually into alfalfa (Medicago sativa) breeding populations to facilitate genetic transformation of this crop. Cocultivation experiments were conducted with an agronomically-improved embryogenic clone from one such population as well as with two other embryogenic clones, one of which was the source of the embryogenic trait in the breeding populations. Transgenic plants were produced from the agronomically-improved clone whereas none were produced from the other two clones. Among the 16 transgenic plants analyzed there was a range in both copy number and number of integration sites for the NPT-II gene; those plants regenerated after a prolonged selection phase in vitro generally had the highest numbers in both respects. There was no evidence of sectoral chimerism of the transgene in a subsample of transgenic plants analyzed by PCR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232631
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  • 11
    Electronic Resource
    Electronic Resource
    Identification of Agrobacterium strains by PCR-RFLP analysis of pTi and chromosomal regions (1994)
    Springer
    Archives of microbiology 161 (1994), S. 300-309 
    Details
    ISSN: 1432-072X
    Keywords: Agrobacterium ; 16S rDNA ; 16S rDNA-23S rDNA Intergenic spacer ; tmr Gene ; nos Gene ; virA Gene ; virB2 Gene ; Polymerase chain reaction ; Restriction fragment length polymorphism ; Crown gall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosomes and Ti plasmids of 41 Agrobacterium strains, belonging to biovars 1, 2, 3, and Agrobacterium rubi species were characterized by the restriction fragment length polymorphism of PCR-amplified DNAs. Profiles that were obtained by the analysis of the amplified 16S rDNA confirmed the grouping of the strains according to their species. Higher polymorphism was detected in the intergenic spacer between the 16S rDNA and 23S rDNA genes, allowing efficient discrimination of strains. Identification of most strains was possible, and the genetic relatednesses of Agrobacterium strains could be estimated. The analysis of the plasmid Ti encoded regions between the tmr and nos genes, and the virA and virB2 genes, allowed fingerprinting of Ti plasmids. Genomic typing by the rapid PCR-RFLP method is thus shown to be useful for an independant identification of strains and of the conjugative Ti plasmids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303584
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  • 12
    Electronic Resource
    Electronic Resource
    Several phenotypic changes in the cell envelope of Agrobacterium tumefaciens chvB mutants are prevented by calcium limitation (1994)
    Springer
    Archives of microbiology 161 (1994), S. 310-315 
    Details
    ISSN: 1432-072X
    Keywords: Agrobacterium ; β-1,2-Glucan ; chvB Mutants—Ca2+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chvB gene of Agrobacterium tumefaciens encodes a 235 kDa proteinaceous intermediate involved in the synthesis of β-1,2-glucan. chvB mutants show a pleiotropic phenotype. Besides not to produce cyclic β-1,2-glucan, chvB mutants have been reported to be avirulent, attachment-deficient, and nonmotile. In this study we report additional differences from the parent strain, probably all linked to changes in the cell envelope. This pleiotropic phenotype — except for attachment and virulence — could largely be prevented by growing chvB cells with low levels of calcium. Although a role for β-1,2-glucan in osmoadaptation has been proposed, the mode of action of β-1,2-glucan is not known. We speculate that in A. tumefaciens β-1,2-glucan stabilizes membranes, which would be important especially in hypotonic media containing calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303585
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  • 13
    Electronic Resource
    Electronic Resource
    Expression of calcium-binding protein regucalcin mRNA in rat liver is stimulated by calcitonin: The hormonal effect is mediated through calcium (1994)
    Springer
    Molecular and cellular biochemistry 136 (1994), S. 43-48 
    Details
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The involvement of a hypocalcemic hormone calcitonin (CT) in the expression of hepatic Ca2+-binding protein regucalcin mRNA was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). A single oral administration of calcium chloride (100 mg Ca/100 g body weight) to rats induced a remarkable increase in the serum calcium concentration and a corresponding elevation of the liver calcium content during 120 min after the administration. Thyroparathyroidectomy (TPTX) did not cause a significant increase in the liver calcium content after calcium administration. Hepatic regucalcin mRNA level was markedly elevated by calcium administration; the level was about 180% of controls at 60 min after the administration. This increase was completely abolished by TPTX. A single subcutaneous administration of CT (synthetic eel CT; 25–100 MRC mU/100 g) to TPTX rats received oral administration of calcium (100 mg/100 g) produced a remarkable increase in hepatic regucalcin mRNA levels; the level was about 280% of controls with the dose of 25 MRC mU CT/100 g. The present finding suggests that the expression of hepatic mRNA is stimulated by CT, and that the hormonal effect is mediated through Ca2+ in rat liver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00931603
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  • 14
    Electronic Resource
    Electronic Resource
    Expression of hepatic calcium-binding protein regucalcin mRNA is decreased by phenobarbital administration in rats (1994)
    Springer
    Molecular and cellular biochemistry 141 (1994), S. 15-19 
    Details
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; phenobarbital ; rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of phenobarbital on the expression of calcium-binding protein regucalcin mRNA in rat liver was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin cDNA (0.9 kb of open reading frame). Phenobarbital (4, 8 and 12 mg/ 100 g body weight) was intraperitoneally administered to rats 3 times with 24 h intervals, and the animals were sacrificed by bleeding at 24 h after the last administration. The hepatic regucalcin mRNA levels were markedly reduced by phenobarbital administration. This decrease was about 50% of control level with the 12 mg/100 g dose. Moreover, the hepatic regucalcin concentration was significantly decreased by the administration of phenobarbital (12 mg/100 g), although the serum regucalcin concentration was not altered appreciably. Meanwhile, serum transaminases (GOT and GPT) activities were not increased by the administration of phenobarbital (4 and 12 mg/100 g). The present study demonstrates that the expression of hepatic regucalcin mRNA is decreased by phenobarbital administration in rats, suggesting that regucalcin does not have a role in drug metabolism related to phenobarbital.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00935586
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  • 15
    Electronic Resource
    Electronic Resource
    Regulation of mRNA transcripts and DNA synthesis in the rat heart following intravenous injection of transforming growth factor beta1 (1994)
    Springer
    Molecular and cellular biochemistry 141 (1994), S. 145-151 
    Details
    ISSN: 1573-4919
    Keywords: pressure overload ; myocardium ; gene expression ; fibroblast ; extracellular matrix ; ventricular hypertrophy ; growth factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Transforming Growth Factor-beta1 (TGF-β1) is expressed in the heart by muscle and non-muscle cardiac cells.In vitro, cardiac myocytes and non-muscle cells including cardiac fibroblasts and endothelial cells respond to regulatory effects of TGF-β1. Expression of TGF-β1 in the heart is subject to regulation by hemodynamic stimuli. Increased expression of mRNA transcripts for TGF-β1 has been reported in several models of cardiac hypertrophy. The objective of this study was to determine the effect of TGF-β1 in the myocardium. TGF-β1 was injected intravenously. Expression of mRNA transcripts for functional and structural proteins was determined by Northern hybridization analysis. DNA synthesis was determined by measurement of3H-thymidine incorporation into ventricular DNA. The results showed differential regulation of mRNAs for myocyte- and non-myocyte-specific proteins in the heart of TGF-β1 treated rats. Moderate but statistically significant decrease in DNA synthesis was observed in the heart of TGF-β1 treated rats (37.5%, P〈0.025). Together, these data point to a physiological role for TGF-β1 in the heart. They further suggest that similar to its diversein vitro cell-specific regulatory effects, TGF-β1 may have multicellular targets in the heart. Effect of TGF-β1 alone or combined with those of other cytokines/hormones that come into play, as the result of its administration, may be responsible for altered gene expression and DNA synthesis in the myocardium. We propose that in experimental models of myocardial hypertrophy which are associated with increased expression of TGF-β1 in the heart, the contribution of regulatory effects of this growth factor to the manifestations of ventricular hypertrophy could be significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00926178
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  • 16
    Electronic Resource
    Electronic Resource
    Calcium and calcium-binding proteins in the nucleus (1994)
    Springer
    Molecular and cellular biochemistry 135 (1994), S. 79-88 
    Details
    ISSN: 1573-4919
    Keywords: calcium ; nucleus ; calpain ; calmodulin ; cell division ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Calcium has long been known to play a role as a key cytoplasmic second messenger, but until relatively recently its possible involvement in nuclear signal transduction and the regulation of nuclear events has not been extensively studied. Evidence revealing the presence of transmembrane nuclear Ca2+ gradients and a variety of intranuclear Ca2+ binding proteins has fueled renewed interest in this key ion and its involvement in cell-cycle timing and division, gene expression, and protein activation. This review will offer an overview of the current state of knowledge and theory regarding calcium orchestration of nuclear functions and events and discuss possible future directions in this field of study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00925963
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  • 17
    Electronic Resource
    Electronic Resource
    Transcriptional regulation and autoregulation of the human gene for ADP-ribosyltransferase (1994)
    Springer
    Molecular and cellular biochemistry 138 (1994), S. 99-104 
    Details
    ISSN: 1573-4919
    Keywords: poly(ADP-ribosyl) transferase (human) ; autoregulation ; gene expression ; promoter structure ; cruciform structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Human nuclear poly(ADP-ribosyl)transferase (ADPRT) modifies proteins with branched ADP-ribose-polymers. Various proteins, including ADPRT itself, serve as acceptors for polyADP-ribose. Target proteins include those controlling basic cellular processes such as DNA repair, differentiation and proliferation. Because of the outstanding features of this enzyme: automodification, several functional domains and central role in physiology of the cell, the molecular biology of ADPRT gained wide interest. The promoter structure contains several CCAAT/TATA boxes and SP1 sites. However, there is no CCAAT/TATA box in the neighbourhood of an SP1 site and, thus no obvious site for initiation of transcription. Within this region there are several noteworthy inverted repeats, which by internal basepairing could form two types of cruciform structures. Deletion analysis revealed that these cruciform structures have functional significance. Removal of one type increases the promoter activity, whereas removal of the other diminishes the promoter function. Overexpression of ADPRT from heterologous promoters (MMTV, SV40) leads to repression of the activity of the ADPRT promoter. Indeed, ADPRT was shown to bind specifically to one type of cruciform structure. This specific interaction indicates autorepression of the ADPRT gene: the enzyme ADPRT acts directly as a negative modulator of the activity of its own promoter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00928449
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  • 18
    Electronic Resource
    Electronic Resource
    Expression of the mitochondrial creatine kinase genes (1994)
    Springer
    Molecular and cellular biochemistry 133-134 (1994), S. 235-243 
    Details
    ISSN: 1573-4919
    Keywords: creatine kinase ; mitochondria ; metabolism ; creatine phosphate shuttle ; gene expression ; muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Mitochondrial Creatine Kinase (MtCK) is responsible for the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine, and exists in mammals as two isoenzymes encoded by separate genes. In rats and humans, sarcomere-specific MtCK (sMtCK) is expressed only in skeletal and heart muscle, and has 87% nucleotide identity across the 1257 bp coding region. The ubiquitous isoenzyme of MtCK (uMtCK) is expressed in many tissues with highest levels in brain, gut, and kidney, and has 92% nucleotide identity between the 1254 bp coding regions of rat and human. Both genes are highly regulated developmentally in a tissue-specific manner. There is virtually no expression of sMtCK mRNA prior to birth. Unlike cytosolic muscle CK (MCK) and brain CK (BCK), there is no developmental isoenzyme switch between the MtCKs. Cell culture models representing the tissue-specific expression of either sMtCK or uMtCK are available, but there are no adequate developmental models to examine their regulation. Several animal models are available to examine the coordinate regulation of the CK gene family and include 1) Cardiac Stress by coarctation (sMtCK, BCK, and MCK), 2) Uterus and placenta during pregnancy (uMtCK and BCK), and 3) Diabetes and mitochondrial myopathy (sMtCK, BCK, and MCK). We report the details of these findings, and discuss the coordinate regulation of the genes necessary for high-energy transduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01267957
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  • 19
    Electronic Resource
    Electronic Resource
    Nuclear Ca2+: physiological regulation and role in apoptosis (1994)
    Springer
    Molecular and cellular biochemistry 135 (1994), S. 89-98 
    Details
    ISSN: 1573-4919
    Keywords: calcium ; cell death ; nuclei ; apoptosis ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The last decade has seen the rapid development of research investigating the molecular mechanisms whereby hormones, peptide growth factors and cytokines regulate cell metabolism, differentiation and proliferation. One general signalling mechanism used to transfer the information delivered by agonists into appropriate intracellular compartments involves the rapid Ca2+ redistribution throughout the cell, which results in transient elevations of the cytosolic free Ca2+ concentration. Ca2+ signals are required for a number of cellular processes including the activation of nuclear processes such as gene transcription and cell cycle events. The latter require that appropriate Ca2+ signals elicited in response to agonists be transduced across the nuclear envelope. It has generally been assumed that small molecules, metabolites and ions could freely diffuse across the nuclear envelope. Nevertheless several findings during the past few years have suggested that nuclear pore permeability can be regulated and that ion transport systems and ion-selective channels may exist on the nuclear membranes and regulate intranuclear processes. Intranuclear Ca2+ fluctuations can affect chromatin organization, induce gene expression and also activate cleavage of nuclear DNA by nucleases during programmed cell death or apoptosis. The possible mechanisms involved in nuclear Ca2+ transport and the control of nuclear Ca2+-dependent enzymes in apoptosis is discussed below.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00925964
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  • 20
    Electronic Resource
    Electronic Resource
    A retinoic acid-inducible skin-specific gene (RIS-1/psoriasin): molecular cloning and analysis of gene expression in human skinin vivo and cultured skin cellsin vitro (1994)
    Springer
    Molecular biology reports 20 (1994), S. 75-83 
    Details
    ISSN: 1573-4978
    Keywords: retinoic acid ; skin ; differential hybridization ; cloning ; keratinocytes ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A retinoic acid (RA) inducible skin-specific gene transcript (RIS-1) was isolated by differential hybridization screening of a RA-treated human skin cDNA library. The library was constructed from pooled RNA derived from normal adult human skin treated with alltrans-RA for 4 h (n=6) and 12 h (n=6)in vivo. RIS-1 cDNA corresponded to a 0.6 kb transcript that was barely detectable in normal adult human skin but was significantly induced by 8 h in RA-treated compared to vehicle-treated skin (range 1.1–3.6 fold). Prolonged RA treatment for up to 24 h further increased relative RIS-1 mRNA levels by 1.3–5.5 fold. HPLC analysis of the RA content of 0.1% RA-treated skinin vivo revealed significant levels at 6 h (18.8–120.6 ng RA/g wet weight tissue; approximately 240 nM), immediately preceding the time point at which the increased RIS-1 mRNA level was first seen. This concentration of RA also induced the mRNA levels for cellular RA binding protein II (1.6–19 fold), a marker of RA activity in human skin. RIS-1 mRNA was detected by Northern and dot blotting only in normal skin but not in any other normal human tissues examined, indicating a tissue-specific pattern of gene expression. RIS-1 transcripts were detected at very low levels in untreated cultured human epidermal keratinocytes, while no expression was seen in dermal fibroblasts and melanocytes, the other major cell types in skin. Southern analysis of human and mouse DNA indicated the existence of evolutionarily conserved sequences for RIS-1 between these two species. The polypeptide sequence derived from the partial RIS-1 cDNA was found to be identical to the calcium binding domain found in ‘psoriasin’, a gene whose expression appears to be increased in the skin of psoriasis patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00996356
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  • 21
    Electronic Resource
    Electronic Resource
    Expression of nitrate assimilation related genes in Chlamydomonas reinhardtii (1994)
    Springer
    Plant molecular biology 24 (1994), S. 185-194 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; light/nitrate regulation ; nitrate reductase ; nitrate transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mRNA accumulation pattern of the Chlamydomonas reinhardtii nitrate assimilation-related gene cluster has been elucidated. In ammonium-grown wild-type cells, nit-1 (nitrate reductase, NR), nar-1, nar-2 and nar-3 (nitrate transporter) genes showed very similar kinetics of expression when transferred to nitrate medium. Transcripts of all these genes accumulated transiently in ammonium-grown wild-type cells after a one-hour incubation in nitrogen-free medium, and practically disappeared at about 2 hours. Mutant strains lacking functional nitrate reductase showed similar accumulation kinetics of these transcripts during both nitrate induction and derepression in nitrogen-free media. In contrast to the other nar transcripts, that nar-4, a gene sharing similar sequences with nar-3, accumulated in small amounts in wild-type cells, and only increased after a long nitrate induction period. Nitrate and light showed a strong positive effect on the accumulation of nit-1 gene transcripts. Acetate as a carbon source allowed accumulation of nit-1 mRNA in the dark, indicating the existence of interactions between light and carbon metabolism in nit-1 gene expression. Our data strongly suggest that NR negatively autoregulates its own expression and that of nar genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040584
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  • 22
    Electronic Resource
    Electronic Resource
    Expression of one of the members of the Arabidopsis chaperonin 60β gene family is developmentally regulated and wound-repressible (1994)
    Springer
    Plant molecular biology 24 (1994), S. 195-202 
    Details
    ISSN: 1573-5028
    Keywords: plant transformation ; chaperonin 60β ; β-glucuronidase ; wound repression ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To study the pattern of gene regulation of the plastid chaperonin 60β gene family a chimaeric gene was constructed fusing the 5′-flanking region of the chaperonin 60β B3 gene to the β-glucuronidase reporter gene. Histochemical and fluorometric analysis of the GUS activity present in transgenic plants harbouring this gene construct showed that the B3 promoter is expressed in leaves, stem, petioles and several flower tissues. The pattern of cell type-specific expression in stems and flowers was found to be developmentally regulated. Expression of the B3 promoter was found not to be heat-inducible, but highly repressed by wounding. The rapid decay in GUS activity upon wounding indicates that, at least under some physiological conditions, the gene product of this reporter gene is not as stable as has been previously thought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040585
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  • 23
    Electronic Resource
    Electronic Resource
    Low-temperature-responsive barley genes have different control mechanisms (1994)
    Springer
    Plant molecular biology 24 (1994), S. 879-888 
    Details
    ISSN: 1573-5028
    Keywords: barley ; cold acclimation ; gene expression ; low temperature genes ; nuclear run-on transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several low-temperature-responsive (LTR) genes from barley have been shown to have high steady-state transcript levels. Run-on transcription was used to determine the control of expression of these LTR genes. Six of these are shown to be transcriptionally regulated (blt 4/9, blt 101, blt 1015, blt 63, blt 49, blt 410) whilst three are post-transcriptionally regulated (blt 14, blt 411, blt 801). Two transcriptionally regulated genes (blt 4/9 and blt 101) and one post-transcriptionally regulated gene (blt 14) have been used in expression studies. The time course for the appearance and decay of these transcripts is given. Initial appearance and steady-state levels of individual transcripts have different temperature characteristics but no single gene correlates with the cold acclimation response. We suggest that these different response profiles may represent a means of fine-tuning the low-temperature response. One gene, blt 4/9, also accumulated high steady-state levels of transcript in response to drought and a nutrient stress. However, only drought has an acclimating effect on barley plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014442
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  • 24
    Electronic Resource
    Electronic Resource
    The 24kDa outer envelope membrane protein from spinach chloroplasts: molecular cloning, in vivo expression and import pathway of a protein with unusual properties (1994)
    Springer
    Plant molecular biology 25 (1994), S. 167-177 
    Details
    ISSN: 1573-5028
    Keywords: Spinacia oleracea ; chemical cleavage ; gene expression ; polymerase chain reaction ; protein transport ; SDS-PAGE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 24 kDa outer envelope membrane protein of spinach chloroplasts (omp24) represents a major constituent of this membrane. Sequences of tryptic and endoprotease Glu-C peptides derived from omp24 allowed the design of oligonucleotides which were used to generate a DNA fragment by polymerase chain reaction using spinach cDNA as template. This fragment served as a probe to screen a cDNA library for a full-length clone of the omp24 coding sequence. The protein predicted from the complete sequence only has 148 amino acids and a molecular mass of 16294 Da. It is an acidic protein (calculated isoelectric point 4.8) with a high content of proline residues. Expression of the coding sequence in Escherichia coli and characterization of the purified recombinant protein produced revealed that the overestimation of its molecular mass by SDS-PAGE (ca. 25 kDa) is due to its abnormal amino acid composition. Despite its rather low hydrophobicity (polarity index 49%), omp24 appears to be deeply embedded in the outer membrane. Insertion of omp24 into the membrane proceeds almost independently of surface receptors or targeting sequence but, in contrast to other known outer envelope membrane proteins, is stimulated by ATP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023235
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  • 25
    Electronic Resource
    Electronic Resource
    Gene expression of nitrite reductase in Scots pine (Pinus sylvestris L.) as affected by light and nitrate (1994)
    Springer
    Plant molecular biology 25 (1994), S. 449-457 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; light ; nitrate ; nitrite reductase ; Pimus sylvestris L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A partial cDNA clone (PSnir) encoding the C-terminal region of nitrite reductase was isolated from a λgt 11 library of the gymnospermPimus sylvestris (L.). Nucleotide sequence analysis showed that PSnir contains a reading frame encoding 105 amino acid residues. The amino acid sequence revealed a homology to NiR of 63–68% to dicotyledoneous and of 57–59% to monocotyledoneous species. The protein region implicated to be involved in binding of the prosthetic group is highly conserved between the NiR of the gymnosperm and of angiosperms. In all organs (cotyledonary whorls, hypocotyls, roots) the pattern of NiR gene expression in response to nitrate and light is the same at the level of transcript accumulation and at the enzyme level. This suggests that regulation of NiR gene expression in the Scots pine seedling is predominantly at the level of transcript accumulation. The highest NiR appearance was observed in roots and hypocotyls. In the cotyledonary whorls only small amounts of NiR were found. In roots and hypocotyls the accumulation of NiR mRNA and the appearance of NiR protein is mainly controlled by nitrate, whereas the regulation of NiR gene expression in the whorls is strongly affected by light and the inducive effect of nitrate is only weak.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043873
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  • 26
    Electronic Resource
    Electronic Resource
    Isolation and characterization of two tightly linked catalase genes from castor bean that are differentially regulated (1994)
    Springer
    Plant molecular biology 25 (1994), S. 507-516 
    Details
    ISSN: 1573-5028
    Keywords: castor bean (Ricinus communis) ; catalase gene ; gene expression ; germination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two catalase genes,cat1 andcat2, have been isolated from the castor bean genome. They were located in the same direction on a chromosome at a distance of 2.4 kb,cat1 being on the downstream side ofcat2. The two genes contained introns at the same positions except that one of the 7 introns incat1 is missing incat2 and the corresponding introns differed in size and sequence between the two genes. The translated regions of the two genes had the same number of nucleotides and exhibited 81.3% nucleotide sequence identity. In addition to introns, the nucleotide sequences of the 5′-and 3′-flanking regions are highly divergent between the two genes. In etiolated seedlings,cat1 mRNA was present abundantly in endosperms and cotyledons and only in a small amount in roots. Thecat1 mRNA could not be detected in hypocotyls. By contrast,cat2 mRNA is most abundant in hypocotyls and roots, while endosperms and cotyledons contained only low levels ofcat2 mRNA. Although neithercat1 norcat2 mRNA could be detected in dry seeds, both mRNAs showed temporal accumulation in the endosperm in response to germination. These results suggest that expression of two tightly linked catalase genes of castor bean,cat1 andcat2, are differentially regulated during development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043878
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  • 27
    Electronic Resource
    Electronic Resource
    Localization of the VirA domain involved in acetosyringone-mediatedvir gene induction inAgrobacterium tumefaciens (1994)
    Springer
    Plant molecular biology 25 (1994), S. 899-907 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; gene regulation ; sensor protein ; signal transduction ; VirA protein ; acetosyringone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The VirA protein ofAgrobacterium tumefaciens is thought to be a receptor for plant phenolic compounds such as acetosyringone. Although it is not known whether the interaction between VirA and the phenolics is direct or requires other phenolic-binding proteins, it is shown in this study that the first 280 amino acids of the VirA protein are not essential for the acetosyringone mediatedvir gene induction response. Considering the fact that the cytoplasmic region between the amino acids 283 and 304 is highly conserved between the different VirA proteins, and that deletion of this region abolishes VirA activity, we suggest that the acetosyringone receptor domain is located in this cytoplasmic domain of the VirA protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028884
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  • 28
    Electronic Resource
    Electronic Resource
    The small, versatilepPZP family ofAgrobacterium binary vectors for plant transformation (1994)
    Springer
    Plant molecular biology 25 (1994), S. 989-994 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; binary vectors ; gentamycin resistance ; kanamycin resistance ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The newpPZP Agrobacterium binary vectors are versatile, relatively small, stable and are fully sequenced. The vectors utilize the pTiT37 T-DNA border regions, the pBR322bom site for mobilization fromEscherichia coli toAgrobacterium, and the ColE1 and pVS1 plasmid origins for replication inE. coli and inAgrobacterium, respectively. Bacterial marker genes in the vectors confer resistance to chloramphenicol (pPZP100 series) or spectinomycin (pPZP200 series), allowing their use inAgrobacterium strains with different drug resistance markers. Plant marker genes in the binary vectors confer resistance to kanamycin or to gentamycin, and are adjacent to the left border (LB) of the transferred region. A lacZ α-peptide, with the pUC18 multiple cloning site (MCS), lies between the plant marker gene and the right border (RB). Since the RB is transferred first, drug resistance is obtained only if the passenger gene is present in the transgenic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014672
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  • 29
    Electronic Resource
    Electronic Resource
    Purification and partial characterization of a glycoprotein from pea (Pisum sativum) with receptor activity for rhicadhesin, an attachment protein of Rhizobiaceae (1994)
    Springer
    Plant molecular biology 24 (1994), S. 171-183 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; attachment ; plant receptor ; rhicadhesin ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Attachment of Rhizobium and Agrobacterium bacteria to cells of their host plants is a two-step process. The first step, direct attachment of bacteria to the plant cell wall, is mediated by the bacterial protein rhicadhesin. A putative plant receptor molecule for rhicadhesin was purified from cell walls of pea roots using a bioassay based on suppression of rhicadhesin activity. This molecule appeared to be sensitive to treatments with pronase or glycosidase. Its isoelectric point is 6.4, and its apparent molecular mass was estimated to be 32 kDa before and 29 kDa after glycosidase treatment, as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and ultrafiltration. The sequence of the first 29 N-terminal amino acids was determined: A-D-A-D-A-L-Q-D-L-C(?)-V-A-D-Y-A-S-V-I-L-V-N-G-F-A-S-K(Q)-(P/Q)-(L)-(I). No homology with known proteins was found. In the course of this research project the extracellular matrix protein vitronectin was reported to inhibit attachment of A. tumefaciens to carrot cells [29]. A variety of adhesive proteins, including vitronectin, contain a common cell attachment determinant with the sequence R-G-D. Since we could not detect other cell wall components able to suppress rhicadhesin activity, and since an R-G-D containing hexapeptide was also active as a receptor, we speculate that the plant receptor for rhicadhesin is a glycoprotein containing an R-G-D attachment site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040583
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  • 30
    Electronic Resource
    Electronic Resource
    Characterization of four new β-tubulin genes and their expression during male flower development in maize (Zea mays L.) (1994)
    Springer
    Plant molecular biology 24 (1994), S. 295-315 
    Details
    ISSN: 1573-5028
    Keywords: β-tubulin ; microtubules ; maize ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four different β-tubulin coding sequences were isolated from a cDNA library prepared from RNA from maize seedling shoots. The four genes (designated tub4, tub6, tub7 and tub8) represented by these cDNA clones together with the tub1 and tub2 genes reported previously encode six β-tubulin isotypes with 90–97.5% amino acid sequence identity. Results from phylogenetic analysis of 17 β-tubulin genes from monocot and dicot plant species indicated that multiple extant lines of β-tubulin genes diverged from a single precursor after the appearance of the two major subfamilies of α-tubulin genes described previously. Hybridization probes from the 3′ non-coding regions of six β-tubulin clones were used to quantify the levels of corresponding tubulin transcripts in different maize tissues including developing anthers and pollen. The results from these dot blot hybridization experiments showed that all of the β-tubulin genes were expressed in most tissues examined, although each gene showed a unique pattern of differential transcript accumulation. The tub1 gene showed a high level of transcript accumulation in meristematic tissues and almost no accumulation in the late stages of anther development and in pollen. In contrast, the level of tub4 transcripts was very low during early stages of male flower development but increased markedly (more than 100 times) during the development of anthers and in pollen. Results from RNAse protection assays showed that this increased hybridization signal resulted from expression of transcripts from one or two genes closely related to tub4. The tub4-related transcripts were not present in shoot tissue. Transcripts from the tub2 gene accumulated to very low levels in all tissues examined, but reached the highest levels in young anthers containing microspore mother cells. RNAse protection assays were used to measure the absolute levels of α- and β-tubulin transcripts in seedling shoot and in pollen. The α-tubulin gene subfamily I genes (tua1, tua2, tua4) contributed the great majority of α-tubulin transcripts in both shoot and pollen. Transcripts from the β-tubulin genes tub4, tub6, tub7, and tub8 were predominant in shoot, but were much less significant than the tub4-related transcripts in pollen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020169
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  • 31
    Electronic Resource
    Electronic Resource
    Structural and functional analysis of an Opaque-2-related gene from sorghum (1994)
    Springer
    Plant molecular biology 24 (1994), S. 515-523 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; b-ZIP motif ; seed storage proteins ; trans-acting factors ; transcription factors ; transcriptional regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Opaque-2 (O2) gene from maize encodes a transcriptional activator of the b-ZIP class. We have isolated and characterized a gene from sorghum, related in sequence to the O2 gene from maize. A single copy of the gene is present in sorghum. Both genomic and cDNA sequences of the O2-related sorghum gene were determined. The sequence is highly homologous to maize O2 both in the promoter and in the coding region. The most closely related sequences contain the b-ZIP domain with only 11 amino acid substitutions in a total of 122 residues. In transient expression assays, the sorghum O2-related coding sequence, expressed from a CaMV 35S promoter, activates expression from the maize b-32 promoter as effectively as that obtained with the maize O2 sequence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024119
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  • 32
    Electronic Resource
    Electronic Resource
    Cloning of two gibberellin-regulated cDNAs from Arabidopsis thaliana by subtractive hybridization: expression of the tonoplast water channel, γ-TIP, is increased by GA3 (1994)
    Springer
    Plant molecular biology 24 (1994), S. 603-615 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; dwarf mutant ; gene expression ; gibberellin ; subtractive hybridization ; tonoplast intrinsic protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Arabidopsis ga1 mutant has very low levels of endogenous, active gibberellins and thus has an extreme dwarf phenotype; application of GA3 induces stem elongation and flower development. To test the hypothesis that GA action in this system involves changes in gene expression, we have cloned mRNAs whose abundance changes following GA application. A subtraction cloning scheme for the isolation of differentially regulated cDNAs was established, involving hybridization of single-stranded cDNA to biotinylated mRNA. cDNA populations enriched up to 150-fold in GA-regulated sequences were produced and cDNA libraries generated. Screening of these libraries has isolated two clones that identify mRNAs of ca. 1100 and 750 bases whose abundance is markedly increased 24 h after GA application. One of these clones encodes the vegetative form of the Arabidopsis tonoplast intrinsic protein (γ-TIP), a water channel protein, the expression of which has recently been shown to be correlated with regions of cell expansion. The second clone is expressed only in the inflorescence and encodes a proline- and glycine-rich protein that may be a cell wall component.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023557
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  • 33
    Electronic Resource
    Electronic Resource
    A phenylalanine ammonia-lyase gene from melon fruit: cDNA cloning, sequence and expression in response to development and wounding (1994)
    Springer
    Plant molecular biology 26 (1994), S. 473-479 
    Details
    ISSN: 1573-5028
    Keywords: Cucumis melo ; melon ; phenylalanine ammonia-lyase ; gene expression ; ripening ; wounding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phenylalanine ammonia-lyase (PAL) is the first enzyme of phenylpropanoid biosynthesis involved in the synthesis of a multiplicity of plant natural products. We have isolated and characterized a nearly fulllength cDNA clone (pmPAL-1) corresponding to a melon fruit (Cucumis melo L. var. reticulatus) gene coding for a protein which is highly similar to PAL from other lants. Melon fruit PAL is transcriptionally induced both in response to fruit ripening and wounding. PAL gene expression follows the kinetics of expression of the ethylene biosynthetic genes during fruit development. In contrast, ethylene biosynthetic genes show different induction kinetics compared to PAL expression in response to wounding. Similar results have been found for two other genes coding for enzymes involved in flavonoid biosynthesis (chalcone synthase, CHS; chalcone isomerase, CHI). Our results imply that regulation of defense gene expression in melon is a co-ordinated process in response to both ethylene and an ethylene-independent wound signal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039557
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  • 34
    Electronic Resource
    Electronic Resource
    Regulation of an Arabidopsis oleosin gene promoter in transgenic Brassica napus (1994)
    Springer
    Plant molecular biology 25 (1994), S. 193-205 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis ; embryo ; gene expression ; oleosin ; promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Progressive deletions of the 5′-flanking sequences of an Arabidopsis oleosin gene were fused to β-glucuronidase (GUS) and introduced into Brassica napus plants using Agrobacterium-mediated transformation. The effect of these deletions on the quantitative level of gene expression, organ specificity and developmental regulation was assessed. In addition, the influence of abscisic acid (ABA), jasmonic acid (JA), sorbitol and a combined ABA/sorbitol treatment on gene expression was investigated. Sequences that positively regulate quantitative levels of gene expression are present between −1100 to −600 and −400 to −200 of the promoter. In addition, sequences present between −600 and −400 down-regulate quantitative levels of expression. In transgenic B. napus plants, the oleosin promoter directs seed-specific expression of GUS which is present at early stages of seed development and increases throughout seed maturation. Sequences present between −2500 and −1100 of the promoter are involved in modulating the levels of expression at early stages of embryo development. Histochemical staining of embryos demonstrated that expression is uniform throughout the tissues of the embryo. Sequences involved in the response to ABA and sorbitol are present between −400 and −200. The induction of GUS activity by a combined ABA/sorbitol treatment is additive suggesting that ABA is not the sole mediator of osmotically induced oleosin gene expression. A response to JA was only observed when the oleosin promoter was truncated to −600 suggesting that the reported effect of JA on oleosin gene expression may be at a post-transcriptional level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023237
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  • 35
    Electronic Resource
    Electronic Resource
    Characterization of a cDNA from Arabidopsis thaliana encoding a potential thiol protease whose expression is induced independently by wilting and abscisic acid (1994)
    Springer
    Plant molecular biology 25 (1994), S. 259-270 
    Details
    ISSN: 1573-5028
    Keywords: abscisic acid ; Arabidopsis thaliana ; gene expression ; mutants ; signal transduction ; stress ; thiol protease ; wilting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sequence and expression characteristics are described of a wilt-inducible gene in Arabidopsis thaliana. A 1494 encodes a potential thiol protease whose mRNA accumulates rapidly in shoot tissue upon the loss of turgor. A1494 mRNA levels peaked after ca. 4 h and declined thereafter. Dehydration also induced rapid biosynthesis of the phytohormone abscisic acid (ABA), which continued for at least 9 h. Exogenous ABA induced the accumulation of A1494 mRNA, with kinetics similar to those after wilting. Rehydration of wilted shoots led to a rapid decline in the content of both ABA and A1494 mRNA. Wilting and ABA independently induced A1494 expression as evidenced by the effects of ABA and wilting on the ABA-deficient aba-1 and ABA-insensitive abi-1 and abi-3 genotypes. A1494 mRNA was not detectable in aba-1 shoots but accumulated rapidly after either wilting or ABA treatment, whereas the shoot ABA content was increased only by ABA treatment. ABA had no effect on A1494 mRNA levels in the abi-1 and abi-3 mutants but wilting did result in enhanced A1494 expression. Heat shock had only a minor effect on A1494 mRNA levels, whereas exposure to low temperature resulted in substantial accumulation of A1494 mRNA in wild-type shoots. However, this latter response, unlike that to drought, was mediated exclusively via ABA synthesis as demonstrated by the lack of A1494 mRNA accumulation in cold-treated aba-1 shoots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023242
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  • 36
    Electronic Resource
    Electronic Resource
    Tissue-specific expression of the large ATP synthase gene cluster in spinach plastids (1994)
    Springer
    Plant molecular biology 25 (1994), S. 369-376 
    Details
    ISSN: 1573-5028
    Keywords: ATP synthase ; chloroplast ; gene expression ; plastid ; RNA stability ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plastids present in different tissues may vary morphologically and functionally, despite the fact that all plastids within the same plant contain identical genomes. This is achieved by regulation of expression of the plastid genome by tissue-specific factors, the mechanisms of which are not fully understood. The proton translocating ATP synthase/ATPase is a multisubunit complex composed of nine subunits, six encoded in the plastid and three in the nucleus. We have investigated the tissue-specific expression of the large ATP synthase gene cluster in spinach (Spinacia oleracea). This gene cluster encodes four of the six plastid-encoded ATP synthase genes. Transcript abundance, transcriptional activity, and transcript stability were investigated relative to gene dosage in root plastids and in stem, leaf, and flower chloroplasts. All three of these factors display significant tissue-specific variation. It was intriguing to discover that, although transcript abundance normalized to gene dosage varies in each tissue, transcript abundance as a proportion of the entire plastid RNA population in each tissue is not significantly different. Thus it appears that in these tissues the variation in transcription and stability of transcripts derived from the large ATP synthase gene cluster balances to yield an equivalent proportion of these transcripts in the plastid RNA population. Expression of this gene cluster in photosynthetic as well as non-photosynthetic tissues may facilitate the plasticity of structure and function which is characteristic of plastids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043866
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  • 37
    Electronic Resource
    Electronic Resource
    The Chlorella virus adenine methyltransferase gene promoter is a strong promoter in plants (1994)
    Springer
    Plant molecular biology 26 (1994), S. 85-93 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; monocot cells ; promoter strength ; transient expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An upstream region isolated from a eukaryotic algal virus adenine methyltransferase gene was tested for promoter function in plants. Fusion of this region to the chloramphenicol acetyltransferase reporter gene resulted in significantly higher expression than fusion with the cauliflower mosaic virus 35S promoter. Strong levels of expression were also found in electroporated monocot plant cells. The promoter activity in transgenic tobacco plants showed tissue-specific expression. Leaves had the highest expression followed by stems and flowers. The promoter activity was not detected in root tissue. Environmental cues, such as light, and the phytohormones auxin and cytokinines had no effect on the promoter's expression. This promoter might be utilized to achieve high levels of expression of introduced genes in higher plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039522
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  • 38
    Electronic Resource
    Electronic Resource
    Meristem-specific gene expression directed by the promoter of the S-phase-specific gene, cyc07, in transgenic Arabidopsis (1994)
    Springer
    Plant molecular biology 24 (1994), S. 863-878 
    Details
    ISSN: 1573-5028
    Keywords: cell cycle ; gene expression ; meristem ; promoter analysis ; transgenic Arabidopsis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A genomic clone for the cyc07 gene, which is expressed specifically at the S phase during the cell cycle in synchronous cultures of periwinkle (Catharanthus roseus) cells, was isolated. Determination of the nucleotide sequence of the clone revealed that the cyc07 gene consists of seven exons separated by six introns. Genomic Southern analysis indicated that the cyc07 gene is present as a single copy per haploid genome in periwinkle. Expression of related genes was detected in a wide range of other plants. Transgenic Arabidopsis plants were generated that expressed the gene for β-glucuronidase (GUS) under the control of the promoter of the cyc07 gene. The tissue-specific pattern of expression directed by the promoter was investigated by analysis of GUS activity. Histochemical tests demonstrated that 589 bp of the 5′-upstream sequence of the cyc07 gene could direct specifical expression of the GUS reporter gene in meristematic tissues in transgenic plants. The spatial pattern of expression directed by the promoter was closely correlated with meristematic activity and cell proliferation, suggesting an association between the function of the cyc07 gene and cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014441
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  • 39
    Electronic Resource
    Electronic Resource
    Over-production of the D1 protein of photosystem II reaction centre in the cyanobacterium Synechococcus sp. PCC 7942 (1994)
    Springer
    Plant molecular biology 26 (1994), S. 709-721 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; photosynthesis ; protein turnover ; psbA ; tac promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The unicellular cyanobacterium Synechococcus sp. PCC 7942 has three psbA genes encoding two different forms of the photosystem II reaction centre protein D1 (D1:1 and D1:2). The level of expression of these psbA genes and the synthesis of D1:1 and D1:2 are strongly regulated under varying light conditions. In order to better understand the regulatory mechanisms underlying these processes, we have constructed a strain of Synechococcus sp. PCC 7942 capable of over-producing psbA mRNA and D1 protein. In this study, we describe the over-expression of D1:1 using a tac-hybrid promoter in front of the psbAI gene in combination with lacI Q repressor system. Over-production of D1:1 was induced by growing cells for 12 h at 50 μmol photons m-2 s-1 in the presence of 40 or 80 μg/ml IPTG. The amount of psbAI mRNA and that of D1:1 protein in cells grown with IPTG was three times and two times higher, respectively. A higher concentration of IPTG (i.e., 150 μg/ml) did not further increase the production of the psbAI message or D1:1. The over-production of D1:1 caused a decrease in the level of D1:2 synthesised, resulting in most PSII reaction centres containing D1:1. However, the over-production of D1:1 had no effect on the pigment composition (chlorophyll a or phycocyanin/number of cells) or the light-saturated rate of photosynthesis. This and the fact that the total amounts of D1 and D2 proteins were not affected by IPTG suggest that the number of PSII centres within the membranes remained unchanged. From these results, we conclude that expression of psbAI can be regulated by using the tac promoter and lacI Q system. However, the accumulation of D1:1 protein into the membrane is regulated by the number of PSII centres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013756
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  • 40
    Electronic Resource
    Electronic Resource
    Environmental stress-mediated differential 3′ end formation of chloroplast RNA-binding protein transcripts (1994)
    Springer
    Plant molecular biology 26 (1994), S. 833-849 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; RNA stability regulation ; chloroplast RNA-binding protein (cRBP) ; environmental stress ; Mesembryanthemum crystallinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the characterization of transcripts from the halophyte, Mesembryanthemum crystallinum, encoding a protein with high homology to chloroplast RNA-binding proteins (cRBP). In this plant chloroplast-related functions are largely protected against salt stress. cRBP transcripts are derived from a single gene, Mc32crbp, although three size classes of polyadenylated mRNAs are detected. Transcription rate and steady state amounts of mRNA are developmentally regulated and light controlled with strong transcriptional activity as functional chloroplasts are established, and with lower maintenance activity thereafter. Upon salt stress, the rate of transcription decreases, although transcript levels increase. Accompanying stress, a change in the distribution of transcript size classes is observed as the longest transcript with an untranslated 3′ end of 381 nucleotides increases relative to transcripts with shorter 3′ ends. The long transcript is characterized by the presence of five sequence elements in the 3′-untranslated region that are present in cRBP mRNAs from a variety of plants, although not all elements are found in each mRNA. The results may indicate a mechanism by which mRNA levels of constitutively light-regulated genes may be modulated without enhanced transcription in response to environmental cues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028852
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  • 41
    Electronic Resource
    Electronic Resource
    Expression of engineered antibodies in plant cells (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1023-1030 
    Details
    ISSN: 1573-5028
    Keywords: immunoglobulin genes ; gene expression ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040685
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  • 42
    Electronic Resource
    Electronic Resource
    A method for examining expression of homologous genes in plant polyploids (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1065-1071 
    Details
    ISSN: 1573-5028
    Keywords: Brassica ; polyploid ; gene expression ; RT-PCR ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One of the essential issues regarding evolution of polyploid species is how duplicate genes are expressed. Most studies on gene expression in polyploids have been based on isozyme analyses; RNA analysis has not been widely used partially due to difficulties in distinguishing homologous transcripts which usually have the same length and similar or almost identical sequences. In this study, a method combining RT-PCR with RFLP was used to analyze transcripts of homologous genes in natural and synthetic Brassica amphidiploids. Sequences coding for several known genes were selected and used to synthesize gene-specific primers. Total RNAs were used as templates for RT-PCR to amplify homologous transcripts in three diploid parental species, three cultivated amphidiploid species and six synthetic amphidiploids. For each gene, initial PCR products amplified in all species had identical length; however, homologous transcripts in the diploid and amphidiploid species could be distinguished after digesting the PCR products with restriction enzymes. Preliminary results based on three genes indicated that both transcripts from the diploid parents were expressed in the synthetic and natural amphidiploids. This study represents the first application of RT-PCR and RFLP analysis to investigate expression of homologous genes in higher plants. The technique is a sensitive, simple and efficient method for distinguishing homologous transcripts in a mixed RNA population and can be applied to many types of studies on expression of homologous genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040689
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  • 43
    Electronic Resource
    Electronic Resource
    Molecular cloning of the Arabidopsis thaliana sedoheptulose-1,7-biphosphatase gene and expression studies in wheat and Arabidopsis thaliana (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1191-1200 
    Details
    ISSN: 1573-5028
    Keywords: Calvin cycle genes ; gene expression ; SBPase ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report here the isolation and nucleotide sequence of genomic clones encoding the chloroplast enzyme sedoheptulose-1,7-bisphosphatase (SBPase) from Arabidopsis thaliana. The coding region of this gene contains eight exons (72–76 bp) and seven introns (75–91 bp) and encodes a polypeptide of 393 amino acids. Unusually, the 5′ non-coding region contains two additional AUG codons upstream of the translation initiation codon. A comparison of the deduced Arabidopsis and wheat SBPase polypeptide sequences reveals 78.6%, identity. Expression studies showed that the level of SBPase mRNA in Arabidopsis and wheat is regulated in a light-dependent manner and is also influenced by the developmental stage of the leaf. Although the Arabidopsis SBPase gene is present in a single copy, two hybridizing transcripts were detected in some tissues, suggesting the presence of alternate transcription start sites in the upstream region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040699
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  • 44
    Electronic Resource
    Electronic Resource
    Expression of the tobacco Tnt1 retrotransposon promoter in heterologous species (1994)
    Springer
    Plant molecular biology 26 (1994), S. 393-402 
    Details
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; Brassica napus ; gene expression ; Nicotiana tabacum ; retrotransposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of the tobacco (Nicotiana tabacum) retrotransposon Tntl has previously been shown to be strongly regulated and driven from the 5′ long terminal repeat (LTR). We report here that the Tntl LTR can promote activity of the β-glucuronidase (GUS) reporter gene in two heterologous species of the Brassicaceae family, namely rapessed (Brassica napus) and Arabidopsis thaliana. The translational LTR-GUS fusion was active in transient expression studies performed with tobacco and rapeseed protoplasts, indicating that the LTR sequences are recognized in heterologous species. Our results also showed that Tntl LTR-promoted GUS expression in transgenic Arabidopsis is strongly regulated, and that, in contrast to tobacco, hormonal activation plays a significant role in the expression of the Tntl LTR in Arabidopsis. LTR sequences were shown to be more effective than the CaMV 35S enhancer region in transient expression studies performed with tobacco or rapessed protoplasts; and substitution of the LTR sequences upstream from the major transcriptional start with the CaMV 35S enhancer region gave high levels of expression in transgenic tobacco and Arabidopsis leaves, suggesting that a Tntl element with similar substitutions in its 5′ LTR might be suited for gene-tagging experiments in heterologous species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039548
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  • 45
    Electronic Resource
    Electronic Resource
    Structure and promoter analysis of an ABA- and stress-regulated barley gene, HVA1 (1994)
    Springer
    Plant molecular biology 26 (1994), S. 617-630 
    Details
    ISSN: 1573-5028
    Keywords: ABA ; barley ; gene expression ; Hordeum vulgare ; phylogeny ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A single-copy barley gene, HVA1, encoding a class 3 late embryogenesis-abundant protein, can be induced by either treatment with abscisic acid (ABA) or by stress conditions such as drought, cold, heat and salinity. We have isolated an HVA1 genomic clone containing about 400 bp of 5′-upstream sequence, a single 109 bp intron, and the full coding sequence. Linker scan mutagenesis and transient expression studies were used to test the function of four HVA1 promoter elements conserved in ABA-responsive genes. Mutations in two of these elements, the C box and the putative ABRE 1 (ABA-responsive element) containing an ACGT core, resulted in no significant change in transcription level or ABA induction. In contrast, mutations of the other two elements, putative ABRE 2 & 3 cause the level of transcription to drop to 10–20% of that obtained with the wild-type promoter indicating that the high level of expression of HVA1 is dependent on both pABRE 2 & 3. Interestingly, despite their low level of expression, the mutated promoters still gave more than 20-fold induction in response to ABA treatment. We suggest that the ABA induction of barley HVA1 gene is governed by a complex consisting of pABRE 2 & 3 working together to regulate the absolute level of expression, and either of these elements or a possible third element may regulate ABA inducibility. Phylogenetic analysis by parsimony indicates that the barley HVA1 and wheat pMA2005 sequences share a recent common ancester. These two genes are closely related to the carrot Dc3 and cotton D-7 genes with which they share a similar structural gene organization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013748
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  • 46
    Electronic Resource
    Electronic Resource
    Detection of immunologically related Kunitz and Bowman-Birk proteinase inhibitors expressed during potato tuber development (1994)
    Springer
    Plant molecular biology 26 (1994), S. 961-969 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; Kunitz-type proteinase inhibitor ; potato (Solanum tuberosum, L.) ; soybean C-II inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antiserum against a potato Kunitz-type proteinase inhibitor (PKPI) expressed in Escherichia coli was produced. In immunoblotting assays of proteins from potato tubers cultured in vitro, three proteins reacted to the antiserum, two of 20 kDa and one of 10 kDa. Their N-termini were sequenced. While the 20 kDa proteins showed 59 and 90% identity to PKPI, the 10 kDa one had 65% identity to soybean C-II proteinase inhibitor. Characterization of the temporal expression of these proteins showed that both could be detected from 10 days after induction of tuberization (DAI) in vitro, but the times when maximum amounts of PKPI and 10 kDa protein could be detected were different, corresponding to 22 and 32 DAI, respectively. The amounts of these proteins decreased in the following stages, and no positive reaction of the antiserum with mature tuber proteins could be found. The 20 kDa proteins were also detected in early stages of development of potato tubers grown in the field, indicating that these proteins are expressed during normal tuber development, and differ from the PKPIs reported previously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028862
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  • 47
    Electronic Resource
    Electronic Resource
    Cloning and molecular analysis of structural genes involved in flavonoid and stilbene biosynthesis in grape (Vitis vinifera L.) (1994)
    Springer
    Plant molecular biology 24 (1994), S. 743-755 
    Details
    ISSN: 1573-5028
    Keywords: anthocyanins ; cDNA cloning ; flavonoids ; gene expression ; genomic organization ; stilbenes ; Vitis vinifera L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genes involved in flavonoid and stilbene biosynthesis were isolated from grape (Vitis vinifera L.). Clones coding for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydoxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX) and UDP glucose:flavonoid 3-O-glucosyl transferase (UFGT), were isolated by screening a cDNA library, obtained from mRNA from seedlings grown in light for 48 h using snapdragon (Antirrhinum majus) and maize heterologous probes. A cDNA clone coding for stilbene synthase (StSy) was isolated by probing the library with a specific oligonucleotide. These clones were sequenced and when the putative products were compared to the published amino acid sequence for corresponding enzymes, the percentages of similarity ranged from 65% (UFGT) to 90% (CHS and PAL). The analysis of the genomic organization and expression of these genes in response to light shows that PAL and StSy genes belong to large multigene families, while the others are present in one to four copies per haploid genome. The steady-state level of mRNAs encoded by the flavonoid biosynthetic genes as determined in young seedlings is coordinately induced by light, except for PAL and StSy, which appear to be constitutively expressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029856
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  • 48
    Electronic Resource
    Electronic Resource
    Triticum aestivum puroindolines, two basic cystine-rich seed proteins: cDNA sequence analysis and developmental gene expression (1994)
    Springer
    Plant molecular biology 25 (1994), S. 43-57 
    Details
    ISSN: 1573-5028
    Keywords: cDNA sequence ; cystine-rich proteins ; gene expression ; puroindolines ; tryptophan-rich domain ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From a mid-maturation seed cDNA library we have isolated cDNA clones encoding two Triticum aestivum puroindolines. Puroindoline-a and puroindoline-b, which are 55% similar, are basic, cystine-rich and tryptophan-rich proteins. Puroindolines are synthezised as preproproteins which include N- and C-terminal propeptides which could be involved in their vacuolar localization. The mature proteins have a molecular mass of 13 kDa and a calculated isoelectric point greater than 10. A notable feature of the primary structure of puroindolines is the presence of a tryptophan-rich domain which also contains basic residues. A similar tryptophan-rich domain was found within an oat seed protein and a mammalian antimicrobial peptide. The ten cysteine residues of puroindolines are organized in a cysteine skeleton which shows similarity to the cysteine skeleton of other wheat seed cystine-rich proteins. Northern blot analysis showed that puroindoline genes are specifically expressed in T. aestivum developing seeds. No puroindoline transcripts as well as no related genes were detected in Triticum durum. The identity of puroindolines to wheat starch-granule associated proteins is discussed as well as the potential role of puroindolines in the plant defence mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024197
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  • 49
    Electronic Resource
    Electronic Resource
    Structure of genes that encode isozymes of aspartate aminotransferase in Panicum miliaceum L., a C4 plant (1994)
    Springer
    Plant molecular biology 26 (1994), S. 723-734 
    Details
    ISSN: 1573-5028
    Keywords: aspartate aminotransferase ; C4 photosynthesis ; gene expression ; gene structure ; isozyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cytosolic and mitochondrial isozymes of aspartate aminotransferase (AspAT) function in the C4 photosynthetic cycle in NAD-malic enzyme-type C4 plants and are expressed at high levels in mesophyll cells and bundle sheath cells, respectively. We constructed a genomic library from Panicum miliaceum, a NAD-malic enzyme-type C4 plant, and cloned the genes for these isozymes. The sequence of the cloned gene for cytosolic AspAT spans 7800 bp and consists of 12 exons. The sequence of the cloned gene for mitochondrial AspAT spans 9000 bp and consists of 10 exons. The results of primer-extension analysis suggest that transcription may be initiated from multiple adjacent sites. Both genes have significant GC-rich regions around the site of initiation of transcription, and these regions showed no CpG suppression. The 5′-flanking regions of both genes include several short sequences similar to the regulatory elements found in other genes for components of the photosynthetic machinery. In particular, the cytosolic AspAT gene contains sequences similar to nuclear protein-binding sites in other mesophyll-expressed C4 photosynthetic genes and the mitochondrial AspAT gene contains elements for light-sensitive and constitutive expression of a bundle sheath-expressed gene. The results of Southern analysis indicated that there are at least two genes that encode each isozyme in the genome of P. miliaceum. A comparison of nitron-insertion positions between AspAT genes of plants and animals revealed that several introns are located at identical positions. On the basis of a phylogenetic tree among AspATs and tyrosine aminotransferase, we have shown that the introns of aminotransferase genes antedate the divergence of eubacteria, archaebacteria, and eukaryotes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013757
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  • 50
    Electronic Resource
    Electronic Resource
    Vascular expression of the grp1.8 promoter is controlled by three specific regulatory elements and one unspecific activating sequence (1994)
    Springer
    Plant molecular biology 26 (1994), S. 747-756 
    Details
    ISSN: 1573-5028
    Keywords: activating sequence ; gene expression ; glycine-rich protein ; tobacco ; vascular expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The bean grp1.8 full-length promoter is specifically active in vascular tissue during normal development of tobacco. Deletion of a negative regulatory element resulted in ectopic activity of the promoter in cortical cells of hypocotyls, roots and stems. A 169 bp fragment (−205 to −36) of the grp1.8 promoter conferred vascular-specific expression to CaMV 35S minimal promoters whereas a 141 bp fragment (−205 to −64) strongly activated these minimal promoters both in vascular and cortical cells. These experiments defined a new regulatory element (VSE) that is essential for vascular-specific expression and is located between −64 and −36. The 141 bp grp1.8 promoter sequence had enhancer-like properties as it was active in both orientations. A 24 bp sequence (bp −119 to −96, corresponding to the SE1 regulatory element) enhanced expression from several minimal promoters strongly but unspecifically, whereas a 26 bp sequence (−98 to −73, corresponding to the RSE regulatory element) induced vascular-specific expression. Thus, the grp1.8 promoter is regulated by a combinatorial mechanism that can integrate the action of different, non-additively acting regulatory elements into vascular-specific expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013759
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  • 51
    Electronic Resource
    Electronic Resource
    A dehydrin cognate protein from pea (Pisum sativum L.) with an atypical pattern of expression (1994)
    Springer
    Plant molecular biology 26 (1994), S. 805-816 
    Details
    ISSN: 1573-5028
    Keywords: Dehydrin ; gene expression ; pea (Pisum sativum L.) ; cognate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dehydrins are a family of proteins characterised by conserved amino acid motifs, and induced in plants by dehydration or treatment with ABA. An antiserum was raised against a synthetic oligopeptide based on the most highly conserved dehydrin amino acid motif, the lysine-rich block (core sequence KIKEK-LPG). This antiserum detected a novel M r 40 000 polypeptide and enabled isolation of a corresponding cDNA clone, pPsB61 (B61). The deduced amino acid sequence contained two lysine-rich blocks, however the remainder of the sequence differed markedly from other pea dehydrins. Surprisingly, the sequence contained a stretch of serine residues, a characteristic common to dehydrins from many plant species but which is missing in pea dehydrin. The expression patterns of B61 mRNA and polypeptide were distinctively different from those of the pea dehydrins during seed development, germination and in young seedlings exposed to dehydration stress or treated with ABA. In particular, dehydration stress led to slightly reduced levels of B61 RNA, and ABA application to young seedlings had no marked effect on its abundance. The M r 40 000 polypeptide is thus related to pea dehydrin by the presence of the most highly conserved amino acid sequence motifs, but lacks the characteristic expression pattern of dehydrin. By analogy with heat shock cognate proteins we refer to this protein as a dehydrin cognate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028850
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  • 52
    Electronic Resource
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    Gibberellins: perception, transduction and responses (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1529-1555 
    Details
    ISSN: 1573-5028
    Keywords: gibberellin ; growth ; development ; perception ; receptor ; gene expression ; signal transduction ; response mutant ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016489
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  • 53
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    Isolation and characterization of two β-tubulin cDNA clones from rice (1994)
    Springer
    Plant molecular biology 26 (1994), S. 1975-1979 
    Details
    ISSN: 1573-5028
    Keywords: β-tubulin ; cDNA ; rice ; monocot ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two cDNA clones encoding two different β-tubulins, RTUB-1 and RTUB-2, were isolated from a rice cDNA library and their nucleotide sequences were analyzed. The deduced amino acid sequences showed amino acid sequence identity between 92% and 97% with other plant β-tubulins. Southern blot analysis using gene-specific and coding-region probes suggested that β-tubulins in rice are encoded by multigene families. The two cDNA clones represent two subfamilies of rice tubulins. RTUB-1 and RTUB-2, consisting of 3 to 4 genes and a single gene, respectively. The transcript levels of RTUB-1 and RTUB-2 genes were higher in actively elongating tissues such as etiolated shoot tissues and light-grown root tissues of four-day old seedlings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019507
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    A simple and efficient gene transfer system of trifoliate orange (Poncirus trifoliata Raf.) (1994)
    Springer
    Plant cell reports 13 (1994), S. 541-545 
    Details
    ISSN: 1432-203X
    Keywords: Trifoliate orange ; Epicotyl segment ; Agrobacterium ; Transformation ; rolC promoter ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A simple and efficient gene transfer system of trifoliate orange (Poncirus trifoliata Raf.) was developed using epicotyl segments. The segments were infected with Agrobacterium harboring the binary vector pBI121 or pBI101-O12-p1. Both vectors contained the neomycin phosphotransferase II (NPTII) and the β-glucuronidase (GUS) genes. In the plasmid pBI101-O12-p1, the GUS gene was directed to the promoter region of ORF12 (rolC) of the Ri plasmid. On a selection medium containing 100 or 200 μg/ml kanamycin, adventitious shoots were formed from 21.7–44.6% of the segments. Histochemical GUS assay showed that 55.4–87.7% of the shoots expressed the GUS gene. The stable integration of this gene was also confirmed by polymerase chain reaction (PCR) analysis and by Southern blot analysis. When the pBI101-O12-p1 plasmid was used, the GUS activity was found to be located in phloem cells of leaf, stem and root. More than 100 transformed plants were obtained using this method within 2–3 months.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234507
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  • 55
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    Electronic Resource
    Changes in polypeptide patterns in tobacco roots colonized by two Glomus species (1994)
    Springer
    Mycorrhiza 4 (1994), S. 215-221 
    Details
    ISSN: 1432-1890
    Keywords: Nicotiana ; Glomus species ; arbuscular mycorrhiza ; gene expression ; specific polypeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in gene expression were studied during the establishment of arbuscular mycorrhizal symbiosis in tobacco roots from an amphidiploid hybrid Nicotiana glutinosa x N. debneyi. Polypeptide patterns from control roots and from roots infected by Glomus mosseae or G. intraradices were resolved by two-dimensional polyacrylamide gel electrophoresis and followed in a time-course analysis. Arbuscular mycorrhizal infection led to significant modifications in polypeptide patterns with: (a) decreased amounts of some polypeptides, (b) increased accumulation of others, and (c) appearance of newly-induced polypeptides. Comparisons made during infection development by the two Glomus species demonstrated that protein modifications changed in relation to the mycorrhizal state of the tobacco roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206783
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  • 56
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    Expression and inheritance pattern of two foreign genes in petunia (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 433-440 
    Details
    ISSN: 1432-2242
    Keywords: Agrobacterium ; Transformation ; Gene expression ; Petunia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic petunia (Petunia hybrida Vilm.) plants were obtained from Agrobacterium-mediated shoot apex transformation. Studies at the phenotypic as well as molecular level established both the presence of the NPT II (neomycin phosphotransferase II) and GUS (β-glucuronidase) genes and their level of activity. Twenty-nine primary transformed plants showed varying patterns of phenotype expression of both genes. NPT II and GUS expression in 7 primary plants over a 4-month interval showed varying levels of gene expression within and among individual plants. All primary transgenic plants were self-pollinated and backcrossed to establish the inheritance patterns of both genes. Mendelian and non-Mendelian inheritance patterns for both genes were observed. Analysis of the progeny showed poor transmission of the foreign genes through the pollen especially when two or more bands were present in the Southern hybridization. Most plants whose progeny segregated in Mendelian ratios for either the NPT II or GUS gene had just one copy of the gene. In this study where both foreign genes were examined in both self and test crosses, no transgenic plant showed Mendelian patterns of inheritance for both foreign traits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223657
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  • 57
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    Cybridization in Nicotiana tabacum L. using double inactivation of parental protoplasts and post-fusion selection based on nuclear-encoded and chloroplast-encoded marker genes (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 1017-1022 
    Details
    ISSN: 1432-2242
    Keywords: Agrobacterium ; Iodoacetamide Nicotiana protoplast fusion ; Nitrosomethyl urea Rhodamine 6G ; X-irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An effective selection system preceded by double inactivation of parental protoplasts was used to transfer Nicotiana suaveolens Leh. cytoplasmic male sterility into a commercial tobacco (N. tabacum L.) breeding line. Mesophyll protoplasts from transformed plants of N. tabacum cultivar WZ2-3-1-1 possessing a neomycin phosphotransferase II gene were used as the nuclear donors, while those isolated from N. suaveolens plants carrying a chloroplast mutation for resistance to spectinomycin, induced using nitrosomethyl urea, were the cytoplasm donors in somatic cybridizations. Prior to fusion, nuclear donor protoplasts were inactivated with iodoacetamide or rhodamine 6G, while those of the cytoplasm donor were inactivated by X-irradiation. The resultant microcalli were cultured on a shoot regeneration medium containing both kanamycin and spectinomycin to select cybrids. Only regenerants that had typical characteristics of the N. tabacum cultivar were selected for transfer to the glasshouse. Four putative cytoplasmic male-sterile (CMS) plants, out of a total of 44 regenerated plants transferred to the glasshouse, were obtained. Intraspecific somatic transfers of the CMS trait between N. tabacum cultivars with distinctlydifferent morphologies using single inactivation and nonselective shoot regeneration medium were demonstrated. The implications of the results for practical tobacco breeding as a means of circumventing lengthy backcrossing procedures are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220810
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    Transformation of protoplasts and intact cells from slowly growing embryogenic callus of wheat (Triticum aestivum L.) (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 577-582 
    Details
    ISSN: 1432-2242
    Keywords: Wheat ; Transformation ; Agrobacterium ; Electroporation ; Polyethylene glycol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A procedure for culturing protoplasts from slowly growing embryogenic calli of wheat was developed. The procedure was dependent on the ability to isolate large numbers of culturable protoplasts from slowly growing embryogenic callus. Approximately 68% of the isolated protoplasts divided, and 22% formed colonies; of the latter, 67% continued to proliferate. Plating efficiency was reduced when protoplasts were transformed by polythylene glycol, electroporation, and/or Agrobacterium. Intact cells were also directly transformed by electroporation. Direct electroporation of the Agrobacterium binary vector into intact cells resulted in a significant increase of GUS activity over the control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222451
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  • 59
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    Electronic Resource
    T-DNA-insert-independent mutations induced in transformed plant cells duringAgrobacterium co-cultivation (1994)
    Springer
    Transgenic research 3 (1994), S. 317-325 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium ; mutagenesis ; Nicotiana plumbaginifolia ; nitrate reductase ; ploidy ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transformation frequencies were determined for 1n, 2n, and 4n Nicotiana plumbaginifolia protoplast cultures inAgrobacterium-mediated gene transfer experiments. An unexpected large drop (50%) in plating efficiencies was observed in the non-selected (control) 1n populations after transformation treatment with virulent strains. This effect was not observed in the 2n or 4n cultures or in the 1n cultures when treated with avirulent bacteria. The mortality was disproportionally high and could not be explained by the low (0.1–0.5%) transformation efficiency in the 1n population, indicating mutagenesis of the cell populations independently from the T-DNA insertions. Mutagenesis was also indicated in gene tagging experiments where nitrate reductase-deficient (NR−) mutants were selected from haploidNicotiana plumbaginifolia protoplasts, as well as from leaf disc cultures or protoplasts of diploid plants that were heterozygotic for a mutation either in the NR apoenzyme gene (nia/wt) or one of the molybdenum-containing cofactor genes (cnxA/wt), afterAgrobacterium co-cultivation. The chlorate-resistant isolates were tested for the T-DNA-specific kanamycin resistance trait only after NR-deficiency had been established. Thirty-nine independent NR-deficient mutants were analysed further by Southern blot hybridization. There was no indication of integrated T-DNA sequences in the mutated NR genes, despite the fact that NR-deficient cells were found more frequently in cell populations which became transformed during the treatment than in the populations which did not. These observations suggest that transformation-competent cells undergo mutagenesis during theAgrobacterium gene transfer process not only as a result of stable integration events, but also through accompanying events that do not result in major changes in the mutated loci. The nature of these changes at the molecular level remains to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973592
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    Tissue specific expression of an α-skeletal actin-lacZ fusion gene during development in transgenic mice (1994)
    Springer
    Transgenic research 3 (1994), S. 59-66 
    Details
    ISSN: 1573-9368
    Keywords: α-actin ; transgenic mice ; gene expression ; muscle ; embryos ; lacZ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic mice carrying a chimaeric transgene containing 730 bp of the 5′-flanking sequences and the entire first intron of the rat α-skeletal actin gene fused to thelacZ reporter gene have been produced by microinjection. ThelacZ reporter gene was used to verify the suitability of using the rat α-actin promoter elements to target expression of genes of agricultural and therapeutic value exclusively to skeletal and heart muscle cells and fibres of transgenic mice. Expression of the transgene indicates a tightly regulated developmental and muscle specific control of the rat α-skeletal actin gene, making it a useful promoter for gene targeting to muscle tissues. The cells destined to form muscle tissues in these transgenic mice are readily visualized in intact embryos by staining for β-galactosidase activity, making them a suitable animal model for studying the origin and development of skeletal and cardiac muscle tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01976028
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    Complementation of an alcohol dehydrogenase-deficientNicotiana plumbaginifolia mutant by transformation with theArabidopsis thaliana Adh gene (1994)
    Springer
    Transgenic research 3 (1994), S. 376-387 
    Details
    ISSN: 1573-9368
    Keywords: alcohol dehydrogenase ; Arabidopsis thaliana ; functional complementation ; gene expression ; Nicotiana plumbaginifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An alcohol dehydrogenase-deficient (ADH) mutant ofNicotiana plumbaginifolia, selected on the basis of ethanol resistance, was restored for ADH activity by transformation with anAdh gene fromArabidopsis thaliana expressed under the control of its own promoter or the CaMV 35S promoter. The expression in various organs (seed, root, leaf and pollen) was analysed at the protein and RNA levels as well as byin situ detection of ADH activity. The analysis of spatial and temporal regulation of theA. thaliana Adh gene expression suggests that ADH expression is controlled at the transcriptional level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01976769
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    Spurious localizations of diX-indigo microcrystals generated by the histochemical GUS assay (1994)
    Springer
    Transgenic research 3 (1994), S. 176-181 
    Details
    ISSN: 1573-9368
    Keywords: Agrobacterium ; β-glucuronidase ; cytoenzymology ; reporter gene ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For several models expressing theuidA orgus reporter gene with or without a presequence for mitochondrial targeting, we have demonstrated that the compartmentation of β-glucuronidase (E.C. 3.2.1.31) activity was not in agreement within situ localization of the diX-indigo microcrystals generated by the cytoenzymological GUS assay. These crystals were generally associated with the various cytomembranes and lipid inclusions. Experiments with purified β-glucuronidase or withgus-expressing bacteria incubated with 5-bromo-4-chloro-3-indolyl-β-d-glucuronide and maize oil-phosphate buffer emulsion indicated that the intermediate products resulting from the GUS assay actively diffused and crystallized preferentially in association with lipids, sometimes far from the site of enzyme activity. This phenomenon could not be suppressed by the addition of potassium ferricyanide in the incubation medium. These findings are discussed with regard to previously reported biochemical and histochemical data on animal tissues, and focus on the necessity for caution in studies of tissue-specific gene expression using the GUS assay, particularly for lipid-rich plant models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973985
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    Carbohydrate binding activities ofBradyrhizobium japonicum: IV. Effect of lactose and flavones on the expression of the lectin, BJ38 (1994)
    Springer
    Glycoconjugate journal 11 (1994), S. 363-370 
    Details
    ISSN: 1573-4986
    Keywords: lectin ; gene expression ; cell-cell adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract BJ38 is a galactose/lactose-specific lectin (M r ∼ 38000) found at one pole ofBradyrhizobium japonicum. It has been implicated in mediating the adhesion of the bacteria to soybean roots, leading to the establishment of a nitrogen-fixing symbiosis. When the ligand lactose is added to cultures of the bacteria for at least 1 h prior to harvesting the cells for BJ38 isolation, the yield of the protein was found to be elevated in a dose-dependent fashion. Half maximal stimulation was observed at ∼ 50 µm; the effect was saturated at ∼ 1mm, where a 10-fold higher yield of BJ38 was obtained. Saccharides with a lower affinity for BJ38 than lactose yielded a correspondingly smaller induction effect when compared at a concentration of 1mm. The higher level of BJ38 induced by lactose is also manifested by an elevated amount of BJ38 detectable at the cell surface and by a higher number ofB. japonicum cells adsorbed onto soybean cells. Surprisingly, the induction of BJ38 expression seen with lactose was also observed with certain, but not all, flavonoids that induce thenod genes of the bacteria; genistein mimicked the induction observed with lactose, whereas luteolin failed to stimulate BJ38 production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00731210
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    Recombinant protein expression in aDrosophila cell line: comparison with the baculovirus system (1994)
    Springer
    Cytotechnology 15 (1994), S. 139-144 
    Details
    ISSN: 1573-0778
    Keywords: Baculovirus ; cell culture ; Drosophila ; gene expression ; insect cell ; metallothionein promoter ; recombinant protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In this report, we compare two different expression systems: baculovirus/Sf9 and stable recombinantDrosophila Schneider 2 (S2) cell lines. The construction of a recombinant S2 cell line is simple and quick, and in batch fermentations the cells have a doubling time of 20 hours until reaching a plateau density of 20 million cells/ml. Protein expression is driven by theDrosophila Metallothionein promoter which is tightly regulated. When expressed in S2 cells, the extracellular domain of human VCAM, an adhesion molecule, is indistinguishable from the same protein produced by baculovirus-infected Sf9 cells. Additionally, we present data on the expression of a seven trans-membrane protein, the dopamine D4 receptor, which has been successfully expressed in both systems. The receptor integrates correctly in the S2 membrane, binds [3H]spiperone with high affinity and exhibits pharmacological characteristics identical to that of the receptor expressed in Sf9 and mammalian cells. The general implications for large scale production of recombinant proteins are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00762388
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    The NocR repressor-activator protein regulates expression of the nocB and nocR genes of Agrobacterium tumefaciens (1994)
    Springer
    Molecular genetics and genomics 244 (1994), S. 367-373 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Nopaline ; Repressor Activator ; LysR family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The NocR protein of Agrobacterium tumefaciens was found to regulate expression of the divergently transcribed nocB and nocR genes of the pTiT37 nopaline catabolism (noc) region. Experiments using the firefly luciferase (luc) gene as reporter demonstrated that NocR represses and activates transcription from the nocB promoter in the absence and presence of nopaline, respectively. NocR also negatively autoregulates its own synthesis irrespective of the presence of nopaline. Regulation of expression of both nocB and nocR is mediated by binding of the NocR protein to the nocR promoter. A 12 by symmetrical sequence, which lies 3 by downstream of the −10 hexamer of the nocR promoter, was confirmed to be essential for binding of the NocR protein. Functional localization of the nocB and nocR promoters verified that they do not overlap at all, and that the interrupted dyad, at which NocR binds, is 137 by upstream of the regulated nocB promoter. The in vivo and in vitro results described here and those published previously suggest that a novel type of regulatory mechanism, which may involve changes in DNA topology, controls gene expression in the noc operon of pTiT37.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286688
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  • 66
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    Agrobacterium vitis nopaline Ti plasmid pTiAB4: relationship to other Ti plasmids and T-DNA structure (1994)
    Springer
    Molecular genetics and genomics 245 (1994), S. 493-505 
    Details
    ISSN: 1617-4623
    Keywords: Agrobacterium ; Bacterial evolution ; Nopaline strains ; Ti plasmids ; Grapevine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Ti plasmid of the Agrobacterium vitis nopaline-type strain AB4 was subcloned and mapped. Several regions of the 157 kb Ti plasmid are similar or identical to parts of the A. vitis octopine/cucumopine (o/c)-type Ti plasmids, and other regions are homologous to the nopaline-type Ti plasmid pTiC58. The T-DNA of pTiAB4 is a chimaeric structure of recent origin: the left part is 99.2% homologous to the left part of the TA-DNA of the o/c-type Ti plasmids, while the right part is 97.1 % homologous to the right part of an unusual nopaline T-DNA recently identified in strain 82.139, a biotype Il strain from wild cherry. The 3′ non-coding regions of the ipt genes from pTiAB4 and pTi82.139 are different from those of other ipt genes and contain a 62 by fragment derived from the coding sequence of an ipt gene of unknown origin. A comparison of different ipt gene sequences indicates that the corresponding 62 by sequence within the coding region of the AB4 ipt gene has been modified during the course of its evolution, apparently by sequence transfer from the 62 by sequence in the 3′ non-coding region. In pTi82.139 the original coding region of the ipt gene has remained largely unmodified. The pTiAB4 6b gene differs from its pTi82.139 counterpart by the lack of a 12 by repeat in the 3′ part of the coding sequence. This leads to the loss of four glutamic acid residues from a series of ten. In spite of these differences, the ipt and 6b genes of pTiAB4 are functional. Our results provide new insight into the evolution of Agrobacterium Ti plasmids and confirm the remarkable plasticity of these genetic elements. Possible implications for the study of bacterial phylogeny are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302262
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    Genetic manipulation in vesicular-arbuscular mycorrhizal fungi (1994)
    Springer
    Plant and soil 159 (1994), S. 171-178 
    Details
    ISSN: 1573-5036
    Keywords: Agrobacterium ; Gigaspora margarita ; Glomus intraradix ; PCR ; mycorrhizae ; rDNA gene ; root organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The symbiosis between vesicular-arbuscular mycorrhizal (VAM) fungi and host plants develops after successful interactions between both partners. These interactions probably involve signal molecules produced by the host plant, by the fungi, or by both. So far the biotrophic status of VAM fungi has hampered the understanding of the processes regulating their physiology. However, among different methods for co-cultivating VAM fungi, root organ cultures (ROC) appear to be a useful technique for studying VAM development. This system has been useful in defining the nutritional requirements of VAM fungi in the precolonization stage and in obtaining axenic fungal material in various developmental stages. The work discussed here focuses on the application of Polymerase Chain Reaction (PCR) technology and the potential of promoting hyphal growth in the absence of the plant. These techniques are being used to study VAM fungi in two main areas. The first concerns the determination of the DNA sequences coding for the SSU ribosomal RNA of two VAM fungi. This approach has allowed the design of specific primers for the rapid identification and quantification of VAM fungi. The second area of research concerns the potential use of PCR technology to study selective expression of specific genes during fungal spore development in defined in vitro conditions. The achievement of this future prospect depends on the ability to prepare PCR-based cDNA libraries from small amounts of fungal material after stimulation of hyphal growth with CO2 and plant flavonols.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000106
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    Traits of transgenic Atropa belladonna doubly transformed with different Agrobacterium rhizogenes strains (1994)
    Springer
    Plant cell, tissue and organ culture 38 (1994), S. 257-262 
    Details
    ISSN: 1573-5044
    Keywords: Agrobacterium ; Atropa belladonna ; double transformation ; phytohormone content ; tropane alkaloids ; viviparous leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hairy root cultures of Atropa belladonna L. were established by infection either with Agrobacterium rhizogenes ATCC 15834 or MAFF 03-01724, and transgenic plants were obtained from both hairy root cultures. Doubly transformed roots were induced by re-infection of the leaf segments of transgenic Atropa belladonna plants (A. rhizogenes 15834) with MAFF 03-01724. Shoots and viviparous leaves were regenerated from the doubly transformed roots. The genetic transformation was determined by the opine assay (agropine, mannopine and/or mikimopine) and polymerase chain reaction. Physiological changes and tropane alkaloid biosynthesis in the hairy roots (singly and doubly transformed) were investigated. The alkaloid content in the doubly transformed root strain was intermediate as compared to the root strains which were singly transformed. On the other hand endogenous IAA levels in doubly transformed roots were significantly decreased compared to both singly transformed roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00033885
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    UV-B damage and protection at the molecular level in plants (1994)
    Springer
    Photosynthesis research 39 (1994), S. 475-489 
    Details
    ISSN: 1573-5079
    Keywords: DNA repair ; flavonoids ; gene expression ; oxidative stress ; photosynthesis ; promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Influx of solar UV-B radiation (280–320 nm) will probably increase in the future due to depletion of stratospheric ozone. In plants, there are several targets for the deleterious UV-B radiation, especially the chloroplast. This review summarizes the early effects and responses of low doses of UV-B at the molecular level. The DNA molecules of the plant cells are damaged by UV due to the formation of different photoproducts, such as pyrimidine dimers, which in turn can be combatted by specialized photoreactivating enzyme systems. In the chloroplast, the integrity of the thylakoid membrane seems to be much more sensitive than the activities of the photosynthetic components bound within. However, the decrease of mRNA transcripts for the photosynthetic complexes and other chloroplast proteins are among very early events of UV-B damage, as well as protein synthesis. Other genes, encoding defence-related enzymes, e.g., of the flavonoid biosynthetic pathway, are rapidly up-regulated after commencement of UV-B exposure. Some of the cis-acting nucleotide elements and trans-acting protein factors needed to regulate the UV-induced expression of the parsley chalcone synthase gene are known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014600
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    Acclimation of photosynthetic proteins to rising atmospheric CO2 (1994)
    Springer
    Photosynthesis research 39 (1994), S. 413-425 
    Details
    ISSN: 1573-5079
    Keywords: elevated CO2 ; gene expression ; Rubisco ; rbcL ; rbcS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this review we discuss how the photosynthetic apparatus, particularly Rubisco, acclimates to rising atmospheric CO2 concentrations (ca). Elevated ca alters the control exerted by different enzymes of the Calvin cycle on the overall rate of photosynthetic CO2 assimilation, so altering the requirement for different functional proteins. A decreased flux of carbon through the photorespiratory pathway will decrease requirements for these enzymes. From modeling of the response of CO2 uptake (A) to intracellular CO2 concentration (ci) it is shown that the requirement for Rubisco is decreased at elevated ca, whilst that for proteins limiting ribulose 1,5 bisphosphate regeneration may be increased. This balance may be altered by other interactions, in particular plasticity of sinks for photoassimilate and nitrogen supply; hypotheses on these interactions are presented. It is speculated that increased accumulation of carbohydrate in leaves developed at elevated ca may signal the ‘down regulation’ of Rubisco. The molecular basis of this ‘down regulation’ is discussed in terms of the repression of photosynthetic gene expression by the elevated carbohydrate concentrations. This molecular model is then used to predict patterns of acclimation of perennials to long term growth in elevated ca.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014595
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    Mitochondrial DNA diseases: Histological and cellular studies (1994)
    Springer
    Journal of bioenergetics and biomembranes 26 (1994), S. 301-310 
    Details
    ISSN: 1573-6881
    Keywords: Mitochondrial encephalomyopathy ; mitochondrial DNA ; gene expression ; protein translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Large-scale deletions and tRNA point mutations in mitochondrial DNA (mtDNA) are associated with a variety of different mitochondrial encephalomyopathies. Skeletal muscle in these patients shows a typical pathology, characterized by the focal accumulation of large numbers of morphologically and biochemically abnormal mitochondria (ragged-red fibers). Both mtDNA deletions and tRNA point mutations impair mitochondrial translation and produce deficiencies in oxidative phosphorylation. However, mutant and wild-type mtDNAs co-exist (mtDNA heteroplasmy) and the translation defect is not expressed until the ratio of mutant: wild-type mtDNAs exceeds a specific threshold. Below the threshold the phenotype can be rescued by intramitochondrial genetic complementation. The mosaic expression of the skeletal muscle pathology is thus determined by both the cellular and organellar distribution of mtDNA mutants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00763101
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    PC12 variants deficient in norepinephrine transporter mRNA have wild type activities of several other related transporters (1994)
    Springer
    Neurochemical research 19 (1994), S. 743-751 
    Details
    ISSN: 1573-6903
    Keywords: Neurotransmitters ; reuptake ; PC12 ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Wild type PC12 pheochromocytoma cells express a Na+-dependent norepinephrine transporter that operates in the uptake of catecholamines. In addition to the previously described Na+-dependent system A for the uptake of α-amino-isobutyric acid and system Gly for glycine, we have identified two other Na+-dependent transporter systems for amino acid uptake in these cells: 1) system β for β-alanine and taurine; and 2) a system for creatine. Uptake of α-amino-isobutyric acid, glycine, β-alanine, and creatine is not affected in some PC12 variants that were previously shown to be deficient in catecholamine uptake and to have decreased levels of norepinephrine transporter mRNA. We have isolated two PC12 cDNA clones that are essentially identical in sequence to recently reported cDNAs for rat brain taurine and creatine transporters, respectively, and a third cDNA that appears to code for a novel transporter. mRNAs for these three transporters are present at wild type levels in those variants that express no or little norepinephrine transporter mRNA. These results support the notion that the expression of catecholamine reuptake transporters may be particularly susceptible to down-regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00967715
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  • 73
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    Mechanisms of EGF receptor regulation in breast cancer cells (1994)
    Springer
    Breast cancer research and treatment 31 (1994), S. 227-236 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptor ; gene expression ; hormone-indepence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Overexpression of the EGF receptor in breast cancer correlates with poor prognosis and failure on endocrine therapy for both ER−/EGFR+ and ER+/EGFR+ tumors, suggesting a role for EGFR in the progression to hormone independence. The identification of specific DNase I hypersensitive site patterns for the EGFR gene in ER+ vs. ER− cells implicates regions of the EGFR first intron in up-regulation of EGFR, while estrogen regulation studies indicate the involvement of a repressor(s) in the maintenance of low levels of EGFR. Based on these findings, a multi-step model is proposed for the progression of breast cancer from a hormone-dependent, ER+/EGFR- phenotype to an aggressive, hormone-independent, ER−/EGFR+ stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666156
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  • 74
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    Effect of a new cholecystokinin antagonist (FK 480) on gene expression of cholecystokinin and secretin in rat intestine (1994)
    Springer
    Journal of gastroenterology 29 (1994), S. 385-387 
    Details
    ISSN: 1435-5922
    Keywords: CCK antagonist (FK 480) ; gene expression ; CCK ; secretin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of a new cholecystokinin (CCK) antagonist (FK 480; 0.1 mg/kg per day given by intragastric administration to rats for 3 days) on the expression of the CCK and secretin genes, plasma CCK immunoreactivity, and CCK content in the intestinal mucosa were examined. FK 480 increased the level of CCK mRNA in the intestine to 1.7 times the level in control rats, but did not affect the level of secretin mRNA. It did not increase plasma CCK immunoreactivity or CCK content in the intestinal mucosa. These results suggest that the ingested FK 480 directly increased CCK mRNA level in the intestine and produced a dissociation between the synthesis and release of CCK.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02358383
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  • 75
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    Photosynthetic electron transport and anaerobic metabolism in purple non-sulfur phototrophic bacteria (1994)
    Springer
    Antonie van Leeuwenhoek 66 (1994), S. 151-164 
    Details
    ISSN: 1572-9699
    Keywords: purple non-sulfur bacteria ; Rhodobacter ; photosynthesis ; CO2 fixation ; anaerobic respiration ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Purple non-sulfur phototrophic bacteria, exemplifed byRhodobacter capsulatus andRhodobacter sphaeroides, exhibit a remarkable versatility in their anaerobic metabolism. In these bacteria the photosynthetic apparatus, enzymes involved in CO2 fixation and pathways of anaerobic respiration are all induced upon a reduction in oxygen tension. Recently, there have been significant advances in the understanding of molecular properties of the photosynthetic apparatus and the control of the expression of genes involved in photosynthesis and CO2 fixation. In addition, anaerobic respiratory pathways have been characterised and their interaction with photosynthetic electron transport has been described. This review will survey these advances and will discuss the ways in which photosynthetic electron transport and oxidation-reduction processes are integrated during photoautotrophic and photoheterotrophic growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00871637
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  • 76
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    Strategies for improving heterologous protein production from filamentous fungi (1994)
    Springer
    Antonie van Leeuwenhoek 65 (1994), S. 245-250 
    Details
    ISSN: 1572-9699
    Keywords: Aspergillus ; gene expression ; heterologous protein ; protein secretion ; Trichoderma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Despite the naturally high capacity for protein secretion by many species of filamentous fungi, secteted yields of many heterologous proteins have been comparatively low. The strategies for yield improvement have included the use of strong homologous promoters, increased gene copy number, gene fusions with a gene encoding a naturally well-secreted protein, protease-deficient host strains and screening for high yields following random mutagenesis. Such approaches have been effective with some target heterologous proteins but not others. Approaches used in heterologous protein production from filamentous fungi are discussed and a perspective on emerging strategies is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00871952
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  • 77
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    Photobiology of Bacteria (1994)
    Springer
    Antonie van Leeuwenhoek 65 (1994), S. 331-347 
    Details
    ISSN: 1572-9699
    Keywords: photoactive proteins ; photoreceptors ; chromophores ; energy transduction ; light signalling ; phototaxis ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The field of photobiology is concerned with the interactions between light and living matter. For Bacteria this interaction serves three recognisable physiological functions: provision of energy, protection against excess radiation and signalling (for motility and gene expression). The chemical structure of the primary light-absorbing components in biology (the chromophores of photoactive proteins) is surprisingly simple: tetrapyrroles, polyenes and derivatised aromats are the most abundant ones. The same is true for the photochemistry that is catalysed by these chromophores: this is limited to light-induced exciton- or electron-transfer and photoisomerization. The apoproteins surrounding the chromophores provide them with the required specificity to function in various aspects of photosynthesis, photorepair, photoprotection and photosignalling. Particularly in photosynthesis several of these processes have been resolved in great detail, for others at best only a physiological description can be given. In this contribution we discuss selected examples from various parts of the field of photobiology of Bacteria. Most examples have been taken from the purple bacteria and the cyanobacteria, with special emphasis on recently characterised signalling photoreceptors inEctothiorhodospira halophila and inFremyella diplosiphon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00872217
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  • 78
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    Powdery mildew resistance in Aegilops tauschii coss. and synthetic hexaploid wheats (1994)
    Springer
    Genetic resources and crop evolution 41 (1994), S. 151-158 
    Details
    ISSN: 1573-5109
    Keywords: Triticum aestivum ; Aegilops tauschii (syn. Ae. squarrosa) ; Erysiphe graminis f. sp. tritici resistance genes ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A collection of 400 Ae. tauschii (syn. Ae. squarrosa) Coss. accessions were screened for powdery mildew resistance based on the response patterns of 13 wheat cultivars/lines possessing major resistance genes to nine differential mildew isolates. 106 accessions showed complete resistance to all isolates, and 174 accessions revealed isolate-specific resistance, among which were 40 accessions exhibiting an identical response pattern as wheat cultivar ‘Ulka/*8Cc’ which is known to possess resistance gene Pm2. Expression of both complete and isolate-specific resistance from Ae. tauschii was observed in some synthetic hexaploid wheats derived from four mildew susceptible T. durum Desf. parents, each crossed with five to 38 resistant diploid Ae. tauschii accessions. Synthetic amphiploids involving different combinations of T. durum and Ae. tauschii generally showed a decrease in resistance compared with that expressed by the Ae. tauschii parental lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00051631
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  • 79
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    Molecular biology of C4 phosphoenolpyruvate carboxylase: Structure, regulation and genetic engineering (1994)
    Springer
    Photosynthesis research 39 (1994), S. 115-135 
    Details
    ISSN: 1573-5079
    Keywords: C4 photosynthesis ; gene expression ; oligomerization ; phosphorylation-dephosphorylation cascade ; PEPC-protein kinase ; site-directed mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three to four families of nuclear genes encode different isoforms of phosphoenolpyruvate (PEP) carboxylase (PEPC): C4-specific, C3 or etiolated, CAM and root forms. C4 leaf PEPC is encoded by a single gene (ppc) in sorghum and maize, but multiple genes in the C4-dicot Flaveria trinervia. Selective expression of ppc in only C4-mesophyll cells is proposed to be due to nuclear factors, DNA methylation and a distinct gene promoter. Deduced amino acid sequences of C4-PEPC pinpoint the phosphorylatable serine near the N-terminus, C4-specific valine and serine residues near the C-terminus, conserved cysteine, lysine and histidine residues and PEP binding/catalytic sites. During the PEPC reaction, PEP and bicarbonate are first converted into carboxyphosphate and the enolate of pyruvate. Carboxyphosphate decomposes within the active site into Pi and CO2, the latter combining with the enolate to form oxalacetate. Besides carboxylation, PEPC catalyzes a HCO3 --dependent hydrolysis of PEP to yield pyruvate and Pi. Post-translational regulation of PEPC occurs by a phosphorylation/dephosphorylation cascade in vivo and by reversible enzyme oligomerization in vitro. The interrelation between phosphorylation and oligomerization of the enzyme is not clear. PEPC-protein kinase (PEPC-PK), the enzyme responsible for phosphorylation of PEPC, has been studied extensively while only limited information is available on the protein phosphatase 2A capable of dephosphorylating PEPC. The C4 ppc was cloned and expressed in Escherichia coli as well as tobacco. The transformed E. coli produced a functional/phosphorylatable C4 PEPC and the transgenic tobacco plants expressed both C3 and C4 isoforms. Site-directed mutagenesis of ppc indicates the importance of His138, His579 and Arg587 in catalysis and/or substrate-binding by the E. coli enzyme, Ser8 in the regulation of sorghum PEPC. Important areas for further research on C4 PEPC are: mechanism of transduction of light signal during photoactivation of PEPC-PK and PEPC in leaves, extensive use of site-directed mutagenesis to precisely identify other key amino acid residues, changes in quarternary structure of PEPC in vivo, a high-resolution crystal structure, and hormonal regulation of PEPC expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029380
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  • 80
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    Design and application of antisense oligonucleotides in cell culture,in vivo, and as therapeutic agents (1994)
    Springer
    Cellular and molecular neurobiology 14 (1994), S. 557-568 
    Details
    ISSN: 1573-6830
    Keywords: antisense oligonucleotides ; gene expression ; pharmacology ; drug design ; cell cultures ; brain research
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Synthetic oligonucleotides can inhibit the expression of a gene in a sequence specific manner on the transcriptional and translational level. These molecules are usually referred to as antisense oligonucleotides. 2. Antisense mediated inhibition of gene expression is a valuable tool to analyze the function of a genein vivo and can also be used for therapeutic gene suppression. 3. A number of factors such as the mode of action, specificity, chemistry, and pharmacology must be carefully considered for the design and successful application of antisense oligonucleotides. 4. Assay systems and controls must be chosen as to assure that the observed biological effects of antisense oligonucleotides do in fact reflect the result of a specific gene inhibition. 5. This article critically discusses these factors in view of the literature and our own experience with a wide range of cell types and animal models, targeting different genes. The emphasis is on the use of phosphorothioate oligodeoxynucleotides in cell cultures,in vivo, and as potential drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02088837
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  • 81
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    Coordinated expression of five tropomyosin isoforms and β-actin in astrocytes treated with dibutyryl cAMP and cytochalasin D (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 303-316 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; cell culture ; gene expression ; Northern blot ; serum-induction ; rat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin D and dBcAMP cause cultured astrocytes to change from flat cells to retrated process-bearing cells. F-actin was present throughout cells stimulated with dBcAMP for 16 h, whereas cytochalasin D caused F-actin to form massive aggregates at the tips of the cell processes. The two drugs differently regulated the expression of both β-actin and tropomyosin genes in astrocytes cultured in the presence or absence of serum: dBcAMP caused down-regulation and cytochalasin D caused up-regulation. Northern blot analyses indicated that: (1) serum deprivation halved the concentration of all tropomyosin transcripts (TM-1, TM-2, TM-4, TMBr-1, TMBr-2). Serum induced TM-4 via transcriptional activation, independent of protein synthesis, (2) dBcAMP induced down-regulation of β-actin (-50%) and tropomyosin transcripts (-35 to 52%) even in the presence of serum. The concentration of profilin mRNA decreased in dBcAMP-reactive astrocytes (-46%). The decrease in β-actin mRNA concentration was not blocked by cycloheximide, whereas down-regulation of tropomyosin transcripts was completely reversed when protein synthesis was inhibited, and (3) cytochalasin D induced an increase in the concentration of tropomyosin transcripts (+ 69 to 185%) which was cumulative with serum stimulation. Cytochalasin D induction of both β-actin and TM-4 operated through transcriptional activation, independent of protein synthesis.The production of all tropomyosin transcripts examined here were strictly coordinated with β-actin expression in serum-, dBcAMP- and cytochalasin D-treated astrocytes. This indicates that the differential expression of tropomyosin isoforms occurring during astrocyte maturation is due to more complex regulation than that involved in serum- or cAMP-stimulated astrocytes. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280404
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    From trypanosomes to the nervous system, from molecules to behavior: A survey, on the occasion of the 90th anniversary of Castellani's discovery of the parasites in sleeping sickness (1994)
    Springer
    Neurological sciences 15 (1994), S. 75-87 
    Details
    ISSN: 1590-3478
    Keywords: african sleeping sickness ; trypanosomiasis ; cytokines ; interferon-γ ; suprachiasmatic nucleus ; gene expression ; endogenous rhythms regulation ; sleep-wake cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Aldo Castellani ha descritto nel 1903 la presenza di tripanosomi in pazienti affetti da malattia del sonno. In occasione del 90mo anniversario di questa scoperta, vengono qui presentati i recenti dati ottenuti in un modello sperimentale di tripanosomiasi africana nel ratto. Tale modello ha consentito di apportare notevoli chiarimenti ai meccanismi molecolari e cellulari dei rapporti che intercorrono fra il parassita e l'ospite. Si verifica, infatti, fra il tripanosoma e le cellule T CD8 dell'ospite, uno scambio bidirezionale di segnali. Questo nuovo meccanismo patogenetico di infezione coinvolge un fattore attivante i linfociti secreto dal parassita ed il γ-interferone. Anche un γ-interferone neuronale, recentemente isolato, potrebbe giocare un ruolo nella malattia. L'induzione selettiva di antigeni maggiori di istocompatibilità di classe I ha rivelato il coinvolgimento, nella tripanosomiasi, dei nuclei ipotalamici paraventricolare e sopraottico. Infine, studi basati sull'espressione del gene ad induzione rapidac-fos hanno evidenziato una disregolazione selettiva del nucleo soprachiasmatico dell'ipotalamo, che svolge un ruolo di orologio biologico. Quest'ultimo dato può sottendere la grave alterazione di ritmi endogeni che caratterizza la malattia del sonno.
    Notes: Abstract The observation of Trypanosomes in patients affected by sleeping sickness has been reported in 1903 by Aldo Castellani. On the occasion of the 90th anniversary of this discovery, we here present the findings recently obtained in an experimental model of African trypanosomiasis in the rat. The molecular and cellular mechanisms of the interplay between the parasite and the host have been largely clarified: a bidirectional signalling occurs between trypanosomes and CD8+ T cells of the host animal. This new pathogenetic mechanism of infection involves a lymphocyte triggering factor released by the parasite and interferon-γ. A recently isolated neuronal interferon-γ could also play a role in the disease. The selective induction of major histocompatibility antigens class I has revealed the involvement of the hypothalamic paraventricular and supraoptic nuclei in trypanosomiasis. Finally, studies based on the expression of the immediate early genec-fos have pointed out during the infection a selective dysregulation of the suprachiasmatic nucleus of the hypothalamus, that plays the role of biological clock. The latter finding could account for the disruption of endogenous rhythms in sleeping sickness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02340118
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  • 83
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    Modeling the regulation of bacterial genes producing proteins that strongly influence growth (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 43 (1994), S. 242-257 
    Details
    ISSN: 0006-3592
    Keywords: genetic regulation ; gene expression ; transcriptional regulation ; translational regulation ; RNA polymerase ; rpoBc ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical method for comparing the performance of rival models of bacterial genetic regulation is presented. The particukar difficulties involved in describing the regulated synthesis of proteins that strongly influence cell growth are identiied, and the method is specifically designed to treat such cases. The method employs a mathematical description of intrinsic perturbations occurring during exponential growth to test the performance of regulatory models. Specific models of transcriptional and translational regulation are inserted into a general gene-expression framework in order to determine their control responses. Applying thhis approach to examine the regulation of RNA polymerase synthesis in Eschericia coli provides support for the hypothesis that rpoB translation is regulated by cooperative binding of multiple RNA polymerase molecules to the mRNA. The framework is of a sufficiently general form that the method can be used to study mechanisms involved in controlling synthesis of any bacterial protein. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260430308
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  • 84
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    Expression of the c-myc and Ca-ATPase genes in cardiac muscle during adaptation to repeated stress (1994)
    Springer
    Bulletin of experimental biology and medicine 117 (1994), S. 122-124 
    Details
    ISSN: 1573-8221
    Keywords: gene expression ; c-myc ; Ca-ATPase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the course of adaptation to repeated stress, the expression of the proto-oncogene c-myc found to increase much more rapidly than that of the Ca-ATPase gene. It is suggested that an increase in the level of c-myc expression may activate the structural Ca-ATPase gene and possibly also the heat-shock proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02444120
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    Dual role of osteoblastic proenkephalin derived peptides in skeletal tissues (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 334-339 
    Details
    ISSN: 0730-2312
    Keywords: analgesia ; bone development ; gene expression ; opioids ; tissue regeneration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Proenkephalin encodes a group of small peptides with opiate-like activity, the endogenous opioids, known to function as neurohormones, neuromodulators, and neurotransmitters. Recently, we have demonstrated that in addition to its abundance in fetal brain tissue, proenkephalin is highly expressed in nondifferentiated mesodermal cells of developing fetuses. We identified the skeletal tissues, bone, and cartilage as major sites of proenkephalin expression. To examine the possibility that proenkephalin is involved in bone development we have studied the expression of this gene in bone-derived cells, its modulation by bone active hormones, and the effects of enkephalin-derived peptides on osteoblastic phenotype. Our studies revealed that osteoblastic cells synthesize high levels of proenkephalin mRNA which are translated, and the derived peptides are secreted. Reciprocal interrelationships between osteoblast maturation and proenkephalin expression were established. These results together with our observations demonstrating inhibitory effects of proenkephalin-derived peptides on osteoblastic alkaline phosphatase activity, strongly support the notion that proenkephalin is involved in bone development. A different direction of research by other investigators has established the capability of the opioid system in the periphery to participate in the control of pain. On the basis of these two lines of observation, we would like to present the following hypothesis: The potential of embryonic skeletal tissue to synthesize proenkephalin-derived peptides is retained in the adult in small defined undifferentiated cell populations. This potential is realized in certain situations requiring rapid growth, such as remodeling or fracture repair. We suggest that in these processes, similarly to the situation in the embryo, the undifferentiated dividing cells produce the endogenous opioids. In the adult these peptides may have a dual function, namely participating in the control of tissue regeneration and in the control of pain. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jcb.240550310
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  • 86
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    Nuclear architecture supports integration of physiological regulatory signals for transcription of cell growth and tissue-specific genes during osteoblast differentiation (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 4-15 
    Details
    ISSN: 0730-2312
    Keywords: nucleus ; gene expression ; cell growth ; osteoblast ; nucleosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: During the past several years it has become increasingly evident that the three-dimensional organization of the nucleus plays a critical role in transcriptional control. The principal theme of this prospect will be the contribution of nuclear structure to the regulation of gene expression as functionally related to development and maintenance of the osteoblast phenotype during establishment of bone tissue-like organization. The contributions of nuclear structure as it regulates and is regulated by the progressive developmental expression of cell growth and bone cell related genes will be examined. We will consider signalling mechanisms that integrate the complex and interdependent responsiveness to physiological mediators of osteoblast proliferation and differentiation. The focus will be on the involvement of the nuclear matrix, chromatin structure, and nucleosome organization in transcriptional control of cell growth and bone cell related genes. Findings are presented which are consistent with involvement of nuclear structure in gene regulatory mechanisms which support osteoblast differentiation by addressing four principal questions: (1) Does the representation of nuclear matrix proteins reflect the developmental stage-specific requirements for modifications in transcription during osteoblast differentiation? (2) Are developmental stage-specific transcription factors components of nuclear matrix proteins? (3) Can the nuclear matrix facilitate interrelationships between physiological regulatory signals that control transcription and the integration of activities of multiple promoter regulatory elements? (4) Are alterations in gene expression and cell phenotypic properties in transformed osteoblasts and osteosarcoma cells reflected by modifications in nuclear matrix proteins? There is a striking representation of nuclear matrix proteins unique to cells, tissues as well as developmental stages of differentiation, and tissue organization. Together with selective association of regulatory molecules with the nuclear matrix in a growth and differentiation-specific manner, there is a potential for application of nuclear matrix proteins in tumor diagnosis, assessment of tumor progression, and prognosis of therapies where properties of the transformed state of cells is modified. It is realistic to consider the utilization of nuclear matrix proteins for targeting regions of cell nuclei and specific genomic domains on the basis of developmental phenotypic properties or tissue pathology. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jcb.240550103
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  • 87
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    Signal transduction pathways mediating parathyroid hormone regulation of osteoblastic gene expression (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 321-327 
    Details
    ISSN: 0730-2312
    Keywords: parathyroid hormone ; signal transduction ; osteoblasts ; cAMP ; gene expression ; activator protein-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Parathyroid hormone (PTH) plays a central role in regulation of calcium metabolism. For example, excessive or inappropriate production of PTH or the related hormone, parathyroid hormone related protein (PTHrP), accounts for the majority of the causes of hypercalcemia. Both hormones act through the same receptor on the osteoblast to elicit enhanced bone resorption by the osteoclast. Thus, the osteoblast mediates the effect of PTH in the resorption process. In this process, PTH causes a change in the function and phenotype of the osteoblast from a cell involved in bone formation to one directing the process of bone resorption. In response to PTH, the osteoblast decreases collagen, alkaline phosphatase, and osteopntin expression and increases production of osteocalcin, cytokines, and neutral proteases. Many of these changes have been shown to be due to effects on mRNA abundance through either transcriptional or post-transcriptional mechanisms. However, the signal transduction pathway for the hormone to cause these changes is not completely elucidated in any case. Binding of PTH and PTHrP to their common receptor has been shown to result in activation of protein kinases A and C and increases in intracellular calcium. The latter has not been implicated in any changes in mRNA of osteoblastic genes. On the other hand activation of PKA can mimic all the effects of PTH; protein kinase C may be involved in some responses. We will discuss possible mechanisms linking PKA and PKC activation to changes in gene expression, particularly at the nuclear level. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jcb.240550308
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    Functional integrity of metallothionein genes in testicular cell lines (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 486-495 
    Details
    ISSN: 0730-2312
    Keywords: Metallothionein ; gene expression ; Leydig cell ; Sertoli cell ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The presence and inducibility of the major cadmium (Cd) chelating protein metallothionein (MT) in testicular cells has been controversial. In this study, the induction and production of MT in testicular cells were studied using mouse Leydig and Sertoli cell lines. Metal accumulation was studied by subjecting the cells to increasing levels of Cd. The presence of transcription factors for MT synthesis was analyzed by transfecting the cells with a reporter gene under the control of the MT promoter. The dose- and time-dependent induction of MT were conducted by Northern analyses. Expression of MT genes occurred in both Leydig and Sertoli cells. To avoid cross hybridization of the MT probe with mRNAs encoding testicular metal binding proteins and to investigate the integrity of MT mRNA, isoMT mRNA identification and primer extension experiments were performed. Those studies show that the induced mRNA indeed encodes MT. The biosynthesis of MT was confirmed by following 35S-cysteine incorporation into the protein. Finally, cadmium tolerance of testicular cells is compared with that of fibroblast cells. By these studies, we conclude that the MT genes are functional and inducible in testicular cells. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240550408
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  • 89
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    Electronic Resource
    Localization of erythropoietin mRNA in the rat kidney by polymerase chain reaction (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 54 (1994), S. 239-246 
    Details
    ISSN: 0730-2312
    Keywords: gene expression ; microdissection ; nephron segments ; endothelial cells ; in situ hybridization ; erythropoiesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Erythropoietin (Epo) is a glycoprotein secreted by kidney cells which plays an important role in the regulation of erythropoiesis. Localization of the Epo production by immunohistochemical studies and in situ hybridization has not been definitively established and is still a matter of controversy. Epo and glyceraldehyde 3-dehydrogenase (GAPDH) mRNA levels were determined in total RNA isolated from control and CoCl2-treated rats using a coupled reverse transcriptase/polymerase chain reaction method (RT/PCR). As indicated by the amount of amplification product, Epo mRNA levels were several-fold higher in CoCl2-treated rat kidney. In contrast, GAPDH mRNA levels were similar in control and CoCl2-treated rats. This RT/PCR method was also used to assess the level of Epo and GAPDH mRNA in microdissected nephron segments. All nephron segments tested lacked any detectable levels of Epo mRNA in either control or CoCl2-treated rats. On the other hand, peritubular cells (capillary fraction: afferent/efferent arteriole, vasa recta) were the only cells where the Epo mRNA was detected. Using a specific primer for GAPDH, the RT/PCR method could identify GAPDH mRNA in all microdissected nephron segments where the Epo mRNA was not expressed. Thus, a combination of microdissected nephron segments and RT/PCR enabled us to detect GAPDH mRNA populations in all nephron segments, whereas the failure to detect Epo mRNA in all segments but the capillary fraction, is due to the specific and localized expression of the Epo gene to this fraction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240540212
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  • 90
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    Electronic Resource
    Cellular and clinical perspectives on skeletal insulin-like growth factor I (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 55 (1994), S. 328-333 
    Details
    ISSN: 0730-2312
    Keywords: insulin-like growth factor I ; transcriptional control ; posttranscriptional control ; gene expression ; insulin-like growth factor binding proteins ; osteoblast ; bone formation ; osteoporosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Insulin-like growth factor (IGF) I, a polypeptide synthesized by skeletal cells, is presumed to act as an autocrine regulator of bone formation. IGF I stimulates bone replication of preosteoblastic cells and enhances the differentiated function of the osteoblast. The synthesis of skeletal IGF I is regulated by systemic hormones, most notably parathyroid hormone and glucocorticoids, as well as by locally produced factors, such as prostaglandins and other skeletal growth factors. Whereas hormones and growth factors regulate IGF I synthesis, the exact level of regulation has not been established and may involve both transcriptional and posttranscriptional mechanisms. The IGF I gene contains six exons, and both exon 1 and 2 contain transcription initiation sites. Extrahepatic tissues, including bone, express exon 1 transcripts, and regulation of the exon 1 promoter activity in osteoblasts is currently under study. It is apparent that the regulation of IGF I gene transcription as well as the regulation of mRNA stability is complex and tissue specific. It is possible that abnormalities in skeletal IGF I synthesis or activity play a role in the pathogenesis of bone disorders. In view of its important anabolic actions in bone, it is tempting to postulate the use of IGF I for the treatment of disorders characterized by decreased bone mass. An alternative could be the stimulation of the local production of IGF I in bone. © 1994 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240550309
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  • 91
    Electronic Resource
    Electronic Resource
    Alterations in cellular gene expression without changes in nuclear matrix protein content (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 56 (1994), S. 502-509 
    Details
    ISSN: 0730-2312
    Keywords: MCF10A ; nuclear matrix ; gene expression ; ras ; actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cell metabolism and function are modulated in part by cell and nuclear shape. Nuclear shape is controlled by the nuclear matrix, the RNA-protein skeleton the nucleus, and its interactions with cytoskeletal systems such as intermediate filaments and actin microfilaments. The nuclear matrix plays an important role in cell function and gene expression because active genes are bound to the nuclear matrix whereas inactive genes are not. It is unknown, however, how genes move on and off the matrix, and whether these events require compositional protein changes, i.e., alterations in protein content of the nuclear matrix, or other, more subtle alterations and/or modificatins. The purpose of this investigation was to begin to determine how nuclear matrix protein composition is related to gene expression. We demonstrate that gene expression can change without apparent changes in the protein composition of the nuclear matrix in MCF10A breast epithelial cells.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240560410
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  • 92
    Electronic Resource
    Electronic Resource
    Use of β-lactamase as a secreted reporter of promoter function in yeast (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 497-508 
    Details
    ISSN: 0749-503X
    Keywords: Protein secretion and processing ; gene expression ; killer toxin ; Kex2 protease ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: K1 preprotoxin is the 316 residue precursor of the K1 killer toxin secreted by the yeast Saccharomyces cerevisiae. The SPβla reporter consists of the mature, secreted form of β-lactamase (βla) fused to S and P, two fragments of preprotoxin. S is the N-terminal 34 residues, including the secretion signal. P, a 67 residue ‘processing’ segment with three sites for N-glycosylation, terminates in a Lys Arg site for cleavage by the Kex2 protease. Expression of SPβla in yeast results in efficient secretion, processing by signal peptidase and glycosylation in the endoplasmic reticulum, producing proßla. Kex2 cleavage of proßla in the lumen of a late Golgi compartment releases βla, which accumulates stably in culture media buffered at pH 5·8-7. The half-life of secretion is 11 min at 30°C; 10-12% of the total activity in exponential-phase cells is intracellular, mostly in the form of proßla, indicating that transit from the endoplasmic reticulum to the Golgi is rate limiting. We have used SPβla expression in single- and multi-copy vectors to compare the PGK, GAL1, GAL10, PHO5 and CUP1 promoters under varying nutritional conditions. In exponential-phase cells, secretion of βla over a 40-fold range and up to several μg/ml was proportional to transcript level, demonstrating that SPβla can be employed as a convenient secreted reporter of promoter function in yeast.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320100409
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  • 93
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    The in vivo activation of Saccharomyces cerevisiae plasma membrane H+-ATPase by ethanol depends on the expression of the PMA1 gene, but not of the PMA2 gene (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1439-1446 
    Details
    ISSN: 0749-503X
    Keywords: Plasma membrane H+-ATPase ; ethanol ; gene expression ; PMA1 ; PMA2 ; Saccharomyces cerevisiae ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The expression of the PMA1 and PMA2 genes during Saccharomyces cerevisiae growth in medium with glucose plus increasing concentrations of ethanol was monitored by using PMA1-lacZ and PMA2-lacZ fusions and Northern blot hybridizations of total RNA probed with PMA1 gene. The presence of sub-lethal concentrations of ethanol enhanced the expression of PMA2 whereas it reduced the expression of PMA1. The inhibition of PMA1 expression by ethanol corresponded to a decrease in the content of plasma membrane ATPase as quantified by immunoassays. Although an apparent correspondence could exist between the increase of plasma membrane ATPase activity and the level of PMA2 expression, the maximal level of PMA2 expression remained about 200 times lower than PMA1. On the other hand, ethanol activated the plasma membrane H+-ATPase activity from a strain expressing only the PMA1 ATPase but did not activate that from a strain expressing only the PMA2 ATPase. These results provide evidence that in the presence of ethanol it is the PMA1 ATPase which is activated, probably by a post-translational mechanism and that the PMA2 ATPase is not involved.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320101107
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  • 94
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    Characterization and expression of C/EBP-like genes in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone-induced metamorphosis (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 366-377 
    Details
    ISSN: 0192-253X
    Keywords: C/EBP ; thyroid hormone ; metamorphosis ; gene expression ; Rana cafesbeiana ; bZlP proteins ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Tissue-specific changes in gene expression occur in the liver of Rana cafesbeiana tadpoles undergoing metamorphosis. Many of these changes can be induced precociously by administration of thyroid hormone (TH) to a tadpole or to cultured tadpole liver. While the precise molecular means by which TH exerts a tissue-specific response is unknown, recent studies suggest that the expression of genes which are liver-specific and characteristic of the adult liver phenotype may rely on TH-induction of tissue-specific transcription factors, as well as the thyroid hormone receptor proteins. Guided by this notion, we screened our Rana catesbeiana liver cDNA library and isolated clones, RcC/EBP-1 and -2, encoding Rana homologues of a mammalian transcription factor, C/EBP (CCAAT/enhancer core binding protein), implicated in the expression of liver-specific genes and terminal differentiation of hepatocytes. Gel mobility shift assays demonstrate that the proteins synthesized from these cDNAs bind specifically to the consensus binding site for C/EBP-related proteins. Characterization of the amino acid sequence in the bZlP DNA-binding domains of these proteins suggests that RcC/EBP-1 and -2 encode Rana homologues of C/EBPα and δ, respectively. Hybridization analyses demonstrate that the amount of RcC/EBP-2 mRNAs in tadpole liver remains constant throughout metamorphosis, whereas RcC/EBP-1 mRNAs are up-regulated during both spontaneous and TH-induced metamorphosis. The TH-induced up-regulation of RcC/ EBP-1 mRNAs precedes the up-regulation of liver-specific urea cycle enzyme mRNAs by 6 to 12 hours. These results, coupled with in situ hybridization studies, suggest that RcC/EBP-1 mRNAs encode a transcription factor which may play an early role(s) in the terminal differentiation and/or reprogramming of gene expression in this tadpole's liver cells during both spontaneous and TH-induced metamorphosis. ©1994 WiIey-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150408
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  • 95
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    DNA sequence requirements for the regulation of immobilization antigen a expression in Paramecium tetraurelia (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 443-451 
    Details
    ISSN: 0192-253X
    Keywords: Paramecium tetraurelia ; immobilization antigen ; gene expression ; promoter ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The Paramecium surface proteins (immobilization antigens) are expressed in a mutually exclusive manner; only one antigen is found on the cell surface at a time. Expression of these proteins is regulated in response to environmental cues such as temperature and pH. This regulation has been shown to be controlled at the level of mRNA abundance by transcriptional and post-transcriptional mechanisms. Here, we have studied the transcription and regulated expression of the immobilization antign A gene in Paramecium tetraurelia by transforming an A -deficient strain, d12, with cloned portions of the A gene viamicroinjection. The A gene is approximately 8 kilobases (kb) long with the transcription start site at postion -9 or -8 and the start of translation at position +1. Paramecia transformed with cloned DNA containing A-gene sequences beginning at position -264 and ending 63 base pairs (bp) past the gene's polyadenylation site show properly regulated expression of immobilization antigen A. Lines derived from paramecia transformed with a plasmid containing A-gene sequences starting at position -211, however, show markedly reduced A-gene mRNA levels, and rarely express the A antigen. Nevertheless, cells that do express the A protein exhibit mutual exclusion and normal responses to environmental stimuli. Thus, the 54 bp between -264 and -211, while important for transcription, are not involved in the control of mutual exclusion and responses to environmental chages. Further deletion to position -151 yields similar, but more extreme, results. Therefore, the start of the A-gene promoter lies within the region -264 to -211, with additional sequences affecting transcriptional regulation present between base pairs -211 and -151. Sequences controlling environmental responses and mutual exclusion must be located downstream of position -211. Thus, we have defined regions of DNA necessary for immobilization antigen A expression and have located the approximate position of the A-gene promoter in Paramecium. This work paves the way for a precise mutational analysis of these regions and the first detailed molecular characterization of a Paramecium promoter. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150507
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  • 96
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    Electronic Resource
    Heterochronic expression of an adult muscle actin gene during ascidian larval development (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 51-63 
    Details
    ISSN: 0192-253X
    Keywords: Actin ; ascidian development ; gene expression ; heterochrony ; muscle actin gene ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Adultation is a hetercchronic mode of development in which adult tissues and organs differentiate precociously during the larval phase. We have investigated the expression of an adult muscle actin gene during adultation in the ascidian Molgula citrina. Ascidians contain multiple muscle actin genes which are expressed in the larva, the adult, or during both phases of the life cycle. In ascidian species with conventional larval development, the larval mesenchyme cells, which are believed to be progenitors of the adult mesoderm, remain undifferentiated and do not express the muscle actin genes. In M. citrina, the mesen-chyme cells differentiate precociously during larval development, suggesting a role in adultation. An adult muscle actin gene from M. citrina was obtained by screening a mantle cDNA library with a probe containing the coding region of SpMAl, a Styela plicata adult muscle actin gene. The screen yielded a cDNA clone designated McMAl, which contained virtually the complete coding and 3′ noncoding regions of a muscle actin gene. The deduced McMAl and SpMAl proteins exhibit 97% identity in amino acid sequence and may be encoded by homologous genes. The McMAl gene is expressed in juveniles and adults, but not in larval tail muscle cells, suggesting that it is an adult muscle actin gene. In situ hybridization with a 3′ non-coding region probe was used to determine whether the McMAl gene is expressed during adultation in M. citrina. McMAl mRNA was first detected exclusively in the mesenchyme cells during the late tailbud stage and continued to accumulate in these cells during their migration into the future body cavity and heart primordium in the hatched larva. The McMAl transcripts persisted in mesenchyme cells after larval metamorphosis. It is concluded that an adult muscle actin gene shows a heterochronic shift of expression into the larval phase during adultation in M. citrina.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150107
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  • 97
    Electronic Resource
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    Ontogeny of gene expression in Pomoxis (pisces: Centrarchidae) (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 119-128 
    Details
    ISSN: 0192-253X
    Keywords: Embryogenesis ; gene expression ; isozymes ; Pomoxis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The regulation of gene expression during embryogenesis was investigated in white and black crappie (Pomoxis spp.) and their reciprocal interspecific F1 hybrids. The schedule of morphological development and the timing of isozyme expression were compared among the two species and both reciprocal maternal half-sibling F1 hybrids. Although absolute rates of morphological development differed in response to incubation temperature, relative rates of morphological development (normalized to the onset of retinal pigment deposition) were similar among all crosses. Furthermore, these relative rates were similar to those previously documented for other centrarchid species. To assess differences in ontogenetic patterns of gene expression among the crosses, we examined expression for 39 enzymeencoding loci. Expression was not detected in the embryos for 16 loci due to low or nonexistent activity. Enzymatic activity from eight other loci were continuously detected throughout embryogenesis as a result of maternal enzyme in the egg. However, 15 loci initiated expression during the early development period investigated (fertilization through yolk sac absorption). We observed temporal variability in expression of these 15 loci among the crosses, either in the form of differential expression between parental species or as disturbances in the ontogeny of expression in interspecific hybrids. Such variability in expression suggests that some of the gene regulating mechanisms have diverged since Pomoxis species shared a common ancestral genome. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150202
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  • 98
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    Developmentally regulated expression of fibroblast growth factor receptor genes and splice variants by murine embryonic stem and embryonal carcinoma cells (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 15 (1994), S. 148-154 
    Details
    ISSN: 0192-253X
    Keywords: Fibroblast growth factor ; receptor ; gene expression ; RNA splicing ; embryonic stem cells ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The expression of the four fibroblast growth factor receptor (FGF-R) genes was examined in murine embryonic stem (ES) cells, embryonal carcinoma (EC) cells, and their differentiated derivatives. FGF-R1 and FGF-R4 were found to be expressed constitutively in all samples examined. The expression of FGF-R2 and FGF-R3 was, however found to increase significantly upon differentiation of both ES and EC cells. Examination of splice variants of the third immunoglobulin domain (Iglll) of the extracellular region of the FGF-R2 revealed that whilst Iglllc transcripts were expressed upon ES cell differentiation, Iglllb transcripts (which confer specificity for the ligand FGF-7) were expressed in both ES cells and their differentiated progeny. FGF-R3 transcripts were also expressed in ES cells, but variont FGF-R3 transcripts containing the Iglllb region were expressed upon differentiation. The findings suggest that the repertoire of FGF-R expression in embryonic cell types is developmentally regulated at the level of both gene expression, and alternative splicing and different members of the FGF-R family can exhibit distinct patterns of both gene and splice variant expression. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020150205
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  • 99
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    Butyrate-induced reactivation of the fetal globin genes: A molecular treatment for theβ-hemoglobinophaties (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 133-137 
    Details
    ISSN: 1420-9071
    Keywords: Fetal hemoglobin ; sickle cell anemia ; β thalassemia ; butyrate ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The inherited β-hemoglobinopathies (sickle cell disease and β thalassemia) are the result of a mutation in the adult (β) globin gene. The fetal globin chain, encoded by the γ globin genes, can substitute for the mutated or defective β globin chain, but expression of the γ globin gene is developmentally inactivated prior to birth. Reinducing expression of the normal fetal globin genes is a preferred method of ameliorating sickle cell disease and the β thalassemias. Stimulation of as little as 4–8% fetal globin synthesis in the bone marrow can produce 〉20% fetal hemoglobin in the peripheral circulation, due to enhanced survival of red blood cells containing both sickle and fetal hemoglobin, compared to those containing sickle hemoglobin alone. Butyric acid and butyrate derivatives are generally safe compounds which induce fetal hemoglobin production by stimulating the promoter of the fetal globin genes. An initial trial with the parent compound, delivered as Arginine Butyrate, has demonstrated rapid stimulation of fetal globin expression to levels that have been shown to ameliorate these conditions. Phase 1 trials of an oral butyrate derivative with a long plasma half-life have just begun. These agents now provide a specific new apporach for ameliorating these classic molecular disorders and merit further investigation in larger patient populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01989417
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  • 100
    Electronic Resource
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    Altered proteoglycan gene expression and the tumor stroma (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 447-455 
    Details
    ISSN: 1420-9071
    Keywords: Proteoglycan ; chondroitin sulfate ; decorin ; gene expression ; tumor stroma ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5′ untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon. Furthermore, a transforming growth factor beta (TGF-β)-negative element is present in the promoter region of decorin gene. This regulatory domain is likely to be implicated in the silencing of decorin gene by TGF-β and may contribute to the regulation of this matrix gene in the tumor stroma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923588
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