Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Generation and characterization of variants of mouse hepatoma cells with defects in hepato-specific gene expression. I. Albumin synthesis variants (1982)
    Springer
    Somatic cell and molecular genetics 8 (1982), S. 451-464 
    Details
    ISSN: 1572-9931
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Clonal variants of mouse hepatoma cells that either fail to produce albumin (variant 19/2) or show significantly reduced levels (100-fold less) of albumin production (variant 1/c/1) were isolated from the parental line, Hepa la, after a single exposure to N-methyl-N′-nitrosoguanidine (MNNG). Intracellular levels of albumin in both variants were below detection by our assay. Analyses by cDNA-RNA reassociation kinetics indicate that there are approximately 3900 molecules of cytoplasmic albumin mRNA per cell in the parent and less than 10 molecules per cell in both variants. Southern blotting of the Eco RI restriction fragments of cellular DNA from the parent and variants did not indicate any major deletions in the albumin gene DNA sequences. We conclude that in the two variants studied, processes that regulate albumin production via alterations in the level of cytoplasmic albumin mRNA have been affected. Our analyses have also shown that alpha-fetoprotein (AFP) production is lacking in one variant (19/2) and is slightly reduced in the other (1/c/1). Transferrin secretion is lower than the parental line in both variants. Thus multiple nonlethal defects in hepatic gene expression can be obtained in Hepa la cells in culture that will be useful in determining the number and kinds of genes that control the expression of liver-specific loci.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01538707
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Arabidopsis thaliana small subunit leader and transit peptide enhance the expression ofBacillus thuringiensis proteins in transgenic plants (1992)
    Springer
    Plant molecular biology 20 (1992), S. 81-93 
    Details
    ISSN: 1573-5028
    Keywords: Bacillus thuringiensis ; cry genes ; insect-resistant plants ; transit peptide ; untranslated leaders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of the modified gene for a truncated form of thecryIA(c) gene, encoding the insecticidal portion of the lepidopteran-active CryIA(c) protein fromBacillus thuringiensis var.kurstaki (B.t.k.) HD73, under control of theArabidopsis thaliana ribulose-1,5-bisphosphate carboxylase (Rubisco) small subunitats1A promoter with and without its associated transit peptide was analyzed in transgenic tobacco plants. Examination of leaf tissue revealed that theats1A promoter with its transit peptide sequence fused to the truncated CryIA(c) protein provided a 10-fold to 20-fold increase incryIA(c) mRNA and protein levels compared to gene constructs in which the cauliflower mosaic virus 35S promoter with a duplication of the enhancer region (CaMV-En35S) was used to express the samecryIA(c) gene. Transient expression assays in tobacco protoplasts and the whole plant results support the conclusion that the transit peptide plus untranslated sequences upstream of that region are both required for the increase in expression of the CryIA(c) protein. Furthermore, the CaMV-En35S promoter can be used with theArabidopsis ats1A untranslated leader and transit peptide to increase expression of this protein. While subcellular fractionation revealed that the truncated CryIA(c) protein fused to theats1A transit peptide is located in the chloroplast, the increase in gene expression is independent of targeting of the CryIA(c) protein to the chloroplast. The results reported here provide new insight into the role of 5′ untranslated leader sequences and translational fusions to increase heterologous gene expression, and they demonstrate the utility of this approach in the development of insect-resistant crops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029151
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Secretion and export of IGF-1 in Escherichia coli strain JM101 (1988)
    Springer
    Molecular genetics and genomics 215 (1988), S. 19-25 
    Details
    ISSN: 1617-4623
    Keywords: IGF-1 ; Escherichia coli secretion/export ; LamB leader peptide ; Heterologous gene expression ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The processing of LamB-IGF-1 fusion protein and the export of processed IGF-1 (insulin-like growth-factor-1) into the growth medium was examined in the Escherichia coli host strain, JM101. Several strain or plasmid modifications were tried to increase export of periplasmic (Processed) IGF-1 into the growth medium of JM101. These included: (1) use of a lon null mutant strain to increase accumulation levels of unprocessed LamB-IGF-1 fusion protein; (2) use of an alternative drug resistance marker on the expression plasmid rather than beta-lactamase, thereby reducing any competition for processing of LamB-IGF-1 by signal peptidase; (3) examination of whether phage M13 gene III protein expression caused more periplasmic IGF-1 to be exported into the growth medium due to increased outer membrane permeability; and (4) examination of the effect of E. coli or yeast optimized IGF-1 codons. None of these strain or plasmid modifications caused any significant increase in export of IGF-1 into the growth medium of JM101. Solubility studies of LamB-IGF-1 and processed IGF-1 showed that virtually all of the LamB-IGF-1 and IGF-1 remaining within the cell after a 2 h induction period was insoluble. This implied that only soluble LamB-IGF-1 was processed to IGF-1 and that only soluble IGF-1 was exported into the growth medium. Taken together, the results indicated that LamB-IGF-1 and IGF-1 solubility were the limiting factors in secretion of IGF-1 into the periplasm and export of IGF-1 into the growth medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331297
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...