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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of RNA by Escherichia coli RNA polymerase on the chromosomes of Drosophila melanogaster (1974)
    Springer
    Chromosoma 46 (1974), S. 161-172 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Preparations of polytene chromosomes of D. melanogaster fixed with acetic acid have been used as templates for RNA synthesis by E. coli RNA polymerase complete or core enzymes in the presence of 3H-nucleoside triphosphates. Radioautographic experiments showed that on a single X-chromosome from male larvae twice as much RNA is synthesized as on each of the two female X-chromosomes. Thus, such a heterologous transcription system shows the dosage compensation effect which had been observed earlier for the X-chromosomes in the intact cells in vivo. It is suggested that the dosage compensation of sex-linked genes is due to a difference in the structure of the X-chromosomes of males and females. This difference is also demonstrated by the fact that a male X-chromosome binds twice as many molecules of 3H-labelled RNA polymerase as does each of the female X-chromosomes. The difference in the in vitro template activities of male and female X-chromosomes cannot be overcome by pretreating them with deoxyribonuclease S1 specific for single-stranded DNA which implies that single-stranded regions are not important for the phenomenon of dosage compensation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332514
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  • 2
    Electronic Resource
    Electronic Resource
    Binding of thymus histone F1 and E. coli RNA polymerase to DNA of Polytene Chromosomes of Drosophila (1973)
    Springer
    Chromosoma 44 (1973), S. 255-264 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Polytene chromosomes of Drosophila melanogaster can bind large quantities of calf thymus histone F1 and E. coli RNA polymerase. This shows that a substantial fraction of chromosomal DNA is accessible for interaction with extra-chromosomal proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00291020
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  • 3
    Electronic Resource
    Electronic Resource
    Comparison of in vivo and in vitro RNA synthesis on polytene chromosomes of Drosophila (1976)
    Springer
    Chromosoma 54 (1976), S. 349-362 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A comparative radioautographic study of the RNA precursors incorporation on polytene chromosomes of Drosophila in vivo in the cells of salivary glands, and in vitro during incubation of E. coli RNA polymerase on slides with fixed chromosomes was performed. — The pattern of in vivo 3H-uridine incorporation on different sections of the chromosomes drastically differed from the in vitro 3H-UTP incorporation which seems to be much more related to DNA content of the individual small sections. In both cases puffing of the loci resulted in the increase of RNA synthesis but in vitro only 2–3 fold and in vivo much more. Hence, RNA synthesis in vitro was unspecific and did not reflect the in vivo RNA synthesis. — On the other hand, E.coli RNA polymerase completely mimics in vitro the dosage compensation phenomenon making twice as much RNA on one X-chromosome of males (1X2A) as on each of X-chromosomes of diploid (2X2A) and triploid (3X3A) females and super-females (3X2A), and the intermediate amount of RNA on each of X-chromosomes of intersexes (2X3A). It is suggested that the differences in the in vitro template activity of X-chromosomes of cells with different X∶A ratio are due to different extent of condensation of their deoxyribonucleoprotein (DNP). Yet, both male and each of female X-chromosomes bind the same amount of thymus histone FI labelled with fluorochrome which indicates that they contain the same amount of “open” regions with exposedchromosomal DNA accessible to external proteins. — On the basis of these observations a hypothesis is put forward which suggests that RNA transcription in animal chromosomes is regulated at two levels by different mechanisms; the first one controls the extent of condensation of DNP of genetic loci and determines their competence to the second mechanism which involves the action of gene-specific activator proteins. According to this hypothesis the phenomenon of dosage compensation of sex-linked genes is due to decondensation of DNP of male X-chromosome which renders its loci twice as responsive to activators as compared to the same loci in females.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292815
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of deficiency of the histone gene-containing 38B-40 region on X-chromosome template activity and the White gene position effect variegation in Drosophila melanogaster (1978)
    Springer
    Molecular genetics and genomics 162 (1978), S. 323-328 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The deficiency of the 38B-40 region containing histone genes in one of the 2nd chromosomes of D. melanogaster triploid intersexes increases the template activity of X-chromosomes both in vivo and in vitro without noticeably affecting autosome activity. This deficiency in the heterozygous state inhibits the variegated position effect of the white gene in the T(1;3)w vcotranslocation in diploid females and males, but not affect their rate of development. The variegation suppressor Su(var)hg-1 not only suppress the gene position effect in diploid flies, but also increases the template activity of X-chromosomes in triploid intersexes. The results are discussed with respect to the dependence of gene activity on the structure of chromosomes (density of DNP packing).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00268858
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  • 5
    Electronic Resource
    Electronic Resource
    Primary structure of Escherichia coli RNA polymerase nucleotide substitution in the β subunit gene of the rifampicin resistant rpoB255 mutant (1981)
    Springer
    Molecular genetics and genomics 184 (1981), S. 536-538 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transducing phage λ dsupM814 and the plasmid pIB1830 containing the wild-type rpoB gene have been constructed and the primary structure of the gene's central fragment has been established. In contrast with the wild-type, the gene of the rpoB255 mutant, whose primary structure has been published, was found to contain an A.T.→T.A. transversion entailing the substitution of a valine residue for the aspartic acid residue (516) of the wild-type β subunit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00352535
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  • 6
    Electronic Resource
    Electronic Resource
    Telomeres and P-element of Drosophila melanogaster contain sequences that replicate autonomously in Saccharomyces cerevisiae (1984)
    Springer
    Molecular genetics and genomics 197 (1984), S. 342-344 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have isolated restriction fragments from a “shotgun” collection of Drosophila DNA which function as autonomously replicating sequences (ARS) in Saccharomyces cerevisiae and hybridize with telomeric regions of the 2L, 2R, 4, and X chromosomes. In an independently obtained set of D. melanogaster clones five fragments hybridize in situ with telomeres and a number of internal sites. Two of them also contain ARSs. A Drosophila mobile P-element also possesses ARS activity in yeast.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330983
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  • 7
    Electronic Resource
    Electronic Resource
    Maternal influence upon the V-type gene position effect in Drosophila melanogaster (1978)
    Springer
    Molecular genetics and genomics 163 (1978), S. 327-334 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have studied the influence of various factors on the V-type position effect of the white gene transposed to heterochromatin as a result of different chromosome rearraugements in D. melanogaster. Variegation due to the white gene position effect is much weaker if the flies have received Dp(1;3)wvco from parental males, and not females. The origin of the chromosome rearrangement does not have this influence in the case of T(1;4)wm5 or has it to insignificant extent in the case of In(1)wm4. The Y-chromosome in maternal genome strongly suppresses Dp(1;3)wvco-induced variegation even in the progeny which has not received an extra Y-chromosome but only if this progeny gets Dp(1;3)wvco from the same female. The low temperature (16° C) at which parental females have developed, considerably affects the position effect in the progeny with Dp(1;3)wvco, whereas the temperature of males' development has no influence at all. The maternal temperature effect occurs also when Dp(1;3)wvco has come down from the father, though it is stronger if the mother subjected to low temperature treatment bore the rearrangement. The influence of temperature seems to take effect at the final stages of oogenesis. The data obtained lead one to suppose that the influence of genotypic and external factors on variegation is passed to the next generation of flies in different ways. The direction of crosses and additional Y-chromosome heterochromatin in the maternal genome seem to affect variegation in the progeny through changes in the properties (structure) of the chromosome rearrangement expressing the position effect. As to the temperature of the mothers development, only a small part of its influence may be accounted for by the same mechanism, whereas most of the temperature influence seems to be passed on through other components of the nucleus or through the cytoplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271962
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  • 8
    Electronic Resource
    Electronic Resource
    Mercury-resistant plasmids in bacteria from a mercury and antimony deposit area (1984)
    Springer
    Molecular genetics and genomics 197 (1984), S. 280-285 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Most bacterial cells (Pseudomonas, Acinetobacter) obtained from the soil at the Khaidarkan mercury and antimony mine (Kirghiz USSR) contain R plasmids with mercury (HgCl2) resistance determinants. The plasmids have a large molecular mass (about 100 MD, though smaller ones also occur), and at least some of them are transmissive. Many of the Hgr bacteria also display an elevated antimony (SbCl3) resistance, though this trait was not shown to be plasmid-dependent. There are practically no Hgr plasmids in bacteria taken from the soil at different distances from the mine: the saturation of bacteria with Hgr plasmids is maintained by selective pressure only in the area with a high enough toxin concentration. In the same mercury and antimony deposit area Hgr plasmids were also found in Escherichia coli isolates from the gut of Mus musculus mice and Bufo viridis toads. At least some of the bacterial plasmids obtained from animals also carry antibiotic-resistance determinants (Tcr, Cmr, Smr). These plasmids are also transmissive. They display internal instability and lose their resistance determinants after a conjugation transfer to other E. coli trains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330974
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  • 9
    Electronic Resource
    Electronic Resource
    Competition for the DNA template between RNA polymerase molecules from normal and phage-infected E. coli (1972)
    Springer
    Molecular genetics and genomics 119 (1972), S. 299-314 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Preincubation of E. coli core RNA polymerase lacking sigma-factor with limiting amounts of T2-DNA markedly decreases subsequent synthesis of RNA by RNA polymerase holoenzyme. Hence, although the core binds to DNA more weakly than does the holoenzyme, it can actively compete with RNA polymerase for the DNA template. Both core RNA polymerase and holoenzyme from uninfected bacteria are effective in competition with RNA polymerase isolated from T2-infected cells. On the other hand the enzyme obtained from T2-infected cells compete weakly with RNA polymerase from E. coli. The incubation of bacterial core-enzyme with a supernatant protein fraction obtained from phage-infected bacteria lowers its ability to compete with normal RNA polymerase for DNA template. These results are discussed from the viewpoint that in certain cases the RNA polymerase itself can act as a kind of repressor, effecting negative regulation of RNA synthesis. The modification of core and formation of anti-sigma induced by bacteriophage could participate in such kind of regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00272088
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  • 10
    Electronic Resource
    Electronic Resource
    A nonconjugative mobilizable broad host range plasmid of Acinetobacter sp. that determines HgCl2 resistance (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 286-290 
    Details
    ISSN: 1617-4623
    Keywords: Acinetobacter ; HgCl2 resistance ; pKL1 ; Conjugational transfer ; Replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary HgCl2-resistant strains of Acinetobacter sp. obtained from the soil at the Khaidarkan mercury mine (Kirghiz SSR) were found to contain, apart from large plasmids (∼60 kb), a small plasmid (∼7.5 kb) designated pKL1. It was established by conjugative crosses and transformation that pKL1 is a broad host range mobilizable plasmid and that it carries the Hgr determinant. The restriction map of pKL1 was constructed; the site of the Hgr determinant and the regions essential to replication were localized. A comparison of these results with earlier data suggests that microorganisms belonging to one microbiocenosis may carry Hgr determinants on plasmids with highly different structures and properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331652
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