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O V Preobrazhenskaya

Publications and source records attributed to O V Preobrazhenskaya.

8 recordsLinked to original sources
PubMed1993

Two non-histone proteins are associated with the promoter region and histone HI with the transcribed region of active hsp-70 genes as revealed by UV-induced DNA-protein crosslinking in vivo.

We described here an approach for mapping proteins on any sequence of genomic DNA. UV-induced DNA-protein crosslinking within whole cells and the 'protein image' hybridization technique (1) were applied to test the proteins bound to different regions of the D. melanogaster hsp-70 gene. The histone H1-DNA association with the coding region is shown to be maintained, even during very intensive transcription, but is absent in the promoter. Two non-histone proteins with apparent molecular masses of 50 kD (p50) and 100 kD (p100) are crosslinked only to the active hsp-70 gene regulatory region and preferentially bind to its complementary and coding DNA strands, respectively.

Animals↗
PubMed1990

Chromatin structure of Drosophila melanogaster ribosomal genes.

The chromatin structure of ribosomal genes of D. melanogaster has been studied by crosslinking proteins to DNA. We found that a number of histone contacts with DNA through histidine in the approximately 1 kb-long region surrounding the transcription initiation site, coding regions and the region of 240 bp-long repeats from the intergenic spacers (Alu-repeats) were weakened as compared to the inactive chromatin of the type II insertion. A protein with the molecular mass of 50 kDa (p50), associated with all DNA sequences analysed, has been discovered. Another protein with molecular mass of about 70 kDa (p70) has been found to be specific only for the Alu-repeats.

Animals↗
PubMed1989

Change in the pattern of histone binding to DNA upon transcriptional activation.

Patterns of histone binding to DNA of transcriptionally active D. melanogaster hsp70 genes within the nuclei have been analyzed by two methods of histone-DNA chemical cross-linking. When cross-linking is restricted to the central, "globular" regions of histones, it drops most for H1, to an intermediate extent for H2A and H2B, and least for H3 and H4 in transcriptionally active versus transcriptionally silent chromatin. When it occurs via histone terminal regions as well, cross-linking is quantitatively similar for active and inactive chromatin. Neither cross-linking method detects histones on the hsp70 promoter region. It appears that chromatin activation decreases histone binding to DNA via the "globular" regions, known to be essential for the folding of nucleosomes and the 30 nm chromatin fibril, but does not significantly affect the interaction of flexible and loosely bound histone "tails" with DNA. The role of these histone-DNA interaction changes in the unfolding of active chromatin and RNA polymerase reading through histone-bound DNA is discussed.

Animals↗
PubMed1984

Chromatin structure of hsp 70 genes, activated by heat shock: selective removal of histones from the coding region and their absence from the 5' region.

The presence of histones in hsp 70 genes was studied by "protein-image" hybridization technique after crosslinking histones to DNA. With increasing transcription of the genes, the coding region was demonstrated to be depleted first of H1 and then of all histones. This probably accounts for unraveling the 25 nm silent chromatin fiber to moderately and actively transcribed 10 nm fiber and linearized DNA. No histones were found in the 5'-terminal DNAase I-hypersensitive region, which may be a prerequisite to gene activation. The absence of histones on DNA correlates well with the high nuclease sensitivity and disappearance of the regular pattern in micrococcal nuclease digests of chromatin.

Animals↗
PubMed1982

Alignment of nucleosomes along DNA and organization of spacer DNA in Drosophila chromatin.

A series of mono- and dinucleosomal DNAs characterized by an about ten-base periodicity in the size were revealed in the micrococcal nuclease digests of Drosophila chromatin which have 180 +/- 5 base pair (bp) nucleosomal repeat. 20, 30, and 40 bp spacers were found to be predominant in chromatin by trimming DNA in dinucleosomes to the core position. Among several identified mononucleosomes (MN), MN170, MN180 and MN190 were isolated from different sources (the figures indicate the DNA length in bp). The presence of the 10, 20, and 30 bp long spacers was shown in these mononucleosomes by crosslinking experiments. The interaction of histone H3 with the spacer in the Drosophila MN180 particle was also shown by the crosslinking /5/. We conclude from these results that the 10 n bp long intercore DNA (n = 2, 3 and 4) is organized by histone H3, in particular, and together with the core DNA forms a continuous superhelix. Taken together, these data suggest that Drosophila chromatin consists of the regularly aligned and tightly packed MN180, as a repeating unit, containing 10 and 20 bp spacers at the ends of 180 bp DNA. Within the asymmetric and randomly oriented in chromatin MN180, the cores occupy two alternative positions spaced by 10 bp.

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