Publications by authors named "Kraevskiĭ V"

Structural rearrangements of chromatin resulting from changes in axial twisting of internucleosomal linkers were studied using the intercalators of ethidium bromide and chloroquine diphosphate. It was determined how the modifications of the primary structure affect the compactization of chromatin fibrils. The data obtained suggest that changes in the relative angle of rotation between nucleosomes result in changes in the spatial organization of chromatin fibrils.

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The effect of hyperacetylation of histones on the packing of nucleosomal fibers into higher-order structures was studied. The organization of the higher-order levels of packing of hyperacetylated and normal chromatin in intact hepatocytes of green marmoset (CV1 line) was compared by using the intercalating agent chloroquine diphosphate to change the axial twinting of DNA of internucleosomal linkers.

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Recent data on chromatin structural organization are presented. In the light of present concept of chromatin structure the problem of hierarchical levels of DNA packaging within chromatin is discussed. Particular emphasis has been placed on the correlation between the changes occurring at different DNA compactization levels within topological domains and chromatin functional activity.

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Influence of specific nucleotide sequences on the constitutive transcriptional activity of the Rous sarcoma long terminal repeats (LTR) was studied. The possible function of different elements of the transcriptional control region of the avian retroviral LTR was discussed on the basis of a comparative analysis of the effect of specific nucleotide insertions on LTR activity in vivo and in vitro.

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Conformational mobility of 30 nm nucleosomal fiber under temperature variations at different ionic strength of the medium has been analyzed. A new property of chromatin organization has been characterized, namely, nucleosomal solenoid condensation in response to increase of temperature. This property is analogous to salt-induced condensation and becomes particularly prominent at low ionic strength.

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It has been discovered that chemical acetylation of chromatin in vitro by acetyladenylate leads to decrease in the mobility of nucleosomal fiber fragments in agarose gel. Acetylation of HI-depleted chromatin does not produce this effect. Based on these results together with other available data, it is possible to conclude that acetylation causes decompactization of the chromatin fiber.

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A method was proposed for analysis of conformational mobility of supranucleosomal chromatin organization at different ionic conditions with the help of electrophoresis in low-density agarose gels. This simple and highly reproducible method yields the results which are in good agreement with the data of other traditional approaches. This method offers an alternative to high-speed ultracentrifugation for chromatin condensation studies.

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An attempt is made to estimate the degree of conformational flexibility of DNA in different fractions of nucleosomes of transcriptionally active chromatin of higher eukaryotes, and in yeast nucleosomes as well. We have used the circular dichroism method to estimate conformational changes in DNA induced by temperature shift. The DNA conformational potential was shown to be approximately the same in all the fractions of nucleosomes under study.

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The distribution of specific DNA sequence elements in a 2.9 kb HindIII fragment of chicken DNA containing the replication origin and the upstream matrix attachment site of the alpha-globin gene domain has been studied. The fragment was shown to contain the CR1-type repetitive element and two stable bent DNA sequences.

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The importance of spatial organization of DNA for the regulation of genome activity is discussed. The main problem reviewed in this paper includes cooperative interactions of proteins with DNA, formation of DNA loops in the regulatory domains of the genome and conformational mobility of DNA in chromatin.

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