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O I Karpova

Publications and source records attributed to O I Karpova.

8 recordsLinked to original sources
PubMed1993

[A preparative method for isolating the synaptonemal complexes from mammalian spermatocytes].

A method of isolation of synaptonemal complexes (SC) from mouse, rat and Syrian hamster spermatocytes is described. A fraction of pachytene spermatocyte nuclei was obtained by centrifugation of the testis homogenate in stepwise sucrose gradient and then lysed. The resulting chromatine was hydrolysed with DNAse II, and a fraction of isolated SCs was obtained by ultracentrifugation of the hydrolysate. The method can be applied for obtaining the SC fraction from spermatocytes sufficient for cytological, biochemical and molecular biology studies.

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[Synaptonemal complex proteins: specific proteins of meiotic chromosomes].

The review considers proteins of the synaptonemal complex (SC), a specific structure formed between homologous chromosomes in maturing germline cells during meiotic prophase I. The structure and functions are described for proteins that form ultrastructural SC elements in mammals, in yeast, and in higher plants. The roles of cohesions and of the SC proteins in meiotic sister-chromatid cohesion are considered. Though still scarce, data are summarized on the SC self-assembly and dissociation and on the molecular composition of SC-associated recombination nodules, which provide a compartment for meiotic recombination enzymes. The accumulating data on the SC molecular components and on their structure, properties, and interactions improve the understanding of the SC function.

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[Localization of DNA sequences tightly associated with synaptonemal complex in compositional fractions of golden hamster].

The synaptonemal complex isolated from the spermatocyte nuclei by exhaustive hydrolysis of the latter by DNase II contains tightly associated DNA sequences (SCAR DNA). Here we studied the compositional properties of a cloned family of SCAR DNA of golden hamster, namely we performed the localization of 27 SCAR DNA clones on compositionally fractionated genomic DNA from golden hamster. We observed that sequences of the SCAR DNA family are mainly localized in the GC-poor isochore families L1 and L2, that showed 63% hybridization signals. This means that 37% of signals is referred to the GC-rich isochores, indicating the presence of SCAR DNA overall the genome, even if each isochore family presents differences in density and sequence type. Moreover, the SCAR DNA sequences containing regions of homology with LINE/SINE repeats were observed in all the isochore families. The compositional localization of SCAR DNA is in agreement with the hypothesis that SC and SCAR DNA participate in the chromatin organization during the meiosis prophase I, which should result in the attachment of chromatin loops to lateral elements of SC along the whole length of the latter.

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PubMedDate not supplied

[Various properties of DNA from isolated fractions of the mouse synaptonemal complexes].

A fraction of synaptonemal complexes (SC) isolated from mouse spermatocytes has been electrophoretically purified in agarose gel. The DNA from the SC fraction constitutes approximately 0.5% of total nuclear DNA, and its molecules have length heterogeneity from 1 k.b. to 20 k.b. The content of beta-globin gene is the same in DNA from the SC fraction and in total nuclear DNA. The specificity of DNA from the SC fraction is manifested by higher contents of the repeated alternative sequences GT/CA and B1-sequence that is probably due to the processes of genetic meiotic recombination.

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PubMedDate not supplied

[Features of the primary structure of DNA from the synaptonemal complex of the golden hamster].

DNA of golden hamster synaptonemal complex (SC) was cloned and partially sequenced. Computer analysis was performed to compare the SC DNA sequences for different families of eukaryotic genomic DNA. SC DNA is homologous to LINE family and in contrast to genomic DNA is enriched with alternative (GT/CA)n sequences and palindromes. By its ability to form potential hairpin loops, SC DNA is similar to nuclear matrix-associated regions of DNA (MARs) and differs considerably from DNA of microsatellite loci. It is noteworthy that SC DNA, which is supposed to be involved in meiotic recombination, and DNA of immunoglobulin genes, involved in somatic recombination, are both enriched with palindromes. The discovered peculiarities of the structure of hamster SC DNA allow us to join it with rat SC DNA into a special family of rodent genomic DNA sequences.

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