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Biomedical subjects

E F Loseva

Publications and source records attributed to E F Loseva.

7 recordsLinked to original sources
PubMed2000

[Cloning of a new murine gene coding for a protein immunologically related to RecA protein from Escherichia coli].

Using the testis-specific murine cDNA library immunoscreening with the affine-purified polyclonal antibodies to the E. coli RecA protein, the 1730-bp fragment of the novel mouse gene was cloned. Northern hybridization of total RNA samples from mouse somatic and meiotic tissues showed that this gene was specifically expressed in mouse testis, producing a transcript of about 10 kb in size. Analysis of the cloned cDNA sequence revealed the presence of the-AATAAA-polyadenylation site at its end, indicating that the cloned fragment represented the end part of the corresponding gene. Comparative sequence analysis revealed that the plus-chain of the cloned fragment contained motifs of the mouse RAD50 gene; the 378-bp fragment of the minus-chain showed 96% homology with the Homo sapiens Hd741-f cDNA fragment; and the whole minus-chain was by 50% homologous to the prokaryotic FTSZ/A genes. The cloned fragment contained two reading frames located in the plus- and minus-chains, respectively. The presumptive 44-kDa protein encoded by the plus-chain (sense) open reading frame contained serine-, proline-, and threonine-rich regions and was 25 to 30% homologous to a number of nuclear DNA-binding proteins of eukaryotes. Although analysis of the similarity between the 44-kDa protein and the E. coli RecA protein did not show any significant homology between them, it revealed their identity by five amino-acid residues involved in the formation of the epitope that recognized the paratope of the RecA protein antibody for subsequent epitope-paratope binding of these proteins.

Animals↗
PubMed2000

[Localization of proteins, immunologically similar to Eschericha coli RecA protein, in structures of cultured cells of HeLa and K-562 cell lines].

Earlier, polyclonal antibodies to the Escherichia coli RecA protein revealed immunologically related proteins only in the reproductive tissues of various eukaryotes and the proteins were localized to the various structures of the synaptonemal complex (SC). Indirect immunofluorescent FITC staining with polyclonal antibodies against RecA detected RecA-like antigens in the cell center (centrosome) and the replicated centrioles of fixed HeLa and K-562 cells. Human and mouse genes, which were previously cloned by immunological relatedness of their products to E. coli RecA, were used as hybridization probes in Northern blot analysis of the transcription activity of similar genes in K-562 cells. A gene homologous to the cloned mouse gene proved transcribed in the cells studied.

Animals↗
PubMed1999

[Cloning and determination of the structure of a new human gene, homologous to Saccharomyces cerevisiae rad proteins].

Cloning of a novel Homo sapiens gene from cDNA libraries of human testes using immunoscreening procedure with affinity-purified polyclonal antibodies against E. coli RecA protein was carried out. The nucleotide sequence and chromosomal localization of this gene were determined. Computer modeling of its primary transcript was conducted. The gene investigated is localized on the P arm of chromosome 19 within the 19p13.1 cluster and consists of seven exons and six introns. It has a leader, 3' untranslated, and translated regions. The translated sequence encodes a 33-kD protein that displays 30-40% homology to the Saccharomyces cerevisae Rad proteins. TATA- and CAAT-like sequences are situated at positions -30 and -40 bp as well as -102 and -148, respectively. The absence of CCGCCC- or GGGCGG-like sequences may indicate that this gene is tissue-specific.

Amino Acid Sequence↗
PubMed1996

[Localization of RecA-like proteins in preparations of spread nuclei of mouse spermatocytes at meiotic prophase I].

Earlier, polyclonal antibodies to Escherichia coli RecA protein were used to identify immunologically related proteins in meiotic spermatocytes of different eukaryotes. At least one such protein proved to be a component of the synaptonemal complex (SC) [1]. Subsequent experiments on localization of RecA-like antigens in SCs of spermatocytes were performed by indirect immunocytochemical methods and electron microscopy, which showed that RecA-like protein(s) at early leptotene are largely associated with chromatin. During SC formation (at leptotene and zygotene), they are found in both lateral elements and the central space of SC. In some cases, RecA-like proteins are associated with SC substructures that resemble recombination nodules. When spermatocytes enter late diplotene, Rec-A-like proteins cease to be detected in SC structures.

Animals↗
PubMed1993

[Antibodies against Escherichia coli RecA protein reveal two nuclear proteins in bovine spermatocytes which interact with synaptonemal complex structures of meiotic chromosomes of various eukaryotic organisms].

Three RecA-like proteins were detected in bovine meiotic cells using antibodies against Escherichia coli RecA protein. After isolation and purification of these RecA-like proteins their molecular weights appeared to be equal to 37, 70 and 130 kD. The 37 kD protein accompanies all the stages of spermatogenesis up to the stage of mature spermatozoa. The 70 kD protein is detectable only in nuclei of cells at the stage of prophase I of meiotic division. These RecA-like proteins are involved in the formation of structural elements of the synaptonemal complex (SC) and are detected in the SC composition in meiotic cells not only of mammals but also of plants and insects, which suggests the evolutionary conservative character of these proteins.

Animals↗
PubMed1991

[Cloning the alpha-amylase gene of Streptococcus bovis and its expression in Bacillus subtilis cells].

The gene coding for alpha-amylase from the ruminant bacterium Streptococcus bovis was cloned on the plasmid pMX39 in Bacillus subtilis cells. An alpha-amylase positive colony was isolated in the initial screening of 3900 colonies on the medium containing insoluble starch. The size of the insert was approximately 2.8 kb. The recombinant plasmid was stably maintained in Bacillus subtilis cells under the nonselective conditions.

Bacillus subtilis↗