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Biomedical subjects

A A Baev

Publications and source records attributed to A A Baev.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Structure of long terminal repeats of transcriptionally active and inactive copies of the mobile dispersed gene MDG3 in Drosophila melanogaster].

The nucleotide sequences of long terminal repeats (LTRs) and adjacent regions are determined in the transcribed and non-transcribed variants of a mobile dispersed genetic element MDG3. MDG3 is similar to other mdg elements. A 4 bp duplication of the host DNA is generated upon its integration. MDG3 is flanked by a 5 bp inverted repeat. The length of the LTRs varies in different MDG3 variants, the difference being connected mainly with duplications of certain sequences in U3 and R regions. The copies with 267 bp LTR are the most abundant ones and perfectly conservative in their primary structure. They are transcribed in 67J25D cell culture and are not transcribed in Kc cell line, where another variant with LTR length 293 bp is transcriptionally active. S1-mapping of transcription initiation and termination sites has demonstrated that in both MDG3 variants they are situated in the same positions, and the LTR itself may be subdivided into U3, R and U5 regions, like retroviral LTRs. Possible factors involved in the regulation of mdg transcription are discussed.

Animals↗
PubMed1982

[Distribution of 5-methylcytosine in phage lambda genome methylated by DNA methylase Eco RII].

The distribution of 5-methylcytosine in Eco RI-Bam HI fragments of phage lambda DNA in vitro methylated by Eco RII methylase has been studied. The general picture of distribution of methylated sites in phage lambda DNA is slightly different from the statistical distribution. However, the sites have been found, where the distribution of 5-methylcytosine is not accidental. A complete absence of 5-methylcytosine in the J-fragment, a genome lambda area essential for site-specific recombination, has been found. The absence of Eco RII is supposed to be the best protection of this area of phage genome from the increased mutagenesis, characteristic for nucleotide sequences methylated by DNA-methylated Eco RII and Eco RII type.

5-Methylcytosine↗
PubMed1982

[Isolation, purification and properties of restriction endonuclease EcoRII].

The restriction endonuclease Eco RII was isolated and purified to homogeneity. The isolation procedure involved the use of the E. coli strain B834/pSK323, containing the recombinant plasmide pSK323 which provides for the oversynthesis of Eco RII enzymes. Data from gel filtration and Na-DS electrophoresis suggest that the restriction endonuclease Eco RII is a protein made up of two subunits, each with molecular weight of 44 000.

DNA Restriction Enzymes↗
PubMed1982

[Use of DNA-methylases as reagents for the production of isotopically labeled DNAs].

The method of incorporation of an isotopic label into DNA by means of DNA-methyltransferases (DNA-methylases) is proposed. DNA was no degraded and retained its biological activity in the DNA-methylase reaction. The specific activity of labelled DNA preparations can be increased, using the mixtures of different DNA-methylases in the enzymatic reaction. An isotopic label was incorporated into DNA, using DNA methylases M. .EcoRII, M.Eco dam and M.EcoMRE600 dcmI. An average activity of 1 microgram of labelled DNA preparations produced by S-adenosylmethionine (methyl-3H) with specific activity of 15 CU/mmol mas about 1 x 10(5) cpm.

DNA↗