[Current trends in the use of DNA technologies]. / Sovremennye napravleniia ispol'zovaniia DNK-tekhnologii.

The possibilities of the intra- and interspecies genetic polymorphism revealing in animals with the uses of RAPD-PCR are discussed. The polymorphism of microsatellite loci and its using for the evaluation of the population-genetic interrelations is examined. The perspectives of the revealing of the genetic disease carriers at the cattle with the use of DNA methods are presented. The problems of gene transfer in farm animals are discussed. Data on the transgenic plant-based vaccine development against human and animal diarrhea diseases are analyzed.

[Cloning of tobacco DNA fragment with promoter properties in a transgenic plant]. / Klonirovanie fragmenta DNK tabaka, obladaiushchego svoistvami promotora v transgennom rastenii.

A selection system for isolating DNA sequences with transcription-promoting activity by their functioning in bacterial cells has been proposed. Tobacco nuclear DNA fragments were inserted in front of the promoterless neomycin 3'-phosphotransferase II (NPT-II) gene and promoter-like sequences were identified by their ability to restore NTP-II activity in E. coli cells. One of these recombinant plasmids was introduced in tobacco protoplasts by direct gene transfer and transformed calli were isolated by kanamycin selection. The NTP-II expression in regenerated transgenic plants were highest in root, slightly lower in stem and were practically absent in leaf. Sequence analysis of cloned segment showed the presence of conserved sequences essential for promoter activity in eukaryotic cells. A transcription start site was observed by S1 mapping. The size of protected fragments corresponds to the initiation of transcription 176 and 179 base pairs upstream the initiation codon in tobacco and 75 base pairs in E. coli.

[Isolation of a biologically active poly(A)+RNA from tissues enriched with polysaccharides]. / Poluchenie biologicheski aktivnoi poli(A)+RNK iz tkanei, obogashchennykh polisakharidami.

A special technique is developed for isolation of biologically functional poly(A)+RNA from higher plant cells to start with some procedures used to isolate RNA of the eucaryote cells. The technique includes cell disruption with a 4 M guanidine thiocyanate solution, hot phenol extraction of RNA following proteinase K digestion and methoxyethanol treatment to remove polysaccharides. Finally, poly(A)+RNA was purified by oligo(dT)-cellulose chromatography. Using this technique poly(A)+RNA preparations were obtained from French bean embryo axis, maize and sugar beet seedings, potato tubers and seedlings. It is shown that poly(A)+RNA isolated from the plant cells directs protein synthesis in the cell-free system. This RNA may be also used as a matrix for synthesis of cDNA in the reverse transcription reaction.

[Splitting of mononucleosomes into histone-containing subnucleosomes]. / Rasshcheplenie mononukleosom na gistonsoderzhashchie subnukleosomy.

Histone-containing subnucleosomal particles SN7 and SN4 revealed initially in micrococcal nuclease digest of mouse chromatin were studied. It was found that production of SN7 and SN4 did not depend on the preservation of supranucleosomal levels of chromatin organization and was the result of intranucleosomal splitting. Micrococcal nuclease that preferentially attacks internucleosomal linker DNA can cut mononucleosomes with the formation of 40 b. p. DNA fragment complexed with H2a and H2b and SN7 particle containing six histones (H2a, H2b, 2H3 and 2H4) and 108 b. p. DNA. It is proposed that such a splitting of nucleosomes reflects their intimate organization, particularly a histone-DNA interaction within core particles. These results are interpreted in terms of a nucleosomal model in which H2a-H2b pairs are localized in the peripheral parts of the nucleosomal DNA superhelix.

[Studies of histone-nonhistone complex]. / Issledovanie kompleksa gistony - negistonovye belki.

A chromatin protein complex was isolated from the calf thymus using hydroxyapatite without denaturants. Polyacrylamide gel electrophoresis showed that this complex consisted of five histones and nonhistone proteins. The complex is stable in 2 M sodium chloride. As the evidence of its stability the results are presented or rechromatography on hydroxyapatite, of gel-filtration on Sephadex G-150 and of polyacrylamide gel electrophoresis after crosslinking proteins by formaldehyde under mild conditions. It is suggested, that hydrophobic interactions which take place under high ionic strength due to the counteraction of protein charged groups, are among the possible mechanisms. This is supported by partial dissociation of the complex with a decrease in the sodium chloride concentrations in the solution.