[Design of an expression vector for delivery of in vivo recombinant biologically active proteins. 1. Synthesis of the antigenic determinant of HIV-1 gp120 and gp41 proteins in enterobacteria]. / Konstruirovanie ékspressionnogo plazmidnogo vektora dlia osushchestvleniia dostavki in vivo rekombinantnykh biologicheski aktivnykh belkov. 1. Sintez antigennykh determinant belkov gp120 i gp41 VICh-1 v énterobakteriiakh.

High-level expression vector pAZ was constructed for in vivo delivery of bioactive recombinant proteins, antigenic determinants, among other things. This vector meets the requirements to construction of recombinant bacteria as live oral carriers. It has a strong constitutive promoter, high stability in E.coli and vaccine strain Salmonella cells, and, moreover, encodes in addition for the marker protein (beta-galactosidase) which will later help follow up the fate of bacterial carriers and their interactions in the microorganism. Several recombinant plasmids encoding for beta-galactosidase variants with insertions of short fragments of HIV-1 gp41 and gp120 proteins, which were previously shown to be antigenic determinants, have been constructed on the basis of pAZ. E.coli and vaccine strain Salmonella cells were transformed by recombinant plasmids. To a considerable extent the level of hybrid protein synthesis depends on the structure of the antigenic determinant inserted. The maximal level of synthesis in E.coli is 16%. This hybrid protein could be isolated and purified (up to 90%) with the yield of 4 to 6 mg/g of wet cells. Almost all the hybrid proteins were immunologically reactive, as shown by ELISA with nonfractionated lysates and purified hybrids. In both strains in vitro stability of the vector and recombinant plasmids was at least 90% after 10 passages (about 140 generations) under random conditions. This paper sums up the first stage of construction of recombinant bacteria as live oral carriers.

[Study of the mutagenic properties of oligonucleotides containing and internucleotide pyrophosphate bond using a mutation system based on phage M13]. / Issledovanie mutagennykh svoistv oligonukleotidov, soderzhashchikh mezhnukleotidnoe pirofosfatnoe zveno, c pomoshch'iu mutatsionnoi sistemy na osnove faga M13.

Mutagenic properties of oligonucleotides with pyrophosphate internucleotide bond was studied. It was shown that the pyrophosphate bond in the oligo structure does not induce mutations but promotes a more efficient induction of marker deletions predetermined by the nucleotide sequence as compared to the native oligonucleotide. Marker deletion induction proceeds according to the repair mechanism as homozygotes dominate in the mutant generation.

[Mutagenesis, directed by artificial oligonucleotide analogs. I. Participation of ribonucleotide fragments in DNA replication and repair]. / Mutagenez, napravlennyi neprirodnymi analogami oligonukleotidov. I. Uchastie ribonukleotidnykh zven'ev v reparatsii i replikatsii DNK.

The mutation system has been developed to study the mutagenic properties of modified oligonucleotide analogs. The mutagenic properties of oligonucleotides containing one ribonucleotide have been examined. The presence of a ribonucleotide is shown not to induce any mutations. But when the oligonucleotide induces two marker deletions detached by 6 nucleotides they may be repaired separately, in this case the deletion bordering with the ribonucleotide is predominantly repaired.

[Study of the mechanism of mutagenesis directed by phosphotriester analogs of oligonucleotides. The role of repair in mutagenesis]. / Issledovanie mekhanizmov mutageneza, napravlennogo fosfotriéfirnymi analogami oligonukleotidov. Rol' reparatsii v zakreplenii mutatsii.

The mutation system has been suggested in an effort to test insertion and deletion mutants by changing the Lac-phenotype of bacterial colonies transformed by mutant DNA. This system also makes possible to determine heterozygotes and homozygotes among the mutants. The yield of mutants in shown to depend on the structure of the DNA heteroduplex region. The yield of deletion mutants is greater than that of insertion mutants. Heterozygotes prevail in mutant colonies (greater than 90%).