[Insulators and interaction between long-distance regulatory elements in higher eukaryotes]. / Insuliatory i vzaimodeistvie mezhdu reguliatornymi élementami na bol;shikh distantsiiakh u vysshikh éukariot.

Enhancers can activate a promoter located as far as several hundred kilobases away, which is specific for transcription regulation in higher eukaryotes. Notwithstanding the vast information accumulated on transcription regulation at various levels, the mechanism of long-distance enhancer-promoter interactions is still obscure. Modern views of insulators as elements modulating enhancer-promoter interactions are reviewed.

[Role of the "enhancer of yellow" genes in the regulation of expression of the "yellow" gene in Drosophila melanogaster]. / Rol' genov "enhancer of yellow" v reguliatsii ékspressii gena "yellow" u Drosophila melanogaster.

The e(y)1/TAFII40, e(y)2 and e(y)3 genes encode general transcription factors in Drosophila melanogaster. Weak mutations in e(y)1u1, e(y)2u1 and e(y)3u1 regulate enhancer-dependent transcription of the yellow gene in bristles similarly, even if it is activated by a non-yellow specific enhancer element. At the same time, these mutations do not affect yellow expression in the body and wings. We found genetic data indicating that the e(y) proteins support the promoter/bristle enhancer interaction. Futhermore, the su(Hw) insulator properties change in the presence of e(y)1u1, e(y)2u1 and e(y)3u1 mutations. When introduced at +2490 from the transcription initiation site, the su(Hw) insulator becomes able to block interactions between the bristle enhancer and yellow promoter, not separating them from each other.

[Mechanisms of excising the P-element in a model system at the yellow locus of Drosophila melanogaster]. / Izuchenie mekhanizmov vyrezaniia P-élementa na model'noi v lokuse yellow u Drosophila melanogaster]

Patterns of excision of a single P element were studied in a model system of the yellow locus. The data obtained were in good agreement with the generally accepted SDSA (synthesis-dependent strand annealing) model. Specific features of P element excision in the presence of two tandemly repeated copies are presented. The pattern of P element excision depended on the sequences surrounding the insertion site and on the number of its additional copies present in the genome.