[Barrier elements of chromatin domains and nuclear envelope].

The results of investigating the functions of different barrier elements, including insulators and MARs/SARs and the models of their effect, are described. The functions of neDNA (DNA from the nuclear envelopes) as a barrier element that protects the transgene from position-effect variegation and its interaction with insulators are discussed. The possible mechanisms of the functioning of structural and functional units of eukaryotic chromosomes of different species are suggested.

[Nuclear envelope attachment sites of interphase chromosomes: barrier elements but not insulators].

A neDNA fragment that protects a transgene from position effect variegation when flanking it was tested for insulator properties. The fragment did not act as an insulator. A similarity of neDNA and various barrier elements was examined, and Drosophila melanogaster and Mus musculus chromosome DNA regions homologous to neDNA were analyzed.

[The role of chromosomal regions anchored to the nuclear envelope in the functional organization of chromosomes].

The functional characteristics of the DNA fragments responsible for chromosome attachment to the nuclear envelope during the interphase (neDNAs) have been studied. The neDNAs flanking the transgene have been found to promote a steadily high rate of its expression, irrespective of the site of its insertion into the host chromosomes. At the same time, neDNAs themselves have no transcription regulatory functions.

[Unusual nucleotide sequence of a DNA fragment isolated from nuclear envelopes of mouse hepatocytes].

Fragments of chromosomal DNA isolated from nuclear envelopes of mouse hepatocytes were previously cloned and partially characterized in our laboratory. One of the cloned fragments (EnvM4) had unusual characteristics: abundant representability in the clone library (about 50%) and homology with DNA of archebacteria. An analysis of nucleotide sequence of this fragment conducted in more detail allowed the detection of an evolutionary conserved region present in the genomes of various organisms (from bacteria to human).