Аннотация:Telomere repeats consist of guanine-rich repetitive sequences of nucleotides, which, together with specific proteins, form the telo- meres and play an important role in the maintenance of eukary- otic genome integrity by protecting the ends of chromosomes, serving as substrate for chromosome end elongation by telomer- ase and thus preventing their replicative shortening. Telomeres also marking chromosome ends as allowed double strand breaks. Long terminal tracks of telomere repeats are associated with het- erochromatin, and they regulate the epigenetic modifications, transcriptional activity and replication time of neighboring gen- ome regions. Although the functions of terminal telomere repeats are almost elucidated, there are also internal telomere repeats, the role of which remains unclear. In part, internal telomere repeats may be a reminiscence of some past Robertsonian-like fusions without telomere loss, but there are also a lot of relatively short internal telomere tracks, which are abundant and may play a role in genome structuring. We supposed that some internal telomere repeats may be asso- ciated with regions with high frequency of specific breakage, and focused on the study of regions, flanked by inverted telomere repeats containing at least a single-stranded break on both sides, in the fish Danio rerio. We found that the average length and dis- tribution of such regions is different between organs, and changes with age. Besides telomere repeats at ends, they also contain sequences, which are repeated in genome and partially do not correspond to known classes of repetitive elements. For some telomere-flanked regions the transcriptional activity was proved, and in the majority of them are predicted open reading frames, either corresponding to hypothetical proteins and peptides or homologous to known proteins. We also found, that the labeled probe to one of the telomere-flanked regions reveals particular chromatin structures in fibroblast nucleus, in the organization of which a major role plays the RNA. Thus the telomere-flanked regions may play a role in chromatin organization and genomic imprinting.