Telomere DNA sequences and the concept of ontogenetic reserve cells.

ABSTRACT

Dynamics of telomere sequences are considered in normal and immortalized cells. Immortalized cells are suggested to be derived mainly from a special subpopulation of ontogenetic reserve cells. Their epigenetic program consists of autoregeneration during external stimulus for genome reorganization and corresponding appearance of genetic variants of cells. It is suggested that cells surviving the crisis stage contain a special signal sequence integrated into telomere DNA. Its elimination during shortening of DNA telomere sequences in dividing ontogenetic reserve cells is a signal for the cooperative transition of chromatin into a new steady state that corresponds to the epigenotype of immortalized cells. Localization of telomere DNA sequences in intrachromosomal "hot spots" reflects phylogenetic rearrangement of the genome.