Chromosome-specific telomeric associations in Chinese hamster embryonic cells

Telomeric associations (TAs) represent an important cytogenetic marker of h uman tumor cells. It has been thought that the primary cause of TAs is telo mere shortening. However, we report here a surprising aspect of telomere ma intenance in primary Chinese hamster embryonic (CHE) cells: relatively high frequencies of TAs in spite of normal telomere length. These TAs are prese nt in both interphase and metaphase cells, suggesting that metaphase TAs ma y be relies of interphase chromosome organization. In addition, some TAs ob served here are chromosome-specific and recurrent in at least three consecu tive cell cycles in two different CHE cell strains. in spite of relatively high frequencies of TAs, none of the CHE strains show chromosome instabilit y resulting from breakage-fusion-bridge cycles, as would be expected from t umor cell studies. It appears that TAs in CHE cells may be reversible event s. These results are discussed in light of current understanding of telomer e biology. Genes Chromosomes Cancer 28:98-105, 2000. (C) 2000 Wiley-Liss, I nc.