Alterations in telomere lengths affect heterochromatin states of telomeres.

Original paper:

Telomere length regulates the epigenetic status of mammalian telomeres and sub- telomeres

Roberta Benetti, Marta Garcı´a-Cao & Marı´a A Blasco

ABSTART:

This article discusses the various changes that are caused in the telomeric and subtelomeric regions by shortening of the telomeric sequences. Telomeres are designed to be highly condensed sequences governed by heterochromatin domains present at the ends of chromosomes. Experiments conducted with early-passage mouse embryonic fibroblasts (MEFs) derived from wild-type, second generation (G2) and fifth generation (G5) telomerase-null mice, suggested a decrease in the telomeric H3K9 and H4K20 trimethylation and CBX3 binding accompanied by increased acetylation. Although, binding of telomere repeat factors was shown to be unaffected, such histone modifications change the heterochromatin structure to a more euchromatinised structure. The article also described changes in subtelomeric DNA methylations due to telomere shortening which further resulted in increased telomeric recombinations. Such heterochromatic domains were shown to regulate telomeric lengths and hence as indispensible modulators in the overall functioning of the eukaryotic genome.

Omkar Patkar

41812822