Telomere Repeat-Binding Factor 2 Is Responsible for the Telomere Attachment to the Nuclear Membrane.

Abstract

Telomeres are nucleoprotein structures that specify ends of eukaryotic chromosomes. They enable complete DNA replication, protect chromosomes from end-to-end fusions, and help organize chromatin structure. These functions are mediated by special telomeric proteins. TRF2 (telomeric repeat-binding factor 2) is an essential component of shelterin, a telomere-binding protein complex. TRF2 induces formation of a special structure of telomeric DNA, counteracts activation of double-strand break response pathway and ataxia telangiectasia mutated kinase pathway at telomeres. Some line of evidence implicates TRF2 in interactions with the nuclear envelope (NE). TRF2 is tightly bound to the nuclear membrane in frog oocytes nucleus, and it was found colocalized with NE or its remnants in mouse cells. Computer analysis of TRF2 amino acid sequence has shown that TRF2 possesses motifs, which resemble rod domain characteristic of intermediate filament proteins. These observations suggest that TRF2 is a good candidate for the attachment of telomeres to the NE in somatic cells.