Telomeric Repeat Binding Factor 2 (TERF2)

TERF2, which is a component of the telomere nucleoprotein complex. This protein is present at telomeres in metaphase of the cell cycle, is a second negative regulator of telomere length and plays a key role in the protective activity of telomeres. While having similar telomere binding activity and domain organization, TERF2 differs from TERF1 in that its N terminus is basic rather than acidic. TRF2 may protect chromosome ends by maintaining the correct structure at telomere termini. In addition, expression of mutant forms of TRF2 induced a growth arrest with characteristics of senescence. These results raise the possibility that chromosome end fusions and senescence in primary human cells may be caused by loss by TRF2 from shortened telomeres.