TRF2 is required for repair of nontelomeric DNA double-strand breaks by homologous recombination.
TRF2 (telomeric repeat binding factor 2) is an essential component of the telomeric cap, where it forms and stabilizes the T-loop junctions. TRF2 forms the T-loops by stimulating strand invasion of the 3' overhang into duplex DNA. TRF2 also has been shown to localize to nontelomeric DNA double-strand breaks, but its functional role in DNA repair has not been examined. Here, we present evidence that TRF2 is involved in homologous recombination (HR) repair of nontelomeric double-strand breaks. Depletion of TRF2 strongly inhibited HR and delayed the formation of Rad51 foci after gamma-irradiation, whereas overexpression of TRF2 stimulated HR. Depletion of TRF2 had no effect on nonhomologous end-joining, and overexpression of TRF2 inhibited nonhomologous end-joining. We propose, based on our results and on the ability of TRF2 to mediate strand invasion, that TRF2 plays an essential role in HR by facilitating the formation of early recombination intermediates.
Department of Biology, University of Rochester, Rochester, NY 14627-0211, USA.
Zhiyong
Z
Mao
Andrei
A
Seluanov
Ying
Y
Jiang
Vera
V
Gorbunova
D002478:Cells, Cultured; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D006801:Humans; D009687:Nuclear Proteins / Q000502:physiology*; D051135:Rad51 Recombinase / Q000032:analysis; D011995:Recombination, Genetic; D035182:TATA Box Binding Protein-Like Proteins / Q000502:physiology*; D035341:Telomeric Repeat Binding Protein 2
D009687:Nuclear Proteins; D035182:TATA Box Binding Protein-Like Proteins; C504753:TERF2 protein, human; D035341:Telomeric Repeat Binding Protein 2; C495153:RAD51 protein, human; D051135:Rad51 Recombinase