Cell cycle control of telomere protection and NHEJ revealed by a ts mutation in the DNA-binding domain of TRF2.
TRF2 is a component of shelterin, the telomere-specific protein complex that prevents DNA damage signaling and inappropriate repair at the natural ends of mammalian chromosomes. We describe a temperature-sensitive (ts) mutation in the Myb/SANT DNA-binding domain of TRF2 that allows controlled and reversible telomere deprotection. At 32 degrees C, TRF2ts was functional and rescued the lethality of TRF2 deletion from conditional TRF2(F/-) mouse embryonic fibroblasts (MEFs). When shifted to the nonpermissive temperature (37 degrees C), TRF2ts cells showed extensive telomere damage resulting in activation of the ATM kinase and nonhomologous end-joining (NHEJ) of chromosome ends. The inactivation of TRF2ts at 37 degrees C was rapid and reversible, permitting induction of short periods (3-6 h) of telomere dysfunction in the G0, G1, and S/G2 phases of the cell cycle. The results indicate that both the induction of telomere dysfunction and the re-establishment of the protected state can take place throughout interphase. In contrast, the processing of dysfunctional telomeres by NHEJ occurred primarily in G1, being repressed in S/G2 in a cyclin-dependent kinase (CDK)-dependent manner.
Konishi
Akimitsu
A
Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10065, USA.
de Lange
Titia
T
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000235:genetics* / Q000502:physiology; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D016521:Electrophoresis, Gel, Pulsed-Field; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D016193:G1 Phase / Q000235:genetics / Q000502:physiology; D016195:G2 Phase / Q000235:genetics / Q000502:physiology; D015151:Immunoblotting; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic / Q000235:genetics*; D016192:Resting Phase, Cell Cycle / Q000235:genetics / Q000502:physiology; D016196:S Phase / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D016615:Telomere / Q000235:genetics* / Q000378:metabolism; D035341:Telomeric Repeat Binding Protein 2 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
D035341:Telomeric Repeat Binding Protein 2