Cell cycle control of telomere protection and NHEJ revealed by a ts mutation in the DNA-binding domain of TRF2
Abstract
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°C, TRF2ts was functional and rescued the lethality of TRF2 deletion from conditional TRF2F/− mouse embryonic fibroblasts (MEFs). When shifted to the nonpermissive temperature (37°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°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.
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Footnotes
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↵1 Present address: Medical Top Track (MTT) Program, Medical Research Institute, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8510, Japan.
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↵2 Correspondending author.
↵2 E-MAIL delange{at}mail.rockefeller.edu; FAX (212) 327-7147.
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Supplemental material is available at http://www.genesdev.org.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.1634008.
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- Received November 14, 2007.
- Accepted March 10, 2008.
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Freely available online through the Genes & Development Open Access option.
- Copyright © 2008, Cold Spring Harbor Laboratory Press