Cell cycle control of telomere protection and NHEJ revealed by a ts mutation in the DNA-binding domain of TRF2
Cell cycle control of telomere protection and NHEJ revealed by a ts mutation in the DNA-binding domain of TRF2
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DOI：
10.1101/gad.1634008
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发表时间：
2008-05-01
影响因子：
10.5
通讯作者：
de lange, Titia
中科院分区：
文献类型：
--
作者：
Konishi, Akimitsu;de lange, Titia
TRF2是shelterin的一个组成部分，shelterin是一种端粒特异性蛋白复合物，可防止哺乳动物染色体自然末端的DNA损伤信号和不适当的修复。我们描述了TRF2的Myb/SANT DNA结合结构域中的温度敏感性（ts）突变，该突变允许可控和可逆的端粒去保护。在32 ° C下，TRF2ts是功能性的，并且从条件性TRF2（F/-）小鼠胚胎成纤维细胞（MEF）中挽救了TRF2缺失的致死性。当转移到非允许温度（37摄氏度），TRF2ts细胞表现出广泛的端粒损伤，导致ATM激酶和染色体末端的非同源末端连接（NHEJ）的激活。TRF2ts在37 ℃下的失活是快速和可逆的，允许在细胞周期的G0、G1和S/G2期诱导短时间（3 - 6小时）的端粒功能障碍。结果表明，端粒功能障碍的诱导和保护状态的重建可以发生在整个间期。相反，NHEJ对功能失调的端粒的处理主要发生在G1期，在S/G2期以细胞周期蛋白依赖性激酶（CDK）依赖的方式被抑制。
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 odeprotection. 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.