The MRE11 GAR motif regulates DNA double-strand break processing and ATR activation
The MRE11 GAR motif regulates DNA double-strand break processing and ATR activation
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DOI：
10.1038/cr.2011.128
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发表时间：
2011-08
期刊：
影响因子：
44.1
通讯作者：
Zhenbao Yu;G. Vogel;Yan Coulombe;Dan Dubeau;Elizabeth I. Spehalski;J. Hébert;D. Ferguson;J. Masson;S. Richard
中科院分区：
文献类型：
--
作者：
Zhenbao Yu;G. Vogel;Yan Coulombe;Dan Dubeau;Elizabeth I. Spehalski;J. Hébert;D. Ferguson;J. Masson;S. Richard
MRE 11/RAD 50/NBS 1复合物是快速募集到DNA双链断裂（DSB）的主要传感器。已知MRE 11在其富含甘氨酸-精氨酸（GAR）基序内被PRMT 1精氨酸甲基化。在这项研究中，我们报告了一个小鼠敲入等位基因的MRE 11取代的赖氨酸的GAR基序中的丝氨酸，并产生MRE 11 RK蛋白缺乏甲基化丝氨酸。Mre 11 RK/RK小鼠对γ射线照射（IR）高度敏感，其细胞表现出细胞周期检查点缺陷和染色体不稳定。此外，Mre 11 RK/RK MEFs表现出ATR/CHK 1信号传导缺陷和RPA和RAD 51向受损部位的募集受损。MRK RN复合物形成并定位于DNA损伤位点，并在IR时正常激活ATM通路。MRK RN复合物在体外表现出核酸外切酶和DNA结合缺陷，导致在体内观察到IR时DNA末端切除受损和ATR激活。我们的研究结果为MRE 11 GAR基序在DSB修复中的关键作用提供了遗传学证据，并证明了MRE 11 GAR基序的翻译后修饰与DSB加工以及ATR/CHK 1检查点信号传导之间的机制联系。
The MRE11/RAD50/NBS1 complex is the primary sensor rapidly recruited to DNA double-strand breaks (DSBs). MRE11 is known to be arginine methylated by PRMT1 within its glycine-arginine-rich (GAR) motif. In this study, we report a mouse knock-in allele of Mre11 that substitutes the arginines with lysines in the GAR motif and generates the MRE11 RK protein devoid of methylated arginines. The Mre11 RK/RK mice were hypersensitive to γ-irradiation (IR) and the cells from these mice displayed cell cycle checkpoint defects and chromosome instability. Moreover, the Mre11 RK/RK MEFs exhibited ATR/CHK1 signaling defects and impairment in the recruitment of RPA and RAD51 to the damaged sites. The M RK RN complex formed and localized to the sites of DNA damage and normally activated the ATM pathway in response to IR. The M RK RN complex exhibited exonuclease and DNA-binding defects in vitro responsible for the impaired DNA end resection and ATR activation observed in vivo in response to IR. Our findings provide genetic evidence for the critical role of the MRE11 GAR motif in DSB repair, and demonstrate a mechanistic link between post-translational modifications at the MRE11 GAR motif and DSB processing, as well as the ATR/CHK1 checkpoint signaling.