Human CtIP mediates cell cycle control of DNA end resection and double strand break repair.
Human CtIP mediates cell cycle control of DNA end resection and double strand break repair.
复制标题
人CTIP介导DNA终端切除和双链断裂修复的细胞周期控制。
DOI：
10.1074/jbc.m808906200
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发表时间：
2009-04-03
期刊：
影响因子：
--
通讯作者：
Jackson SP
中科院分区：
文献类型：
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作者：
Huertas P;Jackson SP
在G0和G1中，DNA双链断裂是通过非同源末端连接修复的，而在S和G2中，它们也是通过同源重组修复的。人CtIP蛋白控制双链断裂(DSB)切除，这一事件仅在S/G2中有效发生，促进同源重组，但不促进非同源末端连接。在这里，我们突变了CtIP中一个高度保守的细胞周期蛋白依赖激酶(CDK)的目标基序，并揭示了将Thr-847突变为Ala会损害切除，而将其突变为Glu以模拟结构性磷酸化不会影响切除。此外，我们还发现，与表达野生型CtIP的细胞不同，表达Thr-to-Glu突变体的细胞即使在CDK被抑制后也会切除DSB。最后，我们确定Thr-847突变为Ala或Glu会影响DSB修复效率，导致对DSB生成剂的超敏反应，并影响辐射诱导的染色体重排的频率和性质。这些结果表明，CDK介导的人类细胞切除的控制机制与最近在酵母中建立的机制相似。
In G0 and G1, DNA double strand breaks are repaired by nonhomologous end joining, whereas in S and G2, they are also repaired by homologous recombination. The human CtIP protein controls double strand break (DSB) resection, an event that occurs effectively only in S/G2 and that promotes homologous recombination but not non-homologous end joining. Here, we mutate a highly conserved cyclin-dependent kinase (CDK) target motif in CtIP and reveal that mutating Thr-847 to Ala impairs resection, whereas mutating it to Glu to mimic constitutive phosphorylation does not. Moreover, we show that unlike cells expressing wild-type CtIP, cells expressing the Thr-to-Glu mutant resect DSBs even after CDK inhibition. Finally, we establish that Thr-847 mutations to either Ala or Glu affect DSB repair efficiency, cause hypersensitivity toward DSB-generating agents, and affect the frequency and nature of radiation-induced chromosomal rearrangements. These results suggest that CDK-mediated control of resection in human cells operates by mechanisms similar to those recently established in yeast.