Mutational signatures of non-homologous and polymerase theta-mediated end-joining in embryonic stem cells.
Mutational signatures of non-homologous and polymerase theta-mediated end-joining in embryonic stem cells.
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DOI：
10.15252/embj.201796948
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发表时间：
2017-12-15
期刊：
影响因子：
--
通讯作者：
Tijsterman M
中科院分区：
文献类型：
--
作者：
Schimmel J;Kool H;van Schendel R;Tijsterman M
细胞使用潜在的突变DNA修复机制来避免染色体断裂对细胞生存的有害影响。虽然经典的非同源末端连接(CNHEJ)在很大程度上是无错误的，但已描述了本质上具有突变性的替代末端连接途径。然而，哪些末端连接机制在生殖细胞和胚胎细胞中起作用，从而导致在先天性疾病中发现的可遗传突变，在很大程度上仍然难以捉摸。在这里，我们确定了修复CRISPR/Cas9诱导的不同配置的染色体断裂的遗传要求，并建立了突变后果。我们发现cNHEJ和聚合酶theta介导的末端连接(TMEJ)在小鼠胚胎干细胞中既平行又多余，几乎解释了所有的末端连接活动。令人惊讶的是，聚合酶theta(PolLQ基因编码的Poltheta)对钝性双链断裂(DSB)的突变修复最为普遍，而cNHEJ决定了末端突出的DSB的突变修复，其中cNHEJ聚合酶Lambda和Mu起次要作用。我们得出结论，cNHEJ依赖的末端突出的DSB的修复可以解释哺乳动物基因组中串联复制的从头形成。
Cells employ potentially mutagenic DNA repair mechanisms to avoid the detrimental effects of chromosome breaks on cell survival. While classical non‐homologous end‐joining (cNHEJ) is largely error‐free, alternative end‐joining pathways have been described that are intrinsically mutagenic. Which end‐joining mechanisms operate in germ and embryonic cells and thus contribute to heritable mutations found in congenital diseases is, however, still largely elusive. Here, we determined the genetic requirements for the repair of CRISPR/Cas9‐induced chromosomal breaks of different configurations, and establish the mutational consequences. We find that cNHEJ and polymerase theta‐mediated end‐joining (TMEJ) act both parallel and redundant in mouse embryonic stem cells and account for virtually all end‐joining activity. Surprisingly, mutagenic repair by polymerase theta (Pol θ, encoded by the Polq gene) is most prevalent for blunt double‐strand breaks (DSBs), while cNHEJ dictates mutagenic repair of DSBs with protruding ends, in which the cNHEJ polymerases lambda and mu play minor roles. We conclude that cNHEJ‐dependent repair of DSBs with protruding ends can explain de novo formation of tandem duplications in mammalian genomes.
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影响因子：
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作者：
Ceccaldi R;Rondinelli B;D'Andrea AD
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通讯作者：
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