RPA activates the XPF-ERCC1 endonuclease to initiate processing of DNA interstrand crosslinks.
RPA activates the XPF-ERCC1 endonuclease to initiate processing of DNA interstrand crosslinks.
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DOI：
10.15252/embj.201796664
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发表时间：
2017-07-14
期刊：
影响因子：
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通讯作者：
McHugh PJ
中科院分区：
文献类型：
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作者：
Abdullah UB;McGouran JF;Brolih S;Ptchelkine D;El-Sagheer AH;Brown T;McHugh PJ
在复制偶联DNA链间交联（ICL）修复过程中，XPF-ERCC 1核酸内切酶是释放或“脱钩”ICL的切口所必需的，但ICL脱钩的机制在很大程度上仍然未知。当复制叉的新生前导链撞击ICL时，切口被触发。在这里，我们报告说，虽然纯化的XPF-ERCC 1切割简单的含ICL的模型复制叉结构，但新生前导链的存在，模拟复制停滞的影响，抑制了这种活性。引人注目的是，添加单链DNA（ssDNA）结合复制蛋白A（RPA）选择性地恢复了XPF-ERCC 1内切核酸酶在该结构上的活性。5′-3′核酸外切酶SNM 1A可以从XPF-ERCC 1-RPA-诱导的切口加载并消化通过交联以定量完成脱钩反应。我们假设XPF-ERCC 1、RPA和SNM 1A的这些协作活动可以解释ICL如何在体内实现脱钩。
During replication‐coupled DNA interstrand crosslink (ICL) repair, the XPF‐ERCC1 endonuclease is required for the incisions that release, or “unhook”, ICLs, but the mechanism of ICL unhooking remains largely unknown. Incisions are triggered when the nascent leading strand of a replication fork strikes the ICL. Here, we report that while purified XPF‐ERCC1 incises simple ICL‐containing model replication fork structures, the presence of a nascent leading strand, modelling the effects of replication arrest, inhibits this activity. Strikingly, the addition of the single‐stranded DNA (ssDNA)‐binding replication protein A (RPA) selectively restores XPF‐ERCC1 endonuclease activity on this structure. The 5′–3′ exonuclease SNM1A can load from the XPF‐ERCC1‐RPA‐induced incisions and digest past the crosslink to quantitatively complete the unhooking reaction. We postulate that these collaborative activities of XPF‐ERCC1, RPA and SNM1A might explain how ICL unhooking is achieved in vivo.