Processing of a psoralen DNA interstrand cross-link by XPF-ERCC1 complex in vitro
Processing of a psoralen DNA interstrand cross-link by XPF-ERCC1 complex in vitro
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DOI：
10.1074/jbc.m708072200
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发表时间：
2008-01-18
影响因子：
4.8
通讯作者：
Bessho, Tadayoshi
中科院分区：
文献类型：
--
作者：
Fisher, Laura A.;Bessho, Mika;Bessho, Tadayoshi
由DNA链间交联（ICL）引起的分叉停滞的处理被认为是启动哺乳动物ICL修复的重要步骤。为了研究XPF-ERCC1复合体在这一过程中的作用，我们设计了一个模型底物DNA，在三向连接处（y形DNA）有一个单一的补骨脂素ICL，模拟了一个停滞的叉结构。我们发现XPF-ERCC1复合物以损伤依赖的方式在y形DNA上的补骨脂素损伤处形成切口5'。此外，XPF-ERCC1复合物在ICL的3'侧产生ICL特异性切口。在交联的y形DNA上，ICL特异性的3‘切口和5’切口导致两条交联链的分离（ICL的解钩），并在交联位点附近诱导双链断裂。这些结果暗示XPF-ERCC1复合体通过解开ICL来启动ICL修复，同时在停滞的叉处诱导双链断裂。
The processing of stalled forks caused by DNA interstrand cross-links (ICLs) has been proposed to be an important step in initiating mammalian ICL repair. To investigate a role of the XPF-ERCC1 complex in this process, we designed a model substrate DNA with a single psoralen ICL at a three-way junction (Y-shaped DNA), which mimics a stalled fork structure. We found that the XPF-ERCC1 complex makes an incision 5' to a psoralen lesion on Y-shaped DNA in a damage-dependent manner. Furthermore, the XPF-ERCC1 complex generates an ICL-specific incision on the 3'-side of an ICL. The ICL-specific 3'-incision, along with the 5'-incision, on the cross-linked Y-shaped DNA resulted in the separation of the two cross-linked strands (the unhooking of the ICL) and the induction of a double strand break near the cross-linked site. These results implicate the XPF-ERCC1 complex in initiating ICL repair by unhooking the ICL, which simultaneously induces a double strand break at a stalled fork.