Repair of an interstrand DNA cross-link initiated by ERCC1-XPF repair/recombination nuclease
Repair of an interstrand DNA cross-link initiated by ERCC1-XPF repair/recombination nuclease
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DOI：
10.1074/jbc.c000337200
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发表时间：
2000-08-25
影响因子：
4.8
通讯作者：
Wood, RD
中科院分区：
文献类型：
--
作者：
Kuraoka, I;Kobertz, WR;Wood, RD
链间DNA交联损伤是对基因组完整性的严重挑战。核苷酸切除修复在修复由昆虫和其他因子引起的DNA交联中起一定作用。然而，在哺乳动物细胞中，有证据表明ERCC 1-XPF核酸酶在链间DNA交联修复过程中具有专门的额外功能，超出其在核苷酸切除修复中的作用。我们在双链体中放置了一个卟啉单加合物或链间交联，距离与未配对DNA的连接点4-6个碱基。ERCC 1-XPF在加合物的任一侧上的双链体内在具有未配对3'尾的链上被内切核酸裂解。纯化仅在5'侧切割的交联，并与ERCC 1-XPF再孵育。然后在3'侧观察到第二次切割。交联附近的相关部分解绕结构可能会频繁出现，例如在停滞的DNA复制叉处。结果表明，单一酶ERCC 1-XPF可以释放交联的一个臂，并提出了一种新的链间交联修复机制。
Interstrand DNA cross-link damage is a severe challenge to genomic integrity. Nucleotide excision repair plays some role in the repair of DNA cross-links caused by psoralens and other agents. However, in mammalian cells there is evidence that the ERCC1-XPF nuclease has a specialized additional function during interstrand DNA cross-link repair, beyond its role in nucleotide excision repair. We placed a psoralen monoadduct or interstrand cross-link in a duplex, 4-6 bases from a junction with unpaired DNA. ERCC1-XPF endonucleolytically cleaved within the duplex on either side of the adduct, on the strand having an unpaired 3' tail. Crosslinks that were cleaved only on the 5' side were purified and reincubated with ERCC1-XPF, A second cleavage was then observed on the 3' side. Relevant partially unwound structures near a cross-link may be expected to arise frequently, for example at stalled DNA replication forks. The results show that the single enzyme ERCC1-XPF can release one arm of a cross-link and suggest a novel mechanism for interstrand cross-link repair.