Poly (ADP-ribose) polymerase (PARP) is not involved in base excision repair but PARP inhibition traps a single-strand intermediate.
Poly (ADP-ribose) polymerase (PARP) is not involved in base excision repair but PARP inhibition traps a single-strand intermediate.
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DOI：
10.1093/nar/gkq1241
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发表时间：
2011-04
影响因子：
14.9
通讯作者：
Helleday T
中科院分区：
文献类型：
--
作者：
Ström CE;Johansson F;Uhlén M;Szigyarto CA;Erixon K;Helleday T
碱基切除修复（BER）是内源性DNA损伤最重要的修复途径。最初，碱基损伤被识别、切除，并形成DNA单链断裂（SSB）中间体。然后连接SSB，这是一个使用也参与SSB修复的蛋白质的过程，例如XRCC 1，连接酶III和可能的PARP 1。在这里，我们证实了XRCC 1和PARP在直接SSB修复中的作用。有趣的是，我们发现了XRCC 1缺陷和PARP抑制之间的合成致死性。我们还用烷基化剂硫酸二甲酯（DMS）处理细胞，并监测BER过程中形成的SSB中间体。DMS诱导的SSB在野生型细胞中快速修复;而在切割后修复被PARP抑制剂或XRCC 1缺陷阻断的细胞（EM 9细胞）中观察到SSB的快速积累。有趣的是，DMS诱导的SSB不在PARP 1 siRNA耗尽的细胞中积累，表明PARP 1不是BER有效完成所必需的。基于这些结果，我们认为PARP 1在BER中没有直接作用，但PARP抑制剂将PARP捕获在BER期间形成的SSB中间体上。出乎意料的是，在DMS处理后2小时添加PARP抑制剂仍然增加SSB水平，表明即使在这个晚期时间点也在进行修复。
Base excision repair (BER) represents the most important repair pathway of endogenous DNA lesions. Initially, a base damage is recognized, excised and a DNA single-strand break (SSB) intermediate forms. The SSB is then ligated, a process that employs proteins also involved in SSB repair, e.g. XRCC1, Ligase III and possibly PARP1. Here, we confirm the role of XRCC1 and PARP in direct SSB repair. Interestingly, we uncover a synthetic lethality between XRCC1 deficiency and PARP inhibition. We also treated cells with alkylating agent dimethyl sulfate (DMS) and monitored the SSB intermediates formed during BER. DMS-induced SSBs were quickly repaired in wild-type cells; while a rapid accumulation of SSBs was observed in cells where post-incision repair was blocked by a PARP inhibitor or by XRCC1 deficiency (EM9 cells). Interestingly, DMS-induced SSBs did not accumulate in PARP1 siRNA depleted cells, demonstrating that PARP1 is not required for efficient completion of BER. Based on these results we suggest no immediate role for PARP1 in BER, but that PARP inhibitors trap PARP on the SSB intermediate formed during BER. Unexpectedly, addition of PARP inhibitor 2 h after DMS treatment still increased SSB levels indicating ongoing repair even at this late time point.
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影响因子：
64.5
作者：
Loizou, JI;El-Khamisy, SF;Caldecott, KW
通讯作者：
Caldecott, KW
影响因子：
4.8
作者：
Cappelli, E;Taylor, R;Frosina, G
通讯作者：
Frosina, G
影响因子：
5.3
作者：
Fisher, Anna E. O.;Hochegger, Helfrid;Caldecott, Keith W.
通讯作者：
Caldecott, Keith W.
影响因子：
14.9
作者：
El-Khamisy, SF;Masutani, M;Caldecott, KW
通讯作者：
Caldecott, KW
影响因子：
4.8
作者：
Prasad, R;Lavrik, OI;Wilson, SH
通讯作者：
Wilson, SH