Uncoupling of RAD51 focus formation and cell survival after replication fork stalling in RAD51D null CHO cells.
Uncoupling of RAD51 focus formation and cell survival after replication fork stalling in RAD51D null CHO cells.
复制标题
RAD51D 无效 CHO 细胞中复制叉停滞后 RAD51 焦点形成和细胞存活的解偶联。
DOI：
10.1002/em.21672
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发表时间：
2012
影响因子：
2.8
通讯作者：
Thompson,LarryH
中科院分区：
文献类型：
--
作者：
Urbin,SalustraS;Elvers,Ingegerd;Hinz,JohnM;Helleday,Thomas;Thompson,LarryH
在脊椎动物细胞中，五种RAD 51旁系同源物（XRCC 2/3和RAD 51 B/C/D）增强同源重组修复（HRR）的效率。DNA复制叉的停滞和断裂是一种常见的事件，特别是在高等真核生物的大基因组中。当细胞暴露于阻止DNA复制的试剂（如羟基脲或阿非迪霉素）时，叉断裂可导致染色体畸变和细胞杀伤。我们评估了HRR蛋白RAD 51 D在抵抗复制相关DSB杀伤中的作用。如预期的那样，通过诱导RAD 51病灶评估，在对羟基脲的反应中，isogenicrad 51 dnull CHO突变体未能显示出HRR启动的任何迹象。令人惊讶的是，这些细胞对来自羟基脲或阿非迪霉素的复制抑制的杀伤具有正常抗性，但显示出对喜树碱的预期敏感性，喜树碱也产生复制依赖性DSB。相反，我们证实V79 xrcc 2突变体在某些条件下确实显示出对羟基脲的敏感性增加，这与其减弱的RAD 51焦点反应相关。在对PARP 1抑制剂KU 58684的反应中，rad 51 d细胞与其他HRR突变体一样，表现出极高的敏感性（>1000倍），这也与有缺陷的RAD 51病灶形成有关。因此，rad 51 d细胞在响应于各种试剂的RAD 51焦点形成中广泛缺陷，但这种缺陷并不总是与增加的敏感性相关。我们的研究结果表明，RAD 51旁系同源物并不等同于DNA复制抑制剂的细胞耐药性，并且与复制抑制相关的RAD 51病灶可能不是细胞对此类药物耐药性的可靠指标。Environ.摩尔变异体2012.© 2012 Wiley Periodicals，Inc.
In vertebrate cells, the five RAD51 paralogs (XRCC2/3 and RAD51B/C/D) enhance the efficiency of homologous recombination repair (HRR). Stalling and breakage of DNA replication forks is a common event, especially in the large genomes of higher eukaryotes. When cells are exposed to agents that arrest DNA replication, such as hydroxyurea or aphidicolin, fork breakage can lead to chromosomal aberrations and cell killing. We assessed the contribution of the HRR protein RAD51D in resistance to killing by replication‐associated DSBs. In response to hydroxyurea, the isogenicrad51dnull CHO mutant fails to show any indication of HRR initiation, as assessed by induction RAD51 foci, as expected. Surprisingly, these cells have normal resistance to killing by replication inhibition from either hydroxyurea or aphidicolin, but show the expected sensitivity to camptothecin, which also generates replication‐dependent DSBs. In contrast, we confirm that the V79xrcc2mutant does show increased sensitivity to hydroxyurea under some conditions, which was correlated to its attenuated RAD51 focus response. In response to the PARP1 inhibitor KU58684,rad51dcells, like other HRR mutants, show exquisite sensitivity (>1000‐fold), which is also associated with defective RAD51 focus formation. Thus,rad51dcells are broadly deficient in RAD51 focus formation in response to various agents, but this defect is not invariably associated with increased sensitivity. Our results indicate that RAD51 paralogs do not contribute equally to cellular resistance of inhibitors of DNAreplication, and that the RAD51 foci associated with replication inhibition may not be a reliable indicator of cellular resistance to such agents. Environ. Mol. Mutagen. 2012. © 2012 Wiley Periodicals, Inc.