MRN, CtIP, and BRCA1 mediate repair of topoisomerase II-DNA adducts.
MRN, CtIP, and BRCA1 mediate repair of topoisomerase II-DNA adducts.
复制标题
DOI：
10.1083/jcb.201504005
复制
发表时间：
2016-02-15
期刊：
影响因子：
--
通讯作者：
Gautier J
中科院分区：
文献类型：
--
作者：
Aparicio T;Baer R;Gottesman M;Gautier J
在非洲爪蟾卵提取物的分析表明，MRN复合物，CtIP，BRCA 1，和CtIP和BRCA 1之间的相互作用所需的去除Top2-DNA加合物，forsubsequent切除Top2-加合双链断裂末端，并在基因组DNA复制过程中对依托泊苷的细胞抗性。具有复杂末端的DNA双链断裂（DSB）的修复提出了特殊的挑战，因为在DNA连接之前需要额外的处理。例如，必须去除蛋白质-DNA加合物以允许通过非同源末端连接或同源定向修复进行修复。在这里，我们研究了拓扑异构酶II（Top2）-DNA加合物的处理与化疗药物依托泊苷治疗诱导。通过非洲爪蟾卵提取物的生化分析，我们建立了MRN（Mre 11，Rad 50和Nbs 1）复合物，CtIP和BRCA 1是去除Top2-DNA加合物和随后切除Top2-加合的DSB末端所必需的。此外，CtIP和BRCA 1之间的相互作用，虽然切除核酸内切酶产生的DSB末端，是必要的切除Top2-加合的DSB，以及在基因组DNA复制过程中的细胞对依托泊苷的耐药性。
Analyses in Xenopus egg extracts show that the MRN complex, CtIP, BRCA1, and the interaction between CtIP and BRCA1 are required for the removal of Top2–DNA adducts, forsubsequent resection of Top2-adducted double-strand break ends, and for cellular resistance to etoposide during genomic DNA replication. Repair of DNA double-strand breaks (DSBs) with complex ends poses a special challenge, as additional processing is required before DNA ligation. For example, protein–DNA adducts must be removed to allow repair by either nonhomologous end joining or homology-directed repair. Here, we investigated the processing of topoisomerase II (Top2)–DNA adducts induced by treatment with the chemotherapeutic agent etoposide. Through biochemical analysis in Xenopus laevis egg extracts, we establish that the MRN (Mre11, Rad50, and Nbs1) complex, CtIP, and BRCA1 are required for both the removal of Top2–DNA adducts and the subsequent resection of Top2-adducted DSB ends. Moreover, the interaction between CtIP and BRCA1, although dispensable for resection of endonuclease-generated DSB ends, is required for resection of Top2-adducted DSBs, as well as for cellular resistance to etoposide during genomic DNA replication.