Involvement of XRCC1 and DNA ligase III gene products in DNA base excision repair
Involvement of XRCC1 and DNA ligase III gene products in DNA base excision repair
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DOI：
10.1074/jbc.272.38.23970
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发表时间：
1997-09-19
影响因子：
4.8
通讯作者：
Frosina, G
中科院分区：
文献类型：
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作者：
Cappelli, E;Taylor, R;Frosina, G
DNA连接酶III和必需蛋白XRCC 1在xrcc 1突变的CHO细胞系EM-C 11中的水平大大降低。从这些细胞制备的无细胞提取物用于检测XRCC 1基因产物在体外DNA碱基切除修复中的作用。与野生型CHO-9提取物相比，EM-C11细胞提取物在碱基切除修复补丁的连接中存在部分缺陷，在碱基切除修复途径的两个分支中，仅单核苷酸插入途径受到影响;在增殖细胞核抗原依赖性途径中未观察到连接缺陷。EM-C11提取物中连接缺陷的完全互补是通过加入重组人DNA连接酶III的修复反应实现的，但不是通过XRCC 1。这与XRCC 1作为DNA连接酶III的重要稳定因子的概念一致。这些数据首次证明，xrcc 1突变细胞在碱基切除修复补丁的连接中部分缺陷，并且该缺陷对聚合酶β依赖性单核苷酸插入途径具有特异性。
DNA ligase III and the essential protein XRCC1 are present at greatly reduced levels in the xrcc1 mutant CHO cell line EM-C11, Cell-free extracts prepared from these cells were used to examine the role of the XRCC1 gene product in DNA base excision repair is vitro. EM-C11 cell extract was partially defective in ligation of base excision repair patches, in comparison to wild type CHO-9 extracts, Of the two branches of the base excision repair pathway, only the single nucleotide insertion pathway was affected; no ligation defect was observed in the proliferating cell nuclear antigen-dependent pathway. Full complementation of the ligation defect in EM-C11 extracts was achieved by addition to the repair reaction of recombinant; human DNA ligase III but not by XRCC1. This is consistent with the notion that XRCC1 acts as an important stabilizing factor of DNA ligase III. These data demonstrate for the first time that xrcc1 mutant cells are partially defective in ligation of base excision repair patches and that the defect is specific to the polymerase beta-dependent single nucleotide insertion pathway.