Defining the function of XPC protein in psoralen and cisplatin-mediated DNA repair and mutagenesis
Defining the function of XPC protein in psoralen and cisplatin-mediated DNA repair and mutagenesis
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DOI：
10.1093/carcin/bgg051
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发表时间：
2003-06-01
期刊：
影响因子：
4.7
通讯作者：
Wang, G
中科院分区：
文献类型：
--
作者：
Chen, ZW;Xu, XXS;Wang, G
DNA损伤识别在DNA修复和突变中起着重要的作用。未能识别DNA损伤可能导致DNA复制而没有损伤修复以及突变积累。突变可导致许多疾病。XPC是一种DNA损伤识别蛋白，在DNA修复过程的早期阶段与受损的DNA模板结合。我们已经研究了XPC蛋白在DNA交联剂peptide和顺铂介导的DNA修复和诱变中的作用。将质粒DNA转染XPC基因缺陷的着色性干皮病C组（XPC）细胞后，观察到非常明显的突变频率和突变谱：质粒DNA损伤的XPC细胞突变频率降低，而质粒DNA损伤的XPC细胞突变频率升高;相比之下，XPC细胞中由pepsilen产生的大多数突变是T到G颠换，而XPC细胞中由顺铂产生的大多数突变是大缺失。我们还通过宿主细胞再活化（HCR）试验和体外DNA修复试验测定了XPC细胞的DNA修复能力。HCR结果显示，在XPC细胞中，荧光素酶报告基因对peptide和顺铂损伤的质粒DNA的宿主细胞再活化大大减少。体外DNA修复结果显示，从XPC细胞制备的核提取物中的peptide和顺铂损伤的质粒DNA的修复能力有缺陷。然而，当在反应之前将功能性XPC蛋白补充到XPC核提取物中时，这种缺陷的DNA修复活性部分恢复。这些结果表明，XPC蛋白DNA损伤识别功能在DNA修复启动和突变避免中起着至关重要的作用，XPC缺陷可能导致突变增加和疾病进展的高风险。
DNA damage recognition plays an important role in DNA repair and mutagenesis. Failure to recognize DNA damage may lead to DNA replication without damage repair as well as mutation accumulation. Mutations can lead to many disease conditions. XPC is a DNA damage recognition protein that binds to damaged DNA templates at a very early stage during the DNA repair process. We have studied the role of the XPC protein in DNA cross-link reagents, psoralen and cisplatin, mediated DNA repair and mutagenesis. When psoralen and cisplatin-damaged plasmid DNA was transfected into xeroderma pigmentosum group C (XPC) cells, which were defective in the XPC gene, very distinct mutation frequency and spectrum was observed: a decreased mutation frequency for psoralen-damaged plasmid and an increased mutation frequency for cisplatin-damaged plasmid; in contrast, most mutations generated by psoralen in XPC cells were T-to-G transversions and most mutations generated by cisplatin in XPC cells were large deletions. We also determined the DNA repair ability of XPC cells by both host cell reactivation (HCR) assay and in vitro DNA repair assay. The HCR results showed greatly reduced host cell reactivation of a luciferase reporter for both psoralen and cisplatin-damaged plasmid DNA in XPC cells. The in vitro DNA repair results revealed a defective repair capacity for both psoralen and cisplatin-damaged plasmid DNA in nuclear extract prepared from XPC cells. However, this defective DNA repair activity was partially restored when a functional XPC protein was supplemented into the XPC nuclear extract prior to the reaction. These results suggest that the XPC protein DNA damage recognition function plays a crucial role in DNA repair initiation and mutation avoidance and XPC defects may lead to increased mutations and high risk for disease progression.