An in vivo analysis of MMC-induced DNA damage and its repair
An in vivo analysis of MMC-induced DNA damage and its repair
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DOI：
10.1093/carcin/bgi254
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发表时间：
2006-03-01
期刊：
影响因子：
4.7
通讯作者：
Lee, SH
中科院分区：
文献类型：
--
作者：
Lee, YJ;Park, SJ;Lee, SH
丝裂霉素C（MMC）可诱导多种类型的DNA损伤，从而对细胞产生显著的细胞毒性。因此，MMC诱导的损伤的修复涉及多个修复途径，如核苷酸切除修复、同源重组修复和跨损伤旁路修复途径。然而，MMC诱导的哺乳动物DNA损伤的修复尚未完全阐明。在这项研究中，我们研究了着色性干皮病（XP）蛋白在MMC诱导的DNA损伤修复中的潜在作用，使用检测MMC或8 '-甲氧基-补骨脂素（8-MOP）+ UVA（紫外线A）处理后产生的ssDNA斑块的测定法。人野生型细胞在MMC或8-MOP + UVA处理后形成独特的ssDNA灶，但不与那些诱导烷基化损伤，氧化损伤或链断裂损伤，表明灶代表交联修复过程中形成的ssDNA补丁。与野生型细胞相比，XPE或XPG缺陷突变体在MMC处理后没有形成ssDNA灶，而XPF突变体细胞在形成灶方面表现出显着延迟的反应。XPG在MMC诱导的DNA损伤修复中的积极作用进一步得到以下观察结果的支持：用MMC处理的细胞诱导XPG与染色质的紧密结合，并且XPG的靶向抑制消除MMC诱导的ssDNA灶形成，使细胞对MMC超敏感。总之，我们的研究结果表明，XPG沿着XPE和XPF在MMC诱导的DNA损伤修复中发挥独特的作用。
Mitomycin C (MMC) induces various types of DNA damages that cause significant cytotoxicity to cells. Accordingly, repair of MMC-induced damages involves multiple repair pathways such as nucleotide excision repair, homologous recombination repair and translesion bypass repair pathways. Nonetheless, repair of the MMC-induced DNA damages in mammals have not been fully delineated. In this study, we investigated potential roles for Xeroderma pigmentosum (XP) proteins in the repair of MMC-induced DNA damages using an assay that detects the ssDNA patches generated following treatment with MMC or 8 '-methoxy-psoralen (8-MOP) + UVA (ultraviolet light A). Human wild-type cells formed distinctive ssDNA foci following treatment with MMC or 8-MOP + UVA, but not with those inducing alkylation damage, oxidative damage or strand-break damage, suggesting that the foci represent ssDNA patches formed during the crosslink repair. In contrast to wild-type cells, mutant defective in XPE orXPG did not form the ssDNA foci following MMC treatment, while XPF mutant cells showed a significantly delayed response in forming the foci. A positive role for XPG in the repair of MMC-induced DNA damages was further supported by observations that cells treated with MMC induced a tight association of XPG with chromatin, and a targeted inhibition of XPG abolished MMC-induced ssDNA foci formation, rendering cells hypersensitive to MMC. Together, our results suggest that XPG along with XPE and XPF play unique role(s) in the repair of MMC-induced DNA damages.