ERCC2/XPD基因缺失对苯并[a]芘所致DNA损伤修复的影响

Effect of deficient ERCC2/XPD gene on the repair of DNA damage induced by benzo[a]pyrene

目的:探讨核苷酸切除修复交叉互补基因2(excision repair cross complementation group2/Xeroderma pigmentosum D,ERCC2/XPD)在苯并[a]芘所诱导的细胞DNA损伤与修复过程中的作用。方法:应用中国仓鼠卵巢细胞系CHO野生型AA8和ERCC2表达缺失型UV5作为细胞对照模型,MTT法比较两种细胞经苯并[a]芘处理后细胞抑制率的差别;彗星试验和Rad51免疫荧光试验检测不同浓度苯并[a]芘处理及修复24h后细胞DNA损伤修复的情况。结果:与野生型AA8细胞相比,UV5细胞对苯并[a]芘所致损伤更加敏感,细胞存活率降低(P<0.05)。彗星试验和Rad51免疫荧光试验结果显示,UV5细胞由于缺失ERCC2/XPD基因,修复苯并[a]芘所致DNA损伤能力降低(P<0.05)。结论:ERCC2/XPD蛋白在核苷酸切除修复中发挥解旋作用,对苯并[a]芘所致DNA损伤修复至关重要。

OBJECTIVE：To investigate ERCC2/XPD （excision repair cross complementation group 2/Xeroderma pigmentosum D） function in the repair of DNA damage induced by benzo[a]pyrene. METHODS：China hamster ovary （CHO） cell line including wild type AA8 and ERCC2/XPD defective mutant UV5,was set up as a cell contrast model. DNA damage levels at different time points after benzo[a]pyrene treatment were evaluated by MTT cell inhibition assay,modified comet assay and Rad51 immunofluorescence test. RESULTS：UV5 was more sensitive to benzo[a]pyrene when compared with AA8. The DNA damage caused by benzo[a]pyrene was repaired by AA8 but not by UV5. CONCLUSION：ERCC2/XPD,as an important helicase in nucleotide excision repair,could play a critical role in repairing DNA damage induced by benzo[a]pyrene.