G1和G2期细胞对X射线引起双链DNA断裂修复的影响.pdfVIP

中国临床医学 2007年12月 第14卷 第6期 Clinical Medical Journal of China，2007．Vo1．14，No．6 895 · 论著 · G。和G2期细胞对X射线引起双链 DNA断裂修复的影响 吴伟忠 George Iliakis! 刘康达 摘要 目的：探讨x射线对G1和G!期细胞双链DNA断裂损伤修复的动力学影响。方法：采用3 多聚甲醛或7O 乙醇固定 受x射线放射细胞的M059J、M059K和Hela，用流式细胞仪分选G1和G!期Hela细胞，以脉 中场电泳分析双链 DNA断裂修 复动力学。结果：乙醇固定不影响x射线放射引起的双链DNA断裂修复动力学，可用于固定Hela细胞G-和G 期的分选，且 期细胞双链 DNA断裂修复速率显著慢于G 期细胞。结论：G 和G!期细胞中的双链DNA断裂可能采用不同的修复方式。 G，期细胞主要采用快速的末端连接修复方式，而G!期细胞主要采用相对较慢的同源性重组修复方式。 关键词 非同源性末端连接； 同源性重组； 双链DNA断裂； 细胞周期； X射线放射 中图分类号 R81 8 文献标识码 A Effects of G1 and G2 Cells on DNA Double Stand Breaks Repair Kinetics Induced by X—ray Irradiation WU Weizhong JLJAKJS George LJUKangda 1． Liver Cancer Institute and Zhongshan Hospital， Fudan Univeristy，Shanghai 200032；2．Institute of Medical Radiation Biology，University Duisburg— EsseH Medical School。Esxell 45 1 22。German Abstract Obtjective：To study DNA Double Stand Breaks(DSB)repair kinetics in X—ray irradiated G1 and G cells．Methods：X— ray irradiated M059J，M059K and Hela cells were fixed with 70 ethanol or 3 paraforrnaldehyde，and G1 and G Hela cells were sorted by flow cytometry．DSB repair kinetics was analyzed by pulsed field gel e1ectrophoresis．Results：No significant effects of DSB repair kinetics were found in ethanol fixed cells compared tO their non—fixed counterpart，and ethanol fixed Hela cells were suitable for sorting G1 and G cells．Furthermore，a slower repair kinetics in G cells were found than in G1 cells． Conclusion：G1 and( phase cells might recruit distinct repair pathways tO deal with X—ray induced DSBs．DSBs in G1 cells might prefer tO be repaired by nonhomologous end joining(NHEJ)while DSBs in G cells might prefer tO be repaired by homjol ogous recombination(HRR)． Key Words Nonhomo1ogous end—joining(N HEJ)； Homologous recombination(HRR)； DNA double strand brea