^(60)Co照射后SMMC7721细胞线粒体DNA部分非编码区断裂敏感位点初探

Sensitive breakpoints within non-coding region of mitochondrial DNA in human liver cancer cell line SMMC-7721 irradiated by^(60)Co γ-ray

目的:观察SMMC7721细胞在接受不同剂量60Coγ射线照射后线粒体DNA非编码区是否存在特定的断裂敏感点。方法:根据人线粒体DNA非编码区的基因序列设计相应的引物序列,再通过接头介导PCR(LMPCR)及基因扫描来检测其断裂程度和位点。结果:PCR产物电泳结果显示,接受不同剂量γ射线照射后,各剂量都有相同大小的片段。通过基因扫描的方法,发现不同照射剂量下的断裂位点位置是相同的。结果说明这些断裂敏感位点不是随机分布的。并且,位点的损伤频率也是随着剂量的增加而呈现递增趋势,随着剂量的增加还出现了新的断裂位点。结论:SMMC7721细胞线粒体DNA非编码区确实存在对γ射线敏感的位点。

Objective:To observe whether there are sensitive breakpoints within the mitochondrial DNA non-coding region in a human liver cancer cell line, SMMC-7721, after irradiation with different doses of 60Co γ-ray. Methods: Primers for multiple PCR detection were designed according to the sequence of the human mitochondrial DNA,and the degree and location of mitochondrial DNA breaks were measured by LM-PCR and genescan. Results: Electrophoresis results of PCR products showed fragments of the same length after irradiation with different doses of 60Co γ-ray, indicating that there were common breakpoints under different doses of radiation and the sensitive breakpoints were not distributed at random. Moreover,the degree of damage showed an increasing tendency with the increase of irradiation doses,and new breakpoints appeared with the increase of irradiation doses. Conclusion: γ-ray sensitive break-points do exist in the mitochondrial DNA non-coding region in human liver cancer cell line SMMC-7721.