骨肉瘤细胞中H3K79me2，3参与有丝分裂期调控的研究

Investigation of the role of H3K79me2，3 on mitotic progression in osteosarcoma cells

摘要:

目的：为了研究组蛋白3第79位赖氨酸二甲基化和三甲基化（H3K79me2，3）水平在骨肉瘤细胞有丝分裂期的变化及对有丝分裂期进程的影响。方法：利用细胞周期同步化方法，观察骨肉瘤细胞U2OS在有丝分裂期前中期到出有丝分裂期各阶段H3K79me2，3水平的变化；并用特异性抑制剂EPZ5676抑制H3K79甲基化水平，用Western blot及活细胞荧光激光共聚焦检测其对有丝分裂期进程的影响。结果：在骨肉瘤细胞U2OS中，H3K79me2，3水平在有丝分裂期前中期下降，并随着细胞出有丝分裂期，H3K79me2，3水平逐渐增加，使用抑制剂进一步降低其在有丝分裂期的水平并抑制其随后的增加，对有丝分裂期中期到后期的转化过程影响不明显，但会引起姐妹染色单体分离错误出现的比例增高（χ2=4.99，P=0.026）。结论：H3K79me2，3水平在骨肉瘤有丝分裂期前中期降低，并随着细胞出有丝分裂期逐渐升高，这种变化可能与确保姐妹染色单体正确分离的相关调控有关。

Abstract:

Objective：To determine the H3K79me2，3 level in osteosarcoma cells during mitosis and to investigate its potential influence on mitotic progression. Methods：Western blot was used to detect the H3K79me2，3 level in osteosarcoma cells after mitotic synchro－nization. Time-lapse imaging was performed with a laser confocal fluorescence microscope to monitor the mitotic progression of U2OS cells with or without inhibitor EPZ5676. Results：The H3K79me2，3 level in osteosarcoma cells declined in the prometaphase and then increased gradually with mitosis exit. Depletion of H3K79me2，3 and the following increase caused an increase in the percentage of chromosome missegregation，with no significant effect on the kinetics of mitosis exit（χ2=4.99，P=0.026）. Conclusion：The H3K79me2，3 level shows variations during mitosis in osteosarcoma cells and is related to the regulation of chromosome segregation.