下调SMU1表达对细胞增殖和DNA双链断裂损伤反应的影响  

Down-regulation of SMU1 Expression Infl uence Cell Proliferation and Cellular Response to DNA Double-Strand Breaks

作　　者：任来峰[1] 郭莲娣[2] 石新丽[3] 李莎[2] 

机构地区：[1]山西医科大学汾阳学院医学检验系,汾阳032200 [2]四川大学华西第二医院发育与干细胞研究所,成都610041 [3]河北中医学院微生物与免疫教研室,石家庄050200

出　　处：《中国细胞生物学学报》2014年第1期69-74,共6页Chinese Journal of Cell Biology

摘　　要：SMU1是一个与细胞基因组复制和RNA剪切过程相关的新基因。该研究为进一步调查SMU1对细胞增殖及DNA双链断裂(DNA double-strand breaks,DNA DSBs)损伤应答的影响,设计合成针对SMU1基因的小分子siRNA,并与对照siRNA(scramble)分别转染HEK 293T或U2OS细胞。通过免疫印迹(Western blot)检测证实,siSMU1转染细胞中SMU1的表达显著下降,采用台盼蓝染色细胞计数检测显示,SMU1表达下调显著降低细胞增殖能力。免疫荧光和免疫印迹法检测结果表明,SMU1表达下调显著增加细胞内源性DSBs损伤(γH2AX foci和蛋白水平均升高);而进一步用X-ray处理细胞造成外源性DSBs损伤后,SMU1沉默细胞显示出延长的DSBs损伤修复动力学(减缓的γH2AX foci和蛋白水平消退)。以上结果提示,SMU1在细胞DSBs损伤修复反应中扮演重要角色,积极参与细胞基因组完整性的维持。SMU1 is a novel gene, which implicated in both DNA replication and RNA splicing events. In this study, in order to investigate the role of SMU1 in cellular proliferation and response to DNA double-strand breaks （DSBs）, SMUl-specific siRNA was designed and synthesized, and SMU1 siRNA or control siRNA （scramble） was transfected into HEK 293T or U2OS cells, respectively. Western blot was used to assess the expression level of SMU1 and γH2AX; the cellular proliferation ability was determined by cell counting after trypan blue stains. After treating cells with X-ray, the recruitment of 7H2AX to DNA damage site was determined by immunofluorescence （IF）. The results showed that the expression of SMU1 protein was remarkably decreased in SMU1 siRNA- transfected cells, and knockdown of SMU1 in 293T cells caused obvious growth inhibition. The results also showed that down-regulation of SMU1 led to elevated endogenous DSBs （increased yH2AX foci and protein level） andprolonged DSBs repair kinetics （prolonged existence of the yH2AX foci and protein level） after treating cells with X-ray. Together, these results show that SMU1 plays an important role in the response of cells to DSBs damage and actively participates in the protection of genomic integrity.

关 键 词：DNA损伤 RNA干扰 DNA双链断裂 基因组稳定性 

分 类 号：Q78[生物学—分子生物学]