中文摘要：

目的探讨泛素连接酶Ring2在苯并[a]芘（B[a]P）致细胞DNA损伤中的作用。方法采用RNA干扰方法降低人支气管上皮细胞（16HBE）Ring2表达。以0、1、2,4、8、16、32μmol／LB[a]P染毒16HBE和siRNA—Ring2细胞24h；以16μmol／LB[a]P染毒16HBE和siRNA—Ring2细胞0、1、2、4、8、12、24h。染毒结束后采用碱性单细胞凝胶电泳法检测DNA损伤水平。结果采用RNAi36h后，目的基因Ring2的表达量与正常细胞相比下降了72％，达到后续实验要求。经协方差分析，分组因素和染毒浓度都对Olive尾矩值有影响，P=0．032和P〈0．001。正常细胞和siRNA—Ring2细胞组的修正均数相比，siRNA—Ring2组OTM明显高于正常细胞组；分组因素（是否进行RNAi）和染毒时间都对Olive尾矩值有影响，P=0．031和P〈0．001。正常细胞和siRNA—Ring2细胞组的修正均数相比，siRNA-Ring2组Olive尾矩明显高于正常细胞组。结论Ring2低表达的细胞DNA对B[a]P的敏感性增加，可能与降低Ring2表达后致H2A单泛素化水平降低有一定关系。

英文摘要：

Objective To investigate the role of ubiquitin ligase Ring2 in the DNA damage induced by benzo[a]pyrene （B[a]P）. Methods The expression of Ring2 in human bronchial epithelial （16HBE） cells was inhibited by small interfering RNA （siRNA） to obtain siRNA-Ring2 16HBE cells. The siRNA-Ring2 16HBE cells, as well as normal 16HBE cells, were exposed to B[a]P （0, l, 2, 4, 8, 16, and 32μmol/L） for 24 h; other siRNA-Ring2 16HBE cells and normal 16HBE cells were exposed to B [alP （ 16 μmol/L） for 0, 1, 2, 4, 8, 12, and 24 h. The levels of DNA damage were evaluated by alkaline single cell gel electrophoresis assay. Results After being treated with siRNA for 36 h, the siRNA-Ring2 16HBE cells showed a 72% decrease in Ring2 expression compared with normal 16HBE cells. The analysis of covariance showed that whether to be treated with siRNA and concentration of B[a]P had impacts on Olive tail moment （OTM） （P=0.032 and P〈0.001 ）; the adjusted mean of OTM was significantly higher in siRNA-Ring2 16HBE cells than in normal 16HBE cells. Whether to be treated with siRNA and B[a]P exposure time had impacts on OTM （P=0.031 and P〈0.001 ）; the adjusted mean of OTM was significantly higher in siRNA-Ring2 16HBE cells than in normal 16HBE cells. Conclusion The DNA of 16HBE cells with decreased Ring2 expression has increased susceptibility to B[a]P, which may be due to reduced H2A monoubiquitination following decrease in Ring2 expression.