乙型肝炎病毒X蛋白结合蛋白（HBXIP）对细胞周期的影响

与乙肝病毒X蛋白（HBX）的C端结合，它具有抑制HBX活性的作用. 为进一步阐明HBXIP对细胞增殖的作用及其分子机制，构建了HBXIP的真核表达载体，并将其稳定转染至正常人肝细胞系L-O2细胞中，建立了稳定表达HBXIP蛋白的肝细胞系，命名为L-O2-hbxip. 然后，应用MTT、BrdU标记实验和流式细胞术等方法，发现HBXIP过表达后,L-O2细胞的生长速度明显加快，可促进细胞由G₁期进入到S期，表明HBXIP具有促进L-O2-hbxip细胞增殖的作用.应用免疫印迹对有关细胞周期相关蛋白进行了检测. 结果显示，HBXIP过表达时可上调细胞周期蛋白D₁、细胞周期蛋白E的表达，并下调p21和p27的表达，从而调节细胞周期，产生对细胞增殖的影响.

Effect of Hepatitis B Virus X-interacting Protein (HBXIP) on Cell Cycle

Hepatitis B virus X-interacting protein(HBXIP)was found by binding with C-terminal of hepatitis B virus X(HBX),and down-regulated the activity of HBX.To further investigate the effects of HBXIP on proliferation of the cell and its molecular mechanism,we constructed the eukaryotic vector of expressing HBXIP,termed pCMV-hbxip,which was stably transfected into human normal hepatic L-O2 cells,named L-O2-hbxip.Both MTT assay and BrdU incorporation assay demonstrated that the growth rate of L-O2-hbxip cell was increased compared with control group,the results from FCM assay showed in L-O2-hbxip cells,the number of G_1 phase was significantly reduced while S phase was enhanced,respectively,suggesting that HBXIP promote the cell proliferation.Furthermore,the proteins involving in cell cycle regulation were examined by Western blot analysis.Western blot results showed that HBXIP was able to promote cell cycle progression via up-regulating cyclin D_1 and cyclin E,and down-regulating p21 and p27.