乙型肝炎病毒X基因对痉挛性截瘫蛋白21表达的影响

Effect of hepatitis B virus X gene on the expression of spastic paraplegia 21

目的探讨HBVX基因对痉挛性截瘫蛋白（SPG）21表达的影响。方法采用RT—PCR和Westernblot检测HepG2和HepG2．2．15细胞mRNA和蛋白表达的差异，将带有SPG21基因启动子的报告质粒pGL3-SPG21分别与表达HBV基因组的单个基因的质粒共转染HepG2细胞，测定荧光色素酶的活性，以相对光单元（RUL）表达；RT—PCR和Westernblot分别检测SPG21mRNA和蛋白表达的变化。组间比较采用t检验。结果HepG2．2．15细胞中SPG21mRNA和蛋白的表达水平明显高于HepG2细胞，相对表达量（与β-肌动蛋白的灰度比值）为0．36±0．06对比0．21±0．05，P〈0．05。转染pCMVS、pCMV—E、pCMV—C、pCMV—X、pCMV—P和pCMV—ag2B后的HepG2细胞中，荧光素酶的活性分别为每微克蛋白（86±12）RUL、（75±12）RUL、（69±11）RUL、（875±27）RUL、（104±16）RUL和（67±12）RUL；与转染pCMV-tag2B组细胞相比，转染X基因者荧光素酶活性明显升高（P〈0．01）。HBVX基因在mRNA和蛋白水平上调SPG21的表达，这种激活作用随着X基因浓度的增加而增强。结论HBVX基因能特异性地激活SPG21的表达。

Objective To investigate the effect of hepatitis B virus（HBV） X gene on the expression of SPG21. Methods The expressions of SPG21 mRNA and protein in HepG2 and HepG2.2.15 cells were tested by RT-PCR and western blot. HepG2 cells were co-transfected with reporter plasmid pGL3-SPG21 and plasmids carrying individual genes of HBV, the luciferase activity was measured and the expressions of SPG21 were detected by RT-PCR and western blot. Results The expressions of SPG21 mRNA and protein were higher in HepG2.2.15 cells than in HepG2 cells （0.36 ± 0.06 vs 0.21 ± 0.05, P 〈 0.05）. The activity of SPG21 in HepG2 cells transfected with pCMV-X was higher （875 ± 27 vs 67 ± 12, P 〈 0.01） as compared to blank control group （transfected with pCMV-tag2B）. HBV X gene enhanced SPG21 gene promoter activity, SPG21 mRNA expression and SPG21 protein production in HepG2 cells in a dose-dependent manner. Conclusions HBV X gene can specially activate SPG21 expression.