HBV影响XRN2基因在HepG2-H7细胞中表达的机制研究

目的利用稳定表达HBV的HepG2-H7细胞，研究HBV对XRN2基因表达的调控，并对其作用机制进行初步探讨。方法用RT—PCR和Real-time PCR的方法检测HepG2细胞及稳定表达HBV的HepG2-H7细胞中XRN2在mRNA水平的表达差异。构建XRN2启动子的萤火虫荧光素酶报告质粒，分别转染HepG2细胞及HepG2-H7细胞，检测HBV对XRN2启动子的影响。将XRN2启动子质粒与HBV4种蛋白的真核表达质粒共转染HepG2细胞，寻找对启动子影响较大的HBV蛋白。结果RT—PCR和Real-time PCR的结果显示XRN2在HepG2-H7细胞中的表达较HepG2细胞有所下降。荧光素酶活性分析显示HBV能抑制XRN2启动子的活性，且HBx和HBp蛋白在这一过程中起主要作用。结论HBV蛋白可以通过抑制XRN2启动子活性调节其在HepG2-H7细胞中的表达。

HBV Regulates XRN2 Expression Via Inhibition Its Promoter Activity in HepG2-H7 Cells

Objective To investigate the mechanism of HBV modulating the expression of XRN2. Methods RT-PCR and Real-time PCR were performed to check XRN2 mRNA expressions in HepG2 and HepG2-H7 cell lines, pGL3-XRN2-P, the XRN2 promoter luciferase reporter plas- mid, was constructed and transiently transfectcd into HepG2 and HepG2-H7 cells to analyze the in- fluence of HBV on XRN2 promoter activity. Then pGL3-XRN2-P were transiently transfected into HepG2 cells with HBx, HBs, HBp, HBc expression plasmids, respectively. The luciferase activi- ties were then detected. Results The expressions of XRN2 on mRNA level in HepG2-H7 ceils were lower than that in HepG2 cells. The luciferase activity assay demonstrated that HBV could suppress XRN2 promoter activity. Compared to the control group, the relative luciferase activities in HepG2 cells transfected with HBx and HBp expression plasmids decreased about 45% and 53% , corre- spondingly. Conclusion HBV downregulates XRN2 expression in HepG2-H7 ceils by inhibiting its promoter activity. HBx and HBp proteins might play important roles in this process.