FUNCTIONAL ASPECTS OF HEPATITIS B VIRUS X-PROTEIN

HBV X蛋白已被证明对HBV DNA有反式激活作用。 多种病毒和细胞基因的表达。的表达 在瞬时表达系统中研究了肿瘤抑制基因RB， 将HBV X基因转染Hep G2细胞。 HBV X开放阅读框架 通过PCR从含有野生型HBV DNA的质粒产生， 插入到表达载体中。用质粒pHBV-X 切除人肝母细胞瘤细胞系Hep G2。提取蛋白质 DNA转染后48小时。内源性RB蛋白水平为 通过使用RB单克隆抗体的蛋白质免疫印迹分析。RB 未转染蛋白的Hep G2细胞和用载体转染的Hep G2细胞 也作为对照进行分析。重组质粒pHBV-X中RB蛋白的表达水平 转染的Hep G2细胞与对照相比增加了近10倍 细胞RB之间的初步体外免疫共沉淀研究 蛋白和HBV X蛋白之间没有直接的相互作用 和HBV X蛋白。乙型肝炎病毒X基因可以改变肝细胞的功能， RB肿瘤抑制基因的表达表明， X基因在HBV介导的肝癌发生中的作用 工作继续努力 以确定X蛋白的反式激活机制。宿主介导 将分析与X基因活动有关的转录因子 通过X-蛋白反式激活作用在不同的肝和非肝 细胞系

HBV X protein has been shown to have a transactivating effect on the expression of a variety of viral and cellular genes. The expression of tumor suppressor gene RB was studied in a transient expression system by transfecting HBV X gene into Hep G2 cells. The HBV X open reading frame was generated by PCR from plasmid containing wild type HBV DNA and was inserted into expression vector. The plasmid pHBV- X was used to transfect Hep G2, a human hepatoblastoma cell line. Protein was extracted 48 hours after DNA transfection. The level of endogenous RB protein was analyzed by western immunoblotting using RB monoclonal antibody. RB protein untransfected Hep G2 cells and Hep G2 transfected with vector alone were also analyzed as controls. The level of RB protein in pHBV-X transfected Hep G2 cells increased nearly 10-fold compared to the control cells. Preliminary in vitro co-immunoprecipitation studies between RB protein and HBV X protein do not indicate direct interaction between RB and HBV X proteins. The finding that HBV derived X gene can alter the expression of RB tumor suppressor gene suggest a possible role for the X gene in HBV mediated hepatocarcinogenesis. Work continues in an effort to determine the mechanism of transactivation by X protein. Host mediated transcriptional factor(s) involved in X- gene activities will be analyzed by X-protein transactivation effect in different hepatic and non hepatic cell lines.