REGULATION OF HEPATITIS B VIRUS TRANSCRIPTION

据估计，慢性乙肝病毒感染仍然是一个主要的临床问题 世界上多达5亿的慢性乙肝病毒携带者， 到目前为止，还没有可靠的治疗方法。慢性病的后果 乙肝病毒感染可包括使人衰弱的慢性活动性肝炎、肝脏 肝硬变和原发性肝细胞癌是主要原因 死亡的威胁。乙肝病毒通过病毒的逆转录进行复制 由HBVDNA基因组编码的前基因组RNA。因此， 病毒基因组的转录是病毒的关键步骤。 复制。因此，长期目标是理解 乙肝病毒协同调控和差异化调控机制的研究 转录，以及它们对体内病毒生物合成的影响 病毒转录过程中的关键步骤可能是 被确定为抗病毒药物破坏的目标。基于 对转录因子的了解，这些转录因子在 在瞬时转染法分析中调节乙肝病毒转录 报告基因的构建，转录水平从大到小 主要的表面抗原启动子将在 病毒全基因组及其对病毒转录本、抗原的影响 本课程将研究病毒的生产、复制和生物合成。 具体地说，为了重现肝脏的作用 在乙肝转基因小鼠中观察到病毒复制的再生 解除HNF1与大分子表面抗原结合的效果 将检查启动子是否减少了2.4kb的RNA合成，以及 特定复制中间体的外观，特别是非复制中间体 封装的无蛋白RC和CCC HBVDNA。将对小鼠进行检查，以确定 将这些HBVDNA复制中间产物整合到宿主体内 染色体DNA，一种与原发肿瘤发育有关的事件 人肝细胞癌。提示肝脏特异的 体内观察到的HBV2.1kb转录本的表达 细胞培养是由于HNF3与HNF3结合部位相互作用所致 位于主要表面抗原启动子将被检测。这个 解释这种差异的有利机制假设HNF3是 需要在体内改变启动子的局部染色质结构 以允许近端的启动子区域被泛在的 转录因子，随后激活转录从 推动者。该机制将直接通过功能测试和 活体足迹分析。

Chronic HBV infection remains a major clinical problem with estimates of as many as 500 million HBV chronic carriers in the world for whom, to date, there is no reliable treatment. The consequences of chronic HBV infection can include debilitating chronic active hepatitis, liver cirrhosis, and primary hepatocellular carcinoma which are major causes of mortality. HBV replicates by reverse transcription of the viral pregenomic RNA encoded by the HBV DNA genome. Consequently, transcription of the viral genome is an essential step in virus replication. Therefore, the long term objective is to understand the mechanisms controlling the coordinate and differential regulation of HBV transcription, and their influence on viral biosynthesis in vivo, so that critical steps in the viral transcription process might be identified and targeted for disruption by antiviral agents. Based on the knowledge of the transcription factors which are important in regulating HBV transcription in transient transfection analysis using reporter gene constructs, the levels of transcription from the large and major surface antigen promoters will be altered in the context of the complete viral genome and the effects on viral transcripts, antigen production, replication, and viral biosynthesis will be examined. Specifically, in an attempt to reproduce the effect of liver regeneration on viral replication observed in HBV transgenic mice, the effect of eliminating the binding of HNF1 to the large surface antigen promoter will be examined for reduced 2.4kb RNA synthesis and the appearance of specific replication intermediates, in particular non- encapsidated protein-free RC and CCC HBV DNA. Mice will be examined for the integration of these HBV DNA replication intermediates into the host chromosomal DNA, an event associated with the development of primary hepatocellular carcinoma in man. The suggestion that the liver-specific expression of the HBV 2.1kb transcript observed in vivo but absent in cell culture is due to HNF3 interacting with the HNF3 binding site located in the major surface antigen promoter will be examined. The favored mechanism accounting for this difference assumes that HNF3 is required to alter the local chromatin structure of the promoter in vivo to permit the proximal promoter region to be occupied by ubiquitous transcription factors which subsequently activate transcription from the promoter. This mechanism will be tested directly by functional and in vivo footprinting analysis.