Initiation of Hepatitis B Virus Replication

乙型肝炎病毒复制的启动

• 批准号: 6771037
• 负责人: Alan McLachlan
• 金额: $ 9.39万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6771037
• 关键词: Hepadnaviridae; cancer risk; gene mutation; hepatitis B; hepatitis B virus group; liver disorder; tissue /cell culture; virus DNA; virus RNA; virus genetics; virus infection mechanism; virus replication

DESCRIPTION (provided by applicant): Hepatitis B virus (HBV) infection is a worldwide health problem. It is estimated that there are 200 to 500 million HBV chronic carriers in the world for whom, to date, there is no reliable treatment. HBV causes both acute and chronic liver disease and the estimated relative risk of primary hepatocellular carcinoma (PHC) in chronic HBV carriers is approximately 100 times greater than in uninfected individuals. Therefore, effective treatments for chronic HBV infection are required. In these studies, the mechanism(s) regulating the initial steps in the synthesis of hepatitis B virus (HBV) DNA will be investigated. HBV DNA synthesis is initiated by binding of the viral polymerase to a stem-loop structure, epsilon, located at the 5'-end of the HBV pregenomic RNA. Initially, the first three nucleotides of HBV minus-strand DNA are synthesized utilizing the amino-terminal domain of the polymerase as a primer and the bulge region of epsilon as a template. The HBV polymerase with the covalently attached trinucleotide sequence is subsequently translocated to the DR1 sequence at the 3'-end of the pregenomic RNA. HBV minus-strand DNA synthesis then proceeds by the reverse transcription of the pregenomic RNA. The mechanism(s) regulating the translocation step are unknown. Recently, a regulatory sequence element, phi, located immediately upstream of the DR1 sequence at the 3'-end of the pregnomic RNA that is important for efficient viral replication and is complementary to the 5'-half of epsilon was identified. This finding suggests that the translocation of the minus-strand primer from epsilon to DR1 might be mediated by a conformational change in the pregenomic RNA that brings the primer into proximity with the DR1 sequence at the 3'-end of the pregenomic RNA. The conservation of the complementarity between epsilon and phi in the woodchuck hepatitis virus (WHV) and the duck hepatitis B virus (DHBV) genomes also supports this contention. Therefore, the role of the complementarity between epsilon and phi in regulating HBV replication will be examined directly by mutational analysis of these sequence elements. This approach is aimed at identifying possible targets for therapeutic intervention in chronic HBV infection.

描述（由申请人提供）：乙型肝炎病毒（HBV）感染是一个世界性的健康问题。 据估计，全世界有200至5亿乙肝慢性携带者，迄今为止尚无可靠的治疗方法。 HBV 可引起急性和慢性肝病，慢性 HBV 携带者患原发性肝细胞癌 (PHC) 的相对风险估计比未感染者高约 100 倍。 因此，需要针对慢性乙型肝炎病毒感染进行有效的治疗。 在这些研究中，将研究调节乙型肝炎病毒 (HBV) DNA 合成初始步骤的机制。 HBV DNA 合成是通过病毒聚合酶与位于 HBV 前基因组 RNA 5' 端的茎环结构 epsilon 结合而启动的。 最初，利用聚合酶的氨基末端结构域作为引物以及ε的凸出区域作为模板合成HBV负链DNA的前三个核苷酸。 具有共价连接的三核苷酸序列的 HBV 聚合酶随后易位至前基因组 RNA 3' 端的 DR1 序列。 然后，HBV 负链 DNA 合成通过前基因组 RNA 的逆转录进行。 调节易位步骤的机制尚不清楚。 最近，鉴定了一个调控序列元件phi，它位于基因组RNA 3'端DR1序列的紧邻上游，对有效病毒复制很重要，并且与epsilon的5'端互补。 这一发现表明，负链引物从ε到DR1的易位可能是由前基因组RNA的构象变化介导的，该构象变化使引物与前基因组RNA 3'端的DR1序列接近。 土拨鼠肝炎病毒 (WHV) 和鸭乙型肝炎病毒 (DHBV) 基因组中 epsilon 和 phi 之间互补性的保守性也支持了这一论点。 因此，epsilon和phi之间的互补性在调节HBV复制中的作用将通过这些序列元件的突变分析来直接检验。 该方法旨在确定慢性乙型肝炎感染治疗干预的可能目标。