Mechanisms of Avian Hepadnavirus Replication

禽肝炎病毒复制机制

• 批准号: 7009237
• 负责人: DANIEL D LOEB
• 金额: $ 34.99万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7009237
• 关键词: DNA replication; RNA splicing; cell line; duck hepatitis B virus; ducks; gene deletion mutation; genetic regulatory element; liver cells; messenger RNA; virus DNA; virus RNA; virus genetics; virus protein; virus replication

DESCRIPTION (provided by applicant): Hepatitis B virus (HBV) is the most prevalent human tumor virus. It is estimated that chronic HBV infection causes 1,000,000 cases of liver cancer annually. HBV must actively replicate within liver cells to maintain its chronic infection. We work to understand how HBV carries out the individual steps by which it replicates its genome in order to understand how this virus contributes to human cancer. To date, most insights into hepadnavirus DNA replication have come through the study of the avian hepadnavirus, duck hepatitis B virus (DHBV). Over the past decade, our laboratory has made multiple contributions to the understanding of hepadnavirus DNA replication through the study of DHBV. A general theme has emerged from our studies recently: the dynamic conformation of the viral genomic nucleic acid makes multiple contributions to its own replication. Our analyses have elucidated two fundamental mechanisms that contribute to the template switching during avian hepadnavirus plus-strand synthesis: 1) a small DNA hairpin suppresses in situ priming, and therefore contributes to primer translocation; and 2) base pairing between the three cis-acting sequences 3E, M, and 5E contributes to both plus-strand template switches, presumably by juxtaposing the donor and acceptor templates for primer translocation and circularization. In addition, we discovered the mechanism by which DHBV supports the simultaneous accumulation of unspliced and spliced RNA. An RNA secondary structure that contains the 5' and 3' splice sites suppresses splicing to permit the accumulation of pgRNA. This proposal has three aims: 1) to understand the mechanism of the template switch after the synthesis of the fourth nucleotide of minus-strand DNA; 2) to determine whether the viral P protein makes specific contributions to plus-strand template switching; and 3) to understand the role of the spliced RNA in the life cycle of DHBV.

描述（由申请人提供）：乙型肝炎病毒（HBV）是最普遍的人类肿瘤病毒。据估计，慢性HBV感染每年引起1,000,000例肝癌。 HBV必须在肝细胞内积极复制以维持其慢性感染。我们努力了解HBV如何进行复制基因组的单个步骤，以了解该病毒如何对人类癌症有效。迄今为止，大多数对肝DNA复制的见解是通过研究禽肝病毒，鸭乙型肝炎病毒（DHBV）的研究。在过去的十年中，我们的实验室通过研究DHBV为理解肝DNA复制做出了多种贡献。最近我们的研究中出现了一个一般主题：病毒基因组核酸的动态构象对其自身的复制产生了多种贡献。我们的分析已经阐明了两种基本机制，这些机制有助于在禽肝病毒加链合成期间的模板切换：1）一个小的DNA发夹抑制原位启动，因此有助于引物易位； 2）三个顺式作用序列3E，M和5E之间的基础配对有助于两个链模板开关，大概是通过将供体和受体模板并置用于引物易位和循环的。此外，我们发现了DHBV支持未贴合和剪接的RNA的机制。包含5'和3'剪接位点的RNA二级结构抑制剪接以允许PGRNA的积累。该提案具有三个目的：1）理解在减去链DNA的第四个核苷酸后，了解模板开关的机理； 2）确定病毒P蛋白是否对加链模板切换做出了特定的贡献； 3）了解剪接的RNA在DHBV生命周期中的作用。