Mechanisms of Avian Hepadnavirus Replication

禽肝炎病毒复制机制

• 批准号: 7357484
• 负责人: DANIEL D LOEB
• 金额: $ 33.3万
• 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 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7357484
• 关键词: 3' Splice Site; Base Pairing; Birds; Chronic; Cis-Acting Sequence; DNA; DNA biosynthesis; DNA chemical synthesis; Duck Hepatitis B Virus; Ducks; Genome; Genomics; Glycine decarboxylase; Hepadnaviridae; Hepatitis B Virus; Hepatocyte; Human; In Situ; Individual; Infection; Kinetics; Laboratories; Life Cycle Stages; Malignant Neoplasms; Malignant neoplasm of liver; Messenger RNA; Molecular Conformation; Nucleic Acids; Nucleotides; Oncogenic Viruses; Play; Proteins; RNA; RNA Splicing; Role; S cerevisiae SWI3 protein; Series; Simian B disease; Specificity; Structure; Variant; Viral; Virus; Virus Replication; Work; insight; viral RNA

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）是最流行的人类肿瘤病毒。据估计，慢性乙型肝炎病毒感染每年导致 1,000,000 例肝癌。乙型肝炎病毒必须在肝细胞内积极复制才能维持其慢性感染。我们致力于了解乙型肝炎病毒如何执行复制其基因组的各个步骤，以便了解该病毒如何导致人类癌症。迄今为止，对嗜肝DNA病毒DNA复制的大部分了解都是通过对禽嗜肝DNA病毒、鸭乙型肝炎病毒(DHBV)的研究得出的。在过去的十年中，我们的实验室通过 DHBV 的研究，为了解肝炎病毒 DNA 复制做出了多项贡献。我们最近的研究出现了一个普遍的主题：病毒基因组核酸的动态构象对其自身的复制做出了多种贡献。我们的分析阐明了禽嗜肝DNA病毒正链合成过程中有助于模板转换的两个基本机制：1）小DNA发夹抑制原位引发，因此有助于引物易位； 2) 三个顺式作用序列 3E、M 和 5E 之间的碱基配对有助于正链模板转换，大概是通过并置供体和受体模板进行引物易位和环化。此外，我们还发现了 DHBV 支持未剪接和剪接 RNA 同时积累的机制。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。该提案有三个目的：1）了解负链DNA第四个核苷酸合成后模板转换的机制； 2) 确定病毒P蛋白是否对正链模板转换做出特定贡献； 3)了解剪接RNA在DHBV生命周期中的作用。