WOODCHUCK HEPATITIS VIRUS NON-STRUCTURAL GENES

这项研究的长期目标是了解B型肝炎 乙型肝炎病毒（HBV）及其嗜肝DNA病毒科中的亲属引起疾病， 特别是慢性肝炎和肝细胞癌（HCC）。 土拨鼠肝炎病毒在遗传学上与HBV非常相似， 发病机制，引起慢性感染和HCC，并被用作 人类疾病的实验模型。 嗜肝DNA病毒基因组编码 对于四种类型的多肽，其中三种被认为是 病毒粒子的组成部分。 第四个基因，X，至今还没有已知的功能 在病毒复制中，但能够反式激活其他基因， 转染细胞，因此怀疑与 致癌作用 此外，首席研究员最近还 获得了WHV产生的新型剪接信使RNA的证据。 的 这种mRNA的遗传功能尚不清楚，但它可能参与 X蛋白或另一种尚未鉴定的基因的表达 产品 本项目旨在定义两者的功能 剪接的mRNA和X基因。 这种方法将是产生突变，破坏或修改 WHV X多肽和剪接mRNA的功能，通过 克隆的WHV DNA的位点特异性诱变。 突变的基因组将 转染到肝细胞系中，所述肝细胞系已知支持 传染性病毒，并测试结构完整病毒的产生。 用这种方法产生的突变病毒将在 通过接种到成年土拨鼠体内。 突变体被证明 将被接种到新生的土拨鼠，这将是 以确定他们发展慢性疾病的频率， 感染和随后的HCC。 这项研究项目将确定影响病毒的遗传因素， WHV的传染性和致病性。 这将提供深入了解 病毒复制的生物化学、免疫学和其他宿主因素， 以及毒力不同的病毒变体。 这些新知识将是 直接适用于治疗和预防HBV感染， 人类

The long-term objective of this research is to understand how hepatitis B virus (HBV) and its relatives in the family Hepadnaviridae cause disease, specifically chronic hepatitis and hepatocellular carcinoma (HCC). Woodchuck hepatitis virus closely resembles HBV in genetics and pathogenesis, causing both chronic infection and HCC, and is used as an experimental model for the human disease. The hepadnavirus genome codes for four types of polypeptides, three of which are accounted for as components of the virion. The fourth gene, X, has as yet no known function in virus replication, but is able to trans-activate other genes in transfected cells and is, therefore, suspected to be involved in carcinogenesis. In addition the Principal Investigator has recently obtained evidence for a novel spliced messenger RNA produced by WHV. The genetic function of this mRNA is not yet known, but it may be involved in the expression of the X protein or of another as yet unidentified gene product. This project is directed toward defining the functions of both the spliced mRNA and the X gene. The approach will be to generate mutations which destroy or modify the function of the X polypeptide of WHV and of the spliced mRNA, by means of site-specific mutagenesis of cloned WHV DNA. The mutated genomes will be transfected into liver cell lines which are known to support production of infectious virus, and tested for production of structurally complete virus. Mutant virus produced in this way will then be tested for infectivity in vivo by inoculation into adult woodchucks. Mutants that are thus proven to be infective will be inoculated into newborn woodchucks, which will be followed to determine the frequency with which they develop chronic infection and subsequently HCC. This research project will identify viral genetic factors that influence the infectivity and pathogenesis of WHV. This will provide insight into the biochemistry of virus replication, immunology and other host factors, and virus variants that differ in virulence. This new knowledge will be directly applicable to the treatment and prevention of HBV infection in humans.