DNA Replication and Gene Expression of Chlorella Viruses

描述(由申请人提供)：在过去的20年里，形成空斑的大型dsDNA小球藻病毒提供了新的和意想不到的基因产品，包括几种与医学相关的蛋白质。这项提议的目标是朝着了解这些病毒及其相关基因和基因产物的结构和功能方面的长期目标迈出了一步。许多小球藻病毒蛋白是其功能类别中最小的代表。因此，其中一些蛋白质是密集的物理和生化研究的对象，例如II型DNA拓扑异构酶和钾离子通道蛋白Kcv。这项建议侧重于与病毒进入细胞和子代病毒成熟相关的两个重要问题。这项建议的具体目的是：i)检测广泛的小球藻病毒的kcv基因及其相应的蛋白质，作为探索钾离子通道结构/功能关系的替代方法；ii)评估病毒编码的病毒主要衣壳蛋白Vp54的异常翻译后修饰。除了确定7种假定的病毒编码的糖基转移酶的特征外，还将确定附着在主要衣壳蛋白上的6种多糖的结构。这些病毒蛋白将在生理、分子生物学和生化水平上进行研究，包括结构分析。这些研究有望揭示钾离子通道分子内和分子间相互作用的新概念，以及蛋白质糖基化和肉豆蔻化的新机制。系统发育分析表明，遗传多样性但形态难以区分的小球藻病毒有很长的进化历史，可能可以追溯到真核生物和原核生物分离的时候。因此，小球藻病毒是研究大核质dsDNA病毒的重要模型，因为它们与重要的哺乳动物病毒，如痘病毒和检疫的非洲猪瘟病毒具有进化联系。

DESCRIPTION (provided by applicant): The large (>330 kb) dsDNA, plaque-forming chlorella viruses have provided new and unexpected gene products for the past 20 years, including several medically relevant proteins. The objectives of this proposal are a step toward the long-term goal of understanding the structural and functional aspects of these viruses, as well as their associated genes and gene products. Many chlorella virus proteins are the smallest representatives of their functional class. Consequently, some of these proteins are the subject of intense physical and biochemical investigation, e.g. a type II DNA topoisomerase and a potassium ion channel protein Kcv. This proposal focuses on two important problems associated with virus entry into the cell and maturation of progeny viruses. The specific aims of this proposal are to: i) examine kcv genes and their corresponding proteins from a broad range of chlorella viruses as an alternate approach for exploring structure/function relationships in potassium ion channels and ii) evaluate unusual virus-encoded posttranslational modifications of the virus major capsid protein, Vp54. In addition to characterizing the seven putative virus-encoded glycosyltransferases, the structures of the six glycans attached to the major capsid protein will be determined. The viral proteins will be investigated at physiological, molecular biological and biochemical levels, including structural analyses. These studies are expected to reveal new concepts in intra- and inter-molecular interactions of potassium ion channels, and also novel mechanisms for protein glycosylation and myristoylation. Phylogenetic analyses indicate the genetically diverse but morphologically indistinguishable chlorella viruses have a long evolutionary history, possibly dating back to the time eukaryotes and prokaryotes separated. Thus, chlorella viruses are an important model for studying large nucleocytoplasmic dsDNA viruses because they have evolutionary ties to important mammalian viruses, such as the pox viruses and the quarantined African swine fever virus.