Cyclin requirements in gammaherpesvirus infection and disease

描述（由申请人提供）：伽玛疱疹病毒在免疫缺陷个体中导致与恶性肿瘤和其他慢性疾病相关的终身感染。人类伽玛疱疹病毒包括爱泼斯坦·巴尔病毒和卡波西氏肉瘤相关病毒，它们与伯基特淋巴瘤、霍奇金淋巴瘤、移植后淋巴细胞增生性疾病、鼻咽癌、腹膜积液淋巴瘤和卡波西氏肉瘤有关。鉴于人类伽玛疱疹病毒严格的宿主特异性，一个主要的挑战是了解在健康和免疫受损个体体内调节伽玛疱疹病毒感染结果的宿主和病毒因素。本研究广泛利用小鼠γ疱疹病毒68，研究病毒和宿主基因在形成感染结果中的遗传贡献。通过我们之前的工作，我们对病毒基因（病毒周期蛋白）促进慢性感染的精确体内环境有了广泛的了解。我们确定了γ疱疹病毒感染和疾病的7个不同参数，包括依赖于病毒编码的细胞周期蛋白同源物的免疫缺陷模型。在这项资助中，我们将剖析病毒周期蛋白促进体内感染的分子途径，使用重组病毒，其中病毒周期蛋白已被替代的病毒或细胞周期蛋白所取代。我们将描述病毒周期蛋白在感染的所有周期蛋白依赖方面的活性，识别存在和不存在病毒周期蛋白的感染细胞库，并定义病毒周期蛋白在持续感染和潜伏期感染再激活中的分子机制。

DESCRIPTION (provided by applicant): Gammaherpesviruses result in lifelong infection associated with malignancies and other chronic disease in immune deficient individuals. The human gammaherpesviruses include Epstein Barr virus and Kaposi's Sarcoma associated virus, which are associated with Burkitt's lymphoma, Hodgkin's lymphoma, post-transplant lymphoproliferative disorder, nasopharyngeal carcinoma, peritoneal effusion lymphoma and Kaposi's sarcoma. Given the strict host specificity of the human gammaherpesviruses, a major challenge is to understand the host and viral factors that regulate the outcome of gammaherpesvirus infection in vivo, in both healthy and immune compromised individuals. This proposal makes extensive use of the mouse gammaherpesvirus 68, to investigate the genetic contribution of viral and host genes in shaping the outcome of infection. Through our previous work, we developed an extensive knowledge of the precise in vivo contexts in which a viral gene, the viral cyclin, promotes chronic infection. We identified seven different parameters of gammaherpesvirus infection and disease, including models of immune deficiency that are dependent on the virus encoded cyclin homolog. In this grant, we will dissect the molecular pathways used by the viral cyclin to promote infection in vivo, using recombinant viruses in which the viral cyclin has been replaced by alternate viral or cellular cyclins. We will characterize the viral cyclin activity in all cyclin dependent aspects of infection, identify the infected cell reservoir in presence and absence of the viral cyclin, and define the molecular mechanism of the viral cyclin in both persistent infection and reactivation from latency infection. These recombinant viruses reveal distinct, non-overlapping mechanisms of viral cyclin action. Moreover, since different cellular cyclins are able to substitute for distinct phases of the viral infection, comparing the biochemical properties of different cyclins in distinct contexts of infection will result in significant insights in gammaherpesvirus infection and disease. By integrating our unique in vivo insights into the viral cyclin with these recombinant viruses and our identification of the cellular target of the viral cyclin in virus reactivation, this grant wil combine biochemistry and genetics, with in vitro and in vivo models of infection to define new molecular pathways that promote gammaherpesvirus infection and pathogenesis in the whole animal. Further, we propose to test candidate inhibitors of viral cyclins and viral cyclin dependent functions both in vitro and in vivo. Finally, our demonstration that host cyclins can facilitate virus infection and that a specific host tumor suppressor can repress virus reactivation promises that our investigation of the virus encoded cyclins will advance the field of cancer biology beyond virus associated oncogenesis. These studies of the v-cyclin have, and will continue to yield fundamental insights into gammaherpesvirus infection and further elucidate new mechanisms by which gammaherpesvirus pathogenesis can be abrogated. PUBLIC HEALTH RELEVANCE: The cellular cyclins have been strongly associated with tumorigenesis since their discovery, and while they were initially considered exclusively for regulating cell proliferation, recent studies show that frequent overlap in the cell proliferation functions, yet that their roles in cell fate, development and differentiation are distinct. Our studies of the virus encoded cyclins have identified that these cyclins are required at several stages of infection and pathogenesis, and that they work by at least two different mechanisms and that one of these mechanisms functions to oppose the activity of a cellular tumor suppressor protein. The work proposed here will define the mechanism of the viral cyclins during authentic infection and disease and will identify potential interventions relevant to human inflammatory disease and malignancies, both those associated with gammaherpesvirus infection and related to cellular cyclins and tumor suppressors.