Cyclin requirements in gammaherpesvirus infection and disease

描述(申请人提供)：在免疫缺陷个体中，伽玛疱疹病毒会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Epstein Barr病毒和Kaposi肉瘤相关病毒，它们与Burkitt淋巴瘤、霍奇金淋巴瘤、移植后淋巴增生性疾病、鼻咽癌、腹膜渗出性淋巴瘤和Kaposi肉瘤有关。鉴于人类伽马疱疹病毒具有严格的宿主特异性，一个主要的挑战是了解宿主和病毒因素在体内调节伽马疱疹病毒在体内感染的结果，无论是在健康还是免疫受损的个体中。这项建议广泛使用小鼠伽马疱疹病毒68，以调查病毒和宿主基因在塑造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体内精确环境有了广泛的了解。我们确定了七种不同的伽马疱疹病毒感染和疾病参数，包括依赖于病毒编码的细胞周期蛋白同源基因的免疫缺陷模型。在这项资助中，我们将使用重组病毒剖析病毒周期蛋白在体内促进感染的分子途径，在重组病毒中，病毒周期蛋白已被交替的病毒或细胞周期蛋白取代。我们将描述病毒周期蛋白在感染的所有依赖于细胞周期蛋白的方面的活性，确定存在和不存在病毒周期蛋白的感染细胞库，并确定病毒周期蛋白在持续感染和潜伏感染重新激活中的分子机制。 这些重组病毒揭示了病毒周期蛋白作用的不同的、非重叠的机制。此外，由于不同的细胞周期蛋白能够替代病毒感染的不同阶段，比较不同细胞周期蛋白在不同感染环境中的生化特性将导致对伽马疱疹病毒感染和疾病的重大洞察。通过将我们在体内对病毒周期蛋白的独特见解与这些重组病毒结合起来，以及我们对病毒周期蛋白在病毒重新激活中的细胞靶点的确定，这项赠款将结合生物化学和遗传学，以及体外和体内感染模型，以确定促进整个动物中伽马疱疹病毒感染和发病的新的分子途径。此外，我们建议在体外和体内测试病毒周期蛋白的候选抑制剂和病毒周期蛋白依赖功能。最后，我们证明了宿主细胞周期蛋白可以促进病毒感染，以及特定的宿主肿瘤抑制因子可以抑制病毒的重新激活 我们承诺，我们对病毒编码的细胞周期蛋白的研究将推动癌症生物学领域超越病毒相关的肿瘤发生。这些对v-Cyclin的研究已经并将继续产生对伽马疱疹病毒感染的基本见解，并进一步阐明可以废除伽马疱疹病毒发病机制的新机制。 公共卫生相关性：自从发现细胞周期蛋白以来，它们一直与肿瘤的发生密切相关，虽然最初被认为是专门调节细胞增殖的，但最近的研究表明，细胞增殖功能经常重叠，但它们在细胞命运、发育和分化中的作用是不同的。我们对病毒编码的细胞周期蛋白的研究发现，这些细胞周期蛋白在感染和发病的几个阶段都是必需的，它们至少通过两种不同的机制发挥作用，其中一种机制起作用的是对抗细胞肿瘤抑制蛋白的活性。这里提出的工作将确定病毒周期蛋白在真实感染和疾病过程中的机制，并将确定与人类炎症性疾病和恶性肿瘤相关的潜在干预措施，包括与伽马疱疹病毒感染相关的干预措施，以及与细胞周期蛋白和肿瘤抑制因子相关的干预措施。

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.