Forward genetic prediction and testing of virulence loci in herpes simplex virus 1

项目摘要 单纯疱疹病毒1（HSV-1）和HSV-2引起数百万慢性感染。这些病毒导致 上皮性口腔“冷”疮和生殖器病变，由于潜伏病毒的重新激活， 储存在神经元中。HSV-1感染的临床结果是高度多样化的，从表面 从复发率完全不同的病变，到无症状脱落，到严重和潜在致命的 脑炎这种变异被认为是由多种因素引起的，包括病毒遗传 差异，人类遗传易感性和环境变量。动物模型作为 这是我们对HSV-1疾病体内分子理解的基石，并提供了一个机会， 剖析病毒遗传对发病机制的贡献，同时控制宿主遗传因素， 环境变量。 我们最近对一组HSV-1低传代临床分离株进行了测序，并对每种分离株进行了分类。 根据其在小鼠眼部感染模型中可再现毒力表型分离。我们 在这个模型中，通过病毒感染、复制和诱导致死性疾病的能力来衡量毒力， 涉及病毒在眼表开始感染，迁移到周围神经系统， （三叉神经节），甚至渗透到中枢神经系统（CNS）。使用多个 通过统计学方法，我们在病毒被膜蛋白VP 22（UL 49）中发现了两个位点， 区分高毒力临床分离株和低毒力分离株。VP 22是一种病毒被膜蛋白 它在α-疱疹病毒中是保守的，作为病毒和细胞蛋白的中心发挥作用。 交互. VP 22的功能与病毒反式激活蛋白VP 16（UL 48）密切相关， 病毒RNA酶VHS（UL 41）。检测到的与鼠毒力相关的变异基因座存在于 在我们迄今为止调查的临床HSV-1分离株中的频率约为50%，表明 从这些实验中收集的知识将提供与正在进行的研究相关的病毒变体的数据。 抗病毒药物和疫苗的试验。 随着更多基因型-表型数据的增加，我们将使用全基因组关联 GWAS研究（GWAS）来测量VP 22和其他候选基因座与HSV-1毒力的关联。我们 将制备重组HSV-1菌株，以测试VP 22和其他候选毒力基因座在HSV-1中的作用， 体内和体外。我们将检验体内毒力和非毒力表型由以下原因引起的假设： 这些分离株之间VP 22的明显生化差异。这些实验的数据将使 我们测试我们的HSV-1毒力基因座的正向遗传预测的鲁棒性。如果这些数据可以 与未来人类的影响有关，根据病毒的毒性水平来衡量可能的毒性水平的能力 基因型将为未来的诊断和临床结果的预测提供有力的工具。

Project Summary Herpes simplex virus 1 (HSV-1) and HSV-2 cause millions of chronic infections. These viruses cause epithelial oral “cold” sores and genital lesions, which recur lifelong due to reactivation from a latent viral reservoir in neurons. Clinical outcomes from HSV-1 infection are highly diverse, ranging from surface lesions with quite different rates of recurrence, to asymptomatic shedding, to severe and potentially lethal encephalitis. This variation is thought to be caused by a combination of factors, including viral genetic differences, human genetic predisposition, and environmental variables. Animal models serve as the cornerstone of our molecular understanding of HSV-1 disease in vivo, and provide an opportunity to dissect viral genetic contributions to pathogenesis, while controlling for host genetic factors and environmental variables. We have recently sequenced a collection of low-passage clinical isolates of HSV-1 and categorized each isolate according to its reproducible virulence phenotype in a mouse ocular model of infection. We measured virulence in this model by the virus' ability to infect, replicate, and induce lethal disease, which involved the virus initiating infection at the ocular surface, migrating to the peripheral nervous system (trigeminal ganglia), and even penetrating into the central nervous system (CNS). Using multiple statistical approaches, we found two loci in the viral tegument protein VP22 (UL49) that predictably distinguish high-virulence clinical isolates from low-virulence isolates. VP22 is a viral tegument protein that is conserved among alpha-herpesviruses, which functions as a hub of viral and cellular protein interactions. VP22 functions in close concert with the viral transactivator protein VP16 (UL48), and the viral RNAse VHS (UL41). The variant loci detected in association with murine virulence exist at a frequency of approximately 50% in the clinical HSV-1 isolates we have surveyed to date, suggesting that knowledge gleaned from these experiments will provide data on viral variants of relevance to ongoing trials for antivirals and vaccines. With increased power from additional genotype-phenotype data, we will use a genome-wide association study (GWAS) to measure the association of VP22 and other candidate loci with virulence in HSV-1. We will make recombinant HSV-1 strains to test the role(s) of VP22 and other candidate virulence loci both in vivo and in vitro. We will test the hypothesis that virulent and non-virulent phenotypes in vivo result from distinct biochemical differences in VP22 between these isolates. Data from these experiments will enable us to test the robustness of our forward genetic predictions of virulence loci in HSV-1. If these data can be linked to human impacts in the future, the ability to gauge likely virulence level based on viral genotype would provide a powerful tool for future diagnostics and prediction of clinical outcomes.