The role of structural plasticity in the norovirus capsid

项目摘要/摘要 动物病毒有两个重要特征：a)将它们的基因组传递给靶标的有效系统 细胞通常涉及病毒粒子的激活过程和b)与获得性免疫相互作用的一种方式 主机的系统。这里详细的结构和生物物理研究将显示诺如病毒是如何 进化的衣壳兼具这两种功能。 全球近五分之一的胃肠炎病例是由人类诺如病毒引起的。诺如病毒 每隔2-4年产生新的毒株，导致全球流行。仅在美国，每年就有~20个 100万例和7万多名儿童住院治疗。疫苗的努力因一种 缺乏关于抗体结合和抗体逃逸机制的详细结构信息。在……里面 此外，这种疾病的控制也是有问题的，因为只有10个病毒粒子就足以感染 正常的成年人。对于人类诺如病毒来说，理解所有这些过程都很困难，因为 缺乏组织培养系统和小动物模型。为此，我们将使用高度可驯服的 老鼠诺沃克病毒系统，我们有一个细胞培养系统和一个有感染性的克隆。 关于病毒衣壳的第一个功能，我们提出证据表明诺如病毒似乎经历了 一种明显的激活过程，其中胆盐的添加导致突出的结构域(P结构域) 旋转并移动到贝壳的表面上。这一运动与极大增强的 病毒与细胞的结合。关于病毒衣壳的第二个功能，我们也提出了证据 P结构域本身是高度可塑性的，这种运动性在受体结合和抗体中发挥着不可或缺的作用 逃走。因此，这里提出的研究不仅将阐明一种非常独特的诺沃克病毒激活 过程，但也包括病毒如何逃避免疫系统。总而言之，这些信息可以在 为这一严重疾病开发疫苗和疗法的未来。

Project Summary/Abstract Animal viruses share two important features; a) an efficient system for delivering their genome to the target cell usually involving an activation process in the virion and b) a means of interacting with the adaptive immune system of the host. The structural and biophysical studies detailed here will show how the noroviruses have evolved capsids that perform both functions. Human noroviruses are responsible for almost a fifth of all cases of gastroenteritis worldwide. Noroviruses generate new strains every 2-4 years that cause worldwide epidemics. In the US alone, annually there are ~20 million cases and more than 70,000 hospitalizations of children. Efforts for a vaccine have been hindered by a lack of detailed structural information about antibody binding and the mechanisms of antibody escape. In addition, containment of the disease is also problematic since as few as ten virions are sufficient to infect a normal adult. Understanding all of these processes has been difficult with human noroviruses because of the lack of a tissue culture system and small animal model. To this end, we will be using the highly tractable mouse norovirus system where we have a cell culture system and an infectious clone. With regard to the first function of a viral capsid, we present evidence that noroviruses appear to undergo an apparent activation process where the addition of bile salts causes the protruding domain (P domain) to rotated and move ~16Å onto the surface of the shell. This movement is correlated with greatly enhanced binding of the virus to the cell. In terms of the second function of a viral capsid, we also present evidence that the P domain itself is highly plastic and that this motility plays an integral role in receptor binding and antibody escape. Therefore, the studies presented here will not only elucidate a very unique norovirus activation process, but also how the virus evades the immune system. Together, this information could be leveraged in the future to develop vaccines and therapeutics for this serious disease.