Structural investigations of the alphaviral lifecycle

描述(申请人提供)：甲型病毒可以是严重的，有时是致命的，属于Togaviridae家族的人类病原体。只有甲型病毒和核型病毒被归类为TogaVirus。甲型病毒群广泛分布在全球各地，除南极洲外，甲型病毒属的各种成员已在每一块大陆上分离到。大约有27种不同的甲型病毒能够感染各种脊椎动物，如人、马和啮齿动物。根据它们的分布和引起的症状，甲型病毒可以进一步归类为包括欧洲、亚洲、澳大利亚和非洲的旧世界或包括美洲的新世界。甲型病毒在个体和物种之间的传播主要通过蚊子进行，这使得甲型病毒成为节肢动物传播病毒的成员。疾病可表现为两种一般形式中的一种，具体取决于病毒类型。东半球病毒(即基孔肯雅病毒、罗斯河病毒和辛德比斯病毒)的症状包括发烧、皮疹和关节痛。新世界病毒(即东部、西部和委内瑞拉马脑炎病毒)在高达15%的感染中出现发烧、不适、头痛和脑炎，儿童的发病率较高。目前，还没有有效的疫苗或药物来治疗 感染甲型病毒的人。因此，更好地了解甲型病毒的结构和功能将有助于开发安全有效的疫苗。该项目的总体目标是从结构上确定甲型病毒生命周期中涉及的步骤。感染的症状包括发烧、皮疹、头痛，有时还会出现脑炎。今天，还没有针对甲型病毒感染的有效疫苗。我们将使用委内瑞拉马脑炎病毒(VEEV)疫苗株TC-83通过冷冻电子显微镜和X射线结晶学获得病毒及其相关表面蛋白的原子分辨结构。通过使用中和抗体，我们将病毒捕获在病毒生命周期的中间阶段，随后对病毒：抗体复合体进行结构分析，以描绘病毒组装、感染和成熟所需的复杂构象变化。这些研究的结果将填补关于甲型病毒组装、成熟病毒与中和抗体相互作用、甲型病毒与宿主细胞脂膜相互作用机制的知识空白，并提供开发有效药物和疫苗所需的知识。

DESCRIPTION (provided by applicant): Alphaviruses can be serious, sometimes lethal, human pathogens that belong to the family Togaviridae. Only the alphaviruses and the rubiviruses are classified as Togaviruses. The alphavirus group is widely distributed across the globe, and various members of the alphavirus genus have been isolated on every continent except Antarctica. There are approximately 27 different alphaviruses that are capable of infecting various vertebrate species such as humans, horses and rodents. Based on their distribution and the symptoms they cause, the alphaviruses can be further classified as either Old World, which includes Europe, Asia, Australia and Africa or New World, which includes the Americas. Transmission of alphaviruses between individuals and species occurs mostly via mosquitoes, which makes alphaviruses members of the arthropod borne viruses. Disease can be manifested in one of two general forms, which depends on the type of virus. The Old World viruses (i.e. Chikungunya, Ross River and Sindbis viruses) present symptoms including fever, rash and arthralgia. The New World viruses (i.e. eastern, western and Venezuelan equine encephalitis viruses) present with fever, malaise, headache and encephalitis in up to 15% of infections, with a higher rate in children. Currently, there are no effective vaccines or drugs for individuals infected with an alphavirus. Therefore, a better understanding of alphavirus structure and function will aid in the development of safe and effective vaccines. The overall goal of this project is to determine structurally, the steps involved in the alphavirus lifecycle. Symptoms of infection include fever, rash, headache, and sometimes, encephalitis. Today, no effective vaccines exist for alphaviral infections. We will use Venezuelan equine encephalitis virus (VEEV) vaccine strain TC-83 to obtain atomic resolution structures of the virus with associated surface proteins by use of cryo-electron microscopy and x-ray crystallography. By use of neutralizing antibodies, we will trap the virus in intermediate stages of the viral lifecycle, follwed by structural analysis of the virus:antibody complex in order to delineate the complex conformational changes required for viral assembly, infection and maturation. The results of these studies will fill a gap in knowledge surrounding alphavirus assembly, the interaction of the mature virus with neutralizing antibodies, the mechanism by which alphaviruses interact with the lipid membrane of host cells, and provide the knowledge needed for the development of effective drugs and vaccines.