Structure and function of Hepatitis C Virus glycoproteins

丙型肝炎病毒感染全球约2亿人，是西方世界肝移植的主要原因。目前还没有疫苗，干扰素是唯一可用的治疗方法，在清除病毒感染方面只取得了有限的成功。丙型肝炎病毒与黄病毒有较远的亲缘关系，如森林脑炎病毒和黄热病病毒。所有病毒都通过受体附着在靶细胞上，从而启动感染过程。在丙型肝炎病毒中，包膜糖蛋白与靶细胞表面未知的受体相互作用，导致病毒内化到内吞体内。据认为，这些内小体的低pH环境触发了病毒和细胞膜的融合。融合后，病毒的基因组被释放到靶细胞中，并开始复制过程。启动这些过程的实际事件对丙型肝炎病毒尚不清楚，但据信是通过两种包膜糖蛋白介导的。在这个项目中，我们试图更好地了解病毒融合和进入的过程。我们有了关于两种包膜糖蛋白定位的新信息，这将使我们能够仔细检查病毒融合是如何发生的。使用生化方法，我们将研究它们的结构和功能，并研究这与广为人知的黄病毒融合和进入模式的关系。我们将通过发展体外丙型肝炎病毒融合试验来测试改变丙型肝炎病毒包膜糖蛋白结构的功能后果。丙型肝炎病毒融合的检测对于未来识别病毒受体、检测抗体在病毒中和中和的作用以及可用于测试病毒融合和进入的新型抑制剂是必不可少的。

Hepatitis C Virus infects approximately 200 million people world-wide and is the major cause of liver transplantation in the Western world. At present there is no vaccine and interferon alpha is the only therapy available and has only limited success in clearing viral infection. HCV is distantly related to flaviviruses eg tick-borne encephaltitis virus and yellow fever virus. All viruses attach to target cells using receptors to initiate the infection process. In the case of HCV, the envelope glycoproteins interact with as yet unknown receptors on the target cell surface resulting in the virus being internalized into endosomes. It is believed that the low pH environment of these endosomes triggers fusion of the viral and cellular membranes. After fusion the genome of the virus is released into target cells and begins the replication process. The actual events intitiating these processes are not understood for HCV but are believed to be mediated using two envelope glycoproteins. In this project we seek to gain a greater understanding of how viral fusion and entry occurs. We have new information regarding the localisation of the two envelope glycoproteins that will now enable us to carefully examine how viral fusion occurs. Using biochemical approaches, we will study their structure and function and examine how this relates to the well understood flavivirus mode of fusion and entry. We will test the functional consequences of altering the structure of the HCV envelope glycoproteins by developing in vitro assays of HCV fusion. Assays for HCV fusion are essential for future studies to identify viral receptors, examine the role of antibody in viral neutralization and can be used to test novel inhibitors of viral fusion and entry.