HCV Nonstructural Proteins and Host Protein Secretion

丙型肝炎病毒（HCV）是世界范围内导致肝癌的主要原因之一。由于缺乏方便的动物模型或可靠的组织培养系统来传播病毒，HCV复制的研究一直受到阻碍。研究人员将重点放在HCV基因的功能和结构研究上，迄今为止检测的大多数HCV非结构蛋白都定位于内质网（ER）。因此，我们假设HCV NS4A/B前体蛋白的表达导致内质网样隔室肿胀，抑制内质网和高尔基体之间的蛋白质运输。因此，HCV/NS4A/B o=前体蛋白可能抑制细胞分泌途径并修饰细胞内区室形成病毒RNA复制复合物。在本研究中，将研究细胞内腔室肿胀的性质及其与HCV NS4A/B前体蛋白的关系。其他HCV非结构蛋白（NS2/3/4A、NS4B/5A、NS4B/5A、NS4A和NS5B）抑制蛋白转运的能力也将被检测。使用MHC I类分子，将测试HCV蛋白对这种抑制的特异性。BVDV是一种可以方便、安全地在组织培养中培养的黄病毒，将对其同源蛋白进行类似的研究。从这些研究中获得的信息将有助于选择抑制剂或发病机制。

Hepatitis C virus (HCV) is one of the leading causes of liver cancer worldwide. Studies on HCV replication have been hampered by the lack of a convenient animal model or a reliable tissue culture system to propagate the virus. Investigators have focused on expression of HCV genes for functional and structural studies Most of the HCV non- structural proteins examined so far have been localized to the endoplasmic reticulum (ER). It is assumed therefore that expression of HCV NS4A/B precursor proteins results in the swelling of ER-like compartments and inhibits protein traffic between ER and Golgi apparatus. Thus, it is likely that HCV/NS4A/B o=precursor proteins inhibit cellular secretory pathway and modify intracellular compartments to form viral RNA replication complexes. In this proposal, the nature of the swollen intracellular compartments and their relationship to the HCV NS4A/B precursor proteins will be investigated. The ability of other HCV non-structural proteins (NS2/3/4A, NS4B/5A, NS4B/5A, NS4A and NS5B) to inhibit protein traffic will also be examined. Using MHC class I molecules, the specificity of this inhibition by HCV proteins will be tested. Similar studies will be done with homologous proteins of BVDV, a flavivirus that can be conveniently and safely be grown in tissue culture. Information gained from these studies will be useful in the selection of inhibitors or pathogenesis.