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，对丙型肝炎病毒复制的研究一直受到阻碍。在功能和结构研究中，研究者们一直专注于丙型肝炎病毒基因的表达。到目前为止，大多数丙型肝炎病毒非结构蛋白都定位于内质网(ER)。因此，假设丙型肝炎病毒NS4A/B前体蛋白的表达导致内质网样室的肿胀，并抑制内质网和高尔基体之间的蛋白运输。因此，丙型肝炎病毒/NS4A/Bo=前体蛋白可能抑制细胞分泌途径，改变细胞内的隔室，形成病毒RNA复制复合体。在这项提案中，将研究肿胀的细胞内间隔的性质及其与丙型肝炎病毒NS4A/B前体蛋白的关系。还将检测其他丙型肝炎病毒非结构蛋白(NS2/3/4A、NS4B/5A、NS4B/5A、NS4A和NS5B)抑制蛋白质运输的能力。利用MHC I类分子，将测试这种由丙型肝炎病毒蛋白抑制的特异性。类似的研究将对BVDV的同源蛋白进行，BVDV是一种可以在组织培养中方便和安全地生长的黄病毒。从这些研究中获得的信息将有助于抑制剂的选择或发病机制。

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.