Functions of NS3 in HCV RNA Replication

描述（由申请人提供）：慢性丙型肝炎病毒（HCV）感染是严重肝病（包括肝硬化和肝细胞癌）的常见原因。世界上大约2%的人口感染了这种病毒，使其成为一个重大的健康威胁。在美国，用干扰素-α和利巴韦林的组合治疗（目前唯一许可的用于该疾病的疗法）从少于50%的感染最流行的HCV基因型（基因型1）的患者中消除病毒。HCV NS 3编码RNA复制所需的几种重要酶活性，包括蛋白酶、解旋酶和NTR。NS 3作为蛋白酶对于病毒复制是必需的，因为它蛋白水解地加工病毒多聚蛋白，这是病毒复制酶复合物组装所需的，因此是抗HCV感染的抗病毒药物开发工作中的重要靶标。该项目的目标是了解NS 3蛋白在培养的Huh 7细胞中HCV RNA复制中的分子作用机制，通过检查HCV复制子突变体，这些突变体在瞬时复制水平上显示出显着差异，NS 3蛋白酶结构域内有一些氨基酸变化。该项目的目标是：具体目标1：确定NS 3中的复制增强突变是否改变HCV非结构蛋白加工，并确定改变的非结构蛋白加工是否导致差异RNA复制;具体目标2：确定NS 3是否通过与NS 5A相互作用调节RNA复制。这项应用的结果将增强有关病毒RNA复制的基本分子生物学知识，改善目前可用的系统来研究HCV，并有助于未来的药物开发工作，从而增强对这种危险病原体的治疗。

DESCRIPTION (provided by applicant): Chronic hepatitis C virus (HCV) infection is a common cause of serious liver diseases, including cirrhosis and hepatocellular carcinoma. Approximately 2% of the world's population is infected with this virus, rendering it a major health threat. In the U.S., treatment with a combination of interferon-alpha and ribavirin, the only currently licensed therapies for this disease, eliminates the virus from less than 50% of those infected with the most prevalent HCV genotype, genotype 1. HCV NS3 encodes several important enzyme activities required for RNA replication, including protease, helicase and NTPase. NS3 as the protease is essential for viral replication as it proteolytically processes viral polyprotein, which is required for viral replicase complex assembly, and thus an important target in antiviral drug development efforts against HCV infection. The goal of this project is to understand the molecular mechanism of action of NS3 protein in HCV RNA replication in cultured Huh7 cells, by examining HCV replicon mutants, which have shown significant differences in transient replication levels, with a few amino acid changes within the protease domain of the NS3. The aims of this project are: Specific aim1: To determine if replication-enhancing mutations in NS3 alter HCV nonstructural protein processing and to determine whether altered nonstructural protein processing results in differential RNA replication; Specific aim 2: To determine if NS3 modulates RNA replication through interaction with NS5A. The outcome of this application will enhance basic molecular biological knowledge concerning viral RNA replication, improve the currently available system to study HCV, and help future drug development efforts leading to enhanced therapy against this dangerous pathogen.