title: Functional Analysis of Hepatitis C Virus (HCV) Envelope Protein E1 Using atrans-Complementation System Reveals a Dual Role of a Putative Fusion Peptide of E1 in both HCV Entry and Morphogenesis.
abstract: Hepatitis C virus (HCV) is an enveloped RNA virus belonging to theFlaviviridaefamily. It infects mainly human hepatocytes and causes chronic liver diseases, including cirrhosis and cancer. HCV encodes two envelope proteins, E1 and E2, that form a heterodimer and mediate virus entry. While E2 has been extensively studied, less has been done so for E1, and its role in the HCV life cycle still needs to be elucidated. Here we developed a new cell culture model for HCV infection based on thetrans-complementation of E1. Virus production of the HCV genome lacking the E1-encoding sequence can be efficiently rescued by the ectopic expression of E1 intransThe resulting virus, designated HCVΔE1, can propagate in packaging cells expressing E1 but results in only single-cycle infection in naive cells. By using the HCVΔE1 system, we explored the role of a putative fusion peptide (FP) of E1 in HCV infection. Interestingly, we found that the FP not only contributes to HCV entry, as previously reported, but also may be involved in virus morphogenesis. Finally, we identified amino acid residues in FP that are critical for biological functions of E1. In summary, our work not only provides a new cell culture model for studying HCV but also provides some insights into understanding the role of E1 in the HCV life cycle.IMPORTANCEHepatitis C virus (HCV), an enveloped RNA virus, encodes two envelope proteins, E1 and E2, that form a heterodimeric complex to mediate virus entry. Compared to E2, the biological functions of E1 in the virus life cycle are not adequately investigated. Here we developed a new cell culture model for single-cycle HCV infection based on thetrans-complementation of E1. The HCV genome lacking the E1-encoding sequence can be efficiently rescued for virus production by the ectopic expression of E1 intransThis new model renders a unique system to dissect functional domains and motifs in E1. Using this system, we found that a putative fusion peptide in E1 is a multifunctional structural element contributing to both HCV entry and morphogenesis. Our work has provided a new cell culture model to study HCV and provides insights into understanding the biological roles of E1 in the HCV life cycle.
authors.affiliation: CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Chi
authors.affiliation: Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China jzhong@sibs.ac.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhong
mesh_terms: D045744:Cell Line, Tumor; D018920:Coculture Techniques; D057809:HEK293 Cells; D016174:Hepacivirus / Q000502:physiology*; D006801:Humans; D008561:Membrane Fusion; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D014759:Viral Envelope Proteins / Q000502:physiology*; D053586:Virus Internalization; D014779:Virus Replication
chemical_list: C087035:E1 protein, Hepatitis C virus; D014759:Viral Envelope Proteins
keywords: E1; envelope proteins; fusion peptide; hepatitis C virus; trans-complementation; virus entry; virus morphogenesis