title: Cytosolic phospholipase A2 gamma is involved in hepatitis C virus replication and assembly.
abstract: Similar to other positive-sense, single-stranded RNA viruses, hepatitis C virus (HCV) replicates its genome in a remodeled intracellular membranous structure known as the membranous web (MW). To date, the process of MW formation remains unclear. It is generally acknowledged that HCV nonstructural protein 4B (NS4B) can induce MW formation through interaction with the cytosolic endoplasmic reticulum (ER) membrane. Many host proteins, such as phosphatidylinositol 4-kinase IIIα (PI4KIIIα), have been identified as critical factors required for this process. We now report a new factor, the cytosolic phospholipase A2 gamma (PLA2G4C), which contributes to MW formation, HCV replication, and assembly. The PLA2G4C gene was identified as a host gene with upregulated expression upon HCV infection. Knockdown of PLA2G4C in HCV-infected cells or HCV replicon-containing cells by small interfering RNA (siRNA) significantly suppressed HCV replication and assembly. In addition, the chemical inhibitor methyl arachidonyl fluorophosphonate (MAFP), which specifically inhibits PLA2, reduced HCV replication and assembly. Electron microscopy demonstrated that MW structure formation was defective after PLA2G4C knockdown in HCV replicon-containing cells. Further analysis by immunostaining and immunoprecipitation assays indicated that PLA2G4C colocalized with the HCV proteins NS4B and NS5A in cells infected with JFH-1 and interacted with NS4B. In addition, PLA2G4C was able to transport the HCV nonstructural proteins from replication sites to lipid droplets, the site for HCV assembly. These data suggest that PLA2G4C plays an important role in the HCV life cycle and might represent a potential target for anti-HCV therapy.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, People's Republic of China.
authors.forename: Song
authors.initials: S
authors.lastname: Xu
authors.forename: Rongjuan
authors.initials: R
authors.lastname: Pei
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Han
authors.forename: Juan
authors.initials: J
authors.lastname: Lai
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Chunchen
authors.initials: C
authors.lastname: Wu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Mengji
authors.initials: M
authors.lastname: Lu
authors.forename: Xinwen
authors.initials: X
authors.lastname: Chen
mesh_terms: D016718:Arachidonic Acid / Q000494:pharmacology; D001095:Arachidonic Acids / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism; D055785:Gene Knockdown Techniques; D054513:Group IV Phospholipases A2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016174:Hepacivirus / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D063065:Organophosphonates / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017361:Viral Nonstructural Proteins / Q000378:metabolism; D019065:Virus Assembly / Q000187:drug effects / Q000502:physiology*; D014779:Virus Replication / Q000187:drug effects / Q000502:physiology*
chemical_list: D001095:Arachidonic Acids; D017931:DNA Primers; C080107:NS4B protein, flavivirus; D063065:Organophosphonates; D034741:RNA, Small Interfering; D017361:Viral Nonstructural Proteins; C104810:methyl arachidonylfluorophosphonate; D016718:Arachidonic Acid; D054513:Group IV Phospholipases A2