title: Hepatitis C virus replicative double-stranded RNA is a potent interferon inducer that triggers interferon production through MDA5.
abstract: The cytoplasmic RNA sensors, retinoic acid-inducible gene I and melanoma differentiation-associated gene 5, play crucial roles in innate sensing of hepatitis C virus (HCV). However, the exact identity of the IFN inducer generated during HCV infection is poorly understood. To identify the IFN inducer, we extracted the RNAs from HCV-replicating cells and introduced these into IFN signalling-competent cells to examine IFN production. RNAs isolated from HCV-replicating cells triggered robust IFN-β and IFN-λ production in Huh7 cells in a viral replication-dependent manner, preferentially through the melanoma differentiation-associated gene 5 but not through the retinoic acid-inducible gene I-mediated pathway. The IFN-inducing capacity of HCV RNA survived after calf intestinal alkaline phosphatase and ssRNA-specific S1 nuclease treatment, but was completely eliminated by dsRNA-specific RNase III digestion, suggesting that viral replicative dsRNA is an IFN inducer. Furthermore, HCV viral RNA extracted from replicating cells was sensitive to 5'-monophosphate-dependent 5'→3' exonuclease (TER) digestion, suggesting that the HCV genome lacks a 5'-triphosphate or -diphosphate. In semi-permeabilized cells, the HCV IFN inducer primarily resided in an enclosed membranous structure that protects the IFN inducer from RNase digestion. Taken together, we identified HCV replicative dsRNA as a viral IFN inducer enclosed within the viral replication factory.
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Du
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Pan
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Wuhui
authors.initials: W
authors.lastname: Song
authors.affiliation: Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yi
authors.affiliation: Institute of Biomedical Sciences, Fudan University, Shanghai, PR China.|Key Laboratory of Medical Molecular Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, PR China.|Institute of Medical Microbiology, Fudan University, Shanghai, PR China.
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D002460:Cell Line; D004261:DNA Replication; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism; D016174:Hepacivirus / Q000235:genetics* / Q000502:physiology; D006526:Hepatitis C / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D006801:Humans; D000072640:Interferon-Induced Helicase, IFIH1 / Q000235:genetics / Q000378:metabolism*; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism*; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000235:genetics* / Q000378:metabolism; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D012330:RNA, Double-Stranded; D016899:Interferon-beta; D007371:Interferon-gamma; C452815:IFIH1 protein, human; D000072640:Interferon-Induced Helicase, IFIH1