@article{mbs:/content/journal/jgv/10.1099/jgv.0.000607, author = "Du, Xiaoting and Pan, Tingting and Xu, Jun and Zhang, Yang and Song, Wuhui and Yi, Zhigang and Yuan, Zhenghong", title = "Hepatitis C virus replicative double-stranded RNA is a potent interferon inducer that triggers interferon production through MDA5", journal= "Journal of General Virology", year = "2016", volume = "97", number = "11", pages = "2868-2882", doi = "https://doi.org/10.1099/jgv.0.000607", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000607", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", keywords = "HCV", keywords = "MDA5", keywords = "replication complex", keywords = "RIG-I", keywords = "innate immunity", keywords = "interferon", 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.", }