C19orf66 is an interferon-induced inhibitor of HCV replication restricting formation of the viral replication organelle

Hepatitis C virus (HCV) infection constitutes a global health problem with 71 million people currently chronically infected. Recent studies have reported that C19orf66 is expressed as an interferon (IFN)-stimulated gene; however, the intrinsic regulation of this gene within the liver as well as its antiviral effects against HCV remains elusive. In this study, we observed an upregulation of C19orf66 in vivo and ex vivo in response to HCV infection and to IFN therapy. Expression of C19orf66 restricted HCV infection, whereas CRIPSPR/Cas9 mediated knockout of C19orf66 attenuated IFN-mediated suppression of HCV replication. Co-immunoprecipitation followed by mass spectrometry identified a stress granule dominated interactome of C19orf66. Mechanistic studies revealed that C19orf66 expression impairs HCV-induced elevation of PI(4)P and alters the morphology of the viral replication organelle, designated membranous web, thus suppressing viral RNA replication. Collectively, our data suggest that C19orf66 contributes to the innate immune response against HCV in the liver. Huh-7.5 cells stably expressing empty vector or 3xFLAG-C19orf66 were subjected to RNA-seq.