Chronic infection of the liver by hepatitis C virus (HCV) induces a range of host factors including IFN-stimulated genes such as ISG15. ISG15 functions as an antiviral factor that limits virus replication. Previous studies have suggested that ISG15 could influence HCV replication in both a positive and a negative manner. In this report, we determined the effect of ISG15 on HCV RNA replication in two independent cell lines that support viral genome synthesis by inhibiting ISG15 expression through small interfering RNA, short-hairpin RNA and CRISPR/Cas9 gene knockout approaches. Our results demonstrated that ISG15 impairs HCV RNA replication in both the presence and absence of IFN stimulation, consistent with an antiviral role for ISG15 during HCV infection. ISG15 conjugation to protein substrates typically requires the E3 ligase, HERC5. Our results showed that the inhibitory effect of ISG15 on HCV RNA replication does not require its conjugation to substrates by HERC5.
AbeH., HayesC.N., OchiH., TsugeM., MikiD., HiragaN., ImamuraM., TakahashiS., KuboM., other authors. 2011; Inverse association of IL28B genotype and liver mRNA expression of genes promoting or suppressing antiviral state. J Med Virol 83:1597–1607 [View Article][PubMed]
BensadounP., RodriguezC., SoulierA., HiggsM., ChevaliezS., PawlotskyJ.M.2011; Genetic background of hepatocyte cell lines: are in vitro hepatitis C virus research data reliable?. Hepatology 54:748 [View Article][PubMed]
BroeringR., ZhangX., KottililS., TripplerM., JiangM., LuM., GerkenG., SchlaakJ.F.2010; The interferon stimulated gene 15 functions as a proviral factor for the hepatitis C virus and as a regulator of the IFN response. Gut 59:1111–1119 [View Article][PubMed]
ChenL., SunJ., MengL., HeathcoteJ., EdwardsA.M., McGilvrayI.D.2010; ISG15, a ubiquitin-like interferon-stimulated gene, promotes hepatitis C virus production in vitro: implications for chronic infection and response to treatment. J Gen Virol 91:382–388 [View Article][PubMed]
EverettR.D., RechterS., PapiorP., TavalaiN., StammingerT., OrrA.2006; PML contributes to a cellular mechanism of repression of herpes simplex virus type 1 infection that is inactivated by ICP0. J Virol 80:7995–8005 [View Article][PubMed]
HoffmannT.W., DelfosseF., HelleF., FrançoisC., DuverlieG., CastelainS.2014; The expression of HCV-associated host factors is dependent on the hepatoma cell line used in HCV studies. Arch Virol 159:527–534 [View Article][PubMed]
JonesD.M., DominguesP., Targett-AdamsP., McLauchlanJ.2010; Comparison of U2OS and Huh-7 cells for identifying host factors that affect hepatitis C virus RNA replication. J Gen Virol 91:2238–2248 [View Article][PubMed]
KimM.J., YooJ.Y.2010; Inhibition of hepatitis C virus replication by IFN-mediated ISGylation of HCV-NS5A. J Immunol 185:4311–4318 [View Article][PubMed]
MitsuiK., NakanishiM., OhtsukaS., NorwoodT.H., OkabayashiK., MiyamotoC., TanakaK., YoshimuraA., OhtsuboM.1999; A novel human gene encoding HECT domain and RCC1-like repeats interacts with cyclins and is potentially regulated by the tumor suppressor proteins. Biochem Biophys Res Commun 266:115–122 [View Article][PubMed]
SuppiahV., MoldovanM., AhlenstielG., BergT., WeltmanM., AbateM.L., BassendineM., SpenglerU., DoreG.J., other authors. 2009; IL28B is associated with response to chronic hepatitis C interferon-α and ribavirin therapy. Nat Genet 41:1100–1104 [View Article][PubMed]
TanakaY., NishidaN., SugiyamaM., KurosakiM., MatsuuraK., SakamotoN., NakagawaM., KorenagaM., HinoK., other authors. 2009; Genome-wide association of IL28B with response to pegylated interferon-α and ribavirin therapy for chronic hepatitis C. Nat Genet 41:1105–1109 [View Article][PubMed]
Targett-AdamsP., McLauchlanJ.2005; Development and characterization of a transient-replication assay for the genotype 2a hepatitis C virus subgenomic replicon. J Gen Virol 86:3075–3080 [View Article][PubMed]
WernekeS.W., SchilteC., RohatgiA., MonteK.J., MichaultA., Arenzana-SeisdedosF., VanlandinghamD.L., HiggsS., FontanetA., other authors. 2011; ISG15 is critical in the control of Chikungunya virus infection independent of UbE1L mediated conjugation. PLoS Pathog 7:e1002322 [View Article][PubMed]