Role of RIG-I in the modulation of IFNβ1 by HCV -2/+1 frame mutants.

(A) Huh7 and Huh7.5 cells were transfected with JFH1wt, JFH1Δ, and JFH1Δ4 RNAs or mock-transfected and analyzed for IFNβ1 mRNA and HCV RNA by qRT-PCR after 72 hrs. (B) Huh7 cells were transfected with siRNAs and then transfected with JFH1wt and JFH1Δ4 RNAs or mock-transfected 48–72 hrs later. Cells were then analyzed for IFNβ1 and RIG-I mRNAs by qRT-PCR. Data were normalized by GAPDH mRNA. (C) Huh7 cells supporting JFH1wt, JFH1Δ, and JFH1Δ4 were incubated with 0, 100, or 250 U/ml of exogenous IFNα (NIAID Reference Reagent Repository and Sigma Aldrich) with change of cell culture medium daily for 72 hrs. Then, samples were collected and analyzed by qRT-PCR. Data are shown as percentage of respective 0 U/ml IFNα controls. Star indicates statistically significant difference (P < 0.05) compared to controls. Lines with P values also indicate statistically significant difference between those samples.