Fig 4. IFN-λ decreases miR-122 transcription in HCV cells.

(A) Up regulated microRNAs expression in R4-GFP cells after IFN-λ treatment. (B) Down regulated MicroRNAs expression in R4-GFP cells after IFN-λ treatment. (C) Northern blot for miR-122 in R4-GFP cells treated with either IFN-α or IFN-λ for 6 hours. (D and E) S3-GFP, R4-GFP and persistently HCV infected Huh 7.5 cells were treated with either IFN-α (1000 IU/mL) or IFN-λ1 (100 ng/mL) for six hours. One microgram of total RNA was used for the measurement of miR-122 by real-time RT-PCR. (F and G) R4-GFP cells were transfected with increasing concentrations (25–100 pmole) of miR-122 mimic for 24 hours and then treated with IFN-λ for 48 hours. The effect of the mimic on the antiviral action of IFN-λ was assessed by fluorescence microscopy and then GFP positive cells were quantified by flow cytometry. (H and I) MiR-122-Luc promoter construct was transfected into S3-GFP and R4-GFP cells and following the transfection step, cells were treated with either IFN-α (1000 IU/mL) or IFN-λ (100ng/mL) for 6 hours. The effect of the treatment on the promoter activity was measured by comparing the fold change of firefly luciferase in the treated cells over the untreated control, *p≤0.05, **p≤0.001.