FN promotes HBV expression by activating HBV EI and EII activities.

(A) Huh7 cells were transfected with HBV EI or EII along with pFN and then cell culture medium was refreshed with serum-free medium 6 h post-transfection. Luciferase activity was measured 24 h after serum starvation. Huh7 cells were transfected with wild-type EI or mutant EI HNF-4α-Mut (B), wild-type EII or mutant EII HNF-4α-Mut (C) along with shFN or shNC, and then cell culture medium was refreshed with serum-free medium 6 h post-transfection. Luciferase activity was measured 24 h after serum starvation. (D) Huh7 cells were transfected with shFN or shNC. Cells were lysed 48 h post-transfection and HNF-4α levels were determined by qRT-PCR (upper panel) and western blot (lower panel). (E) Huh7 cells were transfected with shFN or shNC along with pHBV and then ChIP analysis was performed to assess HNF-4α binding capability to HBV enhancers 48 h post-transfection. All experiments were repeated at least three times with similar results. Data represent means ± SD, n = 3 (*p<0.05).