NF-κB is involved in the inhibition of IFN-α by FN.

(A) NC-KD cells were transfected with pNF-κB-Luc (5 ×NF-κB binding site promoter driven luciferase reporter plasmid). At 24 h post transfection, cells were mock infected or SeV (MOI = 1) infected along with the treatment of indicated concentration of BAY-11 (μM). Cells were harvested for luciferase assay at 48 h post transfection. (B) NC-KD or FN-KD cells were mock infected or Sev (MOI = 1) infected. At 24 h post infection, cell culture were replaced with medium containing DMSO or BAY-11 (1 μM) for another 24 h. IFN-α mRNA level was determined by qRT-PCR. (C) NC-KD and FN-KD cells were transfected with pNF-κB-Luc. At 24 h post transfection, cells were mock infected or SeV (MOI = 1) infected. Cells were harvested for luciferase assay at 48 h post transfection.(D) NC-KD and FN-KD cells were mock infected or SeV (MOI = 1) infected for 12 h. Cytoplasmic and nuclear fractions were prepared for western blot with indicated antibodies to determine the localization of NF-κB subunits. All experiments were repeated at least three times with similar results. Data represent means ± SD, n = 3 (*p<0.05).