FIG. 4.

(A) VeroE6 cells were left uninfected or were infected for 1 h with WT SARS-CoV (MOI, ∼5) and further incubated for 8 h. IFN-α (2,000 U/ml) was then added for 2, 4.5, and 7 h before immunoblot analysis. (B) 293T cells transfected with 9-27 ISREx4CAT and empty vector (−) or Flag-nsp constructs were left untreated (Co) or treated with 500 U/ml of IFN-α for 18 h, and reporter activity was determined. (C) 293T cells transfected with ISG15 ISREx3CAT and empty vector (Vec.) or vector for nsp1 were left untreated (Co), infected with SeV, or treated with 500 U/ml of IFN-α or IFN-γ for 18 h, and reporter activity was determined.