FIG. 1.

VRP infection decreases ISG expression independently of the viral structural proteins. Vero-81 cells were infected with VRP, which express GFP in place of viral structural proteins from the subgenomic 26S promoter (genome organization shown in panel A), at an MOI of 10 IU/cell for 4 h and then stimulated with 1,000 U of IFN-γ (B) or IFN-β (C)/ml. Total RNA was isolated after 3 or 6 h of IFN treatment, and the relative guanylate binding protein 2 (GBP2) (B) or TRIM-21 (C) mRNA expression was determined by real-time PCR analysis of cDNA. Individual samples were normalized to GAPDH. The average of each group was calculated and is represented relative to mock-infected, untreated samples. Error bars indicate one standard deviation. To determine significance, an analysis of variance was performed. Post hoc comparisons of relevant groups at each time point are indicated by brackets, along with associated P values.