Fig. 4.

An overlapping IRF3/7/9 consensus cluster (IRF cluster; IRFC) is required for type-I interferon (IFN)-dependent promoter activity. NIH3T3 cells were transfected with luciferase reporter vectors and then treated with 10³ U/mL IFN-α₄ for 24 h the next day. Promoter activity was assayed by dual luciferase reporter assay relative to Renilla luciferase and normalized to the pGL3 empty vector. Significance was determined by a 1-tailed (¹p) or 2-tailed (²p) t test on log-transformed values (n = 3 experiments). * p < 0.05.