FIG. 1.

vIRF-1 inhibited synergistic activation of IFNA4 promoter by NDV and IRF-1 or IRF-3. The IFNA4 CAT reporter plasmid (1 μg) was cotransfected into NIH 3T3 cells with 1 μg of either pcDNA vector (Con), IRF-1, or IRF-3 expression plasmids, together with increasing amount of vIRF-1 expression plasmid (1 and 4 μg). Cells were infected with NDV 24 h after transfection for 16 h and analyzed for CAT activity. Error bars show standard errors for triplicate experiments.