EAV nsp1 inhibits the IRF-3 signaling pathway. Suppression of (a) RIG-I, (b) MDA-5, (c) MAVS, (d) TRIF, (e) IKKε, and (f) IRF-3-induced IRF-3 dependent reporter gene expression by EAV nsp1 in HEK293T cells. (a)–(f) Cells cultured in 24-well plates were cotransfected with plasmid pEFneo-RIG-I, pEFneo-MDA-5, pEGFP-N1-MAVS, pcDNA3-TRIF, pEFneo-IKKε, or pCAGGS-IRF-3 along with a pCAGGS expressing nsp1 protein or pCAGGS empty vector, pRL-SV40, and a luciferase reporter plasmid p55-CIB-Luc for 24 h. Cells were harvested and measured for firefly and Renilla luciferase activities. Relative luciferase (RLU) activity is defined as a ratio of firefly luciferase reporter activity to Renilla luciferase activity. Mean value ± SEM from three experiments is shown.