Fig. 4.

The effect of PDCoV infection on IFN-λ1 induced by molecules in the RIG-I signaling pathway. IPI-2I cells were transfected with a plasmid expressing RIG-I (A), MDA5 (B), MAVS (C), TBK1 (D), IRF1 (E) or an empty vector, along with p-55λ1-(-225/-36)-Luc and pRL-TK, then the cells were mock-infected or infected with PDCoV at a MOI of 0.5 for 24 h. Cell lysates were prepared for dual-luciferase reporter assays. All data are presented as the means ± SD of three independent experiments (*p < 0.05). The expressions of Flag-tagged RIG-I, MDA5, MAVS, TBK1 or IRF1 were confirmed by western bot with anti-Flag antibody. Antibodies against N protein was used to confirm the infection of PDCoV. β-actin was detected by western blot and used as a control for sample loading.