Fig. 1

Flavivirus TBEV viral proteins antagonize IFN-I production. A HEK293T cells were transfected with plasmids expressing GFP or TBEV proteins and RIG-I-N together with IFNβ-Luc and control plasmids, the luciferase activity was measured at 20 h post-transfection (hpt). The suppression of the activated IFNβ promoter of TBEV proteins was compared with GFP group. B and C TBEV prM or EV plasmids, poly(I:C) along with IFNβ-Luc (B) or ISRE-Luc (C) were transfected into HEK293T cells, the luciferase activity was measured at 20 (B) or 24 hpt (C). D TBEV prM or EV plasmids, RIG-I-N along with NF-κB-Luc were transfected into HEK293T cells, the luciferase activity was measured at 24 hpt. E Empty vector (EV) or TBEV prM plasmid along with poly(I:C) were transfected into HEK293T cells, the expression of IFNB1, ISG56 and CXCL10 were analyzed by qPCR, GAPDH was used as normalizer. F TBEV prM plasmid and poly (I:C) were transfected into HEK293T cells, the cells were harvested at 24 hpt for immunoblot analysis by the indicating antibodies. The relative intensity of phosphorylated IRF3 and TBK1 was calculated using ImageJ software. G The Myc-IRF3 and EGFP-IRF3 together with TBEV prM or EV plasmids were co-transfected into HepG2 cells, cells were harvested at 30 hpt, and the cell lysates and immunoprecipitants were analyzed by immunoblot using the indicated antibodies. H Myc-IRF3 together with TBEV prM or EV plasmids were co-transfected into HEK293T cells. After 24 h, the cells were activated with poly (I:C) for 8 h. The separated nuclear and cytoplasmic proteins were analyzed for IRF3 by immunoblot. I EGFP-IRF3 and TBEV prM plasmids were co-transfected into HeLa cells. After 24 h, the cells were activated with poly (I:C) for 8 h and stained with indicated antibodies. Green, IRF3 signal; Red, TBEV prM signal; Blue, DAPI (the nuclear signal). Bar, 10 μm. Bars represent the mean of three biological replicates and all data are expressed as mean ± SE. *p < 0.05, **p < 0.01