Fig. 2.

Subcellular localization and function analysis of canine STING. (A) MDCK cells were co-transfected with C-terminal EGFP-tagged STING (STING-EGFP) and pDsRed2-ER. Cells were stained with DAPI 24 h post-transfection and analyzed using confocal microscopy. (B, C) MDCK Cells (B) and 293T cells (C) were co-transfected with 50–200 ng of the plasmid Flag-STING and IFN-Luc along with 0.01 μg of pRL-TK. (D–G) MDCK Cells (D, F, H) and 293T cells (E, G, I) were co-transfected with 0.25 μg of one of reporter plasmids-NF-κB-Luc (D, E), IRF3-Luc (F,G) or ISRE-Luc (H, I) along with 0.02 μg of pRL-TK and 0.25 μg of the Flag-STING or empty vector. SeV stimulation was used as a positive control. 24 h after transfection luciferase activity was measured. (J) MDCK cells were transfected with 0.25 μg of the indicated expression plasmid, Flag-STING, or empty vector. SeV infection was used as a positive control. 24 h post-transfection the mRNA levels of ISG15 and viperin were examined using qPCR. ISGs levels were normalized to the level of GAPDH. * represent differences between experimental and control groups (p < 0.05).