FIGURE 9.

The effect of IE86 mutants on STING. (A) A schematic diagram of IE86 deletion mutants. TAD, transactivation domain; Zn, zinc finger domain; HLH, helix-loop-helix motif; NLS, nuclear localization sequence (B) HEK293T cells were co-transfected with the vector expressing STING, control renilla luciferase reporter and IFN-β promoter-driven firefly luciferase reporter plasmids plus pCS3-MT vector expressing 6X-myc-tagged IE86 WT or deletion mutants. At 48 h, IFN-β promoter-driven luciferase activity was measured using a dual luciferase assay system. IFN-β promoter-driven luciferase activity was expressed in RLU by normalizing firefly luciferase activity with constitutive renilla luciferase activity. To determine the effect of IE86 WT or deletion mutants on STING-induced IFN-β promoter activation, RLU in cells co-transfected with vectors expressing STING and IE86 WT or deletion mutants was divided by that in cells co-transfected with control vector and the vector expressing IE86 WT or deletion mutants. To analyze the relative luciferase activity, STING-induced luciferase activities without the vector expressing IE86 WT or deletion mutants were set to 100%. Luciferase data shown here represent three independent experiments ±SD. The asterisk (^∗) denotes a significant difference between control and IE86 (WT or deletion mutants) expressing samples, which was determined by the P-value of a two-sample t-test (P < 0.05). (C) HEK293T cells were co-transfected with vectors expressing STING and 6X-myc-tagged IE2 WT or deletion mutants. At 48 h after transfection, equal amounts of cell extracts were subjected to western blot analysis with antibodies to STING, c-Myc and tubulin.