FIGURE 3.

Screening of HCMV cDNA libraries to identify genes that down-regulate STING-induced IFN-β promoter activation. HEK293T cells were co-transfected with the vector expressing STING, IFN-β promoter-driven firefly luciferase reporter and control renilla luciferase reporter plasmids plus either pDEST-12.2 or pDEST-12.2 expressing cDNAs encoding 133 HCMV-Towne ORFs. After 24 h, 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 HCMV-Towne ORFs on STING-induced IFN-β promoter activation, RLU in cells co-transfected with the vector expressing STING and pDEST-12.2 vector expressing HCMV-Towne ORF was divided by that in cells co-transfected with control vector and pDEST-12.2 vector expressing HCMV-Towne ORF. To analyze the relative luciferase activity, STING-induced luciferase activities without HCMV-Towne ORF were set to 100%. Luciferase data shown here represent three independent experiments ±SD.