FIG 1.

UL24 inhibits the activation of the IFN-β and IL-6 promoter induced by cGAS-STING and ISD-mediated production of IFN-β and IL-6. (A and B) HEK293T cells were cotransfected with an IFN-β–Luc (A) or IL-6–Luc (B) reporter plasmid, the pRL-TK control plasmid along with an empty vector, and plasmids encoding cGAS (15 ng) and STING (2.5 ng) with UL24. Luciferase activity was measured at 24 h posttransfection, and fold activation was determined compared to the empty vector. The expression of cGAS, STING, and UL24 was analyzed by WB using anti-Flag, anti-HA, and anti-Myc monoclonal antibodies. (C and D) HFF cells were infected with WT HSV-1 and the HSV-1 UL24X mutant at an MOI of 2 for 2 h and transfected with ISD (4 μg/ml) for another 10 h. Cells were harvested and subjected to RT-PCR to detect IFN-β (C) or IL-6 (D) mRNA. (E and F) HFF cells were infected with WT HSV-1 or the HSV-1 UL24X mutant and then transfected with ISD for another 16 h. Supernatants were subjected to an ELISA to detect IFN-β (E) or IL-6 (F). The data represent results from one of three independent experiments. Error bars represent standard deviations of data from three independent experiments. Statistical analysis was performed by using Student's t test (*, P < 0.05; **, P < 0.01; ***, P < 0.001; ns indicates that the comparison is not significant).