Fig 1.

US11 inhibits SeV-mediated activation of the IFN-β and NF-κB promoter activities. (A, C, and D) HEK 293T cells were transfected with 500 ng of IFN-β promoter reporter plasmid p125-luc (A), NF-κB-Luc (C), or (pRDIII-I)4-Luc (D), together with Renilla luciferase plasmid pRL-TK (50 ng) and pCMV-HA empty vector or plasmids encoding the indicated viral proteins (1,000 ng). At 24 h after transfection, cells were left untreated or infected with 100 HAU ml⁻¹ SeV as indicated, and luciferase activity was measured 16 h postinfection. (B) As in panel A, except an increased amount of US11-HA expression plasmid, as indicated, was used. The expression of US11 was analyzed by Western blotting using anti-HA and anti-β-actin (as a control) monoclonal antibodies. Data are expressed as relative luciferase activities with standard deviations for three independent experiments performed in duplicate. (E) HEK293T cells were transfected with pCMV-HA empty vector or US11-HA expression plasmid. At 24 h posttransfection, cells were mock infected or infected with 100 HAU ml⁻¹ SeV for 16 h before RT-PCR was performed using GAPDH and IFN-β primers. (F) Medium from infected cells in panel E was isolated and analyzed by ELISA for IFN-β secretion as described in Materials and Methods. The data represent means + standard deviations for three replicates.