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. 2019 Jul 24;133(5):jcs230409. doi: 10.1242/jcs.230409

Fig. 1.

Fig. 1.

The overexpression of DDX56 markedly inhibits the virus-triggered IFN-β signaling pathway. (A–D) DDX56 inhibited the SeV- or poly(I:C)-induced activations of the ISRE and the IFN-β promoter in 293T cells. 293T cells (105) were transfected with the ISRE or IFN-β promoter luciferase plasmids (0.1 μg) and the DDX56 expression plasmid (100 ng). At 20 h after transfection, the cells were infected with or without SeV for 10 h or were treated with poly(I:C) (1 µg/ml) or left untreated for 18 h before the luciferase assays were performed. Shown are representative experiments of three independent experiments with mean±s.d. of three technical replicates. **P<0.01. (E) Overexpression of DDX56 inhibits the SeV-induced phosphorylation of TBK1, IRF3 and IκBα. The stably transfected DDX56 293T cells were infected with SeV for the indicated times. Cell lysates were analyzed by immunoblotting (WB) with the indicated antibodies. The degree of protein phosphorylation was calculated by ImageJ software and is presented under the blot. (F–I) DDX56 inhibited the SeV- and poly(I:C)-induced activations of ISRE and the IFN-β promoter in a dose-dependent manner in 293T cells. 293T cells (105) were transfected with the ISRE or IFN-β promoter luciferase plasmids (0.1 μg) and the indicated amount of DDX56 expression plasmid. At 24 h after transfection, the cells were infected with or without SeV for 10 h or were treated with poly(I:C) (1 µg/ml) or left untreated for 18 h before the luciferase assays were performed. Shown are representative experiments of three independent experiments with the mean±s.d. of three technical replicates. (J–N) Effects of DDX56 overexpression on SeV-triggered transcription of IFNB1, TNFa, Il8, Rantes and Isg56 genes. The DDX56-overexpressing stable 293T cells (4×105) were left uninfected or infected with SeV for 12 h before qRT-PCR was performed. Shown are representative experiments of three independent experiments with the mean±s.d. of three technical replicates. *P<0.05, **P<0.01. EV, empty vector; Luc, luciferase; F, Flag tag.