FIG 1.

RIOK3 is required for IFN-β induction by BDNA. (A) Effect of RIOK3 RNAi on BDNA-induced ISRE promoter activation. HEK293T_ISRE cells were transfected with the indicated siRNAs and were left untreated or transfected with BDNA. The fold activation was calculated compared to the untreated cells. (B) Effect of RIOK3 RNAi on RIOK3 expression. HEK293T cells were transfected with the indicated siRNAs. Lysates were analyzed by immunoblotting using the indicated antibodies. (C and D) Effect of RIOK3 RNAi on BDNA-induced IFN-β promoter activation and IFN-α-induced ISRE promoter activation. HEK293T cells were cotransfected with the indicated siRNAs, PGK_Renilla-luciferase reporter and either IFN-β_luc (C) or ISRE_luc (D). Cells were left untreated or transfected with BDNA (C) or treated with 3 × 10⁴ U of IFN-α/ml (D) for 20 h before luciferase assays were performed. The fold activation was calculated compared to the untreated cells. (E and F) Effect of RIOK3 RNAi on BDNA-induced ifnb1 and isg15 transcription and IFN-β expression. The relative ifnb1 and isg15 mRNA level was measured by quantitative PCR (QPCR) (E), and the concentration of IFN-β in the supernatant was measured by ELISA (F). (G) Effect of RIOK3 RNAi on BDNA-induced ifnb1 expression in THP-1 cells and murine BMMs. The relative ifnb1 mRNA level was measured by QPCR. *, P < 0.05 (Student t test). Error bars indicate the SD. All results are representative of three replicate experiments.