FIG 1.

IRAV is an interferon-stimulated gene. (A) qRT-PCR analysis of RNA expression in A549 cells after DENV infection at 0, 8, 16, 24, 48, and 72 h postinfection. Cells were infected with DENV at an MOI of 0.1 for 1 h, and samples were collected at time zero and the indicated time points. The samples were analyzed by qRT-PCR for DENV RNA (i), as well as for expression of IFN-β (ii), IRAV (iii), and the ISG IFIT3 (iv). The samples were normalized to the HPRT housekeeping gene, and the change in expression was calculated relative to time zero. The error bars represent standard deviations. *, P < 0.05. (B) Western blot analysis of IRAV expression in control A549 cells or IRF9 KO cells after DENV infection (72 h). Uninfected (−) and DENV-infected (+) A549 or IRF9 KO cells were analyzed by Western blotting for IRF9, IRAV, or IFIT3. GAPDH was used as a loading control. (C) Western blot analysis of IRAV expression in control A549 or IRF9 KO cells after treatment with IFN-β. The cells were either left untreated (−) or treated with IFN-β (+) for 16 h, followed by Western blot analysis for expression of IRF9, IRAV, or IFIT3. GAPDH was used as a loading control. (D) Western blot analysis of IRAV expression in HeLa cells after treatment with 10-fold dilutions of IFN-β (30 to 0.00003 ng/ml) for 16 h. Samples were examined by Western blotting for expression of IRAV and IFIT3. GAPDH was used as a loading control. (E) Western blot analysis of IRAV expression in HeLa cells after treatment with IFN-β (3 ng/ml) at the indicated time points. Samples were examined by Western blotting for expression of IRAV and IFIT3. GAPDH was used as a loading control. (F) Western blot analysis of IRAV expression in various cell lines. The indicated cell lines were either left untreated (−) or treated with IFN-β (+) (10 ng/ml) for 16 h, followed by Western blot analysis for IRAV. Actin was used as a loading control.