Fig. 5

ZIKV NS4A negatively regulates IFN production. a Lysates of 293T cells co-transfected with RIG-I(N), IFN-β reporter, together with ZIKV NS4A (250, or 500 ng), DENV NS4A (250, or 500 ng), ZIKV prM (500 ng) or PB1-F2 (500 ng)were analyzed for luciferase activity. 293T cells were transfected with IFN-β reporter, together with ZIKV NS4A (250, or 500 ng), DENV NS4A (250, or 500 ng), ZIKV prM (500 ng) or PB1-F2 (500 ng), b then infected with SeV at 100 HAU/ml for 24 h, c or transfected with 20 μg/ml of poly(I:C) for 24 h followed by analysis of the cell lysates for luciferase activity. d, e HFF-1 cells or f PBMC were transfected with blank control vector or a vector expressing ZIKV NS4A (500 ng), DENV NS4A (500 ng), ZIKV prM (500 ng) or PB1-F2 (500 ng), respectively, and 24 h later were mock-infected or infected with SeV at 100 HAU/ml or transfected with or without 20 μg/ml of poly(I:C) for 24 h, followed by analysis of the supernatant for IFN-β protein levels. g, h Meanwhile, at 24 h post-infection, total cellular RNA was isolated, and real-time PCR was performed to detect IFNB, OAS1, and IFITM1 mRNA levels in 293T cells. The data are presented as the mean ± SD derived from three repeat experiments. *p < 0.05, and **p < 0.01 (Student’s t-test)