Fig 3.

IFN mediates regulation of miR-203. (A) A549 cells were mock infected or infected with either influenza virus A/Udorn/72 (Udorn), A/WSN/33 (WSN), or Sendai virus Cantell Strain (Sendai) (5 PFU/cell; 10 h). RNA was purified at 10 h postinfection and size fractionated to yield RNA of <200 nucleotides in length, and the abundances of miR-203, miR-449b, and miR-16 were analyzed using TaqMan miRNA RT-qPCR assays. (B) High-molecular-weight RNA was used to measure the abundance of IFN-β mRNA during Sendai virus and influenza virus infection by RT-qPCR as indicated. (C) A549 cells were left untreated (UNT) or treated with PBS or increasing concentrations of IFN-α (250 units/ml, 500 units/ml, 1,000 units/ml, or 5,000 units/ml). RNA was purified at 10 h posttreatment, and the abundance of miR-203 was analyzed by TaqMan miRNA assays. (D) A549 cells were left untreated or treated as indicated with PBS or IFN-α (1,000 units/ml) and mock infected or infected with Sendai virus (5 PFU/cell). RNA was purified at 10 h posttreatment, and the abundance of miR-203 was analyzed by TaqMan miRNA assays. (E) A549 cells were left untreated, treated with PBS or IFN-α (1,000 units/ml), or transfected with poly(I·C) (5 μg/ml). RNA was purified at 10 h posttreatment, and the abundance of miR-203 was analyzed by TaqMan miRNA assays. (F) Vero cells were left untreated or treated as indicated with PBS or IFN-α (1,000 units/ml) and then mock infected or infected with Sendai virus (5 PFU/cell). RNA was purified at 10 h posttreatment, and the abundance of miR-203 was analyzed by TaqMan miRNA assays. Statistical significance was determined by a two-tailed t test (*, P < 0.05; **, P < 0.01; ***, P < 0.001; n.s., not significant).