Induction of IFN and IFN-stimulated genes is inhibited by reduction of RIG-I but not PKR.

<p>A549cells were first transfected with the siRNAs against RIG-I or PKR(3 µg)as shown or mock transfected. 24 hr later, the cells were transfected again with the indicated IVT RNAs (3 µg) and processed 24 hr later for RNA as well as protein. Protein lysates are used to determine the levels of PKR and RIG-I proteins by western blot analyses and RNA is used to determine the levels of mRNA for IFN-β. (A) Western blots using the indicated antibodies of protein extracts from treated cells are shown. (B) and (C) IFN-β mRNA levels were measured using qRT-PCR. Error bars represent the standard deviation of triplicate qRT-PCR runs using RNAs from one of three representative experiments.