dsRNA length-dependent induction of IFN-β correlates with PKR-dependent reduction in IκB-α protein and eIF-2α phosphorylation.
A, relative IFN-β induction measured by quantitative PCR (qPCR) using RNA extracted 5 h following incubation with lipid alone (NT) or RNA transfection in parental PKR+ HeLa cells. IFN-β mRNA levels were normalized to GAPDH using the ΔΔCT method. Standard deviation determined from three independent experiments. B, Western blot for IκB-α, phosphorylated eIF-2α (P-eIF-2α) and total eIF-2α, and α-tubulin loading control, at 4 h and 8 h following transfection of either parental PKR+ or knockdown PKRkd HeLa cells with the indicated dsRNA. C, quantitation of IκB-α protein level normalized to α-tubulin and compared with cells not transfected (NT). Mean and standard deviation determined from two independent experiments. *, p < 0.05 compared with NT and Pds20 at the corresponding time point in PKR+ cells, **, p < 0.01 compared with NT and Pds20.