The V protein of PPRV blocks the induction of IFN-β by intracellular poly(I:C).

<p>(A) VHS cells were transfected with pIFN-β-luc (350 ng), pJAT-lacZ (200 ng), pEF-MDA-5 (100 ng) and an empty plasmid (500 ng) or expression plasmid encoding PIV5 V (500 ng), RPV V (300 ng) or PPRV V (500 ng). The total amount of DNA was kept constant in all samples by adding empty plasmid as required. At least twenty four hours post transfection, cells were transfected with 2 μg of poly(I:C) or left untreated; 7 hours later the cells were lysed and the cells extracts were assayed for luciferase and β-galactosidase activities. Samples were normalised by setting RLUs in poly(I:C) transfected cells without V protein to 100. Error bars represent the standard error of the mean. ANOVA and Tukey pairwise comparison test were used to determine the statistical significance of differences in means (* = p < 0.05). (B) Cell extracts from parallel transfected wells were run on 10% SDS-PAGE gels and Western blotted with anti-V5 or anti-PCNA (loading control).