FIG 4.

PACT and RIG-I augment IFN-β induction by MV DI RNA and the Hu-191 virus. (A) Plasmids expressing the indicated combinations of RIG-I, MDA5, and PACT were transfected into HEK293 cells. After 48 h, in vitro-transcribed MV DI RNA was further transfected. The levels of IFN-β and GAPDH mRNA were measured by quantitative real-time RT-PCR after 6 h. The level of IFN-β mRNA expression relative to the level of expression of the GAPDH mRNA transcript in a mock-transfected control sample was taken as 1. Results are the means from three independent experiments, and error bars indicate SDs. The difference between the samples whose results are shown as bars 3 and 6 was statistically significant, as determined by a two-tailed Student's t test with a P value equal to 0.0089 (highlighted by **). (B) The same transfection described in the legend to panel A was performed in SLAM-expressing A549 cells. After 48 h, cells were infected with the Hu-191 virus at a multiplicity of infection of 0.5 for 18 h. Error bars denote SDs from three independent experiments. The difference between the samples whose results are shown as bars 3 and 6 was statistically significant, as determined by two-tailed Student's t test with a P value equal to 0.0054 (highlighted by **).