CA-MDA5 mutants increase endogenous IFNβ mRNA expression. Control empty vector, WT, or CA-MDA5 were expressed in HEK293T cells. Total RNA was harvested and analyzed by RT-qPCR. Data are representative of ≥3 replicate experiments and are shown normalized to GAPDH expression. Bars indicate average values of technical replicates (n = 3) with error bars representing standard deviation. Statistical analysis was done using a 2-tailed Student's t-test (*P < 0.05, **P < 0.005). mRNA, messenger RNA; RT-qPCR, reverse transcription–quantitative polymerase chain reaction.