Fig. 5

Nuclear RIG-I restricts IAV infection. a, b A549 RIG-I KO cell lines inducibly expressing SLN-RIG-I, NES-RIG-I, NLS-RIG-I, or K270A-RIG-I were induced with 1 μg/mL Dox for 4 h, followed by infection with ΔNS1-ms (MOI = 1) for 14 h. The mRNA levels of IFNβ and IP10 (CXCL10) were determined by qRT-PCR. Relative mRNA expression was normalized to GAPDH mRNA levels and expressed using the ΔΔCt method relative to the SLN (with Dox but without infection) condition. c Inducible A549 RIG-I KO or RIG-I-MAVS DKO cell lines were induced as in a and b, and infected with ΔNS1-ms (MOI = 0.1) for 24 h. Expression levels of FLAG-RIG-I, MAVS, PB1, NP, and M1 were monitored by immunoblotting. d Virus titers in the culture supernatants from c were determined by plaque assay in MDCK-NS1 cells. Data are mean ± SD of three independent experiments. Significant differences were determined by one-way ANOVA followed by Tukey post-test (a, b) or an unpaired Student’s t-test (d). *p < 0.05, **p < 0.01, ****p < 0.0001; n.s. not significant