Fig. 2

a Induction of IFN-υ gene by GCRV. Zebrafish larvae (5 dpf, n = 33) were infected with GCRV for 24 h and were collected to extract RNA to determine the expression of ifnu, which was normalized against gapdh, by using quantitative RT-PCR. b Induction of anti-viral ISGs in IFN-υ-stimulated zebrafish. Embryos (n = 150) were injected at one-cell stage with IFN-υ or empty vector plasmid, and after 72 h, the mRNA level of ISGs was detected by quantitative RT-PCR. The expression of the selected genes was normalized against gapdh and fold changes were calculated relative to control group (empty vector). c Analyses of viral titers in IFN-υ-stimulated zebrafish. Embryos (n = 150) at one-cell stage were expressed with IFN-υ plasmid or empty vector for 72 h, and the hatched zebrafish larvae (n = 33) were infected with GCRV for 24 h and then collected to detect viral titers. Effects of IFN-υ deficiency on ISG expression, such as gig2 (d), irf1 (e), mxa (f) and viperin (g), and viral titers (h) in response to GCRV infection. 5 dpf zebrafish (n = 33) were infected with GCRV for 24 h and then were collected to determine ISG expression and viral titer. The expression of the selected genes was normalized against gapdh. Data are expressed as mean ± SEM from three independent experiments. The two-tailed Student’s t test was used to determine the statistical significance, with * indicating P < 0.05, and ** indicating P < 0.01.