Evolutionary conservation and antiviral effect of interferon regulatory factor 1 (IRF1) in Tibetan frog Nanorana parkeri

Interferon regulatory factor 1 (IRF1) is considered to be a vital regulator of antiviral immune responses, and the knowledge on functions of IRF1 in antiviral defense is rather limited in amphibians, which have undergone worldwide declines due to the prevalence of ranavirus infections. In the present study, an IRF1 gene named as Np-IRF1 was identified and characterized in Tibetan frog (Nanorana parkeri). Bioinformatic analysis revealed that Np-IRF1 and IRF1 from different species of vertebrates have a conserved genomic organization of eight exons and nine introns, and locate a conserved genomic region. Expression analysis showed that Np-IRF1 gene was widely expressed and induced by poly(I:C) in different organs/tissues. Moreover, the overexpression of Np-IRF1 could induce the expression of interferon-stimulated genes, and reduce the CPE and viral loads in ranavirus-infected A6 cells. The present research thus contributes to a better understanding of regulatory function of IRF1 in the antiviral immune responses of anuran amphibians.