Transcriptional expression of tilapia Mx and Viperin is differentially regulated by three subgroups of type I IFNs mainly via the JAK-STAT signaling.

The antiviral effects of the interferons (IFNs) depend on the induction of a variety of antiviral interferon-stimulated genes (ISGs), among which the myxovirus resistance protein (Mx) and the virus inhibitory protein, endoplasmic reticulum associated, interferon inducible (Viperin) are two well-characterized antiviral ISGs. However, the different transcriptional regulation of Mx and Viperin, as well as their differential responses to distinct subgroups of type I IFNs across various fish species, still await extensive comparative investigation. Here, we cloned Mx and Viperin genes (named as On-Mx and On-Viperin) from tilapia. Expression comparison showed that On-Mx and On-Viperin was detectable in all organs/tissues tested, and was highly induced after poly (I:C) treatment or NNV infection in vivo and in vitro. Importantly, the expression and promoter activities of On-Mx and On-Viperin were differentially induced by IFNc, IFNd, and IFNh mainly via the JAK-STAT signaling, with IFNc exhibiting a stronger inductive effect than IFNd and IFNh. The present results thus improve the understanding of the transcriptional regulation of fish Mx and Viperin in type I IFN response.