IRF7 and infection: The expression of RIG-I signaling or antiviral response-related genes, such as DDX58 (RIG-I dsRNA sensing), IFIH1 (MDA-5 dsRNA sensing), IRF-7 (IFN regulatory factor 7; activates both IFN-α and IFN-β), UBA7 (ubiquitin activating enzyme that catalyzes ISGylation of targeted proteins), and HERC5 (ubiquitin protein ligase that mediates ISGylation of targeted proteins) were significantly elevated after infection by all recombinant influenza Cal viruses (Fig 5A).