A ligase within the PIAS family is responsible for the sumoylation of IRF3 and IRF7 observed after a viral infection, leading to the negative regulation of type I IFN gene expression, and PIAS1 is a mediator of IRF7 sumoylation (Kubota et al., 2008; Chang et al., 2009). This evidence concerns the gene IRF3 and viral infectious disease.