As expected from previous studies [11], [12], [13], [14], over-expression of the MAVS protein strongly induced the expression of endogenous IFNβ in control MEFs, even in the absence of viral infection, and SeV-induced IFNβ expression was enhanced in cells in which MAVS was over-expressed (Fig. 3A). This evidence concerns the gene IFNB1 and viral infectious disease.