IFNB1 and swine influenza: To further confirm the function of FBXW7 in vitro, we silenced FBXW7 in peritoneal macrophages with siRNA (Supplementary Fig. 3c) and detected the decreased expression of IFN-α4, IFN-β mRNA in FBXW7-silenced peritoneal macrophages upon VSV or H1N1 virus infection (Supplementary Fig. 3d).