CGAS and infection: Although knockdown of DDX41 in D2SC cells, a mouse myeloid DC line, has no effect on influenza virus-induced IFN-α/β production41, we found that IFN-β gene expression was significantly reduced in DDX41 knockdown HEK293FT or cGAS-293FT cells after infection with WT or ΔNS1 influenza virus (Fig. 5a and Supplementary Fig. 11c, d).