Consistent with the observation from the siRNA knockdown or sgRNA knockout of PRMT9, infection of Prmt9CKO peritoneal macrophages with SeV or stimulation with 5’PPP RNA led to a significant increase in the expression of Ifnb1, Ifnα4, and Cxcl10 mRNA compared with that in Prmt9WT macrophages (Fig. 2a, b). Here, IFNA4 is linked to infection.