IFNB1 and infection: We recently generated knock-in mice in which wild type Pellino1 was replaced by an E3 ligase-deficient mutant (Pellino1[F397A]) and exploited them to demonstrate that Pellino1 is required for the production of IFNβ induced by the TLR3 ligand poly(I:C) in myeloid cells, or by infection with Sendai virus in mouse embryonic fibroblasts (MEFs) (9).