IRF1 and infection: Among the genes positively regulated by IRF1 signalling and directly bound by IRF1, we found the already known targets, guanylate-binding protein 2 (Gbp2) and Gbp5 (refs 50, 51), which contribute to clearance of infection as well as Th1-associated genes, including Il12rb1 (refs 1, 36; Fig. 4f).