ATF3 and infection: Notably, all of the upregulated genes (Atf3, Fosb, Nur77, Nurr1 and Arc) belong to the class of Immediate Early (IE) response genes that are rapidly co-induced in multiple cell types in response to external stimuli, such as infection and inflammatory signals (Wilson et al., 2010; Bahrami and Drablos, 2016; Crean and Murphy, 2021).