CNBP controls IL-12 gene transcription and Th1 immunity

An inducible program of inflammatory gene expression is a hallmark of antimicrobial defenses. Recently, cellular nucleic acid-binding protein (CNBP) was identified as a regulator of nuclear factor-kappaB (NF-kappa B)-dependent proinflammatory cytokine gene expression. Here, we generated mice lacking CNBP and found that CNBP regulates a very restricted gene signature that includes IL-12 beta. CNBP resides in the cytosol of macrophages and translocates to the nucleus in response to diverse microbial pathogens and pathogen-derived products. Cnbp-deficient macrophages induced canonical NF-kappa B/Ret signaling normally but were impaired in their ability to control the activation of c-Rel, a key driver of IL-12 beta gene transcription. The nuclear translocation and DNA-binding activity of c-Rel required CNBP. Lastly, Cnbp-deficient mice were more susceptible to acute toxoplasmosis associated with reduced production of IL-12 beta, as well as a reduced T helper type 1 (Th1) cell IFN-y response essential to controlling parasite replication. Collectively, these findings identify CNBP as important regulator of c-Ret-dependent IL-12 beta gene transcription and Th1 immunity.