Abstract

An inducible program of inflammatory gene expression is a hallmark of antimicrobial defenses. Herein, we identified Cellular nucleic acid binding protein (Cnbp) as a specific regulator of interleukin-12{beta} gene transcription and Th1 immunity. Cnbp resides in the cytosol of macrophages and translocates to the nucleus in response to a broad range of microbial ligands. Cnbp-deficient macrophages had a selective impairment in their ability to induce IL12{beta} gene transcription. Cnbp interacted with c-Rel, an NF{kappa}B/Rel family member that controls IL12{beta} gene transcription. c-Rel nuclear translocation and DNA binding activity were dependent on Cnbp. Furthermore, Cnbp itself bound the IL12{beta} promoter. Lastly, Cnbp-deficient mice were more susceptible to acute toxoplasmosis associated with reduced production of IL12{beta}, as well as a reduced Th1 cell IFN{gamma} response essential to control parasite replication. Collectively, these findings identify Cnbp as a key regulator of c-Rel dependent IL12{beta} gene transcription and Th1 immunity.