T-Box Protein 21 (TBX21)

TBX21 expression correlates with IFNG expression in Th1 and natural killer (NK) cells. Ectopic expression of TBX21 both transactivated the IFNG gene and induced endogenous IFNG production. Retroviral gene transduction of TBX21 into polarized Th2 and Tc2 primary T cells redirected them into Th1 and Tc1 cells, respectively, as evidenced by the simultaneous induction of IFNG and repression of interleukin-4 (IL4) and interleukin-5 (IL5). The murine Tbx21 gene encodes a deduced 530-amino acid protein containing a 189-amino acid T-box DNA-binding domain that shows homology to murine Tbr1) and Xenopus eomesodermin (EOMES). The authors subsequently cloned human TBX21, which encodes a 535-amino acid protein that shares 88% amino acid identity with murine Tbx21.