TBX21

Function

This gene is a member of a phylogenetically conserved family of genes that share a common DNA-binding domain, the T-box. T-box genes encode transcription factors involved in the regulation of developmental processes. This gene is the human ortholog of mouse Tbx21/Tbet gene. Studies in mouse show that Tbx21 protein is a Th1 cell-specific transcription factor that controls the expression of the hallmark Th1 cytokine, interferon-gamma (IFNG). Expression of the human ortholog also correlates with IFNG expression in Th1 and natural killer cells, suggesting a role for this gene in initiating Th1 lineage development from naive Th precursor cells.

Asthma

The transcription factor encoded by TBX21 is T-bet, which regulates the development of naive T lymphocytes. Asthma is a disease of chronic inflammation, and it is known that transgenic mice born without TBX21 spontaneously develop abnormal lung function consistent with asthma. It is thought that TBX21, therefore, may play a role in the development of asthma in humans as well.