Tbt-1, a new T-Box transcription factor induced in activated Th1 and CD8+ T cells
Tbt-1 (T-box protein expressed in T lymphocytes) is a Th1-specific transcription factor. Tbt-1 is a member of the T-box family, which is characterized by a conserved T-box DNA-binding domain.
Unlike other known T-box proteins that regulate embryo development and organogenesis, Tbt-1 expression is restrited to adult lymphoid organs.
Tbt-1 mRNA is only detected in peripheral lymphoid tissues such as spleen, lymph nodes, and blood leukocytes, but not in thymus or bone marrow. Tbt-1 mRNA is not detected in resting T cells and but is strongly induced in differentiating Th1 cells and CD8+ cytotoxic effector cells. In constrast, Tbt-1 expression was not observed in the entire process of Th 2 cell differentiation.
Tbt-1 is the first T-box transcription factor shown to be specific for Th 1 cell differentiation .