Analysis and Expression of a Cloned Pre-T Cell Receptor Gene

The T cell antigen receptor (TCR) β chain regulates early T cell development in the absence of the TCRα chain. The developmentally controlled gene described here encodes the pre-TCRα (pTα) chain, which covalently associates with TCRβ and with the CD3 proteins forms a pre-TCR complex that transduces signals in immature thymocytes. Unlike the λ5 pre-B cell receptor protein, the pTα chain is a type I transmembrane protein whose cytoplasmic tail contains two potential phosphorylation sites and a Src homology 3 (SH3)-domain binding sequence. Pre-TCRα transfection experiments indicated that surface expression of the pre-TCR is controlled by additional developmentally regulated proteins. Identification of the pTα gene represents an essential step in the structure-function analysis of the pre-TCR complex.