ANALYSIS AND EXPRESSION OF A CLONED PRE-T CELL-RECEPTOR GENE

The T cell antigen receptor (TCR) beta chain regulates early T cell de velopment in the absence of the TCR alpha chain. The developmentally c ontrolled gene described here encodes the pre-TCR alpha (pT alpha) cha in, which covalently associates with TCR beta and with the CD3 protein s forms a pre-TCR complex that transduces signals in immature thymocyt es. Unlike the lambda 5 pre-B cell receptor protein, the pT alpha chai n is a type I transmembrane protein whose cytoplasmic tail contains tw o potential phosphorylation sites and a Src homology 3 (SH3)-domain bi nding sequence. Pre-TCR alpha transfection experiments indicated that surface expression of the pre-TCR is controlled by additional developm entally regulated proteins. Identification of the pT alpha gene repres ents an essential step in the structure-function analysis of the pre-T CR complex.