Crucial role of the pre-T-cell receptor alpha gene in development of alpha beta but not gamma delta T cells

In T-cell precursors, the T-cell-receptor beta chain is expressed before the T-cell-receptor alpha chain [1,2] and is sufficient to advance T-cell development in the absence of T-cell receptor alpha chains [3-7]. In immature T cells, the T-cell-receptor beta protein can form disulphide-linked heterodimers with the pre-T-cell-receptor alpha chain [8,9] and associate with signal-transducing CD3 molecules [5]. The recently cloned pre-T-cell-receptor alpha gene encodes a transmembrane protein that is expressed in immature but not mature T cells [9,10]. Here we show that alpha beta, but not gamma delta, cell development is severely hampered in pre-T-cell-receptor alpha-gene-deficient mice, which establishes a crucial role for the pre-T-cell receptor in early thymocyte development.