CRUCIAL ROLE OF THE PRE-T-CELL RECEPTOR-ALPHA GENE IN DEVELOPMENT OF ALPHA-BETA BUT NOT GAMMA-DELTA T-CELLS

T-cell precursors, the T-cell-receptor B 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 a 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.