T Cell Receptor g Gene Regulatory Sequences Prevent the Function of a Novel TCRg/pTa Pre–T Cell Receptor

and Cancer Research Laboratory ment, wherein cells destined to develop into ab T cells Division of Immunology must express a functional TCRb chain in order to effiUniversity of California at Berkeley ciently proceed to the CD252CD442 stage (Mombaerts Berkeley, California 94720 et al., 1992a; Shinkai et al., 1993; Dudley et al., 1994; †Basel Institute for Immunology Fehling et al., 1995). The successful TCRb cells proliferCH-4005 Basel ate extensively and differentiate into immature ab linSwitzerland eage CD41CD81 (double positive [DP]) thymocytes. ‡Centre d’Immunologic CD25CD44 TN cells can also differentiate into Institut National de la Sante CD4CD8 (double negative [DN]) gd thymocytes if both et de la Recherche Medicale TCRg and TCRd genes are rearranged productively. This Centre National de la Recherche Scientifique process differs in important ways from ab T cell developde Marseille-Luminy ment. First, TCRg and d genes undergo rearrangement 13288 Marseille Cedex 9 more or less coordinately, whereas b genes are reFrance arranged considerably before the a genes (Godfrey et