Differential expression of two distinct T-cell receptors during thymocyte development.
The product of the T-cell receptor (TCR) gamma-gene has recently been found to be expressed on a subset of both peripheral cells and thymocytes. As an initial approach to understanding the role of this gamma-chain of TCR (TCR gamma) in T-cell development, we have studied the ontogeny of TCR expression at the protein level in the developing murine thymus. We show here that the first T3-associated TCR to be expressed in the developing thymus is a disulphide-linked heterodimer composed of a gamma-chain of relative molecular mass 35,000 (Mr 35K) and a 45K partner (termed TCR delta). This TCR gamma delta is first detected approximately two days before the appearance of cell-surface TCR alpha beta heterodimers. We report that N-glycosidase digestions reveal that all of the gamma-protein expressed on fetal thymocytes, as in adult CD4-8-(L3T4-, Lyt2-) thymocytes, bear N-linked carbohydrate side chains. The major gamma-gene transcribed in mature, alpha beta-bearing T cells (V gamma 1.2C gamma 2)encodes no N-linked glycosylation site so these results suggest that the fetal gamma delta receptor defines a distinct T-cell lineage whose development in the thymus precedes classical alpha beta-bearing cells.
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis; D051379:Mice; D008954:Models, Biological; D008970:Molecular Weight; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis* / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D011948:Receptors, Antigen, T-Cell