The human T-cell rearranging gamma (TRG) genes and the gamma T-cell receptor.
The human T-cell Rearranging Gamma genes or T-cell Receptor Gamma (TRG) chain genes, like those encoding the T-cell Receptor (TcR) alpha and beta polypeptides, undergo rearrangements specifically in T-cells. The human TRG locus which has been mapped to chromosome 7 (7p15) is composed of 2 constant region genes (TRGC), 5 joining segments (TRGJ) and at least 14 variable gamma genes (TRGV). 8 variable genes are functional and belong to 4 different subgroups. Based on restriction fragments, the TRG rearrangements can be assigned to given V and J segments, in normal T-cells, T leukemias and lymphomas. The product of the rearranged TRG gene is the gamma chain which is expressed at the surface of a subset of CD3+4-8- T lymphocytes lacking the conventional receptor alpha beta. Structural differences exist between the different 'gamma T-cell receptors', the gamma and delta polypeptides being disulfide or non-disulfide linked. Although the TRG+ cells display a cytolytic activity, their precise function remains to be elucidated.
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Laboratoire d'Immunogénétique, UA CNRS 1191, Génétique Moléculaire, Montpellier, France.
D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D015329:Gene Rearrangement, T-Lymphocyte; D005796:Genes; D005803:Genes, Immunoglobulin; D006801:Humans; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology*
D011948:Receptors, Antigen, T-Cell