title: Diversity and structure of human T-cell receptor alpha-chain variable region genes.
abstract: The nucleotide sequences of 27 T-cell receptor alpha-chain variable region (V alpha)-containing cDNA clones isolated from a cDNA library derived from human peripheral blood lymphocytes were determined. Eighteen different V alpha and 26 different joining (J alpha) gene segments are utilized in these clones. The V alpha gene segments belong to 12 different subfamilies, each containing from one to seven members. Comparisons with the 16 different V alpha and 21 different J alpha sequences previously reported suggest that the germ-line repertoires for these gene segments are greater than previously estimated. Flexibility in the sites of gene segment joining and possibly N-region diversification also contribute to human alpha-chain diversity. Comparisons of human V alpha regions indicate a high degree of variability spread uniformly across the entire V alpha region without obvious hypervariable regions. However, amino acids important for the maintenance of V gene structure are conserved.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D005796:Genes; D014644:Genetic Variation; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D004247:DNA