Genes that encode the component polypeptides of T cell receptors (q.v.). There are two types of receptors: those containing an alpha and a beta chain, and those containing a delta and a gamma chain. In humans, both the alpha and the gamma chains are encoded by genes on the long arm of chromosome 14. The beta chain gene is located on the long arm of chromosome 7, and the gamma chain gene resides on the short arm of chromosome 7. As in the case of the immunoglobulins, the T cell receptor polypeptide chains are encoded by gene segments that are reshuffled during the differentiation of the precursor cells. The rearrangement of segments occurs in thymocytes before the genes encoding the polypeptides are expressed. As a result, T cell receptors have more than 107 different amino acid sequences. See Chronology, 1984, Davis and Mak; V(D)J recombination.
Subjects: Genetics and Genomics.