Mouse T cell antigen receptor: Structure and organization of constant and joining gene segments encoding the β polypeptide

The germ-line joining (J) gene segments and constant (C) genes encoding the β chain of the mouse T cell antigen receptor have been isolated on a single cosmid clone. There are two constant genes, C_β1 and C_β2, each associated with a cluster of J_β gene segments. The nucleotide sequences of the C_β2 gene and of the J_β2 cluster gene segments have been determined. The coding sequence of the C_β2 gene is very similar to the sequence of a cDNA clone encoded by the C_β1 gene. The C_β2 gene has four exons; exon-intron structure does not obviously correspond to the functional domains of the protein. The J_β2 gene segment cluster contains six functional J gene segments. We have isolated specific probes for the C_β1, C_β2, J_β1, and J_β2 regions to examine DNA rearrangements in T lymphocytes. DNA rearrangements can occur in both J_β gene segment clusters, and both C_β genes appear functional.