Diversity of the mouse T cell receptor C gamma 1 gene: structural analysis in C57BL/Ka.

We have isolated an unusual T cell receptor gamma chain cDNA clone (gamma 7.1) from a library made from RNA derived from adult thymus of C57BL/Ka mice. This cDNA clone corresponds to the appropriately processed C gamma 1 constant region exons preceded by 1.5 kb of J-C gamma 1 intron. The gamma 7.1 coding region is extremely homologous to the C gamma 1 gene of BALB/c mice, differing at the protein level by a single deletion (alanine 139) and a single substitution. This latter change eliminates the sole N-linked sugar attachment site, providing a basis for strain-specific glycosylation patterns. The J-C gamma 1 intronic region contains two DNA segments (termed psi J gamma 1 and psi J gamma 2) that are highly reminiscent of joining (J) segments; both have potentially functional recombination and donor splice sequences flanking an open reading frame. Northern analysis suggests that gamma 7.1 may be derived from a large, variable region-containing precursor.