Diversity of the mouse T cell receptor Cγ1 gene: structural analysis in C57BL/Ka

We have isolated an unusual T cell receptor γ chain cDNA clone (γ7.1) from a library made from RNA derived from adult thymus of C57BL/Ka mice. This cDNA clone corresponds to the appropriately processed Cγ1 constant region exons preceded by 1.5 kb of J-Cγ1 intron. The γ7.1 coding region is extremely homologous to the Cγ1 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-Cγ1 intronic region contains two DNA segments (termed ΨJγ1 and ΨJγ2) 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 γ7.1 may be derived from a large, variable region-containing precursor.