Nucleotide sequence of a light chain gene of the mouse I-A subregion: A beta d.

Ia (I region-associated) antigens are cell-surface glycoproteins involved in the regulation of immune responsiveness. They are composed of one heavy (alpha) and one light (beta) polypeptide chain. We have sequenced the gene encoding the A beta d chain of the BALB/c mouse. The presence of six exons is predicted by comparison with the complementary DNA sequences of human beta chains and with partial protein sequence data for the A beta d polypeptide. Sequence comparisons have been made to other proteins involved in immune responses and the consequent implications for the evolutionary relationships of these genes are discussed.