CLONING OF CDNAS AND THE MOLECULAR EVOLUTION OF A BOVINE MHC CLASS-IIDRA GENE

Two overlapping cDNA clones coding for bovine major histocompatibility complex (MKC) class II antigen DRA chain were isolated and characteri zed. The full-length cDNA clone, MR1, encoded a primary translated pro duct of 253 amino acids, 24 of which were deduced to be a signal pepti de and 229 which formed a mature polypeptide. The amino acid sequences deduced from this clone resembled those of class II A molecules from other species in both size and structure, but no potential consensus s ite of N-linked glycosylation comparable to those in the human, mouse, rat and swine proteins was found in the alpha 2 domain, as well as ov ine and equine DRA molecules. Comparison of amino acid sequences encod ed by class II A genes among several species and a dendrogram construc ted from these data places the DRA gene and the DQA/DYA genes on two d istinct branches of a phylogenetic tree, with bovine DRA and ovine DRA being most similar on the DRA branch. (C) 1994 Academic Press, Inc.