title: Regions of allelic hypervariability in the murine A alpha immune response gene.
abstract: The murine Ia antigens, a group of cell surface glycoproteins, are involved in the control of the immune response. The structure of one of these class II major histocompatibility complex molecules, A alpha, was recently deduced from sequence analysis of a cDNA clone produced from k haplotype mice. We have now isolated and sequenced A alpha cDNA clones from five other mouse haplotypes: d, b, f, u, and q. Sequence comparison revealed a surprisingly high degree of allelic polymorphism. Interestingly, amino acid substitutions were clustered within the first external domain of this polypeptide chain, particularly at a few highly variable positions. Functional implications of A alpha polymorphism and possible mechanisms for its generation are discussed.
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II; D051379:Mice; D008807:Mice, Inbred BALB C; D011110:Polymorphism, Genetic
chemical_list: D004274:DNA, Recombinant; D000949:Histocompatibility Antigens Class II; D004247:DNA; D004262:DNA Restriction Enzymes