title: Character of chicken polymorphic major histocompatibility complex class II alleles of 3 Chinese local breeds.
abstract: To better understand the major histocompatibility complex (MHC) genetic character of domestic birds, we sequenced and analyzed chicken MHC II (B-L) genes of 3 local chicken breeds, derived from 3 separate areas in China. We amplified cDNA sequences from 105 individuals, accounting for 35 alleles. Some of the same B-LB alleles with a high frequency were found in all samples. The putative B-L α-chain had few polymorphic sites, whereas the B-L β-chain had several polymorphic sites. Most of the mutation positions were located in the B-LB β1 domain encoded by exon 2, especially in the peptide-binding region. This indicated that the highly polymorphic peptide-binding region could potentiate binding diverse antigen epitopes. The comparison of 3-D molecule structures of chicken B-L and human HLA-DR1 revealed a distinctly structural similarity, but the chicken B-L molecule had more polymorphic sites than the human HLA-DR1 molecule, which presumably might be a mechanism to compensate for responding to a wider array of pathogens due to fewer loci for chicken. Moreover, some conserved sites in human and chicken MHC class II molecules reflected their common ancestry and similar functions. These results suggest that the chicken B-L gene showed more polymorphic sites and distinctly dominant trans-breed alleles, potentially to adapt to pathogens.
authors.affiliation: Anhui Agricultural University, Hefei 230036, China.
authors.forename: F
authors.initials: F
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Pan
authors.forename: W
authors.initials: W
authors.lastname: Chao
authors.forename: Y
authors.initials: Y
authors.lastname: Dai
authors.forename: W
authors.initials: W
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000235:genetics*; D002681:China; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D012313:RNA / Q000235:genetics / Q000378:metabolism
chemical_list: D012313:RNA