cDNA cloning, genomic structure and expression analysis of the goose (Anser cygnoides) MHC class I gene.

To provide data for studies on avian disease resistance, goose MHC class I cDNA (Ancy-MHC I) was cloned from a goose cDNA library, it's genomic structure and expression analysis were investigated. The mature peptides of Ancy-MHC I cDNA encoded 333 amino acids. The genomic organization is composed of eight exons and seven introns. Based on the genetic distance, six Ancy-MHC I genes from six individuals can be classified into four lineages. A total of nineteen amino acid positions in peptide-binding domain showed high scores by Wu-kabat index analysis. The Ancy-MHC I amino acid sequence displayed seven critical HLA-A2 amino acids that bind with antigen polypeptides, and have an 85.4-98.9% amino acid homology with each genes, and a 59.8-66.0% amino acid homology with chicken MHC class I. Expression analyses using Q-RT-PCR to detect the tissue-specific expression of Ancy-MHC I mRNA in an adult goose. The result appeared that Ancy-MHC I cDNA was expressed in the liver, spleen, intestine, kidney, lung, pancreas, heart, brain, and skin. The phylogenetic tree appears to branch in an order consistent with accepted evolutionary pathways.