title: Polymorphism of two very similar MHC class Ib loci in rainbow trout (Oncorhynchus mykiss).
abstract: As part of an ongoing elucidation of rainbow trout major histocompatibility complex (MHC) class I, the polymorphism of two MHC class Ib loci was analyzed. These loci, Onmy-UCA and Onmy-UDA, are situated head-to-tail and share more than 89% nucleotide identity in their open reading frames. They share 80% identity with some trout Ia alleles. The deduced amino acid sequences suggest that the UCA and UDA molecules are transported to endosomal compartments and may bind peptides in their binding groove. Our survey revealed seven UCA and eight UDA alleles. Similarity indices overlap when comparing within and between UCA and UDA alleles and some cross-locus motif variation is observed. In most trout both UCA and UDA transcripts were found. However, there probably is functional redundancy, because some trout lacked transcription of one of the two loci. Furthermore, for some UCA and UDA alleles, splicing deficiencies, early stop codons, and upstream start codons were found, which may interfere with efficient protein expression. The present study is the first extensive report on MHC class Ib polymorphism assigned to locus in ectotherm species.
authors.affiliation: Inland Station, Fisheries Research Agency, National Research Institute of Aquaculture, Tamaki, Mie 519-0423, Japan. dijkstra@fujita-hu.ac.jp
authors.forename: Johannes Martinus
authors.initials: JM
authors.lastname: Dijkstra
authors.forename: Ikunari
authors.initials: I
authors.lastname: Kiryu
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Yoshiura
authors.forename: Attila
authors.initials: A
authors.lastname: Kumánovics
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kohara
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Hayashi
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ototake
mesh_terms: D020413:3' Untranslated Regions; D000483:Alleles; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D021461:Animals, Outbred Strains / Q000235:genetics; D001483:Base Sequence; D016827:CD8 Antigens / Q000276:immunology; D018389:Codon, Nonsense; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D020440:Gene Duplication; D005805:Genes, MHC Class I / Q000235:genetics*; D016678:Genome / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000276:immunology*; D011110:Polymorphism, Genetic; D014176:Protein Biosynthesis / Q000235:genetics; D011487:Protein Conformation; D011544:Pseudogenes / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D020413:3' Untranslated Regions; D016827:CD8 Antigens; D018389:Codon, Nonsense; D018076:DNA, Complementary; D015395:Histocompatibility Antigens Class I