title: Molecular cloning and characterization of sea bass (Dicentrarchus labrax, L.) MHC class I heavy chain and β2-microglobulin.
abstract: In this work, the gene and cDNA of sea bass (Dicentrarchus labrax) β2-microglobulin (Dila-β2m) and several cDNAs of MHC class I heavy chain (Dila-UA) were characterized. While Dila-β2m is single-copy, numerous Dila-UA transcripts were identified per individual with variability at the peptide-binding domain (PBD), but also with unexpected diversity from the connective peptide (CP) through the 3' untranslated region (UTR). Phylogenetic analysis segregates Dila-β2m and Dila-UA into each subfamily cluster, placing them in the fish class and branching Dila-MHC-I with lineage U. The α1 domains resemble those of the recently proposed L1 trans-species lineage. Although no Dila-specific α1, α2 or α3 sub-lineages could be observed, two highly distinct sub-lineages were identified at the CP/TM/CYT regions. The three-dimensional homology model of sea bass MHC-I complex is consistent with other characterized vertebrate structures. Furthermore, basal tissue-specific expression profiles were determined for both molecules, and expression of β2m was evaluated after poly I:C stimulus. Results suggest these molecules are orthologues of other β2m and teleost classical MHC-I and their basic structure is evolutionarily conserved, providing relevant information for further studies on antigen presentation in this fish species.
authors.affiliation: Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, Porto, Portugal. rsp@ibmc.up.pt
authors.forename: Rute D
authors.initials: RD
authors.lastname: Pinto
authors.forename: Elisa
authors.initials: E
authors.lastname: Randelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Buonocore
authors.forename: Pedro J B
authors.initials: PJ
authors.lastname: Pereira
authors.forename: Nuno M S
authors.initials: NM
authors.lastname: dos Santos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001492:Bass / Q000276:immunology*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000276:immunology; D060226:Head Kidney / Q000166:cytology / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D007962:Leukocytes / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D011070:Poly I-C / Q000276:immunology; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D001613:beta 2-Microglobulin / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D015395:Histocompatibility Antigens Class I; D001613:beta 2-Microglobulin; D011070:Poly I-C