title: The identification of additional zebrafish DICP genes reveals haplotype variation and linkage to MHC class I genes.
abstract: Bony fish encode multiple multi-gene families of membrane receptors that are comprised of immunoglobulin (Ig) domains and are predicted to function in innate immunity. One of these families, the diverse immunoglobulin (Ig) domain-containing protein (DICP) genes, maps to three chromosomal loci in zebrafish. Most DICPs possess one or two Ig ectodomains and include membrane-bound and secreted forms. Membrane-bound DICPs include putative inhibitory and activating receptors. Recombinant DICP Ig domains bind lipids with varying specificity, a characteristic shared with mammalian CD300 and TREM family members. Numerous DICP transcripts amplified from different lines of zebrafish did not match the zebrafish reference genome sequence suggesting polymorphic and haplotypic variation. The expression of DICPs in three different lines of zebrafish has been characterized employing PCR-based strategies. Certain DICPs exhibit restricted expression in adult tissues whereas others are expressed ubiquitously. Transcripts of a subset of DICPs can be detected during embryonic development suggesting roles in embryonic immunity or other developmental processes. Transcripts representing 11 previously uncharacterized DICP sequences were identified. The assignment of two of these sequences to an unplaced genomic scaffold resulted in the identification of an alternative DICP haplotype that is linked to a MHC class I Z lineage haplotype on zebrafish chromosome 3. The linkage of DICP and MHC class I genes also is observable in the genomes of the related grass carp (Ctenopharyngodon idellus) and common carp (Cyprinus carpio) suggesting that this is a shared character with the last common Cyprinidae ancestor.
authors.affiliation: Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Rodriguez-Nunez
authors.affiliation: Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA.
authors.forename: Dustin J
authors.initials: DJ
authors.lastname: Wcisel
authors.affiliation: Department of Pediatrics, University of South Florida Morsani College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL, 33701, USA.
authors.forename: Ronda T
authors.initials: RT
authors.lastname: Litman
authors.affiliation: Department of Pediatrics, University of South Florida Morsani College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL, 33701, USA.|Department of Molecular Genetics, All Children's Hospital Johns Hopkins Medicine, 501 6th Avenue South, St. Petersburg, FL, 33701, USA.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Litman
authors.affiliation: Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA. Jeff_Yoder@ncsu.edu.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Yoder
mesh_terms: D000818:Animals; D018507:Gene Expression Regulation, Developmental; D005805:Genes, MHC Class I / Q000235:genetics* / Q000276:immunology; D008040:Genetic Linkage; D006239:Haplotypes; D007113:Immunity, Innate; D007136:Immunoglobulins / Q000235:genetics*; D008055:Lipids / Q000235:genetics; D011971:Receptors, Immunologic / Q000235:genetics* / Q000276:immunology; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D029961:Zebrafish Proteins / Q000235:genetics* / Q000276:immunology
chemical_list: C574864:DICP1.1 protein, zebrafish; D007136:Immunoglobulins; D008055:Lipids; D011971:Receptors, Immunologic; D029961:Zebrafish Proteins
keywords: Haplotype; Immune receptor; Immunoglobulin domain; Innate immunity; Polymorphism