title: Chemokine receptors in Atlantic salmon.
abstract: Teleost sequence data have revealed that many immune genes have evolved differently when compared to other vertebrates. Thus, each gene family needs functional studies to define the biological role of individual members within major species groups. Chemokine receptors, being excellent markers for various leukocyte subpopulations, are one such example where studies are needed to decipher individual gene function. The unique salmonid whole genome duplication that occurred approximately 95 million years ago has provided salmonids with many additional duplicates further adding to the complexity and diversity. Here we have performed a systematic study of these receptors in Atlantic salmon with particular focus on potential inflammatory receptors. Using the preliminary salmon genome data we identified 48 chemokine or chemokine-like receptors including orthologues to the ten receptors previously published in trout. We found expressed support for 40 of the bona fide salmon receptors. Eighteen of the chemokine receptors are duplicated, and when tested against a diploid sister group the majority were shown to be remnants of the 4R whole genome duplication with subsequent high sequence identity. The salmon chemokine receptor repertoire of 40 expressed bona fide genes is comparably larger than that found in humans with 23 receptors. Diversification has been a major driving force for these duplicate genes with the main variability residing in ligand binding and signalling domains.
authors.affiliation: Soeren Jaabaeksgate 10B, 0460 Oslo, Norway. Electronic address: unni.grimholt@gmail.com.
authors.forename: Unni
authors.initials: U
authors.lastname: Grimholt
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Helena
authors.initials: H
authors.lastname: Hauge
authors.affiliation: Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Anna Germundsson
authors.initials: AG
authors.lastname: Hauge
authors.affiliation: Centre for Biomedical Research, Department of Biology, University of Victoria, PO Box 3020 STN CSC, Victoria, Canada.
authors.forename: Jong
authors.initials: J
authors.lastname: Leong
authors.affiliation: Centre for Biomedical Research, Department of Biology, University of Victoria, PO Box 3020 STN CSC, Victoria, Canada.
authors.forename: Ben F
authors.initials: BF
authors.lastname: Koop
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002874:Chromosome Mapping; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000145:classification / Q000235:genetics*; D014644:Genetic Variation; D016678:Genome / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D019707:Receptors, Chemokine / Q000145:classification / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020317:Salmo salar / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D059467:Transcriptome / Q000235:genetics*
chemical_list: D029941:Fish Proteins; D019707:Receptors, Chemokine
keywords: Atlantic salmon; Chemokine receptors; Inflammation; Whole genome duplication