title: Identification and characterisation of TLR18-21 genes in Atlantic salmon (Salmo salar).
abstract: Teleost fish possess many types of toll-like receptor (TLR) some of which exist in other vertebrate groups and some that do not (ie so-called "fish-specific" TLRs). In this study, we identified in Atlantic salmon (Salmo salar) whole-genome shotgun (WGS) contigs seven TLRs that are not found in mammals, including six types of fish-specific TLRs (one TLR18, one TLR19, and four TLR20 members (two of which are putative soluble forms (s)) and one TLR21. Phylogenetic analysis revealed that teleost TLR19-21 are closely related with murine TLR11-TLR13, whilst teleost TLR18 groups with mammalian TLR1, 2, 6 and 10. A typical TLR protein domain structure was found in all these TLRs with the exception of TLR20b(s) and TLR20c(s). TLR-GFP expression plasmids transfected into SHK-1 cells showed that salmon TLR19, TLR20a and TLR20d were preferentially localised to the intracellular compartment. Real time PCR analysis suggested that salmon TLR19-TLR21 are mainly expressed in immune related organs, such as spleen, head kidney and gills, while TLR18 transcripts are more abundant in muscle. In vitro stimulation of primary head kidney cells with type I IFN, IFNγ and IL-1β had no impact on TLR expression. Infectious salmon anaemia virus (ISAV) infection, in vivo, down-regulated TLR20a, TLR20b(s), TLR20d and TLR21 in infected salmon kidney tissue. In contrast, up-regulation of TLR19 and TLR20a expression was found in posterior kidney in rainbow trout with clinical proliferative kidney disease (PKD).
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK. Electronic address: r01pl11@abdn.ac.uk.
authors.forename: P T
authors.initials: PT
authors.lastname: Lee
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: J
authors.initials: J
authors.lastname: Zou
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: J W
authors.initials: JW
authors.lastname: Holland
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: S A M
authors.initials: SA
authors.lastname: Martin
authors.affiliation: Marine Scotland, 375 Victoria Road, Aberdeen AB11 9DB, UK.
authors.forename: B
authors.initials: B
authors.lastname: Collet
authors.affiliation: Zoetis International Service, 23-25 Avenue du Dr. Lannelongue 75668 Paris Cedex 14, France.
authors.forename: T
authors.initials: T
authors.lastname: Kanellos
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Secombes
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003001:Cloning, Molecular; D019295:Computational Biology; D005393:Fish Diseases / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology*; D023281:Genomics / Q000379:methods; D060226:Head Kidney / Q000166:cytology; D007674:Kidney Diseases / Q000378:metabolism / Q000662:veterinary*; D007962:Leukocytes / Q000378:metabolism; D018613:Microscopy, Confocal; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D020317:Salmo salar / Q000235:genetics* / Q000276:immunology; D013045:Species Specificity; D051193:Toll-Like Receptors / Q000235:genetics* / Q000378:metabolism
chemical_list: D051193:Toll-Like Receptors
keywords: Atlantic salmon; Gene expression; Innate immunity; TLR; Toll-like receptor