title: Functional characterisation of a TLR accessory protein, UNC93B1, in Atlantic salmon (Salmo salar).
abstract: Toll-like receptors (TLRs) are indispensable components of the innate immune system, which recognise conserved pathogen associated molecular patterns (PAMPs) and induce a series of defensive immune responses to protect the host. Biosynthesis, localisation and activation of TLRs are dependent on TLR accessory proteins. In this study, we identified the accessory protein, UNC93B1, from Atlantic salmon (Salmo salar) whole-genome shotgun (WGS) contigs aided by the conserved gene synteny of genes flanking UNC93B1 in fish, birds and mammals. Phylogenetic analysis showed that salmon UNC93B1 grouped with other vertebrate UNC93B1 molecules, and had highest amino acid identity and similarity to zebrafish UNC93B1. The salmon UNC93B1 gene organisation was also similar in structure to mammalian UNC93B1. Our gene expression studies revealed that salmon UNC93B1 was more highly expressed in spleen, liver and gill tissues but was expressed at a lower level in head kidney tissue in post-smolts relative to parr. Moreover, salmon UNC93B1 mRNA transcripts were up-regulated in vivo in spleen tissue from polyI:C treated salmon and in vitro in polyI:C or IFNγ stimulated Salmon Head Kidney-1 (SHK-1) cells. Initial studies into the functional role of salmon UNC93B1 in fish TLR signalling found that both wild type salmon UNC93B1 and a molecule with a site-directed mutation (H424R) co-immunoprecipitated with salmon TLR19, TLR20a and TLR20d. Overall, these data illustrate the potential importance of UNC93B1 as an accessory protein in fish TLR signalling.
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, United Kingdom.
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, United Kingdom.
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, United Kingdom.
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, United Kingdom.
authors.forename: S A M
authors.initials: SA
authors.lastname: Martin
authors.affiliation: Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, United Kingdom.
authors.forename: C J W
authors.initials: CJ
authors.lastname: Scott
authors.affiliation: Animal Health Division, Zoetis, 23-25 avenue du Dr. Lannelongue, Paris Cedex 14 75668, 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, United Kingdom. Electronic address: c.secombes@abdn.ac.uk.
authors.forename: C J
authors.initials: CJ
authors.lastname: Secombes
mesh_terms: D000818:Animals; D029941:Fish Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D010802:Phylogeny; D020317:Salmo salar / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000378:metabolism*
chemical_list: D029941:Fish Proteins; D026901:Membrane Transport Proteins; D051193:Toll-Like Receptors
keywords: Accessory protein; Atlantic salmon; Gene expression; Innate immunity; TLR; UNC93B1