Functional characterisation of a TLR accessory protein, UNC93B1, in Atlantic salmon (Salmo salar)

P. T. Lee, J. Zou, J. W. Holland, S. A. M. Martin, C. J. W. Scott, T. Kanellos, C. J. Secombes*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)



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 vitroin 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.

Original languageEnglish
Pages (from-to)38-48
Number of pages11
JournalDevelopmental and Comparative Immunology
Issue number1
Early online date7 Jan 2015
Publication statusPublished - May 2015

Bibliographical note

Copyright © 2014 Elsevier Ltd. All rights reserved.
L.P.-T. was supported by a PhD studentship from the Ministry of Education, Republic of China (Taiwan). This work was also funded by the European Community's seventh framework programme (FP7/2007–2013) under grant agreement no. 222719 (LIFECYCLE). The authors gratefully acknowledge Lucy Wight from the Microscopy and Histology Core Facility at the University of Aberdeen for help with the confocal microscopy.


  • Accessory protein
  • Atlantic salmon
  • Gene expression
  • Innate immunity
  • TLR
  • UNC93B1


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