Lineage/species-specific expansion of the Mx gene family in teleosts: Differential expression and modulation of nine Mx genes in rainbow trout Oncorhynchus mykiss

Tingyu Wang, Fuguo Liu, Guangming Tian, Christopher J. Secombes (Corresponding Author), Tiehui Wang (Corresponding Author)

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Myxovirus resistance (Mx) proteins are interferon (IFN)-inducible Dynamin-like GTPases, which play an important role in antiviral immunity. Three Mx genes (Mx1-3) have been cloned previously in rainbow trout. In this study, an additional six Mx genes were cloned that reside in four chromosomal loci. Further bioinformatics analysis suggests the presence of three teleost Mx groups (TMG) each with a characteristic gene organisation. Salmonid Mx belong to TMG1 and TMG2. The increased salmonid Mx gene copies are due mainly to local gene duplications that happened before and after salmonid speciation, in a lineage/species specific manner. Trout Mx molecules have been diversified in the loop 1 and 4 regions, and in the nuclear localisation signal in loop 4. The trout Mx genes were shown to be differentially expressed in tissues, with high levels of expression of TMG1 (Mx1-4) in blood and TMG2 (Mx5-9) in intestine. The expression of the majority of the trout Mx genes was induced by poly IC in vitro and in vivo, and increased during development. In addition, induction by antiviral (IFN) and proinflammatory cytokines was studied, and showed that type I IFN, IFNγ and IL-1β can induce Mx gene expression in an Mx gene-, cytokine- and cell line-dependent manner. These results show that salmonids possess a large number Mx genes as well as complex regulatory pathways, which may contribute to their success in an anadromous life style.
Original languageEnglish
Pages (from-to)413-430
Number of pages18
JournalFish & Shellfish Immunology
Volume90
Early online date4 May 2019
DOIs
Publication statusPublished - 1 Jul 2019

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Keywords

  • Rainbow trout
  • Mx
  • Anti-viral defence
  • Evolution
  • Gene expression
  • Modulation
  • Type I interferon
  • IFNγ
  • IL-1β

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