title: Sequence and expression analysis of two T helper master transcription factors, T-bet and GATA3, in rainbow trout Oncorhynchus mykiss and analysis of their expression during bacterial and parasitic infection.
abstract: The polarization of naïve CD4+ T cells to T helper (Th)1 or Th2 cells is specified by two master transcription factors, T-bet and GATA3, and is an essential feature of mammalian adaptive immune responses to pathogens and the development of long-lasting immunity. We report here the cloning of rainbow trout Oncorhynchus mykiss T-bet and GATA3, to allow the future evaluation of the existence of Th1 and Th2 cells in salmonid fish. The trout T-bet translation shares high amino acid identities to other fish T-bet molecules (71-72%) but low identities to mammalian T-bet genes (41-42%), although the middle T-box DNA binding domain is highly conserved among all the T-bet proteins from fish and mammals. The trout GATA3 has high amino acid sequence identities (73-88%) to all known vertebrate molecules, with two highly conserved zinc finger motifs. The identity of the trout T-bet and GATA3 molecules was confirmed by phylogenetic tree analysis. A comparable expression level of T-bet and GATA3 was seen in the spleen, head kidney and muscle in healthy trout, but a higher expression level of GATA3 was seen in the gills, brain, skin and intestine relative to that of T-bet. T-bet and GATA3 expression was modulated by different stimulants. The T cell stimulant PHA up-regulated the expression of both T-bet and GATA3 in splenocytes, suggesting that they may be mainly expressed by activated T cells. The expression of T-bet and GATA3 in the spleen was increased by acute stress, but their expression was inhibited by bacterial (Yersinia ruckeri) infection. In a parasitic infection model, Tetracapsuloides bryosalmonae infection induced a biased gene expression profile where a large increase in the expression of T-bet, IFN-gamma and IL-2 was seen, suggesting that a Th1-like response is likely induced by this disease. A better understanding of pathogen modulated expression of T-bet and GATA3, and the potential underlying host immune responses elicited as a consequence of their expression, may allow novel future control measures against disease in fish to be developed.
authors.affiliation: Scottish Fish Immunology Research Centre, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: Tiehui
authors.initials: T
authors.lastname: Wang
authors.forename: Jason W
authors.initials: JW
authors.lastname: Holland
authors.forename: Sam A M
authors.initials: SA
authors.lastname: Martin
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
mesh_terms: D000818:Animals; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D050990:GATA3 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D055764:Myxozoa; D017686:Oncorhynchus mykiss; D010273:Parasitic Diseases, Animal / Q000235:genetics / Q000276:immunology*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013045:Species Specificity; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D015009:Yersinia Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary*; D044124:Yersinia ruckeri; D000098815:T-bet Transcription Factor
chemical_list: D017931:DNA Primers; D050990:GATA3 Transcription Factor; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor