PUBLICATION

Transforming growth factor-β1b: A second TGF-β1 paralogue in the rainbow trout (Oncorhynchus mykiss) that has a lower constitutive expression but is more responsive to immune stimulation

Authors
Maehr, T., Costa, M.M., González Vecino, J.L., Wadsworth, S., Martin, S., Wang, T., and Secombes, C.J.
ID
ZDB-PUB-121205-51
Date
2013
Source
Fish & shellfish immunology   34(2): 420-432 (Journal)
Registered Authors
Keywords
rainbow trout, TGF-β, macrophage, LPS, poly(I:C), VHSV, gene expression
MeSH Terms
  • Animals
  • Base Sequence
  • Cytokines/pharmacology
  • Fish Diseases/immunology*
  • Fish Diseases/virology*
  • Gene Components
  • Gene Expression Profiling/veterinary
  • Gene Expression Regulation, Developmental/drug effects
  • Gene Expression Regulation, Developmental/immunology*
  • Head Kidney/metabolism
  • Lipopolysaccharides/pharmacology
  • Mitogens/pharmacology
  • Molecular Sequence Data
  • Novirhabdovirus*
  • Oncorhynchus mykiss/genetics*
  • Oncorhynchus mykiss/immunology
  • Poly I-C/pharmacology
  • Rhabdoviridae Infections/immunology
  • Rhabdoviridae Infections/veterinary*
  • Sequence Analysis, DNA/veterinary
  • Species Specificity
  • Transforming Growth Factor beta1/genetics*
  • Transforming Growth Factor beta1/immunology
  • Transforming Growth Factor beta1/metabolism
PubMed
23178261 Full text @ Fish Shellfish Immunol.
Abstract

The rainbow trout (Oncorhynchus mykiss) TGF-β1 sequence was one of the first fish cytokines described. Studies of its expression suggest it is constitutively expressed but displays refractory inducibility. Here we describe a second TGF-β1 (TGF-β1b) gene that is novel in several respects. TGF-β1b possesses typical TGF-β features, including a CXC motif and an integrin binding site, a tetrabasic cut site and a mature peptide of 112 amino acids (aa) containing nine conserved cysteine residues. The mature peptide is 83% identical to the first TGF-β1 sequence described in rainbow trout, that we designate TGF-β1a, and relative to TGF-β1a shows higher homology to Atlantic salmon TGF-β1b, zebrafish TGF-β1a, and sea bass, and seabream TGF-β1. The gene organisation of salmonid TGF-β1b genes, as inferred from Atlantic salmon whole genome shotgun contigs, is a 6 exon/5 intron structure with exons 3 and 4 of salmonid TGF-β1a genes apparently fused together. The two trout TGF-β1 genes have a wide distribution in vivo, with highest expression found in immune tissues for both isoforms indicating that TGF-β1 has a predominant role in immunity of fish. Expression of both genes was also seen during the ontogeny of trout, with TGF-β1a relatively constant in expression level but TGF-β1b increasing over time. Immune responses in head kidney (HK) macrophages induced by pathogen associated molecular patterns (PAMPs), pro-inflammatory cytokines, mitogens and pathway activators highly elevated the expression level of TGF-β1b but not that of TGF-β1a. TGF-β1b expression was also increased by polyinosinic:polycytidylic acid (poly(I:C)) and/or lipopolysaccharide (LPS) stimulation in three different trout cell lines studied. Finally we show that TGF-β1b is potentially involved in defense against infection with viral haemorrhagic septicemia virus (VHSV), which had no effect on TGF-β1a expression. Thus, it is likely the TGF-β1b gene represents a copy which fulfils the major immune orchestrating functions of TGF-β1 as seen in other vertebrates.

Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping