ZFIN ID: ZDB-PUB-020115-3
Regulation of nodal signalling and mesendoderm formation by TARAM-A, a TGFbeta-related type I receptor
Aoki, T.O., Mathieu, J., Saint-Etienne, L., Rebagliati, M.R., PeyriƩras, N., and Rosa, F.M.
Date: 2002
Source: Developmental Biology   241(2): 273-288 (Journal)
Registered Authors: Mathieu, Juliette, Rebagliati, Michael, Rosa, Frederic, Saint-Etienne, Laure
Keywords: zebrafish; nodal; endoderm; signalling; dominant-negative
MeSH Terms:
  • Activins/metabolism
  • Animals
  • Biomarkers
  • Body Patterning/genetics
  • Body Patterning/physiology*
  • Bone Morphogenetic Proteins/physiology
  • Embryo, Nonmammalian/physiology
  • Endoderm/physiology*
  • Gene Expression Regulation, Developmental*
  • Genes, Dominant
  • Homeodomain Proteins/genetics
  • Homeodomain Proteins/physiology
  • Intracellular Signaling Peptides and Proteins
  • Mesoderm/physiology*
  • Mutagenesis
  • Nodal Protein
  • Nodal Signaling Ligands
  • Phenotype
  • Protein-Serine-Threonine Kinases*
  • Receptors, Transforming Growth Factor beta/genetics
  • Receptors, Transforming Growth Factor beta/physiology*
  • Recombinant Fusion Proteins/physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction/genetics
  • Signal Transduction/physiology*
  • Transcription Factors/genetics
  • Transcription Factors/physiology
  • Transforming Growth Factor beta/genetics
  • Transforming Growth Factor beta/physiology*
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish Proteins*
PubMed: 11784111 Full text @ Dev. Biol.
Nodal signalling is essential for many developmental events during vertebrate development, including the establishment of left-right asymmetry, of dorsoventral axis of the central nervous system, and endoderm and mesoderm formation. The zebrafish TGFbeta-related type I receptor, TARAM-A (Tar), is expressed in the prospective mesendodermal territory and, when activated, can transfate early blastomeres into endoderm, suggesting that Nodal and Tar may represent similar signalling pathways. We have analysed the functional relationships between those two pathways in zebrafish. We first demonstrate that tar and the zebrafish nodal genes cyc and sqt functionally interact. We also show that a dominant-negative isoform of Tar, TarMR, interferes specifically with the function of Cyc and Sqt in vitro, but does not interfere with the function of BMP2, another TGFbeta-related molecule. TarMR interferes also with Nodal signalling in vivo since it enhances the phenotyp! e of embryos with weakened Nodal signalling. Overexpression of tarMR in wild-type embryos interfered with the formation of endoderm-derived structures. Conversely, overexpression of tar enlarged the presumptive mesendodermal region at the onset of gastrulation. Together, our results point to Tar as an essential factor for endoderm formation and an important modulator of Nodal signalling, potentially representing one of the Nodal receptors.