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ZIRC
ZFIN ID: ZDB-PUB-070920-8
Nodal signals mediate interactions between the extra-embryonic and embryonic tissues in zebrafish
Fan, X., Hagos, E.G., Xu, B., Sias, C., Kawakami, K., Burdine, R.D., and Dougan, S.T.
Date: 2007
Source: Developmental Biology 310(2): 363-378 (Journal)
Registered Authors: Burdine, Rebecca, Dougan, Scott T., Fan, Xiang, Hagos, Engda, Kawakami, Koichi, Xu, Bo
Keywords: Zebrafish, squint, cyclops, EVL, YSL, Nodal-related, Mesoderm, Endoderm, Extra-embryonic, SB-505124
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Body Patterning
  • Endoderm/metabolism
  • Gene Expression Regulation, Developmental
  • Intracellular Signaling Peptides and Proteins/genetics
  • Intracellular Signaling Peptides and Proteins/metabolism*
  • Mesoderm/metabolism
  • Molecular Sequence Data
  • Nodal Signaling Ligands
  • Response Elements
  • Signal Transduction
  • Zebrafish/embryology
  • Zebrafish/physiology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 17850782 Full text @ Dev. Biol.
FIGURES
ABSTRACT
In many vertebrates, extra-embryonic tissues are important signaling centers that induce and pattern the germ layers. In teleosts, the mechanism by which the extra-embryonic yolk syncytial layer (YSL) patterns the embryo is not understood. Although the Nodal-related protein Squint is expressed in the YSL, its role in this tissue is not known. We generated a series of stable transgenic lines with GFP under the control of squint genomic sequences. In all species, nodal-related genes induce their own expression through a positive feedback loop. We show that two tissue specific enhancers in the zebrafish squint gene mediate the response to Nodal signals. Expression in the blastomeres depends upon a conserved Nodal response element (NRE) in the squint first intron, while expression in the extra-embryonic enveloping layer (EVL) is mediated by an element upstream of the transcription start site. Targeted depletion experiments demonstrate that the zebrafish Nodal-related proteins Squint and Cyclops are required in the YSL for endoderm and head mesoderm formation. Thus, Nodal signals mediate interactions between embryonic and extra-embryonic tissues in zebrafish that maintain nodal-related gene expression in the margin. Our results demonstrate a high degree of functional conservation between the extra-embryonic tissues of mouse and zebrafish.
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