Nodal signals mediate interactions between the extra-embryonic and embryonic tissues in zebrafish

Xiang Fan, Engda G. Hagos, Bo Xu, Christina Sias, Koichi Kawakami, Rebecca D. Burdine, Scott T. Dougan

Research output: Contribution to journalArticle

35 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)363-378
Number of pages16
JournalDevelopmental biology
Volume310
Issue number2
DOIs
StatePublished - Oct 15 2007

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

Keywords

  • EVL
  • Endoderm
  • Extra-embryonic
  • Mesoderm
  • Nodal-related
  • SB-505124
  • YSL
  • Zebrafish
  • cyclops
  • squint

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