Caudal-related Homeobox (Cdx) Protein-Dependent Integration of Canonical Wnt Signaling on Paired-Box 3 (Pax3) Neural Crest Enhancer

J Biol Chem. 2012 May 11;287(20):16623-35. doi: 10.1074/jbc.M112.356394. Epub 2012 Mar 28.

Abstract

One of the earliest events in neural crest development takes place at the neural plate border and consists in the induction of Pax3 expression by posteriorizing Wnt·β-catenin signaling. The molecular mechanism of this regulation is not well understood, but several observations suggest a role for posteriorizing Cdx transcription factors (Cdx1/2/4) in this process. Cdx genes are known as integrators of posteriorizing signals from Wnt, retinoic acid, and FGF pathways. In this work, we report that Wnt-mediated regulation of murine Pax3 expression is indirect and involves Cdx proteins as intermediates. We show that Pax3 transcripts co-localize with Cdx proteins in the posterior neurectoderm and that neural Pax3 expression is reduced in Cdx1-null embryos. Using Wnt3a-treated P19 cells and neural crest-derived Neuro2a cells, we demonstrate that Pax3 expression is induced by the Wnt-Cdx pathway. Co-transfection analyses, electrophoretic mobility shift assays, chromatin immunoprecipitation, and transgenic studies further indicate that Cdx proteins operate via direct binding to an evolutionarily conserved neural crest enhancer of the Pax3 proximal promoter. Taken together, these results suggest a novel neural function for Cdx proteins within the gene regulatory network controlling neural crest development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CDX2 Transcription Factor
  • Enhancer Elements, Genetic / physiology*
  • Epidermal Growth Factor / genetics
  • Epidermal Growth Factor / metabolism
  • Gene Expression Regulation, Developmental / physiology
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Neural Crest / embryology*
  • PAX3 Transcription Factor
  • Paired Box Transcription Factors / genetics
  • Paired Box Transcription Factors / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Wnt Signaling Pathway / physiology*

Substances

  • CDX2 Transcription Factor
  • Cdx1 protein, mouse
  • Cdx2 protein, mouse
  • Cdx4 protein, mouse
  • Homeodomain Proteins
  • PAX3 Transcription Factor
  • Paired Box Transcription Factors
  • Transcription Factors
  • Pax3 protein, mouse
  • Epidermal Growth Factor