Apolipoprotein C-I mediates Wnt/Ctnnb1 signaling during neural border formation and is required for neural crest development

Int J Dev Biol. 2017;61(6-7):415-425. doi: 10.1387/ijdb.160399cy.

Abstract

In vertebrates, the neural crest and placodes originate in the neural border, which is located between the neural plate and epidermal ectoderm. The neural crest and placodes give rise to a vast array of cell types. Formation of neural crest is a multi-step process, in which Wnt signals are used reiteratively, but it is currently not clear if a Wnt signal is required for neural border formation. Here, we have identified apolipoprotein C-I (apoc1) in a screen for genes regulated by Wnt/Ctnnb1 signaling in late blastula stage Xenopus tropicalis embryos. We show that Xenopus laevis apoc1 encodes a small, secreted protein, and is induced by Wnt/Ctnnb1 signaling. Depletion of Apoc1 protein results in a neural border formation defect and loss of border fates, including neural crest cells. However, unlike another Wnt/Ctnnb1 target, gbx2.2, apoc1 is not required for patterning of the neural border. We further show that gbx2.2 and apoc1 are independently regulated by Wnt signaling. Our results thus suggest that Wnt regulates border formation and patterning by distinct genetic mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apolipoprotein C-I / genetics
  • Apolipoprotein C-I / metabolism*
  • Body Patterning
  • Bone Morphogenetic Proteins / genetics
  • Bone Morphogenetic Proteins / metabolism
  • Cell Lineage
  • Embryo, Nonmammalian / cytology*
  • Embryo, Nonmammalian / metabolism
  • Female
  • Gene Expression Regulation, Developmental
  • Neural Crest / cytology*
  • Neural Crest / metabolism
  • Neurogenesis / physiology*
  • Signal Transduction
  • Wnt Proteins / genetics
  • Wnt Proteins / metabolism*
  • Xenopus Proteins / genetics
  • Xenopus Proteins / metabolism
  • Xenopus laevis / genetics
  • Xenopus laevis / growth & development*
  • Xenopus laevis / metabolism
  • beta Catenin / genetics
  • beta Catenin / metabolism*

Substances

  • Apolipoprotein C-I
  • Bone Morphogenetic Proteins
  • Wnt Proteins
  • Xenopus Proteins
  • beta Catenin