Blocking Dishevelled signaling in the noncanonical Wnt pathway in sea urchins disrupts endoderm formation and spiculogenesis, but not secondary mesoderm formation.

Published

Journal Article

Dishevelled (Dsh) is a phosphoprotein key to beta-catenin dependent (canonical) and beta-catenin independent (noncanonical) Wnt signaling. Whereas canonical Wnt signaling has been intensively studied in sea urchin development, little is known about other Wnt pathways. To examine roles of these beta-catenin independent pathways in embryogenesis, we used Dsh-DEP, a deletion construct blocking planar cell polarity (PCP) and Wnt/Ca(2+) signaling. Embryos overexpressing Dsh-DEP failed to gastrulate or undergo skeletogenesis, but produced pigment cells. Although early mesodermal gene expression was largely unperturbed, embryos exhibited reduced expression of genes regulating endoderm specification and differentiation. Overexpressing activated beta-catenin failed to rescue Dsh-DEP embryos, indicating that Dsh-DEP blocks endoderm formation downstream of initial canonical Wnt signaling. Because Dsh-DEP-like constructs block PCP signaling in other metazoans, and disrupting RhoA or Fz 5/8 in echinoids blocks subsets of the Dsh-DEP phenotypes, our data suggest that noncanonical Wnt signaling is crucial for sea urchin endoderm formation and skeletogenesis.

Full Text

Duke Authors

Cited Authors

  • Byrum, CA; Xu, R; Bince, JM; McClay, DR; Wikramanayake, AH

Published Date

  • July 2009

Published In

Volume / Issue

  • 238 / 7

Start / End Page

  • 1649 - 1665

PubMed ID

  • 19449300

Pubmed Central ID

  • 19449300

Electronic International Standard Serial Number (EISSN)

  • 1097-0177

International Standard Serial Number (ISSN)

  • 1058-8388

Digital Object Identifier (DOI)

  • 10.1002/dvdy.21978

Language

  • eng