Skip to main content
eScholarship
Open Access Publications from the University of California

Neural induction in the absence of organizer in salamanders is mediated by MAPK

  • Author(s): Hurtado, Cecilia
  • De Robertis, E M
  • et al.
Abstract

Research on the mechanisms of embryonic induction had a great setback in the 1940s when Barth discovered and Holtfreter confirmed that ectoderm of Ambystoma maculatum salamander embryos could form brain tissue when cultured in a simple saline solution. We have revisited this classical experiment and found that when cultured animal cap ectoderm attaches to a glass substratum, it can self-organize to form complex organs such as brain vesicles, eyes, lens and olfactory placodes. Only anterior neural organs were generated. Under these culture conditions ERK became diphosphorylated, indicating a sustained activation of the Ras/MAPK pathway. Using sand particles as an example of a heterologous neural inducer similar results were obtained. Addition of U0126, a specific antagonist of MEK, the enzyme that phosphorylates ERK/MAPK, inhibited neural differentiation. The closely related control compound U0124 had no effect. We conclude that neural induction in the absence of organizer in A. maculatum requires Ras/MAPK-activation. These findings provide a molecular explanation for the activity of heterologous neural inducers that dominated thinking in amphibian experimental embryology for many decades. (c) 2007 Elsevier Inc. All rights reserved.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View