p38 MAPK is essential for secondary axis specification and patterning in sea urchin embryos.

Published

Journal Article

Most eggs in the animal kingdom establish a primary, animal-vegetal axis maternally, and specify the remaining two axes during development. In sea urchin embryos, the expression of Nodal on the oral (ventral) side of the embryo is the first known molecular determinant of the oral-aboral axis (the embryonic dorsoventral axis), and is crucial for specification of the oral territory. We show that p38 MAPK acts upstream of Nodal and is required for Nodal expression in the oral territory. p38 is uniformly activated early in development, but, for a short interval at late blastula stage, is asymmetrically inactivated in future aboral nuclei. Experiments show that this transient asymmetry of p38 activation corresponds temporally to both oral specification and the onset of oral Nodal expression. Uniform inhibition of p38 prevents Nodal expression and axis specification, resulting in aboralized embryos. Nodal and its target Gsc each rescue oral-aboral specification and patterning when expressed asymmetrically in p38-inhibited embryos. Thus, our results indicate that p38 is required for oral specification through its promotion of Nodal expression in the oral territory.

Full Text

Duke Authors

Cited Authors

  • Bradham, CA; McClay, DR

Published Date

  • January 2006

Published In

Volume / Issue

  • 133 / 1

Start / End Page

  • 21 - 32

PubMed ID

  • 16319119

Pubmed Central ID

  • 16319119

Electronic International Standard Serial Number (EISSN)

  • 1477-9129

International Standard Serial Number (ISSN)

  • 0950-1991

Digital Object Identifier (DOI)

  • 10.1242/dev.02160

Language

  • eng