Multiple roles for Nodal in the epiblast of the mouse embryo in the establishment of anterior-posterior patterning.
The TGFbeta family member Nodal has been shown to be involved in a variety of processes in development, including early axis formation. Here, we use a conditional gene inactivation strategy to show a specific requirement for Nodal in the epiblast. Complete inactivation of the Nodal locus in the epiblast using the Sox2-Cre deleter strain results in a failure to establish global anterior-posterior patterning, a phenotype that resembles the Nodal null phenotype. By contrast, mosaic inactivation of Nodal in the epiblast using the Mox2-Cre (MORE) deleter strain affects formation of the anterior mesendoderm and subsequent anterior neurectoderm patterning. Furthermore, ES cell chimera experiments indicate that Nodal-deficient ES cells preferentially populate the anterior compartment of the epiblast, suggesting that cell mixing in the epiblast is not random and that Nodal signaling mediates a novel anterior-posterior cell-sorting process within the epiblast before gastrulation.
Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Cindy C
CC
Lu
Elizabeth J
EJ
Robertson
D000483:Alleles; D000818:Animals; D015139:Blotting, Southern; D019521:Body Patterning / Q000502:physiology*; D004475:Ectoderm / Q000378:metabolism / Q000502:physiology; D004707:Endoderm / Q000378:metabolism / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology*; D017403:In Situ Hybridization; D051379:Mice / Q000196:embryology*; D055457:Nodal Protein; D010641:Phenotype; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D055457:Nodal Protein; C526008:Nodal protein, mouse; D016212:Transforming Growth Factor beta