Dorsalization of the neural tube by the non-neural ectoderm.
The patterning of cell types along the dorsoventral axis of the spinal cord requires a complex set of inductive signals. While the chordamesoderm is a well-known source of ventralizing signals, relatively little is known about the cues that induce dorsal cell types, including neural crest. Here, we demonstrate that juxtaposition of the non-neural and neural ectoderm is sufficient to induce the expression of dorsal markers, Wnt-1, Wnt-3a and Slug, as well as the formation of neural crest cells. In addition, the competence of neural plate to express Wnt-1 and Wnt-3a appears to be stage dependent, occurring only when neural tissue is taken from stage 8-10 embryos but not from stage 4 embryos, regardless of the age of the non-neural ectoderm. In contrast to the induction of Wnt gene expression, neural crest cell formation and Slug expression can be induced when either stage 4 or stage 8-10 neural plates are placed in contact with the non-neural ectoderm. These data suggest that the non-neural ectoderm provides a signal (or signals) that specifies dorsal cell types within the neural tube, and that the response is dependent on the competence of the neural tissue.
Dickinson
M E
ME
Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Selleck
M A
MA
McMahon
A P
AP
Bronner-Fraser
M
M
D000818:Animals; D002490:Central Nervous System / Q000196:embryology*; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology / Q000502:physiology*; D004627:Embryonic Induction / Q000235:genetics; D015870:Gene Expression; D017403:In Situ Hybridization; D009024:Morphogenesis / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics; D051153:Wnt Proteins; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D029961:Zebrafish Proteins; D016335:Zinc Fingers / Q000235:genetics
D011506:Proteins; D011518:Proto-Oncogene Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D051153:Wnt Proteins; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D029961:Zebrafish Proteins; D011505:Protein-Tyrosine Kinases