Early anteroposterior division of the presumptive neurectoderm in Xenopus.
We analyze the timing of neural patterning in Xenopus and the mechanism by which the early pattern is generated. With regard to timing, we show that by early gastrula, two domains of the anteroposterior (A/P) pattern exist in the presumptive neurectoderm, since the opl gene is expressed throughout the future neural plate, while the fkh5 gene is expressed only in more posterior ectoderm. By mid-gastrula, this pattern has become more elaborate, with an anterior domain defined by expression of opl and otx2, a middle domain defined by expression of opl and fkh5, and a posterior domain defined by expression of opl, fkh5 and HoxD1. Explant assays indicate that the late blastula dorsal ectoderm is specified as the anterior domain, but is not yet specified as middle or posterior domains. With regard to the mechanism by which the A/P pattern is generated, gain and loss of function assays indicate that quantitatively and qualitatively different factors may be involved in inducing the early A/P neural pattern. These data show that neural patterning occurs early in Xenopus and suggest a molecular basis for initiating this pattern.
Gamse
J T
JT
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
Sive
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D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins; D002455:Cell Division; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004475:Ectoderm / Q000378:metabolism / Q000502:physiology*; D005346:Fibroblast Growth Factors / Q000378:metabolism; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins; D017403:In Situ Hybridization; D008957:Models, Genetic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009420:Nervous System / Q000196:embryology*; D009474:Neurons / Q000378:metabolism; D051857:Otx Transcription Factors; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D014981:Xenopus; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology*; D000099176:Noggin Protein
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D005346:Fibroblast Growth Factors; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; D011506:Proteins; D012313:RNA; D015534:Trans-Activators; D014157:Transcription Factors; D029867:Xenopus Proteins; D000099176:Noggin Protein; C491331:FOXB1 protein, Xenopus; C497661:Otx2 protein, Xenopus; C116546:Zic1 protein, Xenopus