Signals from the dorsal blastopore lip region during gastrulation bias the ectoderm toward a nonepidermal pathway of differentiation in Xenopus laevis.
Epi 1, a monoclonal antibody, was generated against an epidermal specific epithelial antigen; it does not stain neural epithelium. We have used Epi 1 as a marker to determine when the spatial patterns delineating neural from nonneural epithelium become established. We used ventral ectoderm in a sandwich assay to show that signals from the central blastopore lip region, passing through the plane of the ectoderm sheet, define the pattern and boundary characteristics of Epi 1 expression. The dorsal blastopore lip at stages 10 and 12 are the strongest in inhibiting Epi 1 expression. The involuted chordamesoderm has only a limited inhibitory effect on Epi 1 expression in ventral ectoderm recombinates and does not appear to establish pattern boundaries. We suggest that the blastopore lip region establishes a preneural bias in the adjacent ectoderm prior to the interaction of the latter with chordamesoderm.
Savage
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Biology Department, Bowdoin College, Brunswick, Maine 04011.
Phillips
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D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D002454:Cell Differentiation; D046508:Culture Techniques; D004475:Ectoderm / Q000166:cytology*; D004707:Endoderm / Q000166:cytology / Q000502:physiology; D000078404:Epidermal Cells; D004848:Epithelium / Q000276:immunology; D005455:Fluorescent Antibody Technique; D005775:Gastrula / Q000502:physiology* / Q000637:transplantation; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D010614:Pharynx / Q000196:embryology; D014982:Xenopus laevis / Q000196:embryology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface