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TGF-beta signals and a pattern in Xenopus laevis endodermal development
G L Henry1, I H Brivanlou, D S Kessler
1Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Development (Cambridge, England)
|March 1, 1996
Summary
Early Xenopus endoderm development involves signaling pathways. TGF-beta signaling influences germ layer segregation and the expression of pancreas and intestinal markers.
Area of Science:
- Developmental Biology
- Xenopus laevis Embryogenesis
- Molecular Signaling Pathways
Background:
- Early endoderm development in Xenopus laevis involves the expression of specific gene products.
- Pancreas development is marked by Xlhbox-8, while intestinal fatty acid binding protein (IFABP) marks the small intestinal epithelium.
Purpose of the Study:
- To investigate the signaling mechanisms regulating gene expression in the early Xenopus endoderm.
- To determine the role of transforming growth factor-beta (TGF-beta) and fibroblast growth factor (FGF) signaling in endodermal patterning.
- To explore the relationship between endodermal patterning and mesodermal development signals.
Main Methods:
- Analysis of gene expression patterns for Xlhbox-8 and IFABP in early Xenopus endoderm.
- Utilized endodermal explants devoid of mesoderm.
- Investigated the role of cortical rotation and TGF-beta signaling inhibition.
Main Results:
- Pancreas marker (Xlhbox-8) expression depends on TGF-beta and FGF signaling.
- Small intestinal marker (IFABP) expression is independent of these signals.
- Cortical rotation is essential for anterior marker (Xlhbox-8) but not posterior marker (IFABP) expression.
- Inhibition of TGF-beta signaling leads to ectopic expression of mesodermal and ectodermal markers.
Conclusions:
- Endodermal patterning is influenced by signaling events crucial for mesodermal development.
- TGF-beta signaling plays a significant role in segregating the three embryonic germ layers in Xenopus.
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