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Integrin-dependent adhesive activity is spatially controlled by inductive signals at gastrulation
J W Ramos1, C A Whittaker, D W DeSimone
1Department of Cell Biology, University of Virginia, Charlottesville 22908, USA.
Development (Cambridge, England)
|September 1, 1996
Summary
Integrin cell adhesion to fibronectin is crucial for embryonic development. Inductive signals during gastrulation regulate this process, controlling cell migration and tissue formation in Xenopus embryos.
Area of Science:
- Developmental Biology
- Cell Biology
- Biochemistry
Background:
- Integrins are key mediators of cell-extracellular matrix (ECM) interactions, vital for embryonic morphogenesis.
- Regulation of integrin adhesive activity during early embryonic development remains largely uncharacterized.
Purpose of the Study:
- To investigate the regulation of integrin-dependent cell adhesion during Xenopus gastrulation.
- To identify the role of specific fibronectin binding domains and integrin subunits in developmental processes.
Main Methods:
- Utilized Xenopus laevis embryo explants (animal caps) and in vitro cell adhesion assays.
- Investigated fibronectin binding to Arg-Gly-Asp (RGD) and V-region domains.
- Examined the effects of activin-A treatment and ectopic integrin alpha4beta1 expression.
Main Results:
- Integrin-dependent cell adhesion to fibronectin's RGD domain is essential for gastrulation in Xenopus.
- Only involuting cells exhibit spreading and migration on fibronectin, a change mimicked by activin-A treatment in animal cap cells.
- Activin-induced adhesion changes are independent of transcription, translation, or receptor expression levels.
Conclusions:
- Cell adhesion to fibronectin is dynamically regulated in space and time during Xenopus development, controlled by gastrulation-initiating signals.
- Integrin alpha4beta1 mediates adhesion to fibronectin's V-region, and its function is modulated by activin signaling.
- Position-specific inductive interactions represent a novel mechanism for modulating integrin adhesion during development.