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Updated: Aug 19, 2026

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis
Published on: May 24, 2010
Regulation of Xenopus embryonic cell adhesion by the small GTPase, rac
Mark D Hens1, Ivana Nikolic, Caron M Woolcock
1Department of Biology, University of North Carolina at Greensboro, P.O. Box 26170, Greensboro, NC 27402-6170, USA. mdhens@uncg.edu
Abstract:
TGF-beta family signalling pathways are important for germ layer formation and gastrulation in vertebrate embryos and have been studied extensively using embryos of Xenopus laevis. Activin causes changes in cell movements and cell adhesion in Xenopus animal caps and dispersed animal cap cells. Rho family GTPases, including rac, mediate growth factor-induced changes in the actin cytoskeleton, and consequently, in cell adhesion and motility, in a number of different cell types. Ectopic expression of mutant rac isoforms in Xenopus embryos was combined with animal cap adhesion assays and a biochemical assay for rac activity to investigate the role of rac in activin-induced changes in cell adhesion. The results indicate that (1) the perturbation of rac signalling disrupts embryonic cell-cell adhesion, (2) that rac activity is required for activin-induced changes in cell adhesive behavior on fibronectin, and (3) that activin increases endogenous rac activity in animal cap explants.
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