Xenopus cadherin-11 (Xcadherin-11) expression requires the Wg/Wnt signal

In this study we describe the isolation of Xcadherin-11, the Xenopus homologue to the mesenchymal cadherin-11. Similar to epithelial and neural cadherins, overexpression of Xcadherin-11 led to posteriorised phenotypes due to inhibition of convergent extension movement. Because zygotic expression of Xcadherin-11 starts with gastrulation, we analysed the ability of different growth factors involved in mesoderm differentiation to induce the expression of Xcadherin-11. Using the animal cap assay, we demonstrated that Xcadherin-11 is activated by Xwnt-8 or beta-catenin, but repressed by BMP-4. Activin did not induce Xcadherin-11 but its synergistic function was required for the Xwnt-8/beta-catenin-mediated activation of Xcadherin-11. Because Xcadherin-11 and Xenopus E- and N-cadherin are differentially regulated by growth factors in the Xenopus animal cap, our results also reveal that this assay provides a helpful model system to elucidate the molecular control mechanism of epithelial-mesenchymal conversion.