XENOPUS CADHERIN-11 (XCADHERIN-11) EXPRESSION REQUIRES THE WG WNT SIGNAL/

In this study we describe the isolation of Xcadherin-11: the Xenopus h omologue to the mesenchymal cadherin-ll. Similar to epithelial and neu ral cadherins, overexpression of Xcadherin-11 led to posteriorised phe notypes due to inhibition of convergent extension movement. Because zy gotic expression of Xcadherin-11 starts with gastrulation, we analysed the ability of different growth factors involved in mesoderm differen tiation to induce the expression of Xcadherin-11 Using the animal cap assay, we demonstrated that Xcadherin-11 is activated by Xwnt-8 or bet a-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 an 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. (C) 1998 Elsevier Science Ireland L td.