title: Antagonistic regulation of convergent extension movements in Xenopus by Wnt/beta-catenin and Wnt/Ca2+ signaling.
abstract: Convergent extension movements are the main driving force of Xenopus gastrulation. A fine-tuned regulation of cadherin-mediated cell-cell adhesion is thought to be required for this process. Members of the Wnt family of extracellular glycoproteins have been shown to modulate cadherin-mediated cell-cell adhesion, convergent extension movements, and cell differentiation. Here we show that endogenous Wnt/beta-catenin signaling activity is essential for convergent extension movements due to its effect on gene expression rather than on cadherins. Our data also suggest that XLEF-1 rather than XTCF-3 is required for convergent extension movements and that XLEF-1 functions in this context in the Wnt/beta-catenin pathway to regulate Xnr-3. In contrast, activation of the Wnt/Ca2+ pathway blocks convergent extension movements, with potential regulation of the Wnt/beta-catenin pathway at two different levels. PKC, activated by the Wnt/Ca2+ pathway, blocks the Wnt/beta-catenin pathway upstream of beta-catenin and phosphorylates Dishevelled. CamKII, also activated by the Wnt/Ca2+ pathway, inhibits the Wnt/beta-catenin signaling cascade downstream of beta-catenin. Thus, an opposing cross-talk of two distinct Wnt signaling cascades regulates convergent extension movements in Xenopus.
authors.affiliation: Abteilung Entwicklungsbiochemie, Junior Group SFB 271, Universität Göttingen, Humboldtallee 23, D-37073, Göttingen, Germany. mkuehl@gwdg.de
authors.forename: M
authors.initials: M
authors.lastname: Kühl
authors.forename: K
authors.initials: K
authors.lastname: Geis
authors.forename: L C
authors.initials: LC
authors.lastname: Sheldahl
authors.forename: T
authors.initials: T
authors.lastname: Pukrop
authors.forename: R T
authors.initials: RT
authors.lastname: Moon
authors.forename: D
authors.initials: D
authors.lastname: Wedlich
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002465:Cell Movement; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000502:physiology*; D005775:Gastrula / Q000166:cytology / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D051821:Lymphoid Enhancer-Binding Factor 1; D011493:Protein Kinase C / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D014981:Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: C495266:CTNNB1 protein, Xenopus; D003598:Cytoskeletal Proteins; D006609:High Mobility Group Proteins; C116548:Lef1 protein, Xenopus; D051821:Lymphoid Enhancer-Binding Factor 1; D011506:Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C085096:Wnt5a protein, Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; C094620:nodal3.1 protein, Xenopus; D011493:Protein Kinase C; D002118:Calcium