Galphaq negatively regulates the Wnt-beta-catenin pathway and dorsal embryonic Xenopus laevis development

• Published in: Journal of cellular physiology Vol. 214; no. 2; pp. 483 - 490
• Main Authors: Soto, Ximena, Mayor, Roberto, Torrejón, Marcela, Montecino, Martín, Hinrichs, María Victoria, Olate, Juan
• Format: Journal Article
• Language: English
• Published: United States 01-02-2008
• Subjects: Animals; beta Catenin - antagonists & inhibitors; Body Patterning; Embryo, Nonmammalian - metabolism; Embryonic Development; Gastrulation; Gene Expression Regulation, Developmental; GTP-Binding Protein alpha Subunits, Gq-G11 - metabolism; Wnt Proteins - antagonists & inhibitors; Xenopus laevis - embryology; Xenopus laevis - metabolism
• ISSN: 1097-4652

The non-canonical Wnt/Ca2+ signaling pathway has been implicated in the regulation of axis formation and gastrulation movements during early Xenopus laevis embryo development, by antagonizing the canonical Wnt/beta-catenin dorsalizing pathway and specifying ventral cell fate. However, the molecular mechanisms involved in this antagonist crosstalk are not known. Since Galphaq is the main regulator of Ca2+ signaling in vertebrates and from this perspective probably involved in the events elicited by the non-canonical Wnt/Ca2+ pathway, we decided to study the effect of wild-type Xenopus Gq (xGalphaq) in dorso-ventral axis embryo patterning. Overexpression of xGalphaq or its endogenous activation at the dorsal animal region of Xenopus embryo both induced a strong ventralized phenotype and inhibited the expression of dorsal-specific mesoderm markers goosecoid and chordin. Dorsal expression of an xGalphaq dominant-negative mutant reverted the xGalphaq-induced ventralized phenotype. Finally, we observed that the Wnt8-induced secondary axis formation is reverted by endogenous xGalphaq activation, indicating that it is negatively regulating the Wnt/beta-catenin pathway.