HEASMAN , Janet *; TAO, Qinghua ; YOKOTA, Chika ; KOFRON , Matt; LIN, Xinhua ; 1Division of Developmental Biology, Cincinnati Children�s Research Foundation: The canonical Wnt pathway and axis formation in Xenopus laevis

The establishment of the dorso-ventral and anterior posterior axes in Xenopus embryos has long been known to depend on a canonical Wnt signaling pathway, since beta catenin-depleted embryos lack axes. However the mechanism of activation of the pathway is controversial, and has generally been considered to occur intracellularly. We have shown recently that the canonical pathway is dependent on maternally localized Wnt11, and has all the characteristics of a regular, ligand-activated canonical Wnt pathway. Further confirmation of this will be presented, specifically that the pathway also depends on the Wnt co-receptor LRP6. The potential conservation of this patterning mechanism among other vertebrate groups will be discussed.