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The maternal Xenopus β‐catenin signaling pathway, activated by frizzled homologs, induces goosecoid in a cell non‐autonomous manner
Author(s) -
Brown Jeffrey D.,
Hallagan Sarah E.,
McGrew L. Lynn,
Miller Jeffrey R.,
Moon Randall T.
Publication year - 2000
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.2000.00517.x
Subject(s) - xenopus , wnt signaling pathway , frizzled , microbiology and biotechnology , biology , lrp5 , lrp6 , homeobox , catenin , signal transduction , gene , beta catenin , gene expression , genetics
In spite of abundant evidence that Wnts play essential roles in embryonic induction and patterning, little is known about the expression or activities of Wnt receptors during embryogenesis. The isolation and expression of two maternal Xenopus frizzled genes, Xfrizzled ‐1 and Xfrizzled ‐7, is described. It is also demonstrated that both can activate the Wnt/β‐catenin signaling pathway as monitored by the induction of specific target genes. Activation of the β‐Catenin pathway has previously been shown to be necessary and sufficient for specifying the dorsal axis of Xenopus . β‐Catenin is thought to work through the cell‐autonomous induction of the homeobox genes siamois and twin , that in turn bind to and activate the promoter of another homeobox gene, goosecoid . However, it was found that the β‐catenin pathway regulated the expression of both endogenous goosecoid , and a goosecoid promoter construct, in a cell non‐autonomous manner. These data demonstrate that maternal Frizzleds can activate the Wnt/β‐catenin pathway in Xenopus embryos, and that induction of a known downstream gene can occur in a cell non‐autonomous manner.