Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-13009
Mech Dev 1999 Mar 01;811-2:65-74.
Show Gene links Show Anatomy links

The C-terminal transactivation domain of beta-catenin is necessary and sufficient for signaling by the LEF-1/beta-catenin complex in Xenopus laevis.



???displayArticle.abstract???
Beta-catenin is a multifunctional protein involved in cell adhesion and communication. In response to signaling by Wnt growth factors, beta-catenin associates with nuclear TCF factors to activate target genes. A transactivation domain identified at the C-terminus of beta-catenin can stimulate expression of artificial reporter genes. However, the mechanism of target gene activation by TCF/beta-catenin complexes and the physiological relevance of the beta-catenin transactivation domain still remain unclear. Here we asked whether the beta-catenin transactivation domain can generate a Wnt-response in a complex biological system, namely axis formation during Xenopus laevis embryogenesis. We show that a chimeric transcription factor consisting of beta-catenin fused to the DNA-binding domain of LEF-1 induces a complete secondary dorsoanterior axis when expressed in Xenopus. A LEF-1-beta-catenin fusion lacking the C-terminal transactivation domain is impaired in signaling while fusion of just the beta-catenin transactivator to the DNA-binding domain of LEF-1 is sufficient for axis-induction. The latter fusion molecule is blocked by dominant negative LEF-1 but not by excess cadherin indicating that all events parallel or upstream of the transactivation step mediated by beta-catenin are dispensable for Wnt-signaling. Moreover, beta-catenin can be replaced by a heterologous transactivator. Apparently, the ultimate function of beta-catenin in Wnt signaling is to recruit the basal transcription machinery to promoter regions of specific target genes.

???displayArticle.pubmedLink??? 10330485



Species referenced: Xenopus laevis
Genes referenced: lef1 sia1


???attribute.lit??? ???displayArticles.show???