Negative regulation of axis formation and Wnt signaling in Xenopus embryos by the F-box/WD40 protein beta TrCP.
Screening a maternal Xenopus expression library for activities that synergize with low levels of injected beta-catenin, we have isolated a clone encoding the C-terminal end of x-beta TrCP-2, a highly conserved protein belonging to the F-box/WD40 family of ubiquitin-ligase specificity factors. We show that x-beta TrCP-2 expression reduces dorsal axis formation in Xenopus embryos. A dominant negative mutant lacking the F-box triggers the opposite effect, inducing secondary axes and activating the expression of Wnt responsive genes in ectodermal explants. In light of the existence of beta TrCP transcripts associated with the vegetal cortex, we propose that beta TrCP plays a fundamental role in the establishment of the dorsal determinants during cortical rotation in Xenopus.
Lagna
G
G
Laboratory of Molecular Embryology, Rockefeller University, New York, NY 10021, USA.
Carnevali
F
F
Marchioni
M
M
Hemmati-Brivanlou
A
A
D000818:Animals; D019521:Body Patterning; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015723:Gene Library; D038362:Glycogen Synthase Kinase 3; D008957:Models, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators; D051153:Wnt Proteins; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D044844:beta-Transducin Repeat-Containing Proteins
C471646:BTRC protein, Xenopus; C495266:CTNNB1 protein, Xenopus; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D044844:beta-Transducin Repeat-Containing Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D019204:GTP-Binding Proteins