Distinct beta-catenins mediate adhesion and signalling functions in C. elegans.

In flies and vertebrates, Armadillo/beta-catenin forms a complex with Tcf/Lef-1 transcription factors, serving as an essential co-activator to mediate Wnt signalling. It also associates with cadherins to mediate adhesion. In Caenorhabditis elegans, three putative beta-catenin homologues have been identified: WRM-1, BAR-1 and HMP-2. WRM-1 and the Tcf homologue POP-1 mediate ...
Wnt signalling by a mechanism that has challenged current views of the Wnt pathway. Here we show that BAR-1 is the only beta-catenin homologue that interacts directly with POP-1. BAR-1 mediates Wnt signalling by forming a BAR-1/POP-1 bipartite transcription factor that activates expression of Wnt target genes such as the Hox gene mab-5. HMP-2 is the only beta-catenin homologue that interacts with the single cadherin of C. elegans, HMR-1. We conclude that a canonical Wnt pathway exists in C. elegans. Furthermore, our analysis shows that the functions of C. elegans beta-catenins in adhesion and in signalling are performed by separate proteins.
Mesh Terms:
Animals, Animals, Genetically Modified, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Cell Adhesion, Cell Line, Cloning, Molecular, Cytoskeletal Proteins, DNA-Binding Proteins, Gene Expression Regulation, Genes, Helminth, Genes, Reporter, Helminth Proteins, High Mobility Group Proteins, Homeodomain Proteins, Mice, Molecular Sequence Data, Mutation, Proto-Oncogene Proteins, Signal Transduction, Trans-Activators, Transcription Factors, Two-Hybrid System Techniques, Wnt Proteins, Zebrafish Proteins, beta Catenin
Nature
Date: Aug. 03, 2000
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