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Citation
Cox, R.T., Pai, L.M., Kirkpatrick, C., Stein, J., Peifer, M. (1999). Roles of the C terminus of armadillo in wingless signaling in Drosophila.  Genetics 153(1): 319--332.
FlyBase ID
FBrf0111349
Publication Type
Research paper
Abstract

Drosophila melanogaster Armadillo and its vertebrate homolog beta-catenin play multiple roles during development. Both are components of cell-cell adherens junctions and both transduce Wingless (Wg)/Wnt intercellular signals. The current model for Wingless signaling proposes that Armadillo binds the DNA-binding protein dTCF, forming a bipartite transcription factor that activates Wingless-responsive genes. In this model, Armadillo's C-terminal domain is proposed to serve an essential role as a transcriptional activation domain. In Xenopus, however, overexpression of C-terminally truncated beta-catenin activates Wnt signaling, suggesting that the C-terminal domain might not be essential. We reexamined the function of Armadillo's C terminus in Wingless signaling. We found that C-terminally truncated mutant Armadillo has a deficit in Wg-signaling activity, even when corrected for reduced protein levels. However, we also found that Armadillo proteins lacking all or part of the C terminus retain some signaling ability if overexpressed, and that mutants lacking different portions of the C-terminal domain differ in their level of signaling ability. Finally, we found that the C terminus plays a role in Armadillo protein stability in response to Wingless signal and that the C-terminal domain can physically interact with the Arm repeat region. These data suggest that the C-terminal domain plays a complex role in Wingless signaling and that Armadillo recruits the transcriptional machinery via multiple contact sites, which act in an additive fashion.

PubMed ID
PubMed Central ID
PMC1460731 (PMC) (EuropePMC)
DOI
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    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    Genetics
    Title
    Genetics
    Publication Year
    1916-
    ISBN/ISSN
    0016-6731
    Data From Reference