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Groucho oligomerization is required for repression in vivo
Haiyun Song1, Peleg Hasson, Ze'ev Paroush
1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA.
Molecular and Cellular Biology
|May 4, 2004
Summary
The Drosophila Groucho (Gro) Q domain uses two coiled-coil motifs for oligomerization and repression in vivo. Disrupting these motifs impairs Gro function, linking corepressor oligomerization to developmental gene regulation.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Drosophila Groucho (Gro) is a key metazoan corepressor involved in development.
- The Gro Q domain was previously linked to repression and homotetramerization in cell culture.
Purpose of the Study:
- To investigate the role of the Q domain's coiled-coil motifs in Gro oligomerization and repression in vivo.
- To establish a direct link between corepressor oligomerization and gene repression during development.
Main Methods:
- Site-directed mutagenesis of putative coiled-coil motifs within the Gro Q domain.
- Assessing oligomerization using tetramer formation and higher-order oligomerization assays.
- Evaluating repression activity via Gal4-Gro fusion proteins in S2 cells and observing developmental defects in Drosophila.
Main Results:
- The Gro Q domain contains two coiled-coil motifs essential for tetramerization and higher-order oligomerization.
- Mutating hydrophobic faces of these motifs abolished oligomerization and repression, while single mutations weakened repression.
- Overexpression of oligomerization-competent Gro caused developmental defects and ectopic gene repression in fly wings.
Conclusions:
- Corepressor oligomerization, mediated by specific coiled-coil motifs in the Gro Q domain, is critical for repression in vivo.
- This study provides direct evidence linking corepressor oligomerization to developmental gene regulation in a whole organism.