Originally published as Genetics Published Articles Ahead of Print on April 19, 2006.

Genetics, Vol. 173, 849-861, June 2006, Copyright © 2006
doi:10.1534/genetics.105.055012

Genetic Interactions Among scribbler, Atrophin and groucho in Drosophila Uncover Links in Transcriptional Repression

Amy Wehn and Gerard Campbell1

Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260

1 Corresponding author: Department of Biological Sciences, University of Pittsburgh, 203 Life Sciences Annex, 4259 Fifth Ave., Pittsburgh, PA 15260.
E-mail: camp{at}pitt.edu

In eukaryotes, the ability of DNA-binding proteins to act as transcriptional repressors often requires that they recruit accessory proteins, known as corepressors, which provide the activity responsible for silencing transcription. Several of these factors have been identified, including the Groucho (Gro) and Atrophin (Atro) proteins in Drosophila. Here we demonstrate strong genetic interactions between gro and Atro and also with mutations in a third gene, scribbler (sbb), which encodes a nuclear protein of unknown function. We show that mutations in Atro and Sbb have similar phenotypes, including upregulation of the same genes in imaginal discs, which suggests that Sbb cooperates with Atro to provide repressive activity. Comparison of gro and Atro/sbb mutant phenotypes suggests that they do not function together, but instead that they may interact with the same transcription factors, including Engrailed and C15, to provide these proteins with maximal repressive activity.