title: Hairless-mediated repression of notch target genes requires the combined activity of Groucho and CtBP corepressors.
abstract: Notch signal transduction centers on a conserved DNA-binding protein called Suppressor of Hairless [Su(H)] in Drosophila species. In the absence of Notch activation, target genes are repressed by Su(H) acting in conjunction with a partner, Hairless, which contains binding motifs for two global corepressors, CtBP and Groucho (Gro). Usually these corepressors are thought to act via different mechanisms; complexed with other transcriptional regulators, they function independently and/or redundantly. Here we have investigated the requirement for Gro and CtBP in Hairless-mediated repression. Unexpectedly, we find that mutations inactivating one or the other binding motif can have detrimental effects on Hairless similar to those of mutations that inactivate both motifs. These results argue that recruitment of one or the other corepressor is not sufficient to confer repression in the context of the Hairless-Su(H) complex; Gro and CtBP need to function in combination. In addition, we demonstrate that Hairless has a second mode of repression that antagonizes Notch intracellular domain and is independent of Gro or CtBP binding.
authors.affiliation: Anette Preiss, Institut für Genetik (240), Universität Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany.
authors.forename: Anja C
authors.initials: AC
authors.lastname: Nagel
authors.forename: Alena
authors.initials: A
authors.lastname: Krejci
authors.forename: Gennady
authors.initials: G
authors.lastname: Tenin
authors.forename: Alejandro
authors.initials: A
authors.lastname: Bravo-Patiño
authors.forename: Sarah
authors.initials: S
authors.lastname: Bray
authors.forename: Dieter
authors.initials: D
authors.lastname: Maier
authors.forename: Anette
authors.initials: A
authors.lastname: Preiss
mesh_terms: D000429:Alcohol Oxidoreductases; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D009154:Mutation / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014921:Wings, Animal / Q000002:abnormalities / Q000378:metabolism
chemical_list: D000429:Alcohol Oxidoreductases; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D010750:Phosphoproteins; D051880:Receptors, Notch; D012097:Repressor Proteins; D014157:Transcription Factors; C091023:gro protein, Drosophila; C076560:H protein, Drosophila; C096794:C-terminal binding protein