Osa-containing Brahma chromatin remodeling complexes are required for the repression of wingless target genes.
The Wingless signaling pathway directs many developmental processes in Drosophila by regulating the expression of specific downstream target genes. We report here that the product of the trithorax group gene osa is required to repress such genes in the absence of the Wingless signal. The Wingless-regulated genes nubbin, Distal-less, and decapentaplegic and a minimal enhancer from the Ultrabithorax gene are misexpressed in osa mutants and repressed by ectopic Osa. Osa-mediated repression occurs downstream of the up-regulation of Armadillo but is sensitive both to the relative levels of activating Armadillo/Pangolin and repressing Groucho/Pangolin complexes present and to the responsiveness of the promoter to Wingless. Osa functions as a component of the Brahma chromatin-remodeling complex; other components of this complex are likewise required to repress Wingless target genes. These results suggest that altering the conformation of chromatin is an important mechanism by which Wingless signaling activates gene expression.
Collins
R T
RT
Skirball Institute of Biomolecular Medicine and Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA.
Treisman
J E
JE
D000818:Animals; D051186:Armadillo Domain Proteins; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin / Q000378:metabolism* / Q000648:ultrastructure; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D004742:Enhancer Elements, Genetic; D005260:Female; D018507:Gene Expression Regulation, Developmental; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009154:Mutation; D050809:POU Domain Factors; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D051155:Wnt1 Protein
D051186:Armadillo Domain Proteins; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D018398:Homeodomain Proteins; D019476:Insect Proteins; D050809:POU Domain Factors; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051155:Wnt1 Protein; C495305:ARM protein, Drosophila; C066177:Ubx protein, Drosophila; C086469:brm protein, Drosophila; C117261:distal-less protein, insect; C064196:dpp protein, Drosophila; C091023:gro protein, Drosophila; C104121:nub protein, Drosophila; C117995:osa protein, Drosophila; C074622:wg protein, Drosophila; C512966:HDAC1 protein, Drosophila