title: Osa modulates the expression of Apterous target genes in the Drosophila wing.
abstract: The establishment of the dorsal-ventral axis of the Drosophila wing depends on the activity of the LIM-homeodomain protein Apterous. Apterous activity depends on the formation of a higher order complex with its cofactor Chip to induce the expression of its target genes. Apterous activity levels are modulated during development by dLMO. Expression of dLMO in the Drosophila wing is regulated by two distinct Chip dependent mechanisms. Early in development, Chip bridges two molecules of Apterous to induce expression of dLMO in the dorsal compartment. Later in development, Chip, independently of Apterous, is required for expression of dLMO in the wing pouch. We have conducted a modular P-element based EP (enhancer/promoter) misexpression screen to look for genes involved in Apterous activity. We have found Osa, a member of the Brahma chromatin-remodeling complex, as a positive modulator of Apterous activity in the Drosophila wing. Osa mediates activation of some Apterous target genes and repression of others, including dLMO. Osa has been shown to bind Chip. We propose that Chip recruits Osa to the Apterous target genes, thus mediating activation or repression of their expression.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. mmilan@pcb.ub.es
authors.forename: Marco
authors.initials: M
authors.lastname: Milán
authors.forename: Thu Thuy
authors.initials: TT
authors.lastname: Pham
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Cohen
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D004330:Drosophila / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D060850:LIM-Homeodomain Proteins; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014921:Wings, Animal / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*
chemical_list: C096249:Bx protein, Drosophila; C108740:Chi protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C074459:ap protein, Drosophila; C117995:osa protein, Drosophila