The specificity of proneural genes in determining Drosophila sense organ identity.
The proneural genes (atonal and the genes of the achaete-scute complex (AS-C)) are required for the selection of sense organ precursors. They also endow these precursors with sense organ subtype information. In most of the ectoderm, atonal is required for precursors of chordotonal sense organs, whereas AS-C are required for those of most external sense organs, such as bristles. To address the question of how proneural genes influence subtype identity, we have made use of the Gal4/UAS system of misexpression. Unlike previous misexpression experiments, we found that under specific conditions of misexpression, atonal shows high subtype specificity of ectopic sense organ formation. Moreover, atonal can even transform wild-type external sense organs to chordotonal organs, although scute cannot perform the reciprocal transformation. Our evidence demonstrates that atonal's subtype determining role is not to activate directly chordotonal fate, but to repress the activation of cut, a gene that is necessary for external sense organ fate, thereby freeing its precursors to follow the alternative chordotonal organ fate.
Institute of Cell and Molecular Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK. andrew.jarman@ed.ac.uk
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D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000254:growth & development*; D029721:Drosophila Proteins; D004627:Embryonic Induction; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012679:Sense Organs / Q000254:growth & development*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C089199:ac protein, Drosophila; C082142:ato protein, Drosophila; C066381:ct protein, Drosophila; C089197:sc protein, Drosophila