Wingless blocks bristle formation and morphogenetic furrow progression in the eye through repression of Daughterless.
In the developing eye, wingless activity represses proneural gene expression (and thus interommatidial bristle formation) and positions the morphogenetic furrow by blocking its initiation in the dorsal and ventral regions of the presumptive eye. We provide evidence that wingless mediates both effects, at least in part, through repression of the basic helix-loop-helix protein Daughterless. daughterless is required for high proneural gene expression and furrow progression. Ectopic expression of wingless blocks Daughterless expression in the proneural clusters. This repression, and that of furrow progression, can be mimicked by an activated form of armadillo and blocked by a dominant negative form of pangolin/TCF. Placing daughterless under the control of a heterologous promoter blocks the ability of ectopic wingless to inhibit bristle formation and furrow progression. hedgehog and decapentapleigic could not rescue the wingless furrow progression block, indicating that wingless acts downstream of these genes. In contrast, Atonal and Scute, which are thought to heterodimerize with Daughterless to promote furrow progression and bristle formation, respectively, can block ectopic wingless action. These results are summarized in a model where daughterless is a major, but probably not the only, target of wingless action in the eye.
Cadigan
Kenneth M
KM
Howard Hughes Medical Institute and the Department of Developmental Biology, Stanford University School of Medicine, Beckman Center,Stanford, California 94305, USA. cadigan@umich.edu
Jou
Austin D
AD
Nusse
Roel
R
D000818:Animals; D030801:Animals, Genetically Modified; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins / Q000235:genetics*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D005123:Eye / Q000196:embryology* / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D005809:Genes, Regulator; D019476:Insect Proteins / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D009024:Morphogenesis; D009154:Mutation; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics*; D051155:Wnt1 Protein
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D051155:Wnt1 Protein; C090080:Da protein, Drosophila; C082142:ato protein, Drosophila; C063577:emc protein, Drosophila; C489235:hairy protein, Drosophila; C089197:sc protein, Drosophila; C074622:wg protein, Drosophila; C061841:hairy protein, insect