title: Tufted is a gain-of-function allele that promotes ectopic expression of the proneural gene amos in Drosophila.
abstract: The Tufted(1) (Tft(1)) dominant mutation promotes the generation of ectopic bristles (macrochaetae) in the dorsal mesothorax of Drosophila. Here we show that Tft(1) corresponds to a gain-of-function allele of the proneural gene amos that is associated with a chromosomal aberration at 36F-37A. This causes ectopic expression of amos in large domains of the lateral-dorsal embryonic ectoderm, which results in supernumerary neurons of the PNS, and in the notum region of the third instar imaginal wing, which gives rise to the mesothoracic extra bristles. Revertants of Tft(1), which lack ectopic neurons and bristles, do not show ectopic expression of amos. One revertant is a loss-of-function allele of amos and has a recessive phenotype in the embryonic PNS. Our results suggest that both normal and ectopic Tft(1) bristles are generated following similar rules, and both are subjected to Notch-mediated lateral inhibition. The ability of Tft(1) bristles to appear close together may be due to amos having a stronger proneural capacity than that of other proneural genes like asense and scute. This ability might be related to the wild-type function of amos in promoting development of large clusters of closely spaced olfactory sensilla.
authors.affiliation: Centro de Biología Molecular Severo Ochoa, CSIC and Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Villa-Cuesta
authors.forename: Joaquín
authors.initials: J
authors.lastname: de Navascués
authors.forename: Mar
authors.initials: M
authors.lastname: Ruiz-Gómez
authors.forename: Ruth
authors.initials: R
authors.lastname: Diez del Corral
authors.forename: María
authors.initials: M
authors.lastname: Domínguez
authors.forename: José Félix
authors.initials: JF
authors.lastname: de Celis
authors.forename: Juan
authors.initials: J
authors.lastname: Modolell
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009421:Nervous System Malformations / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C405512:Amos protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C407353:ase protein, Drosophila; C089197:sc protein, Drosophila