title: Delta-promoted filopodia mediate long-range lateral inhibition in Drosophila.
abstract: Drosophila thoracic mechanosensory bristles originate from cells that are singled out from 'proneural' groups of competent epithelial cells. Neural competence is restricted to individual sensory organ precursors (SOPs) by Delta/Notch-mediated 'lateral inhibition', whereas other cells in the proneural field adopt an epidermal fate. The precursors of the large macrochaetes differentiate separately from individual proneural clusters that comprise about 20-30 cells or as heterochronic pairs from groups of more than 100 cells, whereas the precursors of the small regularly spaced microchaetes emerge from even larger proneural fields. This indicates that lateral inhibition might act over several cell diameters; it was difficult to reconcile with the fact that the inhibitory ligand Delta is membrane-bound until the observation that SOPs frequently extend thin processes offered an attractive hypothesis. Here we show that the extension of these planar filopodia--a common attribute of wing imaginal disc cells--is promoted by Delta and that their experimental suppression reduces Notch signalling in distant cells and increases bristle density in large proneural groups, showing that these membrane specializations mediate long-range lateral inhibition.
authors.affiliation: Laboratoire Dynamique Moléculaire des Interactions Membranaires, CNRS UMR 5539, Université Montpellier II C.C. 107, Place Eugène Bataillon, 34095 Montpellier cedex 5, France [corrected]
authors.forename: Cyrille
authors.initials: C
authors.lastname: De Joussineau
authors.forename: Jonathan
authors.initials: J
authors.lastname: Soulé
authors.forename: Marianne
authors.initials: M
authors.lastname: Martin
authors.forename: Christelle
authors.initials: C
authors.lastname: Anguille
authors.forename: Philippe
authors.initials: P
authors.lastname: Montcourrier
authors.forename: Daniel
authors.initials: D
authors.lastname: Alexandre
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism*; D051880:Receptors, Notch; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D000099149:Ezrin
chemical_list: D003598:Cytoskeletal Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins; D010750:Phosphoproteins; D051880:Receptors, Notch; D000099149:Ezrin; C497759:N protein, Drosophila; C064045:delta protein