title: A Notch/Delta-dependent relay mechanism establishes anterior-posterior polarity in Drosophila.
abstract: The anterior-posterior axis of Drosophila becomes polarized early in oogenesis, when the oocyte moves to the posterior of the germline cyst because it preferentially adheres to posterior follicle cells. The source of this asymmetry is unclear, however, since anterior and posterior follicle cells are equivalent until midoogenesis, when Gurken signaling from the oocyte induces posterior fate. Here, we show that asymmetry arises because each cyst polarizes the next cyst through a series of posterior to anterior inductions. Delta signaling from the older cyst induces the anterior polar follicle cells, the anterior polar cells signal through the JAK/STAT pathway to induce the formation of the stalk between adjacent cysts, and the stalk polarizes the younger anterior cyst by inducing the shape change and preferential adhesion that position the oocyte at the posterior. The anterior-posterior axis is therefore established by a relay mechanism, which propagates polarity from one cyst to the next.
authors.affiliation: The Wellcome Trust/Cancer Research UK Institute and Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, United Kingdom.
authors.forename: Isabel L
authors.initials: IL
authors.lastname: Torres
authors.forename: Hernán
authors.initials: H
authors.lastname: López-Schier
authors.forename: Daniel
authors.initials: D
authors.lastname: St Johnston
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D003560:Cysts / Q000378:metabolism; D004330:Drosophila / Q000196:embryology; D029721:Drosophila Proteins; D004627:Embryonic Induction / Q000502:physiology; D005260:Female; D018095:Germ-Line Mutation / Q000235:genetics / Q000502:physiology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D009865:Oocytes / Q000166:cytology; D009866:Oogenesis / Q000502:physiology; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology; D051880:Receptors, Notch; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; C064045:delta protein