title: Graded Egfr activity patterns the Drosophila eggshell independently of autocrine feedback.
abstract: The pattern of the Drosophila eggshell is determined by the establishment of a complex and stereotyped pattern of cell fates in the follicular epithelium of the ovary. Localized activation of the Epidermal growth factor receptor (Egfr) is essential for this patterning. Modulation of Egfr pathway activity in time and space determines distinct fates at their appropriate locations, but the details of how Egfr signaling is regulated and how the profile of Egfr activity corresponds to cell fate remain unclear. Here we analyze the effect of loss of various Egfr regulators and targets on follicle cell patterning, using a marker for follicle cell fate, and on the mature eggshell phenotype, using a novel eggshell marker. We show, contrary to current patterning models, that feedback regulation of Egfr activity by the autocrine ligand Spitz and the inhibitor Argos is not necessary for patterning. Given the cell-autonomous nature of the mutant phenotypes we observed, we propose instead that the pattern of cell fates is generated by spatial information derived directly from the germline ligand Gurken, without a requirement for subsequent patterning by diffusible Egfr regulators in the follicular epithelium.
authors.affiliation: Department of Biology, McGill University, 1205 Doctor Penfield Avenue, Montréal, Quebec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Boisclair Lachance
authors.forename: Mariana
authors.initials: M
authors.lastname: Fregoso Lomas
authors.forename: Aliaa
authors.initials: A
authors.lastname: Eleiche
authors.forename: Phoenix
authors.initials: P
authors.lastname: Bouchard Kerr
authors.forename: Laura A
authors.initials: LA
authors.lastname: Nilson
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019898:Autocrine Communication; D015415:Biomarkers / Q000378:metabolism; D019521:Body Patterning / Q000502:physiology*; D019070:Cell Lineage; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000502:physiology; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D010641:Phenotype; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C105790:mirr protein, Drosophila; C110486:sty protein, Drosophila; C075638:aos protein, Drosophila; C076026:spi protein, Drosophila; D004815:Epidermal Growth Factor; D066246:ErbB Receptors