title: Conserved miR-8/miR-200 defines a glial niche that controls neuroepithelial expansion and neuroblast transition.
abstract: Neuroepithelial cell proliferation must be carefully balanced with the transition to neuroblast (neural stem cell) to control neurogenesis. Here, we show that loss of the Drosophila microRNA mir-8 (the homolog of vertebrate miR-200 family) results in both excess proliferation and ectopic neuroblast transition. Unexpectedly, mir-8 is expressed in a subpopulation of optic-lobe-associated cortex glia that extend processes that ensheath the neuroepithelium, suggesting that glia cells communicate with the neuroepithelium. We provide evidence that miR-8-positive glia express Spitz, a transforming growth factor α (TGF-α)-like ligand that triggers epidermal growth factor receptor (EGFR) activation to promote neuroepithelial proliferation and neuroblast formation. Further, our experiments suggest that miR-8 ensures both a correct glial architecture and the spatiotemporal control of Spitz protein synthesis via direct binding to Spitz 3' UTR. Together, these results establish glial-derived cues as key regulatory elements in the control of neuroepithelial cell proliferation and the neuroblast transition.
authors.affiliation: Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain. Electronic address: j.morante@umh.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Morante
authors.affiliation: Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain.
authors.forename: Diana M
authors.initials: DM
authors.lastname: Vallejo
authors.affiliation: Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA.
authors.forename: Claude
authors.initials: C
authors.lastname: Desplan
authors.affiliation: Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Dominguez
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics*; D058953:Neural Stem Cells; D046569:Neuroepithelial Cells / Q000378:metabolism; D055495:Neurogenesis; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D018010:Receptors, Invertebrate Peptide / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics
chemical_list: D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D008565:Membrane Proteins; D035683:MicroRNAs; D018010:Receptors, Invertebrate Peptide; C526630:MIRN8 microRNA, Drosophila; C076026:spi protein, Drosophila; D004815:Epidermal Growth Factor; C066532:Egfr protein, Drosophila; D066246:ErbB Receptors