title: Hedgehog signaling and the retina: insights into the mechanisms controlling the proliferative properties of neural precursors.
abstract: Hedgehog signaling has been linked to cell proliferation in a variety of systems; however, its effects on the cell cycle have not been closely studied. In the vertebrate retina, Hedgehog's effects are controversial, with some reports emphasizing increased proliferation and others pointing to a role in cell cycle exit. Here we demonstrate a novel role for Hedgehog signaling in speeding up the cell cycle in the developing retina by reducing the length of G1 and G2 phases. These fast cycling cells tend to exit the cell cycle early. Conversely, retinal progenitors with blocked Hedgehog signaling cycle more slowly, with longer G1 and G2 phases, and remain in the cell cycle longer. Hedgehog may modulate cell cycle kinetics through activation of the key cell cycle activators cyclin D1, cyclin A2, cyclin B1, and cdc25C. These findings support a role for Hedgehog in regulating the conversion from slow cycling stem cells to fast cycling transient amplifying progenitors that are closer to cell cycle exit.
authors.affiliation: Laboratoire Gènes, Développement et Neurogenèse, Université Paris XI, UMR Centre national de la Recherche Scientifique (CNRS) 8080, Orsay, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Locker
authors.forename: Michalis
authors.initials: M
authors.lastname: Agathocleous
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Amato
authors.forename: Karine
authors.initials: K
authors.lastname: Parain
authors.forename: William A
authors.initials: WA
authors.lastname: Harris
authors.forename: Muriel
authors.initials: M
authors.lastname: Perron
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000819:agonists / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D053823:Hedgehog Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D012160:Retina / Q000166:cytology / Q000254:growth & development*; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D014981:Xenopus
chemical_list: D018797:Cell Cycle Proteins; D053823:Hedgehog Proteins