title: Direct control of neurogenesis by selector factors in the fly eye: regulation of atonal by Ey and So.
abstract: During eye development, the selector factors of the Eyeless/Pax6 or Retinal Determination (RD) network control specification of organ-type whereas the bHLH-type proneural factor Atonal drives neurogenesis. Although significant progress has been made in dissecting the acquisition of ;eye identity' at the transcriptional level, the molecular mechanisms underlying the progression from neuronal progenitor to differentiating neuron remain unclear. A recently proposed model for the integration of organ specification and neurogenesis hypothesizes that atonal expression in the eye is RD-network-independent and that Eyeless works in parallel or downstream of atonal to modify the neurogenetic program. We show here that distinct cis-regulatory elements control atonal expression specifically in the eye and that the RD factors Eyeless and Sine oculis function as direct regulators. We find that these transcription factors interact in vitro and provide indirect evidence that this interaction may be required in vivo. The subordination of neurogenesis to the RD pathway in the eye provides a direct mechanism for the coordination of neurogenesis and tissue specification during sensory organ formation.
authors.affiliation: Ophthalmology Department, Harvard Medical School/MEEI, Boston, MA 02114, USA.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Zhang
authors.forename: Swati
authors.initials: S
authors.lastname: Ranade
authors.forename: Chuan Qi
authors.initials: CQ
authors.lastname: Cai
authors.forename: Christopher
authors.initials: C
authors.lastname: Clouser
authors.forename: Francesca
authors.initials: F
authors.lastname: Pignoni
mesh_terms: D024509:3' Flanking Region; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D005075:Biological Evolution; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic; D005123:Eye / Q000196:embryology / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017956:Photoreceptor Cells, Invertebrate / Q000196:embryology*; D011485:Protein Binding; D015398:Signal Transduction
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; C087345:So protein, Drosophila; C082142:ato protein, Drosophila; C113278:ey protein, Drosophila