title: Characterization of tailless functions during Drosophila optic lobe formation.
abstract: Brain development goes through phases of proliferative growth and differentiation to ensure the formation of correct number and variety of neurons. How and when naïve neuroepithelial cells decide to enter a differentiation pathway remains poorly understood. In the Drosophila visual system, four optic ganglia emerge from neuroepithelia of the inner (IPC) and outer (OPC) proliferation centers. Here we demonstrate that the orphan nuclear receptor Tailless (Tll) is a key factor for the development of all optic ganglia. We describe tll expression during larval optic lobe development in unprecedented detail and find a spatiotemporally dynamic pattern. In the larval OPC, symmetrically dividing neuroepithelial cells transform into asymmetrically dividing medulla neuroblast and into lamina precursor cells in a precisely regulated fashion. Using genetic manipulations we found that tll is required for proper neuroepithelium morphology and neuroepithelial cell survival. We show that tll regulates the precise timing of the transition from neuroepithelial cells to medulla neuroblasts. In particular, however, we demonstrate that tll has a crucial role for the specification of lamina precursor cells. We propose that the Tll/Tlx transcription factors have an evolutionary conserved role in regulating neural precursor cell states in the Drosophila optic lobe and in the mammalian retina.
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland.
authors.forename: Oriane
authors.initials: O
authors.lastname: Guillermin
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Perruchoud
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland. Electronic address: simon.sprecher@unifr.ch.
authors.forename: Simon G
authors.initials: SG
authors.lastname: Sprecher
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland. Electronic address: boris.egger@unifr.ch.
authors.forename: Boris
authors.initials: B
authors.lastname: Egger
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002470:Cell Survival; D003433:Crosses, Genetic; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology*; D004847:Epithelial Cells / Q000166:cytology; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology; D046569:Neuroepithelial Cells / Q000166:cytology; D009474:Neurons / Q000166:cytology; D009899:Optic Lobe, Nonmammalian / Q000502:physiology*; D051880:Receptors, Notch / Q000378:metabolism; D012097:Repressor Proteins / Q000502:physiology*; D012160:Retina / Q000196:embryology; D013234:Stem Cells / Q000166:cytology
chemical_list: D029721:Drosophila Proteins; D051880:Receptors, Notch; D012097:Repressor Proteins; C074090:TLL protein, Drosophila; D049452:Green Fluorescent Proteins
keywords: Drosophila; Neural stem cell; Nuclear receptor; Optic lobe; Visual system; tailless