title: Mapping neurogenesis onset in the optic tectum of Xenopus laevis.
abstract: Neural progenitor cells have a central role in the development and evolution of the vertebrate brain. During early brain development, neural progenitors first expand their numbers through repeated proliferative divisions and then begin to exhibit neurogenic divisions. The transparent and experimentally accessible optic tectum of Xenopus laevis is an excellent model system for the study of the cell biology of neurogenesis, but the precise spatial and temporal relationship between proliferative and neurogenic progenitors has not been explored in this system. Here we construct a spatial map of proliferative and neurogenic divisions through lineage tracing of individual progenitors and their progeny. We find a clear spatial separation of proliferative and neurogenic progenitors along the anterior-posterior axis of the optic tectum, with proliferative progenitors located more posteriorly and neurogenic progenitors located more anteriorly. Since individual progenitors are repositioned toward more anterior locations as they mature, this spatial separation likely reflects an increasing restriction in the proliferative potential of individual progenitors. We then examined whether the transition from proliferative to neurogenic behavior correlates with cellular properties that have previously been implicated in regulating neurogenesis onset. Our data reveal that the transition from proliferation to neurogenesis is associated with a small change in cleavage plane orientation and a more pronounced change in cell cycle kinetics in a manner reminiscent of observations from mammalian systems. Our findings highlight the potential to use the optic tectum of Xenopus laevis as an accessible system for the study of the cell biology of neurogenesis. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1328-1341, 2016.
authors.affiliation: Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom.|Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom.|Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom.
authors.forename: Leah
authors.initials: L
authors.lastname: Herrgen
authors.affiliation: Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, United Kingdom.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Akerman
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D058953:Neural Stem Cells / Q000166:cytology*; D055495:Neurogenesis / Q000502:physiology*; D009457:Neuroglia / Q000166:cytology; D009474:Neurons / Q000166:cytology*; D013477:Superior Colliculi / Q000254:growth & development*; D029867:Xenopus Proteins / Q000378:metabolism; D014982:Xenopus laevis / Q000254:growth & development*
chemical_list: D029867:Xenopus Proteins
keywords: Xenopus laevis; cell cycle length; cleavage plane orientation; neural progenitor; neurogenesis