title: Pyramidal neurons of upper cortical layers generated by NEX-positive progenitor cells in the subventricular zone.
abstract: The generation of pyramidal neurons in the mammalian neocortex has been attributed to proliferating progenitor cells within the ventricular zone (VZ). Recently, the subventricular zone (SVZ) has been recognized as a possible source of migratory neurons in brain slice preparations, but the relevance of these observations for the developing neocortex in vivo remains to be defined. Here, we demonstrate that a subset of progenitor cells within the SVZ of the mouse neocortex can be molecularly defined by Cre recombinase expression under control of the NEX/Math2 locus, a neuronal basic helix-loop-helix gene that by itself is dispensable for cortical development. NEX-positive progenitors are generated by VZ cells, move into the SVZ, and undergo multiple asymmetrical and symmetrical cell divisions that produce a fraction of the neurons in the upper cortical layers. Our data suggest that NEX-positive progenitors within the SVZ are committed to a glutamatergic neuronal fate and have evolved to expand the number of cortical output neurons that is characteristic for the mammalian forebrain.
authors.affiliation: Department of Morphological Brain Science and Laboratory of Immunological Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Sheng-Xi
authors.initials: SX
authors.lastname: Wu
authors.forename: Sandra
authors.initials: S
authors.lastname: Goebbels
authors.forename: Kouichi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakamura
authors.forename: Kouhei
authors.initials: K
authors.lastname: Kometani
authors.forename: Nagahiro
authors.initials: N
authors.lastname: Minato
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
authors.forename: Klaus-Armin
authors.initials: KA
authors.lastname: Nave
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Tamamaki
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000096:biosynthesis* / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage / Q000502:physiology; D002478:Cells, Cultured; D002552:Cerebral Ventricles / Q000166:cytology*; D017930:Genes, Reporter; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D019579:Neocortex / Q000166:cytology / Q000196:embryology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000502:physiology; D017966:Pyramidal Cells / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; C110701:Neurod6 protein, mouse