title: FAK-mediated extracellular signals are essential for interkinetic nuclear migration and planar divisions in the neuroepithelium.
abstract: During the development of the vertebrate nervous system, mitosis of neural progenitor cells takes place near the lumen, the apical side of the neural tube, through a characteristic movement of nuclei known as interkinetic nuclear migration (INM). Furthermore, during the proliferative period, neural progenitor cells exhibit planar cell divisions to produce equivalent daughter cells. Here, we examine the potential role of extracellular signals in INM and planar divisions using the medaka mutant tacobo (tab). This tab mutant shows pleiotropic phenotypes, including neurogenesis, and positional cloning identified tab as laminin gamma1 (lamc1), providing a unique framework to study the role of extracellular signals in neurogenesis. In tab mutant neural tubes, a number of nuclei exhibit abnormal patterns of migration leading to basally mislocalized mitosis. Furthermore, the orientation of cell division near the apical surface is randomized. Probably because of these defects, neurogenesis is accelerated in the tab neural tube. Detailed analyses demonstrate that extracellular signals mediated by the FAK pathway regulate INM and planar divisions in the neuroepithelium, possibly through interaction with the intracellular dynein-motor system.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Tsuda
authors.forename: Tadao
authors.initials: T
authors.lastname: Kitagawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takashima
authors.forename: Shuichi
authors.initials: S
authors.lastname: Asakawa
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Shimizu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mitani
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shima
authors.forename: Makiko
authors.initials: M
authors.lastname: Tsutsumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hori
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Naruse
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D029941:Fish Proteins / Q000378:metabolism*; D015151:Immunoblotting; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D046569:Neuroepithelial Cells / Q000166:cytology / Q000378:metabolism*; D009990:Oryzias; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D029941:Fish Proteins