Regulation of interkinetic nuclear migration by cell cycle-coupled active and passive mechanisms in the developing brain

EMBO J. 2011 May 4;30(9):1690-704. doi: 10.1038/emboj.2011.81. Epub 2011 Mar 25.

Abstract

A hallmark of neurogenesis in the vertebrate brain is the apical-basal nuclear oscillation in polarized neural progenitor cells. Known as interkinetic nuclear migration (INM), these movements are synchronized with the cell cycle such that nuclei move basally during G1-phase and apically during G2-phase. However, it is unknown how the direction of movement and the cell cycle are tightly coupled. Here, we show that INM proceeds through the cell cycle-dependent linkage of cell-autonomous and non-autonomous mechanisms. During S to G2 progression, the microtubule-associated protein Tpx2 redistributes from the nucleus to the apical process, and promotes nuclear migration during G2-phase by altering microtubule organization. Thus, Tpx2 links cell-cycle progression and autonomous apical nuclear migration. In contrast, in vivo observations of implanted microbeads, acute S-phase arrest of surrounding cells and computational modelling suggest that the basal migration of G1-phase nuclei depends on a displacement effect by G2-phase nuclei migrating apically. Our model for INM explains how the dynamics of neural progenitors harmonize their extensive proliferation with the epithelial architecture in the developing brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / embryology*
  • Cell Cycle / physiology*
  • Cell Nucleus / physiology*
  • Cell Polarity / physiology
  • Cell Proliferation
  • DNA Primers / genetics
  • Gene Knockdown Techniques
  • Mice
  • Microscopy, Fluorescence
  • Microspheres
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / physiology*
  • Models, Molecular*
  • Neural Stem Cells / physiology*
  • Neurogenesis / physiology*
  • Protein Transport / physiology
  • RNA Interference
  • Time-Lapse Imaging

Substances

  • DNA Primers
  • Microtubule-Associated Proteins