Control of Cortical Neuron Layering: Lessons from Mouse Chimeras

  1. Gregory Bock Organizer and
  2. Jamie Goode
  1. Vicki Hammond,
  2. Joanne Britto,
  3. Eva So,
  4. Holly Cate and
  5. Seong-Seng Tan

Published Online: 1 FEB 2008

DOI: 10.1002/9780470994030.ch8

Cortical Development: Genes and Genetic Abnormalities: Novartis Foundation Symposium 288

Cortical Development: Genes and Genetic Abnormalities: Novartis Foundation Symposium 288

How to Cite

Hammond, V., Britto, J., So, E., Cate, H. and Tan, S.-S. (2008) Control of Cortical Neuron Layering: Lessons from Mouse Chimeras, in Cortical Development: Genes and Genetic Abnormalities: Novartis Foundation Symposium 288 (eds G. Bock and J. Goode), John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470994030.ch8

Author Information

  1. Howard Florey Institute, Cnr. Royal Parade and Grattan Street, University of Melbourne, Parkville VIC 3010, Australia

Publication History

  1. Published Online: 1 FEB 2008
  2. Published Print: 11 JAN 2008

Book Series:

  1. Novartis Foundation Symposia

Book Series Editors:

  1. Novartis Foundation

ISBN Information

Print ISBN: 9780470060926

Online ISBN: 9780470994030

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Keywords:

  • reelin;
  • disabled-1;
  • p35;
  • cortical layering;
  • projection neurons;
  • cortical interneurons

Summary

How is the activation of Reelin signalling within neurons translated into the layering of cortical neurons? To address this question, we made mouse chimeras to test the reciprocal effects of neurons possessing different genotypes but sharing a common cortical environment during development. In chimeras composed of wild-type and mutant neurons (for either Reelin, Dab1 or p35 genes), a common observation was the formation of a second set of cortical layers on top of an inverted mutant cortex. The secondary cortex was invariably layered in the correct order, and in Dab1 and p35 chimeras, they were principally composed of wild-type neurons. In contrast to these cellautonomous effects, Reelin chimeras displayed non cell-autonomous effects. In these chimeras, only a small number of wild-type neurons were required to be present in order for a secondary cortex to be formed. Interestingly, the principal constituents of the secondary cortex are not wild-type but mutant neurons, suggesting non cell-autonomous signalling by low levels of Reelin. Overall, these results suggest that information for the generation of cortical layers is vested within neuroepithelial progenitors even before the first neurons have been born, but the guidance of successive generations of daughter neurons to their proper locations requires the activation of Reelin and p35.