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ISDN2012_0246: Development of V2 and V0 neurons in zebrafish spinal cord
Author(s) -
Higashijima Shinichi
Publication year - 2012
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/j.ijdevneu.2012.10.075
Subject(s) - zebrafish , spinal cord , citation , library science , neuroscience , computer science , medicine , psychology , biology , gene , biochemistry
Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, United States Recent insights gained from studies of the developing cerebral cortex are illuminating potential evolutionary steps that contributed to structural and functional features of the human brain. Radial glial cells (RG), long thought to simply guide embryonic nerve cells during migration, have now been identified as neuronal stem cells in the developing brain. RG cells undergo self-renewing, asymmetric divisions to generate neuronal precursors that can further proliferate in the subventricular zone (SVZ) to increase neuronal number. Unlike the developing rodent cortex, the developing human cortex contains a massively expanded SVZ (OSVZ) that is thought to account for the bulk of cortical neurogenesis. We have begun to characterize the types and locations of progenitor cells responsible for human cortical development. We found that large numbers of radial glia-like cells and intermediate progenitor cells populate the human OSVZ. The OSVZ radial glia-like cells have a long basal process but, surprisingly, do not have basolateral polarity and lack contact with the ventricular surface. Using real-time imaging and clonal analysis, we demonstrate that these cells undergo self-renewing asymmetric divisions to generate neuronal progenitor cells that can further proliferate. We have recently found that progenitor cells resembling oRG cells are present in mouse embryonic neocortex, and arise from asymmetric divisions of radial glia. Time-lapse imaging reveals that the cells undergo self-renewing asymmetric divisions to generate neurons. These results suggest that oRG cells are probably present in all mammals and are not a specialization of a larger brain with increased cortical area. Instead, an evolutionary increase in the number of oRG cells and their transit amplifying daughter cells likely amplified neuronal production and contributed to increased cortical size and complexity in the human brain.