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Peering into Stem Cells in Live Brain: Interdisciplinary
Approaches to Study Neural Development and Disorder
Jin-Wu Tsai1
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Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Abstract: The vertebrate central nervous system (CNS) originates from neural stem cells
composed of highly organized neuroepithelial and, subsequently, radial glial cells, which give rise
to virtually all neurons in the brain. During development, these neural stem cells and their progeny
go through a series of motile events, including migration, morphogenesis, and neurite outgrowth.
Any small perturbation in these processes can cause neural developmental disorders, such as
lissencephaly, microcephaly, double cortex, schizophrenia, and even autism. In order to study the
etiology of these developmental disorders, we established animal models to elucidate the functions
of their causal genes in vivo. For example, we used in utero electroporation of shRNA constructs
into embryonic neural stem cells to knock down the expression of LIS1, mutations of which lead
to lissencephaly.
We found that knockdown of LIS1 completely blocks the interkinetic nuclear
migration (INM), as well as the subsequent radial migration of committed neuronal precursors (J
Cell Biol, 176:935). We further developed a culture system to observe neural cells in brain slices
using high resolution light microscopy. Live imaging of coexpressed histone, centrosome, and
microtubule plus-end markers revealed that LIS1 is required for both nuclear and centrosome
movement in the radially migrating cells (Nat Neurosci, 10:970). We have also applied these
approaches to the behavior of neural stem cells and found that INM involve a cell cycle-dependent
switch between dynein- and nonconventional kinesin-driven nuclear transport (Nat Neurosci,
13:1463). We now used in vivo cerebellar eleccroporation to label and manipulate gene expression
in cerebellar granule neuron progenitors (GNPs) and investigate the molecular mechanisms of
neural stem cell proliferation, differentiation and migration during cerebellar development. These
approaches can be expanded to elucidate the mechanism of normal brain development and shed
light on how various genes cause many neural developmental disorders.
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