Asymmetric production of surface-dividing and non-surface-dividing cortical progenitor cells
Development, 131 (13):
3133--3145 (2004)DOI: 10.1242/dev.01173
Abstract
Mature neocortical layers all derive from the cortical plate (CP), a
transient zone in the dorsal telencephalon into which young neurons are
continuously delivered. To understand cytogenetic and histogenetic events that
trigger the emergence of the CP, we have used a slice culture technique. Most
divisions at the ventricular surface generated paired cycling daughters (P/P
divisions) and the majority of the P/P divisions were asymmetric in daughter
cell behavior; they frequently sent one daughter cell to a non-surface (NS)
position, the subventricular zone (SVZ), within a single cell-cycle length
while keeping the other mitotic daughter for division at the surface. The
NS-dividing cells were mostly Hu+ and their daughters were also
Hu+, suggesting their commitment to the neuronal lineage and supply
of early neurons at a position much closer to their destiny than from the
ventricular surface. The release of a cycling daughter cell to SVZ was
achieved by collapse of the ventricular process of the cell, followed by its
NS division. Neurogenin2 (Ngn2) was immunohistochemically detected in a
certain cycling population during G1 phase and was further restricted during
G2-M phases to the SVZ-directed population. Its retroviral introduction
converted surface divisions to NS divisions. The asymmetric P/P division may
therefore contribute to efficient neuron/progenitor segregation required for
CP initiation through cell cycle-dependent and lineage-restricted expression
of Ngn2.
Description
Asymmetric production of surface-dividing and non-surface-dividing cortical progenitor cells