The Journal of Neuroscience, April 1, 1998, 18(7):2486-2497
Bcl-2 Protein as a Marker of Neuronal Immaturity in Postnatal
Primate Brain
Patrick J.
Bernier and
André
Parent
Laboratoire de Neurobiologie, Centre de recherche Université
Laval Robert-Giffard, Beauport, Québec, Canada G1J 2G3
The distribution of neurons expressing immunoreactivity for the
protein Bcl-2 was studied in the brain of squirrel monkeys (Saimiri sciureus) of various ages. Several subsets of
small and intensely immunoreactive neurons displaying an immature
appearance were disclosed in the amygdala and piriform cortex. The
piriform cortex exhibited clusters of various forms in which Bcl-2+
neurons appeared linked to one another by their own neurites. The
subventricular zone, which is known to harbor the largest population of
rapidly and constitutively proliferating cells in the adult rat brain, was intensely stained, particularly at the basis of the lateral ventricle. A long and dorsoventrally oriented Bcl-2+ fiber fascicle was
seen to emerge from the subventricular zone, together with numerous
Bcl-2+ cells that formed a densely packed column directed at the
olfactory tubercle. In adult and aged monkeys, the small and intensely
labeled neurons were progressively replaced by larger and more weakly
stained neurons in the amygdala and piriform cortex. In contrast, Bcl-2
immunostaining did not change with age in the subventricular zone and
olfactory tubercle, the islands of Calleja of which were markedly
enriched with Bcl-2. The dentate gyrus contained only a few layers of
intensely labeled granule cells in juvenile monkeys, but the number of
these layers increased markedly in adult and aged monkeys. These
findings suggest that Bcl-2 can serve as a marker of both proliferating
and differentiating neurons and indicate that such immature neurons may
be much more widespread than previously thought in postnatal primate
brain.
Key words:
Bcl-2 protein; bcl-2 proto-oncogene; brain
maturation; neuron differentiation; aging; subventricular zone; adult
brain neurogenesis; progenitors cells
Copyright © 1998 Society for Neuroscience 0270-6474/98/1872486-12$05.00/0
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