Journal of Neuroscience, Vol 14, 5365-5372, Copyright © 1994 by Society for Neuroscience
Oligodendrocyte precursor quantitation and localization in perinatal brain using a retrospective bioassay
GE Gonye, AE Warrington, JA DeVito and SE Pfeiffer
Department of Microbiology, University of Connecticut School of Medicine, Farmington 06030-2105.
Several late stages of the oligodendrocyte (OL) developmental lineage can
be identified immunologically in the newborn rat brain. However, OL
lineage-specific markers are not available for the detection of the less
mature, yet determined, OL precursors. We have developed a retrospective
bioassay, combining limiting dilution analysis with a novel culture system,
that quantitatively assesses the developmental potential in vivo of
phenotypically undefined OL precursors in order to (1) demonstrate their
existence, (2) estimate their total number in the premyelinated rat brain,
and (3) demonstrate their presence in regions distal to germinal zones at
times previously predicted to be devoid of such cells. Between embryonic
day (E) 21 and postnatal day (P) 0, cells determined to become
oligodendrocytes increase in frequency approximately 5-fold in the whole
brain (from one precursor for every 365 cells to 1 in 74), and
approximately 2.5-fold in the telencephalon (from 1 in 298 to 1 in 115).
From these data it is calculated that a pool of approximately 10(6)
phenotypically undefined cells are present in the newborn brain that are
able to differentiate into OL in vitro. Further, by applying this assay to
tissue samples of subdomains of the developing cerebellum, we have
demonstrated that such cells are present in large numbers as early as E20
in regions sparsely populated with cells expressing the blastic neural cell
marker ganglioside GD3, suggesting that they migrated to this position as a
pre-GD3-expressing cell. These results significantly change the predicted
ontogeny of the oligodendrocyte lineage and should fuel the ongoing search
for these early OL precursors.
Stem Cells
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