Journal of Neuroscience, Vol 5, 2955-2962, Copyright © 1985 by Society for Neuroscience
The timely expression of myelin basic protein gene in cultured rat brain oligodendrocytes is independent of continuous neuronal influences
NK Zeller, TN Behar, ME Dubois-Dalcq and RA Lazzarini
The developmental expression of the myelin basic protein (MBP) gene was
studied in rat cultured oligodendrocytes using immunofluorescence and in
situ hybridization. In newborn rat brain cultures, which contain only glial
cells, large amounts of MBP-specific mRNA (as assayed by grain counts in
autoradiograms) abruptly accumulated within immature oligodendrocytes 5 to
6 days postnatal. MBP always emerged 6 to 8 days after birth; thus, a week
after, galactocerebroside (GC), an early oligodendrocyte marker, had
appeared. The percentage of MBP mRNA and MBP-positive cells peaked at about
15 days postnatal and decreased thereafter. The time of emergence of MBP in
these cultured oligodendrocytes appears to be determined at a very early
stage in their development and independent of continuous neuronal
influences. There is a striking correspondence between the times of
appearance of MBP in cultured oligodendrocytes and those in the intact
animal. Thus, primary cultures made from 5-day prenatal, newborn, and 2-day
postnatal animals all express MBP at about the same developmental stage,
namely, after 14, 8, and 6 days in culture, respectively. Furthermore,
cultured oligodendrocytes obtained from the spinal cord express MBP before
those obtained from midbrain or hemispheres, as they would in the intact
animal. Thus, the developmental expression of the MBP gene occurs in a
similar time frame in vitro and in vivo. In oligodendrocyte-enriched
cultures, where 60% to 80% of the cells express MBP, in situ hybridization
with the cDNA clone revealed MBP-specific mRNA in the cell body and
sometimes in the processes of the differentiated oligodendrocytes.(ABSTRACT
TRUNCATED AT 250 WORDS)
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