The Journal of Neuroscience, June 1, 2001, 21(11):3780-3787
A Distal Upstream Enhancer from the Myelin Basic
Protein Gene Regulates Expression in Myelin-Forming
Schwann Cells
Reza
Forghani,
Lorella
Garofalo,
David R.
Foran,
Hooman F.
Farhadi,
Pierre
Lepage,
Thomas J.
Hudson,
Irene
Tretjakoff,
Priscila
Valera, and
Alan
Peterson
Laboratory of Developmental Biology, Department of Neurology and
Neurosurgery, Molecular Oncology Group H-5, McGill University,
Montreal, Quebec, Canada, H3A 1A1
In peripheral nerves, large caliber axons are ensheathed by
myelin-elaborating Schwann cells. Multiple lines of evidence
demonstrate that expression of the genes encoding myelin structural
proteins occurs in Schwann cells in response to axonal instructions. To gain further insight into the mechanisms controlling myelin gene expression, we used reporter constructs in transgenic mice to search
for the DNA elements that regulate the myelin basic
protein (MBP) gene. Through this in
vivo investigation, we provide evidence for the
participation of multiple, widely distributed, positive and
negative elements in the overall control of MBP
expression. Notably, all constructs bearing a 0.6 kb far-upstream
sequence, designated Schwann cell enhancer 1 (SCE1), expressed at high
levels in myelin-forming Schwann cells. In addition, robust targeting activity conferred by SCE1 was shown to be independent of other MBP 5' flanking sequence. These observations suggest
that SCE1 will make available a powerful tool to drive transgene
expression in myelinating Schwann cells and that a focused analysis of
the SCE1 sequence will lead to the identification of transcription factor binding sites that positively regulate MBP expression.
Key words:
myelin basic protein; Schwann cells; myelination; MBP
regulation; MBP regulated transgenes; sensory and motor fibers; Krox-20
Copyright © 2001 Society for Neuroscience 0270-6474/01/21113780-08$05.00/0