Characterization of nuclear factors that bind to a critical positive
regulatory element of the human granulocyte-macrophage colony- stimulating
factor promoter
JK Fraser, S Tran, SD Nimer and JC Gasson
Department of Medicine, UCLA.
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a
hematopoietic growth factor that stimulates the proliferation, maturation,
and functional activity of myeloid cells in peripheral blood and bone
marrow. Expression of GM-CSF is tightly regulated and is limited to cells
stimulated directly (T cells, macrophages) or indirectly (fibroblasts,
endothelial cells) by immune challenge. Several studies of the
transcriptional control of GM-CSF expression have elucidated a region of
the GM-CSF promoter that mediates positive regulatory activity in a number
of cell types. This region contains a direct repeat of the sequence CATTA/T
that extends from nucleotides -37 to -48 upstream of the start of mRNA
synthesis. Although specific DNA:protein interactions have been shown
within this region, neither the nature nor the number of nuclear factors
responsible for these interactions have been characterized. In this study,
we use DNase I footprinting analysis to demonstrate that point mutations,
which inactivate the GM-CSF promoter, disrupt DNA:protein interactions
within this region. By combined electrophoretic mobility shift and
ultraviolet cross-linking analysis, we have detected several protein
species that bind specifically to the positive regulatory sequence.
Volume 84,
Issue 8,
pp. 2523-2530,
10/15/1994
Copyright © 1994 by The American Society of Hematology
