Regulation of the gene for CD34, a human hematopoietic stem cell antigen,
in KG-1 cells
AB Satterthwaite, R Borson and DG Tenen
Program in Cell and Developmental Biology, Harvard Medical School, Boston,
MA.
CD34 is one of the best characterized human hematopoietic stem cell
antigens defined to date. It is expressed on 1% to 4% of normal bone marrow
cells, including colony forming units of all lineages and their precursors.
CD34 expression is lost during hematopoietic development and is not found
on mature peripheral blood cells. The control of CD34 expression was
studied in the myeloblast cell line KG-1 as a model for the regulation of
stem cell genes. CD34 mRNA was expressed at high levels in uninduced KG-1
cells. Upon induction of the cells towards macrophages with
tetradecanoylphorbol-13-acetate (TPA) and ionomycin, steady state levels of
CD34 mRNA decreased rapidly. Nuclear run-on assays did not show a
significant change in the rate of CD34 transcription upon induction. The
half-life of CD34 mRNA was 4.5 hours in uninduced KG-1 cells and 2.25 hours
in induced cells, demonstrating the involvement of post-transcriptional
mechanisms in CD34 downregulation. Cycloheximide had no effect on the
downregulation of CD34, suggesting that labile proteins are not required
for this process. This model should allow the study of some of the
regulatory mechanisms controlling early events in hematopoiesis.
Volume 75,
Issue 12,
pp. 2299-2304,
06/15/1990
Copyright © 1990 by The American Society of Hematology
