N. Minegishi et al., ERYTHROPOIETIN-DEPENDENT INDUCTION OF HEMOGLOBIN-SYNTHESIS IN A CYTOKINE-DEPENDENT CELL-LINE M-TAT, The Journal of biological chemistry, 269(44), 1994, pp. 27700-27704
M-TAT is a cytokine-dependent cell line with the potential to differen
tiate along the erythroid and megakaryocytic lineages. We cultured M-T
AT cells long term (>1 year) in the continuous presence of erythropoie
tin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF),
or stem cell factor (SCF). These long term cultures are referred to as
M-TAT/EPO, M-TAT/GM-CSF, and M-TAT/SCF cells, respectively. Hemoglobi
n concentration and gamma-globin and erythroid delta-aminolevulinate s
ynthase mRNA levels were significantly higher in M-TAT/EPO cells than
in M-TAT/GM-CSF cells. When the supplemented cytokine was switched fro
m GM-CSF to EPO, hemoglobin synthesis in M-TAT/GM-CSF cells increased
rapidly (within 5 h), and the level of GATA-1 mRNA increased. In contr
ast, the addition of GM-CSF to the M-TAT/EPO cell culture decreased th
e amount of hemoglobin, even in the presence of EPO, indicating that t
he EPO signal for erythroid differentiation is suppressed by GM-CSF. T
hus, erythroid development of M-TAT cells is promoted by EPO and suppr
essed by GM-CSF. These results support the hypothesis that EPO activel
y influences the programming of gene expression required for erythroid
progenitor cell differentiation.