Effect of C/EBP inhibition on the growth of myeloid colonies from murine marrow.

Inhibition of C/EBPs prevents the growth of myeloid colonies from murine marrow. (A) FACS analysis of murine marrow isolated from 5-FU–treated mice either untransduced (left) or transduced (right) with MIG-KαER. Forward scatter is shown on the y-axis, and GFP expression is shown on the x-axis. Particles with fewer than 280 units of forward scatter were excluded from this analysis, as they are likely to represent cell debris. The gate set for isolation of GFP⁺ cells from the transduced marrow is also shown. Note that 19% of the transduced cells were GFP^bright and that cells with modest or low levels of GFP expression were not collected. (B) The ratio, with and without 4HT, of myeloid CFUs obtained in response to the indicated cytokines, for untransduced or transduced marrow cells, and of erythroid burst-forming units (BFU-Es) from fetal liver cells is shown for a typical experiment. G indicates G-CSF; M, M-CSF; GM, GM-CSF; IL3, IL-3; and Epo, erythropoietin and insulin. An average of 13 CFU-Gs, 130 CFU-Ms, and 23 CFU-GMs per 8 × 10³ GFP⁺-transduced cells were obtained in response to GM-CSF, in the absence of 4HT. BFU-E yields from transduced fetal liver cells averaged 96 per 4 × 10⁴transduced cells.