HoxA9-ER directly represses <i>Cebpa</i> gene expression in myeloid cells.

A) Total cellular proteins from parental 32Dcl3 cells, pooled 32Dcl3 MIPuro cells, and twelve 32Dcl3 MIPuro-HoxA9-ER subclones were subjected to Western blotting using anti-rabbit ERα anti-serum, followed by stripping the blot and reprobing with β-actin antibody. B) Total cellular RNAs from these cells prepared after 0, 4, or 8 hr of culture in IMDM/HI-FBS/IL-3 media alone, with 200 nM 4-hydroxytamoxifen (4HT), with 50 μg/mL cycloheximide (CHX), or with both were subjected to quantitative PCR analysis for Cebpa expression relative to mS16 mRNA. CHX was added 30 min prior to 4HT when combined (mean and SD from three independent experiments).