Regulation of gene expression in MEL cells by C/EBPα. (A) MEL cells and αER-E4 clone cells were treated with 3 mM HMBA and 1.0 μM β-estradiol. Total cell lysates were prepared from treated cells at the indicated times and 30 μg was analyzed for GATA-1, PU.1, and α-actin expression by Western blot analysis as described in “Materials and methods.” (B) Total RNA was also obtained from MEL cell clones 10 hours after treatment with HMBA and β-estradiol. Expression of the indicated genes was evaluated by RT-PCR using the indicated cycle numbers (24, 26, 28, and 30 cycles for β-globin, or 26, 28, 30, and 32 cycles for all other genes). The line graph represents densitometry scan of each band on an agarose gel.