c-Myb and GATA-2 expression in 4-HT/siRNA-treated parental or C/EBPα-ER–expressing K562 cells. (A) Western blots show c-Myb and GATA-2 expression in 4-HT–treated wild-type C/EBPα-ER–expressing K562 cells. (B) Western blots show c-Myb or GATA-2 levels in K562 cells transfected with c-Myb or GATA-2 siRNAs. Data are representative of 3 experiments.