Effect of ectopic c-Myb or GATA-2 expression on C/EBPα-dependent proliferation inhibition of K562 cells. (A) Cell counts of untreated and 4-HT–treated K562-C/EBPα-ER and Δ(358-452) c-Myb/K562-C/EBPα-ER cells. (B) Cell counts of untreated and 4-HT–treated C/EBPα-ER and GATA-2/K562-C/EBPα-ER cells. Mean plus SD (3 different experiments performed in triplicate).