Dose-response effects of 5-azacytidine during in vitro erythroid differentiation. Effects of different doses of 5-azacytidine on (A) γ-globin gene expression during differentiation, (B) β-globin gene expression during differentiation, (C) total γ- and β-globin gene expression, expressed as the area under the curve (AUC) for each dose, (D) γ/γ plus βAUC for each dose, (E) cell expansion, (F) differentiation kinetics as assessed by CD235a (glycophorin A) cell surface expression, (G) the proportion of cells in the G1 phase of the cell cycle, and (H) the proportion of cells in the S phase of the cell cycle. CD34⁺ cells were from different normal donors were used for experiments in panels A-F and G,H. Each RT-PCR analysis was performed in triplicate. Error bars represent 1 SD.