Dexamethasone promotes erythroid differentiation in cells expressing control and RPS19 shRNAs. (A) Human CD34⁺ cells expressing control (luc) or RPS19 shRNAs were grown in the presence or absence of dexamethasone (dex), and mean Gly-A expression was measured by flow cytometry. Fold induction by dexamethasone is shown as the mean and SEM. (B) Human CD34⁺ cells expressing control and RP19 shRNAs were grown with or without dexamethasone for 3 days and then plated on methylcellulose. The number of BFU-E colonies is shown as the mean and SEM. (C) CFU-GM colonies from the same cultures as panel B are shown as the mean and SEM. (D) HEL cells expressing the control (luc) or RPS19-R1 shRNA cultured in the presence (-) or absence (—) of dexamethasone were counted by hematocytometer and replated at a constant density.