SAR and γ-globin gene expression in SAR transfectants, K562 cells treated with globin inducers, and AC133⁺ cells. (A) Correlation of γ-globin and SAR mRNA. The diagonal line shows trend line. γ-globin (Gamma) and SAR mRNA levels were normalized to glycophorin C determined by quantitative RT-PCR in SAR-transfected K562 cells. (B) Northern blot analysis of γ-globin and SAR mRNA expression in K562 cells 48 hours after treatment with HU, butyrate, or 5-azacytidine, as detailed in “Materials and methods.” GAPDH was used as an internal control. (C) Quantitative analysis of γ-globin and SAR mRNA levels normalized to GAPDH from Northern blots. (D) RT-PCR determination of SAR and γ-globin mRNA expression (normalized to GAPDH) in AC133⁺ cells (with EPO) cultured for the indicated amounts of time. Error bars indicate standard deviation of the mean of 3 independent experiments.