Relative expression of β-globin and γ-globin mRNA in human primary erythroid cells. (A) Globin mRNA analysis by RT-PCR. Cord blood erythroid progenitors were cultured either in control conditions, in the presence of AB (100 μM), or in the presence of RB7 (20 μM), and globin expression was assayed by RT-PCR. Values represent an average of 3 experiments, from independent cord blood specimens; error bars represent the standard errors of the mean. An increase in γ-globin mRNA, and corresponding decrease in the β-globin mRNA, was observed with SCFAD treatment compared with untreated controls. (B) Chromatin immunoprecipitation and quantitative PCR at the endogenous γ-globin gene promoter. Relative association of HDAC3 and RNA polymerase II at the γ-globin gene promoter in cord blood erythroid progenitors determined under control conditions, or with RB7 or AB treatment; error bars represent the standard errors of the mean. (C) Agarose gel showing relative association of HDAC3 and RNA polymerase II with the γ-globin promoter in cord blood erythroid progenitors cultured in either control conditions, AB (100 μM), or RB7 (20 μM). Results are representative of 3 independent experiments.