Nuclear protein expression of reprogrammed transcription factors. Validation of gene expression profiles obtained by microarray and quantitative PCR analysis in low-HbF (L) and high-HbF (H) culture conditions by Western analysis. Nuclear protein extracts were used from erythroblasts grown in low-HbF versus high-HbF conditions for 7 days in 3 separate donor-matched cultures. (A) Eight transcription factors with confirmed expression changes in the nuclear protein extracts. (B) Three transcription factors with reprogramming demonstrated by RNA transcript levels that were not confirmed in the nuclear protein extracts. GATA-1 and β-actin controls are provided for comparison (bottom).