Profiles of globin gene expression and histone H3 acetylation in fetal and adult erythroblasts. The expression profiles of the human globin genes (A-C) were measured by RNase protections assays. Total RNA was prepared from several fetal liver samples and adult erythroblasts as well as K562 cells. Probes for RNase protections were human α-globin, ε-globin, γ-globin, and human β-globin samples were 105d FL (A), adult erythroblasts (B), and K562 (C). The amount of RNA used in each reaction is shown at the top of the panels. Quantification was carried out using a PhosphorImager (GE Healthcare, Chalfont St. Giles, United Kingdom). Histone acetylation profiles within the β-globin locus are shown in D (fetal stage) and E (adult stage). Each data point represents enrichment of crosslinked chromatin immunoprecipitated using antibodies against histone H3 acetylation. The y-axis values measure relative enrichments relative to the endogenous amylase gene. The results of 3 to 9 experiments are shown (± SEM). The x-axis is the coordinate of the human β-globin locus with the cap site of the ε-globin gene being set at 1. The human β-globin locus is represented above the graphs. Open box, ε-globin gene; gray boxes, ^Gγ- and ^Aγ-globin genes; closed boxes, δ- and β-globin genes; striped boxes, olfactory receptor genes. Gray arrowheads on the x-axis mark the positions of the globin gene promoters. Vertical arrows indicate DNase I hypersensitive sites.