Histone modifications within the β-globin locus in primitive erythroblasts from mice harboring deletions of the ϵy- and/or βh1-globin gene promoters. Histone modification patterns and mRNA expression levels were analyzed in E12.5 peripheral blood from mice homozygous for the deletion of either one (Δϵy Pr. and Δβh1 Pr.) or both (Δϵy/Δβh1 Pr.) of the embryonic globin gene promoters. (A) Schematic of the β-globin locus showing a closer view of the regions being analyzed and the location of each deletion. (B) Globin expression levels using quantitative RT-PCR. Values are standardized to 18S mRNA levels and are presented as the fold change with respect to the levels seen in wild-type mice. (C) Enrichments for H3Ac (top) and H3K4 dimethyl (bottom) at the indicated locations within the β-globin locus in E12.5 blood from the indicated embryonic promoter deletion mice.