The +42-kb region is specifically H3K27ac marked in CD34⁺ HSCs. (A) CEBPA mRNA expression determined by qPCR in FACS-sorted populations of normal CD34⁺ bone marrow cells, metamyelocytes, and neutrophils (n = 3). (B) H3K27ac ChIP-seq in CD34⁺ cells, obtained from GCSF-mobilized peripheral blood cells, reveals enrichment at the +9-kb and +42-kb enhancers. Motifs that correspond to specific TF-binding sites are depicted underneath each enhancer (for details, see supplemental Figure 3A). (C) ChIP-seq for the indicated transcription factors carried out in CD34⁺ cells shows specific binding at the +42-kb enhancer. (D) ChIP-seq for p300 in MOLM-1 CEBPA⁺ cell line MOLM-1 reveals the strongest interaction at +42 kb. (E) ChIP-qPCR shows p300 enrichment within the +42-kb region in the CEBPA-expressing cell lines MOLM-1, U937, HL-60, THP-1, but not in the CEBPA⁻ hematopoietic cell lines Jurkat and Raji, CEBPA⁺ lung cell line H292, and CEBPA⁻ cervical cell line HeLa. Enrichment was calculated as fold change relative to IgG control.