Schematic of the human CEBPA locus. Enhancer elements upstream of the CEBPA promoter are flanked by acetylated lysine 27 on the tail of histone H3 (H3K27ac). The genomic sequence under each enhancer contains consensus transcription factor–binding sites (TFBS). In all tissues that express CEBPA, transcription factors bind their consensus sequences within the ubiquitous enhancer (ubiquitous TFBS1 and TFBS2). Lineage-specific transcription factors bind their consensus sequences within the tissue-specific enhancer only when CEBPA is expressed in the corresponding cell lineage (lineage-specific TFBS3 and TFBS4). gDNA, genomic DNA.