AML patient blasts with p15INK4b DNA methylation display reduced H3K4me3 enrichment at the promoter. (A) Bisulfite sequencing of the p15INK4b exon 1 CpG island in AML patient samples. Filled circles represent the frequency of DNA methylation at CpG positions in sequenced clones (● represents ≥ 50% methylcytosine; , 10%-49% methylcytosine). (B) Quantitative RT-PCR analysis of p15INK4b expression in AML patient blasts. cDNA copies per 50 ng total RNA were calculated from a plasmid DNA standard curve and represent the averages of 3 independent experiments with error bars of SD. Quantitative PCR analysis (C) of H3K4me3 and H3K27me3 enrichment at the p15INK4b promoter. Data are averages of ΔΔC_t compared with input DNA from 3 technical replicates with error bars of SD. ChIP-on-chip analysis of enrichment of H3K4me3 (blue) and H3K27me3 (red) on chromosome 9: 21953000 to 22003000 (D) and chromosome 9: 21990000 to 22003000 (E) in AML patient samples. Top axis represents H3K4me3; and bottom axis, H3K27me3. Normalized enrichment data (IP/input) are plotted on a log 2 scale.