DNA methylation profiling in acute myeloid leukemia

We analyzed levels of 5-methyl cytosine CCCGGG target sites by sequential restriction digest by SmaI and XmaI enzymes, ligating Illumina adaptors to the restriction fragments and reading methylation-specific signatures at the ends of restriction fragments by paired ends Illumina high throughput sequencing. Digital restriction enzyme analysis of methylation (DREAM) was performed to determine the methylation profile of human genomic DNA from the bne marrow of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Genomic DNA spiked in with unmethylated, partially methylated and fully methylated standards was sequentially cut at CCCGGG sites with the methylation-sensitive enzyme SmaI (blunt ends) and its methylation-tolerant neoschizomer XmaI (5'CCGG overhangs), creating different end sequences that represented methylation status of the CCCGGG sites. These end sequences were analyzed by Illumina high throughput sequencing. Methylation status at individual CCCGGG sites across the genome was determined by counting the methylated reads with the CCGGG signature and unmethylated reads with the GGG signature at the beginnings of the sequencing reads after alignment to the human genome. Raw data are unavailable for GSM2188184-GSM2188189 and GSM2188193-GSM2188214 due to data loss.