Increasing H3K79me2 decreases the differential between KMT2A-MLLT3 targets and nontarget genes. Effect of directly increasing H3K79 methylation through overexpression of DOT1L on H3K79me2 profiles and the expression of KMT2A target genes in murine KMT2A-MLLT3 AML cells. Fully transformed AML cells isolated from moribund mice transplanted with KMT2A-MLLT3–transduced LSK cells were transduced with DOT1L or DOT1L-DN (control). Cells were sorted into high- and moderate-overexpressing compartments and analyzed 4 days after transduction. The sort strategy is shown in supplemental Figure 5A. Results are shown for high overexpression of DOT1L or DOT1L-DN; results for high- and moderate-overexpressing compartments are shown in supplemental Figure 5A. ChIP-seq signal height and position relative to the transcription start site (TSS) are shown for known KMT2A-MLLT3 target genes or matched nontarget genes. High overexpression of DOT1L-DN (A), NT cells (B), and DOT1L (C). GSEA plots showing negative enrichment of genes bound to the KMT2A-F¹  in samples with overexpressed DOT1L-DN (D) or DOT1L (E). GSEA plots showing that genes downregulated upon DOT1L deletion¹  are negatively enriched when DOT1L-DN (F) or DOTIL (G) is overexpressed. DN, dominant negative.