The DOT1L Knockout HAP1 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population that enables targeted disruption of the DOT1L gene in a near-haploid human cell background. This product is supplied as a heterogeneous pool of edited cells, providing a versatile loss-of-function model without clonal isolation. The polyclonal format is well suited for functional genomic screens, pathway analysis, and inhibitor profiling where population-level effects are desired.
HAP1 cells are derived from the KBM-7 chronic myeloid leukemia cell line and possess a near-haploid karyotype, making them an exceptional host for CRISPR-based knockout studies. Their haploid state simplifies genetic manipulation and interpretation, as only a single allele needs to be disrupted to achieve a functional null phenotype. This feature, combined with robust growth characteristics, has established HAP1 as a leading platform for high-throughput genetic screens and mechanistic investigations of cancer-relevant genes.
DOT1L is the sole histone-lysine N-methyltransferase that catalyzes mono-, di-, and trimethylation of histone H3 at lysine 79 (H3K79me1/2/3), a mark intimately linked to active transcription, elongation, telomeric silencing, and DNA damage responses. In the context of MLL-rearranged leukemias, DOT1L is aberrantly recruited by MLL-fusion proteins such as MLL-AF9 through direct interactions with adapter molecules AF9, AF10, and ENL. This recruitment enforces H3K79 methylation at promoters and enhancers of critical leukemogenic targets, including HOXA9, MEIS1, and c-MYC, thereby driving oncogenic transcriptional programs. Additionally, DOT1L functionally cooperates with the FACT complex (SSRP1, SUPT16H) and the phosphorylated C-terminal domain of RNA polymerase II to facilitate transcriptional elongation, and its activity is regulated by upstream cues from the WNT signaling pathway and H2B ubiquitination.
DOT1L knockout in the HAP1 near-haploid model provides a powerful system to dissect the dependence of MLL-fusion-mediated leukemogenesis on H3K79 methylation. The loss of DOT1L in this background eliminates H3K79me marks and abrogates expression of key downstream targets, offering a clean cellular context to study oncogenic addiction, epigenetic regulation, and resistance mechanisms. The model is particularly valuable for evaluating DOT1L-targeted therapeutics, as it allows precise measurement of inhibitor specificity and potency without compensatory effects from a second allele.
These cells are designed for a broad range of research applications. Investigators can use Western blotting to confirm loss of DOT1L and H3K79me modifications, RT-qPCR to quantify transcript levels of HOXA9 or MEIS1, and cell proliferation assays to assess growth dependency. Compound sensitivity profiling with DOT1L inhibitors, such as pinometostat, is readily performed, while omics approaches like RNA-seq and ChIP-seq for H3K79me2 enable genome-wide characterization of transcriptional and epigenetic changes. The polyclonal pool also supports functional genomics screening in a haploid format. For further details or technical support, please contact Ascent Research.
