The BMI1 Knockout HAP1 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population in which the BMI1 gene has been disrupted in the HAP1 human near-haploid cell line. This heterogeneous pool of cells, each carrying distinct loss-of-function mutations, ablates BMI1 protein expression and provides a robust model for studying BMI1-dependent processes. The polyclonal format minimizes clonal bias and is well-suited for applications in cancer biology, epigenetics, and functional genomics.
HAP1 cells are derived from the KBM-7 chronic myeloid leukemia (CML) cell line and exhibit a near-haploid karyotype, male origin, and adherent fibroblast-like morphology. Because they carry a single copy of most chromosomes, disruption of one allele typically results in complete loss of gene function, establishing clear genotype-phenotype correlations. This haploid nature, combined with a CML disease background, renders HAP1 an optimal host for haploid genetic screens and CRISPR-based knockout studies.
BMI1 functions as a core component of Polycomb Repressive Complex 1 (PRC1), where it stimulates the E3 ubiquitin ligase activity of RING1B to catalyze monoubiquitination of histone H2A at lysine 119 (H2AK119ub). This chromatin mark leads to transcriptional silencing of critical targets including the CDKN2A locus, which encodes the tumor suppressors p16INK4a and p14ARF. By repressing CDKN2A, BMI1 inhibits Rb and p53 pathways, thereby promoting cell cycle progression and preventing senescence. BMI1 is regulated by upstream factors such as MYC, E2F, NF-??B, and Wnt/??-catenin, and interacts with PRC1 subunits like CBX proteins (CBX2,4,6,7,8) and PHC1-3 to control downstream effectors including HOX genes and PTEN.
In the HAP1 background, BMI1 knockout leads to de-repression of the CDKN2A locus, activating p16INK4a and p14ARF, which induce cell cycle arrest, senescence, or apoptosis. The haploid nature of HAP1 ensures that phenotypes are not masked by a second functional allele, making it an isogenic system to investigate BMI1’s role in leukemogenesis and its interplay with signaling cascades such as PI3K/AKT/mTOR, Hedgehog, and Wnt/??-catenin. The polyclonal population allows assessment of overall pathway effects without clonal variation.
These cells are applicable to diverse research areas: in cancer biology, they enable studies of BMI1-dependent proliferation, colony formation, and migration/invasion; for epigenetic investigations, ChIP-qPCR can measure H2AK119ub and PRC1 occupancy, while RNA-seq reveals transcriptomic changes. Senescence research can utilize ??-galactosidase staining and flow cytometry for cell cycle analysis. The polyclonal format also supports high-throughput haploid genetic screens to identify novel drug targets or genetic interactors. Researchers can confirm knockout by Western blot for BMI1 protein or RT-qPCR for mRNA. For more information, please contact Ascent Research.
