ATM Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population derived from the human HAP1 near-haploid myeloid cell line, featuring disruption of the ATM serine/threonine kinase gene. This polyclonal mixture provides a heterogeneous pool of loss-of-function alleles without clonal selection, offering a robust and unbiased model for investigating ATM-dependent signaling. The use of CRISPR/Cas9-mediated gene disruption ensures stable ablation of ATM expression, enabling researchers to dissect its functions in DNA damage response and genome maintenance.
HAP1 cells originate from a chronic myeloid leukemia blast crisis patient, derived from the KBM-7 line, and represent a male near-haploid model. This genetic simplification eliminates the complexity of diploid gene redundancy, greatly facilitating knockout studies and functional genomics. HAP1 retains key myeloid lineage features while offering rapid growth and ease of transfection, making it well-suited for high-throughput screening and mechanistic investigations of hematological malignancies.
ATM operates as a central kinase in DNA double-strand break (DSB) signaling. It is recruited to damage sites by the MRN complex (MRE11, RAD50, NBN) and activated via autophosphorylation at Ser1981. Activated ATM phosphorylates downstream effectors including TP53, CHEK2, BRCA1, and H2AFX (??-H2AX), orchestrating cell cycle arrest, homologous recombination, non-homologous end joining, or apoptosis. ATM also integrates oxidative stress responses and modulates PI3K/AKT and NF-??B pathways. Key interacting proteins such as ATR, DNA-PKcs, TP53BP1, MDC1, and SIRT1 further connect ATM to a broader network maintaining genomic stability.
In the HAP1 near-haploid background, ATM knockout yields a complete loss-of-function model, avoiding confounding compensation from a second allele. The polyclonal nature circumvents clone-specific artifacts, delivering a representative assessment of ATM dependency in leukemia-derived cells. This model is particularly valuable for studying radiosensitivity syndromes and cancer biology, as ATM mutations underlie ataxia-telangiectasia and confer increased risk for breast cancer, lymphomas, and leukemias.
Researchers can employ these cells for diverse functional assays: Western blotting for phospho-ATM, CHEK2, or ??-H2AX; immunofluorescence microscopy for ??-H2AX foci; comet assay for DNA damage quantitation; flow cytometry for cell cycle analysis; and clonogenic survival after ionizing radiation to assess radiosensitization. TUNEL assays detect apoptosis, while RNA-seq and phospho-kinase arrays reveal transcriptional and signaling perturbations. Applications span DNA damage response studies, cancer drug screening, and functional genomics. For further technical details and support, please contact Ascent Research.
