The HLTF Knockout HAP1 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the target gene in the HAP1 human near-haploid cell line. This product provides a loss-of-function model of HLTF, the helicase-like transcription factor that functions as a DNA translocase and E3 ubiquitin-protein ligase. The polyclonal format represents a heterogeneous pool of edited cells, circumventing clonal selection while enabling robust population-level functional studies. The knockout model is suitable for investigating HLTF-dependent DNA damage tolerance, replication stress responses, and chromatin remodeling processes in a genetically defined cellular background.
The HAP1 cell line is a near-haploid derivative of the KBM-7 chronic myeloid leukemia line, widely used for CRISPR-based functional genomics and genetic screens. Its haploid karyotype simplifies the generation of complete gene disruptions and reduces genetic redundancy, making it an ideal host for interrogating loss-of-function phenotypes. HAP1 cells retain key signaling pathways relevant to leukemia biology while offering experimental tractability for high-throughput applications. In this context, HLTF disruption allows direct assessment of the protein??s role in maintaining genomic stability without the confounding effects of diploidy.
HLTF is a central effector in the DNA damage response, coordinating fork reversal and post-replication repair to preserve replication fidelity. Upon replication stress, HLTF is activated by ATR-mediated signaling and is recruited to stalled forks, where its ATP-dependent translocase activity drives fork reversal. Additionally, its RING domain catalyzes K63-linked polyubiquitination of PCNA, a modification facilitated by the E2 enzyme UBE2N (UBC13). This event promotes template switching and error-free lesion bypass. HLTF functionally interacts with RAD51 to facilitate strand exchange downstream of fork reversal and cooperates with PARP1 in sensing replication stress. It is also implicated in SWI/SNF-dependent chromatin remodeling and is regulated by E2F transcription factors and CDK2, linking cell cycle cues to genome maintenance.
In HAP1 cells, HLTF knockout serves as a powerful tool to dissect replication stress signaling and DNA repair networks in a leukemia-relevant context. Because HAP1 originates from a chronic myeloid leukemia lineage, HLTF deficiency may model aspects of tumor-associated genomic instability and hypersensitivity to chemotherapeutic agents. The knockout is expected to impair PCNA polyubiquitination and RAD51 loading at stalled forks, leading to accumulation of unrepaired DNA damage and replication fork collapse. Researchers can exploit this model to evaluate synthetic lethal interactions, assess small-molecule inhibitors targeting ATR or PARP1, and investigate the role of HLTF in leukemia cell survival and drug resistance mechanisms.
This polyclonal HLTF knockout cell product is well-suited for a range of advanced applications, including Western blotting for HLTF and ??H2AX to confirm protein loss and DNA damage induction, immunofluorescence detection of RAD51 foci as a readout of homologous recombination, DNA fiber assays to examine replication fork dynamics, and clonogenic survival assays to quantify cellular sensitivity to genotoxins. Co-immunoprecipitation experiments can probe HLTF??s interactions with PCNA, RAD51, and UBE2N. The model is particularly valuable for CRISPR functional genomics screens, cancer cell biology studies, and drug target discovery programs focused on DNA repair pathways. For further information, please contact Ascent Research.
