The ASF1A Knockout HAP1 Polyclonal Cells product is a CRISPR/Cas9-edited polyclonal cell population with targeted disruption of the ASF1A gene in a HAP1 background. This model provides a heterogeneous pool of HAP1 cells carrying diverse loss-of-function alleles, enabling robust functional studies of ASF1A without the biases associated with clonal selection. It serves as a versatile tool for analyzing chromatin assembly, replication stress, and the DNA damage response in a near-haploid cellular context.
HAP1 is a human near-haploid cell line derived from the KBM-7 chronic myeloid leukemia line. Its predominantly haploid karyotype simplifies genetic analysis and enhances the phenotypic penetrance of CRISPR-induced mutations, making it a preferred host for functional genomics and drug discovery. The HAP1 cell line maintains stable growth characteristics and retains key signaling pathways relevant to cancer biology, offering a reproducible platform for mechanistic investigation.
ASF1A encodes a conserved histone chaperone that mediates the delivery of histone H3?CH4 dimers to nascent chromatin. Upstream, ASF1A transcription is driven by E2F1, while its activity is modulated by ATM/ATR kinases in response to DNA damage. ASF1A physically interacts with CHAF1B and HIRA to hand off histones to the CAF-1 and HIRA complexes, respectively, directing both replication-coupled and replication-independent nucleosome assembly. Through these interactions, ASF1A coordinates DNA replication, transcription, and repair with chromatin maintenance. Disruption of ASF1A therefore impedes proper chromatin formation, leading to replication stress, accumulation of DNA lesions, and genome instability.
In the HAP1 cell environment, ASF1A knockout is predicted to severely impair chromatin assembly, resulting in spontaneous DNA damage evident by elevated ??H2AX levels and cell cycle delays. The haploid genotype sensitizes cells to replication-defect phenotypes, allowing clear readouts in proliferation and drug sensitivity assays. This polyclonal knockout pool is particularly advantageous for high-throughput screens, as the population heterogeneity mirrors the complexity of tumor cell responses and can reveal synthetic lethal relationships unobservable in single clones.
Typical research applications include functional validation of ASF1A as a cancer drug target, epigenetic studies using ChIP-qPCR to assess histone incorporation at specific loci, and DNA damage response profiling by ??H2AX immunofluorescence or flow cytometry. The model also supports RNA-seq analyses of transcriptional consequences and combinatorial drug screening to identify vulnerabilities associated with replication stress. For further technical details or application support, please contact Ascent Research.
