CBX5 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population for loss-of-function studies of CBX5 (HP1??) in a haploid human model. This heterogeneous edited pool provides robust target-gene disruption, avoiding clonal bias and enabling consistent phenotypic analysis. The polyclonal format is ideal for high-throughput screening and diverse molecular assays.
The HAP1 cell line, derived from KBM-7 chronic myeloid leukemia cells, is a near-haploid human model valued for genetic studies. Its haploid karyotype simplifies knockout interpretation, as a single disrupted allele often yields complete loss of function. With rapid growth and maintained signaling pathways, HAP1 cells are widely used in research on cell cycle, DNA repair, and epigenetic regulation.
CBX5 (HP1??) is a heterochromatin protein that binds H3K9me3 marks deposited by SUV39H1. It recruits HDAC1, DNMT1, and lamin B receptor to promote transcriptional repression and chromatin compaction. Upstream regulators include E2F1, TP53, RB1, Aurora B, and CDK1. CBX5 interacts with SUV39H1, CHAF1A, TIF1??, and BRG1 to propagate silencing and maintain genome architecture. Downstream, it represses CDKN1A (p21), linking heterochromatin to cell cycle and DNA repair.
In HAP1 cells, CBX5 knockout disrupts constitutive heterochromatin, causing derepression of silenced genes, altered nuclear organization, and increased genome instability. This recapitulates epigenetic dysregulation observed in breast, prostate, and glioblastoma cancers, as well as aging-related heterochromatin loss. The haploid background allows clear dissection of HP1????s role in DNA damage repair and cell cycle checkpoint control, making it a valuable model for epigenetic drug target validation.
Typical applications include ChIP-qPCR for H3K9me3 profiling, RNA-seq for transcriptome analysis, and immunofluorescence or western blotting to monitor HP1?? expression and localization. DNA damage response can be assessed by ??H2AX foci quantification, and flow cytometry enables detailed cell cycle analysis. The polyclonal knockout population is suitable for investigating heterochromatin organization, epigenetic silencing, and development of cancer epigenetic therapies. For further details, contact Ascent Research.
