The CBX4 Knockout HeLa Polyclonal Cells product is a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HeLa human cervical adenocarcinoma cell line, featuring targeted disruption of the CBX4 gene. This polyclonal knockout model provides a powerful tool for loss-of-function studies of CBX4 in an epithelial cellular context. The edited population is suitable for a broad range of functional genomics and mechanistic investigations without clonal isolation, preserving genetic heterogeneity while eliminating CBX4 expression.
HeLa cells are a widely used model in cancer biology, originally established from a human cervical adenocarcinoma and positive for human papillomavirus type 18 (HPV18). These adherent epithelial cells exhibit robust proliferation and are permissive to a variety of experimental manipulations, making them a workhorse for studying oncogenic signaling, drug response, and gene function. The HPV18-positive background further offers a pathophysiologically relevant setting for exploring interactions between viral oncoproteins and host epigenetic regulators.
CBX4, or chromobox homolog 4, is a core component of the Polycomb repressive complex 1 (PRC1) and a SUMO E3 ligase. Its chromodomain directs binding to trimethylated histone H3 at lysine 27 (H3K27me3), a hallmark of Polycomb-mediated gene silencing. Within PRC1, CBX4 interacts with RING1A/B, BMI1, and PHC family members to compact chromatin and maintain transcriptional repression. Additionally, CBX4 catalyzes SUMO conjugation onto substrates including CtBP, DNMT3a, and HIPK2, modulating their functions and subcellular localization. CBX4 activity is regulated by PRC2-deposited H3K27me3 and by signals from Notch and Wnt pathways, and it governs downstream targets such as HOX gene clusters and the tumor suppressors CDKN2A and CDKN1A, thereby influencing cell cycle progression, senescence, and differentiation.
In the HeLa adenocarcinoma model, loss of CBX4 disrupts PRC1-mediated silencing and SUMOylation-dependent regulatory networks, providing a unique system to dissect their contributions to cancer cell proliferation, survival, and invasiveness. Given CBX4’s implication in cervical, breast, hepatocellular, and glioblastoma malignancies, this model enables comparative studies and may reveal conserved dependencies. The HPV18-positive background also allows investigation of cross-talk between viral E6/E7 oncoproteins and Polycomb silencing, potentially informing novel therapeutic strategies.
This polyclonal knockout cell population supports a wide range of experimental assays: Western blotting for CBX4, H3K27me3, and sumoylated species; RT-qPCR for downstream effector genes; chromatin immunoprecipitation to assess H3K27me3 occupancy and CBX4 binding; immunofluorescence for nuclear foci; flow cytometry for cell cycle and apoptosis; senescence-associated ??-galactosidase staining; and migration/invasion assays. Co-immunoprecipitation and SUMOylation assays enable detailed analysis of CBX4-containing complexes and enzymatic activity. This product is ideal for epigenetic, cancer, and SUMO biology researchers. For further information, please contact Ascent Research.
