The CBX5 Knockout 786-O Polyclonal Cells product comprises a heterogeneous population of CRISPR/Cas9-edited 786-O renal carcinoma cells with targeted disruption of the CBX5 gene, encoding the heterochromatin protein 1 alpha (HP1??). This polyclonal knockout pool preserves the genetic diversity inherent to a mixed population of edited cells, enabling robust functional studies without clonal artifacts. The product serves as a loss-of-function model for investigating HP1??-mediated chromatin regulation, transcriptional silencing, and tumor-suppressive or oncogenic roles in a clear cell renal cell carcinoma (ccRCC) background.
The host 786-O cell line is a widely used model of ccRCC, derived from a primary renal cell adenocarcinoma of a male patient. These cells are VHL-null, leading to constitutive stabilization of hypoxia-inducible factors (HIFs) and activation of downstream pathways that mimic a pseudohypoxic state. Additionally, 786-O cells express wild-type p53 and retain characteristics of renal proximal tubule epithelial cells, making them particularly suitable for studying epigenetic mechanisms that intersect with HIF signaling, metabolic reprogramming, and tumor progression.
CBX5 functions as a reader of trimethylated histone H3 at lysine 9 (H3K9me3), a hallmark of constitutive heterochromatin, and mediates chromatin compaction and gene silencing. Its activity is tightly regulated by upstream kinases such as CDK1, Aurora B, and PKA, and it interacts with key epigenetic modifiers including the methyltransferases SETDB1 and SUV39H1, the scaffolding protein KAP1 (TRIM28), and the Lamin B receptor. CBX5 forms complexes with CAF-1 and the FACT complex, contributing to replication-coupled chromatin assembly. Through these interactions, HP1?? represses transcription of E2F target genes, cyclin D1, and survivin, while its loss can derepress cell cycle inhibitors like p21 (CDKN1A). Furthermore, CBX5 participates in DNA damage signaling via Chk2 and BRCA1, linking epigenetic regulation to genomic stability.
In the VHL-null 786-O context, CBX5 knockout is particularly relevant because HP1?? has been implicated in modulating HIF-1?? transcriptional activity and the cellular response to hypoxia. Epigenetic silencing mediated by HP1?? can influence expression of angiogenic factors, metabolic enzymes, and epithelial-mesenchymal transition markers, thereby affecting tumor growth, invasion, and senescence. Disruption of CBX5 in these cells provides a powerful tool to dissect how H3K9me3-dependent heterochromatin dynamics contribute to ccRCC pathogenesis and to the altered signaling networks driven by VHL loss.
Researchers can employ this polyclonal knockout model in a variety of experimental workflows, including chromatin immunoprecipitation (ChIP) to assess H3K9me3 enrichment, co-immunoprecipitation to map HP1?? interaction partners, and immunofluorescence to monitor heterochromatin organization. Proliferation, apoptosis, and wound healing assays can be used to read out functional consequences, while transcriptomic (RNA-seq) and proteomic analyses enable unbiased pathway discovery. This product is ideal for high-throughput screening of epigenetic drugs and for mechanistic studies of HP1?? in ccRCC. For custom requests or additional technical specifications, please contact Ascent Research.
