The E2F5 Knockout HeLa Polyclonal Cells from Ascent Research are a heterogeneous population of HeLa cells with CRISPR/Cas9-mediated disruption of the E2F5 gene. This polyclonal knockout model retains editing-site diversity, providing a robust loss-of-function system for studying E2F5 biology without clonal bias. The product is supplied as a cryopreserved vial of polyclonal knockout cells.
HeLa cells are an immortalized epithelial cell line derived from a cervical adenocarcinoma and are positive for human papillomavirus type 18 (HPV18). The viral oncoproteins E6 and E7 inactivate p53 and pRb, respectively, driving uncontrolled proliferation. This widely used cancer model is amenable to genetic manipulation and functional assays.
E2F5 is a transcriptional repressor that forms complexes with DP proteins (DP-1, DP-2) and pocket proteins p107 or p130 to bind E2F sites and inhibit cell cycle gene expression. Key downstream targets include CCNA2, CCNE1, and CDC6. Upstream, TGF-beta receptor signaling activates CDK inhibitors p21 and p27, which inhibit CDK4/6-cyclin D activity, preventing p107/p130 phosphorylation and maintaining E2F5-mediated repression. E2F5 also associates with HDAC1 to enforce a repressive chromatin state. The E2F5-DP-p107/p130 complex serves as a key effector of growth-inhibitory signals, linking TGF-beta and CDK inhibitor pathways to transcriptional silencing. In quiescent cells, this repression is critical for maintaining G0/G1 arrest. CRISPR-mediated disruption of E2F5 is predicted to relieve this repression, promoting transcription of S-phase genes.
Although pRb is degraded by HPV18 E7, p107 and p130 remain intact, enabling E2F5 to retain repressive function. Thus, E2F5 knockout in HeLa cells provides a unique opportunity to study p107/p130-mediated gene regulation in a cancer background where pRb is absent. This model is expected to enhance proliferation and facilitate investigation of TGF-beta growth-inhibitory signaling and viral oncoprotein interactions with the E2F network. It is relevant for cervical cancer research and other cancers with E2F5 dysregulation.
Applications include gene expression profiling by RT-qPCR and Western blotting, ChIP-qPCR for E2F promoter occupancy, flow cytometry for cell cycle analysis, and proliferation assays (MTS, BrdU). Reporter gene assays can measure E2F transcriptional activity. These cells also serve as a platform for chemical screening or mechanistic studies of TGF-beta/pRb signaling. For more information, please contact Ascent Research.
