APEX2 Knockout HEK293T Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the widely used HEK293T host cell line, featuring targeted disruption of the APEX2 gene. This loss-of-function model is designed to facilitate investigations into the biological roles of APEX2, a Class II apurinic/apyrimidinic endonuclease critical for base excision repair (BER) and maintenance of genomic stability. As a polyclonal knockout product, this population comprises a heterogeneous mix of edited cells, each carrying distinct CRISPR-mediated modifications, enabling functional studies without the selective pressure of clonal derivation.
The host cell line, HEK293T, originates from human embryonic kidney 293 cells and has been immortalized and adapted for high-efficiency protein expression and lentiviral production. Derived from HEK293 by stable transfection with the SV40 large T antigen, and with a background of adenovirus 5 DNA transformation, HEK293T cells provide a robust, well-characterized platform for dissecting molecular pathways. Their rapid proliferation, ease of transfection, and genetic tractability make them a preferred model for cancer biology, DNA damage signaling, and functional genomics.
APEX2 encodes a backup AP endonuclease that functions in the BER pathway, cleaving the phosphodiester backbone immediately 5?? to abasic (AP) sites to generate a 3??-hydroxyl terminus for DNA polymerase activity. APEX2 activity is regulated upstream by DNA damage, p53, ATM/ATR kinases, and hydrogen peroxide, and it acts in concert with downstream effectors including POLB, LIG3, and XRCC1. It directly interacts with XRCC1, POLB, LIG3, PCNA, and AP site-containing DNA, and is part of a repair complex also involving FEN1 and the primary AP endonuclease APE1. This protein network coordinates single-strand break repair and maintains genomic integrity.
In the HEK293T context, disruption of APEX2 provides a powerful system to examine its contribution to DNA repair capacity and cellular responses to genotoxic agents. Because HEK293T cells express SV40 large T antigen, which inactivates p53 and Rb, the knockout model permits analysis of APEX2-dependent BER independently of these tumor suppressors. This is particularly relevant for studies of synthetic lethality, where APEX2 deficiency may sensitize cells to DNA-damaging chemotherapeutics or PARP inhibitors, and for exploring functional redundancy with APE1.
Typical research applications include DNA repair pathway analysis, cancer predisposition modeling, genotoxicity testing, and the validation of proximity labeling tools such as APEX2-based peroxidase reporters. Representative assays used with these cells encompass Western blotting for protein expression verification, RT-qPCR for transcript-level confirmation, immunofluorescence detection of ??H2AX foci as a marker of DNA double-strand breaks, the comet assay for assessing DNA damage, AP site cleavage activity measurements, and clonogenic survival assays to evaluate cellular sensitivity to genotoxic stress. For additional information or custom requests, please contact Ascent Research.
