The CHEK1 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited heterogeneous population of Raji B lymphocytes with targeted disruption of the CHEK1 gene. This polyclonal knockout model provides a loss-of-function system for investigating checkpoint kinase 1 (Chk1) in a human lymphoblastoid background, avoiding the clonal limitations of single-cell derivatives. The polyclonal format allows robust study of population-level responses to genotoxic stress and checkpoint modulation.
Raji cells are an Epstein-Barr virus (EBV)-positive Burkitt lymphoma-derived B cell line with rapid proliferation and active immunoglobulin secretion. Widely used in immunology and cancer research, this lymphoblastoid model is particularly suited to studying B-cell malignancies and viral interactions with host DNA repair machinery. The EBV positivity offers a unique context for exploring how viral proteins may influence DNA damage signaling.
CHEK1 encodes a serine/threonine kinase that functions as a master regulator of the DNA damage response. Upon genotoxic stress, Chk1 is activated by ATR/ATM kinases via the adaptor Claspin and Rad17, and subsequently phosphorylates downstream effectors including Cdc25A, Cdc25C, Wee1, p53, and Rad51. In coordination with 14-3-3 scaffold proteins, BRCA1, and Rad9, Chk1 enforces the G2/M and S phase checkpoints by modulating Cyclin B/Cdk1 activity. Disruption of CHEK1 in this polyclonal Raji population therefore impairs DNA damage-induced cell cycle arrest, increases genomic instability, and sensitizes cells to genotoxic agents.
In the Raji model, CHEK1 knockout recapitulates key features of checkpoint deficiency that are relevant to Burkitt lymphoma and other B-cell malignancies. The EBV-positive background further allows exploration of viral modulation of the DNA damage response and the role of Chk1 in maintaining genomic stability under conditions of replication stress. This system aids in dissecting Chk1-dependent survival pathways and identifying synthetic lethal interactions in lymphoma cells.
Researchers employ this model for DNA damage response studies using ??H2AX focus formation assays to quantify double-strand breaks. Cell cycle checkpoint analyses are performed by flow cytometry to monitor G2/M arrest following treatment with genotoxic agents. Drug sensitivity assays, including dose-response curves for chemotherapeutics and targeted inhibitors, reveal Chk1-dependent vulnerabilities. Additionally, proliferation and apoptosis measurements provide functional readouts, while synthetic lethality screens identify novel genetic interactions. For detailed protocol recommendations and product support, please contact Ascent Research.
