The MSH6 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the MSH6 gene in the Raji B lymphoblastoid background. This polyclonal format provides a heterogeneous mixture of cells with diverse CRISPR-mediated target-gene disruptions, allowing researchers to interrogate loss-of-function phenotypes across a genetically varied population. The knockout model serves as a powerful tool to dissect DNA mismatch repair (MMR) biology and to recapitulate repair-deficient states relevant to Lynch syndrome and microsatellite instability-high (MSI-H) malignancies.
Raji cells are a well-characterized human Burkitt lymphoma line that maintains an Epstein-Barr virus (EBV)-positive, B lymphoblastoid phenotype. Widely utilized as a suspension-culture model for B-cell lymphoma and EBV biology, Raji cells exhibit rapid proliferation and stable karyotype, making them amenable to high-throughput genetic perturbation and functional studies. Their lymphoid origin and immortalized state provide a physiologically relevant context for investigating MMR deficiency in hematopoietic malignancies and for exploring how compromised genomic maintenance intersects with oncogenic viral programs.
At the molecular level, MSH6 encodes a core MMR protein that heterodimerizes with MSH2 to form the MutS?? complex, which recognizes base-base mismatches and small insertion/deletion loops. MutS?? then recruits the MutL?? heterodimer, composed of MLH1 and PMS2, initiating downstream repair events that involve EXO1-mediated excision, PCNA-directed resynthesis, and ligation by LIG1. MSH6 transcription is regulated by E2F family members during cell cycle progression and is induced by p53 in response to genotoxic stress. Interacting partners such as RFC, RPA, and HMGB1 further coordinate lesion processing. CRISPR/Cas9-mediated disruption of MSH6 ablates MutS?? function, decoupling mismatch recognition from downstream repair, thereby fostering a mutator phenotype characterized by elevated microsatellite instability and hypermutation.
In the Raji cellular context, MSH6 knockout recapitulates key features of Lynch syndrome-associated MMR deficiency, providing a tractable model to study the consequences of defective repair in B-lymphoid cells. The engineered cells enable systematic investigation of how MSH6 loss cooperates with EBV-driven transformation to accelerate genomic instability. This system is particularly valuable for identifying synthetic lethal interactions with MMR deficiency, for profiling sensitivity to DNA-damaging chemotherapeutics such as platinum agents and temozolomide, and for evaluating PARP inhibitor efficacy in MSI-H backgrounds. The polyclonal nature also supports pooled screening approaches to map genetic dependencies and to assess the functional heterogeneity of MMR-deficient populations.
Researchers can employ this knockout product in a wide range of assays, including Western blotting and RT-qPCR to confirm MSH6 ablation, sequencing of mononucleotide or dinucleotide repeat loci to validate the MSI phenotype, and HPRT or lacZ mutation frequency assays to quantitate spontaneous mutagenesis. Drug sensitivity profiling with cisplatin, 6-thioguanine, and PARP inhibitors, comet assay for DNA damage accumulation, and immunofluorescence to visualize MMR foci further expand experimental utility. For additional details or to discuss customization options, please contact Ascent Research.
