The MBD4 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population derived from the Raji B lymphocyte line, featuring targeted disruption of the MBD4 gene encoding a thymine DNA glycosylase essential for base excision repair. This polyclonal pool provides a heterogeneous loss-of-function model without clonal selection bias, suitable for studying MBD4-dependent genomic stability and mutation prevention.
Raji cells originate from an EBV-positive African Burkitt lymphoma bearing the t(8;14) MYC-IgH translocation. As lymphoblastoid B cells, they are capable of antibody production and antigen presentation, making them a standard model for B-cell biology and lymphoma research. Their suspension growth and rapid proliferation facilitate high-throughput assays. Introducing MBD4 knockout into this background allows investigation of DNA repair dynamics in lymphomagenesis.
MBD4 is a DNA glycosylase that excises thymine from G:T mismatches generated by deamination of 5-methylcytosine at CpG sites. It initiates base excision repair, engaging downstream factors APEX1, POLB, LIG3, and XRCC1 to restore G:C pairs. MBD4 activity is activated by DNA damage signaling (ATM/ATR) and transcriptionally regulated by E2F1. The protein interacts with MLH1, MBD1, HDAC1, and SIN3A, and functions within pathways involving DNMT1 and TDG. By correcting pre-mutagenic lesions, MBD4 suppresses C>T transition mutations, preserves CpG stability, and contributes to DNA demethylation, thereby maintaining genomic integrity.
In Raji cells, MBD4 deficiency is expected to impair base excision repair at CpG islands, increasing mutational burden and potentially cooperating with MYC-driven oncogenesis and EBV-mediated proliferation. This model enables dissection of DNA repair defects in lymphomagenesis and hypermutation during antibody class switching, where AID-induced deamination can create substrates for MBD4. Consequently, these cells are valuable for studying hyper-IgM syndrome type 2 and exploring how defective repair contributes to immune dysfunction and transformation.
Applications include glycosylase activity assays, comet assays, bisulfite sequencing for CpG mutation analysis, and next-generation sequencing for mutational signatures. The cells are also suitable for drug sensitivity testing with DNA-damaging agents and flow cytometric measurement of ??-H2AX foci. This model supports research in cancer epigenetics, DNA repair, and therapeutic resistance. For further information, contact Ascent Research.
