The FBXL18 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human Raji B lymphocyte line. This product provides a loss-of-function model with disruption of the FBXL18 gene, enabling functional dissection of FBXL18-mediated processes in a lymphoid context. The polyclonal nature preserves the heterogeneous editing outcomes typical of a pool of edited cells, offering a versatile system for studying gene-disrupted phenotypes without clonal selection. Researchers can employ this model to dissect the ubiquitin-proteasome and JNK signaling pathways within an EBV-positive Burkitt lymphoma background.
The Raji cell line originates from a human Burkitt lymphoma and presents a B lymphocyte phenotype characterized by expression of surface immunoglobulin and Epstein?CBarr virus (EBV) latent genes. These cells are widely used in immunology and oncology to study B-cell biology, humoral immunity, and lymphomagenesis. As an EBV-positive lymphoblastoid cell line, Raji provides a unique platform for investigating how viral latency intersects with host signaling networks. Its robust growth in suspension culture and well-characterized molecular landscape make it a suitable host for CRISPR/Cas9-mediated gene disruption, enabling mechanistic studies of B-cell receptor signaling, apoptosis, and oncogenic transformation.
FBXL18 encodes an F-box protein that functions as the substrate recognition subunit of the SKP1?CCUL1?CRBX1 (SCF) E3 ubiquitin ligase complex. Within this complex, FBXL18 specifically engages MKK7 (MAP2K7), the upstream kinase of JNK, marking it for K48-linked polyubiquitination and subsequent proteasomal degradation. This ubiquitin-dependent turnover of MKK7 serves to attenuate JNK-mediated signaling cascades, reducing the phosphorylation of c-Jun and other JNK substrates. FBXL18 activity is responsive to cellular stress and inflammatory cytokines, which modulate SCF E3 ligase assembly or substrate availability, thereby fine-tuning the strength and duration of JNK pathway activation. Downstream, the JNK pathway regulates transcription factors such as c-Jun, impacting gene expression programs that control cell proliferation, survival, and stress responses. Interacting partners SKP1, CUL1, and RBX1 are essential for ligase activity, while MKK7 and JNK represent core components of the signaling axis directly affected by FBXL18 expression levels.
In Raji B lymphocytes, FBXL18-mediated degradation of MKK7 plays a critical role in maintaining balanced JNK signaling, which influences apoptosis sensitivity and cell fate decisions. Dysregulation of the ubiquitin-proteasome system is frequently observed in B-cell lymphomas, and perturbations in FBXL18 expression may contribute to aberrant JNK pathway activity, altering the threshold for stress-induced cell death. By knocking out FBXL18 in this EBV-positive lymphoblastoid background, researchers can interrogate how the SCF E3 ligase complex integrates oncogenic and stress signals to control B-cell homeostasis. This model also facilitates exploration of the interplay between FBXL18-dependent ubiquitination and viral latency programs, given the EBV-positive status of Raji cells. Consequently, the FBXL18 knockout polyclonal population serves as a powerful tool for functional genomics in B-cell lymphoma research, allowing dissection of the molecular circuitry that links ubiquitin-dependent proteolysis to JNK-driven transcriptional responses.
The FBXL18 Knockout Raji Polyclonal Cells are ideally suited for a wide range of experimental applications in ubiquitin biology and signal transduction. Investigators can perform Western blotting and RT?qPCR to confirm FBXL18 ablation and assess compensatory responses in related F-box proteins. Co?immunoprecipitation assays enable verification of the disrupted interaction between FBXL18 and core SCF components (SKP1, CUL1) as well as its substrate MKK7. Phospho?JNK analysis by immunoblotting or flow cytometry allows quantification of JNK pathway activation following knockout, while cell viability and apoptosis assays measure the functional impact on Raji cell survival. These readouts support drug target validation, high?throughput screening, and systematic analysis of the ubiquitin?Cproteasome pathway in a lymphoma?derived background. For additional information, experimental protocols, or technical assistance, please contact Ascent Research.
