OTULIN Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population with disrupted OTULIN, offering a loss-of-function model for investigating linear ubiquitination and NF-??B signaling. This heterogeneous pool of Raji cells carries targeted OTULIN gene disruptions, enabling study of OTULIN-dependent regulatory mechanisms without clonal selection artifacts. The polyclonal format preserves genetic diversity while ensuring consistent knockout effects across the population, making it suitable for biochemical, functional, and pharmacological assays.
The Raji host cell line is an Epstein-Barr virus (EBV)-positive Burkitt lymphoma-derived B lymphoblastoid line, widely used to model B cell malignancies and immune responses. These immortalized cells display mature B lymphocyte characteristics and constitutive survival pathway activation, providing a relevant system for examining B cell receptor signaling and inflammatory cytokine production. The OTULIN knockout in this background creates a human B-cell context for dissecting the interplay between linear ubiquitination and immune signaling.
OTULIN specifically cleaves Met1-linked (linear) ubiquitin chains, functioning as a key negative regulator of NF-??B signaling and inflammation. It acts upstream of the IKK complex by removing linear ubiquitin from substrates such as NEMO and RIPK1, thereby counteracting LUBAC (HOIP/HOIL-1/SHARPIN)-mediated linear ubiquitination. Activation by TNF-??, IL-1??, or LPS through TNFR1 triggers LUBAC to attach linear chains, which OTULIN then trims. OTULIN interacts directly with HOIP and deubiquitinates signaling components, attenuating NF-??B transcriptional activity and reducing production of pro-inflammatory cytokines like IL-6 and TNF-??.
In Raji B cells, OTULIN disruption leads to accumulation of linear ubiquitin chains on LUBAC substrates, causing NF-??B hyperactivation and exaggerated inflammatory gene expression. This mirrors features of OTULIN-related autoinflammatory syndrome (otulipenia), a disorder resulting from OTULIN loss-of-function. The knockout cells offer a human B-lymphocyte platform to study molecular mechanisms of immune dysregulation and to screen for compounds that modulate linear ubiquitination and NF-??B signaling. Their immortalized nature supports high-throughput and long-term investigations for drug discovery targeting inflammatory conditions.
Applications encompass Western blotting to detect linear ubiquitin chain levels and NF-??B pathway phosphorylation, RT-qPCR to measure NF-??B target gene upregulation, ELISA to quantify IL-6 and TNF-?? secretion, and co-immunoprecipitation to probe OTULIN-LUBAC interactions. Flow cytometry can assess B cell markers and apoptosis, while NF-??B luciferase reporter assays provide functional readouts. These OTULIN knockout polyclonal cells serve as a versatile tool for investigating linear ubiquitination-dependent signaling and developing therapies for autoinflammatory diseases and B-cell malignancies. For more information, contact Ascent Research.
