The MRRF Knockout Raji Polyclonal Cells product comprises a population of Raji B lymphoblasts modified by CRISPR/Cas9-mediated disruption of the MRRF gene, generating a heterogeneous pool of cells with loss-of-function alleles. This polyclonal knockout format avoids clonal selection artifacts while enabling robust evaluation of MRRF-dependent mitochondrial processes. The genetic interruption targets the nuclear-encoded mitochondrial ribosome recycling factor, which is essential for disassembly of post-termination mitoribosomal complexes and subsequent recycling for new rounds of mitochondrial protein synthesis. These polyclonal knockout cells serve as a versatile model for dissecting mitochondrial translation regulation and its coupling to oxidative phosphorylation system (OXPHOS) biogenesis.
Raji cells are an Epstein-Barr virus (EBV)-positive B lymphoblastoid line derived from a Burkitt lymphoma patient. They exhibit a mature B-cell phenotype but lack surface immunoglobulin and constitutively express complement receptor type 2 (CR2/CD21). Their robust growth properties and suspension culture adaptability make them a workhorse for immunological and cancer research. Additionally, the EBV-driven transformation provides a nuclear antigen background that may intersect with mitochondrial-nuclear crosstalk, offering a unique context to study how mitochondrial translation defects influence lymphoblastoid cell physiology, antigen presentation capacity, and oncogenic signaling.
MRRF encodes the mitochondrial ribosome recycling factor (mtRRF), a translation factor that localizes to the mitochondrial matrix and, together with the mitochondrial release factor mtRF1a (MTRF1L) and the immature colon carcinoma transcript 1 (ICT1), mediates subunit dissociation of terminated mitoribosomes. This recycling step is critical for re-initiation of translation on mitochondrial mRNAs encoding core OXPHOS subunits such as MT-CO1, MT-CO2, MT-ATP6, and MT-ND1. The expression and activity of MRRF are transcriptionally controlled by master regulators of mitochondrial biogenesis, including PGC-1?? (PPARGC1A), NRF1 (nuclear respiratory factor 1), and GABPA. In the absence of functional MRRF, stalled post-termination complexes accumulate, mitochondrial protein synthesis declines, and the assembly of respiratory chain complexes is compromised, ultimately impairing oxidative phosphorylation capacity.
In the Raji B lymphoblast context, MRRF disruption provides a physiologically relevant model for combined oxidative phosphorylation deficiency 7 (COXPD7), a severe mitochondrial disorder with features of Leigh syndrome and encephalopathy. B lymphocytes rely on mitochondrial metabolism for activation, differentiation, and immune function, making this knockout particularly insightful for exploring how mitochondrial translation defects affect antigen presentation and lymphoproliferation. The polyclonal population mirrors heterogeneous gene editing outcomes, allowing researchers to assess how varying levels of MRRF loss impact mitochondrial protein synthesis and OXPHOS function in a cancer-derived lymphocyte background, thereby facilitating studies on metabolic reprogramming in lymphomas.
Researchers can leverage these cells for diverse experimental workflows. Mitochondrial translation efficiency can be directly monitored by 35S-methionine pulse-chase assays, while steady-state levels of MT-CO1 and MT-CO2 can be assessed via western blotting. Functional consequences on respiration are quantifiable through oxygen consumption rate (OCR) measurements using Seahorse analyzers and complex IV activity assays. RT-qPCR of mitochondrial transcripts distinguishes translational defects from transcriptional changes, and immunofluorescence reveals alterations in mitochondrial network morphology. Flow cytometric analysis of mitochondrial mass and membrane potential further characterizes metabolic states. These cells also support RNA-seq profiling to discern nuclear and mitochondrial transcriptome adaptations. For further details or customized applications, please contact Ascent Research.
