The PCMT1 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population of Raji B lymphocytes featuring targeted disruption of the PCMT1 gene. This gene encodes protein-L-isoaspartate (D-aspartate) O-methyltransferase, an enzyme that repairs damaged proteins by methylating abnormal L-isoaspartyl and D-aspartyl residues. The polyclonal format provides a heterogeneous pool of knockout cells, minimizing clonal selection bias and enabling robust functional analyses of protein repair pathways in a lymphoid context.
The Raji cell line, originally derived from an Epstein-Barr virus (EBV)-positive Burkitt’s lymphoma patient, serves as a well-established model in immunology and cancer research. These B lymphocytes recapitulate key aspects of lymphomagenesis and viral oncogenesis. Raji cells proliferate in suspension, facilitating scalable culture and compatibility with a broad range of biochemical, pharmacological, and genetic perturbation assays, making them a versatile host for studying proteostatic mechanisms.
PCMT1 catalyzes the S-adenosylmethionine (SAM)-dependent methyl esterification of L-isoaspartyl and D-aspartyl residues in damaged proteins, converting them to native L-aspartyl forms and thereby restoring protein integrity. Its activity is induced by cellular stressors such as oxidative stress, heat shock, and DNA damage. Downstream, PCMT1 promotes protein stability, prevents aggregation, and supports cell survival. It interacts with damaged protein substrates and isoaspartyl dipeptidase, and its reaction generates S-adenosylhomocysteine, linking PCMT1 to the SAM cycle and methionine synthase activity. Thus, PCMT1 disruption cripples proteostatic repair, rendering cells sensitive to stress-induced proteotoxicity.
In Raji lymphoma cells, PCMT1 knockout impairs protein quality control, potentially exacerbating proteotoxic stress and altering apoptotic thresholds. This model is particularly relevant for exploring how malignant B cells manage elevated metabolic and replicative stress, and it may uncover vulnerabilities targetable by therapeutic agents. The EBV-positive background further permits investigation of virus?Chost interplay, as viral proteins may influence or depend on protein repair networks, offering insights into oncogenic stress adaptation.
Researchers can utilize these polyclonal knockout cells for diverse applications, including Western blotting, RT-qPCR, isoaspartyl protein detection via immuno- or mass spectrometry-based methods, cell viability assays (MTT or apoptosis), flow cytometry for apoptotic markers, protein aggregation assays, and SAM/S-adenosylhomocysteine quantification. These tools support studies of protein repair in aging, neurodegeneration, and cancer, as well as drug sensitivity screens targeting PCMT1. For additional technical details, please contact Ascent Research.
