The MLEC Knockout Raji Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population derived from the Raji B lymphocyte cell line, featuring targeted disruption of the MLEC gene. This product provides a pooled population of knockout cells suitable for functional studies of malectin, an endoplasmic reticulum (ER)-resident lectin involved in glycoprotein quality control and ER stress signaling. The polyclonal format offers a heterogeneous mixture of gene-edited cells, enabling a robust loss-of-function model without the selection bottleneck of a single clone. The knockout was generated using CRISPR/Cas9-mediated gene disruption, eliminating the need for specific editing-pattern characterization.
The parental Raji cell line originates from a Burkitt lymphoma patient and is an Epstein-Barr virus (EBV)-positive B lymphoblast. These suspension cells retain key features of B lymphocyte biology, including antibody production, antigen presentation, and immune surveillance capabilities. As a model for B cell malignancies, Raji cells are widely used to study lymphomagenesis, immune cell signaling, and the effects of oncogenic transformation. Their B cell identity makes them particularly relevant for investigating how ER protein quality control pathways intersect with secretory function, since antibody-producing cells place a heavy demand on the ER.
MLEC encodes malectin, which specifically recognizes Glc2Man9GlcNAc2 N-glycans on misfolded glycoproteins within the ER lumen. Malectin collaborates with OS9 and EDEM1 to triage misfolded substrates, targeting them to the SEL1L-HRD1 (SYVN1) E3 ubiquitin ligase complex for retrotranslocation and proteasomal degradation via ER-associated degradation (ERAD). It also interacts with calnexin and calreticulin within the glycoprotein folding cycle. Upon MLEC disruption, accumulation of misfolded glycoproteins triggers the unfolded protein response (UPR), activating stress sensors IRE1?? (ERN1), PERK (EIF2AK3), and ATF6. Downstream transcription factors XBP1, ATF4, and ATF6 upregulate ER chaperones like BiP (HSPA5) and components of ERAD, attempting to restore homeostasis. Thus, MLEC acts as a gatekeeper at the nexus of glycoprotein folding quality control and ER stress signaling.
In the Raji B lymphocyte background, MLEC knockout models the consequences of defective ER protein quality control in a cell type with high secretory demand. As B cell lymphoblasts, Raji cells rely heavily on proper antibody folding and secretion, making them sensitive to ER stress. Loss of malectin may impair the degradation of misfolded immunoglobulins and other glycoproteins, leading to chronic UPR activation. This model can be used to dissect how B cell lymphomas adapt to ER stress and to identify vulnerabilities that arise from compromised ERAD. Moreover, the EBV-positive status of Raji cells adds a layer of complexity, as viral proteins may interact with host ER quality control machinery, providing insights into virus-host interactions in oncogenesis.
Researchers can employ this MLEC knockout model to investigate ER protein quality control, glycoprotein folding and ERAD, and UPR signaling dynamics. Representative experimental approaches include Western blotting to monitor UPR markers such as BiP and CHOP, RT-qPCR for spliced XBP1 and ATF4 transcripts, and flow cytometry using ER stress-responsive fluorescent reporters. Co-immunoprecipitation of malectin with ERAD components (e.g., OS9, HRD1) and lectin pull-down assays can confirm loss of function. Immunofluorescence for ER morphology and viability assays under ER stress inducers like tunicamycin or thapsigargin are also highly informative. This knockout cell population serves as a valuable tool for dissecting ER proteostasis and its implications in cancer, metabolic disorders, and neurodegenerative diseases. For technical inquiries or custom gene-editing requests, please contact Ascent Research.
