EIF4B Knockout Marc-145 Cell Line

The EIF4B Knockout Marc-145 Cell Line is a CRISPR/Cas9-edited knockout cell line engineered from the Marc-145 parental line, featuring targeted disruption of the endogenous EIF4B gene to eliminate eukaryotic translation initiation factor 4B expression. This stable loss-of-function model allows for precise elucidation of EIF4B??s role in cap-dependent translation, especially for mRNAs with structured 5?? UTRs, including oncogenic transcripts such as c-MYC, CCND1, BCL2, and VEGF.

Marc-145 cells are an adherent kidney epithelial line originating from fetal African green monkey (Chlorocebus aethiops) and subcloned from MA-104 cells. They are extensively utilized as a highly permissive host for propagating porcine reproductive and respiratory syndrome virus (PRRSV) and for studying viral entry, replication, and host factor requirements. The knockout of EIF4B in this background offers a powerful tool to examine the translational demands of viral infection and host dependency factors.

EIF4B serves as a key cofactor that enhances the ATP-dependent helicase activity of eIF4A, facilitating unwinding of mRNA 5?? UTR secondary structures during translation initiation. It is recruited to the preinitiation complex through direct interactions with eIF4G, eIF3, and poly(A)-binding protein PABPC1, and its activity is regulated by phosphorylation at multiple residues. Upstream signaling through mTORC1/S6K1, PI3K/AKT, and the RAS/ERK/RSK cascade converges on EIF4B upon mitogenic or nutrient stimulation, thereby promoting selective translation of proliferation-related and survival mRNAs. Consequently, EIF4B acts as a critical integrator of growth signals to the protein synthesis machinery.

In the Marc-145 kidney epithelial environment, disruption of EIF4B is expected to globally attenuate cap-dependent translation initiation, with pronounced effects on viral replication that depends on intact host translation apparatus. Since PRRSV and other viruses rely on host eIF4F components for their own protein synthesis, EIF4B knockout likely hampers viral propagation, making this cell line a valuable resource for investigating host-virus interplay and for testing host-directed antiviral strategies that target translation factors.

This knockout line is suitable for a range of experimental approaches, including western blotting for target validation and downstream effector analysis, polysome profiling to assess translation efficiency, RT-qPCR for transcriptional changes of proliferation-related genes, viral titer determination, and functional assays such as MTT, BrdU, cap-binding assays, and reporter-based translation readouts. These methods enable robust characterization of EIF4B-dependent translation under normal and disease conditions. For further information or to request a quote, please contact Ascent Research.