Description

The Bst2 Knockout CHO-K1 Cell Line is a CRISPR/Cas9-edited knockout cell line designed for loss-of-function analysis of BST2, the gene encoding the interferon-inducible antiviral restriction factor tetherin. This model provides stable disruption of the Bst2 locus in a CHO-K1 background, enabling precise investigation of BST2-dependent processes without native gene expression. The knockout cell line serves as a clean tool for studying viral particle tethering and innate immune signaling.

CHO-K1 cells, a subclone of the Chinese hamster ovary (Cricetulus griseus) line, possess an epithelial-like morphology and are widely used for recombinant protein production. Their robust growth, adaptability to suspension culture, and well-documented genome make them ideal hosts for biomanufacturing and biomedical research. The Bst2 knockout derivative maintains these traits while eliminating endogenous BST2 expression, offering a controlled system to dissect BST2-mediated host defense. Their non-human origin reduces confounding interactions with human-specific viral factors, facilitating analysis of conserved antiviral pathways.

BST2 encodes tetherin, a type II transmembrane protein strongly induced by type I interferons (IFN-??/??) via the IFNAR receptor complex. IFNAR activates JAK1 and TYK2 kinases, which phosphorylate STAT1 and STAT2, leading to formation of the ISGF3 complex with IRF9 that transactivates the BST2 promoter. IRF1, IRF3, and IRF7 also contribute to transcriptional regulation. The tetherin protein forms disulfide-linked dimers that insert into lipid rafts and physically cross-link budding enveloped virions to the plasma membrane, blocking release. BST2 additionally interacts with the actin cytoskeleton and modulates NF-??B activation. Viral antagonists, including HIV-1 Vpu and Ebola GP2, directly counter BST2, highlighting its essential role in innate antiviral immunity.

In CHO-K1 cells, Bst2 knockout eliminates the cell-autonomous block to viral egress imposed by tetherin. This is valuable for studies of retroviruses, filoviruses, and other enveloped viruses where BST2-mediated tethering complicates viral release kinetics. Since CHO-K1 cells lack certain human-specific viral receptors, they can be engineered to express requisite entry factors, while the Bst2 knockout ensures that any restriction observed is independent of endogenous tetherin. This allows clean dissection of host?Cpathogen interactions and screening of antiviral compounds targeting BST2 or viral countermeasures.

Applications include viral release inhibition studies, host?Cpathogen interaction screening, antiviral drug discovery, and interferon response profiling. Researchers can use western blotting, RT-qPCR, flow cytometry, immunofluorescence, p24 ELISA, or viral titer assays to monitor BST2 expression and function. The cell line is suitable for co-culture experiments and reconstitution with wild-type or mutant BST2 constructs to map functional domains. For further information, please contact Ascent Research.