The IFIH1 Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited population of A-549 cells with targeted disruption of the IFIH1 gene, generating a heterogeneous polyclonal knockout model for the cytoplasmic dsRNA sensor MDA5. This product offers a versatile platform for loss-of-function studies in innate antiviral immunity, eliminating the need for single-cell cloning while preserving genetic diversity.
The parental A-549 cell line is an adherent epithelial line derived from a lung adenocarcinoma of a 58-year-old male. It serves as a well-characterized in vitro model of human alveolar type II epithelium and is widely employed in cancer biology, drug discovery, and viral infection research, particularly for respiratory pathogens that target the pulmonary epithelium.
IFIH1 (MDA5) recognizes long double-stranded RNA from viral genomes or synthetic analogs like poly I:C. Upon ligand binding, IFIH1 interacts with the adaptor protein MAVS, triggering activation of the kinases TBK1 and IKK??, which phosphorylate IRF3 and IRF7, leading to type I interferon (IFN-??/??) production. Parallel NF-??B activation induces pro-inflammatory cytokines. IFIH1 function is modulated by interactions with RIG-I, LGP2, and TRIM25, and is targeted by viral antagonists such as paramyxovirus V proteins.
In the A-549 epithelial context, IFIH1 disruption abrogates the major cytoplasmic RNA-sensing pathway, providing a clean genetic background to analyze host responses to respiratory viruses including SARS-CoV-2, influenza A virus, and picornaviruses. The model is also instrumental in studying IFIH1 gain-of-function mutations linked to Aicardi-Gouti??res syndrome and Singleton-Merten syndrome, and in evaluating compensatory signaling by RIG-I.
These polyclonal knockout cells are suitable for a range of experimental applications, including viral infection assays (plaque or immunofluorescence readouts), poly I:C stimulation to assess alternative pathways, and quantitative measurement of IFN-?? production by ELISA. Knockout validation can be performed by RT-qPCR for IFIH1 mRNA and western blotting for MDA5 and key signaling mediators such as phosphorylated TBK1, IRF3, and STAT1. Global transcriptional responses can be examined by RNA-seq, and interferon-stimulated gene expression (e.g., CXCL10) can serve as a functional readout. For further technical information or custom applications, please contact Ascent Research.
