The IFIH1 Knockout HEK293T Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population targeting the human IFIH1 gene (encoding MDA5) in the HEK293T host background. This loss-of-function model is generated by CRISPR/Cas9-mediated gene disruption, resulting in a heterogeneous population of edited cells that collectively abolish functional MDA5 expression. As a polyclonal knockout resource, the product captures a diverse spectrum of editing events, making it suitable for studying the global impact of IFIH1 deficiency without clonal selection bias.
HEK293T cells are a widely used derivative of the human embryonic kidney HEK293 cell line, stably expressing the SV40 large T antigen. This modification enables episomal replication of plasmids containing the SV40 origin of replication, significantly enhancing transient protein expression and viral production. HEK293T cells are a cornerstone model for investigating signal transduction, gene regulation, and host-pathogen interactions, and serve as a robust platform for CRISPR-based gene editing due to their high transfection efficiency and well-characterized cellular behavior.
IFIH1 (MDA5) functions as a cytoplasmic pattern recognition receptor that specifically detects long double-stranded RNA (dsRNA), a molecular hallmark of viral replication. Upon dsRNA binding, MDA5 oligomerizes and interacts with the mitochondrial adaptor MAVS (also known as IPS-1/VISA/Cardif), thereby nucleating a signaling cascade. This interaction recruits and activates the noncanonical I??B kinases TBK1 and IKK??, which directly phosphorylate the transcription factors IRF3 and IRF7, as well as activate NF-??B. Phosphorylated IRF3 and IRF7 translocate to the nucleus to drive transcription of type I interferons (IFN-??/??) and interferon-stimulated genes (ISGs), mounting a potent antiviral state. The pathway is fine-tuned by regulatory factors such as TRIM25- and Riplet (RNF135)-mediated ubiquitination, and the helicase LGP2 (DHX58), which can modulate MDA5 sensitivity. In the knockout model, disruption of IFIH1 abrogates this dsRNA-sensing axis, preventing signal propagation to MAVS, TBK1, IRF3, and downstream effector molecules.
The HEK293T background provides a valuable cellular environment for interrogating the IFIH1 pathway. Given the host cell??s role in viral production and innate immune research, loss of MDA5 eliminates a key viral RNA sensor, allowing dissection of alternative antiviral pathways (e.g., RIG-I-dependent sensing) and off-target effects in gene editing contexts. This knockout model permits controlled investigation of type I interferonopathies, including Aicardi-Gouti??res syndrome and Singleton-Merten syndrome, which are characterized by dysregulated MDA5 signaling. Furthermore, the model circumvents the confounding variables introduced by viral immune evasion strategies, offering a clean genetic system to map signal transduction events from cytoplasmic RNA to interferon production.
These IFIH1 knockout polyclonal cells support diverse investigations into innate immunity. Typical assays include RT-qPCR and RNA-seq for gene expression analysis, western blotting for IRF3 phosphorylation, IFN-?? reporter assays, and co-immunoprecipitation of MDA5-MAVS complexes. Immunofluorescence visualizes MAVS aggregation, while viral infection assays differentiate MDA5- from RIG-I-dependent responses. The polyclonal format also enables pooled functional genomics screens. For ordering and technical details, please contact Ascent Research.
