The ISG15 Knockout SK-HEP-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population derived from the human SK-HEP-1 hepatic adenocarcinoma cell line. This product introduces targeted disruptions in the ISG15 gene, generating a heterogeneous pool of cells for loss-of-function studies. The polyclonal format preserves genetic diversity and avoids single-cell cloning artifacts, making it suitable for pooled functional assays. These cells provide a relevant model to investigate ISG15-dependent processes in a liver cancer context.
SK-HEP-1 cells were originally isolated from a patient with adenocarcinoma of the liver and are widely used as a hepatocellular carcinoma model. They exhibit epithelial morphology and are amenable to various experimental manipulations, including viral infection and interferon stimulation. The hepatic origin is particularly relevant for studying innate immune responses, as the liver is a major site of interferon production and action. The SK-HEP-1 background thus offers a physiologically meaningful platform to dissect ISG15 function in hepatic oncogenesis and antiviral immunity.
ISG15 encodes a ubiquitin-like protein strongly induced by type I interferons (IFN-??/??) and IFN-?? through the JAK-STAT pathway. Upon interferon binding to IFNAR1/IFNAR2, JAK1 and TYK2 phosphorylate STAT1 and STAT2, which complex with IRF9 to drive ISG15 transcription. IRF3 and IRF7 also contribute to induction. ISG15 conjugation (ISGylation) requires the E1 enzyme UBA7, the E2 enzyme UBE2L6, and the E3 ligase HERC5, while USP18 removes ISG15. ISGylation modifies key substrates including IRF3, PKR, RIG-I, and IFIT proteins, thereby modulating antiviral signaling, protein stability, and additional pathways such as NF-??B. Extracellular free ISG15 can also trigger cytokine secretion.
Disruption of ISG15 in SK-HEP-1 cells creates a powerful tool to examine ISGylation-dependent effects on interferon responses and viral susceptibility. Given the liver??s central role in antiviral defense, this model is valuable for studying hepatitis viruses and other hepatotropic pathogens. Moreover, because ISG15 can exhibit either tumor-suppressive or oncogenic functions, the knockout cells enable investigation of its role in hepatocellular carcinoma progression, including effects on migration and invasion.
Researchers can employ this polyclonal knockout population in diverse assays, including western blotting for ISG15 and ISGylation, RT-qPCR for ISG15 and interferon-stimulated genes, interferon stimulation assays, co-immunoprecipitation of ISGylation targets, viral replication experiments, flow cytometry for phosphorylated STAT1, and migration/invasion assays. It is also suited for drug screening targeting ISG15-related pathways. For additional details, please contact Ascent Research.
