The EIF2AK2 knockout HeLa polyclonal cells are a CRISPR/Cas9-edited heterogeneous population with targeted disruption of the EIF2AK2 gene, encoding the double-stranded RNA-activated protein kinase PKR. This polyclonal knockout model enables loss-of-function analysis of PKR in a flexible format suitable for diverse biochemical and viral challenge assays.
HeLa cells originate from human cervical adenocarcinoma and serve as a classic epithelial model for studying cancer biology, virology, and innate immunity. Their robust growth, susceptibility to many viruses, and intact interferon and stress signaling pathways make them an optimal host for interrogating PKR-dependent mechanisms.
PKR is activated by double-stranded RNA (dsRNA) or the cellular activator PACT, and its expression is induced by type I interferons (IFN-??/??) and TLR3 agonists. Upon activation, PKR phosphorylates eIF2??, inhibiting global translation while selectively upregulating translation of ATF4. ATF4 drives transcription of CHOP and pro-apoptotic factors like BAX. PKR also stimulates NF-??B, promoting inflammatory responses. Key interactors include TRBP, HSP90, P58IPK, and viral proteins such as HCV NS5A and adenovirus VAI RNA, which modulate PKR activity. Thus, PKR integrates signals from dsRNA sensing, interferon signaling, and the integrated stress response.
In the HeLa adenocarcinoma context, PKR knockout allows dissection of tumor-cell-intrinsic roles versus antiviral functions. Loss of PKR impacts stress granule formation, ER stress-induced apoptosis, and NF-??B survival signaling, all relevant to cancer progression and drug resistance. Additionally, HeLa cells?? HPV-18 positive status provides a unique backdrop to study viral oncoprotein interplay with PKR-mediated cell death. The knockout model clarifies PKR??s contribution to interferon-induced antiviral states and helps identify viral evasion tactics.
Applications include antiviral innate immunity, translational control, stress granule biology, and apoptosis. Representative assays: western blot for phospho-eIF2?? and CHOP, RT-qPCR for ATF4/CHOP, luciferase reporters for NF-??B/IFN-??, co-immunoprecipitation of PKR-PACT, immunofluorescence for stress granules, and viral replication assays. RNA-seq and ribosome profiling reveal PKR-dependent transcriptome changes. The cells are suited for drug screening targeting the integrated stress response. For additional information, contact Ascent Research.
