The DNAJB9 Knockout HeLa Polyclonal Cells consist of a CRISPR/Cas9-edited polyclonal HeLa population carrying a targeted disruption of the DNAJB9 gene. This knockout model enables investigation of the ER-resident HSP40 co-chaperone in unfolded protein response (UPR) and proteostasis. The polyclonal format provides a heterogeneous knockout pool suitable for population-level assays.
HeLa cells are an immortalized human epithelial cell line derived from cervical adenocarcinoma, with constitutive expression of HPV18 oncoproteins. These cells are a standard model for cancer biology and cell signaling, exhibiting robust adherent growth and well-defined responses to pharmacological perturbations. They have been extensively employed in UPR studies, providing a reliable platform for evaluating ER stress responses. The epithelial origin and HPV-driven background render them particularly suitable for investigating ER stress pathways linked to oncogenesis.
DNAJB9 is an ER-localized HSP40 co-chaperone that partners with HSPA5/BiP to facilitate protein folding and suppress aggregation. It is transcriptionally upregulated by ER stress through IRE1???CXBP1s and ATF6 signaling. DNAJB9 directly interacts with IRE1??, attenuating its activity to modulate UPR outputs and promote adaptive survival signals. The protein also engages with calnexin/calreticulin cycle components, protein disulfide isomerases, and ERAD efficiency. Downstream, it influences expression of CHOP and GADD34 and ERAD via HRD1-SEL1L and VCP/p97.
In HeLa cells, DNAJB9 knockout sensitizes the cells to ER stress-induced apoptosis, demonstrated by enhanced CHOP induction and caspase activation upon tunicamycin treatment. The HPV18 E6-mediated degradation of p53 already lowers the apoptotic threshold, so loss of DNAJB9 further compromises stress resilience and disrupts ERAD capacity. This model is valuable for dissecting how UPR signaling integrates with oncogenic pathways to determine cell fate and for drug screening.
Applications include Western blotting for BiP and CHOP, RT-qPCR for XBP1 splicing, and cell viability assays for screening ER stress modulators. Flow cytometry with Annexin V staining quantifies apoptosis, while immunofluorescence visualizes ER morphology. Co-immunoprecipitation can probe interactions with HSPA5 and IRE1??. Transcriptomic analysis via RNA-seq can uncover global regulatory changes. Furthermore, this model can be integrated into high-content screening for ER stress-modifying compounds. For further details, contact Ascent Research.
