The DNAJB9 Knockout HAP1 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population in which the DNAJB9 gene has been disrupted in the HAP1 near-haploid human cell line. This product provides a versatile loss-of-function model for studying endoplasmic reticulum (ER) proteostasis and the unfolded protein response (UPR). The polyclonal nature of the knockout pool ensures a heterogeneous mixture of editing events across the cell population, offering a robust system for functional assays without the need for single-cell cloning. Researchers can utilize these cells to investigate DNAJB9-dependent pathways in a genetically tractable background.
The HAP1 cell line, derived from the KBM-7 chronic myeloid leukemia cell line, possesses a near-haploid karyotype, which greatly simplifies genetic manipulation and phenotypic analysis. Its haploid state means that disruption of a single allele is sufficient to generate a functional knockout, making HAP1 an ideal host for CRISPR-based gene editing and high-throughput genetic screens. Originally established as a model for leukemia research, HAP1 cells retain key signaling pathways relevant to cancer biology, while their adherent growth and rapid proliferation facilitate a wide range of cell-based assays.
DNAJB9 encodes an ER-resident co-chaperone that assists HSPA5/BiP in protein folding and facilitates ER-associated degradation (ERAD) of misfolded proteins. It interacts with IRE1 and EDEM1, positioning it at the nexus of chaperone activity and UPR signaling. Under ER stress, upstream regulators ATF6 and XBP1 induce UPR target genes, while DNAJB9 modulates IRE1 signaling. Knockout of DNAJB9 disrupts ER proteostasis, activating the PERK-eIF2??-ATF4 pathway and increasing CHOP expression, and alters XBP1 splicing, leading to UPR dysregulation.
In the HAP1 near-haploid background, this polyclonal knockout model offers a simplified genetic system for studying ER stress pathways. The haploid genome ensures clear genotype-phenotype relationships, and the polyclonal format allows robust bulk assays such as Western blotting for BiP and CHOP, or RT-qPCR for XBP1 splicing. The leukemia origin of HAP1 cells makes this knockout particularly relevant for exploring ER stress contributions to cancer cell survival and drug sensitivity, including response to proteasome inhibitors.
Applications include screening for UPR modulators, proteomic identification of DNAJB9 substrates, and functional studies of IRE1 signaling. Assays such as ER stress reporter assays, immunofluorescence, and viability tests under ER stress inducers are well supported. This model is valuable for investigating protein misfolding diseases and cancer. For further technical details or custom inquiries, please contact Ascent Research.
