The DNAJC1 knockout HAP1 polyclonal cells provide a heterogeneous pool of CRISPR/Cas9-edited HAP1 cells carrying targeted disruptions of the DNAJC1 gene. This polyclonal knockout population, generated by CRISPR/Cas9-mediated gene disruption, offers a robust tool for studying DNAJC1-dependent functions without the bias of clonal selection. The mixture of loss-of-function alleles recapitulates natural variation in knockout efficiency and is well-suited for phenotypic analyses where averaging across multiple edits mitigates clone-specific artifacts.
HAP1 is a near-haploid, fibroblast-like adherent cell line derived from the chronic myeloid leukemia KBM-7 line. Its near-haploid karyotype simplifies genetic manipulation because disruption of a single allele typically yields a complete loss-of-function phenotype. HAP1 cells retain signaling networks characteristic of myeloid leukemia, including active stress response and protein quality control pathways. Their robust growth and amenability to high-throughput screening make them a preferred system for functional genomics and CRISPR-based studies.
DNAJC1 encodes a co-chaperone that recruits HSPA8 to misfolded proteins, shuttling them towards refolding or ER-associated degradation (ERAD). The expression of DNAJC1 is controlled by heat shock factor 1 (HSF1) and ER stress transducers IRE1, ATF6, and PERK. DNAJC1 associates with HSPA8, DnaJ/Hsp40 family members, and ERAD components like DERL1 and VCP. Downstream, DNAJC1 facilitates the processing of HSPA8 clients and ERAD substrates; its loss leads to accumulation of misfolded polypeptides and activation of the unfolded protein response. Representative pathway nodes include HSPA5 (BiP), DERL1, and VCP, which collaborate with DNAJC1 to maintain proteostasis. Thus, DNAJC1 serves as a critical link between cytosolic chaperone machinery and ER quality control.
In HAP1 cells, DNAJC1 knockout perturbs the balance between chaperone-mediated refolding and degradation, creating a state of heightened proteotoxic stress and UPR engagement. Because HAP1 cells originate from CML, this model enables investigation of how leukemia-derived cells manage protein misfolding and whether they rely on specific proteostasis factors for survival. The near-haploid background ensures that phenotypes such as ER stress sensitivity and ubiquitinated protein accumulation are directly linked to DNAJC1 disruption, facilitating clear mechanistic interpretations.
This polyclonal knockout model is suited for functional genomics, protein homeostasis research, and ER stress studies. Typical assays include western blotting and RT-qPCR for UPR markers (e.g., BiP, CHOP), immunofluorescence for aggregation, and viability assays under ER stress-inducing drugs like tunicamycin. The polyclonal design supports haploid genetic screens to identify synthetic lethal interactions or modifiers of DNAJC1 function. Co-immunoprecipitation can still be applied to probe residual network interactions. For detailed product inquiries, please reach out to Ascent Research.
