The DNAJB2 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HAP1 cell line. This product introduces a loss-of-function model for the DNAJB2 gene through CRISPR/Cas9-mediated gene disruption. The polyclonal format provides a heterogeneous mixture of edited alleles, offering a consistent knockout background without clonal selection.
HAP1 is a near-haploid human chronic myeloid leukemia (CML) cell line, originally derived from the KBM-7 line, which harbors the Philadelphia chromosome. The haploid nature of HAP1 cells simplifies genetic analysis, as only one allele requires targeting to achieve functional knockout. This feature makes HAP1 an ideal model system for CRISPR-based studies, enabling high-throughput screening and robust functional genomics experiments.
DNAJB2 encodes a co-chaperone (HSJ1) that facilitates Hsp70-mediated protein quality control. It recognizes misfolded polypeptides and, in concert with Hsp70 and the E3 ubiquitin ligase STUB1/CHIP, directs these substrates toward ubiquitination and degradation by the 26S proteasome. DNAJB2 activity is induced by proteotoxic stress via heat shock factor 1 (HSF1) and is critical for clearing aggregation-prone proteins such as huntingtin, tau, and SOD1 mutants. The chaperone network involves key factors including HSP70, DNAJB2, STUB1/CHIP, PSMD2 and BAG3, linking substrate recognition to the ubiquitin-proteasome system.
Knockout of DNAJB2 in HAP1 cells disrupts this degradation pathway, leading to accumulation of misfolded and aggregated proteins and consequent proteotoxic stress. This phenotype recapitulates aspects of neurodegenerative disorders, particularly distal hereditary motor neuropathy, Charcot-Marie-Tooth disease type 2T, and spinal muscular atrophy. The model thus provides a platform to investigate the cellular consequences of impaired protein homeostasis and to dissect the molecular mechanisms underlying motor neuron diseases.
These knockout cells are suitable for studying protein aggregation dynamics, chaperone-mediated degradation pathways, and disease-associated proteotoxicity. Researchers can employ western blotting and immunofluorescence to monitor client protein levels and aggregate formation, proteasome activity assays, cell viability tests under stress, ubiquitination assays, and co-immunoprecipitation to probe Hsp70/CHIP interactions. They are also valuable for drug screening efforts aimed at identifying proteostasis modulators. For further technical details, please contact Ascent Research.
