The DNAJB9 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population with targeted disruption of the DNAJB9 gene in the human HT29 colorectal adenocarcinoma cell line. This loss-of-function model enables dissection of DNAJB9??s role as an ER luminal co-chaperone in maintaining ER proteostasis and modulating the unfolded protein response (UPR). The polyclonal format provides a heterogeneous pool of edited cells, avoiding clonal selection biases and enhancing experimental robustness for functional studies.
The HT29 cell line is a widely used human colorectal adenocarcinoma model with epithelial morphology, employed in research on intestinal epithelial biology and colorectal cancer. These cells exhibit characteristics of absorptive and mucus-secreting epithelium, making them valuable for studying tumor cell signaling, differentiation, and drug responses. Their genetic tractability enables CRISPR/Cas9-mediated gene editing, establishing a relevant background for probing colorectal cancer pathogenesis.
DNAJB9 encodes a DnaJ-domain-containing co-chaperone localized in the ER lumen, where it stimulates the ATPase activity of HSP70 chaperones such as BiP/GRP78 (HSPA5) and HSPA8. This functional interaction is critical for accelerating the chaperone cycle, facilitating protein folding and targeting misfolded proteins to the ER-associated degradation (ERAD) pathway. DNAJB9 expression is induced by ER stress agents like tunicamycin and thapsigargin via the UPR transcription factors ATF4 and XBP1s. DNAJB9 directly interacts with BiP/GRP78 and ERAD components including SEL1L and HRD1, linking it to the IRE1??-XBP1 and PERK-ATF4 signaling branches, and thus functioning as a key node in ER stress responses and proteostasis regulation.
In HT29 colorectal cancer cells, DNAJB9 knockout provides a platform to investigate how ER proteostasis controls malignant phenotypes. Colorectal tumors often encounter ER stress from oncogenic signaling and microenvironmental factors; therefore, loss of DNAJB9 may sensitize cells to ER stressors or impair adaptive UPR signaling. This model allows detailed examination of DNAJB9-dependent regulation of HSP70 chaperone complexes and ERAD efficiency, helping to identify proteostasis vulnerabilities that could be targeted in cancer therapy.
Applications include mechanistic studies of ER stress and UPR, chaperone-assisted folding, and ERAD in colorectal cancer. Representative assays are western blotting for BiP and CHOP, RT-qPCR for UPR genes, cell viability under drug-induced ER stress, immunofluorescence for ER morphology, co-immunoprecipitation of HSP70 complexes, and flow cytometric apoptosis analysis. Colony formation assays can evaluate tumorigenic capacity. For further details, please contact Ascent Research.
