The EIF2AK1 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal cell population derived from the HT29 human colorectal adenocarcinoma cell line, featuring targeted disruption of the EIF2AK1 gene. This polyclonal knockout model provides a heterogeneous loss-of-function system for investigating HRI kinase activity and the integrated stress response without the constraints of monoclonal selection. The cells are supplied as a viable, ready-to-culture population suitable for a wide array of biochemical and functional assays.
HT29 cells are a well-characterized epithelial cell line isolated from a primary colorectal adenocarcinoma, widely employed as a model for intestinal cancer biology, drug metabolism, and epithelial differentiation. Their robust growth characteristics, defined genetic background, and relevance to human colorectal cancer make them an ideal host for gene disruption studies. The utilization of HT29 as the parental line ensures that the resulting knockout model retains key oncogenic and epithelial features essential for investigating cancer-related stress signaling pathways.
EIF2AK1 encodes the heme-regulated inhibitor (HRI) kinase, a master sensor of heme deficiency, oxidative stress, and proteotoxicity. Under basal conditions, HRI is inhibited by heme and Hsp90; however, upon heme depletion, arsenite exposure, heat shock, or proteasome inhibition, HRI undergoes activation and directly phosphorylates the ?? subunit of eIF2 on Ser51. This phosphorylation event reduces global protein translation while selectively upregulating the translation of ATF4. ATF4 then transcriptionally induces stress-responsive genes, including CHOP (DDIT3), GADD34 (PPP1R15A), and ATF3, forming a negative feedback loop that restores cellular homeostasis. Additionally, HRI-mediated signaling converges on NRF2 to modulate antioxidant responses, integrating translational control with redox balance.
In HT29 cells, the EIF2AK1 knockout disrupts HRI-dependent eIF2?? phosphorylation and downstream ISR activation, impairing the ability to cope with exogenous stressors such as oxidative agents or proteasome inhibitors. Given that colorectal cancer cells often encounter fluctuating microenvironments with varying oxygen and nutrient levels, this knockout model provides a powerful tool to dissect the role of HRI in tumor cell adaptation and survival. The loss of HRI may sensitize HT29 cells to certain chemotherapeutic agents, making this a pertinent system for studying drug resistance mechanisms in colorectal adenocarcinoma.
This polyclonal knockout product supports a broad spectrum of research applications, including detailed dissection of the integrated stress response, investigation of erythropoiesis and anemia disorders such as ??-thalassemia, and mechanistic studies of oxidative stress biology. Representative experimental approaches include western blotting for phospho-eIF2?? and ATF4, RT-qPCR for ATF4, CHOP, and GADD34 transcript levels, flow cytometry for apoptosis assessment under stress conditions, ATF4 luciferase reporter assays, and drug sensitivity profiling with proteasome inhibitors. Furthermore, the cells are suitable for ROS measurement and high-content screening of small-molecule HRI modulators. For additional technical support and ordering information, please contact Ascent Research.
