The EIF1B Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the EIF1B gene in the near-haploid HAP1 human cell line. This heterogeneous population harbors targeted disruptions of the EIF1B locus, enabling loss-of-function studies without requiring clonal isolation. The polyclonal format captures a range of indel mutations across the pool, providing a robust model for investigating the functional consequences of EIF1B deficiency in a near-haploid genetic background.
The host cell line, HAP1, is a near-haploid human cell line originally derived from a male patient with chronic myeloid leukemia (CML). Its haploid karyotype simplifies genetic analysis by reducing gene redundancy, making it an ideal platform for knockout studies, high-throughput genetic screens, and CRISPR-based functional genomics. HAP1 cells retain key signaling pathways and have been extensively used to dissect mechanisms of disease and drug action.
EIF1B encodes eukaryotic translation initiation factor 1B, a critical component of the translation initiation complex that enhances the fidelity of start codon selection during ribosomal scanning. It interacts directly with the 40S ribosomal subunit and cooperates with other initiation factors such as eIF1A, eIF2, eIF3, and eIF5. EIF1B activity is regulated upstream by the mTORC1 pathway and by eIF2?? kinases (e.g., PKR, PERK) in response to growth factor signals (insulin/IGF-1) and cellular stress. Loss of EIF1B perturbs scanning fidelity, leading to altered translation of mRNAs with regulatory upstream open reading frames (uORFs), notably ATF4 and CHOP, key effectors of the integrated stress response.
In the HAP1 context, the near-haploid genome ensures that targeted disruption of the single EIF1B allele results in a direct loss-of-function phenotype, without confounding effects from a second allele. This model is therefore particularly valuable for dissecting EIF1B??s role in translation initiation fidelity, stress-induced translational reprogramming, and mTOR-mediated growth control. The polyclonal pool also facilitates pooled screening applications where phenotypic heterogeneity can be assessed.
Typical applications include mechanistic studies of translation initiation using ribosome footprinting and polysome profiling, high-throughput genetic screens to identify modulators of the integrated stress response, and dual-luciferase reporter assays to evaluate uORF activity. The cells are also suited for drug target validation in translation-dependent diseases such as cancer and neurodegeneration, and for synthetic lethality screens with mTOR inhibitors or other translation-targeting agents. Additional techniques such as puromycin incorporation assays, western blotting for translation factors, and RNA-seq can be employed to characterize the functional impact of EIF1B loss. For further details or assistance with experimental design, please contact Ascent Research.
