The GTF2H5 Knockout NCI-H1975 Polyclonal Cells comprise a population of human lung adenocarcinoma epithelial cells subjected to CRISPR/Cas9-mediated disruption of the GTF2H5 gene. This polyclonal knockout cell product provides a heterogeneous loss-of-function model derived from the NCI-H1975 host line, enabling investigation of GTF2H5-dependent processes without clonal selection artifacts. The product format maintains a mixed genetic background, recapitulating biological variability in a genetically defined cancer cell context for advanced studies in transcription, DNA repair, and oncogenic signaling.
The parental NCI-H1975 cell line is a well-characterized model of non-small cell lung cancer, harboring activating EGFR L858R and T790M mutations along with a mutant TP53 allele. These genetic features drive constitutive oncogenic signaling and compromised tumor suppressor function, establishing a background of genomic instability. The epithelial origin and lung adenocarcinoma identity of these cells make them particularly relevant for investigating molecular mechanisms underlying tumor progression and therapeutic resistance in a clinically representative setting.
GTF2H5 encodes a small but essential subunit of the general transcription factor IIH (TFIIH) complex, a multifunctional assembly central to both RNA polymerase II transcription initiation and nucleotide excision repair (NER). Within TFIIH, GTF2H5 interacts directly with the helicase subunits ERCC3 (XPB) and ERCC2 (XPD), as well as with the regulatory submodule comprising CDK7, Cyclin H, and MAT1. The complex is dynamically activated by CDK7-mediated phosphorylation and is recruited to damaged DNA sites through signals from upstream DNA damage-responsive kinases ATM and ATR and the transcription factor TP53. Downstream, functional TFIIH enables assembly of the RNA polymerase II pre-initiation complex and coordinates with NER factors such as XPA and XPC to execute repair. Consequently, loss of GTF2H5 disrupts both global gene expression programs and the cell??s capacity to resolve UV- and chemically induced DNA lesions.
In the context of NCI-H1975 cells, ablation of GTF2H5 introduces a critical vulnerability in DNA repair and transcription regulation against a background of pre-existing oncogenic driver mutations. The inability to efficiently form a complete TFIIH complex is expected to impair NER, rendering the knockout cells hypersensitive to DNA-damaging agents such as cisplatin, a widely used chemotherapeutic. Moreover, crosstalk between defective transcription initiation and mutant TP53 may modulate cell cycle checkpoints and apoptosis, offering a platform to dissect how DNA repair deficiencies intersect with EGFR-driven signaling in lung adenocarcinoma. This model thus provides a tractable system to explore synthetic lethality and mechanisms of drug resistance.
Researchers can employ these polyclonal knockout cells for a variety of advanced applications, including assessing UV sensitivity via colony survival assays, quantifying DNA damage accumulation with comet and ??H2AX assays, and analyzing global transcriptional changes by RNA-seq or RNA polymerase II ChIP. Protein-level characterization of the disrupted TFIIH complex is possible through co-immunoprecipitation and western blotting of remaining subunits, while RT-qPCR can probe downstream transcriptional targets. The system is also suited for cell cycle profiling and exploring how GTF2H5 loss influences responses to platinum-based therapeutics. For detailed product information, qualification data, and customized solutions, please contact Ascent Research.
