The GTF2H5 Knockout HT29 Polyclonal Cells are a human colorectal adenocarcinoma-derived research tool featuring CRISPR/Cas9-mediated disruption of the GTF2H5 gene to generate a heterogeneous polyclonal knockout population. This product provides a physiologically relevant loss-of-function model for investigating the role of the GTF2H5-encoded p8 subunit of the TFIIH complex in transcription initiation and nucleotide excision repair (NER).
The parental HT29 cell line is an adherent, human colorectal adenocarcinoma cell line capable of forming polarized monolayers with functional tight junctions. Widely used to study intestinal epithelial barrier function, absorption, and transepithelial transport, HT29 cells offer a robust host background for dissecting the contributions of GTF2H5 to genome maintenance and transcriptional regulation in a colorectal cancer context.
GTF2H5 serves as a structural component of the core TFIIH complex, stabilizing the assembly and facilitating both RNA polymerase II transcription initiation and NER. TFIIH function is activated by UV-induced DNA damage and regulated by the CDK7-cyclin H-MAT1 kinase module. Upon activation, TFIIH phosphorylates the C-terminal domain of RNA polymerase II and engages XPB and XPD helicases. GTF2H5 interacts directly with multiple TFIIH subunits, including XPB, XPD, p62, p52, p44, p34, p8, MAT1, cyclin H, and CDK7, linking DNA damage sensing to repair and transcription.
Disruption of GTF2H5 in HT29 cells compromises TFIIH integrity, leading to impaired NER and transcription defects. This model is particularly relevant for colorectal cancer research, where genomic instability and defective DNA repair are hallmarks. It enables exploration of how GTF2H5 loss contributes to increased sensitivity to DNA-damaging agents like cisplatin, a chemotherapeutic used in colorectal cancer treatment, and provides insight into the molecular basis of trichothiodystrophy and other photosensitivity disorders.
Applications include mechanistic studies of transcription-coupled NER, assessment of cancer drug sensitivity via DNA damage sensitivity assays (UV, cisplatin), and investigation of genome instability and cell cycle checkpoints. Representative assays encompass western blotting for GTF2H5 protein, RT-qPCR, immunofluorescence for TFIIH localization, NER activity assays, transcription reporter assays, and RNA-seq. The polyclonal nature allows capturing population-level heterogeneity. For further information and technical support, please contact Ascent Research.
