XPA CRISPR Activation Plasmid (h): sc-401483-ACT

Human XPA encodes a core DNA damage recognition factor in the nucleotide excision repair (NER) pathway that verifies helix-distorting lesions and coordinates recruitment of TFIIH, RPA, and ERCC1–XPF to enable dual incision and repair synthesis. By scaffolding repair complexes at UV photoproducts and bulky chemical adducts, XPA helps preserve genome integrity during replication and transcription. Disruption or reduced activity of XPA compromises NER capacity, increasing mutational burden and cellular sensitivity to genotoxic stress. XPA dysfunction is linked to xeroderma pigmentosum group A and is frequently leveraged in studies of DNA repair deficiency, mutagenesis, and stress-response signaling.

XPA CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous XPA expression without altering the underlying DNA sequence.

XPA CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the XPA locus in human cell lines. The system is built around a catalytically inactive Cas9 (dCas9) carrying two inactivating mutations (D10A and N863A) that eliminate nuclease activity while preserving DNA binding. This dCas9 is fused to VP64, a potent transcriptional activator, and is co-expressed with a blasticidin resistance gene for selection. The second plasmid encodes the MS2-p65-HSF1 fusion protein, a secondary activator complex that works in concert with dCas9-VP64, alongside a hygromycin resistance gene. The third plasmid encodes a target-specific 20 nt sgRNA fused to two MS2 RNA aptamers that recruit the MS2-p65-HSF1 complex to the activation site, accompanied by a puromycin resistance gene. The three plasmids are delivered at a 1:1:1 mass ratio for balanced expression of all system components.

Once assembled at the target locus, the SAM complex binds within approximately 200 bp upstream of the XPA transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous XPA expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native XPA locus and enabling the study of XPA-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of XPA pathway restoration in tumor cells with silenced or reduced XPA expression.

For Research Use Only. Not Intended for Diagnostic or Therapeutic Use.