Nibrin CRISPR Activation Plasmid (h): sc-401723-ACT

Human NBN encodes nibrin, an essential component of the MRN complex (MRE11–RAD50–NBN) that senses DNA double-strand breaks and coordinates damage signaling. Nibrin supports ATM activation, DNA end tethering, and pathway choice between homologous recombination and non-homologous end joining, thereby promoting genome stability and proper S-phase checkpoint control. Disruption of NBN function is linked to impaired double-strand break repair, chromosomal instability, and hypersensitivity to genotoxic stress, with relevance to Nijmegen breakage syndrome and cancer predisposition biology. These properties make NBN a widely used node for interrogating DNA damage response pathways, replication stress, and genome maintenance mechanisms in human cells.

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

Nibrin CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the NBN 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 NBN transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous Nibrin expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native NBN locus and enabling the study of Nibrin-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of Nibrin pathway restoration in tumor cells with silenced or reduced NBN expression.

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