SC CRISPR Activation Plasmid (h): sc-402459-ACT

Polymeric immunoglobulin receptor (PIGR) encodes the secretory component (SC), a transmembrane receptor that binds dimeric IgA and pentameric IgM at the basolateral surface of epithelial cells and transports them across the epithelium for mucosal secretion. During transcytosis, SC is proteolytically released and remains associated with secretory IgA, enhancing immune exclusion and protecting antibodies from proteolysis in mucosal environments. PIGR expression is regulated by inflammatory and cytokine-driven signaling, including NF-κB and JAK/STAT pathways, linking epithelial innate responses to adaptive mucosal immunity. Dysregulated PIGR/SC biology is studied in barrier dysfunction and chronic inflammation, with implications for infection susceptibility and epithelial tumor microenvironment interactions.

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

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

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