PA28β CRISPR Activation Plasmid (h): sc-403643-ACT

PSME2 encodes PA28β, a core subunit of the PA28 (11S) proteasome activator complex that binds the 20S proteasome and promotes ubiquitin-independent peptide processing. By accelerating proteasomal turnover and shaping peptide repertoires, PA28β contributes to antigen processing and MHC class I presentation, linking proteostasis to immune surveillance. This activity intersects with interferon-responsive pathways, oxidative stress handling, and regulation of protein quality control in the cytosol and nucleus. Dysregulated proteasome activation and antigen presentation have been associated with inflammatory signaling states and tumor immunobiology, making PSME2 a useful node for mechanistic studies in these contexts.

PA28β CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous PSME2 expression without altering the underlying DNA sequence.

PA28β CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the PSME2 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 PSME2 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous PA28β expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native PSME2 locus and enabling the study of PA28β-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of PA28β pathway restoration in tumor cells with silenced or reduced PSME2 expression.

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