OST48 CRISPR Activation Plasmid (h): sc-403323-ACT

DDOST encodes OST48, a core subunit of the oligosaccharyltransferase (OST) complex in the rough endoplasmic reticulum that catalyzes co-translational N-linked glycosylation of nascent secretory and membrane proteins. By supporting glycoprotein maturation and quality control, OST48 links protein biogenesis to ER proteostasis, unfolded protein response signaling, and ER-associated degradation pathways. Altered N-glycosylation can perturb receptor trafficking, cell–cell communication, and immune recognition, and DDOST dysregulation has been investigated in contexts where glycoproteome remodeling and ER stress are prominent features. As a housekeeping component of the OST machinery, DDOST is frequently used to probe how glycosylation capacity influences pathway signaling and cellular fitness.

OST48 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous DDOST expression without altering the underlying DNA sequence.

OST48 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the DDOST 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 DDOST transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous OST48 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native DDOST locus and enabling the study of OST48-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of OST48 pathway restoration in tumor cells with silenced or reduced DDOST expression.

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