StAR CRISPR Activation Plasmid (h): sc-400961-ACT

Human STAR encodes the steroidogenic acute regulatory protein (StAR), a mitochondria-associated factor that mediates the rate-limiting delivery of cholesterol from the outer to the inner mitochondrial membrane for steroid hormone biosynthesis. This transport step is essential for pregnenolone production by CYP11A1 and integrates with cAMP/PKA-driven steroidogenic signaling in adrenal and gonadal cells. Disruption or dysregulation of StAR alters mitochondrial cholesterol handling and downstream steroidogenesis, linking STAR to endocrine and reproductive phenotypes and providing a mechanistic entry point for studying mitochondrial lipid trafficking and steroidogenic metabolism. STAR is therefore frequently investigated in models of adrenal and gonadal function, stress signaling, and metabolic control of hormone production.

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

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

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