SR-A CRISPR Activation Plasmid (h): sc-401898-ACT

Human MSR1 encodes scavenger receptor class A (SR-A), a pattern-recognition receptor predominantly expressed on macrophages and other myeloid cells that binds modified lipoproteins, apoptotic cells, and diverse microbial ligands. SR-A contributes to innate immune recognition and phagocytic clearance while shaping inflammatory signaling networks, including crosstalk with Toll-like receptor pathways and cytokine programs. Through its role in uptake of oxidized LDL and cellular debris, MSR1 is widely studied in lipid handling, foam cell biology, and macrophage polarization. Dysregulated MSR1 activity and expression have been associated with chronic inflammatory settings and cardiometabolic disease mechanisms, providing a molecular entry point for dissecting immunometabolic regulation.

SR-A CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous MSR1 expression without altering the underlying DNA sequence.

SR-A CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the MSR1 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 MSR1 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous SR-A expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native MSR1 locus and enabling the study of SR-A-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of SR-A pathway restoration in tumor cells with silenced or reduced MSR1 expression.

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