Siglec-9 CRISPR Activation Plasmid (h): sc-406675-ACT

SIGLEC9 encodes Siglec-9, a sialic acid–binding immunoglobulin-like lectin predominantly expressed on neutrophils, monocytes, and subsets of NK cells, where it functions as an inhibitory receptor that dampens cellular activation. Through its cytoplasmic ITIM motifs, Siglec-9 recruits phosphatases such as SHP-1/SHP-2 to modulate signaling downstream of immune receptors, shaping processes including cytokine production, degranulation, phagocytosis, and oxidative burst. By recognizing sialylated ligands on host or altered cells, Siglec-9 contributes to immune homeostasis and the regulation of inflammation. Dysregulated Siglec-9 signaling has been implicated in pathological immune suppression and chronic inflammatory contexts, supporting its use as a marker and mechanistic node in immunology and tumor–immune interaction studies.

Siglec-9 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous SIGLEC9 expression without altering the underlying DNA sequence.

Siglec-9 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the SIGLEC9 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 SIGLEC9 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous Siglec-9 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native SIGLEC9 locus and enabling the study of Siglec-9-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of Siglec-9 pathway restoration in tumor cells with silenced or reduced SIGLEC9 expression.

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