SP-B CRISPR Activation Plasmid (m): sc-422901-ACT

Sftpb encodes surfactant protein B (SP-B), a hydrophobic pulmonary surfactant component required for packaging and spreading of phospholipids that stabilize alveolar surface tension during respiration. In mouse alveolar type II epithelial cells, SP-B is processed from a proprotein and trafficked through secretory and lamellar body pathways to support surfactant homeostasis and lung compliance. Sftpb activity is tightly linked to epithelial differentiation programs and lipid handling processes that coordinate surfactant biogenesis and turnover. Altered SP-B expression or processing is associated with disrupted surfactant function and phenotypes relevant to neonatal respiratory insufficiency, interstitial lung pathology, and susceptibility to alveolar injury in experimental models.

SP-B CRISPR Activation Plasmid (m) provides a targeted, non-destructive approach to upregulating endogenous Sftpb expression without altering the underlying DNA sequence.

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

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