SP-D CRISPR Activation Plasmid (h): sc-401572-ACT

Human SFTPD encodes surfactant protein D (SP-D), a collagen-containing C-type lectin (collectin) secreted primarily by alveolar type II cells and airway epithelium that binds pathogen- and damage-associated glycans to promote opsonization and agglutination. SP-D modulates innate immune signaling by influencing complement-related processes and regulating inflammatory tone in the lung, including effects on macrophage activation and cytokine production. Through these activities it contributes to surfactant homeostasis and mucosal defense at the air–liquid interface. Altered SFTPD expression or SP-D function has been linked to dysregulated pulmonary inflammation and susceptibility to respiratory disease phenotypes, making it a useful target for mechanistic studies in airway and alveolar models.

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

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

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