B7-1 CRISPR Activation Plasmid (h): sc-401971-ACT

Human CD80 (B7-1) is a costimulatory immunoglobulin superfamily ligand expressed primarily on antigen-presenting cells, where it binds CD28 and CTLA-4 on T cells to modulate activation, proliferation, and cytokine production. By shaping immunological synapse formation and integrating signals that complement TCR engagement, B7-1 influences downstream pathways controlling effector differentiation and peripheral tolerance. Dysregulated CD80 expression is implicated in aberrant immune activation and impaired tolerance mechanisms observed across autoimmune and inflammatory disorders, and it is frequently evaluated in tumor immunology as a determinant of antigen presentation capacity. In vitro, CD80 serves as a key marker and functional node in studies of dendritic cell maturation, macrophage polarization, and T cell priming.

B7-1 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous CD80 expression without altering the underlying DNA sequence.

B7-1 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the CD80 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 CD80 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous B7-1 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native CD80 locus and enabling the study of B7-1-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of B7-1 pathway restoration in tumor cells with silenced or reduced CD80 expression.

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