CD4 CRISPR Activation Plasmid (h): sc-400237-ACT

Human CD4 encodes a type I transmembrane glycoprotein predominantly expressed on T helper lymphocytes and subsets of dendritic cells and macrophages, where it functions as a coreceptor that stabilizes TCR–MHC class II interactions and enhances proximal signaling through LCK. CD4-dependent signaling influences T cell activation, differentiation, and cytokine programs that shape adaptive immune responses, including pathways governing antigen presentation and immune synapse formation. Dysregulated CD4 expression or function is linked to altered immune homeostasis in inflammatory and autoimmune contexts and is central to studies of host–pathogen interactions given its role in immune cell tropism. As a cell-surface lineage marker, CD4 is also widely used to stratify immune subsets in immuno-oncology and systems immunology research.

CD4 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous CD4 expression without altering the underlying DNA sequence.

CD4 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the CD4 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 CD4 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous CD4 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native CD4 locus and enabling the study of CD4-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of CD4 pathway restoration in tumor cells with silenced or reduced CD4 expression.

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