CD8-β CRISPR Activation Plasmid (h): sc-400950-ACT

CD8B encodes the CD8-β chain, a type I transmembrane glycoprotein that pairs with CD8-α to form the CD8 co-receptor on cytotoxic T lymphocytes and a subset of NK cells. By binding MHC class I and associating with the Src-family kinase LCK, CD8 enhances T cell receptor signal transduction, supports immunological synapse formation, and contributes to thymic selection and effector differentiation. CD8B expression and CD8 co-receptor function are closely tied to antigen-specific cytotoxic responses, immune surveillance, and T cell exhaustion dynamics in chronic infection and tumor microenvironments. Dysregulated CD8-associated signaling and altered CD8+ T cell states are frequently investigated in cancer immunology, autoimmunity, and primary immunodeficiency research.

CD8-β CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous CD8B expression without altering the underlying DNA sequence.

CD8-β CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the CD8B 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 CD8B transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous CD8-β expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native CD8B locus and enabling the study of CD8-β-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of CD8-β pathway restoration in tumor cells with silenced or reduced CD8B expression.

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