CD21 CRISPR Activation Plasmid (h): sc-401352-ACT

CR2 encodes CD21, a complement receptor expressed primarily on B cells and follicular dendritic cells that binds C3d-opsonized antigens and cooperates with CD19 and CD81 to lower the threshold for B cell receptor signaling. Through this co-receptor function, CD21 integrates complement tagging with adaptive immunity, shaping antigen uptake, germinal center reactions, and antibody responses. CD21 also serves as a cellular attachment factor for Epstein–Barr virus, linking CR2 biology to pathways involved in viral entry and downstream immune activation. Dysregulated CR2/CD21 activity has been associated with altered humoral immunity and inflammatory phenotypes relevant to autoimmunity and B cell–driven disease mechanisms.

CD21 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous CR2 expression without altering the underlying DNA sequence.

CD21 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the CR2 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 CR2 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous CD21 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native CR2 locus and enabling the study of CD21-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of CD21 pathway restoration in tumor cells with silenced or reduced CR2 expression.

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