FcRH5 CRISPR Activation Plasmid (h): sc-413461-ACT

FCRL5 (FcRH5) is a B cell–restricted immunoregulatory receptor in the Fc receptor–like family that modulates signaling thresholds during B cell activation and differentiation. Through cytoplasmic immunoreceptor tyrosine-based motifs, FcRH5 influences phosphorylation-dependent pathways linked to B cell receptor signaling, cytokine responsiveness, and immune homeostasis. Its expression is enriched across mature B cell subsets and is commonly evaluated as a marker of B cell state transitions within secondary lymphoid tissues. Dysregulated FCRL5 expression has been associated with altered B cell function in chronic immune stimulation contexts and B cell–derived malignancies, supporting its use in mechanistic studies of B cell biology and tumor immunology.

FcRH5 CRISPR Activation Plasmid (h) provides a targeted, non-destructive approach to upregulating endogenous FCRL5 expression without altering the underlying DNA sequence.

FcRH5 CRISPR Activation Plasmid (h) is a three-plasmid synergistic activation mediator (SAM) system engineered for highly efficient, site-specific transcriptional upregulation of the FCRL5 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 FCRL5 transcriptional start site, where VP64, p65, and HSF1 act in concert to recruit transcriptional machinery and drive upregulation of endogenous FcRH5 expression. Unlike nuclease-active Cas9, dCas9 does not introduce double-strand breaks or modify the genomic sequence, preserving the native FCRL5 locus and enabling the study of FcRH5-dependent transcriptional responses at the endogenous locus, making it a valuable tool for functional studies, target gene identification, and the modeling of FcRH5 pathway restoration in tumor cells with silenced or reduced FCRL5 expression.

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