Ig J Chain CRISPR Activation Plasmid (h): sc-403642-ACT

Human JCHAIN encodes the immunoglobulin J chain, a small secreted polypeptide required for polymerization of IgA and IgM and for formation of dimeric IgA and pentameric IgM. Ig J Chain supports assembly and stability of multimeric antibodies and enables interaction with the polymeric immunoglobulin receptor (PIGR), promoting transepithelial transport of secretory immunoglobulins and mucosal immune defense. Expression is tightly linked to B cell differentiation into antibody-secreting plasma cells and coordinated with unfolded protein response and secretory pathway programs that accommodate high immunoglobulin output. Dysregulated JCHAIN expression is used as a marker of plasma cell states and is studied in contexts including immunodeficiency, chronic inflammation, and B cell/plasma cell neoplasms.

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

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

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