Fibrillarin CRISPR Activation Plasmid (h): sc-400741-ACT

FBL encodes fibrillarin, an essential nucleolar methyltransferase that catalyzes 2′-O-ribose methylation of pre-rRNA within box C/D snoRNP complexes, supporting accurate rRNA processing and ribosome biogenesis. Through its roles in nucleolar organization and coordination of RNA modification with transcriptional and translational capacity, fibrillarin contributes to fundamental proteostasis and cell growth programs. Altered nucleolar activity and dysregulated ribosome production, processes in which FBL is a core component, are frequently linked to oncogenic stress responses and other diseases characterized by disrupted RNA metabolism. As a conserved hub in RNA processing pathways, FBL is widely used as a marker and mechanistic entry point for studying nucleolar function and ribonucleoprotein assembly.

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

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

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