Spi-B CRISPR Activation Plasmid (h): sc-402613-ACT

SPIB encodes Spi-B, an ETS family transcription factor with prominent roles in hematopoietic lineage specification and immune cell maturation, particularly within B cell and plasmacytoid dendritic cell programs. Spi-B regulates gene networks that control antigen receptor signaling, interferon-associated responses, and transcriptional circuits governing differentiation and activation states. Altered SPIB expression or regulatory activity has been associated with dysregulated immune phenotypes and has been reported in multiple hematologic malignancy contexts, supporting its use as a molecular node for studying transcriptional rewiring. As a DNA-binding regulator, Spi-B provides a tractable entry point to interrogate promoter/enhancer logic and chromatin-dependent control of immune lineage identity.

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

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

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