PU.1/Spi1 Lentiviral Activation Particles (h): sc-400547-LAC

SPI1 encodes the ETS-family transcription factor PU.1 (Spi1), a lineage-determining regulator of hematopoietic differentiation that coordinates myeloid and B cell development. PU.1 binds ETS motifs to control programs involved in innate immune signaling, antigen presentation, and phagocyte function, integrating cues from cytokine/JAK-STAT, NF-κB, and Toll-like receptor pathways. Its dosage-sensitive activity shapes chromatin accessibility and transcriptional networks governing progenitor commitment and macrophage, neutrophil, and dendritic cell maturation. Dysregulated SPI1 expression or activity is implicated in hematologic malignancies and immune dysfunction, making it a key node for studying leukemogenic transcriptional circuitry and inflammatory gene regulation.

PU.1/Spi1 Lentiviral Activation Particles (h) address this need by packaging the complete synergistic activation mediator (SAM) transcriptional activation system into transduction-ready, high-titer lentiviral particles, enabling efficient SPI1 upregulation across a broader range of human cell types.

PU.1/Spi1 Lentiviral Activation Particles (h) deliver all functional components of the synergistic activation mediator (SAM) system via lentiviral transduction. The system comprises three particle preparations co-transduced into target cells: one encoding catalytically inactive dCas9 (D10A and N863A mutations) fused to the VP64 transactivation domain with a blasticidin resistance gene; one encoding the MS2-p65-HSF1 fusion protein with a hygromycin resistance gene; and one encoding a target-specific 20 nt sgRNA fused to two MS2 RNA aptamers with a puromycin resistance gene. Following lentiviral transduction and genomic integration of the expression cassettes, the SAM components are stably expressed and assemble at the target locus within the proximal promoter region upstream of the SPI1 transcriptional start site, where VP64, p65, and HSF1 act cooperatively to recruit endogenous transcriptional machinery and drive sustained upregulation of endogenous PU.1/Spi1 expression. The use of nuclease-inactive dCas9 avoids the introduction of double-strand DNA breaks and preserves the native SPI1 genomic locus and regulatory architecture.

The lentiviral format offers several practical advantages: stable genomic integration supports heritable activation across cell divisions; high-titer particle preparations eliminate the need for in-house viral production; and compatibility with primary, non-dividing, and transfection-resistant cell types expands experimental accessibility. Successful transduction can be confirmed and enriched through triple antibiotic selection using puromycin, hygromycin, and blasticidin.

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