SPLICER: Small Molecule-Inducible Gene Expression Switches

Enables Ligand-Inducible Regulation of Gene Expression or Knockdown

This small molecule-inducible gene expression based on riboswitches (SPLICER) enables precise, drug-responsive control of gene expression for safer and more flexible gene and cell therapies. In mammalian cells, alternative splicing greatly expands the diversity of RNA sequences. These can be incorporated into transcript isoforms. From a synthetic biological standpoint, alternative splicing is usable as a regulatory tool to control gene expression for various applications. Precise regulation of therapeutic gene activity is critical, as uncontrolled expression can cause toxicity, immune reactions, or loss of efficacy. Currently, available gene delivery system, such as AAV and lentiviral vectors, rely on constitutive or tissue-specific promoters, which lack the ability to dynamically adjust gene expression, while existing inducible systems are often bulky, leaky, or immunogenic.

Researchers at the University of Florida have developed a ligand-inducible alternative splicing platform using engineered RNA aptamers to control gene expression in response to small-molecule drugs. This modular approach enables tunable, reversible, and highly specific gene regulation, offering broad potential for applications in gene therapy, cell engineering, and research.

Application

Ligand-responsive RNA switches enable precise, drug-controlled activation or silencing of therapeutic genes, RNAs, or genome editors for safer and more flexible gene and cell therapies

Advantages

• Allows on-demand, reversible gene expression by administering a specific small molecule, reducing off-target effects and toxicity
• Compact and modular design, integrating easily into a wide range of viral vectors and gene therapy platforms
• Versatile control of proteins, microRNAs, interfering RNAs, and CRISPR/Cas components for broad research and therapeutic applications
• Enables gene expression tailored to specific cell types, disease states, or external triggers
• Provides low background activity in the absence of ligand, overcoming limitations of older inducible systems

Technology

The SPLICER platform uses ligand-responsive alternative splicing cassettes embedded within transgenes or endogenous genes. These cassettes contain engineered exons and introns with aptamer sequences that bind specific small molecules. Upon ligand binding, the aptamer undergoes a conformational change, triggering exon skipping or inclusion and thereby controlling mRNA processing. This switch can regulate the production of full-length or truncated proteins, enable or disable RNA interference, or modulate other gene functions. The system is compatible with viral delivery (AAV, lentivirus) and can be tailored for tissue specificity or environmental responsiveness, providing a powerful tool for safer, more effective gene therapies and research applications.