STARR-CRAAVT: A platform to identify cell type-specific regulatory elements for next-generation gene therapy.

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Adeno-associated virus (AAV) gene therapy relies on precise control of transgene expression.
• Enhancer-promoter combinations are crucial for achieving potent and cell type-specific gene expression.

Purpose of the Study:

• To introduce and validate STARR-CRAAVT, a novel screening platform for identifying enhancers in AAV vectors.
• To assess the impact of promoter type and genomic position on enhancer activity within AAVs.

Main Methods:

• Developed STARR-CRAAVT, a STARR-Seq-based platform utilizing in silico tailored sequence libraries.
• Generated candidate libraries by integrating epigenetic data and capturing genomic fragments for AAV packaging.
• Conducted in vitro proof-of-concept studies to screen enhancers and evaluate screening parameters.

Main Results:

• Identified enhancers capable of driving cell type-specific transgene expression.
• Demonstrated that promoter type is a critical factor in enhancer function.
• Showed that the position of enhancer candidates within the AAV genome significantly affects their activity.

Conclusions:

• STARR-CRAAVT is an effective platform for discovering cell type-specific enhancers for AAV gene therapy.
• Insights into enhancer function, promoter influence, and positional effects provide a blueprint for optimizing AAV vector design.