Conditional splicing system for tight control of viral overlapping genes

Area of Science:

• Molecular Biology
• Virology
• Gene Therapy

Background:

• Viral genomes often contain overlapping genes, posing challenges for developing viral-vector-based vaccines and therapies.
• Existing methods for regulating overlapping genes can lead to cytotoxicity and instability, hindering progress in gene therapy and vaccine development.

Purpose of the Study:

• To introduce and refine a novel site-specific recombinase (SSR)-mediated conditional splicing system for precise control of overlapping gene expression.
• To address challenges in viral vector engineering, including cytotoxicity and stable packaging cell line development.

Main Methods:

• Development and refinement of a "loxp-splice-loxp"-based conditional splicing system.
• Exploration of the mechanisms underlying SSR-mediated conditional splicing.
• Application of the system to adenovirus-associated virus (AAV) and human immunodeficiency virus type 1 (HIV-1).

Main Results:

• The SSR-conditional splicing system demonstrated exceptional inducibility (116,700-fold increase) with minimal background expression.
• Successful conditional expression of overlapping genes was achieved in AAV and HIV-1 vectors.
• Stable AAV producer cell lines, containing all necessary packaging genes, were established using this system.

Conclusions:

• The SSR-conditional splicing system offers a powerful tool for precisely controlling overlapping gene expression in viral vectors.
• This technology significantly advances vector engineering, paving the way for more effective and scalable viral-vector-based therapies and vaccines.
• The system holds potential for regulating other cytotoxic genes, benefiting cell engineering and gene therapy applications.