Transient Retrovirus-Based CRISPR/Cas9 All-in-One Particles for Efficient, Targeted Gene Knockout

Area of Science:

• Molecular Biology
• Gene Editing Technologies
• Retroviral Vector Development

Background:

• CRISPR/Cas9 is a powerful gene editing tool but long-term expression of its enzymes can cause cytotoxicity.
• Existing transient expression methods for CRISPR/Cas9 may have limitations in efficiency and safety.
• Developing safer and more efficient gene editing delivery systems is crucial for therapeutic applications.

Purpose of the Study:

• To develop non-integrating retrovirus-based particles for transient CRISPR/Cas9 delivery.
• To achieve targeted gene knockout with reduced cytotoxicity compared to constitutive expression.
• To enable efficient and dose-controlled delivery of CRISPR/Cas9 components.

Main Methods:

• Utilized gammaretroviral packaging machinery to create all-in-one retroviral particles.
• Delivered Streptococcus pyogenes Cas9 (SpCas9) mRNA and single-guide RNA transcripts transiently.
• Assessed gene disruption efficiency in various cell types, including primary cells.

Main Results:

• Efficient disruption of a surrogate reporter gene and endogenous genes (CXCR4, TP53) was achieved.
• Transient particle knockout efficiencies reached 52%-80% of integrating vector efficiencies.
• Transient SpCas9 delivery prevented cytotoxicity and cell cycle arrest observed with stable overexpression.

Conclusions:

• Non-integrating retrovirus-based particles offer an efficient method for transient CRISPR/Cas9 delivery.
• This approach mitigates risks associated with long-term DNA-modifying enzyme expression.
• The developed system allows for dose-controlled gene editing with potential clinical relevance.