Targeted DNA integration in human cells without double-strand breaks using CRISPR RNA-guided transposases

Area of Science:

• Genetics
• Molecular Biology
• Biotechnology

Background:

• Traditional genome editing using CRISPR-Cas9 relies on double-strand breaks (DSBs), which can lead to unwanted mutations and limited control over integration outcomes.
• Existing methods face challenges in product purity and precision for targeted DNA modification.

Approach:

• Developed a novel system for programmable, DSB-free DNA integration in human cells using Type I CRISPR-associated transposons (CASTs).
• Optimized the QCascade complex for DNA targeting and engineered transcriptional activators via TnsC recruitment.
• Screened homologous CAST systems, identified an active homolog from *Pseudoalteromonas*, and enhanced integration efficiencies.
• Discovered that bacterial ClpX significantly boosts genomic integration, likely by aiding CAST complex disassembly.

Key Points:

• Demonstrated successful adaptation and optimization of CAST systems for human cell applications.
• Achieved enhanced DNA integration efficiency through protein engineering and screening of bacterial homologs.
• Identified ClpX as a crucial factor for increasing genomic integration rates.

Conclusions:

• Established a robust, DSB-free genome engineering platform using CRISPR-associated transposons in human cells.
• This work provides a foundation for advanced genome engineering applications with improved safety and precision.
• Highlights the potential of reconstituting complex bacterial systems in eukaryotic cells for novel biotechnological tools.