A Digital PCR-Based Method for Efficient and Highly Specific Screening of Genome Edited Cells

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• CRISPR and TALEN gene editing technologies require accurate detection methods for research and therapeutic applications.
• Current mismatch cleavage assays (T7E1, Surveyor) are prone to false positives and require substantial starting material.
• There is a need for sensitive, specific, and rapid assays to validate gene editing outcomes.

Purpose of the Study:

• To introduce droplet digital PCR (ddPCR) as a superior alternative for detecting and quantifying gene editing alterations.
• To demonstrate ddPCR's ability to differentiate homozygous from heterozygous mutations with high precision and sensitivity.
• To validate gene editing of NODAL and SFRP1 using TALENs and CRISPR/Cas systems.

Main Methods:

• Utilized droplet digital PCR (ddPCR) for precise quantification of gene editing events.
• Employed TALENs and a modified CRISPR/Cas plasmid for gene editing.
• Assessed ddPCR's capability to distinguish homozygous and heterozygous mutations.
• Evaluated ddPCR for assessing TALEN-based strategy efficiency.

Main Results:

• ddPCR accurately distinguished homozygous from heterozygous mutations with high precision and sensitivity.
• The ddPCR assay successfully detected gene editing alterations in NODAL and SFRP1.
• ddPCR effectively assessed the efficiency of different TALEN-based gene editing strategies.
• Demonstrated the utility of a modified CRISPR/Cas plasmid for streamlined gene editing.

Conclusions:

• ddPCR provides a sensitive, specific, and streamlined method for gene editing validation.
• ddPCR overcomes limitations of traditional mismatch cleavage assays, reducing false positives.
• This ddPCR-based screening approach enhances the utility of CRISPR and TALEN gene editing technologies.