Related Experiment Video
Updated: Jun 25, 2025

Enhanced Genome Editing with Cas9 Ribonucleoprotein in Diverse Cells and Organisms
Published on: May 25, 2018
Rapid DNA unwinding accelerates genome editing by engineered CRISPR-Cas9
Amy R Eggers1, Kai Chen1, Katarzyna M Soczek2
1Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
Engineered Geobacillus stearothermophilus Cas9 (GeoCas9) with mutations in its wedge domain dramatically enhances genome editing in human cells. This improvement stems from accelerated DNA unwinding, offering a new strategy for improving CRISPR-Cas9 technology.
Area of Science:
- Molecular Biology
- Biotechnology
- Genetics
Background:
- Thermostable CRISPR-associated (Cas9) enzymes offer potential for enhanced genome editing due to longer protein stability.
- The Geobacillus stearothermophilus Cas9 (GeoCas9) enzyme showed limited activity in human cells, hindering its application.
- Mutations in the wedge (WED) domain are key to overcoming limitations in Cas9 orthologs.
Purpose of the Study:
- To investigate the mechanism behind the enhanced genome-editing activity of laboratory-evolved GeoCas9 variants.
- To elucidate the structural and functional role of the WED domain in GeoCas9 activity.
- To establish a general strategy for improving other Cas9 orthologs for genome editing.
Main Methods:
- Laboratory evolution of GeoCas9 to enhance its activity in human cells.
- Cryoelectron microscopy (cryo-EM) to determine the structures of wild-type and improved GeoCas9 (iGeoCas9).
- Biochemical assays to analyze DNA unwinding kinetics and substrate capture under varying magnesium conditions.
Main Results:
- Laboratory-evolved GeoCas9 (iGeoCas9) exhibited over 100-fold higher genome-editing levels compared to the wild-type enzyme.
- Cryo-EM structures revealed extended contacts between the iGeoCas9 WED domain and DNA substrates.
- iGeoCas9 demonstrated accelerated DNA unwinding, facilitating substrate capture in magnesium-restricted mammalian cell conditions.
Conclusions:
- The Cas9 WED domain plays a crucial role in DNA unwinding, which is essential for efficient genome editing.
- Accelerated target DNA unwinding is a key factor in dramatically improving Cas9-induced genome-editing activity.
- This study provides a generalizable strategy for engineering other Cas9 orthologs to enhance their genome-editing capabilities.
More Related Videos
10:07A Standard Methodology to Examine On-site Mutagenicity As a Function of Point Mutation Repair Catalyzed by CRISPR/Cas9 and SsODN in Human Cells
Published on: August 25, 2017
11:35Selection-dependent and Independent Generation of CRISPR/Cas9-mediated Gene Knockouts in Mammalian Cells
Published on: June 16, 2017
Related Concept Videos
CRISPR
Homologous Recombination
CRISPR and crRNAs
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
Conservative Site-specific Recombination and Phase Variation
The recognition sites for Cre recombinase called LoxP...