Nuclease dead Cas9 is a programmable roadblock for DNA replication

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Studying interactions between DNA-bound molecular machines is challenging due to limited experimental tools.
• Understanding how these machines collide and affect DNA processes is crucial for molecular biology.

Purpose of the Study:

• To develop a novel, targetable protein-DNA roadblock for in vitro studies.
• To investigate the mechanisms of enzymatic activities on DNA substrates when encountering obstacles.

Main Methods:

• Repurposing a catalytically inactivated Cas9 (dCas9) construct as a protein-DNA roadblock.
• Utilizing a dCas9-guideRNA complex for specific DNA targeting.
• Demonstrating replication fork arrest in vitro using the dCas9 roadblock.

Main Results:

• The dCas9-guideRNA complex successfully functions as a generic and targetable DNA roadblock.
• Replication forks from viral, bacterial, and eukaryotic sources were arrested in vitro by the dCas9 roadblock.
• The study validates the utility of dCas9 as a tool for studying DNA-associated processes.

Conclusions:

• The inactivated Cas9 (dCas9) serves as a versatile tool for creating targeted DNA roadblocks.
• This method facilitates the study of molecular machine collisions and their impact on DNA replication.
• The developed dCas9 roadblock system offers a new avenue for in vitro mechanistic investigations in molecular biology.