Nov 16, 2017

Genetic engineering mechanism visualized

 

Researchers at Kanazawa University and the University of Tokyo report in Nature Communications the visualization of the dynamics of 'molecular scissors' -- the main mechanism of the CRISPR-Cas9 genetic-engineering technique.

 

Overview of the press release

One of the techniques used in genetic engineering -- the process of artificially modifying the genome of a living organism -- involves the so-called CRISPR-Cas9 nuclease system. Using this system, a cell's DNA can be cut at a desired site, where genes can be deleted or added. Selection of the site to be cut is done by a 'guide RNA' molecule bound to the Cas9 protein. Now, a team of researchers led by Mikihiro Shibata from Kanazawa University and Osamu Nureki from the University of Tokyo has visualized the dynamics of the CRISPR-Cas9 complex, in particular how it cuts DNA, providing valuable insights into the CRISPR-Cas9-mediated DNA cleavage mechanism.

For their visualization studies, the scientists used high-speed atomic-force microscopy (HS-AFM), a method for imaging surfaces. A surface is probed by moving a tiny cantilever over it; the force experienced by the probe can be converted into a height measure. A scan of the whole surface then results in a height map of the sample. The high-speed experimental set-up of Shibata and colleagues enabled extremely fast, repeated scans -- convertible into movies -- of the biomolecules taking part in the molecular scissoring action.

Figure:HS-AFM movie of DNA cleavage by CRISPR-Cas9
The HNH nuclease domain in an active conformation is indicated by a magenta arrow.

 

 

For more information, please visit the website of Kanazawa University.

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