Scientists capture images of gene-editing enzymes in action

For the first time, scientists have captured high-resolution, three-dimensional images of an enzyme in the process of precisely cutting DNA strands.

The images-captured using a technique called cryogenic electron microscopy, or cryo-EM-reveal new information about a gene-editing tool called CRISPR-Cas9 works, which may help researchers Genoa.

The findings-published today in Nature Structural and Molecular Biology-Developed for future treatment and prevention of a human disease caused by DNA mutations, from cancer to cystic fibrosis and Huntington disease.

"Said UBC researcher Sriram Subramaniam, who led the cryo-EM studies. "These images provide us with invaluable information to improve the efficiency of the gene-editing process so that we can hopefully correct the disease-causing DNA mutations more quickly and precisely in the future."

CRISPR, short for CRISPR-Cas9, is a gene-editing tool in which the enzyme Cas9 acts like a pair of molecular scissors, capable of cutting strands of DNA. Once the enzyme makes cuts in DNA at specific sites, insertions and edits can be made, hence changing the DNA sequence.

To understand the sequence of events involved in the process, Subramaniam and colleagues used cryo-EM technology to image the Cas9 enzyme at work. Uncategorized Unprecedented Glimpses of the Stepwise Molecular Motions That Occur in the Course of DNA Cutting by Cas9, including a snapshot of the cut DNA still attached to the enzyme immediately before release.

"One of the main hurdles preventing the development of better gene-editing tools," said the study's co-senior author, University of Illinois researcher Miljan Simonovic. "But now we have a much clearer picture, and we can see the major areas of the enzyme move during this reaction."

The Subramaniam laboratory was the first to achieve atomic resolution imaging of proteins and protein-bound drugs using cryo-EM. In the last few years, they have been used to visualize a variety of proteins including metabolic enzymes, brain receptors, and DNA-protein complexes.

The National Cancer Institute, National Institutes of Health grants, the UIC Center for Clinical and Translational Sciences, and the Canada Excellence Research Chair position awarded to Subramaniam.

As the Canada Excellence Research Chair in Precision Cancer Drug Design, Subramaniam Direct to a Laboratory Focus on Transformative Discoveries in Cancer, Neuroscience and Infectious Disease. Xing Zhu, the study's first author, and co-author Sagar Chittori are members of the Subramaniam laboratory at UBC.