New research on "Cell Blockbuster" DNA repair has promoted the development of CRISPR-Cas9 gene editing technology and the pilot editing technology developed by the team of gene editing giant Liu Ruqian

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Author: Daisy

On October 20, researchers published research in Cell showed that Editas Medicine, a gene-editing biotechnology company based on CRISPR technology co-founded by founder Chinese biologist Zhang Feng and others, detailed a new method called Repair-seq. To repair DNA, cells use many different mechanisms, each involving a set of genes that work together in different pathways. The researchers are now collaborating to explore the contribution of these pathways to repairing specific DNA damage by simultaneously analyzing how hundreds of individual genes affect mutations produced at the damaged site using Payage-seq. Researchers can then generate models of the mechanisms of DNA repair and understand how these mechanisms affect genome editing. They are applied to CRISPR-Cas9, one of the most commonly used genome editing methods. David Liu's team developed a genome editing system called pilot editing, and the researchers also applied Repair-seq to improve their genome editing technology, making it ultimately a more widely applicable and more accurate genome editing technology.

The ability to edit genomes by altering dna sequences within living cells is powerful for research and holds great promise in disease treatment. However, existing genome editing techniques often lead to unnecessary mutations, or simply cannot introduce any changes. These problems prevent the field from reaching its full potential.

On October 20, researchers published an article in Cell titled "Mapping the genetic landscape of DNA double-strand break repair."

DOI:https://doi.org/10.1016/j.cell.2021.10.002

Now, Princeton University Lab Researcher Britt Adamson is collaborating with researchers in the lab of Whitehead Institute member, MIT Biology Professor, Howard Hughes Institute of Medicine Fellow Jonathan Weissman, and Cecilia Cotta Ramusino,000 researchers previously at Editas Medicine (co-founded by Feng Zhang and others at MIT, CRISPR, the first IPO in the field of gene editing), details a new method called Repair-seq, which details how genome editing tools work.

Britt Adamson, senior author of the study and assistant professor in Princeton's Department of Molecular Biology and Lewis Sigler Institute for Integrated Genomics, said: "We have long known that the mechanisms that repair broken DNA are critical for genome editing, because to change the DNA sequence, it must first be destroyed. But these processes are extremely complex and are often difficult to sort out. ”

To repair DNA, cells use many different mechanisms, each involving a set of genes that work together in different pathways. Repair-seq allows researchers to explore the contribution of these pathways to repairing specific DNA damage by simultaneously analyzing how hundreds of individual genes affect mutations produced at damaged sites. Researchers can then generate models of the mechanisms of DNA repair and understand how these mechanisms affect genome editing. Adamson and colleagues applied their method to crispr-Cas9, one of the most commonly used methods of genome editing— the use of the bacterial Cas9 nuclease to cleave two strands of a double-stranded DNA molecule, causing damage called a double-strand break.

Lead author Jeffrey Hussmann, who led the work while working as a postdoctoral researcher in Jonathan Weissman's lab, said: "Editing with double-strand breaks has long been a major task for genome editing, but making the expected changes without unnecessary mutations is a huge challenge. We began to understand the mechanisms behind inducing as many mutations as possible, and inferred that this would help us optimize the system. ”

The Repair-seq experiment produced a large amount of data. Under Hussmann's leadership, after analyzing these data, a map of how different DNA repair pathways are associated with specific types of Cas9-induced mutations was mapped. Based on the field's rich research history, Hussmann's analysis elucidates known pathways and identifies new pathways that together highlight the enormous complexity and myriad systems involved in double-strand fracture repair. The deep data found in the study is now posted on an online portal that others can use to query DNA repair genes and pathways.

In addition, a team led by Professor David Liu of the Broad Institute at MIT and Harvard University has developed a genome editing system called "prime editing, which doesn't rely on generating double-strand breaks." "Prime editing" efficiencies vary by cell type and target, but the researchers suspect that identifying the DNA repair pathways involved may help identify pathways for improvement. With this in mind, Adamson and Hussmann teamed up with Liu and colleagues to study "prime editing" using Paypair-seq.

Adamson said: "Collaboration is a huge benefit. For us, it was a wonderful experience of collaborative and team-oriented science. ”

The researchers found that the ability to obtain the intended edits through "prime editing" was influenced by proteins in dna mismatch repair pathways. They then showed that inhibiting or circumventing this pathway significantly improved the efficiency and accuracy of "prime editing" results, making "prime editing" a more widely applicable genome editing technique.

"Working with Britt, Jonathan and their lab is the perfect combination of basic science, tool application and technology development, a true testament to the power of multidisciplinary collaboration," Liu says. ”

Importantly, the study also shows how Repair-seq can be used to improve other genome editing techniques. In fact, the collaborating researchers have applied it to a third genome editing system, which was also developed by Liu's team of scientists. The results of this study were recently published in the journal Nature Biotechnology.

John Doench, director of research and development for the Gene Perturbation Project at broad research, was not involved in the study, but said: "Repair-seq is the perfect combination of technical insight and biological insight. ”

He added: "What a wonderful example of collaboration for this new study from prime editing! ”

In the future, the team will continue to improve the platform and apply it to other genome editing technologies.

"We see Copepar-seq as a tool that allows you to learn more about the work that genome editing does inside cells and then quickly assess, 'Is this an area where I can find ways to help improve the design principles of this tool?'" said Adamson. 'We are very excited to explore future applications. ”

The studies were funded by the National Institutes of Health, the Howard Hughes Institute of Medicine, the Searle Scholars Program, the National Science Foundation, the Damon Runeon Cancer Research Foundation, the China Scholarship Council, and the National Cancer Institute.

Resources:

https://phys.org/news/2021-10-tool-ways-crispr-gene-editing-method.html

Note: This article is intended to introduce the progress of medical research and cannot be used as a reference for treatment options. For health guidance, please visit a regular hospital.

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