Even though CRISPR genome editing tool is regarded as a revolutionary tool, one of its technical hurdles—inserting foreign DNA cassettes at genomic cut sites—remained a major challenge until an Easier version of CRISPR was developed.
In a collaborative study, Drs. Gurumurthy (Associate Professor of Developmental Neuroscience at Munroe-Meyer Institute, University of Nebraska Medical Center, USA) and Masato Ohtsuka (Associate Professor of Department of Molecular Life Sciences, School of Medicine, Tokai University, Japan) developed a method called Easi-(Efficient additions with ssDNA inserts)-CRISPR and described this method in Genome Biology journal published in May 2017.
They showed that highly popular mouse models, such as conditional knockout and reporter knock-in models, could be created at an efficiency as high as 100% by using their Easi-CRISPR method, whereas the previously used CRISPR-based methods were only about 1% or 2%, or at best about 10% efficient.
They used long single-stranded DNAs as donor cassettes, unlike the double-stranded DNA donors commonly used by the scientific community, as the dsDNA donors are typically very inefficient.
They first observed the robustness of their Easi-CRISPR platform in summer of 2016 and they posted their preliminary results at the preprint server BioRxiv, and started presenting their data at conferences, so that their method can be immediately useful to the scientific community.
Dr. Gurumurthy said, he and Dr. Ohtsuka received hundreds of inquiries about the method, following their papers. Because of such overwhelming response they posted another BioRxiv article describing step-by-step protocol of Easi-CRISPR, which is now published in Nature Protocols
Their first paper has already been accessed more than 15,000 times and cited 20 times, and it was also noted as one of the best-of-2017-genome-biology articles. Dr. Gurumurthy said, more than two dozen labs have been successful in using their method already, and more labs are adapting to it.
“For me as a scientist, it is very satisfying to see the research community’s response, and more importantly, it is very gratifying to hear that many others could reproduce the results,” he said. “Interest from the research community in Easi-CRISPR is growing very fast, and Easi-CRISPR could be an useful tool for many applications in basic research as well as translational research and therapeutic areas”.