A team of researchers has developed a method that they say can improve the accuracy of CRISPR gene-editing technology by 50-fold.
They said that the method can easily be adopted by any of the technology's formats.
Improving The Accuracy Of CRISPR
The new approach adds a short tail to the guide RNA so that it folds back and binds onto itself, creating a shape similar to that of a hairpin. This way, the guide RNA creates a lock that is difficult to remove even if only a single base pair is incorrect in a DNA sequence inspected for a potential cut.
However, because the guide RNA would still prefer to bind to DNA, the correct combination of DNA would unlock it.
"CRISPR is generally incredibly accurate, but there are examples that have shown off-target activity, so there's been broad interest across the field in increasing specificity," stated Charles Gersbach, an associate professor of biomedical engineering at Duke University. "But the solutions proposed thus far cannot be easily translated between different CRISPR systems."
Gersbach added that their proposed approach is a simple and straightforward solution that took them years to demonstrate, but it works. The hairpin method can effectively prevent off-tangent activity and it can be applied any kind of CRISPR system because it modifies the guide RNA.
"What's common to all CRISPR systems is the guide RNA, and these short RNAs are much easier to engineer," added Dewran Kicak, a Ph.D. student who was also involved in the study.
In the paper published in the journal Nature Biotechnology, the researchers demonstrated how the method increased the accuracy of the CRISPR gene-editing technology. In their experiments, the team claims that the new method increased the accuracy of cuts made in human cells by an average of 50-fold across several different CRISPR systems. In one case, the new method improved the accuracy by 200-fold.
Their next step is to see how many CRISPR variants will work with their technique. The team also wants to fully understand how the locking mechanism works to see if there will be differences across CRISPR variants.
The team also wants to test the new method on an animal model of the disease.