Scientists announced, this week, they have developed a new gene-editing technology with the potential to correct nearly 90 percent of all genetic defects, including those that cause extreme—even incurable—conditions like sickle cell anemia.
The researchers at Harvard/MIT Broad Institute developed this new technique, which they are calling “prime editing.” The technique, essentially, builds on the strong foundation of CRISPR gene editing with more precise and versatile functionality. According to the research, this technique “directly writes new genetic information into a specified DNA site.”
The traditional CRISPR-Cas9 approach uses a modified protein (Cas9) like a proverbial pair of scissors that snips parts of DNA strands. Cas9, then, can target genes in a specific place in order to, for example, disrupt a mutation.
This is significant because approximately two-thirds of known human genetic variants currently associated with diseases are of this type: the single point gene mutation. This means gene editing has definite potential to correct or to reproduce the mutation. Effectively, this technique can improve or reverse certain genetic conditions.
Building on top of that, then, prime editing combines the Cas9 method with another protein that can generate brand new DNA. Basically, this works by snipping out the afflicted strand of DNA and replaces it with an edited sequence of the targeted DNA.
A little more specifically, study co-author David Liu explains, “In many respects this first report is the beginning rather than the end of a longstanding aspiration…to be able to make any DNA change in any position of a living cell or organism including, potentially, human patients with genetic diseases.”
The Harvard/MIT Broad Institute chemist goes on to say, “With prime editing, we can now directly correct the sickle-cell anemia mutation back to the normal sequence and remove the four extra DNA bases that cause Tay Sachs disease, without cutting DNA entirely or needing DNA templates.”
Obviously, this is just the beginning of an exciting new realm of research. The team will continue to work on honing the technique, with the goal, of course, to maximize its overall efficiency. The hope is to be able to expand this efficiency to more cell types and explore any other potential effects the technique could have on these cells.