Experts from Broad Institute of Harvard and MIT and partners continue to
improve gene editing. With a new super-precise version of CRISPR, the
researchers have boosted its accuracy by engineering enzymes that can
accurately target DNA without introducing as many unwanted mutations. Their
findings are reported in Nature Biotechnology.
To detect unwanted DNA edits than may cause harm, researchers conduct full
genome sequencing, but it is a long and expensive process. To address this,
the experts developed new methods to find off-target mutations in bacteria
and human cells without the need for full genome sequencing. One of the
devised methods entails insertion of base editors into bacteria and then
tested for resistance to an antibiotic drug. The higher the frequency with
which bacterial cells became resistant, the more active the base editor was
in mutating the DNA in resistance genes.
The team used the methods to search for base-editing enzymes with better
fidelity. This led them to a collection of enzymes that can convert cytosine
to thymine without several off-target mutations. This is very important in
using base editing as medicine. The team is planning to screen for base
editors that will work well in plant cells.