BIH scientists optimise CRISPR gene scissors

In Science Advances the team of Dr. Dominik Niopek at the University Hospital in Heidelberg and BioQuant Centre and Roland Eils at BIH Berlin present a way to improve the precision of the CRISPR-Cas9 system by coupling Cas9 to artificial inhibitory domains.  "We can simulate the individual steps of genome editing in a computer model," said Eils, adding, "the more active the genetic scissors are, the more likely they are to make mistakes."
 
The researchers seeked procedures of reducing the activity of the gene editing system to such an extent that they still efficiently cut the desired target sequence in the genome, but avoid to cleave similar sequences. They created hybrids from the CRISPR gene scissors and so-called anti-CRISPR (AcR) proteins, which reduce the activity of the gene scissors either by being coexpressed with or directly fused to Cas9 to fine-tune its activity, thereby achieving an effective kinetic insulation of ON- and OFF-target editing events. The researchers then compared the artificially attenuated genetic scissors with the original variant in cell cultures.

"In many cases, the attenuated genetic scissors actually work more accurately. The increase in precision depended on the sequence of the genetic material that is targeted," according to co-author Sabine Aschenbrenner.