Programmable DNA scissors for genome editing

Could lead to new tools for creating advanced biofuels and therapeutic drugs
June 30, 2012

Programmable DNA scissors: A double-RNA structure in the bacterial immune system has been discovered that directs the Cas9 protein to cleave and destroy invading DNA at specific nucleotide sequences. This same dual RNA structure should be programmable for genome editing (credit: H. Steinberg,

A new and possibly more effective way to edit genomes has discovered by an international team of scientists at Lawrence Berkeley National Laboratory (Berkeley Lab). The discovery holds potentially big implications for advanced biofuels and therapeutic drugs, because genetically modified microorganisms, such as bacteria and fungi, are expected to play a key role in the green chemistry production of these and other valuable chemical products.

The team identified a double-RNA structure responsible for directing a bacterial protein to cleave (cut) foreign DNA at specific nucleotide sequences. The research team also found that it is possible to program the protein with a single RNA to enable cleavage of essentially any DNA sequence.

“We’ve discovered the mechanism behind the RNA-guided cleavage of double-stranded DNA that is central to the bacterial acquired immunity system,” said Jennifer Doudna, a biochemist with Berkeley Lab’s Physical Biosciences Division and professor at the University of California (UC) Berkeley, who helped lead the team. “Our results could provide genetic engineers with a new and promising alternative to artificial enzymes for gene targeting and genome editing in bacteria and other cell types.”

Doudna and her colleagues are now in the process of gathering more details on how the RNA-guided cleavage reaction works and testing whether the system will work in eukaryotic organisms including fungi, worms, plants and human cells.

This work was funded primarily by the Howard Hughes Medical Institute, the Austrian Science Fund, and the Swedish Research Council.