Church: We have not found Cpf1 to be an "improved nuclease" (yet).
Most importantly, however, Cpf1 generates staggered cuts (as opposed to blunt ends by Cas9), which make it an attractive endonuclease for achieving true gene edits in nondividing cells in which the cell-autonomous homology-directed repair mechanism is not working effectively.
Two promising candidates were the Cpf1 enzymes from bacterial species Acidaminococcus and Lachnospiraceae, which Zhang and his colleagues then showed can target genomic loci in human cells.
The newly described Cpf1 system differs in several important ways from the previously described Cas9, with significant implications for research and therapeutics, as well as for business and intellectual property:
The Cpf1 system is simpler in that it requires only a single RNA.
Second, and perhaps most significantly: Cpf1 cuts DNA in a different manner than Cas9.
Third: Cpf1 cuts far away from the recognition site, meaning that even if the targeted gene becomes mutated at the cut site, it can likely still be re-cut, allowing multiple opportunities for correct editing to occur.
Fourth: the Cpf1 system provides new flexibility in choosing target sites.
"The unexpected properties of Cpf1 and more precise editing open the door to all sorts of applications, including in cancer research," said Levi Garraway, an institute member of the Broad Institute, and the inaugural director of the Joint Center for Cancer Precision Medicine at the Dana-Farber Cancer Institute, Brigham and Women's Hospital, and the Broad Institute.