Cpf1 Is a Single RNA Guided Endonuclease of a Class 2 CRISPR Cas System
The microbial adaptive immune system CRISPR mediates defense against foreign genetic elements through two classes of RNA guided nuclease effectors. Class 1 effectors utilize multi protein complexes, whereas class 2 effectors rely on single component effector proteins such as the well characterized Cas9. Here, we report characterization of Cpf1, a putative class 2 CRISPR effector. We demonstrate that Cpf1 mediates robust DNA interference with features distinct from Cas9. Cpf1 is a single RNA guided endonuclease lacking tracrRNA, and it utilizes a T rich protospacer adjacent motif. Moreover, Cpf1 cleaves DNA via a staggered DNA double stranded break. Out of 16 Cpf1 family proteins, we identified two candidate enzymes from Acidaminococcus and Lachnospiraceae, with efficient genome editing activity in human cells. Identifying this mechanism of interference broadens our understanding of CRISPR Cas systems and advances their genome editing applications.
Cell