Yongsub Kim1, Seung-A Cheong2, Jong Geol Lee2,3, Sang-Wook Lee4, Myeong Sup Lee1, In-Jeoung Baek2,5 & Young Hoon Sung2,5
1Department of Biomedical Sciences, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. 2Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea. 3College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea. 4Department of Radiation Oncology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. 5Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Correspondence to : Sang-Wook Lee or Myeong Sup Lee or In-Jeoung Baek or Young Hoon Sung
To the Editor:
Engineered nucleases, including transcription activator-like effector nucleases (TALENs) and CRISPR-Cas9, are under active development as versatile genome-editing tools in various organisms including mice1, 2, 3. Recently, diverse Cpf1 orthologs were identified as representatives of a class 2 CRISPR-Cas system in vitro and showed target-specific endonuclease activities in human cells comparable to that of Streptococcus pyogenes Cas9 (SpCas9)4. In contrast to Cas9, Cpf1 is guided by a single CRISPR RNA (crRNA) without an additional trans-activating crRNA, requires a short thymidine-rich protospacer-adjacent motif (PAM) preceding the target sequence, and introduces a staggered double-stranded break4. These simple characteristics of Cpf1 should be of great use for the generation of knockout mice.