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Hereditas(Beijing) ›› 2020, Vol. 42 ›› Issue (3): 236-249.doi: 10.16288/j.yczz.19-297

• Review • Previous Articles     Next Articles

Next-generation CRISPR-Cas for genome editing: focusing on the Cas protein and PAM

Lianchao Tang, Feng Gu()   

  1. State Key Laboratory of Ophthalmology and Optometry, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
  • Received:2019-11-12 Revised:2020-02-26 Online:2020-03-20 Published:2020-03-04
  • Contact: Gu Feng E-mail:fgu@mail.eye.ac.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China No(81201181)

Abstract:

The emergence of the gene editing technology, especial CRISPR-Cas (clustered regularly intersected short palindromic repeats and CRISPR associated proteins), has greatly promoted the ability of human beings to transform natural species. It has been widely harnessed for the engineering in the medical, industrial, agricultural and other fields. The key component of the CRISPR-Cas system, the Cas protein, possesses its specific features, including self-activity, recognition site, cutting end and guide RNA. PAM (protein assistant motif) is a number of nucleotides adjacent to the target site, which is very important for the Cas protein to recognize the target sequence and is also the key characteristic of CRISPR-Cas. There are several reported methods for identification of PAM. In this review, we summarize the searching for the Cas protein, the identification of Cas mutants with desired traits and the mapping of the PAM (including the extending of PAM spectrum), in order to provide a reference for the development and optimization of next-generation gene editing tools.

Key words: gene editing, CRISPR-Cas system, Cas protein, PAM, directed evolution