Abstract: The present invention relates to the field of biomedicine and discloses a use of a C2C9 nuclease as an RNA-guided endonuclease, and a small sized genome editing system. The genome editing system comprises a C2C9 nuclease and/or a nucleic acid encoding the C2C9 nuclease, and a guide RNA or a nucleic acid encoding the guide RNA. The small sized genome editing system of the present invention can perform gene editing on at least one target sequence in a genome of prokaryotic bacteria and eukaryotic cells. The present invention also discloses a use of the genome editing system and an editing method. By using the genome editing system or method of the present invention, a target gene can be precisely knocked out or cut off, the cutting efficiency is high, and precise editing of the target gene is implemented.

Abstract: Provided is a genome editing system and method for gene editing at least one target sequence in a cell genome. The genome editing system comprises: (1) an expression construct comprising a Cas12f nuclease; and (2) an expression DNA sequence comprising a guide RNA corresponding to the Cas12f nuclease, and an expression construct of the targeting sequence of the target sequence. The gene editing system or method can accurately knock out a target gene from within a cell; in addition, in an in vitro cutting experiment, the target gene can be accurately cut.