Abstract: Provided are a protein complex in which estrogen receptor 2 (-ERT2) is fused to CRISPR associated protein 9 (Cas9), and a recombinant vector carrying a gene coding the protein complex, wherein ERT2 is bonded to the N-terminus and C-terminus of nuclear localization sequence (NLS)-removed Cas9 and the complex has the advantage of translocating from the cytosol into the nucleus at a certain time point upon treatment with tamoxifen and modifying a specific DNA with the aid of guide RNA (gRNA), ultimately enabling a more elaborate DNA modification operation in a desired part at a desired time point.

Abstract: Provided are an improved genome editing system and a method that has high specificity, which are capable of obtaining stable mutation types. The system includes an expression construct including a coding sequence of a gRNA targeting at least one genomic target sequence; an expression construct including a coding sequence of a CRISPR nuclease; and an expression construct including a coding sequence for a gRNA targeting a target sequence within the coding sequence of the CRISPR nuclease. Upon introduction into the cell, the gRNA targeting the at least one genomic target sequence directs the CRISPR nuclease to the at least one genomic target sequence and results in one or more mutations in the genomic target sequence, and the gRNA targeting a target sequence within the coding sequence of the CRISPR nuclease directs the CRISPR nuclease to the target sequence within the coding sequence of the CRISPR nuclease and results in an inactivating mutation of the CRISPR nuclease.