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.
