The transfected B16 cell with plasmids
B16 cell was transfected with plasmids for p2A-EGFP knock-in at the Actb locus. HMEJ is the abbreviation of Homology-mediated end joining, which refer to the Cas9-HMEJ group in the manuscript. DNEJ is the abbreviation of double nicking end joining, which refer to the double nicking-based Cas9n in the manuscript.