D, RMD is stimulated when Cas9-D10A is used to create a nick near the repeat. The repair frequencies of the U2OS (MMEJ) reporter cell line (left) and U2OS (EGFP-SSA-3427-17) cell line (right) were determined after expression of the indicated sgRNAs/Cas9 and sgRNAs/Cas9-D10A. The distance between the sgRNA cleavage sites and the left and right repeat sequences is indicated (right bottom). 