E, RMD induced by Cas9-D10A is dependent on POLD3. U2OS (EGFP-SSA-3427-17) cells were infected with lentiviruses expressing shRNA for POLD3 or vector control and RMD was determined after cleavage by the indicated sgRNAs/Cas9-D10A. The distance between sgRNA/Cas9-D10A cleavage sites and the left and right repeat sequences is indicated at the bottom. The knockdown level of POLD3 was shown by Western blot, and KU70 was used as the loading control. 