C, Long-range RMD is dependent on POLD3 when one DSB is close to a repeat. mES cells carrying the RMD-GFP reporter were transfected with nontargeting siRNA (Ctrl) or a pool of POLD3 siRNAs (siPOLD3) 24 hours before for the first time, and with transfection of sgRNAs/Cas9 the second time. The graphs show the frequency of GFP+ cells normalized to the transfection efficiency. The distance between the sgRNA targeting sites and the repeats is indicated. 