BIR/SSA are both dependent on ATM. BIR/RMD in mES cells carrying the RMD-GFP reporter were determined after the addition of ATM inhibitor (20mM ku55933) or DMSO to the cell culture medium 24 hours before transfection of the indicated sgRNA/Cas9 or in ATM KO mES cells carrying the RMD-GFP reporter (right). 