The control siRNA (5’-UAAUGUAUUGGAACGCAUA-3’), BLM siRNA (5’-CCGAAUCUCAAUGUACAUAGA-3’)65 (link), RECQ5 siRNA (5’-CAGGAGGCUGAUAAAGGGUUA-3’)65 (link), TREX1 siRNA (5’-CCAAGACCAUCUGCUGUCA-3’)66 (link), CTIP siRNA (5’-GCUAAAACAGGAACGAAUC-3’)67 (link), GEN1 siRNA (5’-GUAAAGACCUGCAAUGUUA-3’) were purchased from Eurofins. The MUS81 siRNA (5’-CAGCCCUGGUGGAUCGAUA-3’ and 5’-CAUUAAGUGUGGGCGUCUA-3’)68 (link), SLX1 siRNA (5’-UGGACAGACCUGCUGGAGAUU-3’)69 (link), ERCC1 siRNA (SMARTpool ON-TARGET plus L-006311), MRE11 siRNA (SMARTpool ON-TARGET plus L-009271), EXO1 siRNA (SMARTpool ON-TARGET plus L-013120), DNA2 siRNA (SMARTpool ON-TARGET L-026431), RECQ1 siRNA (SMARTpool ON-TARGET plus L-013597), RECQ4 siRNA (SMARTpool ON-TARGET plus L-010559), WRN siRNA (SMARTpool ON-TARGET plus L-010378), BRCA2 siRNA (SMARTpool ON-TARGET plus L-003462) and RAD51 siRNA (SMARTpool ON-TARGET plus L-003530) were purchased from Dharmacon. Cells were seeded one day before siRNA treatment and transfected with 25 nM of siRNA using Lipofectamine RNAiMAX (Life Technologies).