PARP1 inhibition suppresses SSA- as well as NHEJ-mediated translocations. (A) The p5pF translocation reporter system has puro and alu repeats (hatched and black boxes) flanking I-SceI sites on chromosomes 14 and 17. A translocation mediated by NHEJ reconstitutes a functional neo gene on der[17], whereas SSA reconstitutes both neo on der[17] and a functional puro gene on der[14]. SSA-mediated translocation events confer neo and puro resistance, whereas NHEJ translocations confer only neo resistance. (B) Frequencies of SSA- and NHEJ-mediated translocations are averages (± SEM) for 3 determinations. *P < .05; **P < .01. All results were normalized for survival in inhibitors.