PARP-1 activity is rescued by re-expression of NEDP1 in NEDP1 KO cells. Western blot analysis of whole cell lysates from WT and NEDP1 KO U2OS cells transfected with the indicated constructs. 72 hours after transfection, cells were treated with the indicated amount of H2O2 and processed for Western blot analysis. PAR polymer generation is reduced in NEDP1 KO cells but can be rescued by the transient re-expression of NEDP1. 