A New DNA Break Repair Pathway Involving PARP3 and Base Excision Repair Proteins.

Poly(ADP-ribosyl)ation, which is catalyzed by PARP family proteins, is one of the main reactions in the cell response to genomic DNA damage. Massive impact of DNA-damaging agents (such as oxidative stress and ionizing radiation) causes numerous breaks in DNA. In this case, the development of a fast cell response, which allows the genomic DNA integrity to be retained, may be more important than the repair by more accurate but long-term restoration of the DNA structure. This is the first study to show the possibility of eliminating DNA breaks through their PARP3-dependent mono(ADP-ribosyl)ation followed by ligation and repair of the formed ribo-AP sites by the base excision repair (BER) enzyme complex. Taken together, the results of the studies on ADP-ribosylation of DNA and the data obtained in this study suggest that PARP3 may be a component of the DNA break repair system involving the BER enzyme complex.