Role of (ADP-ribose)n catabolism in DNA repair.

Poly(ADP-ribose) is a reversible covalent-modifier of chromosomal proteins in eukaryotic cells. The function of poly(ADP-ribose) is not clear, although it has been suggested to be involved in the regulation of DNA transactions such as replication, repair, and transcription. Here we describe a specific competitive inhibitor of poly(ADP-ribose) glycohydrolase, a macrocircular ellagitannin oenothein B, and a nuclear system prepared from synchronized HeLa S3 cells at mid-G1 phase that enable us to examine the role of poly(ADP-ribose) catabolism in DNA repair. The results suggest that poly(ADP-ribose) is capable of generating ATP by the concerted action of poly(ADP-ribose) glycohydrolase and ADP-ribose pyrophosphorylase and that this ATP enables repair DNA synthesis.