title: 3-Aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase, is a stimulator, not an inhibitor, of DNA repair.
abstract: An inhibitor of poly(ADP-ribose) synthesis, 3-aminobenzamide (3AB), at low concentrations (0.01-0.1 mM) was found to reduce strand-break frequencies and increase repair replication in human lymphoid cells damaged by methyl methanesulfonate. A concentration of 0.1 mM 3AB was adequate to produce a maximum effect on strand-break frequencies and repair replication. This evidence, together with our previous measurements, demonstrates that 3AB cannot be regarded as an inhibitor of DNA repair; rather, it actually accelerates the ligation of DNA repair patches. Previous considerations of 3AB as a repair inhibitor may have derived from the use of excessive concentrations above 1 mM that may have stimulated additional damage and from the use of ethyl alcohol as a solvent for 3AB. Interpretations of the role of single-strand breaks and poly(ADP-ribose) in DNA repair, differentiation, and gene activity may need reevaluation because they have frequently been based on an erroneous notion of 3AB as a repair inhibitor, when its mode of action is, in fact, more complex.
mesh_terms: D001549:Benzamides / Q000494:pharmacology*; D002460:Cell Line; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects*; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D013268:Stimulation, Chemical
chemical_list: D001549:Benzamides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; C025160:3-aminobenzamide; D004247:DNA; D008741:Methyl Methanesulfonate