Effect of a poly(ADP-ribose) polymerase inhibitor on DNA breakage and cytotoxicity induced by hydrogen peroxide and γ-radiation
✍ Scribed by Luísa Cristóvão; José Rueff
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 695 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0270-3211
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✦ Synopsis
The activity of poly(ADP-ribose) polymerase (PARP) is activated upon recognition of DNA strand breaks by its DNA-binding domain and the stimulation of this nuclear enzyme seems to be an early response of cells exposed to a variety of different DNA-damaging agents. In the present work we evaluate the effect of hydrogen peroxide and gamma-radiation on DNA strand breaks in human leukocytes in the presence and in the absence of 3-aminobenzamide (3AB), a potent inhibitor of PARP. Our results have shown differences in the role poly(ADP-ribosyl)ation in the rejoining of DNA strand breaks induced by hydrogen peroxide and gamma-radiation. We observed a PARP-dependent recovery of DNA strand breaks at the incubation time of 20-30 min in leukocytes treated with hydrogen peroxide. The repair of DNA strand breaks induced by gamma-radiation seems to be dependent on oxygen radical scavenging and the stimulation of PARP could be related to the protection of DNA strand breaks from hydroxyl radicals.