Effect of heat shock on poly(ADP-ribose) synthetase and DNA repair in Drosophila cells

Journal Article · Thu Apr 01 04:00:00 EST 1982 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575806· OSTI ID:5500167

Nolan, N L; Kidwell, W R

Poly(ADP-ribose) synthetase, a chromatin-bound enzyme which attaches polyanionic chains of ADP-ribose to nuclear proteins, was found to be temperature sensitive in intact Drosophila melanogaster cells. The synthetase was completely inactivated by heat-shocking the cells at 37/sup 0/C for 5 min, a condition which had no appreciable effect on the subsequent growth of Drosophila cells at their physiological temperature. The heat-shock effect on synthetase was reversible; enzyme activity began to reappear about 2 hr post heat shock. During the 2-hr interval when poly(ADP-ribose) synthetase was absent, the cells were competent in repair of ..gamma..-ray-induced DNA strand breaks as shown by DNA sedimentation studies on alkaline sucrose gradients. It is thus concluded that poly(ADP-ribose) synthesis is unnecessary for repair of DNA strand breaks introduced by irradiation. The same conclusion was reached from the fact that two inhibitors of poly(ADP-ribose) synthetase 3-aminobenzamide and 5-methylnicotinamide, failed to block repair of ..gamma..-ray-induced DNA chain breaks even though both inhibitors reduced the amount of poly(ADP-ribose) synthesized in cells by 50-75%. Although it was found that the repair of DNA strand breaks is independent of poly(ADP-ribose) synthesis, irradiation does activate the synthetase in control cells, as shown by radioimmunoassay of poly(ADP-ribose) levels.

• Research Organization: National Cancer Inst., Bethesda, MD
• OSTI ID: 5500167
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 90:1; ISSN RAREA
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
ARTHROPODS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BIOLOGICAL SHOCK
DIPTERA
DNA
DROSOPHILA
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
FLIES
FRUIT FLIES
GAMMA RADIATION
INSECTS
INVERTEBRATES
IONIZING RADIATIONS
ISOTOPE APPLICATIONS
LIGASES
MEDIUM TEMPERATURE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
RADIATIONS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOINDUCTION
RADIOSENSITIVITY
RECOVERY
REPAIR
STRAND BREAKS
TRACER TECHNIQUES