S 1 Nuclease from Aspergillus oryzae for the Detection of DNA Damage and Repair in the Gamma-Irradiated Intracerebral Rat Gliosarcoma 9L
1977; Radiation Research Society; Volume: 72; Issue: 1 Linguagem: Inglês
10.2307/3574560
ISSN1938-5404
AutoresPhilip H. Gutin, John Hilton, Valerie J. Fein, Anne Elizabeth Allen, Michael Walker,
Tópico(s)DNA and Nucleic Acid Chemistry
ResumoGUTIN, P. H., HILTON, J., FEIN, V. J., ALLEN, A. E., AND WALKER, M. D. S1 Nuclease from Aspergillus oryzae for the Detection of DNA Damage and Repair in the GammaIrradiated Intracerebral Rat Gliosarcoma 9L. Radiat. Res. 72, 100-106 (1977). DNA damage and repair in a rat brain tumor following irradiation in vivo were measured by analysis of the rate of strand separation of the tumor DNA in alkali. Tumors were removed after irradiation and mechanically dissociated to a cellular suspension. Tumor cells were injected into alkali (pH 12) for 20 min at 220C. The fraction of tumor DNA remaining double-stranded after this exposure to alkali was determined by its resistance to S nuclease from Aspergillus oryzae. Double-stranded DNA remains (after enzyme exposure) acid-precipitable for fluorescent assay. The double-stranded fraction after exposure to alkali decreases with increasing radiation dose following first-order kinetics. DNA from tumors excised at intervals after irradiation showed a greater doublestranded fraction in alkali than that from tumors excised immediately, indicating repair of single-strand breaks. Repair of damage produced by 600 rad proceeded with a half-time of approximately 15 min.
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