S 1 Nuclease from Aspergillus oryzae for the Detection of DNA Damage and Repair in the Gamma-Irradiated Intracerebral Rat Gliosarcoma 9L
- 1 October 1977
- journal article
- research article
- Published by JSTOR in Radiation Research
- Vol. 72 (1) , 100-106
- https://doi.org/10.2307/3574560
Abstract
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 22.degree. C. The fraction of tumor DNA remaining double-stranded after this exposure to alkali was determined by its resistance to S1 nuclease from A. 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 1st-order kinetics. DNA from tumors excised at intervals after irradiation showed a greater double-stranded fraction in alkali than that from tumors excised immediately, indicating repair of single-strand breaks. Repair of damage produced by 600 rads proceeded with a half-time of .apprx. 15 min.This publication has 6 references indexed in Scilit:
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