Title
Gamma-ray induced double-strand breaks in DNA resulting from randomly-inflicted single-strand breaks: Temporal local denaturation, a new radiation phenomenon?
Author
van der Schans, G.P.
Medisch Biologisch Laboratorium TNO
Publication year
1978
Abstract
The induction of single- and double-strand breaks in DNA by γ-rays has been measured. The maximum number of nucleotide paris (a) between two independently induced single-strand breaks in opposite strands of the DNA which cannot prevent the occurrence of a double-strand break was found to amount to about 16. This value did not differ significantly for the four types of bacteriophage DNA investigated (T4, T7 and PM2 DNA, and replicative form DNA of phage phiX174) and was the same in 10-2 M phosphate buffer containing 0, 0.5 or 1 M NaCl. In 10-3 M phosphate buffer (a) was 34 nucleotide pairs. Evidence is presented that the relatively large value of (a) has to be ascribed at least partly to a temporal local denaturation accompanying the induction of a single-strand scission. A contribution of base damage that labilizes the DNA-helix, between two single-strand breaks to the high value of (a) can not be excluded. Chemicals/CAS: Cobalt Radioisotopes; DNA, Circular; DNA, Single-Stranded; DNA, Viral
Subject
Biology
Radioisotope
DNA strand breakage
Gamma radiation
Methodology
Theoretical study
Cobalt Radioisotopes
Coliphages
DNA, Circular
DNA, Single-Stranded
DNA, Viral
Gamma Rays
Nucleic Acid Denaturation
Time Factors
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TNO identifier
228356
ISSN
0955-3002
Source
International Journal of Radiation Biology, 33 (2), 105-120
Document type
article