Rejoining of single breaks of DNA induced by X-rays in mammalian cells: Effects of metabolic inhibitors

  • Atsushi Tsuboi
  • Toyozo Terasima


Effects of metabolic inhibitors on the rejoining of broken single strands of DNA of mouse L cells induced by X-irradiation were studied by the sucrose gradient sedimentation method. Inhibitors of protein and DNA syntheses, such as cycloheximide and 5-fluorodeoxyuridine, could not suppress the rejoining of broken strands, when they were introduced into cultures at the time of irradiation. However, 2.5-hour pretreatment of cells with 5-fluorodeoxyuridine was capable of reducing the rate of rejoining. In addition, proflavin, one of DNA-binding substances tested, prevented the rejoining. These results suggest that pre-existing DNA-related enzymes, for instance, DNA polymerase and ligase, are responsible for the process.


Strand Break Sucrose Gradient Metabolic Inhibitor Break Single Strand Irradiate Cell 
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Copyright information

© Springer-Verlag 1970

Authors and Affiliations

  • Atsushi Tsuboi
    • 1
  • Toyozo Terasima
    • 1
  1. 1.Division of Physiology and PathologyNational Institute of Radiological SciencesChiba-siJapan

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