Kinetics of repair of DNA single-strand breaks in cultured mammalian cells. Part I. The dependence on irradiation dose and cell cycle stage

Repair of radiation-induced lesions leading to reproductive cell death strongly affects the cell radiosensitivity and its dependence on the cell cycle stage. In most reported work on the repair of DNA breaks the main questions are whether or not there exists the phenomenon of repair, and what is its biochemical mechanism. Information on the kinetics of this process is still lacking. The present work was aimed at studying the kinetics of repair of DNA single-strand breaks in asynchronous cultures of Chinese hamster cells, which are widely used in radio-biological experiments, and in cultures of these cells synchronized at the G sub(1) stage after irradiation with doses of 15 and 200 Gy, which induce reproductive and interphase death of cells, respectively.