Dynamics of DNA synthesis disturbance and recovery after fractionated irradiation of S phase cells.

Using the autoradiographic method we studied the kinetics of DNA synthesis during themitotic cycle of mouse corneal epithelial cells after γ-irradiation in a dose of 2 Gy at different S-phase points. Normally, S phase in corneal epitheliocytes includes S1 and S2 phases separated by an interval during which DNA is not synthesized. Double exposure modifies the pattern of DNA synthesis in the cell due to reparation of injuries. The reparative processes in the cell are realized during the interval between the S1 and S2 phases and at the expense of g1 period of the mitotic cycle. If the cell has no time for reparation, the injuries are transferred into the class of "latent" injuries.