Loss of supercoiled viral DNA after infection of permissive cells by simian virus 40.

During infection of BS-C-1 cells (a permissive line of monkey kidney cells) with simian virus 40, there was a loss of infecting viral supercoiled (component I) DNA molecules which was partially inhibited by cycloheximide. The kinetics of loss of component I in the presence of cycloheximide suggested that the loss was the result of at least two activities acting on the DNA, one cycloheximide sensitive and the second cycloheximide insensitive. Nucleotides from degraded infecting viral DNA were reincorporated into cell DNA that was synthesized during the infection.