Demonstration of circularization of herpes simplex virus DNA following infection using pulsed field gel electrophoresis.

Studies of the configuration of intracellular herpes simplex virus DNA have been limited by the inability of restriction enzyme analyses to distinguish circular DNA from other configurations. To address this issue, we used pulsed-field gel electrophoresis of virus-infected, cycloheximide-treated cells and detected accumulation of viral DNA that failed to migrate out of the sample wells of the gels. This DNA lacked terminal restriction fragments and could be converted to unit-length linear species by gamma-irradiation, demonstrating the circularization of viral DNA following infection.