Evidence that herpes simplex virus DNA derived from quiescently infected cells in vitro, and latently infected cells in vivo, is physically damaged

Using polymerase chain reaction (PCR) and alkaline gel electrophoresis, the authors show that, compared with DNA derived from virions used to establish infection, herpes simplex virus DNA derived from quiescently infected rat pheochromocytoma(PC12) cells in culture accumulates alkaline-labile lesions. That is, compared with equivalent amounts of virion DNA, viral DNA from nerve growth factor–differentiated long-term infected cells in culture is consistently 3 to 10 times more refractoryto amplification by PCR. Despite using equal mole amounts of DNA isolated from quiescently infected cells( determinedby quantitative Southern blots), DNA from quiescently infected cells could not be detected by PCR under conditions in which the virion-derived DNA was easily detected. Refractorinessto PCR was confirmed by analysis with a ligation-mediated PCR technique. The refractorinesswas not the result of genomic circularization. The refractorinesswas, however, related to the time that the quiescently infected cell...