Murine cytomegalovirus gene expression during nonproductive infection in go-phase 3T3 cells

Murine 3T3 cells, maintained in the Go-phase by deprivation of serum, were infected with murine cytomegalovirus (MCMV) and examined for the synthesis of viral DNA, RNA, and proteins. No viral DNA replication could be detected, although the viral genome remained viable since infectious centers persisted. Viral RNA was analyzed by reassociation kinetics with ¹²⁵I-MCMV DNA. At early and late times after infection, the percentage of viral DNA transcribed amounted to 18% and 21%, respectively (comprising one abundance class), in contrast to 26% and 38%, respectively (two abundance classes), at corresponding times during productive infection in growing 3T3 cells. Five viral polypeptides were detected in the Go-phase cells, but these did not include structural polypeptides. When infected Go-phase cells were exposed to serum and fresh medium, viral DNA synthesis occurred, and progeny virions appeared subsequently. Thus this system may prove useful for analyzing a latent herpes infection in vitro.