ABSTRACT
Cytomegaloviruses (CMV) are ubiquitous, highly species-specific herpes viruses (Alford and Britt, 1985). As with other herpes viruses, primary CMV infection is often followed by persistent and/or recurrent infections. The molecular biology of the virus and the infectious cycle are well characterized. The infectious cycle is divided into immediate-early, early, and late phases, relative to the time of appearance of CMV-specific proteins and sensitivity to different pharmacological agents (Stinski et al., 1981). The immediate-early period is usually defined as up to 2-4 hours post-infection, and is characterized by the production of a number of proteins responsible for regulation of viral gene expression (Hermiston et al., 1987). These proteins are encoded by the major immediate-early transcriptional unit of the virus, and are required, along with the viral DNA polymerase, for viral replication (Heilbronn et al., 1987).
