The regulations of gamma (structural) polypeptide synthesis in herpes simplex virus types 1 and 2 infected cells

The polypeptides specified by herpes simplex viruses types 1 and 2 form at least three groups designated as alpha, beta and gamma. The structural polypeptides are largely contained in the gamma polypeptide group. In this study, we investigated the transition from beta to gamma polypeptide synthesis. Our data show the following: (i) gamma polypeptide synthesis in the presence of inhibitors of DNA synthesis in the presence of inhibitors of DNA synthesis is multiplicity-dependent. Some gamma polypeptides are not detectable in cells infected with 1 PFU per cell form a significant fraction of viral polypeptides in cells infected with 25--500 PFU per cell. (ii) The mRNAs specifying these polypeptides have a relatively short half-life as measured by the relative rate of decay of gamma polypeptide synthesis in infected cells following exposure to actinomycin D. Our data thus suggest that: (i) the transition from beta to gamma polypeptide synthesis does not require the synthesis of viral DNA; and (ii) the rate of synthesis of viral structural (gamma) polypeptides is linked to the size of the viral DNA pool as a consequence of a relatively short-lived mRNA.