The relative stability of selected herpes simplex virus type 1 mRNAs

The relative stability of herpes simplex virus type 1 mRNAs was investigated by examination of the decay rates of selected viral transcripts. The synthesis of mRNA was inhibited by the addition of dactinomycin to HSV-1 infected cells, and the abundance of individual transcripts was determined at subsequent times by RNA blot hybridization. For two immediate-early mRNAs, those encoding the 110 and 63 kilodalton immediate-early proteins, RNA synthesis was inhibited at 3 h post-infection and mRNA half-lives of 5-7 h were found. Examination at 5 h post-infection of the early mRNA encoding thymidine kinase as well as the late mRNA encoding glycoprotein H revealed half-lives of 8-11 h. In contrast, at 12 h post-infection, the late mRNAs encoding the glycoproteins C, E, as well as H were found to have half-lives of 14-29 h. These findings suggest that the relative stability of viral mRNA increases late in infection and is dependent upon the time after infection rather than being strictly a property of the mRNA itself.