
Full text loading...
The different stages of frog virus 3 (FV 3) morphogenesis have been investigated in chick embryo fibroblasts infected at an optimal temperature for virus growth (29 °C). The metabolic requirements for morphogenesis were determined by adding inhibitors of macromolecular synthesis at different periods in the virus growth cycle. The effect of a non-permissive temperature for FV 3 replication (37 °C) was also studied in shift up experiments. The following results were obtained: (1) when DNA replication was inhibited, neither immature nor mature virus particles appeared; (2) continuous protein synthesis was required for every stage of virus morphogenesis. However, the assembly of virions into paracrystalline arrays seemed to be a passive phenomenon. (3) Continuous mRNA transcription was not necessary for assembly of capsid constituents, although most of these capsids appeared empty; there was also a striking increase in the number of aberrant virus structures. (4) If infected cells were shifted to a non-permissive temperature, virus maturation was completely inhibited.