An inducible mammalian amber suppressor: Propagation of a poliovirus mutant

We describe a general protocol for controlled gene amplification, which allows conditional expression of high levels of amber suppressor activity in monkey kidney cells, and we demonstrate its use in the genetic analysis of animal viruses by the generation and propagation of the first nonsense mutant of poliovirus. A human amber suppressor tRNASer gene linked to the SV40 origin of replication and a second DNA carrying a temperature-sensitive …