Study of fowl plague virus RNA synthesis in temperature-sensitive mutants

Abstract

Investigation of complementary RNA (cRNA) and of virion RNA (vRNA) synthesis in vivo in five temperature-sensitive mutants of fowl plague virus (FPV) belonging to different complementation groups revealed the existence of the following phenotypes: cRNA −vRNA −, cRNA +vRNA − and cRNA +vRNA +. In one of the two mutants possessing in vivo the cRNA −vRNA − phenotype, the function of virion transcriptase in vitro was defective. Shift-up and shift-down temperature experiments showed that vRNA synthesis under nonpermissive conditions was also decreased in both these mutants. The experimental data suggest that transcription of FPV-RNA is carried out by two viral proteins and that these proteins may also take part in the process of RNA replication.