Transcriptional mapping of human respiratory syncytial virus.

A transcriptional map for human respiratory syncytial virus was determined by measuring the kinetics of viral gene inactivation in response to UV irradiation. Monolayer cell cultures of respiratory syncytial virus-infected HEp-2 cells were exposed to UV light, and residual viral RNA synthesis was monitored both by gel electrophoresis and by hybridization to dot blots of cloned cDNAs of the 10 known viral genes. Target sizes for the 10 individual viral genes were calculated relative to the UV sensitivity of intracellular viral genome replication. Target size analysis indicated that the 10 viral genes were transcribed as a single transcriptional unit and that the transcription of an individual gene was dependent on the prior transcription of all the preceding genes. The order of gene transcription (with nomenclature according to encoded proteins) was determined to proceed from the promoter as follows: 14K, 11K, N, P, M, 9.5K, 36K, F, 24K, L.