RNA synthesis during bacteriophage SPO1 development: six classes of SPO1 RNA.

Abstract

An analysis of RNA synthesis during development of Bacillus subtilis phage SPO1 is presented. Host transcription decreases substantially after infection. The inhibition of host transcription is non-co-ordinate, with messenger synthesis much more strongly affected than stable RNA synthesis. Viral RNA synthesis increases concurrently with this shut-down and eventually accounts for at least half of the total transcription. The program of viral transcription has been analyzed by DNA-RNA hybridization-competition. Six classes of viral transcripts can be distinguished on the basis of their times of first appearance and cessation of synthesis. Viral RNA first appears about one minute after formation of phage-bacterial complexes, e and em viral RNA start to be synthesized at that time and e RNA synthesis lasts only until about the fourth minute, while em RNA synthesis is shut-off soon after the start of viral DNA replication, m and m 1 l , RNA synthesis starts four to five minutes after infection; m transcription ceases soon after the onset of DNA replication whereas m 1 l , transcription continues throughout the rest of the viral eclipse period. m 2 l and l transcripts first appear a little before, and several minutes after, the start of replication, respectively; m 2 l and l RNA continue to be made throughout the rest of the viral eclipse period.