Transcription analysis of the prolate-headed lactococcal bacteriophage c2.
A detailed transcription map of the prolate-headed lactococcal phage c2 has been constructed. Transcription of about one-third of the genome, encoding 22 open reading frames, began within the first 2 min of infection and produced at least 12 overlapping transcripts that persisted until lysis occurred at 30 min after initiation of infection. The remaining two-thirds of the genome, encoding 17 open reading frames, was divergently transcribed, beginning between 4 and 6 min after initiation of infection, and resulted in at least 18 overlapping transcripts that persisted until lysis. Five very strong, simultaneously active, and probably unregulated early promoters and a single positively regulated late promoter were identified. The late promoter had an extended -10 sequence, had a significant basal level of activity in the uninduced state, and was induced to high activity by a phage gene product. The complex overlapping pattern of transcripts resulted from the action of the multiple early promoters, inefficient termination of transcription, and (possibly) processing of a late precursor transcript(s). Phage proteins were not required for these processes, and the host RNA polymerase was probably used for both early and late transcription.
Biological Science Section, New Zealand Dairy Research Institute, Palmerston North, New Zealand. mark.lubbers@nzdri.org.nz
M W
MW
Lubbers
K
K
Schofield
N R
NR
Waterfield
K M
KM
Polzin
D001435:Bacteriophages / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D004279:DNA, Viral; D017045:Lactococcus / Q000821:virology*; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012323:RNA Processing, Post-Transcriptional; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D015854:Up-Regulation
D017931:DNA Primers; D004279:DNA, Viral