Transcription in bacteriophage f1-infected Escherichia coli. Messenger populations in the infected cell.

Transcription of bacteriophage f1 DNA in vivo occurs in two independent regions. They are separated from one another by a strong terminator just downstream from gene VIII on one side, and by the filamentous phage intergenic space on the other. One of these regions contains genes II, V, VII, IX and VIII, and is actively transcribed. In this region there are a number of promoters but only one effective terminator. Thus, most of the RNAs that come from this region overlap and share sequences close to the termination site. The other region, which contains genes III, VI, I and IV, is transcribed much less actively. This region gives rise to a long (approximately 4 X 10(3) bases) RNA that covers the entire region, and several RNAs that overlap in the region closest to their 5' termini. Several other RNAs appear to overlap only with the 4 X 10(3) base transcript. Thus, not only the frequency but the organization of transcription differs in the two portions of the genome.