Transcription of bacteriophage fl. The major in vivo RNAs.

We have analyzed eight major phage-specific mRNA species which are synthesized following infection of Escherichia coli with bacteriophage fl. The approximate half-lives of these RNAs appear to be inversely proportional to their lengths. Three species have the properties of primary transcripts. They are labeled very rapidly with [3H]uracil, and they co-migrate by sodium laruyl sulfate-urea polyacrylamide gel electrophoresis with the three major RNAs transcribed from replicative form DNA in vitro using [gamma-32P]GTP as the labeled ribonucleoside triphosphate. At least three of the remaining RNAs synthesized in vivo arise by some type of processing reaction. The processed species contain, as determined by oligonucleotide analysis, the information for the gene VIII protein and the 3'-terminal oligonucleotide expected for a transcription termination event at the rho-independent site following gene VIII. The two primary transcripts which could be analyzed also have this same 3'-terminal oligonucleotide. These results suggest that the processed mRNAs are the 3'-terminal cleavage products of primary transcripts which had terminated at the rho-independent site.