In vivo transcription of bacteriophage phi 29 DNA: transcription termination.

The main early and late transcription termination sites in vivo in bacteriophage phi 29 DNA were determined by nuclease S1 mapping. Transcription of the phi 29 early genes located at the left end of the viral genome terminated at the very end of the DNA molecule and within the HindIII G fragment of the viral DNA. Transcription termination of the early genes located at the right end of the genome and that of the late viral genes overlapped in a specific region of the phi 29 DNA within the EcoRI D fragment. Stem-loop structures followed by uridine-rich tails could be derived close to the 3' ends of early and late mRNAs, suggesting Rho-independent transcription termination in phi 29 DNA.