Identification and characterization of the terminators of the lys and P transcripts of bacteriophage Mu.
Transcription during the lytic cycle of phage Mu occurs in three phases: early, middle, and late. Late transcription requires the Mu C protein and initiates at four promoters: Plys, PI, PP, and Pmom. Northern blot analysis of total RNA isolated 30 min after heat induction of Mu cts lysogens demonstrated that the full-length lys and P transcripts were approximately 7.6 and 6.3 kb long, respectively. The 3' ends of the lys and P transcripts were further localized by S1 nuclease mapping to intergenic regions between G and I and between U and U' in both the G(+) and G(-) orientations of the invertible G segment, respectively. As expected, when DNA fragments containing these termination regions were cloned into plasmids between Pgal and the galK gene, they showed efficient termination activity, even in a Rho-deficient background. Deletion analysis indicated that efficient termination required the presence of potential RNA stem-loop structures immediately preceding the RNA 3' ends. For the P transcript from phage with the G(-) orientation, full termination activity required both the region containing the stem-loop structure and upstream sequences. Taken together, these results suggest that the transcription termination sites of the lys and P transcripts are Rho-independent terminators.
Zha
J
J
Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
Zhao
Z
Z
Howe
M M
MM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis; D010583:Bacteriophage mu / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D005686:Galactokinase / Q000032:analysis; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D013728:Terminator Regions, Genetic / Q000235:genetics*; D013997:Time Factors; D014170:Transformation, Genetic; D001618:beta-Lactamases / Q000032:analysis
D001426:Bacterial Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D005686:Galactokinase; D015719:Single-Strand Specific DNA and RNA Endonucleases; D001618:beta-Lactamases