Rho-dependent transcription termination in the tyrT operon of Escherichia coli.
A 178-bp repeat sequence comprises the distal end of the tyrT operon and also encodes the signal for Rho-dependent transcription termination. It is shown here that Rho-dependent transcription termination is highly efficient for each of the individually cloned first and second repeats. The presence of either repeat results in a termination efficiency of 88% (12% readthrough). When an individual DNA repeat is shortened, starting from the promoter-proximal end, so that only 56 bp remain upstream from the termination site, Rho-dependent termination activity is reduced approximately three-fold (to give 38% readthrough) and with further shortening, so that only 15 bp remain upstream, Rho-dependent termination is reduced an additional 1.8-fold (to give 59% readthrough). Finally, it is shown that the presence or absence of the tyrT terminator upstream from the lambda tR1 terminator does not affect the efficiency of transcription at termination lambda tr1.
Madden
K A
KA
Division of Biology and Medicine, Brown University, Providence, RI 02912.
Landy
A
A
D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D005809:Genes, Regulator; D009876:Operon; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D012234:Rho Factor / Q000502:physiology*; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014443:Tyrosine / Q000235:genetics*
D012329:RNA, Bacterial; D012234:Rho Factor; D014157:Transcription Factors; D014443:Tyrosine