Replication terminator protein of Escherichia coli is a transcriptional repressor of its own synthesis.
We have investigated the regulation of synthesis of the replication terminator protein (Ter) of Escherichia coli and have discovered that the protein is a repressor of its own synthesis at the transcriptional step. Since the synthesis of Ter protein was observed to be down-regulated in vivo, these results are consistent with autoregulation as one control mechanism of Ter protein within the cell. Analysis of the tus gene that encodes the Ter protein revealed that transcription was initiated from a single promoter located within the upstream nontranscribed sequence. In vitro footprinting experiments have revealed that Ter protein prevented binding of RNA polymerase to the promoter sequence when both proteins were incubated with promoter DNA. However, once bound to the promoter, RNA polymerase could not be displaced by Ter protein. Conversely, prebound Ter protein could not be dislodged from its binding site at the promoter when challenged with RNA polymerase. Therefore, Ter protein can serve as a transcriptional repressor of its own synthesis by preventing RNA polymerase from binding to the tus promoter when both proteins are present in the cell milieu.
Natarajan
S
S
Department of Microbiology and Immunology, Duke University Medical Center, Durham, NC 27710.
Kelley
W L
WL
Bastia
D
D
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000502:physiology*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C062011:DNA replication terminus site-binding protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012333:RNA, Messenger; D012321:DNA-Directed RNA Polymerases