Flanking sequences affect replication arrest at the Escherichia coli terminator TerB in vivo.
We have analyzed the effect of flanking sequences on Tus-induced replication arrest. pBR322 plasmid derivatives which carry the Escherichia coli replication terminator TerB at different locations were used. Efficiency of the replication arrest was estimated from the plasmid copy number and transformation frequency of tus+ cells. We found that flanking sequences do affect replication arrest efficiency, a weak arrest being correlated with the presence of an AT-rich region which is replicated just before TerB. Some sequences located after the replication terminator can also affect replication termination. We propose that the AT-rich regions might impair binding of the Tus protein to the TerB sequence or facilitate helicase-induced unwinding of DNA and Tus displacement from the TerB site.
Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
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Bierne
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Ehrlich
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Michel
D001426:Bacterial Proteins / Q000378:metabolism; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D008957:Models, Genetic; D010957:Plasmids / Q000235:genetics*; D011485:Protein Binding; D014170:Transformation, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C061910:tus protein, Bacteria; C489236:tus protein, E coli