Indole signalling contributes to the stable maintenance of Escherichia coli multicopy plasmids

摘要: The efficient transmission of multicopy plasmids to daughter cells at division requires that a high copy number is maintained. Plasmid multimers depress number, thereby causing instability. Various mechanisms exist counter multimerization and thus ensure stable maintenance. One well-studied example the multimer resolution system Escherichia coli plasmid ColE1 which carries recombination site (cer) are resolved monomers by XerCD recombinase. A promoter within cer initiates synthesis short transcript (Rcd) in multimer-containing cells. Rcd checkpoint hypothesis proposes delays cell until complete. We have identified tryptophanase (which catabolizes tryptophan pyruvate indole) as an binding protein. Furthermore, stabilization shown be dependent, tryptophanase-deficient strain resistant growth inhibition overexpression. increases affinity for its substrate causes increased indole production low-density cultures. Thus Rcd-mediated dependent upon acting signalling molecule. This novel role this molecule previously has been implicated quorum sensing-like processes density.