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B6db references: 17163976

type Journal Article
authors Chant EL, Summers DK.
title Indole signalling contributes to the stable maintenance of Escherichia coli multicopy plasmids
journal Mol Microbiol
sel selected
ui 17163976
year (2007)
volume 63
number 1
pages 35-43
abstract The efficient transmission of multicopy plasmids to daughter cells at division requires that a high copy number is maintained. Plasmid multimers depress copy number, thereby causing instability. Various mechanisms exist to counter multimerization and thus ensure stable maintenance. One well-studied example is the multimer resolution system of the Escherichia coli plasmid ColE1 which carries a recombination site (cer) at which multimers are resolved to monomers by the XerCD recombinase. A promoter within cer initiates synthesis of a short transcript (Rcd) in multimer-containing cells. The Rcd checkpoint hypothesis proposes that Rcd delays cell division until multimer resolution is complete. We have identified tryptophanase (which catabolizes tryptophan to pyruvate and indole) as an Rcd binding protein. Furthermore, the stabilization of multicopy plasmids by Rcd is shown to be tryptophanase dependent, and a tryptophanase-deficient strain is resistant to growth inhibition by Rcd overexpression. Rcd increases the affinity of tryptophanase for its substrate tryptophan which causes increased indole production by cells in low-density cultures. Thus Rcd-mediated stabilization of multicopy plasmids is dependent upon indole acting as a signalling molecule. This is an novel role for this molecule which previously has been implicated in quorum sensing-like processes at high cell density.
last changed 2008/01/22 18:18

B6db references