PMID: 9537361Apr 16, 1998Paper

Characterization of the cvaA and cvi promoters of the colicin V export system: iron-dependent transcription of cvaA is modulated by downstream sequences

Journal of Bacteriology
A E Boyer, P C Tai

Abstract

Secretion of the Escherichia coli toxin colicin V was previously determined to be iron regulated via the Fur (ferric uptake regulator) protein, based on studies in fur mutants. The iron dependence of transcription and expression of cvaA, which encodes a transporter accessory protein, and cvi, encoding the colicin V immunity protein, was assessed under conditions of iron excess or depletion. Immunoblots showed that production of both Cvi and CvaA is iron dependent. The iron-dependent transcriptional start for cvaA identified by primer extension and S1 nuclease analysis, P1, lies 320 bp upstream of the translational start and is associated with a newly identified Fur binding site. Beta-galactosidase activity in transcriptional lacZ fusions with the P1 promoter alone is higher than with downstream sequences present and is induced 10-fold by iron depletion. Including immediate downstream regions with P1 enhances activity from P1 even more but reduces the induction by iron depletion fivefold. Including subsequent downstream sequences, however, down-modulates overall transcription from P1 almost fourfold. Deletion of a long stem-loop structure in this region alleviates the down-modulation by increasing transcription, indicating that ...Continue Reading

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Citations

Jan 27, 2004·Antimicrobial Agents and Chemotherapy·Anne-Marie PonsGilles Cottenceau
Oct 28, 2019·Frontiers in Microbiology·Fernando BaqueroDaniel A Bravo-Vázquez
Dec 30, 2010·Antimicrobial Agents and Chemotherapy·Natacha MorinSophie Sablé
Jul 27, 2007·Natural Product Reports·Sophie DuquesneSylvie Rebuffat
Nov 9, 2002·Biochimie·Volkmar BraunKlaus Hantke
Jan 16, 2003·Biochimica Et Biophysica Acta·Douglas M Templeton, Ying Liu

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