title: The ECF sigma factor RpoI of R. leguminosarum initiates transcription of the vbsGSO and vbsADL siderophore biosynthetic genes in vitro.
abstract: When complexed with Escherichia coli RNA polymerase core enzyme, purified RpoI protein of Rhizobium leguminosarum initiated transcription in vitro from promoters of the vbsADL and vbsGSO operons, which are needed to synthesise the siderophore vicibactin. There is a single transcription initiation site for rpoI, regardless of whether the cells are grown in Fe-replete or Fe-depleted media, but levels of rpoI mRNA were reduced, though not abolished, in the presence of Fe. Unlike PvdS, a similar Pseudomonas sigma factor needed to transcribe genes involved in pyoverdine synthesis, RpoI transcribes vbsADL and vbsGSO in the absence of the cognate siderophore. The RpoI sigma factor is not required for transcription of rpoI.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Kay H
authors.initials: KH
authors.lastname: Yeoman
authors.forename: Sylvain
authors.initials: S
authors.lastname: Mitelheiser
authors.forename: Gary
authors.initials: G
authors.lastname: Sawers
authors.forename: Andrew W B
authors.initials: AW
authors.lastname: Johnston
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000502:physiology; D016961:Rhizobium leguminosarum / Q000235:genetics* / Q000378:metabolism*; D017262:Siderophores / Q000235:genetics* / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D017262:Siderophores; D012808:Sigma Factor; C401931:rpoI protein, Rhizobium leguminosarum