Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2006-2-1
pubmed:abstractText
Expression of the anaerobically inducible focA-pfl operon in Escherichia coli was activated nearly sevenfold relative to wild-type under aerobic growth conditions by increasing the dosage of the fnr gene on a pBR322-based plasmid (pCH21). No effect on anaerobic expression levels was observed, suggesting that operon expression under these conditions is maximal. Examination of the complex transcript pattern of the focA-pfl operon confirmed that in strains bearing pCH21 all transcripts, with the exception of the promoter 7 transcript, were up-regulated aerobically. Western analysis of strains bearing pCH21 revealed that the fumarate nitrate regulator (FNR) level was increased approximately ninefold relative to the level in strains bearing a single copy of the fnr gene aerobically, but was only overproduced threefold anaerobically. Analysis of an fnr-lacZ fusion indicated that fnr expression was more strongly negatively autoregulated in anaerobic cells compared with aerobic cells when pCH21 was present. Taken together, these findings suggest that high-level overproduction of FNR is prevented anaerobically by active FNR repressing expression of the fnr gene. Furthermore, transcription from promoter 7 of the focA-pfl operon, which depends on both ArcA-P and FNR, cannot be activated aerobically by overproduction of FNR alone, while promoter 6, which is less dependent on ArcA-P, can be activated under these conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0378-1097
pubmed:author
pubmed:issnType
Print
pubmed:volume
255
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
262-7
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Aerobic activation of transcription of the anaerobically inducible Escherichia coli focA-pfl operon by fumarate nitrate regulator.
pubmed:affiliation
Department of Molecular Microbiology, John Innes Centre, Norwich, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't