FNR activates and represses transcription in vitro.
FNR is an iron-binding transcriptional regulator for anaerobic gene expression in Escherichia coli. Footprinting studies with the purified protein have confirmed that it is a site-specific DNA-binding protein. Transcription tests with the positively-regulated FFmelR promoter and the negatively-regulated ndh promoter likewise demonstrated that FNR can activate or repress transcription in vitro. Reducing conditions were not required but activity was abolished by substituting an essential cysteine residue with alanine (C122A) and the affinity for DNA was reduced by iron-depletion. The start point(s) for transcription of the FNR-repressed NADH dehydrogenase II gene (ndh) were identified by transcript mapping and the corresponding promoter (-35 and -10 sequences) was located immediately downstream of the FNR-binding site.
Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K.
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Sharrocks
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Guest
D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D003850:Deoxyribonuclease I; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial; D007506:Iron-Sulfur Proteins; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000235:genetics; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C060704:FNR protein, E coli; D007506:Iron-Sulfur Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D009245:NADH Dehydrogenase; D003850:Deoxyribonuclease I