Downregulation of the Escherichia coli guaB promoter by FIS.
The Escherichia coli guaB promoter (P(guaB)) regulates transcription of two genes, guaB and guaA, that are required for the synthesis of guanosine 5'-monophosphate (GMP), a precursor for the synthesis of guanine nucleoside triphosphates. Transcription from P(guaB) increases as a function of increasing cellular growth rate, and this is referred to as growth rate-dependent control (GRDC). Here we investigated the role of the factor for inversion stimulation (FIS) in the regulation of this promoter. The results showed that there are three binding sites for FIS centred near positions -11, +8 and +29 relative to the guaB transcription start site. Binding of FIS to these sites results in repression of P(guaB) in vitro but not in vivo. Deletion of the fis gene results in increased P(guaB) activity in vivo, but GRDC of P(guaB) is maintained.
F Floor, School of Medicine and Biomedical Sciences, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK.
Seyyed I
SI
Husnain
F Floor, School of Medicine and Biomedical Sciences, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK.
Mark S
MS
Thomas
D001665:Binding Sites / Q000235:genetics; D018983:DNA Footprinting; D003850:Deoxyribonuclease I / Q000378:metabolism; D015536:Down-Regulation; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D035021:Factor For Inversion Stimulation Protein / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D007168:IMP Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D020161:Physical Chromosome Mapping; D011401:Promoter Regions, Genetic / Q000235:genetics*
D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; C501034:Fis protein, E coli; D007168:IMP Dehydrogenase; D003850:Deoxyribonuclease I