Regulation of transcription of genes required for fatty acid transport and unsaturated fatty acid biosynthesis in Escherichia coli by FadR.
Fatty acid biosynthesis and fatty acid degradation in Escherichia coli are co-ordinately regulated at the level of transcription by the product of the fadR gene, FadR. In the present work we investigate FadR interaction with the fabA and fadL promoters. The FadR-responsive operator within fabA, OA, was localized to a region -47 to -31 base pairs relative to the start of transcription using DNase I protection studies. The promoter and untranslated leader within fadL had two binding sites for FadR, OL1 at -25 to -9 and OL2 at -1 to +16 relative to the start of transcription. The binding affinity of FadR for OA and OL1 or OL2 was lower than that for the single site within fadB (OB) as measured using protein-DNA gel retention assays. Overall, these experiments demonstrated that the affinity of FadR binding for DNA containing the fadB, fadL and fabA promoters was OB > OL1, OL2 > OA. We could not distinguish separate binding affinities for OL1 or OL2. We demonstrated repression of fadL transcription and activation of fabA transcription in vitro using run-off transcription assays containing purified FadR and RNA polymerase.
DiRusso
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Department of Biochemistry, University of Tennessee, Memphis 38163.
Metzger
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Heimert
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D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D054889:Fatty Acid Synthase, Type II; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006836:Hydro-Lyases / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C057119:FadR protein, Bacteria; D050612:Fatty Acid Transport Proteins; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C065691:fadL protein, E coli; D006836:Hydro-Lyases; C047118:3-hydroxyacyl-(acyl-carrier-protein) dehydratase; D054889:Fatty Acid Synthase, Type II