title: Regulation of the divergent guaBA and xseA promoters of Escherichia coli by the cyclic AMP receptor protein.
abstract: The gua promoter (guaP) of Escherichia coli resembles those for ribosomal RNA (rrn) operons and lies in a close back-to-back arrangement with the promoter for xseA (xseP). Transcription from guaP is subject to stringent control and growth-rate-dependent regulation, and to repression by DnaA and PurR. In addition, transcription from guaP is regulated by the cyclic AMP receptor protein (CRP). Plasmid-borne promoter fusions to the receptor gene for chloramphenicol acetyl transferase were used to assess the role of CRP in controlling transcription from guaP and xseP following a downshift of cultures from rich into minimal medium. CRP is required to activate guaBA transcription and repress xseA transcription following downshift. Bandshift assays with a DNA fragment carrying the divergent promoters revealed specific binding of CRP. We propose that CRP, binding to a near-consensus site centred at -117.5, activates transcription from guaP and obstructs transcription from the xseA promoter.
authors.affiliation: Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Biomedical Sciences Building, Bassett Crescent East, SO16 7PX, Southampton, UK.
authors.forename: M I
authors.initials: MI
authors.lastname: Hutchings
authors.forename: W T
authors.initials: WT
authors.lastname: Drabble
mesh_terms: D001483:Base Sequence; D003470:Culture Media; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006150:Guanine Nucleotides / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D009876:Operon; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D003470:Culture Media; D002373:Cyclic AMP Receptor Protein; D006150:Guanine Nucleotides; D005090:Exodeoxyribonucleases; C026870:exodeoxyribonuclease VII