title: Organization of the LEE1 operon regulatory region of enterohaemorrhagic Escherichia coli O157:H7 and activation by GrlA.
abstract: Expression of the genes in the locus of enterocyte effacement (LEE) in enterohaemorrhagic Escherichia coli is primarily co-ordinated by expression of the LEE1 operon. GrlA is a LEE-encoded transcription regulator that has been proposed to be involved in the regulation of expression of the LEE1 operon. We describe a simple plasmid-based system to investigate the LEE1 operon regulatory region and to study GrlA-dependent effects. We report that GrlA can activate transcription initiation at the LEE1 P1 promoter by binding to a target located within the 18-base-pair spacer between the promoter -10 and -35 elements, which were defined by mutational analysis. Shortening this spacer to 17 base pairs increases P1 promoter activity and short-circuits GrlA-dependent activation. Hence, at the P1 promoter, the action of GrlA resembles that of many MerR family transcription activators at their target promoters.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Md Shahidul
authors.initials: MS
authors.lastname: Islam
authors.forename: Lewis E H
authors.initials: LE
authors.lastname: Bingle
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Pallen
authors.forename: Stephen J W
authors.initials: SJ
authors.lastname: Busby
mesh_terms: D001483:Base Sequence; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics; D019453:Escherichia coli O157 / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D008954:Models, Biological; D008969:Molecular Sequence Data; D009876:Operon; D010750:Phosphoproteins / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C513430:GrlA protein, E coli; C457340:LEE protein, E coli; D010750:Phosphoproteins; D015534:Trans-Activators