title: Novel regulation targets of the metal-response BasS-BasR two-component system of Escherichia coli.
abstract: The BasS-BasR two-component system is known as an iron- and zinc-sensing transcription regulator in Escherichia coli, but so far only a few genes have been identified to be under the direct control of phosphorylated BasR. Using Genomic SELEX (systematic evolution of ligands by exponential enrichment) screening, we have identified a total of at least 38 binding sites of phosphorylated BasR on the E. coli genome, and based on the BasR-binding sites, have predicted more than 20 novel targets of regulation. By DNase I footprint analysis for high-affinity BasR-binding sites, a direct repeat of a TTAAnnTT sequence was identified as the BasR box. Transcription regulation in vivo of the target genes was confirmed after Northern blot analysis of target gene mRNAs from both wild-type E. coli and an otherwise isogenic basR deletion mutant. The BasR regulon can be classified into three groups of genes: group 1 includes the genes for the formation and modification of membrane structure; group 2 includes genes for modulation of membrane functions; and group 3 includes genes for stress-response cell functions, including csgD, the master regulator of biofilm formation.
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ogasawara
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Shinohara
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan.
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishihama
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008670:Metals / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D014158:Transcription, Genetic
chemical_list: D029968:Escherichia coli Proteins; D008670:Metals