title: Three members of polyamine modulon under oxidative stress conditions: two transcription factors (SoxR and EmrR) and a glutathione synthetic enzyme (GshA).
abstract: Members of polyamine modulon whose synthesis is enhanced at the level of translation were looked for under oxidative stress conditions caused by 0.6 μM K2TeO3. When an Escherichia coli polyamine-requiring mutant MA261 was cultured in the presence of K2TeO3, the degree of polyamine stimulation of cell growth was greater than in cells cultured in the absence of K2TeO3. Under these conditions, synthesis of SoxR, a transcriptional factor for expression of the superoxide response regulon, EmrR, a negative transcriptional factor for expression of the genes for drug excretion proteins, EmrA and EmrB, and of GshA, γ-glutamylcysteine synthetase necessary for glutathione (GSH) synthesis, were stimulated by polyamines at the level of translation. Polyamine stimulation of SoxR and EmrR synthesis was dependent on the existence of an unusually located Shine-Dalgarno (SD) sequence in soxR and emrR mRNAs. Polyamine stimulation of GshA synthesis was due to the existence of the inefficient initiation codon UUG instead of AUG. Polyamine stimulation of the synthesis of EmrR was mainly observed at the logarithmic phase of growth, while that of the synthesis of SoxR and GshA was at the stationary phase. These results strongly suggest that polyamines are involved in easing of oxidative stress through stimulation of synthesis of SoxR, EmrR and GshA together with RpoS, previously found as a member of polyamine modulon at the stationary phase.
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sakamoto
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Terui
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Taketo
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto, Kyoto, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan.
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishihama
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Chiba, Japan; Amine Pharma Research Institute, Innovation Plaza at Chiba University, Chiba, Chiba, Japan.
authors.forename: Kazuei
authors.initials: K
authors.lastname: Igarashi
authors.affiliation: Faculty of Pharmacy, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D018387:Codon, Initiator; D004151:Dipeptides / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005978:Glutathione / Q000096:biosynthesis; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics; D011073:Polyamines / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018085:Regulon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D018387:Codon, Initiator; D004151:Dipeptides; C489681:EmrA protein, E coli; C539510:EmrB protein, E coli; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D011073:Polyamines; D012333:RNA, Messenger; D012808:Sigma Factor; D014157:Transcription Factors; C069567:sigma factor KatF protein, Bacteria; C070724:SoxR protein, Bacteria; D005978:Glutathione; C017341:gamma-glutamylcysteine