Diamide stress induces a metallothionein BmtA through a repressor BxmR and is modulated by Zn-inducible BmtA in the cyanobacterium Oscillatoria brevis

Kazunobu Hirose; Bunichi Ezaki; Tong Liu; Susumu Nakashima

doi:10.1016/j.toxlet.2005.11.008

Diamide stress induces a metallothionein BmtA through a repressor BxmR and is modulated by Zn-inducible BmtA in the cyanobacterium Oscillatoria brevis

Kazunobu Hirose, Bunichi Ezaki, Tong Liu, Susumu Nakashima

Research output: Contribution to journal › Article › peer-review

7 Citations (Scopus)

Abstract

A cysteine-rich metal binding protein MT (metallothionein) (named BmtA) is induced upon exposure to multiple heavy metal ions in the freshwater cyanobacterium Oscillatoria brevis. The SmtB/ArsR family repressor BxmR from O. brevis represses the expression of an operon encoding bmtA and bxmR. In the present study, the expression of bmtA was induced in vivo by diamide, a specific thiol oxidant, in O. brevis cells. In vitro electrophoretic gel mobility shift experiments revealed that the incubation with diamide induces disassembly of the BxmR-bxmR/bmtA operator (O)/promoter (P) complex [multiple resolvable complexes of BxmR with oligonucleotide (named P5) containing a single 12-2-12 inverted repeat derived from the O/P region of bxmR/bmtA]. Thus, the exposure to diamide induces MT mRNA in O. brevis, and this induction is associated with diamide-mediated inhibition of BxmR-P5 complex. BxmR is more sensitive to diamide than to H₂O_2. Furthermore, pretreatment of O. brevis with Zn decreased intracellular peroxidation products caused by diamide. Thus, these results imply that MT induced by Zn-pretreatment functions to protect O. brevis cells against diamide stress.

Original language	English
Pages (from-to)	250-256
Number of pages	7
Journal	Toxicology Letters
Volume	163
Issue number	3
DOIs	https://doi.org/10.1016/j.toxlet.2005.11.008
Publication status	Published - Jun 1 2006

Keywords

Cyanobacteria
Diamide
Metallothionein (MT)
Oscillatoria brevis
Oxidative stress
Repressor

ASJC Scopus subject areas

Toxicology

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10.1016/j.toxlet.2005.11.008

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@article{f11d408ace434ac0a89e516140663624,

title = "Diamide stress induces a metallothionein BmtA through a repressor BxmR and is modulated by Zn-inducible BmtA in the cyanobacterium Oscillatoria brevis",

abstract = "A cysteine-rich metal binding protein MT (metallothionein) (named BmtA) is induced upon exposure to multiple heavy metal ions in the freshwater cyanobacterium Oscillatoria brevis. The SmtB/ArsR family repressor BxmR from O. brevis represses the expression of an operon encoding bmtA and bxmR. In the present study, the expression of bmtA was induced in vivo by diamide, a specific thiol oxidant, in O. brevis cells. In vitro electrophoretic gel mobility shift experiments revealed that the incubation with diamide induces disassembly of the BxmR-bxmR/bmtA operator (O)/promoter (P) complex [multiple resolvable complexes of BxmR with oligonucleotide (named P5) containing a single 12-2-12 inverted repeat derived from the O/P region of bxmR/bmtA]. Thus, the exposure to diamide induces MT mRNA in O. brevis, and this induction is associated with diamide-mediated inhibition of BxmR-P5 complex. BxmR is more sensitive to diamide than to H2O2. Furthermore, pretreatment of O. brevis with Zn decreased intracellular peroxidation products caused by diamide. Thus, these results imply that MT induced by Zn-pretreatment functions to protect O. brevis cells against diamide stress.",

keywords = "Cyanobacteria, Diamide, Metallothionein (MT), Oscillatoria brevis, Oxidative stress, Repressor",

author = "Kazunobu Hirose and Bunichi Ezaki and Tong Liu and Susumu Nakashima",

note = "Funding Information: This work was partially supported by the Oohara Foundation for Agricultural Sciences, Okayama University COE (Center of Excellence) Project (to S.N.), JSPS Postdoctoral Fellowship for Foreign Researchers (to S.N.), Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (to B.E.), JSPS Joint Project under Japan–US Cooperative Science Program (to B.E.) and Japan–Korea Basic Science Cooperation Program (to B.E.). We thank Norwegian Institute for Water Research for providing O. brevis.",

year = "2006",

month = jun,

day = "1",

doi = "10.1016/j.toxlet.2005.11.008",

language = "English",

volume = "163",

pages = "250--256",

journal = "Toxicology Letters",

issn = "0378-4274",

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TY - JOUR

T1 - Diamide stress induces a metallothionein BmtA through a repressor BxmR and is modulated by Zn-inducible BmtA in the cyanobacterium Oscillatoria brevis

AU - Hirose, Kazunobu

AU - Ezaki, Bunichi

AU - Liu, Tong

AU - Nakashima, Susumu

N1 - Funding Information: This work was partially supported by the Oohara Foundation for Agricultural Sciences, Okayama University COE (Center of Excellence) Project (to S.N.), JSPS Postdoctoral Fellowship for Foreign Researchers (to S.N.), Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (to B.E.), JSPS Joint Project under Japan–US Cooperative Science Program (to B.E.) and Japan–Korea Basic Science Cooperation Program (to B.E.). We thank Norwegian Institute for Water Research for providing O. brevis.

PY - 2006/6/1

Y1 - 2006/6/1

N2 - A cysteine-rich metal binding protein MT (metallothionein) (named BmtA) is induced upon exposure to multiple heavy metal ions in the freshwater cyanobacterium Oscillatoria brevis. The SmtB/ArsR family repressor BxmR from O. brevis represses the expression of an operon encoding bmtA and bxmR. In the present study, the expression of bmtA was induced in vivo by diamide, a specific thiol oxidant, in O. brevis cells. In vitro electrophoretic gel mobility shift experiments revealed that the incubation with diamide induces disassembly of the BxmR-bxmR/bmtA operator (O)/promoter (P) complex [multiple resolvable complexes of BxmR with oligonucleotide (named P5) containing a single 12-2-12 inverted repeat derived from the O/P region of bxmR/bmtA]. Thus, the exposure to diamide induces MT mRNA in O. brevis, and this induction is associated with diamide-mediated inhibition of BxmR-P5 complex. BxmR is more sensitive to diamide than to H2O2. Furthermore, pretreatment of O. brevis with Zn decreased intracellular peroxidation products caused by diamide. Thus, these results imply that MT induced by Zn-pretreatment functions to protect O. brevis cells against diamide stress.

AB - A cysteine-rich metal binding protein MT (metallothionein) (named BmtA) is induced upon exposure to multiple heavy metal ions in the freshwater cyanobacterium Oscillatoria brevis. The SmtB/ArsR family repressor BxmR from O. brevis represses the expression of an operon encoding bmtA and bxmR. In the present study, the expression of bmtA was induced in vivo by diamide, a specific thiol oxidant, in O. brevis cells. In vitro electrophoretic gel mobility shift experiments revealed that the incubation with diamide induces disassembly of the BxmR-bxmR/bmtA operator (O)/promoter (P) complex [multiple resolvable complexes of BxmR with oligonucleotide (named P5) containing a single 12-2-12 inverted repeat derived from the O/P region of bxmR/bmtA]. Thus, the exposure to diamide induces MT mRNA in O. brevis, and this induction is associated with diamide-mediated inhibition of BxmR-P5 complex. BxmR is more sensitive to diamide than to H2O2. Furthermore, pretreatment of O. brevis with Zn decreased intracellular peroxidation products caused by diamide. Thus, these results imply that MT induced by Zn-pretreatment functions to protect O. brevis cells against diamide stress.

KW - Cyanobacteria

KW - Diamide

KW - Metallothionein (MT)

KW - Oscillatoria brevis

KW - Oxidative stress

KW - Repressor

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U2 - 10.1016/j.toxlet.2005.11.008

DO - 10.1016/j.toxlet.2005.11.008

M3 - Article

C2 - 16359831

AN - SCOPUS:33645895565

SN - 0378-4274

VL - 163

SP - 250

EP - 256

JO - Toxicology Letters

JF - Toxicology Letters

IS - 3

ER -

Diamide stress induces a metallothionein BmtA through a repressor BxmR and is modulated by Zn-inducible BmtA in the cyanobacterium Oscillatoria brevis

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