Structure and gene expression of the<i>E. coli</i>Mn-superoxide dismutase gene

Takeda, Yoshinori; Avila, Herbert A.

doi:10.1093/nar/14.11.4577

Cited by 117 publications

(57 citation statements)

References 40 publications

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“…Thus, the in vivo boundaries for SoxS-mediated transcriptional activation reported here agree very well with the MalE-SoxS binding sites identi- Gardner and Fridovich (15), which is indicated by the inverted horizontal arrows below the sequence of sodA-2. The locations of the Ϫ35 hexamers of the zwf (27), gnd (24), sodA (38), and nfo (30) promoters were previously determined by transcript mapping and are indicated by the double underlines below the sequences. Brackets above the sequences mark the primary sites for the fusions that were protected by MalESoxS from DNase I attack (11).…”

Section: Discussionmentioning

confidence: 99%

“…Plasmid pMLB1034, a derivative of pBR322, has an EcoRI-SmaIBamHI cloning site that can be used for construction of protein fusions to lacZ (34). Plasmids pDR17 (zwf), pCMP78(ϩ) (gnd), and pSOD-1 (sodA) have been described elsewhere (5,27,38). Plasmid pIT3 (nfo) carries the BamHI-EcoRI fragment from pRPC124 (30) in pRS551 (36).…”

Section: Methodsmentioning

confidence: 99%

“…The DNA sequences of the genes in this report are available in the following references: zwf (27), gnd (24), sodA (38), and nfo (30). The GenBank accession numbers for these sequences are M55005 (zwf), K02072 (gnd), M94879 (sodA), and M22591 (nfo).…”

Section: Methodsmentioning

confidence: 99%

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Genetic definition of the Escherichia coli zwf "soxbox," the DNA binding site for SoxS-mediated induction of glucose 6-phosphate dehydrogenase in response to superoxide

1995

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In Escherichia coli K-12, transcription of zwf, the gene for glucose 6-phosphate dehydrogenase, is subject to growth rate-dependent regulation and is activated by SoxS in response to superoxide stress. To define genetically the site of SoxS activation, we undertook a detailed deletion analysis of the zwf promoter region. Using specifically targeted 5 and 3 deletions of zwf sequences, we localized the SoxS activation site to a 21-bp region upstream of the zwf promoter. This minimal ''soxbox'' was able to confer paraquat inducibility when placed upstream of a normally unresponsive gnd-lacZ protein fusion. In addition, we used these findings as the basis for resecting unnecessary sequences from the region upstream of the promoters of two other SoxSregulated genes, sodA and nfo. Like the zwf soxbox, the regions required for SoxS activation of sodA and nfo appear to lie just upstream of or overlap the ؊35 hexamers of the corresponding promoters. Importantly, the sequence boundaries established here by deletion analysis agree with the primary SoxS recognition sites of zwf, sodA, and nfo that we previously identified in vitro by gel mobility shift and DNase I protection assays with a purified MalE-SoxS fusion protein.In Escherichia coli, the oxidative branch of the pentose phosphate pathway provides ribose for nucleoside biosynthesis and NADPH for reductive biosynthesis (9, 12). Two of the enzymes of this pathway, glucose 6-phosphate dehydrogenase (encoded by zwf) and 6-phosphogluconate dehydrogenase (encoded by gnd) are subject to growth rate-dependent regulation (40). The specific activities of these enzymes increase in proportion to increased growth rate during steady-state growth on different carbon sources. Studies on the growth rate-dependent regulation of zwf and gnd have shown that at least part of the increase in the specific activities of these enzymes is attributable to an increase in the transcription rates of the respective genes (25,26).Apart from its basic growth rate-dependent regulation, zwf is also a member of at least two other regulons. Thus, unlike gnd, zwf expression is transcriptionally activated by SoxS during episodes of oxidative stress induced by exposure of E. coli to superoxide-generating agents such as paraquat (17,18,39). Indeed, E. coli strains deleted for zwf are hypersensitive to oxidative stress, thus making zwf a pivotal member of the soxRS regulon (18, 21). In addition, treatment of cells with several antibiotics and aromatic weak acids appears to activate zwf transcription through the action of marA, thus making zwf a member of the multiple antibiotic resistance (mar) regulon (2,6,7,14,16).The work presented here has several overlapping long-range objectives. One is to understand the physiological basis for zwf's membership in the soxRS and marRAB regulons. The other is to identify the cis-acting regulatory sites of zwf that are involved in superoxide control for subsequent comparison with the sites required for growth rate control and for induction by antibiotics and aromatic weak...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Genetic definition of the Escherichia coli zwf "soxbox," the DNA binding site for SoxS-mediated induction of glucose 6-phosphate dehydrogenase in response to superoxide

1995

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“…Mn can also substitute for magnesium in many enzymatic reactions catalyzed by kinases (Takeda and Avila, 1986;Baly et al, 1985;Brock and Walker, 1980). Although an essential element, exposure to high levels of Mn in occupational or environmental settings and therapeutic or disease conditions (hepatic *Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Mitochondrial-dependent manganese neurotoxicity in rat primary astrocyte cultures

Yin

Aschner

Santos³

et al. 2008

Brain Research

116

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Chronic exposure to excessive levels of Mn results in a movement disorder termed manganism, which resembles Parkinson's disease (PD). The pathogenic mechanisms underlying this disorder are not fully understood. Several lines of evidence implicate astrocytes as an early target of Mn neurotoxicity. In the present study, we investigated the effects of Mn on mitochondrial function. Primary astrocyte cultures were prepared from cerebral cortices of one-day-old Sprague-Dawley rats. We have examined the cellular toxicity of Mn and its effects on the phosphorylation of extracellular signalregulated kinase (ERK) and activation of the precursor protein of caspase-3. The potentiometric dye, tetramethylrhodamine ethyl ester (TMRE), was used to assess the effect of Mn on astrocytic mitochondrial inner membrane potential (ΔΨ m ). Our studies show that, in a concentration-dependent manner, Mn induces significant (p<0.05) activation of astrocyte caspase-3 and phosphorylated extracellular signal-regulated kinase (p-ERK). Mn treatment (1 and 6 hrs) also significantly (p<0.01) dissipates the ΔΨm in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. These results suggest that activations of astrocytic caspase-3 and ERK are involved in Mn-induced neurotoxicity via mitochondrial-dependent pathways.

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“…In solution, FeSODs form homodimers, 14 while MnSODs form homotetramers. 15 Regarding inhibition, FeSOD is inactivated by H 2 O 2 not by cyanide, while MnSOD is not influenced by either but by azide.…”

mentioning

confidence: 96%

Expression and Purification of Recombinant Superoxide Dismutase (PaSOD) from Psychromonas arctica in Escherichia coli

Na¹,

Im²,

Lee

2011

Bulletin of the Korean Chemical Society

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The psychrophilic bacteria Psychromonas arctica survives at subzero temperatures by having adapted several protective mechanisms against freezing and oxidative stresses. Many reactive oxygen species are likely generated in P. arctica as a result of reduced metabolic turnover rates. A previous study identified the pasod gene for superoxide dismutase from P. arctica using a series of PCR amplifications. Here, upon cloning into a His-tag fused plasmid, the sod gene from P. arctica (pasod) was successfully expressed by IPTG induction. His-tagged PaSOD was subsequently purified by Ni 2+-NTA affinity chromatography. The purified PaSOD exhibited a higher SOD activity than that of Escherichia coli (EcSOD) at all temperatures. The difference in activity between PaSOD and EcSOD becomes even more significant at 4 o C, indicating that PaSOD plays a functional role in the cold adaptation of P. arctica in the Arctic.

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Structure and gene expression of theE. coliMn-superoxide dismutase gene

Cited by 117 publications

References 40 publications

Genetic definition of the Escherichia coli zwf "soxbox," the DNA binding site for SoxS-mediated induction of glucose 6-phosphate dehydrogenase in response to superoxide

Genetic definition of the Escherichia coli zwf "soxbox," the DNA binding site for SoxS-mediated induction of glucose 6-phosphate dehydrogenase in response to superoxide

Mitochondrial-dependent manganese neurotoxicity in rat primary astrocyte cultures

Expression and Purification of Recombinant Superoxide Dismutase (PaSOD) from Psychromonas arctica in Escherichia coli

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