Expression Analysis of the nrdHIEF Operon fromEscherichia coli

Monje-Casas, Fernando; Jurado, Juan; Prieto‐Álamo, María‐José; Holmgren, Arne; Pueyo, Carmen

doi:10.1074/jbc.m011728200

Cited by 93 publications

(48 citation statements)

References 40 publications

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“…This finding suggests that, in metaland nutrient-rich media, MtsR enhances its own expression and represses that of mtsABC. Also significantly up-regulated were genes encoding an alkyl hydroperoxide reductase (ahpCA) and ribonucleotide diphosphate reductase (nrdEIF), both found to be up-regulated in response to oxidative stress in other bacterial pathogens (29,30). Of note, the growth curves of strain MGAS9887 and MGAS315 were identical in THY broth (Fig.…”

Section: Expression Microarray Analysis Of Subclone 5 Strain Mgas9887mentioning

confidence: 74%

Molecular genetic anatomy of inter- and intraserotype variation in the human bacterial pathogen group A Streptococcus

Beres

Richter

Nagiec

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

201

177

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In recent years we have studied the relationship between strain genotypes and patient phenotypes in group A Streptococcus (GAS), a model human bacterial pathogen that causes extensive morbidity and mortality worldwide. We have concentrated our efforts on serotype M3 organisms because these strains are common causes of pharyngeal and invasive infections, produce unusually severe invasive infections, and can exhibit epidemic behavior. Our studies have been hindered by the lack of genome-scale phylogenies of multiple GAS strains and whole-genome sequences of multiple serotype M3 strains recovered from individuals with defined clinical phenotypes. To remove some of these impediments, we sequenced to closure the genome of four additional GAS strains and conducted comparative genomic resequencing of 12 contemporary serotype M3 strains representing distinct genotypes and phenotypes. Serotype M3 strains are a single phylogenetic lineage. Strains from asymptomatic throat carriers were significantly less virulent for mice than sterile-site isolates and evolved to a less virulent phenotype by multiple genetic pathways. Strain persistence or extinction between epidemics was strongly associated with presence or absence, respectively, of the prophage encoding streptococcal pyrogenic exotoxin A. A serotype M3 clone significantly underrepresented among necrotizing fasciitis cases has a unique frameshift mutation that truncates MtsR, a transcriptional regulator controlling expression of genes encoding ironacquisition proteins. Expression microarray analysis of this clone confirmed significant alteration in expression of genes encoding iron metabolism proteins. Our analysis provided unprecedented detail about the molecular anatomy of bacterial strain genotypepatient phenotype relationships.carrier ͉ epidemic ͉ genomic resequencing ͉ SNP ͉ phylogeny M icrobial epidemics have repeatedly altered the course of history by decimating human populations, killing domesticated animals, and blighting crops. Despite the impact of these destructive events, we know relatively little about the evolutionary genetic events contributing to bacterial strain emergence and diversification within and between epidemic waves. Also poorly understood is the molecular basis of intraspecies variation in disease phenotype. The recent confluence of genome sequencing and development of high-throughput techniques to interrogate genetic polymorphisms in large samples of strains now permits these topics to be studied at the individual nucleotide level.Group A Streptococcus (GAS) infects humans worldwide and causes an array of diseases ranging from superficial infections such as pharyngitis to fulminant invasive infections characterized by high morbidity and mortality (1, 2). In recent years, we have used serotype M3 GAS strains as model pathogens for studying the molecular processes contributing to clone emergence, epidemic waves, and genotype-phenotype relationships (M protein is a highly polymorphic cell-surface molecule that is antiphagocytic and forms the bas...

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Section: Expression Microarray Analysis Of Subclone 5 Strain Mgas9887mentioning

confidence: 74%

Molecular genetic anatomy of inter- and intraserotype variation in the human bacterial pathogen group A Streptococcus

Beres

Richter

Nagiec

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

201

177

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“…These findings suggest that Grx2 is not regulated by the antioxidant defense orchestrated by OxyR but from an alternative system. Another potential antioxidant not regulated by OxyR is the thioredoxin-like protein NrdH, which is also up-regulated in an oxyR Ϫ strain (44). A global analysis of E. coli transcripts up-regulated by hydrogen peroxide did not include Grx2 (Grx3 or Trx1), but Grx1 and Trx2 (45).…”

Section: Fig 10 Extracellular Protein Concentration In Mc4100 Andmentioning

confidence: 99%

Expression of Escherichia coli Glutaredoxin 2 Is Mainly Regulated by ppGpp and ςS

Potamitou

Neubauer

Holmgren

et al. 2002

Journal of Biological Chemistry

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Escherichia coli glutaredoxin 2 (Grx2, encoded by grxB) differs greatly from the other two glutaredoxins in structure and catalytic properties. In a wild type strain, levels of Grx2 increased 3-fold in the stationary phase (up to 8 g/mg). Guanosine-3,5-tetraphoshate (ppGpp) and S , which regulate the transcription of genes in the stationary phase, dramatically affected the expression of Grx2. spoTrelA null mutants, lacking ppGpp, had very low levels of Grx2, while overproduction of full-length RelA or valine-induced starvation of isoleucine, both conditions elevating ppGpp levels, resulted in elevation of Grx2. Null mutants for the S -specific protease ClpP, which have higher levels of S , exhibited a 3-fold Grx2 increase.S in trans also increased the levels of Grx2. Therefore the stationary phase expression of Grx2 is determined by the S -bound form of RNA polymerase in connection with ppGpp, while basal levels should be attributed to 70 -RNA polymerase holoenzyme. Osmotic pressure and cAMP also affected the expression of Grx2, presumably via S . Furthermore, Grx2 levels were elevated in an oxyR ؊ strain. In accordance with the role of Grx2 as a stationary phase protein, null mutants for grxB were shown to lyse under starvation conditions and exhibited a distorted morphology.

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“…Trx2 levels were elevated 2-3-fold in the trxAgrxAgrxBgrxC null mutant. Another system that could partially compensate for RR1a is the RR1b system from the nrdHIEF operon (14). This particular operon is highly transcribed in minimal media (14), where the thymidine incorporation measurements were performed.…”

Section: Levels Of Redoxins In Different Geneticmentioning

confidence: 99%

“…Grx1 is regulated at the transcriptional level, where a dramatic increase in the mRNA level was observed in a strain lacking both Trx1 and GSH (13). Apart from changes within the RR1a system, transcription of the aerobic ribonucleotide reductase 1b (RR1b) from the nrdHIEF operon is increased over 100-fold in strains lacking both Trx1 and Grx1 (14). The transcription factor OxyR regulates the transcription of GR, Grx1, and Trx2 under oxidative conditions (15)(16)(17).…”

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confidence: 99%

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Protein Levels of Escherichia coli Thioredoxins and Glutaredoxins and Their Relation to Null Mutants, Growth Phase, and Function

Potamitou

Holmgren

Vlamis-Gardikas

2002

Journal of Biological Chemistry

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Levels of Escherichia coli thioredoxin 1 (Trx1), Trx2, glutaredoxin 1 (Grx1), Grx2, and Grx3 have been determined by novel sensitive sandwich enzyme-linked immunosorbent assay. In a wild type strain, levels of Trx1 increased from the exponential to the stationary phase of growth (1.5-fold to 3400 ng/mg), as did levels of Grx2 (from ϳ2500 to ϳ8000 ng/mg). Grx3 and Trx2 levels were quite stable during growth (ϳ4500 and ϳ200 ng/mg, respectively). Grx1 levels decreased from ϳ600 ng/mg at the exponential phase to ϳ285 ng/mg at the stationary phase. A large elevation of Grx1 (20 -30-fold), was observed in null mutants for the thioredoxin system whereas levels of the other redoxins in all combinations of examined null mutants barely exceeded a 2-3-fold increase. Measurements of thymidine incorporation in newly synthesized DNA suggested that mainly Grx1 and, to a lesser extent, Trx1 contribute to the reduction of ribonucleotides. All glutaredoxin species were elevated in catalase-deficient strains, implying an antioxidant role for the glutaredoxins. Trx1, Trx2, and Grx1 levels increased after exposure to hydrogen peroxide and decreased after exposure to mercaptoethanol. The levels of Grx2 and Grx3 behaved exactly the opposite, suggesting that the transcription factor OxyR does not regulate their expression.Escherichia coli employs two separate pathways that use NADPH to reduce cytosolic disulfides: the thioredoxin and the glutaredoxin systems. The thioredoxin system consists of thioredoxin reductase and thioredoxins 1 and 2 (Trx1 and Trx2).

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Expression Analysis of the nrdHIEF Operon fromEscherichia coli

Cited by 93 publications

References 40 publications

Molecular genetic anatomy of inter- and intraserotype variation in the human bacterial pathogen group A Streptococcus

Molecular genetic anatomy of inter- and intraserotype variation in the human bacterial pathogen group A Streptococcus

Expression of Escherichia coli Glutaredoxin 2 Is Mainly Regulated by ppGpp and ςS

Protein Levels of Escherichia coli Thioredoxins and Glutaredoxins and Their Relation to Null Mutants, Growth Phase, and Function

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