The Role of the Ferric Uptake Regulator (Fur) in Regulation of <i>Helicobacter pylori</i> Iron Uptake

Vliet, Arnoud H. M. van; Stoof, Jeroen; Vlasblom, Ronald; Wainwright, Stuart A.; Hughes, Nicola J.; Kelly, David J.; Bereswill, Stefan; Bijlsma, Jetta J. E.; Hoogenboezem, Theo; Vandenbroucke-Grauls, Christina M. J. E.; Kist, Manfred; Kuipers, Ernst J.; Kusters, Johannes G.

doi:10.1046/j.1523-5378.2002.00088.x

Cited by 94 publications

(142 citation statements)

References 33 publications

Supporting

Mentioning

126

Contrasting

Unclassified

Order By: Relevance

“…The H. pylori strains used in this study were reference strain 26695 (Tomb et al, 1997) and its isogenic fur mutant (Bijlsma et al, 2002;van Vliet et al, 2002a). H. pylori strains were routinely cultured on Dent agar at 37 uC under microaerophilic conditions (10 % CO 2 , 5 % O 2 and 85 % N 2 ).…”

Section: Methodsmentioning

confidence: 99%

“…Iron restriction was achieved by supplementing BBN with desferal (deferoxamine mesylate, Sigma) to a final concentration of 20 mM. Iron-replete conditions were achieved by supplementing desferal-treated BBN with ferric chloride (Sigma) to a final concentration of 100 mM (van Vliet et al, 2002a).…”

Section: Methodsmentioning

confidence: 99%

“…pylori strain 26695 and its isogenic fur mutant were grown in iron-restricted and iron-replete conditions (van Vliet et al, 2002a), and total RNA was isolated from cells grown for 20 h and checked by Northern hybridization using an amiE-specific probe (Fig. 1).…”

Section: Primer Namementioning

confidence: 99%

“…In most bacteria, including H. pylori, the iron-complexed form of Fur binds to promoters of ironuptake genes, thus repressing iron uptake in iron-replete conditions (Delany et al, 2001b;van Vliet et al, 2002a). However, H. pylori Fur has acquired the thus far unique ability also to bind the pfr promoter in its iron-free form, thus repressing expression of iron-storage proteins in ironrestricted conditions Delany et al, 2001a;Waidner et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Transcriptional profiling of Helicobacter pylori Fur- and iron-regulated gene expression

et al. 2005

Self Cite

View full text Add to dashboard Cite

Intracellular iron homeostasis is a necessity for almost all living organisms, since both iron restriction and iron overload can result in cell death. The ferric uptake regulator protein, Fur, controls iron homeostasis in most Gram-negative bacteria. In the human gastric pathogen Helicobacter pylori, Fur is thought to have acquired extra functions to compensate for the relative paucity of regulatory genes. To identify H. pylori genes regulated by iron and Fur, we used DNA array-based transcriptional profiling with RNA isolated from H. pylori 26695 wild-type and fur mutant cells grown in iron-restricted and iron-replete conditions. Sixteen genes encoding proteins involved in metal metabolism, nitrogen metabolism, motility, cell wall synthesis and cofactor synthesis displayed iron-dependent Fur-repressed expression. Conversely, 16 genes encoding proteins involved in iron storage, respiration, energy metabolism, chemotaxis, and oxygen scavenging displayed iron-induced Fur-dependent expression. Several Fur-regulated genes have been previously shown to be essential for acid resistance or gastric colonization in animal models, such as those encoding the hydrogenase and superoxide dismutase enzymes. Overall, there was a partial overlap between the sets of genes regulated by Fur and those previously identified as growth-phase, iron or acid regulated. Regulatory patterns were confirmed for five selected genes using Northern hybridization. In conclusion, H. pylori Fur is a versatile regulator involved in many pathways essential for gastric colonization. These findings further delineate the central role of Fur in regulating the unique capacity of H. pylori to colonize the human stomach.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Primer Namementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transcriptional profiling of Helicobacter pylori Fur- and iron-regulated gene expression

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…To determine the effect of amide substrate on H. pylori, BBN media were supplemented with acrylamide (Sigma) or formamide (Sigma) to final concentrations of 5 and 100 mM, respectively. Iron restriction was achieved by supplementing BBN with desferal to a final concentration of 20 M, whereas iron-repleted conditions were achieved by supplementing desferal-treated BBN with ferric chloride to a final concentration of 100 M (20). Escherichia coli DH5␣ MCR (Invitrogen) was grown aerobically in Luria-Bertani medium at 37°C (27).…”

Section: Methodsmentioning

confidence: 99%

Differential Regulation of Amidase- and Formamidase-mediated Ammonia Production by the Helicobacter pylori Fur Repressor

Vliet¹,

Stoof²,

Poppelaars³

et al. 2003

Journal of Biological Chemistry

Self Cite

130

View full text Add to dashboard Cite

The production of high levels of ammonia allows the human gastric pathogen Helicobacter pylori to survive the acidic conditions in the human stomach. H. pylori produces ammonia through urease-mediated degradation of urea, but it is also able to convert a range of amide substrates into ammonia via its AmiE amidase and AmiF formamidase enzymes. Here data are provided that demonstrate that the iron-responsive regulatory protein Fur directly and indirectly regulates the activity of the two H. pylori amidases. In contrast to other amidase-positive bacteria, amidase and formamidase enzyme activities were not induced by medium supplementation with their respective substrates, acrylamide and formamide. AmiE protein expression and amidase enzyme activity were iron-repressed in H. pylori 26695 but constitutive in the isogenic fur mutant. This regulation was mediated at the transcriptional level via the binding of Fur to the amiE promoter region. In contrast, formamidase enzyme activity was not iron-repressed but was significantly higher in the fur mutant. This effect was not mediated at the transcriptional level, and Fur did not bind to the amiF promoter region. These roles of Fur in regulation of the H. pylori amidases suggest that the H. pylori Fur regulator may have acquired extra functions to compensate for the absence of other regulatory systems.The human pathogen Helicobacter pylori colonizes the mucus layer overlaying the gastric epithelium, thereby causing persistent gastritis, which can develop into peptic ulcer disease and gastric carcinomas (1). H. pylori is able to survive and colonize this hostile acidic niche, aided by the expression of its acid resistance mechanisms (2, 3). One of the major factors contributing to acid resistance of H. pylori is the production of ammonia by its urease enzyme, which is essential for gastric colonization in different animal models (4 -7). However, the role of urease in gastric colonization extends beyond protection against gastric acid, because H. pylori urease mutants are still unable to colonize the gastric mucosa when gastric acid production is abolished with proton pump inhibitors (4).Ammonia is a key component of bacterial nitrogen metabolism, because it is the preferred source of nitrogen for the synthesis of amino acids, pyrimidines, and purines. Ammonia plays a central role in pathogenesis and metabolism of the important human pathogen H. pylori, because it not only serves as nitrogen source (8) but also contributes to epithelial cell damage and apoptosis (9, 10), is involved in chemotactic motility (11), and is required for acid resistance (2, 3). Urea is thought to be the main source of ammonia in the gastric environment, but H. pylori does have alternative pathways for the production of ammonia via amino acid catabolism (12) and via the activity of its two paralogous amidases, AmiE 1 and AmiF (13, 14). Aliphatic amidase (AmiE, EC 3.5.1.4) and formamidase (AmiF, EC 3.5.1.49) catalyze the conversion of amide substrates to the corresponding carboxylic acid and ammonia...

show abstract

The Role of Nickel in Environmental Adaptation of the Gastric Pathogen Helicobacter pylori

Ernst

Vliet

Kist

et al. 2007

Nickel and Its Surprising Impact in Nature

Self Cite

View full text Add to dashboard Cite

The Role of the Ferric Uptake Regulator (Fur) in Regulation of Helicobacter pylori Iron Uptake

Cited by 94 publications

References 33 publications

Transcriptional profiling of Helicobacter pylori Fur- and iron-regulated gene expression

Transcriptional profiling of Helicobacter pylori Fur- and iron-regulated gene expression

Differential Regulation of Amidase- and Formamidase-mediated Ammonia Production by the Helicobacter pylori Fur Repressor

The Role of Nickel in Environmental Adaptation of the Gastric Pathogen Helicobacter pylori

Contact Info

Product

Resources

About