<i>Bacillus subtilis</i> contains multiple Fur homologues: identification of the iron uptake (Fur) and peroxide regulon (PerR) repressors

Bsat, Nada; Herbig, Andrew F.; Casillas-Martínez, Lilliam; Setlow, Peter; Helmann, John D.

doi:10.1046/j.1365-2958.1998.00921.x

Cited by 371 publications

(447 citation statements)

References 58 publications

(98 reference statements)

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“…However, its distribution is not limited to Grampositive bacteria (69,78,91,112), and in several cases, PerR is found along with OxyR (36,37,111,118). In Bacillus subtilis, PerR regulates itself (30) and other genes, including those involved in oxidative stress defense (katA, ahpCF, mrgA) (10,14), metal homeostasis (zosA, fur, hemAXCDBL) (14,30,31), and surfactant production (srfA) (41), in response to peroxide exposure. As with OxyR, PerR homologs in other organisms tend to regulate similar classes of genes (7,8,36,48,79,91,117).…”

Section: Perrmentioning

confidence: 99%

Peroxide‐Sensing Transcriptional Regulators in Bacteria

Dubbs

Mongkolsuk

2016

Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria

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The ability to maintain intracellular concentrations of toxic reactive oxygen species (ROS) within safe limits is essential for all aerobic life forms. In bacteria, as well as other organisms, ROS are produced during the normal course of aerobic metabolism, necessitating the constitutive expression of ROS scavenging systems. However, bacteria can also experience transient high-level exposure to ROS derived either from external sources, such as the host defense response, or as a secondary effect of other seemingly unrelated environmental stresses. Consequently, transcriptional regulators have evolved to sense the levels of ROS and coordinate the appropriate oxidative stress response. Three well-studied examples of these are the peroxide responsive regulators OxyR, PerR, and OhrR. OxyR and PerR are sensors of primarily H 2 O 2 , while OhrR senses organic peroxide (ROOH) and sodium hypochlorite (NaOCl). OxyR and OhrR sense oxidants by means of the reversible oxidation of specific cysteine residues. In contrast, PerR senses H 2 O 2 via the Fe-catalyzed oxidation of histidine residues. These transcription regulators also influence complex biological phenomena, such as biofilm formation, the evasion of host immune responses, and antibiotic resistance via the direct regulation of specific proteins.

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Section: Perrmentioning

confidence: 99%

Peroxide‐Sensing Transcriptional Regulators in Bacteria

Dubbs

Mongkolsuk

2016

Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria

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“…As Fe accumulates within the cell, Fe 2+ binds to the carboxy terminus of the regulatory protein; thereby, the protein acquires structural conformation capable of binding target DNA sequences, such as Fur boxes. Experimental evidence indicates that the mere presence of a Fur box within a promoter region subjects the adjacent genes to Furregulation (Bsat et al, 1998;Calderwood and Meklanos, 1988;vanVliet et al, 1999;Bsat et al, 1999;Leoni et al, 2000). Mutants lacking Fur exhibit defective regulation in numerous cellular responses such as amino acid synthesis (Weisbach and Bsat, 1991), purine nucleotide synthesis (He et al, 1993), and toxin production (Tai et al, 1990), suggesting that Fur is a global regulator and not restricted solely to Fe regulation.…”

Section: F Metalloregulation Of Oxidative Stressmentioning

confidence: 99%

“…This 24-bp sequence, referred to as a "Per box," has homology to a Fur box. The completed B. subtilis genome sequence revealed three fur homologs: ydkL, yqfV, and ygaG (Bsat et al, 1998). Like fur mutants, the ydkL mutant constitutively expresses genes for siderophore biosynthesis and Fe uptake.…”

Section: F Metalloregulation Of Oxidative Stressmentioning

confidence: 99%

“…In gram-positive bacteria, another Fur-related protein has emerged as a regulator of peroxide stress (Chen et al, 1995;Bsat et al, 1998, vanVliet et al, 1999Horsburgh et al, 2001). Studies in B. subtilis with H2O2 treatment and metal ion limitation showed an increased expression of catalase, alkyl hydroperoxidase, and a Mn-response protein (Dowds, 1994).…”

Section: Identified E Colimentioning

confidence: 99%

“…Analysis of the promoters of these genes identified a consensus sequence similar to a Fur box; this sequence was termed a Per box. Bsat et al (1998) found that the gene product of ydkL demonstrated Fe uptake-repressive activities as well as structural similarities to Fur.…”

Section: Identified E Colimentioning

confidence: 99%

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Characterization of secA-sod operon in Borrellia burgdorferi.

Nichols¹

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Borrelia burgdorferi, the causative agent of Lyme disease, has been characterized as a microaerophilic spirochete. O2 consumption and utilization potentially yield reactive oxygen intermediates, such as superoxide, hydroxyl radicals, and hydrogen peroxide. This study investigated the expression of the sod gene, which encodes the only, identified oxidative defense mechanism in B. burgdorferi. Using primer extension analysis and RT-PCR, it was found that sod and secA are organized as a single transcriptional unit under the control of σ 70 -like promoter upstream of the secA open reading frame. Generally, gene expression decreases with increased distance from the promoter; however, secA expression was observed to be relatively lower amounts than sod. Both genes were expressed in all phases of growth, with greatest expression observed in stationary phase. Because transcription of most sod genes is tightly regulated by iron concentration, the secA-sod gene expression was analyzed in borrelial cells grown in varying amounts of metal. Ironrestriction did not significantly affect growth nor did it affect transcription of secA or sod.Likewise, no major differences in transcription were observed with restricting or supplementing media with manganese. To test the possibility that the borrelial SOD may function with either iron or manganese as a cofactor as in cambialistic SODs, SOD activity was assayed and the highest activity was observed in increased manganese concentrations.Protein expression profiles of Sh-2-82 cultured in metal-defined media were investigated by one-and two-dimensional gel electrophoresis. Approximately 15 proteins were differentially expressed in response to metal concentration. iv ACKNOWLEDGMENTS

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