YlaN is an iron binding protein that is required to relieve Fur-mediated gene expression
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ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE228225 | GEO | 2026/03/01
REPOSITORIES: GEO
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Project description:Iron (Fe) is a trace nutrient required by nearly all organisms. As a result of the demand for Fe and the toxicity of non-chelated cytosolic ionic Fe, regulatory systems have evolved to tightly balance Fe acquisition and usage while limiting overload. In most bacteria, including the mammalian pathogen Staphylococcus aureus, the ferric uptake regulator (Fur) is the primary transcriptional regulator that controls the transcription of genes that code for Fe uptake and utilization proteins. Fpa (formaly YlaN) was demonstrated to be essential in Bacillus subtilis unless excess Fe is added to the growth medium, suggesting a role in Fe homeostasis. Here, we demonstrate that Fpa is expendable in S. aureus; however, Fpa became essential upon Fe deprivation. A null fur allele bypassed the essentiality of Fpa. The absence of Fpa nearly abolished the derepression of Fur-dependent transcription during Fe limitation. Bioinformatic analyses suggest that fpa was recruited to Gram positive bacteria and once acquired was maintained in the genome as it co-evolved with Fur. Consistent with a role for Fpa in influencing Fur-dependent regulation, Fpa and Fur interacted in vivo and Fpa inhibits the DNA binding ability of Fur in vitro. Fpa bound Fe(II) in vitro using oxygen or nitrogen ligands with an association constant that is consistent with a physiological role in Fe sensing and/or buffering. These findings have led to a model wherein Fpa is an Fe(II) binding protein that influences Fur-dependent regulation through direct interaction.
2025-05-06 | PXD051930 | Pride
Project description:Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for survival. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. Previous work has identified a small RNA, HrrF, that is Fur-regulated in NTHi 86-028NPrpsL.To understand the contribution made by HrrF to gene regulation in NTHi, hrrF was deleted in the NTHi strain 86-028NPrpsL∆fur. Using RNA-Seq, we identified protein-encoding genes whose expression was repressed or activated by HrrF.
2014-08-26 | GSE58891 | GEO
Project description:Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for persistence. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. To understand the regulation of iron homeostasis in NTHi, fur was deleted in the prototypic NTHi clinical isolate, 86-028NP. Using an NTHi-specific microarray, we identified genes whose expression was repressed or activated by Fur.
2013-02-05 | GSE39874 | GEO
Project description:Global tranascriptional profiling of Bacillus subtilis cells comparing fur mutant to mutants of the iron-sparing response: fur fsrA double mutant, fur fbpAB triple mutant, fur fbpC double mutant, and fur fbpABC quadruple mutant Abstract of associated manuscript: The Bacillus subtilis ferric uptake regulator (Fur) protein is the major sensor of cellular iron status. When iron is limiting for growth, derepression of the Fur regulon increases the cellular capacity for iron uptake and mobilizes an iron-sparing response mediated, in large part, by a small non-coding RNA named FsrA. FsrA functions together with three small, basic proteins (FbpABC) to repress many "low-priority" iron-containing enzymes. We have used transcriptome analyses to define the scope of the iron-sparing response and to define subsets of genes dependent on either FbpAB or FbpC for their repression. Enzymes of the tricarboxylic acid cycle, including both aconitase and succinate dehydrogenase, are major targets of FsrA-mediated repression and, as a consequence, flux through this pathway is significantly decreased under iron limitation. FsrA also mediates a physiologically significant repression of iron-sulfur containing enzymes required for ammonium assimilation (the GltAB glutamate synthase) and catabolism of lactic acid (LutABC). Repression of the lutABC operon requires both FsrA and FbpB which supports a model in which the Fbp proteins function to enable repression of subsets of the FsrA regulon.
2011-02-19 | GSE27416 | GEO
Project description:Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for persistence. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. To understand the regulation of iron homeostasis in NTHi, fur was deleted in the prototypic NTHi clinical isolate, 86-028NP. Using an NTHi-specific microarray, we identified genes whose expression was repressed or activated by Fur. These data comprise transcriptional anaylses of a pediatric isolate of NTHi (86-028NP) an rpsL mutant of 86-028NP, a fur mutant of 86-028NP and a fur mutant of 86-028NPrpsL. NTHi parent and fur mutant strains were grown in defined medium containing 10 M-BM-5g /ml human hemoglobin to mid-log phase. Cells were then harvested and RNA extracted. A total of four biological replicates were generated for these analyses.
2013-02-05 | E-GEOD-39874 | biostudies-arrayexpress
Project description:In the alpha subclass of proteobacteria iron homeostasis is controlled by diverse iron responsive regulators. Caulobacter crescentus, an important freshwater α-proteobacterium, uses the ferric uptake repressor (Fur) for such purpose. However, the impact of the iron availability on the C. crescentus transcriptome and an overall perspective of the regulatory networks involved remain unknown. In this work we report the identification of iron-responsive and Fur-regulated genes in C. crescentus using microarray-based global transcriptional analyses. We identify 46 genes that were strongly upregulated both by mutation of fur and by iron limitation condition. Among them, there are genes involved in iron uptake (four TonB dependent receptor gene clusters, feoAB), riboflavin biosynthesis and some genes encoding hypothetical proteins. Most of these genes are associated with Fur binding sites, implicating them as direct targets of Fur-mediated repression. These data were validated by β-galactosidase and EMSA assays for two operons encoding putative transporters. The role of Fur as a positive regulator is also evident, given that 50 genes were downregulated both by mutation of fur and under low-iron condition. As expected, this group includes many genes involved in energy metabolism, mostly iron-using enzymes. Surprisingly, are also included in this group many genes encoding TonB dependent receptors and the genes fixK, fixT and ftrB encoding an oxygen signaling network required for growth during hypoxia. Bioinformatics analyses performed in the promoters of these genes suggest that positive regulation by Fur is mainly indirect. In addition to the Fur modulon, iron limitation altered expression of more 103 genes, including upregulation of genes involved in Fe-S cluster assembly, oxidative stress and heat shock response, as well as downregulation of genes implicated in amino acid metabolism, chemotaxis and motility. Altogether, our results showed that adaptation of C. crescentus to iron limitation involves increasing the transcription of iron-acquisition systems and decreasing the production of iron-using proteins as a general strategy
2013-08-15 | GSE45653 | GEO
Project description:In the alpha subclass of proteobacteria iron homeostasis is controlled by diverse iron responsive regulators. Caulobacter crescentus, an important freshwater α-proteobacterium, uses the ferric uptake repressor (Fur) for such purpose. However, the impact of the iron availability on the C. crescentus transcriptome and an overall perspective of the regulatory networks involved remain unknown. In this work we report the identification of iron-responsive and Fur-regulated genes in C. crescentus using microarray-based global transcriptional analyses. We identify 46 genes that were strongly upregulated both by mutation of fur and by iron limitation condition. Among them, there are genes involved in iron uptake (four TonB dependent receptor gene clusters, feoAB), riboflavin biosynthesis and some genes encoding hypothetical proteins. Most of these genes are associated with Fur binding sites, implicating them as direct targets of Fur-mediated repression. These data were validated by β-galactosidase and EMSA assays for two operons encoding putative transporters. The role of Fur as a positive regulator is also evident, given that 50 genes were downregulated both by mutation of fur and under low-iron condition. As expected, this group includes many genes involved in energy metabolism, mostly iron-using enzymes. Surprisingly, are also included in this group many genes encoding TonB dependent receptors and the genes fixK, fixT and ftrB encoding an oxygen signaling network required for growth during hypoxia. Bioinformatics analyses performed in the promoters of these genes suggest that positive regulation by Fur is mainly indirect. In addition to the Fur modulon, iron limitation altered expression of more 103 genes, including upregulation of genes involved in Fe-S cluster assembly, oxidative stress and heat shock response, as well as downregulation of genes implicated in amino acid metabolism, chemotaxis and motility. Altogether, our results showed that adaptation of C. crescentus to iron limitation involves increasing the transcription of iron-acquisition systems and decreasing the production of iron-using proteins as a general strategy Two experimental procedures, each of them performed in two replicates. A total of four independent biological samples were used
2013-08-15 | E-GEOD-45653 | biostudies-arrayexpress
Project description:Fur is a transcriptional regulator whose activity is dependent on Fe(II) concentrations. Chromatin immunoprecipitation (ChIP) coupled to microarray analysis allowed for the identification of Fur binding sites within the G. sulfurreducens genome.
2014-03-10 | GSE54305 | GEO
Project description:Ferric uptake regulator (Fur) is the major regulator of iron acquisition in Escherichia coli and other bacteria. In the present study, the role of Fur in anaerobic S. enterica serovar Typhimurium was determined by transcriptome analysis, reporter assays, and enzymatic assays. In anaerobic Δfur, 298 genes were differentially expressed. In general, Fur repressed genes required for iron acquisition/storage, metabolism, electron transport, oxidative/nitrosative stress, and modulators of virulence. There were 73 genes whose expression required Fur, eleven of which contain a putative Fur box 5‟ of the gene. Transcription of sodA was >9-fold higher in Δfur but there was no corresponding increase in the activity of SodA.
2011-10-14 | GSE18441 | GEO
Project description:Bacterial transcription factors (TFs) regulate gene expression to adapt to changing environments; when combined, the TF’s regulatory actions comprise transcriptional regulatory networks (TRNs). The chromatin immunoprecipitation (ChIP) assay is the major contemporary method for mapping in vivo protein-DNA interactions in the genome. It enables the genome-wide study of transcription factor binding sites (TFBSs) and gene regulation. Although rapidly accumulating publicly-available ChIP data are a valuable resource for the study of gene regulation, there are no full datasets of ferric uptake regulator (Fur) across gram-negative bacteria. Here, we present the genome-wide binding for Fur in multi-species.
2021-08-15 | GSE181770 | GEO