Dataset Information

Proteomic studies of Escherichia coli CFT073 and MG1655

ABSTRACT: Here we dissected a regulatory network directed by the conserved iron homeostasis regulator, Ferric Uptake Regulator (Fur), in uropathogenic E. coli strain CFT073. Comparing anaerobic genome-scale Fur DNA binding, with Fur dependent transcript expression and protein levels of the uropathogen to that of commensal E. coli K-12 strain MG1655, showed that the Fur regulon of the core genome is conserved but also includes genes within the pathogenicity/genetic islands. Unexpectedly, regulons indicative of amino acid limitation and the general stress response were also indirectly activated in the uropathogen fur mutant, suggesting that induction of the Fur regulon increases amino acid demand. Using RpoS levels as a proxy, addition of amino acids mitigated the stress. In addition, iron chelation increased RpoS to the same levels as in the fur mutant. The increased amino acid demand of the fur mutant or iron chelated cells was exacerbated by aerobic conditions, which could be partly explained by the O 2 -dependent synthesis of the siderophore aerobactin, encoded within a pathogenicity island. Taken together, this data suggest in the iron-poor environment of the urinary tract, amino acid availability could play a role in the proliferation of this uropathogen, particularly if there is sufficient O 2 to produce aerobactin.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Escherichia Coli

SUBMITTER: Evgenia Shishkova

LAB HEAD: Joshua J Coon

PROVIDER: PXD017582 | Pride | 2020-05-27

REPOSITORIES: Pride

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Publications

Tailoring a Global Iron Regulon to a Uropathogen.

Banerjee Rajdeep R Weisenhorn Erin E Schwartz Kevin J KJ Myers Kevin S KS Glasner Jeremy D JD Perna Nicole T NT Coon Joshua J JJ Welch Rodney A RA Kiley Patricia J PJ

mBio 20200324 2

Pathogenicity islands and plasmids bear genes for pathogenesis of various <i>Escherichia coli</i> pathotypes. Although there is a basic understanding of the contribution of these virulence factors to disease, less is known about variation in regulatory networks in determining disease phenotypes. Here, we dissected a regulatory network directed by the conserved iron homeostasis regulator, ferric uptake regulator (Fur), in uropathogenic <i>E. coli</i> (UPEC) strain CFT073. Comparing anaerobic geno ...[more]

PMID: 32209682

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Project description:Porphyromonas gingivalis is a major pathogen associated with the microbial biofilm-mediated disease chronic periodontitis. P. gingivalis has an obligate requirement for iron and protoporphyrin IX which it satisfies by transporting heme and iron liberated from the human host. The level of cellular iron in P. gingivalis affects the expression of a distinct iron-associated regulon of 64 genes and low iron invokes an iron sparing response. Iron homeostasis is usually mediated in Gram-negative bacteria at the transcriptional level by the Ferric Uptake Regulator (Fur). There is a single predicted P. gingivalis Fur superfamily orthologue named Har (heme associated regulator) that lacks the conserved metal binding residues found in other Fur orthologues. We show that Har binds both heme and ferrous iron resulting in a conformational change in the protein. Har was unable to complement the Escherichia coli H1780 fur mutant and there was no change in cellular metal content in a P. gingivalis Har mutant compared with the wild-type. The Har regulon of 44 genes is not predicted to play a role in iron homeostasis. Together these data indicated that Har does not regulate iron homeostasis in P. gingivalis. However, Har was required for heme-responsive biofilm development and its regulon overlapped P. gingivalis regulons previously identified after growth in heme limitation or as a homotypic biofilm. P. gingivalis is unique as an iron-dependent Gram-negative bacterium with a single heme-binding Fur superfamily orthologue, Har, that does not regulate iron homeostasis. Paired samples were compared on the same microarray using a two-colour system. A total of 6 paired microarray hybridizations were performed representing 6 biological replicates, where a balanced dye design was used, with the overall analysis including three microarrays where P. gingivalis 33277 samples were labeled with Cy3 and the paired ECR455 samples were labeled with Cy5 and three other microarrays where samples were labeled with the opposite combination of fluorophores.

Project description:Xylella fastidiosa is the etiologic agent of a wide range of plant diseases including citrus variegated chlorosis (CVC), a major threat to the Brazilian citrus industry. Genome sequences of several strains of this phytopathogen are accessible, enabling large-scale functional studies. Transcript levels in different iron availabilities were assessed with DNA microarrays representing 2608 (91.6%) coding sequences (CDS) of X. fastidiosa CVC strain 9a5c. When treated with the iron chelator 2,2-dipyridyl, 193 CDS were considered as up-regulated and 216 as down-regulated. In the presence of 100uM of ferric pyrophosphate, 218 and 256 CDS were considered as up- and down-regulated, respectively. Differential expression for a subset of 44 CDS was further evaluated by reverse transcription - quantitative PCR that showed a Pearson correlation of 0.77 with array results. The CDS differentially expressed upon the iron concentration shift participate in diverse cellular functions. Many CDS involved with regulatory functions, pathogenicity and cell structure, were modulated in both conditions tested suggesting that major changes in cell architecture and metabolism occur when X. fastidiosa cells are exposed to extreme variations in iron concentration. Interestingly, the modulated CDS include those related to colicin V-like bacteriocin synthesis and secretion and to pili/fimbriae functions. We also investigated the contribution of the ferric uptake regulator Fur to the iron regulon of X. fastidiosa. The promoter regions of strain 9a5c genome were screened for putative Fur boxes and candidates were analyzed by electrophoretic mobility shift assays. Taken together, our data support the hypothesis that Fur is not solely responsible for the modulation of the iron regulon of X. fastidiosa and present novel evidence for iron regulation of pathogenicity determinants. Direct comparison between high iron content (100uM ferric pyrophosphate) and control condition. Hybridizations are dye-swaped. There are 2 biological replicates (independent harvest) and 2 technical replicates of each array (L - left and R - right).

Project description:Xylella fastidiosa is the etiologic agent of a wide range of plant diseases including citrus variegated chlorosis (CVC), a major threat to the Brazilian citrus industry. Genome sequences of several strains of this phytopathogen are accessible, enabling large-scale functional studies. Transcript levels in different iron availabilities were assessed with DNA microarrays representing 2608 (91.6%) coding sequences (CDS) of X. fastidiosa CVC strain 9a5c. When treated with the iron chelator 2,2-dipyridyl, 193 CDS were considered as up-regulated and 216 as down-regulated. In the presence of 100uM of ferric pyrophosphate, 218 and 256 CDS were considered as up- and down-regulated, respectively. Differential expression for a subset of 44 CDS was further evaluated by reverse transcription - quantitative PCR that showed a Pearson correlation of 0.77 with array results. The CDS differentially expressed upon the iron concentration shift participate in diverse cellular functions. Many CDS involved with regulatory functions, pathogenicity and cell structure, were modulated in both conditions tested suggesting that major changes in cell architecture and metabolism occur when X. fastidiosa cells are exposed to extreme variations in iron concentration. Interestingly, the modulated CDS include those related to colicin V-like bacteriocin synthesis and secretion and to pili/fimbriae functions. We also investigated the contribution of the ferric uptake regulator Fur to the iron regulon of X. fastidiosa. The promoter regions of strain 9a5c genome were screened for putative Fur boxes and candidates were analyzed by electrophoretic mobility shift assays. Taken together, our data support the hypothesis that Fur is not solely responsible for the modulation of the iron regulon of X. fastidiosa and present novel evidence for iron regulation of pathogenicity determinants. Keywords: stress response; response to iron-depleted condition Direct comparison between low iron content (200uM 2,2-dipyridyl) and control condition. Hybridizations are dye-swaped. There are 2 biological replicates (independent harvest) and 2 technical replicates of each array (L - left and R - right).

Dataset Information

Proteomic studies of Escherichia coli CFT073 and MG1655

Publications

Tailoring a Global Iron Regulon to a Uropathogen.

Similar Datasets

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