scholarly journals Reconstitution of the Trimethylamine Oxide Reductase Regulatory Elements of Shewanella oneidensis in Escherichia coli

2002 ◽  
Vol 184 (5) ◽  
pp. 1262-1269 ◽  
Author(s):  
Stéphanie Gon ◽  
Jean-Claude Patte ◽  
Jean-Philippe Dos Santos ◽  
Vincent Méjean
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Response Regulator ◽  
Regulatory Gene ◽  
Regulatory System ◽  
Regulatory Elements ◽  
Oxygen Control ◽  
E Coli ◽  
Trimethylamine Oxide ◽  
Tmao Reductase

ABSTRACT Several bacteria can grow by using small organic compounds such as trimethylamine oxide (TMAO) as electron acceptors. In Shewanella species, the TMAO reductase respiratory system is encoded by the torECAD operon. We showed that production of the TMAO reductase of S. oneidensis was induced by TMAO and repressed by oxygen, and we noticed that a three-gene cluster (torSTR) encoding a complex two-component regulatory system was present downstream of the torECAD operon. We introduced the torSTR gene cluster into Escherichia coli and showed that this regulatory gene cluster is involved in TMAO induction of the torE promoter but plays no role in the oxygen control. The TorR response regulator was purified, and gel shift and footprinting experiments revealed that TorR binds to a single region located about 70 bases upstream of the transcription start site of the tor structural operon. By deletion analysis, we confirmed that the TorR operator site is required for induction of the tor structural promoter. As the TMAO regulatory system of S. oneidensis is homologous to that of E. coli, we investigated a possible complementation between the TMAO regulatory components of the two bacteria. Interestingly, TorSec, the TMAO sensor of E. coli, was able to transphosphorylate TorRso, the TMAO response regulator of S. oneidensis.

scholarly journals Fumarate Regulation of Gene Expression in Escherichia coli by the DcuSR (dcuSR Genes) Two-Component Regulatory System

1998 ◽  
Vol 180 (20) ◽  
pp. 5421-5425 ◽  
Author(s):  
Evelyn Zientz ◽  
Johannes Bongaerts ◽  
Gottfried Unden
Keyword(s):  
Escherichia Coli ◽  
Histidine Kinase ◽  
Response Regulator ◽  
Regulation Of Gene Expression ◽  
Regulatory System ◽  
E Coli ◽  
Expression In Escherichia Coli ◽  
Two Component ◽  
Genes Encoding ◽  
Periplasmic Domain

ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C4-dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previouslyyjdHG) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR anddcuS genes caused the loss of C4-dicarboxylate-stimulated synthesis of fumarate reductase (frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB (dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C4-dicarboxylate sensing. Regulation by DcuR and DcuS responded to the presence of the C4-dicarboxylates fumarate, succinate, malate, aspartate, tartrate, and maleate. Since maleate is not taken up by the bacteria under these conditions, the carboxylates presumably act from without. Genes of the aerobic C4-dicarboxylate pathway encoding succinate dehydrogenase (sdhCDAB) and the aerobic succinate carrier (dctA) are only marginally or negatively regulated by the DcuSR system. The CitAB two-component regulatory system, which is highly similar to DcuSR, had no effect on C4-dicarboxylate regulation of any of the genes.

scholarly journals Altered Utilization of N-Acetyl-d-Galactosamine by Escherichia coli O157:H7 from the 2006 Spinach Outbreak

2007 ◽  
Vol 190 (5) ◽  
pp. 1710-1717 ◽  
Author(s):  
Amit Mukherjee ◽  
Mark K. Mammel ◽  
J. Eugene LeClerc ◽  
Thomas A. Cebula
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Culture Collection ◽  
Base Substitution ◽  
Phosphotransferase System ◽  
Single Nucleotide ◽  
E Coli ◽  
Single Nucleotide Change ◽  
Phenotype Comparison ◽  
In Silico Analyses

ABSTRACT In silico analyses of previously sequenced strains of Escherichia coli O157:H7, EDL933 and Sakai, localized the gene cluster for the utilization of N-acetyl-d-galactosamine (Aga) and d-galactosamine (Gam). This gene cluster encodes the Aga phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) and other catabolic enzymes responsible for transport and catabolism of Aga. As the complete coding sequences for enzyme IIA (EIIA)Aga/Gam, EIIBAga, EIICAga, and EIIDAga of the Aga PTS are present, E. coli O157:H7 strains normally are able to utilize Aga as a sole carbon source. The Gam PTS complex, in contrast, lacks EIICGam, and consequently, E. coli O157:H7 strains cannot utilize Gam. Phenotypic analyses of 120 independent isolates of E. coli O157:H7 from our culture collection revealed that the overwhelming majority (118/120) displayed the expected Aga+ Gam− phenotype. Yet, when 194 individual isolates, derived from a 2006 spinach-associated E. coli O157:H7 outbreak, were analyzed, all (194/194) displayed an Aga− Gam− phenotype. Comparison of aga/gam sequences from two spinach isolates with those of EDL933 and Sakai revealed a single nucleotide change (G:C→A:T) in the agaF gene in the spinach-associated isolates. The base substitution in agaF, which encodes EIIAAga/Gam of the PTS, changes a conserved glycine residue to serine (Gly91Ser). Pyrosequencing of this region showed that all spinach-associated E. coli O157:H7 isolates harbored this same G:C→A:T substitution. Notably, when agaF + was cloned into an expression vector and transformed into six spinach isolates, all (6/6) were able to grow on Aga, thus demonstrating that the Gly91Ser substitution underlies the Aga− phenotype in these isolates.

scholarly journals SlyA and H-NS Regulate Transcription of the Escherichia coli K5 Capsule Gene Cluster, and Expression of slyA in Escherichia coli Is Temperature-dependent, Positively Autoregulated, and Independent of H-NS

2007 ◽  
Vol 282 (46) ◽  
pp. 33326-33335 ◽  
Author(s):  
David Corbett ◽  
Hayley J. Bennett ◽  
Hamdia Askar ◽  
Jeffrey Green ◽  
Ian S. Roberts
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Regulation Of Transcription ◽  
Temperature Dependent ◽  
Mobility Shift ◽  
E Coli ◽  
Dnase I Footprinting ◽  
Nucleoprotein Complex ◽  
Electrophoretic Mobility Shift Assays

In this paper, we present the first evidence of a role for the transcriptional regulator SlyA in the regulation of transcription of the Escherichia coli K5 capsule gene cluster and demonstrate, using a combination of reporter gene fusions, DNase I footprinting, and electrophoretic mobility shift assays, the dependence of transcription on the functional interplay between H-NS and SlyA. Both SlyA and H-NS bind to multiple overlapping sites within the promoter in vitro, but their binding is not mutually exclusive, resulting in a remodeled nucleoprotein complex. In addition, we show that expression of the E. coli slyA gene is temperature-regulated, positively autoregulated, and independent of H-NS.

scholarly journals The Escherichia coli K-12 NarL and NarP Proteins Insulate the nrf Promoter from the Effects of Integration Host Factor

2006 ◽  
Vol 188 (21) ◽  
pp. 7449-7456 ◽  
Author(s):  
Douglas F. Browning ◽  
David J. Lee ◽  
Alan J. Wolfe ◽  
Jeffrey A. Cole ◽  
Stephen J. W. Busby
Keyword(s):  
Escherichia Coli ◽  
Response Regulator ◽  
Regulatory Region ◽  
Enteric Bacteria ◽  
Integration Host Factor ◽  
Host Factor ◽  
Receptor Protein ◽  
E Coli ◽  
Serovar Typhimurium ◽  
K 12

ABSTRACT The Escherichia coli K-12 nrf operon promoter can be activated fully by the FNR protein (regulator of fumarate and nitrate reduction) binding to a site centered at position −41.5. FNR-dependent transcription is suppressed by integration host factor (IHF) binding at position −54, and this suppression is counteracted by binding of the NarL or NarP response regulator at position −74.5. The E. coli acs gene is transcribed from a divergent promoter upstream from the nrf operon promoter. Transcription from the major acsP2 promoter is dependent on the cyclic AMP receptor protein and is modulated by IHF and Fis binding at multiple sites. We show that IHF binding to one of these sites, located at position −127 with respect to the nrf promoter, has a positive effect on nrf promoter activity. This activation is dependent on the face of the DNA helix, independent of IHF binding at other locations, and found only when NarL/NarP are not bound at position −74.5. Binding of NarL/NarP appears to insulate the nrf promoter from the effects of IHF. The acs-nrf regulatory region is conserved in other pathogenic E. coli strains and related enteric bacteria but differs in Salmonella enterica serovar Typhimurium.

scholarly journals Gene Cluster Responsible for Secretion of and Immunity to Multiple Bacteriocins, the NKR-5-3 Enterocins

2014 ◽  
Vol 80 (21) ◽  
pp. 6647-6655 ◽  
Author(s):  
Naoki Ishibashi ◽  
Kohei Himeno ◽  
Yoshimitsu Masuda ◽  
Rodney Honrada Perez ◽  
Shun Iwatani ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Abc Transporter ◽  
Response Regulator ◽  
Regulatory System ◽  
Content Type ◽  
Expression Studies ◽  
A Genome ◽  
Wide Range ◽  
Close Proximity ◽  
Immunity Genes

ABSTRACTEnterococcus faeciumNKR-5-3, isolated from Thai fermented fish, is characterized by the unique ability to produce five bacteriocins, namely, enterocins NKR-5-3A, -B, -C, -D, and -Z (Ent53A, Ent53B, Ent53C, Ent53D, and Ent53Z). Genetic analysis with a genome library revealed that the bacteriocin structural genes (enkA[ent53A],enkC[ent53C],enkD[ent53D], andenkZ[ent53Z]) that encode these peptides (except for Ent53B) are located in close proximity to each other. This NKR-5-3ACDZ (Ent53ACDZ) enterocin gene cluster (approximately 13 kb long) includes certain bacteriocin biosynthetic genes such as an ABC transporter gene (enkT), two immunity genes (enkIazandenkIc), a response regulator (enkR), and a histidine protein kinase (enkK). Heterologous-expression studies ofenkTand ΔenkTmutant strains showed thatenkTis responsible for the secretion of Ent53A, Ent53C, Ent53D, and Ent53Z, suggesting that EnkT is a wide-range ABC transporter that contributes to the effective production of these bacteriocins. In addition, EnkIaz and EnkIc were found to confer self-immunity to the respective bacteriocins. Furthermore, bacteriocin induction assays performed with the ΔenkRKmutant strain showed that EnkR and EnkK are regulatory proteins responsible for bacteriocin production and that, together with Ent53D, they constitute a three-component regulatory system. Thus, the Ent53ACDZ gene cluster is essential for the biosynthesis and regulation of NKR-5-3 enterocins, and this is, to our knowledge, the first report that demonstrates the secretion of multiple bacteriocins by an ABC transporter.

scholarly journals Fur-Dam Regulatory Interplay at an Internal Promoter of the Enteroaggregative Escherichia coli Type VI Secretion sci1 Gene Cluster

2020 ◽  
Vol 202 (10) ◽  
Author(s):  
Yannick R. Brunet ◽  
Christophe S. Bernard ◽  
Eric Cascales
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Secretion System ◽  
Target Cells ◽  
Type Vi Secretion System ◽  
Content Type ◽  
Internal Promoter ◽  
E Coli ◽  
Type Vi Secretion

ABSTRACT The type VI secretion system (T6SS) is a weapon for delivering effectors into target cells that is widespread in Gram-negative bacteria. The T6SS is a highly versatile machine, as it can target both eukaryotic and prokaryotic cells, and it has been proposed that T6SSs are adapted to the specific needs of each bacterium. The expression of T6SS gene clusters and the activation of the secretion apparatus are therefore tightly controlled. In enteroaggregative Escherichia coli (EAEC), the sci1 T6SS gene cluster is subject to a complex regulation involving both the ferric uptake regulator (Fur) and DNA adenine methylase (Dam)-dependent DNA methylation. In this study, an additional, internal, promoter was identified within the sci1 gene cluster using +1 transcriptional mapping. Further analyses demonstrated that this internal promoter is controlled by a mechanism strictly identical to that of the main promoter. The Fur binding box overlaps the −10 transcriptional element and a Dam methylation site, GATC-32. Hence, the expression of the distal sci1 genes is repressed and the GATC-32 site is protected from methylation in iron-rich conditions. The Fur-dependent protection of GATC-32 was confirmed by an in vitro methylation assay. In addition, the methylation of GATC-32 negatively impacted Fur binding. The expression of the sci1 internal promoter is therefore controlled by iron availability through Fur regulation, whereas Dam-dependent methylation maintains a stable ON expression in iron-limited conditions. IMPORTANCE Bacteria use weapons to deliver effectors into target cells. One of these weapons, the type VI secretion system (T6SS), assembles a contractile tail acting as a spring to propel a toxin-loaded needle. Its expression and activation therefore need to be tightly regulated. Here, we identified an internal promoter within the sci1 T6SS gene cluster in enteroaggregative E. coli. We show that this internal promoter is controlled by Fur and Dam-dependent methylation. We further demonstrate that Fur and Dam compete at the −10 transcriptional element to finely tune the expression of T6SS genes. We propose that this elegant regulatory mechanism allows the optimum production of the T6SS in conditions where enteroaggregative E. coli encounters competing species.

CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli

2019 ◽  
Vol 65 (9) ◽  
pp. 691-702 ◽  
Author(s):  
Yi Gou ◽  
Weiqi Liu ◽  
Jing Jing Wang ◽  
Ling Tan ◽  
Bin Hong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Motility ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Signal Transmission ◽  
Bacterial Motility ◽  
Type I ◽  
E Coli ◽  
Real Time Quantitative Pcr ◽  
In The Wild

Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.

scholarly journals Increased Mutation Frequency in Redox-Impaired Escherichia coli Due to RelA- and RpoS-Mediated Repression of DNA Repair

2010 ◽  
Vol 76 (16) ◽  
pp. 5463-5470 ◽  
Author(s):  
Amarjeet Singh ◽  
Anis Karimpour-Fard ◽  
Ryan T. Gill
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Regulatory Gene ◽  
Stringent Response ◽  
Anaerobic Growth ◽  
E Coli ◽  
Direct Measurements ◽  
Order Of Magnitude

ABSTRACT Balancing of reducing equivalents is a fundamental issue in bacterial metabolism and metabolic engineering. Mutations in the key metabolic genes ldhA and pflB of Escherichia coli are known to stall anaerobic growth and fermentation due to a buildup of intracellular NADH. We observed that the rate of spontaneous mutation in E. coli BW25113 (ΔldhA ΔpflB) was an order of magnitude higher than that in wild-type (WT) E. coli BW25113. We hypothesized that the increased mutation frequency was due to an increased NADH/NAD+ ratio in this strain. Using several redox-impaired strains of E. coli and different redox conditions, we confirmed a significant correlation (P < 0.01) between intracellular-NADH/NAD+ ratio and mutation frequency. To identify the genetic basis for this relationship, whole-genome transcriptional profiles were compared between BW25113 WT and BW25113 (ΔldhA ΔpflB). This analysis revealed that the genes involved in DNA repair were expressed at significantly lower levels in BW25113 (ΔldhA ΔpflB). Direct measurements of the extent of DNA repair in BW25113 (ΔldhA ΔpflB) subjected to UV exposure confirmed that DNA repair was inhibited. To identify a direct link between DNA repair and intracellular-redox ratio, the stringent-response-regulatory gene relA and the global-stress-response-regulatory gene rpoS were deleted. In both cases, the mutation frequencies were restored to BW25113 WT levels.

scholarly journals Effects of ISSo2 Insertions in Structural and Regulatory Genes of the Trimethylamine Oxide Reductase of Shewanella oneidensis

2003 ◽  
Vol 185 (6) ◽  
pp. 2042-2045 ◽  
Author(s):  
Christophe Bordi ◽  
Chantal Iobbi-Nivol ◽  
Vincent Méjean ◽  
Jean-Claude Patte
Keyword(s):  
Growth Analysis ◽  
Response Regulator ◽  
Shewanella Oneidensis ◽  
Regulatory Genes ◽  
Trimethylamine Oxide ◽  
Tmao Reductase

ABSTRACT We have isolated three Shewanella oneidensis mutants specifically impaired in trimethylamine oxide (TMAO) respiration. The mutations arose from insertions of an ISSo2 element into torA, torR, and torS, encoding, respectively, the TMAO reductase TorA, the response regulator TorR, and the sensor TorS. Although TorA is not the sole enzyme reducing TMAO in S. oneidensis, growth analysis showed that it is the main respiratory TMAO reductase. Use of a plasmid-borne torE′-lacZ fusion confirmed that the TorS-TorR phosphorelay mediates TMAO induction of the torECAD operon.

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