scholarly journals FliT Acts as an Anti-FlhD2C2 Factor in the Transcriptional Control of the Flagellar Regulon in Salmonella enterica Serovar Typhimurium

2006 ◽  
Vol 188 (18) ◽  
pp. 6703-6708 ◽  
Author(s):  
Shouji Yamamoto ◽  
Kazuhiro Kutsukake
Keyword(s):  
Rna Polymerase ◽  
Western Blotting ◽  
Salmonella Enterica ◽  
Transcriptional Control ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Flagellar Gene ◽  
Gene Products ◽  
Serovar Typhimurium ◽  
Class 1 ◽  
Flagellar Regulon

ABSTRACT Flagellar operons are divided into three classes with respect to their transcriptional hierarchy in Salmonella enterica serovar Typhimurium. The class 1 gene products FlhD and FlhC act together in an FlhD2C2 heterotetramer, which binds upstream of the class 2 promoters to facilitate binding of RNA polymerase. Class 2 expression is known to be enhanced by a disruption mutation in a flagellar gene, fliT. In this study, we purified FliT protein in a His-tagged form and showed that the protein prevented binding of FlhD2C2 to the class 2 promoter and inhibited FlhD2C2-dependent transcription. Pull-down and far-Western blotting analyses revealed that the FliT protein was capable of binding to FlhD2C2 and FlhC and not to FlhD alone. We conclude that FliT acts as an anti-FlhD2C2 factor, which binds to FlhD2C2 through interaction with the FlhC subunit and inhibits its binding to the class 2 promoter.

scholarly journals Transcription Modulation of Salmonella enterica Serovar Typhimurium Promoters by Sub-MIC Levels of Rifampin

2006 ◽  
Vol 188 (22) ◽  
pp. 7988-7991 ◽  
Author(s):  
Grace Yim ◽  
Fernando de la Cruz ◽  
George B. Spiegelman ◽  
Julian Davies
Keyword(s):  
Rna Polymerase ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory Proteins ◽  
Global Regulators ◽  
Serovar Typhimurium ◽  
Transcription Modulation

ABSTRACT Promoter-lux fusions that showed rifampin-modulated transcription were identified from a Salmonella enterica serovar Typhimurium 14028 reporter library. The transformation of a subset of fusions into mutants that lacked one of six global regulatory proteins or were rifampin resistant showed that transcription modulation was independent of the global regulators, promoter specific, and dependent on the interaction of rifampin with RNA polymerase.

scholarly journals RtsA and RtsB Coordinately Regulate Expression of the Invasion and Flagellar Genes in Salmonella enterica Serovar Typhimurium

2003 ◽  
Vol 185 (17) ◽  
pp. 5096-5108 ◽  
Author(s):  
Craig D. Ellermeier ◽  
James M. Slauch
Keyword(s):  
Salmonella Enterica ◽  
Defense Mechanisms ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory Protein ◽  
Infection Process ◽  
Serovar Typhimurium ◽  
Flagellar Regulon ◽  
Direct Binding ◽  
Random Screen ◽  
Flagellar Genes

ABSTRACT Salmonella enterica serovar Typhimurium encounters numerous host environments and defense mechanisms during the infection process. The bacterium responds by tightly regulating the expression of virulence genes. We identified two regulatory proteins, termed RtsA and RtsB, which are encoded in an operon located on an island integrated at tRNAPheU in S. enterica serovar Typhimurium. RtsA belongs to the AraC/XylS family of regulators, and RtsB is a helix-turn-helix DNA binding protein. In a random screen, we identified five RtsA-regulated fusions, all belonging to the Salmonella pathogenicity island 1 (SPI1) regulon, which encodes a type III secretion system (TTSS) required for invasion of epithelial cells. We show that RtsA increases expression of the invasion genes by inducing hilA expression. RtsA also induces expression of hilD, hilC, and the invF operon. However, induction of hilA is independent of HilC and HilD and is mediated by direct binding of RtsA to the hilA promoter. The phenotype of an rtsA null mutation is similar to the phenotype of a hilC mutation, both of which decrease expression of SPI1 genes approximately twofold. We also show that RtsA can induce expression of a SPI1 TTSS effector, slrP, independent of any SPI1 regulatory protein. RtsB represses expression of the flagellar genes by binding to the flhDC promoter region. Repression of the positive activators flhDC decreases expression of the entire flagellar regulon. We propose that RtsA and RtsB coordinate induction of invasion and repression of motility in the small intestine.

scholarly journals The ClpXP ATP-Dependent Protease Regulates Flagellum Synthesis in Salmonella enterica Serovar Typhimurium

2002 ◽  
Vol 184 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Toshifumi Tomoyasu ◽  
Tomiko Ohkishi ◽  
Yoshifumi Ukyo ◽  
Akane Tokumitsu ◽  
Akiko Takaya ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Proteome Analysis ◽  
Fourfold Increase ◽  
Master Regulators ◽  
Serovar Typhimurium ◽  
Flagellar Filament ◽  
Flagellar Regulon ◽  
Flagellar Proteins

ABSTRACT The ClpXP protease is a member of the ATP-dependent protease family and plays a dynamic role in the control of availability of regulatory proteins and the breakdown of abnormal and misfolded proteins. The proteolytic activity is rendered by the ClpP component, while the substrate specificity is determined by the ClpX component that has ATPase activity. We describe here a new role of the ClpXP protease in Salmonella enterica serovar Typhimurium in which ClpXP is involved in the regulation of flagellum synthesis. Cells deleted for ClpXP show “hyperflagellate phenotype,” exhibit overproduction of the flagellar protein, and show a fourfold increase in the rate of transcription of the fliC encoding flagellar filament. The assay for promoter activity of the genes responsible for expression of the fliC showed that the depletion of ClpXP results in dramatic enhancement of the expression of the fliA encoding sigma factor ς28, leaving the expression level of the flhD master operon lying at the top of the transcription hierarchy of flagellar regulon almost normal. These results suggest that the ClpXP may be responsible for repressing the expression of flagellar regulon through the control of the FlhD/FlhC master regulators at the posttranscriptional and/or posttranslational levels. Proteome analysis of proteins secreted from the mutant cells deficient for flhDC and clpXP genes demonstrated that the ΔflhD mutation abolished the enhanced effect by ΔclpXP mutation on the production of flagellar proteins, suggesting that the ClpXP possibly defines a regulatory pathway affecting the expression of flagellar regulon that is dependent on FlhD/FlhC master regulators.

scholarly journals Evidence for a Chromosomally Located Third Integron in Salmonella enterica Serovar Typhimurium DT104b

2004 ◽  
Vol 48 (4) ◽  
pp. 1350-1352 ◽  
Author(s):  
M. Daly ◽  
J. Buckley ◽  
E. Power ◽  
S. Fanning
Keyword(s):  
Antimicrobial Resistance ◽  
Genetic Mapping ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Bacterial Chromosome ◽  
Class 1 Integron ◽  
Phage Types ◽  
Serovar Typhimurium ◽  
Class 1

ABSTRACT Salmonella enterica serovar Typhimurium isolates of phage types DT104 and DT104b are frequently associated with multiple antimicrobial resistance. We describe the characterization of a class 1 integron containing dfrA1 and aadA1, genes from two Salmonella serovar Typhimurium DT104b isolates. Genetic mapping located the integron to the bacterial chromosome in each case.

scholarly journals The Transcript from the σ28-Dependent Promoter Is Translationally Inert in the Expression of the σ28-Encoding GenefliAin thefliAZOperon of Salmonella enterica Serovar Typhimurium

2011 ◽  
Vol 193 (22) ◽  
pp. 6132-6141 ◽  
Author(s):  
Yasushi Tanabe ◽  
Takeo Wada ◽  
Katsuhiko Ono ◽  
Tatsuhiko Abo ◽  
Kazuhiro Kutsukake
Keyword(s):  
Rna Polymerase ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory Region ◽  
Content Type ◽  
Ribosome Binding ◽  
Serovar Typhimurium ◽  
Shine Dalgarno Sequence

There are three classes of promoters for flagellar operons inSalmonella. Class 2 promoters are transcribed by σ70RNA polymerase in the presence of an essential activator, FlhD4C2, and activated by an auxiliary regulator, FliZ. Class 3 promoters are transcribed by σ28RNA polymerase and repressed by an anti-σ28factor, FlgM. σ28(FliA) and FliZ are encoded by thefliAandfliZgenes, respectively, which together constitute an operon transcribed in this order. This operon is transcribed from both class 2 and class 3 promoters, suggesting that it should be activated by its own product, σ28, even in the absence of FlhD4C2. However, σ28-dependent transcription occursin vivoonly in the presence of FlhD4C2, indicating that transcription from the class 2 promoter is a prerequisite to that from the class 3 promoter. In this study, we examined the effects of variously modified versions of thefliAregulatory region on transcription and translation of thefliAgene. We showed that FliA is not significantly translated from the class 3 transcript. In contrast, the 5′-terminal AU-rich sequence found in the class 2 transcript confers efficientfliAtranslation. Replacement of the Shine-Dalgarno sequence of thefliAgene with a better one improvedfliAtranslation from the class 3 transcript. These results suggest that the 5′-terminal AU-rich sequence of the class 2 transcript may assist ribosome binding. FliZ was shown to be expressed from both the class 2 and class 3 transcripts.

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