scholarly journals Ribosomal Protein S1 Specifically Binds to the 5′ Untranslated Region of the Pseudomonas aeruginosa Stationary-Phase Sigma Factor rpoS mRNA in the Logarithmic Phase of Growth

2004 ◽  
Vol 186 (15) ◽  
pp. 4903-4909 ◽  
Author(s):  
Milica Ševo ◽  
Emanuele Buratti ◽  
Vittorio Venturi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Ribosomal Protein ◽  
Sigma Factor ◽  
Untranslated Region ◽  
Stationary Phases ◽  
Translation Regulation ◽  
Logarithmic Phase ◽  
Ribosomal Protein S1 ◽  
Sigma Factor Rpos

ABSTRACT The rpoS gene encodes the stationary-phase sigma factor (RpoS or σs), which was identified in several gram-negative bacteria as a central regulator controlling the expression of genes involved in cell survival in response to cessation of growth (stationary phase) and providing cross-protection against various stresses. In Pseudomonas aeruginosa, the levels of σs increase dramatically at the onset of the stationary phase and are regulated at the transcriptional and posttranscriptional levels. The P. aeruginosa rpoS gene is transcribed as a monocistronic rpoS mRNA transcript comprised of an unusually long 373-bp 5′ untranslated region (5′ UTR). In this study, the 5′ UTR and total protein extracts from P. aeruginosa logarithmic and stationary phases of growth were used in order to investigate the protein-RNA interactions that may modulate the translational process. It was observed that a 69-kDa protein, which corresponded to ribosomal protein S1, preferentially binds the 5′ UTR of the rpoS mRNA in the logarithmic phase and not in the stationary phase. This is the first report of a protein-rpoS mRNA 5′ UTR interaction in P. aeruginosa, and the possible involvement of protein S1 in translation regulation of rpoS is discussed.

scholarly journals Characterization of a Stress-Induced Alternate Sigma Factor, RpoS, of Coxiella burnetii and Its Expression during the Development Cycle

2001 ◽  
Vol 69 (8) ◽  
pp. 4874-4883 ◽  
Author(s):  
Rekha Seshadri ◽  
James E. Samuel
Keyword(s):  
Stationary Phase ◽  
Coxiella Burnetii ◽  
Sigma Factor ◽  
Stationary Phases ◽  
Large Cell ◽  
Polyclonal Antiserum ◽  
Developmental Cycle ◽  
Growth Stages ◽  
Extracellular Environment ◽  
Sigma Factor Rpos

ABSTRACT Coxiella burnetii is an obligate intracellular bacterium that resides in an acidified phagolysosome and has a remarkable ability to persist in the extracellular environment.C. burnetii has evolved a developmental cycle that includes at least two morphologic forms, designated large cell variants (LCV) and small cell variants (SCV). Based on differential protein expression, distinct ultrastructures, and different metabolic activities, we speculated that LCV and SCV are similar to typical logarithmic- and stationary-phase growth stages. We hypothesized that the alternate sigma factor, RpoS, a global regulator of genes expressed under stationary-phase, starvation, and stress conditions in many bacteria, regulates differential expression in life cycle variants of C. burnetii. To test this hypothesis, we cloned and characterized the major sigma factor, encoded by an rpoD homologue, and the stress response sigma factor, encoded by an rpoS homologue. TherpoS gene was cloned by complementation of anEscherichia coli rpoS null mutant containing an RpoS-dependent lacZ fusion (osmY::lacZ). Expression ofC. burnetii rpoS was regulated by growth phase inE. coli (induced upon entry into stationary phase). A glutathione S-transferase–RpoS fusion protein was used to develop polyclonal antiserum against C. burnetii RpoS. Western blot analysis detected abundant RpoS in LCV but not in SCV. These results suggest that LCV and SCV are not comparable to logarithmic and stationary phases of growth and may represent a novel adaptation for survival in both the phagolysosome and the extracellular environment.

scholarly journals Pseudomonas aeruginosaBiofilm Antibiotic Resistance GenendvBExpression Requires the RpoS Stationary-Phase Sigma Factor

2018 ◽  
Vol 84 (7) ◽  
Author(s):  
Clayton W. Hall ◽  
Aaron J. Hinz ◽  
Luke B.-P. Gagnon ◽  
Li Zhang ◽  
Jean-Paul Nadeau ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Stationary Phase ◽  
Sigma Factor ◽  
Fluorescent Protein ◽  
Opportunistic Pathogen ◽  
Planktonic Cells ◽  
Content Type ◽  
Green Fluorescent ◽  
Sigma Factor Rpos

ABSTRACTChronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogenPseudomonas aeruginosa, biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential-phase planktonic cells. One such mechanism involvesndvB, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable green fluorescent protein (GFP) transcriptional reporter to observe the expression pattern ofndvB. We found that in addition to its expression in biofilms,ndvBwas upregulated in planktonic cells as they enter stationary phase. The transcription ofndvBin both growth phases was shown to be dependent on the stationary-phase sigma factor RpoS, and mutation of a putative RpoS binding site in thendvBpromoter abolished the activity of the promoter in stationary-phase cells. Overall, we have expanded our understanding of the temporal expression ofndvBinP. aeruginosaand have uncovered a regulatory basis for its growth phase-dependent expression.IMPORTANCEBacterial biofilms are more resistant to antibiotics than free-living planktonic cells, and understanding the mechanistic basis of this resistance can inform treatments of biofilm-based infections. In addition to chemical and structural barriers that can inhibit antibiotic entry, the upregulation of specific genes in biofilms contributes to the resistance. We investigated this biofilm-specific gene induction by examining expression patterns ofndvB, a gene involved in biofilm resistance of the opportunistic pathogenPseudomonas aeruginosa. We characterizedndvBexpression in planktonic and biofilm growth conditions with an unstable green fluorescent protein (GFP) reporter and found that the expression ofndvBin biofilms is dependent on the stationary-phase sigma factor RpoS. Overall, our results support the physiological similarity between biofilms and stationary-phase cells and suggest that the induction of some stationary-phase genes in biofilms may contribute to their increased antibiotic resistance.

scholarly journals Gene expression and protein levels of the stationary phase sigma factor, RpoS, in continuously-fed Pseudomonas aeruginosa biofilms

2001 ◽  
Vol 199 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Karen D. Xu ◽  
Michael J. Franklin ◽  
Chul-Ho Park ◽  
Gordon A. McFeters ◽  
Philip S. Stewart
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Sigma Factor ◽  
Protein Levels ◽  
Sigma Factor Rpos

scholarly journals An A/U-Rich Enhancer Region Is Required for High-Level Protein Secretion through the HlyA Type I Secretion System

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Sakshi Khosa ◽  
Romy Scholz ◽  
Christian Schwarz ◽  
Mirko Trilling ◽  
Hartmut Hengel ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Protein Secretion ◽  
Fusion Proteins ◽  
Untranslated Region ◽  
Secretion System ◽  
Type I ◽  
Secretion Systems ◽  
Enhancer Region ◽  
Ribosomal Protein S1 ◽  
Cellular Expression

ABSTRACTEfficient protein secretion is often a valuable alternative to classic cellular expression to obtain homogenous protein samples. Early on, bacterial type I secretion systems (T1SS) were employed to allow heterologous secretion of fusion proteins. However, this approach was not fully exploited, as many proteins could not be secreted at all or only at low levels. Here, we present an engineered microbial secretion system which allows the effective production of proteins up to a molecular mass of 88 kDa. This system is based on the hemolysin A (HlyA) T1SS of the Gram-negative bacteriumEscherichia coli, which exports polypeptides when fused to a hemolysin secretion signal. We identified an A/U-rich enhancer region upstream ofhlyArequired for effective expression and secretion of selected heterologous proteins irrespective of their prokaryotic, viral, or eukaryotic origin. We further demonstrate that the ribosomal protein S1 binds to thehlyAA/U-rich enhancer region and that this region is involved in the high yields of secretion of functional proteins, like maltose-binding protein or human interferon alpha-2.IMPORTANCEA 5′ untranslated region of the mRNA of substrates of type I secretion systems (T1SS) drastically enhanced the secretion efficiency of the endogenously secreted protein. The identification of ribosomal protein S1 as the interaction partner of this 5′ untranslated region provides a rationale for the enhancement. This strategy furthermore can be transferred to fusion proteins allowing a broader, and eventually a more general, application of this system for secreting heterologous fusion proteins.

scholarly journals Variation of Physiochemical Properties and Cell Association Activity of Membrane Vesicles with Growth Phase in Pseudomonas aeruginosa

2010 ◽  
Vol 76 (11) ◽  
pp. 3732-3739 ◽  
Author(s):  
Yosuke Tashiro ◽  
Sosaku Ichikawa ◽  
Motoyuki Shimizu ◽  
Masanori Toyofuku ◽  
Naoki Takaya ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Stationary Phases ◽  
Membrane Vesicles ◽  
Exponential Phase ◽  
Phase Changes ◽  
Bacterial Cells ◽  
Physiochemical Properties ◽  
Cell Association ◽  
Phase Surface

ABSTRACT Pseudomonas aeruginosa and other Gram-negative bacteria release membrane vesicles (MVs) from their surfaces, and MVs have an ability to interact with bacterial cells. Although it has been known that many bacteria have mechanisms that control their phenotypes with the transition from exponential phase to stationary phase, changes of properties in released MVs have been poorly understood. Here, we demonstrate that MVs released by P. aeruginosa during the exponential and stationary phases possess different physiochemical properties. MVs purified from the stationary phase had higher buoyant densities than did those purified from the exponential phase. Surface charge, characterized by zeta potential, of MVs tended to be more negative as the growth shifted to the stationary phase, although the charges of PAO1 cells were not altered. Pseudomonas quinolone signal (PQS), one of the regulators related to MV production in P. aeruginosa, was lower in MVs purified from the exponential phase than in those from the stationary phase. MVs from the stationary phase more strongly associated with P. aeruginosa cells than did those from the exponential phase. Our findings suggest that properties of MVs are altered to readily interact with bacterial cells along with the growth transition in P. aeruginosa.

scholarly journals Different Spectra of Stationary-Phase Mutations in Early-Arising versus Late-Arising Mutants of Pseudomonas putida: Involvement of the DNA Repair Enzyme MutY and the Stationary-Phase Sigma Factor RpoS

2002 ◽  
Vol 184 (24) ◽  
pp. 6957-6965 ◽  
Author(s):  
Signe Saumaa ◽  
Andres Tover ◽  
Lagle Kasak ◽  
Maia Kivisaar
Keyword(s):  
Stationary Phase ◽  
Pseudomonas Putida ◽  
Transcriptional Activation ◽  
Sigma Factor ◽  
Phenol Degradation ◽  
Test System ◽  
Growth Barriers ◽  
Mutational Processes ◽  
Sigma Factor Rpos ◽  
Selection Of

ABSTRACT Stationary-phase mutations occur in populations of stressed, nongrowing, and slowly growing cells and allow mutant bacteria to overcome growth barriers. Mutational processes in starving cells are different from those occurring in growing bacteria. Here, we present evidence that changes in mutational processes also take place during starvation of bacteria. Our test system for selection of mutants based on creation of functional promoters for the transcriptional activation of the phenol degradation genes pheBA in starving Pseudomonas putida enables us to study base substitutions (C-to-A or G-to-T transversions), deletions, and insertions. We observed changes in the spectrum of promoter-creating mutations during prolonged starvation of Pseudomonas putida on phenol minimal plates. One particular C-to-A transversion was the prevailing mutation in starving cells. However, with increasing time of starvation, the importance of this mutation decreased but the percentage of other types of mutations, such as 2- to 3-bp deletions, increased. The rate of transversions was markedly elevated in the P. putida MutY-defective strain. The occurrence of 2- to 3-bp deletions required the stationary-phase sigma factor RpoS, which indicates that some mutagenic pathway is positively controlled by RpoS in P. putida.

Sign in / Sign up

Export Citation Format

Share Document