MUTANTS OF<i>STAPHYLOCOCCUS AUREUS</i>AFFECTED IN THE REGULATION OF EXOPROTEIN SYNTHESIS

Björklind, Anders; Arvidson, Staffan

doi:10.1111/j.1574-6941.1980.tb01626.x

Cited by 88 publications

(61 citation statements)

References 13 publications

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“…The production of staphylococcal exoproteins is regulated in a coordinated growth phase-dependent manner, occurring preferentially during post-exponential phase of growth (4,31). In this study, the exoproteins of NCTC832S were analyzed by 2-DE at the late-log, earlystationary and late-stationary phases of growth (Fig.…”

Section: -De Analysis Of Exoproteins At Various Stages Of the Culturementioning

confidence: 99%

Proteolytic Cleavage of Staphylococcal Exoproteins Analyzed by Two‐Dimensional Gel Electrophoresis

Kawano

Kawagishi

Nakano

et al. 2001

Microbiology and Immunology

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Extracellular proteases of Staphylococcus aureus are emerging as potential virulence factors that are relevant to the pathogenicity of staphylococcal infections. These proteases may also be involved in the proteolytic cleavage of other exoproteins released from this organism. To define the target exoproteins and their sites of cleavage by proteases, high-resolution two-dimensional polyacrylamide gel electrophoresis followed by N-terminal amino acid sequencing of exoprotein spots was performed. Two to three hundred exoprotein spots were detected at the early-stationary phase of cultures of S. aureus NCTC8325, and then at the late-stationary stage most of these high molecular protein spots became invisible due to further proteolytic degradation. As the result of N-terminal analysis, lipase, triacylglycerollipase, orf619 protein and orf388 protein were detected as multiple spots at the early-stationary phase. We found that these exoproteins were cleaved at 3, 7, 4 and 4 different sites, respectively, by proteases. According to the M.W. and pI of each peptide spot obtained from the gel and their matches with calculated values in addition to their Nterminal sequences, we showed that the positions of putative peptides resulted from proteolytic cleavage of these proteins. Key words: Staphylococcal exoproteins, Extracellular proteases, Two-dimensional polyacrylamide-gel electrophoresisStaphylococcus aureus is an important human pathogen implicated in a wide range of diseases including septicemia, meningitis, endocarditis, osteomyelitis, toxic-shock syndrome (TSS) and food poisoning (21,28,34). Incidences of both community-and hospitalacquired staphylococcal infections are increasing because of its rapid development of antibiotic resistance (29).S. aureus secretes a large number of extracellular proteins (exoproteins), which have been shown to contribute to the pathogenic activities or to enhance the virulence of this organism (15,21,25,33). Recently, renewed interest has focused on proteases secreted from S. aureus under the control of agr (accessory gene regulator) and sar (staphylococcal accessory regulator), the main regulators of S. aureus virulence determinant genes (6,7,12,24). The expression of a specific serine glutamyl endopeptidase, V8 protease, was found to be *Address correspondence to Dr. Michio Ohta, Department of Molecular Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan. Fax: + 81-52-744-2107. E-mail: mohta @med.nagoya-u.ac.jp 285 important for virulence in animal models of staphylococcal infections (8). In addition to V8 protease, S. au reus secretes at least two other proteases, staphopain (papain-like thiol protease) (2) and aureolysin (typical metalloproteinase) (I). These proteases also encompass enzymes including Pseudomonas aeruginosa elastase (23), Legionella pneumophila (18) and Listeria monocytogenes metalloproteinases (9), Vibrio cholerae hemagglutinin protease (5), Staphylococcus epidermidis elastase (32), and the ...

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Section: -De Analysis Of Exoproteins At Various Stages Of the Culturementioning

confidence: 99%

Proteolytic Cleavage of Staphylococcal Exoproteins Analyzed by Two‐Dimensional Gel Electrophoresis

Kawano

Kawagishi

Nakano

et al. 2001

Microbiology and Immunology

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“…In S. aureus, spontaneous pleiotropic mutations affecting postexponential-phase exoprotein production (Exp mutations) have been described by several laboratories (5,47); commonly, these mutations block the synthesis of the following proteins: serine protease, nuclease, metalloproteinase, staphylokinase, acid phosphatase, a-, P-, and 8-hemolysin, enterotoxin B, and toxic shock syndrome toxin 1, whereas production of protein A and coagulase is increased (5,24,40). One such pleiotropic exoprotein-deficient mutation was the result of a TnS51 insertion in a regulatory element designated agr (26,37,40).…”

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A temporal signal, independent of agr, is required for hla but not spa transcription in Staphylococcus aureus

Vandenesch¹,

Kornblum²,

Novick³

1991

J Bacteriol

167

155

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Staphylococcus aureus exoprotein expression is controlled by a global regulon known as agr. This system activates transcription of some target genes and represses transcription of others. Target genes expressed postexponentially such as a-hemolysin (hla) are activated by agr; target genes expressed during exponential phase such as protein A (spa) are repressed by agr. A unique feature of the agr system is that this transcriptional regulation is mediated by a 517-nucleotide transcript, RNAIII. While it is clear that agr differentially regulates the expression of exponential and postexponential exoproteins, the precise role of agr in the temporal control of these events has not yet been explored. In this report, we examine the effects of expressing RNAIII, the agr regulator, under the control of the inducible ,B-lactamase (bla) promoter at different times in the growth cycle. We confirm previous results showing that agr is required for postexponential-phase expression of hla and further show that a separate postexponential-phase signal independent of agr function is also needed for activation of hla transcription. We also show that in an agr mutant transcription of spa occurs throughout the growth cycle, is inhibited immediately upon induction of RNAIII, and is thus indifferent to the postexponential signal required for hia activation.

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“…sec expression was reduced at alkaline pH in strain FRI1230 (Agr+) but not in its Agr-derivative, indicating that an intact agr allele is required for the pH effect on sec. Examination of batch cultures under conditions of nonmaintained pH gave results that were also consistent with a role for alkaline pH in repressing agr expression.The Staphylococcus aureus accessory gene regulator (agr) was identified initially as a locus which, when inactivated, results in altered production of several exoproteins and cell surface-associated proteins (7,25). An Agr+ strain produces more ax-hemolysin, ,-hemolysin, toxic shock syndrome toxin 1 (TSST-1), and staphylococcal enterotoxin types B, C, and D (SEB, SEC, and SED, respectively) and less coagulase and protein A (2,3,12,13,25,27) than its Agrderivative.…”

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Alkaline pH decreases expression of the accessory gene regulator (agr) in Staphylococcus aureus

1992

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The effect of alkaline pH on expression of the accessory gene regulator (agr) in Staphylococcus aureus was examined. agr, a global regulator, affects the expression of numerous exoproteins, including a-hemolysin, toxic shock syndrome toxin 1, protein A, and staphylococcal enterotoxins types B, C, and D. agr contains two major, divergent transcripts, designated RNAII and RNAHI. In this study, the level of RNAIII was used to monitor agr expression because this transcript and/or its protein product(s) appears to be responsible for altering target gene expression. S. aureus FRI1230 and its Agr-derivative were examined in a fermentor system which allowed batch cultures to be maintained at a constant pH. FRI1230 cultures were grown at pH 6.5, 7.0, 7.5, and 8.0. Northern (RNA blot) analysis of samples revealed that maximal agr expression occurred at pH 7.0, with virtually no RNAI observed at pH 8.0. The effect of alkaline pH on an agr target gene, sec, was also evaluated. sec expression was reduced at alkaline pH in strain FRI1230 (Agr+) but not in its Agr-derivative, indicating that an intact agr allele is required for the pH effect on sec. Examination of batch cultures under conditions of nonmaintained pH gave results that were also consistent with a role for alkaline pH in repressing agr expression.The Staphylococcus aureus accessory gene regulator (agr) was identified initially as a locus which, when inactivated, results in altered production of several exoproteins and cell surface-associated proteins (7,25). An Agr+ strain produces more ax-hemolysin, ,-hemolysin, toxic shock syndrome toxin 1 (TSST-1), and staphylococcal enterotoxin types B, C, and D (SEB, SEC, and SED, respectively) and less coagulase and protein A (2,3,12,13,25,27) than its Agrderivative. The ability of agr to function as both an activator and a repressor suggests the existence of two mechanisms for agr-mediated regulation.Nucleotide and mutational analysis of the agr locus revealed that it is a divergent operon containing two major transcripts that are referred to as RNAII and RNAIII (3.5 and 0.5 kb in length, respectively [1,15,16,20,23,24]).

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MUTANTS OFSTAPHYLOCOCCUS AUREUSAFFECTED IN THE REGULATION OF EXOPROTEIN SYNTHESIS

Cited by 88 publications

References 13 publications

Proteolytic Cleavage of Staphylococcal Exoproteins Analyzed by Two‐Dimensional Gel Electrophoresis

Proteolytic Cleavage of Staphylococcal Exoproteins Analyzed by Two‐Dimensional Gel Electrophoresis

A temporal signal, independent of agr, is required for hla but not spa transcription in Staphylococcus aureus

Alkaline pH decreases expression of the accessory gene regulator (agr) in Staphylococcus aureus

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