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Oligopeptide permease is required for expression of the Bacillus thuringiensis plcR regulon and for virulence.
Mol Microbiol 2001; 40(4):963-75MM

Abstract

PlcR is a pleiotropic regulator of virulence factors in the insect pathogen Bacillus thuringiensis and in the opportunistic human pathogen Bacillus cereus. It activates the transcription of at least 15 genes encoding extracellular proteins, including phospholipases C, proteases and enterotoxins. Expression of the plcR gene is autoregulated and activated at the onset of stationary phase. Here, we used mini-Tn10 transposition to generate a library of B. thuringiensis mutants, with the goal of characterizing genes involved in the expression of the plcR gene. Three mutant strains were identified carrying distinct mini-Tn10 insertions. The mutations impaired plcR expression and caused a deficient haemolytic phenotype, similar to the phenotype of a B. thuringiensis strain in which the plcR gene had been disrupted. The insertion sites of the three mini-Tn10 transposons mapped in a five-gene operon encoding polypeptides homologous to the components of the oligopeptide permease (Opp) system of Bacillus subtilis, and with a similar structural organization. By analogy, the five B. thuringiensis genes were designated oppA, B, C, D and F. In vitro disruption of the B. thuringiensis oppB gene reproduced the effect of the mini-Tn10 insertions (i.e. the loss of haemolytic activity) and reduced the virulence of the strain against insects. These phenotypes are similar to those of a DeltaplcR mutant. Opp is required for the import of small peptides into the cell. Therefore, plcR expression might be activated at the onset of stationary phase by the uptake of a signalling peptide acting as a quorum-sensing effector. The opp mutations impaired the sporulation efficiency of B. thuringiensis when the cells were cultured in LB medium. Thus, Opp is on the pathway that ultimately regulates Spo0A phosphorylation, as is the case in B. subtilis. However, analysis of plcR expression in DeltaoppB, Deltaspo0A and DeltaoppB Deltaspo0A mutants indicates that Opp is required for plcR expression via a Spo0A-independent mechanism.

Authors+Show Affiliations

Unité de Biochimie Microbienne, CNRS (URA2172), Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris cedex, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11401703

Citation

Gominet, M, et al. "Oligopeptide Permease Is Required for Expression of the Bacillus Thuringiensis plcR Regulon and for Virulence." Molecular Microbiology, vol. 40, no. 4, 2001, pp. 963-75.
Gominet M, Slamti L, Gilois N, et al. Oligopeptide permease is required for expression of the Bacillus thuringiensis plcR regulon and for virulence. Mol Microbiol. 2001;40(4):963-75.
Gominet, M., Slamti, L., Gilois, N., Rose, M., & Lereclus, D. (2001). Oligopeptide permease is required for expression of the Bacillus thuringiensis plcR regulon and for virulence. Molecular Microbiology, 40(4), pp. 963-75.
Gominet M, et al. Oligopeptide Permease Is Required for Expression of the Bacillus Thuringiensis plcR Regulon and for Virulence. Mol Microbiol. 2001;40(4):963-75. PubMed PMID: 11401703.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oligopeptide permease is required for expression of the Bacillus thuringiensis plcR regulon and for virulence. AU - Gominet,M, AU - Slamti,L, AU - Gilois,N, AU - Rose,M, AU - Lereclus,D, PY - 2001/6/13/pubmed PY - 2001/8/10/medline PY - 2001/6/13/entrez SP - 963 EP - 75 JF - Molecular microbiology JO - Mol. Microbiol. VL - 40 IS - 4 N2 - PlcR is a pleiotropic regulator of virulence factors in the insect pathogen Bacillus thuringiensis and in the opportunistic human pathogen Bacillus cereus. It activates the transcription of at least 15 genes encoding extracellular proteins, including phospholipases C, proteases and enterotoxins. Expression of the plcR gene is autoregulated and activated at the onset of stationary phase. Here, we used mini-Tn10 transposition to generate a library of B. thuringiensis mutants, with the goal of characterizing genes involved in the expression of the plcR gene. Three mutant strains were identified carrying distinct mini-Tn10 insertions. The mutations impaired plcR expression and caused a deficient haemolytic phenotype, similar to the phenotype of a B. thuringiensis strain in which the plcR gene had been disrupted. The insertion sites of the three mini-Tn10 transposons mapped in a five-gene operon encoding polypeptides homologous to the components of the oligopeptide permease (Opp) system of Bacillus subtilis, and with a similar structural organization. By analogy, the five B. thuringiensis genes were designated oppA, B, C, D and F. In vitro disruption of the B. thuringiensis oppB gene reproduced the effect of the mini-Tn10 insertions (i.e. the loss of haemolytic activity) and reduced the virulence of the strain against insects. These phenotypes are similar to those of a DeltaplcR mutant. Opp is required for the import of small peptides into the cell. Therefore, plcR expression might be activated at the onset of stationary phase by the uptake of a signalling peptide acting as a quorum-sensing effector. The opp mutations impaired the sporulation efficiency of B. thuringiensis when the cells were cultured in LB medium. Thus, Opp is on the pathway that ultimately regulates Spo0A phosphorylation, as is the case in B. subtilis. However, analysis of plcR expression in DeltaoppB, Deltaspo0A and DeltaoppB Deltaspo0A mutants indicates that Opp is required for plcR expression via a Spo0A-independent mechanism. SN - 0950-382X UR - https://www.unboundmedicine.com/medline/citation/11401703/Oligopeptide_permease_is_required_for_expression_of_the_Bacillus_thuringiensis_plcR_regulon_and_for_virulence_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0950-382X&date=2001&volume=40&issue=4&spage=963 DB - PRIME DP - Unbound Medicine ER -