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Effects of DksA and ClpP protease on sigma S production and virulence in Salmonella typhimurium.
Mol Microbiol. 1999 Oct; 34(1):112-23.MM

Abstract

Salmonella typhimurium responds to a variety of environmental stresses by accumulating the alternative sigma factor sigmaS. The repertoire of sigmaS -dependent genes that are subsequently expressed confers tolerance to a variety of potentially lethal conditions including low pH and stationary phase. The mechanism(s) responsible for triggering sigmaS accumulation are of considerable interest, because they help to ensure survival of the organism during encounters with suboptimal environments. Two genes associated with regulating sigmaS levels in S. typhimurium have been identified. The first is clpP, encoding the protease known to be responsible for degrading sigmaS in Escherichia coli. The second is dksA, encoding a protein of unknown function not previously associated with regulating sigmaS levels. As predicted, clpP mutants accumulated large amounts of sigmaS even in log phase. However, dksA mutants failed to accumulate sigmaS in stationary phase and exhibited lower accumulation during acid shock in log phase. DksA appears to be required for the optimal translation of rpoS based upon dksA mutant effects on rpoS transcriptional and translational lacZ fusions. The region of rpoS mRNA between codons 8 and 73 is required to see the effects of dksA mutations. This distinguishes the role of DksA from that of HF-I (hfq) in rpoS translation, as the HF-I target area occurs well upstream of the rpoS start codon. DksA appears to be involved in the expression of several genes in addition to rpoS based on two-dimensional SDS-PAGE analysis of whole-cell proteins. As a result of their effects on gene expression, mutations in clpP and dksA decreased the virulence of S. typhimurium in mice, consistent with a role for sigmaS in pathogenesis.

Authors+Show Affiliations

Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, AL, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10540290

Citation

Webb, C, et al. "Effects of DksA and ClpP Protease On Sigma S Production and Virulence in Salmonella Typhimurium." Molecular Microbiology, vol. 34, no. 1, 1999, pp. 112-23.
Webb C, Moreno M, Wilmes-Riesenberg M, et al. Effects of DksA and ClpP protease on sigma S production and virulence in Salmonella typhimurium. Mol Microbiol. 1999;34(1):112-23.
Webb, C., Moreno, M., Wilmes-Riesenberg, M., Curtiss, R., & Foster, J. W. (1999). Effects of DksA and ClpP protease on sigma S production and virulence in Salmonella typhimurium. Molecular Microbiology, 34(1), 112-23.
Webb C, et al. Effects of DksA and ClpP Protease On Sigma S Production and Virulence in Salmonella Typhimurium. Mol Microbiol. 1999;34(1):112-23. PubMed PMID: 10540290.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of DksA and ClpP protease on sigma S production and virulence in Salmonella typhimurium. AU - Webb,C, AU - Moreno,M, AU - Wilmes-Riesenberg,M, AU - Curtiss,R,3rd AU - Foster,J W, PY - 1999/12/14/pubmed PY - 2001/3/28/medline PY - 1999/12/14/entrez SP - 112 EP - 23 JF - Molecular microbiology JO - Mol Microbiol VL - 34 IS - 1 N2 - Salmonella typhimurium responds to a variety of environmental stresses by accumulating the alternative sigma factor sigmaS. The repertoire of sigmaS -dependent genes that are subsequently expressed confers tolerance to a variety of potentially lethal conditions including low pH and stationary phase. The mechanism(s) responsible for triggering sigmaS accumulation are of considerable interest, because they help to ensure survival of the organism during encounters with suboptimal environments. Two genes associated with regulating sigmaS levels in S. typhimurium have been identified. The first is clpP, encoding the protease known to be responsible for degrading sigmaS in Escherichia coli. The second is dksA, encoding a protein of unknown function not previously associated with regulating sigmaS levels. As predicted, clpP mutants accumulated large amounts of sigmaS even in log phase. However, dksA mutants failed to accumulate sigmaS in stationary phase and exhibited lower accumulation during acid shock in log phase. DksA appears to be required for the optimal translation of rpoS based upon dksA mutant effects on rpoS transcriptional and translational lacZ fusions. The region of rpoS mRNA between codons 8 and 73 is required to see the effects of dksA mutations. This distinguishes the role of DksA from that of HF-I (hfq) in rpoS translation, as the HF-I target area occurs well upstream of the rpoS start codon. DksA appears to be involved in the expression of several genes in addition to rpoS based on two-dimensional SDS-PAGE analysis of whole-cell proteins. As a result of their effects on gene expression, mutations in clpP and dksA decreased the virulence of S. typhimurium in mice, consistent with a role for sigmaS in pathogenesis. SN - 0950-382X UR - https://www.unboundmedicine.com/medline/citation/10540290/Effects_of_DksA_and_ClpP_protease_on_sigma_S_production_and_virulence_in_Salmonella_typhimurium_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0950-382X&date=1999&volume=34&issue=1&spage=112 DB - PRIME DP - Unbound Medicine ER -