Tags

Type your tag names separated by a space and hit enter

Central regulatory role for the RpoS sigma factor in expression of Salmonella dublin plasmid virulence genes.
J Bacteriol. 1995 Sep; 177(18):5303-9.JB

Abstract

The plasmid virulence genes spvABCD of Salmonella spp. are regulated by SpvR and the stationary-phase sigma factor RpoS. The transcription of spv genes is induced during the post-exponential phase of bacterial growth in vitro. We sought to investigate the relationship between growth phase and RpoS in spv regulation. rpoS insertion mutations were constructed in S. dublin Lane and plasmid-cured LD842 strains, and the mutants were found to be attenuated for virulence and deficient in spv gene expression. We utilized the plasmid pBAD::rpoS to express rpoS independent of the growth phase under the control of the arabinose-inducible araBAD promoter. SpvA expression was induced within 2 h after the addition of 0.1% arabinose, even when bacteria were actively growing. This suggested that the level of RpoS, instead of the growth phase itself, controls induction of the spv genes. However, RpoS did not activate transcription of spvA in the absence of SpvR protein. Using a constitutive tet promoter to express spvR, we found that the spvA gene can be partially expressed in the rpoS mutant, suggesting that RpoS is required for SpvR synthesis. We confirmed that spvR is poorly expressed in the absence of RpoS. With an intact rpoS gene, spvR expression is not dependent on an intact spvR gene but is enhanced by spvR supplied in trans. We propose a model for Salmonella spv gene regulation in which both RpoS and SpvR are required for maximal expression at the spvR and spvA promoters.

Authors+Show Affiliations

Department of Medicine, School of Medicine, University of California at San Diego, La Jolla 92093-0640, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

7665519

Citation

Chen, C Y., et al. "Central Regulatory Role for the RpoS Sigma Factor in Expression of Salmonella Dublin Plasmid Virulence Genes." Journal of Bacteriology, vol. 177, no. 18, 1995, pp. 5303-9.
Chen CY, Buchmeier NA, Libby S, et al. Central regulatory role for the RpoS sigma factor in expression of Salmonella dublin plasmid virulence genes. J Bacteriol. 1995;177(18):5303-9.
Chen, C. Y., Buchmeier, N. A., Libby, S., Fang, F. C., Krause, M., & Guiney, D. G. (1995). Central regulatory role for the RpoS sigma factor in expression of Salmonella dublin plasmid virulence genes. Journal of Bacteriology, 177(18), 5303-9.
Chen CY, et al. Central Regulatory Role for the RpoS Sigma Factor in Expression of Salmonella Dublin Plasmid Virulence Genes. J Bacteriol. 1995;177(18):5303-9. PubMed PMID: 7665519.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Central regulatory role for the RpoS sigma factor in expression of Salmonella dublin plasmid virulence genes. AU - Chen,C Y, AU - Buchmeier,N A, AU - Libby,S, AU - Fang,F C, AU - Krause,M, AU - Guiney,D G, PY - 1995/9/1/pubmed PY - 1995/9/1/medline PY - 1995/9/1/entrez SP - 5303 EP - 9 JF - Journal of bacteriology JO - J Bacteriol VL - 177 IS - 18 N2 - The plasmid virulence genes spvABCD of Salmonella spp. are regulated by SpvR and the stationary-phase sigma factor RpoS. The transcription of spv genes is induced during the post-exponential phase of bacterial growth in vitro. We sought to investigate the relationship between growth phase and RpoS in spv regulation. rpoS insertion mutations were constructed in S. dublin Lane and plasmid-cured LD842 strains, and the mutants were found to be attenuated for virulence and deficient in spv gene expression. We utilized the plasmid pBAD::rpoS to express rpoS independent of the growth phase under the control of the arabinose-inducible araBAD promoter. SpvA expression was induced within 2 h after the addition of 0.1% arabinose, even when bacteria were actively growing. This suggested that the level of RpoS, instead of the growth phase itself, controls induction of the spv genes. However, RpoS did not activate transcription of spvA in the absence of SpvR protein. Using a constitutive tet promoter to express spvR, we found that the spvA gene can be partially expressed in the rpoS mutant, suggesting that RpoS is required for SpvR synthesis. We confirmed that spvR is poorly expressed in the absence of RpoS. With an intact rpoS gene, spvR expression is not dependent on an intact spvR gene but is enhanced by spvR supplied in trans. We propose a model for Salmonella spv gene regulation in which both RpoS and SpvR are required for maximal expression at the spvR and spvA promoters. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/7665519/Central_regulatory_role_for_the_RpoS_sigma_factor_in_expression_of_Salmonella_dublin_plasmid_virulence_genes_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=7665519 DB - PRIME DP - Unbound Medicine ER -