IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Blevins, J. S.
Right arrow Articles by Smeltzer, M. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Blevins, J. S.
Right arrow Articles by Smeltzer, M. S.
Infection and Immunity, February 2002, p. 470-480, Vol. 70, No. 2
0019-9567/01/$04.00+0     DOI: 10.1128/IAI.70.2.470-480.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Strain-Dependent Differences in the Regulatory Roles of sarA and agr in Staphylococcus aureus

Jon S. Blevins,1 Karen E. Beenken,1 Mohamed O. Elasri,1 Barry K. Hurlburt,2,3 and Mark S. Smeltzer1*

Departments of Microbiology and Immunology,1 Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205,2 U.S. Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 701243

Received 11 July 2001/ Returned for modification 10 September 2001/ Accepted 22 October 2001

The accessory gene regulator (agr) and the staphylococcal accessory regulator (sar) are central regulatory elements that control the production of Staphylococcus aureus virulence factors. To date, the functions of these loci have been defined almost exclusively using RN6390, which is representative of the laboratory strain 8325-4. However, RN6390 was recently shown to have a mutation in rsbU that results in a phenotype resembling that of a sigB mutant (I. Kullik et al., J. Bacteriol. 180:4814–4820, 1998). For that reason, it remains unclear whether the regulatory events defined in RN6390 are representative of the events that take place in clinical isolates of S. aureus. To address this issue, we generated mutations in the sarA and agr loci of three laboratory strains (RN6390, Newman, and S6C) and four clinical isolates (UAMS-1, UAMS-601, DB, and SC-1). Mutation of sarA in the cna-positive strains UAMS-1 and UAMS-601 resulted in an increased capacity to bind collagen, while mutation of agr had little impact. Northern blot analysis confirmed that the increase in collagen binding was due to increased cna transcription. Without exception, mutation of sarA resulted in increased production of proteases and a decreased capacity to bind fibronectin. Mutation of agr had the opposite effect. Although mutation of sarA resulted in a slight reduction in fnbA transcription, changes in the ability to bind fibronectin appeared to be more directly correlated with changes in protease activity. Lipase production was reduced in both sarA and agr mutants. While mutation of sarA in RN6390 resulted in reduced hemolytic activity, it had the opposite effect in all other strains. There appeared to be reduced levels of the sarC transcript in RN6390, but there was no difference in the overall pattern of sar transcription or the production of SarA. Although mutation of sarA resulted in decreased RNAIII transcription, this effect was not evident under all growth conditions. Taken together, these results suggest that studies defining the regulatory roles of sarA and agr by using RN6390 are not always representative of the events that occur in clinical isolates of S. aureus.

* Corresponding author. Mailing address: Department of Microbiology and Immunology, Mail Slot 511, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR 72205. Phone: (501) 686-7958. Fax: (501) 686-5359. E-mail: smeltzermarks{at}uams.edu.

Editor: E. I. Tuomanen

Infection and Immunity, February 2002, p. 470-480, Vol. 70, No. 2
0019-9567/01/$04.00+0     DOI: 10.1128/IAI.70.2.470-480.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2002 by the American Society for Microbiology. All rights reserved.