Enterococci are Gram-positive constituents of the human microflora and play beneficial roles in artisanal cheese production and as probiotics to treat gastroenteritis. Enterococci have emerged as one of the leading causes of nosocomial infections. The problem of enterococcal infection has been aggravated by the emergence of multiple antibiotic resistance that poses a serious challenge to therapeutic intervention. This is an issue of concern in medicine, to the scientific community and the general public. Direction in the search for new therapeutic approaches for treating enterococcal infections will come from a clearer understanding of the factors involved in the pathogenesis of the disease and their regulatory mechanisms. The availability of the E. faecalis genome sequence allowed us to identify the key components of the bacterial regulatory mechanisms carried out by two-component signal transduction systems. The research proposed in this application has the goal of defining the regulatory network of enterococcal signal transduction for the purpose of understanding the mechanisms underlying the physiology of these organisms. This will provide valuable information for the understanding of mechanisms responsible for pathogenicity and antibiotic resistance and thus the identification of molecular targets for therapeutic intervention. We have generated deletion mutants for all response regulators identified in E. faecalis V583. Phenotypes have been identified in some strains, and a role for the FsrA response regulator in controlling biofilm formation through regulation of gelatinase production has been revealed. We propose to: 1) determine the role of two-component systems in virulence through in vivo analyses; 2) determine the role of gelatinase in biofilm; 3) define the genes regulated by two-component signal transduction systems (the regulon) by transcriptional and proteomic approaches; 4) determine the role of the two-component systems in enterococcal physiology by turning ON or OFF the genes encoding response regulatory proteins and analyzing the resulting phenotypes. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI052289-04
Application #
7147444
Study Section
Special Emphasis Panel (ZRG1-BM-1 (01))
Program Officer
Peters, Kent
Project Start
2003-12-15
Project End
2008-11-30
Budget Start
2006-12-01
Budget End
2007-11-30
Support Year
4
Fiscal Year
2007
Total Cost
$400,441
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
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Hancock, Lynn E; Perego, Marta (2004) Systematic inactivation and phenotypic characterization of two-component signal transduction systems of Enterococcus faecalis V583. J Bacteriol 186:7951-8