Abstract

Most patients with the genetic disease cystic fibrosis (CF) become colonized and infected with mucoid strains of Pseudomonas aeruginosa. These strains are mucoid due to the overproduction of a polysaccharide called alginate, which plays a role in the pathogenesis of P. aeruginosa in the lungs of CF patients. This viscous polymer impairs lung function and makes it almost impossible to eradicate the organism from the CF respiratory tract, making P. aeruginosa infections the major cause of death in CF patients. Therefore, the long-term objective of this proposal is to understand the molecular basis for the overproduction of alginate by strains of P. aeruginosa which infect cystic fibrosis patients. The alginate biosynthetic genes are controlled by a complex, multigenic regulatory network. The research proposed here will focus on the role of a AlgB, a key alginate regulatory protein, in the control of alginate biosynthesis. In order to understand this, two critical questions which constitute the aims of this proposal will be addressed. The first goal is to identify the molecular targets of AlgB. This will be accomplished by DNA binding studies, a deletion analysis of algD, genetic characterization of algB suppressor strains, and the use of transcriptional fusions to isolate genes under AlgB control. Another aim of this proposal is to determine the mechanism of algB transcriptional activation. In particular, the roles of the alginate regulator AlgT and the DNA binding/bending protein integration host factor in algB expression will be investigated. The algB promoter(s) responsive to these proteins will be characterized by ribonuclease protection mapping and primerextension analysis. The combination of biochemical and genetic approaches utilized in these studies should provide insights into the complex regulation of this important virulence factor with the ultimate goal of an improved quality of lite for CF patients colonized with alginate-producing strains of P. aeruginosa.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29AI035177-02
Application #
2070638
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1994-09-01
Project End
1999-08-31
Budget Start
1995-09-01
Budget End
1996-08-31
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost

  Institution

Name
Wake Forest University Health Sciences
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
041418799
City
Winston-Salem
State
NC
Country
United States
Zip Code
27106

  Publications

Huigens 3rd, Robert W; Ma, Luyan; Gambino, Christopher et al. (2008) Control of bacterial biofilms with marine alkaloid derivatives. Mol Biosyst 4:614-21
Baynham, Patricia J; Ramsey, Deborah M; Gvozdyev, Borys V et al. (2006) The Pseudomonas aeruginosa ribbon-helix-helix DNA-binding protein AlgZ (AmrZ) controls twitching motility and biogenesis of type IV pili. J Bacteriol 188:132-40
Tart, Anne H; Wolfgang, Matthew C; Wozniak, Daniel J (2005) The alternative sigma factor AlgT represses Pseudomonas aeruginosa flagellum biosynthesis by inhibiting expression of fleQ. J Bacteriol 187:7955-62
Ramsey, Deborah M; Wozniak, Daniel J (2005) Understanding the control of Pseudomonas aeruginosa alginate synthesis and the prospects for management of chronic infections in cystic fibrosis. Mol Microbiol 56:309-22
Mishra, Meenu; Parise, Gina; Jackson, Kara D et al. (2005) The BvgAS signal transduction system regulates biofilm development in Bordetella. J Bacteriol 187:1474-84
Ramsey, Deborah M; Baynham, Patricia J; Wozniak, Daniel J (2005) Binding of Pseudomonas aeruginosa AlgZ to sites upstream of the algZ promoter leads to repression of transcription. J Bacteriol 187:4430-43
Jackson, Kara D; Starkey, Melissa; Kremer, Stefanie et al. (2004) Identification of psl, a locus encoding a potential exopolysaccharide that is essential for Pseudomonas aeruginosa PAO1 biofilm formation. J Bacteriol 186:4466-75
Cobb, Laura M; Mychaleckyj, Josyf C; Wozniak, Daniel J et al. (2004) Pseudomonas aeruginosa flagellin and alginate elicit very distinct gene expression patterns in airway epithelial cells: implications for cystic fibrosis disease. J Immunol 173:5659-70
Wozniak, Daniel J; Sprinkle, April B; Baynham, Patricia J (2003) Control of Pseudomonas aeruginosa algZ expression by the alternative sigma factor AlgT. J Bacteriol 185:7297-300
Wozniak, Daniel J; Wyckoff, Timna J O; Starkey, Melissa et al. (2003) Alginate is not a significant component of the extracellular polysaccharide matrix of PA14 and PAO1 Pseudomonas aeruginosa biofilms. Proc Natl Acad Sci U S A 100:7907-12

Showing the most recent 10 out of 21 publications