Exotoxin A and the siderophores (pyochelin and pyoverdine) are produced in P. aeruginosa by a complicated process that involves several genes. The long-term goal of this proposal is to define the mechanism that regulates the synthesis of exotoxin A and pyoverdine in P. aeruginosa and to identify the different factors that participate in this regulation. We have identified a gene, ptxR, which positively regulates the transcription of toxA, the toxA regulator regA, and the genes that code for some components of the pyoverdine system. Available evidence suggests that the regulation of these genes by ptxR is indirect (through an independent gene). In addition, the regulation of ptxR expression itself appears to involve several regulatory proteins, both identified and as yet unidentified. One identified protein, the alternative sigma factor PvdS, also regulates toxA and the pyoverdine genes. The unidentified proteins bind specifically to the ptxR upstream region.
The specific aims of this proposal are: 1) to determine the mechanism through which toxA and the pyoverdine genes are regulated by ptxR. This includes identification of the ptxR target sequence and the gene that carries it and characterization of the genes that are regulated (directly or indirectly) by ptxR; 2) to examine the regulation of ptxR expression in P. aeruginosa. This includes extensive in vivo and in vitro transcriptional analysis of the ptxR upstream region and examining ptxR expression in different specific P. aeruginosa mutants; and 3) to isolate and characterize the putative regulatory proteins and to identify the nucleotide sequences to which they bind.
These aims will be accomplished using protein purification experiments, simple and modified DNA/protein binding experiments, functional genomics, 2-D gel analysis, in vivo and in vitro transcription, and different recombinant DNA techniques.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI033386-07
Application #
6621010
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Taylor, Christopher E,
Project Start
1996-07-15
Project End
2007-02-28
Budget Start
2003-03-01
Budget End
2004-02-29
Support Year
7
Fiscal Year
2003
Total Cost
$222,000
Indirect Cost
Name
Texas Tech University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
609980727
City
Lubbock
State
TX
Country
United States
Zip Code
79430
Qaisar, Uzma; Luo, Liming; Haley, Cecily L et al. (2013) The pvc operon regulates the expression of the Pseudomonas aeruginosa fimbrial chaperone/usher pathway (cup) genes. PLoS One 8:e62735
Davinic, Marko; Carty, Nancy L; Colmer-Hamood, Jane A et al. (2009) Role of Vfr in regulating exotoxin A production by Pseudomonas aeruginosa. Microbiology 155:2265-73
Li, Wang; Lyte, Mark; Freestone, Primrose P et al. (2009) Norepinephrine represses the expression of toxA and the siderophore genes in Pseudomonas aeruginosa. FEMS Microbiol Lett 299:100-9
Westfall, Landon W; Carty, Nancy L; Layland, Nancy et al. (2006) mvaT mutation modifies the expression of the Pseudomonas aeruginosa multidrug efflux operon mexEF-oprN. FEMS Microbiol Lett 255:247-54