Genes involved with Pseudomonas aeruginosa PA14 pathogenicity: characterization of promoter regions and virulence assays in Dictyostelium discoideum host model

• Grant number: 06/02163-0
• Support type: Scholarships in Brazil - Master
• Effective date (Start): September 01, 2006
• Effective date (End): August 31, 2008
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal researcher: Regina Lúcia Baldini
• Grantee: Ana Laura Boechat Borges
• Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Pseudomonas aeruginosa is an ubiquitous opportunistic Gram-negative bacterium that often infects immunocompromised individuals and is also responsible for nosocomial infections. Strain PA14 is able to infect several host models and the presence of pathogenicity islands may account for its high virulence. In the large pathogenicity island PAPI-1, two gene clusters transcribed in opposite directions are found: the first comprises two gene pairs, pvrSR e rcsCB that encode proteins of two-component systems and the second is a putative operon composed of five genes (cupD1-D5) encoding proteins similar to pili assembled via a chaperone-usher pathway. Mutant strains carrying deletions in pvrS, pvrR, rcsC or rcsB or with a transposon insertion in cupD2 are significantly attenuated in virulence. Data obtained from the literature, with either P. aeruginosa genes or with ortologues of these genes suggest that the two component systems present in PAPI-1 have a role in the regulation of expression of structures involved with the bacterium’s adhesion. cupD is highly similar to cupA, which has been shown to be required for biofilm formation in other strains of P. aeruginosa. Taken togheter, these data suggest that the two-component systems present in PAPI-1 may be involved in the regulation of cupD expression. Preliminary results indicate that RcsB, that presents a DNA binding domain, may be a positive regulator of cupD. This work intends to analyze the regulatory regions of these gene clusters to better understand their regulation and their relationship to each other. As a second goal, the ability of strains carrying mutations in these genes to inhibit growth of Dictyostelium discoideum will be evaluated in order to establish a simple infection model that will be used in other related projects as well.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

. Genes involved with Pseudomonas aeruginosa PA14 pathogenicity: characterization of the promoter regions and virulence assays in the Dictyostelium discoideum host model. 2008. Master's Dissertation - Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) São Paulo.