Mutational analysis of genes involved in elastin hydrolysis in Pseudomonas aeruginosa

Abstract:

[Objective] Pseudomonas aeruginosa is an opportunistic pathogen responsible for a wide range of acute and chronic infections. When growing in the host, it secrets a lot of virulence factors including elastase. This work aimed to explore the genes involved in hydrolyzing ability of Pseudomonas aeruginosa towards elastin. [Methods] We performed a transposon mutagenesis analysis of P. aeruginosa PA68 to identify candidate genes involved in elastin hydrolysis. We also monitored the promoter activity of the lasB, a gene encoding the elastase, in the mutants and the wild-type by introducing a PlasB-lacZ transcriptional fusion. [Results] Four mutants with altered levels of elastase production were isolated (elastase activity relative to wild-type was shown in parenthesis): 10 (51%), 17 (131%), 27 (8%) and 84 (13%). Locations of the transposon were mapped to the genome lasA, galU, xcpZ and ptsP, respectively. The results of the lasB promoter’s activity were consistent with the elastase activity data (b-galactosidase activity relative to wild-type was shown in parenthesis): 10(75%), 17(201%), 27(54%) and 84(7%). [Conclusion] Taken together, the data build up a connection of these four genes with elastase production. This is the first report that gene galU and ptsP may be employed in the regulation of the biosynthesis of elastase.