[Mutational analysis of genes involved in elastin hydrolysis in Pseudomonas aeruginosa]

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.

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 Pl(asB-)lacZ transcriptional fusion.

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 (fbetagalactosidase activity relative to wild-type was shown in parenthesis): 10(75%), 17(201%), 27(54%) and 84(7%).

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.