Cloning and transcriptional regulation of the elastase lasA gene in mucoid and nonmucoid Pseudomonas aeruginosa.

The lasA gene (whose product is involved in the production of extracellular elastolytic activity) was isolated from a genomic bank containing DNA from Pseudomonas aeruginosa FRD1. Recombinant plasmid pELA1, containing the lasA gene, complemented the temperature-sensitive elastase mutation (lasA1) in P. aeruginosa PAO-E64. The lasA gene was physically mapped on plasmid pELA1 by deletion analysis and transposon mutagenesis. The direction of transcription of lasA was determined with a promoterless chloramphenicol acetyltransferase cartridge. The lasA-chloramphenicol acetyltransferase plasmid was transferred to isogenic mucoid and nonmucoid strains of P. aeruginosa FRD; the transcription of lasA-chloramphenicol acetyltransferase was slightly higher in the nonmucoid strain.