title: Analysis of the Pseudomonas aeruginosa elastase (lasB) regulatory region.
abstract: The enzyme elastase is an important virulence factor of the opportunistic human pathogen Pseudomonas aeruginosa. Previous studies have shown that expression of the P. aeruginosa elastase gene (lasB) requires both an activator protein, LasR, and an N-acylhomoserine lactone compound termed Pseudomonas autoinducer (PAI). In this study, we analyzed the lasB promoter region to learn more about lasB activation by LasR and PAI. We report that the lasB transcriptional start is located 141 nucleotides upstream from the lasB translational start. It was also discovered that the lasB promoter region contains two putative operator sequences (OP1 and OP2) that are similar to each other and the Vibrio fischeri lux operator. OP1 is located directly upstream from, and may overlap with, the lasB promoter region, and OP2 is centered 102 nucleotides upstream from the lasB transcriptional start site. To study the effects of these putative operators and other sequences upstream from the lasB transcriptional start site on lasB activation, a series of transcriptional lasBp-lacZ gene fusions was constructed. Data from these fusions indicate that both putative operators are involved in LasR- and PAI-mediated lasB activation, with OP1 being more important than OP2.
authors.affiliation: Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
authors.forename: L
authors.initials: L
authors.lastname: Rust
authors.forename: E C
authors.initials: EC
authors.lastname: Pesci
authors.forename: B H
authors.initials: BH
authors.lastname: Iglewski
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D004790:Enzyme Induction; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D008666:Metalloendopeptidases / Q000235:genetics*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009875:Operator Regions, Genetic; D010196:Pancreatic Elastase / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D017384:Sequence Deletion; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D007783:Lactones; C080365:LasR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; C085113:Pseudomonas aeruginosa autoinducer; D006714:Homoserine; D010196:Pancreatic Elastase; D008666:Metalloendopeptidases; C043859:pseudolysin, Pseudomonas aeruginosa