title: Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression.
abstract: We report the discovery of the lasR gene, which positively regulates elastase expression in Pseudomonas aeruginosa PAO1. The lasR gene was cloned by its ability to restore a positive elastase phenotype in strain PA103, a strain which possesses the elastase structural gene (lasB) but fails to synthesize the enzyme. Nucleotide sequence analysis revealed an open reading frame of 716 nucleotides encoding a protein of approximately 27 kDa. A labeled LasR protein of 27 kDa was detected in Escherichia coli by using a T7 RNA polymerase expression system. A chromosomal deletion mutant of the lasR gene was constructed in PAO1 by gene replacement. This mutant (PAO-R1) is devoid of elastolytic activity and elastase antigen. The deduced amino acid sequence of LasR is 27% homologous to the positive activator LuxR of Vibrio fischeri and the suspected activator 28K-UvrC of E. coli. Northern (RNA) analysis of total cellular RNA from PAO1, PAO-R1, and PAO-R1 containing the lasR gene on a multicopy plasmid (pMG1.7) revealed that a functional lasR gene is required for transcription of the elastase structural gene (lasB).
authors.affiliation: Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York 14642.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gambello
authors.forename: B H
authors.initials: BH
authors.lastname: Iglewski
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics*; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000096:biosynthesis; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000737:chemistry*; D014158:Transcription, Genetic
chemical_list: D015534:Trans-Activators; D010196:Pancreatic Elastase