title: Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.
abstract: The transcriptional regulation of the Pseudomonas aeruginosa exoS gene was investigated. Expression of exoS in P. aeruginosa PA103 was dependent upon growth in a low-cation environment and the presence of a functional exsA gene. Promoter fusion analysis indicated that a 285-bp PstI-NsiI fragment, located 5' of the exoS coding region, contained a functional promoter for exoS. Expression of the reporter gene was inducible in a low-cation growth environment and required a functional copy of exsA. Divergent promoters, coordinately regulated with exoS transcription, were identified within the PstI-NsiI fragment. A fusion derivative of ExsA, MALA3A2, was shown to bind directly to the PstI-NsiI probe. DNase I protection analysis demonstrated that MALA3A2 bound to the intergenic region between the postulated -35 boxes of each promoter region. Northern (RNA) blot analysis with probes internal to and upstream of exoS demonstrated that separate, coordinately regulated mRNAs were expressed in P. aeruginosa. These data suggested that a locus, coregulated with exoS transcription, was located upstream of exoS. DNA sequence analysis of the exoS upstream region revealed three open reading frames, ORF 1, ORF 2, and ORF 3. ORF 1 demonstrated significant homology to the SycE/YerA protein of Yersinia sp. SycE/YerA is postulated to function as a chaperone for the YopE cytotoxin. The loci encoding YopE and ExoS show similarities in genetic organization, protein composition, and regulation.
authors.affiliation: Department of Microbiology, Medical College of Wisconsin, Milwaukee.
authors.forename: T L
authors.initials: TL
authors.lastname: Yahr
authors.forename: A K
authors.initials: AK
authors.lastname: Hovey
authors.forename: S M
authors.initials: SM
authors.lastname: Kulich
authors.forename: D W
authors.initials: DW
authors.lastname: Frank
mesh_terms: D036002:ADP Ribose Transferases; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins; D001483:Base Sequence; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D011993:Recombinant Fusion Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C081269:SycE protein, Yersinia; D015534:Trans-Activators; C063239:yopE protein, Yersinia; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases; C444820:exoenzyme S