Dataset Information

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.

SUBMITTER: Yahr TL

PROVIDER: S-EPMC176720 | biostudies-other | 1995 Mar

REPOSITORIES: biostudies-other

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Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.

Yahr T L TL Hovey A K AK Kulich S M SM Frank D W DW

Journal of bacteriology 19950301 5

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. D ...[more]

PMID: 7868588

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Project description:The part of expression noise that is brought about by transcriptional regulation (represented here as NTR) is an important criterion for estimating the regulatory mode of a gene. However, characterization of NTR is an under-explored area, and there is little knowledge regarding the genome-wide NTR in the model pathogen Pseudomonas aeruginosa. Here, with a library of dual-color transcriptional reporters, we estimated the NTR for over 90% of the promoters in P. aeruginosa. Most promoters exhibit low NTR, while 42 and 115 promoters with high NTR were screened out in the exponential and the stationary growth phases, respectively. Specifically, a rearrangement of NTR was found in promoters involved in amino acid metabolism when bacteria enter the exponential phase. In addition, during the stationary phase, high NTR was found in a wide range of iron-related promoters involving siderophore synthesis and heme uptake, ExsA-regulated promoters involving bacterial virulence, and FleQ-regulated promoters involving biofilm development. We also found a large-scale negative dependence of transcriptional regulation between high-NTR promoters belonging to different functional categories. Our findings offer a global view of transcriptional heterogeneity in P. aeruginosa. IMPORTANCE The phenotypic diversity of Pseudomonas aeruginosa is frequently observed in research, suggesting that bacteria adopt strategies such as bet-hedging to survive ever-changing environments. Gene expression noise (GEN) is the major source of phenotypic diversity. Large GEN from transcriptional regulation (represented as NTR) represent an evolutionary necessity to maintain the copy number diversity of certain proteins in the population. Here, we provide a system-wide view of NTR in P. aeruginosa under nutrient-rich and stressed conditions. High NTR was found in genes involved in flagella biosynthesis and amino acid metabolism under both conditions. Specially, iron acquisition genes exhibited high NTR in the stressed condition, suggesting a great diversity of iron physiology in P. aeruginosa. We further revealed a global negative dependence of transcriptional regulation between those high-NTR genes under the stressed condition, suggesting a mutually exclusive relationship between different bacterial survival strategies.

Dataset Information

Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.

Publications

Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.

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