The α subunit of RNA polymerase specifically inhibits expression of the porin genes ompF and ompC in vivo and in vitro in Escherichia coli

Bowrin, V

doi:10.1016/0378-1097(94)90452-9

Cited by 8 publications

(10 citation statements)

References 18 publications

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“…This nature of rpoA mutation was suggested, though not demonstrated, in a previous study of OmpR-activated promoters in E. coli (36). Indeed, in a separate study, overexpression of a was shown to reduce OmpR-dependent activation of the ompF and ompC promoters (6 (32). Our observation that greater overproduction of at from pNMD120 caused reduction also of PRN and FIM expression is consistent with this model, though it does not provide compelling evidence for it.…”

Section: Discussionsupporting

confidence: 51%

Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

et al. 1994

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In Bordetella pertussis, expression of virulence factors is controlled by the Bvg proteins, which comprise a sensor-regulator two-component signal transduction system. Previously, we described a mutant strain of B.pertussis that had reduced transcription of pertussis toxin and adenylate cyclase toxin genes, while other virulence factors were relatively unaffected. We obtained a B. pertussis clone that repaired the defect in both this strain and an independent mutant strain with a similar phenotype when introduced onto the chromosome by allelic exchange. Further analysis revealed that the mutations were just upstream of the translational start site of the rpoA gene encoding the a subunit of RNA polymerase. We confirmed that these mutations were responsible for the mutant phenotype by site-directed mutagenesis. Our hypothesis that these mutations cause an overexpression of rpoA was confirmed by Western immunoblotting and translational fusion analysis. Corroboration of this effect was obtained by overexpressing rpoA on a plasmid in wild-type B. pertussis, which caused the same phenotype as the mutants showed. Conclusions in regard to the identity of the transcription activator of the toxin genes are discussed.

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Section: Discussionsupporting

confidence: 51%

Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

et al. 1994

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“…In addition to DNA binding, OmpR was shown to interact productively with RNA polymerase to effectively regulate its transcription (Bowrin et al, 1994). Analysis of OmpR structure also revealed that the large loop connecting helices a2 and a3 in the N-terminal region was the probable site of interaction with the a subunit of RNA polymerase RpoA (Martinez-Hackert & Stock, 1997).…”

Section: Discussionmentioning

confidence: 99%

Positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis

Wang

Ding

et al. 2009

Microbiology

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OmpR has been demonstrated to negatively regulate the expression of the flagellar master operon flhDC in a wide variety of bacterial species. Here we report the positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis. A s 70 -dependent promoter was identified by primer extension analysis and an active region with two conserved OmpR-binding sites around the flhDC promoter was confirmed. To confirm the regulation of flhDC expression by OmpR, flhDC as well as the downstream flagellar genes fliA, flgD, flgA, flgM, fliC and flaA were fused to lacZ, and decreased expression of all these genes in an ompR mutant (DompR) was detected. Furthermore, DompR was defective in bacterial motility and flagella synthesis. This defect was due to the low level of expression of flhDC in DompR since overproduction of FlhDC in DompR restored bacterial motility. The importance of two conserved OmpR-binding sites around the flhDC promoter region in the regulation of flhDC expression by OmpR was demonstrated by the fact that mutation of either one or both sites significantly decreased the promoter activity in the wild-type but not in DompR. The binding of OmpR to these two sites was also demonstrated by DNA mobility shift assay. The possible mechanism underlying this positive regulation in Y. pseudotuberculosis is discussed. To our knowledge, this is the first report to demonstrate that OmpR positively regulates flhDC expression. INTRODUCTIONFlagella, the unique structure for motility, represent an important advantage for bacteria in moving towards favourable conditions or in avoiding detrimental environments. In pathogenic bacteria, flagella are usually considered as virulence factors (Josenhans & Suerbaum, 2002), and they play crucial roles in adhesion, colonization and biofilm formation of many bacteria such as Pseudomonas aeruginosa (Toutain et al., 2007), Escherichia coli (Pratt & Kolter, 1998), Vibrio cholerae (Gardel & Mekalanos, 1996) and Salmonella typhimurium (Ciacci-Woolwine et al., 1998). Flagellar gene regulation and assembly have been extensively characterized in E. coli and S. enterica serovar Typhimurium (Aldridge & Hughes, 2002). Over 60 genes, which are arranged into three classes (class I, class II and class III), are coordinately regulated and expressed in a transcriptional hierarchy (Chilcott & Hughes, 2000;Kanehisa et al., 2004;Kutsukake et al., 1990). Transcription of the downstream flagellar genes is dependent on a high expression level of some upstream genes. At the top of this hierarchy is the master operon composed of the genes flhD and flhC. FlhD and FlhC together form a heterohexameric transcriptional activator that binds to the class II operons (Wang et al., 2006). Due to the key role of flhDC in flagella synthesis, the regulation of its expression has been studied at both the transcriptional and post-transcriptional levels (Soutourina & Bertin, 2003). Many regulatory proteins, such as H-NS (Bertin et al., 1994;Soutourina et al., 1999), cAMP-CAP complex (catabolite gene activator protei...

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“…4) (Bowrin et al 1994;reviewed in Pratt & Silhavy 1994). The ¹35 and ¹10 regions of the ompF and ompC genes have low identity (50%) with the consensus sequence which necessitates binding of OmpR-P, a j70 type DNA binding protein, for transcriptional regulation (Mizuno et al 1983a,b).…”

Section: Differential Regulation Of Ompf and Ompc By Ompr-pmentioning

confidence: 99%

Signal transduction via the histidyl‐aspartyl phosphorelay

1997

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The histidyl-aspartyl phosphorelay, formerly described as the two-component system, is the predominant mode of signal transduction in bacteria. Adaptation to environmental changes occurs through a sensor histidine protein kinase and a response regulator. The histidine protein kinase is usually a transmembrane receptor and the response regulator is a cytoplasmic protein.Together the histidyl-aspartyl phosphorelay proteins mediate reversible phosphorylation events that control downstream effectors. Following autophosphorylation at a conserved histidine residue, the histidine kinase serves as a phospho-donor for the response regulator. Once phosphorylated, the response regulator mediates changes in gene expression or cellular locomotion. The EnvZ-OmpR phosphorelay system in Escherichia coli, which monitors external osmolarity and responds by differentially modulating the expression of the OmpF and OmpC major outer membrane porins, will be described as a model system. While histidine kinases were thought to be present only in prokaryotes, they have recently been identified in eukaryotic systems. Here, we review the unique and conserved features of this growing family of signal transducers.

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The α subunit of RNA polymerase specifically inhibits expression of the porin genes ompF and ompC in vivo and in vitro in Escherichia coli

Cited by 8 publications

References 18 publications

Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis

Positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis

Signal transduction via the histidyl‐aspartyl phosphorelay

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