The pathogenic neisseriae contain an inactive rpoN gene and do not utilize the pilE σ54 promoter

Laskos, Lina; Dillard, Joseph P.; Seifert, H. Steven; Fyfe, Janet; Davies, John K.

doi:10.1016/s0378-1119(97)00664-1

Cited by 39 publications

(38 citation statements)

References 26 publications

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“…Indeed, this consensus sequence contains the GG-N8-(A/G)C motif which is very close to the Ϫ24/Ϫ12 consensus characteristic of a 54 dependent promoter (1,32). Though the rpoN gene is inactive in both N. meningitidis and N. gonorrhoeae (13), this promoter has been shown to play a major role in the cell contact regulation of both pilC1 and crgA (4,29).…”

Section: Resultsmentioning

confidence: 81%

The REP2 Repeats of the Genome ofNeisseria meningitidisAre Associated with Genes Coordinately Regulated during Bacterial Cell Interaction

2003

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Interaction with host cells is essential in meningococcal pathogenesis especially at the blood-brain barrier. This step is likely to involve a common regulatory pathway allowing coordinate regulation of genes necessary for the interaction with endothelial cells. The analysis of the genomic sequence of Neisseria meningitidis Z2491 revealed the presence of many repeats. One of these, designated REP2, contains a ؊24/؊12 type promoter and a ribosome binding site 5 to 13 bp before an ATG. In addition most of these REP2 sequences are located immediately upstream of an ORF. Among these REP2-associated genes are pilC1 and crgA, described as being involved in steps essential for the interaction of N. meningitidis with host cells. Furthermore, the REP2 sequences located upstream of pilC1 and crgA correspond to the previously identified promoters known to be induced during the initial localized adhesion of N. meningitidis with human cells. This characteristic led us to hypothesize that at least some of the REP2-associated genes were upregulated under the same circumstances as pilC1 and crgA. Quantitative PCR in real time demonstrated that the expression of 14 out of 16 REP2-associated genes were upregulated during the initial localized adhesion of N. meningitidis. Taken together, these data suggest that these repeats control a set of genes necessary for the efficient interaction of this pathogen with host cells. Subsequent mutational analysis was performed to address the role of these genes during meningococcus-cell interaction.

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Section: Resultsmentioning

confidence: 81%

The REP2 Repeats of the Genome ofNeisseria meningitidisAre Associated with Genes Coordinately Regulated during Bacterial Cell Interaction

2003

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“…Western blotting was performed as described previously (27). The dilution of the polyclonal antibody raised against E. coli RpoH antiserum was 1/4,000.…”

Section: Methodsmentioning

confidence: 99%

The RpoH-Mediated Stress Response in Neisseria gonorrhoeae Is Regulated at the Level of Activity

et al. 2004

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The general stress response in Neisseria gonorrhoeae was investigated. Transcriptional analyses of the genes encoding the molecular chaperones DnaK, DnaJ, and GrpE suggested that they are transcribed from 32 (RpoH)-dependent promoters upon exposure to stress. This was confirmed by mutational analysis of the 32 promoter of dnaK. The gene encoding the gonococcal RpoH sigma factor appears to be essential, as we could not isolate viable mutants. Deletion of an unusually long rpoH leader sequence resulted in elevated levels of transcription, suggesting that this region is involved in negative regulation of RpoH expression during normal growth. Transcriptional analyses and protein studies determined that regulation of the RpoH-mediated stress response is different from that observed in most other species, in which regulation occurs predominantly at the transcriptional and translational levels. We suggest that an increase in the activity of preformed RpoH is primarily responsible for induction of the stress response in N. gonorrhoeae.

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“…Only two intact genes encoding alternative sigma factors, rpoH (NGO0288) and ecf (NGO1944), were found. Laskos et al (11) have shown that there is also an inactive RpoN-like sigma factor, RLS, although this sequence feature (NGO1766) has not been annotated as such in the publicly available annotations of the N. gonorrhoeae strain FA1090 genome sequence (GenBank accession number AE004969; annotations at www .stdgen.lanl.gov, cmr.tigr.org/tigr-scripts/CMR/CmrHomePage .cgi, and www.ncbi.nlm.nih.gov/genomes/lproks.cgi). The ecf gene encodes a member of the extracytoplasmic function (ECF) family of sigma factors.…”

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confidence: 99%

Ecf, an Alternative Sigma Factor from Neisseria gonorrhoeae , Controls Expression of msrAB , Which Encodes Methionine Sulfoxide Reductase

et al. 2006

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A DNA microarray was used to identify genes transcribed in Neisseria gonorrhoeae using Ecf, an alternative sigma factor. No differences between the transcriptional profiles of strain FA1090 and a mutant where ecf had been inactivated could be detected when both were grown in vitro. We therefore constructed a gonococcal strain in which Ecf can be overexpressed. Some differentially expressed genes are clustered with ecf on the genome and appear to form a single transcriptional unit. Expression of the gene encoding MsrAB, which possesses methionine sulfoxide reductase activity, was also dependent on Ecf, suggesting that the regulon responds to oxidative damage. Western blotting confirmed that the increased level of MsrAB protein is dependent on the presence of Ecf.Bacterial sigma factors are essential components of the RNA polymerase holoenzyme and determine promoter selectivity and specificity. Bacteria usually contain at least one essential sigma factor, sigma-70, which is necessary for cell viability, as well as a number of accessory sigma factors that are often involved in responses to environmental stimuli or the phase of growth. The relative amount of RNA polymerase holoenzyme containing each sigma factor determines the amplitude of the expression of a specific collection of genes.We have searched the genome sequence of Neisseria gonorrhoeae strain FA1090 (GenBank accession number AE004969) for the presence of genes encoding sigma factors. As expected, there is a gene, rpoD, encoding sigma-70 (NGO0999). Only two intact genes encoding alternative sigma factors, rpoH (NGO0288) and ecf (NGO1944), were found. Laskos et al. (11) have shown that there is also an inactive RpoN-like sigma factor, RLS, although this sequence feature (NGO1766) has not been annotated as such in the publicly available annotations of the N. gonorrhoeae strain FA1090 genome sequence (GenBank accession number AE004969; annotations at www .stdgen.lanl.gov, cmr.tigr.org/tigr-scripts/CMR/CmrHomePage .cgi, and www.ncbi.nlm.nih.gov/genomes/lproks.cgi). The ecf gene encodes a member of the extracytoplasmic function (ECF) family of sigma factors. As the name suggests, ECF sigma factors from different bacterial species appear to respond specifically to a variety of extracytoplasmic stimuli. Characteristically, their activity is controlled by anti-sigma factors, and they control relatively small regulons (1). In most examples of this system investigated to date, the ECF sigma factors regulate not only their own expression but also that of the genes encoding the cognate anti-sigma factor, which are located in the same operon.We have used DNA microarrays to assess the role of the sigma factor Ecf in gonococci and show that it controls a small regulon which contains the msrAB gene, which encodes an unusual methionine sulfoxide reductase. MATERIALS AND METHODSBacterial strains, plasmids, and growth conditions. The bacterial strains and plasmids used in this study are listed in Table 1. Escherichia coli strain DH5␣ [F Ϫ endA1 thi-1 hsdR17 supE44 relA1 ⌬l...

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The pathogenic neisseriae contain an inactive rpoN gene and do not utilize the pilE σ54 promoter

Cited by 39 publications

References 26 publications

The REP2 Repeats of the Genome ofNeisseria meningitidisAre Associated with Genes Coordinately Regulated during Bacterial Cell Interaction

The REP2 Repeats of the Genome ofNeisseria meningitidisAre Associated with Genes Coordinately Regulated during Bacterial Cell Interaction

The RpoH-Mediated Stress Response in Neisseria gonorrhoeae Is Regulated at the Level of Activity

Ecf, an Alternative Sigma Factor from Neisseria gonorrhoeae , Controls Expression of msrAB , Which Encodes Methionine Sulfoxide Reductase

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