A consensus Porphyromonas gingivalis promoter sequence

Jackson, Christopher J.

doi:10.1016/s0378-1097(00)00131-2

Cited by 19 publications

(29 citation statements)

References 29 publications

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“…RT-PCR data indicated that these two genes are cotranscribed (data not shown). The region upstream of the putative 5-methylthioadenosine nucleosidase-S-adenosylhomocysteine nucleosidase gene contained prokaryote promoter consensus sequences identified using the Promoter Predictions search tool of the Berkeley Drosophila Genome Project (http://www-.fruitfly.org) and by visual comparison with a set of predicted P. gingivalis consensus promoter sequences (20). Thus, transcription of luxS may require the promoter of the upstream ORF.…”

Section: Resultsmentioning

confidence: 99%

Signaling System in Porphyromonas gingivalis Based on a LuxS Protein

et al. 2001

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The luxS gene of quorum-sensing Vibrio harveyi is required for type 2 autoinducer production. We identified a Porphyromonas gingivalis open reading frame encoding a predicted peptide of 161 aa that shares 29% identity with the amino acid sequence of the LuxS protein of V. harveyi. Conditioned medium from a late-log-phase P. gingivalis culture induced the luciferase operon of V. harveyi, but that from a luxS insertional mutant did not. In P. gingivalis, the expression of luxS mRNA was environmentally controlled and varied according to the cell density and the osmolarity of the culture medium. In addition, differential display PCR showed that the inactivation of P. gingivalis luxS resulted in up-regulation of a hemin acquisition protein and an argininespecific protease and reduced expression of a hemin-regulated protein, a TonB homologue, and an excinuclease. The data suggest that the luxS gene in P. gingivalis may function to control the expression of genes involved in the acquisition of hemin.Quorum sensing, the density-dependent regulation of gene expression, is widespread among both gram-negative and gram-positive bacteria. Quorum sensing involves the synthesis and detection of extracellular signaling molecules termed autoinducers (AIs) (2, 13). Quorum sensing in gram-negative bacteria was first described for the marine symbiotic organism Vibrio fischeri. The number of acyl homoserine lactone (HSL) AI molecules in a given culture of V. fischeri increases as the cell density increases, and once a critical concentration of AI is reached, a signal transduction cascade that leads to the production of bioluminescence by cells is initiated (15). Components of this system include LuxI, an acyl HSL synthase that directs synthesis of 3-oxo-hexanoyl-HSL (V. fischeri AI-1); AinS, an acyl HSL synthase that catalyzes the synthesis of octanoyl-HSL (V. fischeri AI-2); and LuxR, a transcriptional activator necessary for responses to V. fischeri AI-1 (10). Homologues of the luxI and luxR genes of V. fischeri have been described now for a range of gram-negative bacteria and are responsible for the density-dependent regulation of quite diverse physiological functions (1,2,13,30,41). Light production by Vibrio harveyi is similarly under the control of quorumsensing systems, however the bioluminescence genes are not regulated by homologues of the V. fischeri LuxI and LuxR proteins (3, 4). Rather, in V. harveyi, quorum sensing involves two parallel regulatory systems. Signaling system 1 is dependent on two genes, luxL and luxM, for the synthesis of N-3-hydroxybutanoyl-L-HSL (V. harveyi AI-1), and signal detection is mediated by the sensor kinase LuxN (3,26). LuxM shows sequence homology to V. fischeri AinS (10). Signaling system 2 requires the luxS gene for the synthesis of V. harveyi AI-2, a non-HSL AI, the structure of which is unknown (41, 42). The primary sensor for V. harveyi AI-2 is thought to be LuxP, and the LuxP-AI-2 complex interacts with LuxQ to initiate signal transduction (4, 26). Signals from both LuxN and LuxQ feed i...

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Section: Resultsmentioning

confidence: 99%

Signaling System in Porphyromonas gingivalis Based on a LuxS Protein

et al. 2001

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“…Primer extension analysis of ihtB showed that the transcription start point is 267 bases upstream from the methionine translation start codon (21). A nearly perfect invert repeat sequence was identified 45 nucleotides downstream from the stop codon, between bases 1391 and 1439 (AGAGCACTtATCGAGAAga aggacttgccgatTTCTCGATgAGTGCTCT).…”

Section: Resultsmentioning

confidence: 99%

Characterization of a Novel Outer Membrane Hemin-Binding Protein of Porphyromonas gingivalis

et al. 2000

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Porphyromonas gingivalis is a gram-negative, anaerobic coccobacillus that has been implicated as a major etiological agent in the development of chronic periodontitis. In this paper, we report the characterization of a protein, IhtB (iron heme transport; formerly designated Pga30), that is an outer membrane hemin-binding protein potentially involved in iron assimilation by P. gingivalis. IhtB was localized to the cell surface of P. gingivalis by Western blot analysis of a Sarkosyl-insoluble outer membrane preparation and by immunocytochemical staining of whole cells using IhtB peptide-specific antisera. The protein, released from the cell surface, was shown to bind to hemin using hemin-agarose. The growth of heme-limited, but not heme-replete, P. gingivalis cells was inhibited by preincubation with IhtB peptide-specific antisera. The ihtB gene was located between an open reading frame encoding a putative TonB-linked outer membrane receptor and three open reading frames that have sequence similarity to ATP binding cassette transport system operons in other bacteria. Analysis of the deduced amino acid sequence of IhtB showed significant similarity to the Salmonella typhimurium protein CbiK, a cobalt chelatase that is structurally related to the ATP-independent family of ferrochelatases. Molecular modeling indicated that the IhtB amino acid sequence could be threaded onto the CbiK fold with the IhtB structural model containing the active-site residues critical for chelatase activity. These results suggest that IhtB is a peripheral outer membrane chelatase that may remove iron from heme prior to uptake by P. gingivalis.

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“…The most extensively characterized UP element is an ATrich sequence located between Ϫ40 and Ϫ60 in the rrnB P1 promoter of E. coli (19,20), which stimulates promoter activity at least 30-fold (19). UP-like elements found upstream of Bacteroidetes promoters have been recognized in B. fragilis (1) and P. gingivalis (27). A genome-wide survey of putative promoters in members of the phylum Bacteroidetes also showed that UPlike sequences occur at ϳ20 bp upstream of the Ϫ33 promoter motifs (Fig.…”

Section: Discussionmentioning

confidence: 98%

“…This is in spite of the ubiquitous distribution of members of the phylum Bacteroidetes (6, 14, 30, 31); their importance as pathogens of fish (15, 42), birds (54), and humans (7); and their roles in transforming high-molecularweight carbon compounds in soil and aquatic environments (14). Most research on gene regulation in this phylum has targeted Bacteroides (4,11,32,49,55,57) and, to a lesser extent, Porphyromonas (27,43,57,60). Early examination of the transcriptional signals in Bacteroides fragilis indicated that its promoters exhibited features distinct from those of proteobacteria (4, 55).…”

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confidence: 99%

Mutational Analysis of theompAPromoter fromFlavobacterium johnsoniae

Chen¹,

Bagdasarian²,

Kaufman

et al. 2007

J Bacteriol

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Sequences that mediate the initiation of transcription in Flavobacterium species are not well known. The majority of identified Flavobacterium promoter elements show homology to those of other members of the phylum Bacteroidetes, but not of proteobacteria, and they function poorly in Escherichia coli. In order to analyze the Flavobacterium promoter structure systematically, we investigated the ؊33 consensus element, ؊7 consensus element, and spacer length of the Flavobacterium ompA promoter by measuring the effects of site-directed mutations on promoter activity. The nonconserved sequences in the spacer region and in regions close to the consensus motifs were randomized in order to determine their importance for promoter activity. Most of the base substitutions in these regions caused large decreases in promoter activity. The optimal ؊33/؊7 motifs (TTTG/TANNTTTG) were identical to Bacteroides fragilis ABfr consensus ؊33/؊7 promoter elements but lacked similarity to the E. coli 70 promoter elements. The length of the spacer separating the ؊33 and ؊7 motifs of the ompA promoter also had a pronounced effect on promoter activity, with 19 bp being optimal. In addition to the consensus promoter elements and spacer length, the GC content of the core promoter sequences had a pronounced effect on Flavobacterium promoter activity. This information was used to conduct a scan of the Flavobacterium johnsoniae and B. fragilis genomes for putative promoters, resulting in 188 hits in B. fragilis and 109 hits in F. johnsoniae.Studies of molecular regulatory mechanisms in bacteria of the phylum Bacteroidetes are underdeveloped because of a lack of genetic tools and the poorly characterized genetic elements (2,40,51). This is in spite of the ubiquitous distribution of members of the phylum Bacteroidetes (6, 14, 30, 31); their importance as pathogens of fish (15, 42), birds (54), and humans (7); and their roles in transforming high-molecularweight carbon compounds in soil and aquatic environments (14). Most research on gene regulation in this phylum has targeted Bacteroides (4,11,32,49,55,57) and, to a lesser extent, Porphyromonas (27,43,57,60). Early examination of the transcriptional signals in Bacteroides fragilis indicated that its promoters exhibited features distinct from those of proteobacteria (4, 55). Similar promoter structures have also been reported in other members of the phylum Bacteroidetes, such as Porphyromonas gingivalis (27), Pedobacter heparinus (formerly Flavobacterium heparinum) (5), and Prevotella loescheii (37). Key findings were a unique pair of Ϫ33/Ϫ7 element consensus sequences (TTTG/TANNTTTG) separated by a spacer of variable length (generally 19 to 21 nucleotides) that are possibly involved in promoter recognition in members of the phylum Bacteroidetes and that these elements are not homologous to Escherichia coli 70 promoters (21). Genome-wide analysis of the sigma factors from 240 bacteria revealed that, unlike proteobacteria, members of the phylum Bacteroidetes lack typical 70 sequences, which accoun...

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A consensus Porphyromonas gingivalis promoter sequence

Cited by 19 publications

References 29 publications

Signaling System in Porphyromonas gingivalis Based on a LuxS Protein

Signaling System in Porphyromonas gingivalis Based on a LuxS Protein

Characterization of a Novel Outer Membrane Hemin-Binding Protein of Porphyromonas gingivalis

Mutational Analysis of theompAPromoter fromFlavobacterium johnsoniae

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