Identification of a second endogenous Porphyromonas gingivalis insertion element

Wang, C Y; Bond, Vincent C.; Genco, Caroline Attardo

doi:10.1128/jb.179.11.3808-3812.1997

Cited by 22 publications

(26 citation statements)

References 14 publications

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“…Some of the phenotypic properties of the vimA-defective mutant are similar to the IS element-induced properties of P. gingivalis spontaneous mutants previously described (9,32,55,65). To determine the movement of any IS element in P. gingivalis FLL92, chromosomal DNA isolated from two vimA mutants (P. gingivalis FLL92 and P. gingivalis FLL92.1 [from two independent experiments]), P. gingivalis FLL32 (recA::ermF-ermAM), P. gingivalis FLL33 (recA::ermF-ermAM), and P. gingivalisW83 was digested with BamHI and probed with 32 P-labeled intragenic DNA from PGIS2 (65), ISPg4 (F. F. Dewhirst, unpublished data), ISPg5 (8), ISPg6 (Dewhirst, unpublished), ISPg7 (Dewhirst, unpublished), IS195 (32) and IS1126 (34).…”

Section: Vol 69 2001mentioning

confidence: 52%

“…Our results, however, do not rule out the possibility that the vimA gene is a regulatory gene whose product could negatively affect the expression of other genes that facilitate autoaggregation. The correlation of intragenomic changes due to the movement of IS elements and their effect on the phenotypic properties of P. gingivalis is well documented (9,32,55,65). While most of the P. gingivalis spontaneous mutants that were nonblack pigmented and had reduced proteolytic activities and virulence were IS element induced (9,32), no movement of the these elements was observed in the vimA-defective mutant compared to the wild-type strain.…”

Section: Discussionmentioning

confidence: 99%

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vimA Gene Downstream of recA Is Involved in Virulence Modulation in Porphyromonas gingivalis W83

et al. 2001

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A 0.9-kb open reading frame encoding a unique 32-kDa protein was identified downstream of the recA gene of Porphyromonas gingivalis. Reverse transcription-PCR and Northern blot analysis showed that both the recA gene and this open reading frame are part of the same transcriptional unit. This cloned fragment was insertionally inactivated using the ermF-ermAM antibiotic resistance cassette to create a defective mutant by allelic exchange. When plated on Brucella blood agar, the mutant strain, designated P. gingivalis FLL92, was non-black pigmented and showed significant reduction in beta-hemolysis compared with the parent strain, P. gingivalis W83. Arginine-and lysine-specific cysteine protease activities, which were mostly soluble, were approximately 90% lower than that of the parent strain. Expression of the rgpA, rgpB, and kgp protease genes was the same in P. gingivalis FLL92 as in the wild-type strain. In contrast to the parent strain, P. gingivalis FLL92 showed increased autoaggregration in addition to a significant reduction in hemagglutinating and hemolysin activities. In in vivo experiments using a mouse model, P. gingivalis FLL92 was dramatically less virulent than the parent strain. A molecular survey of this mutant and the parent strain using all known P. gingivalis insertion sequence elements as probes suggested that no intragenomic changes due to the movement of these elements have occurred in P. gingivalis FLL92. Taken together, these results suggest that the recA downstream gene, designated vimA (virulence-modulating gene), plays an important role in virulence modulation in P. gingivalis W83, possibly representing a novel posttranscriptional or translational regulation of virulence factors in P. gingivalis.

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Section: Vol 69 2001mentioning

confidence: 52%

Section: Discussionmentioning

confidence: 99%

vimA Gene Downstream of recA Is Involved in Virulence Modulation in Porphyromonas gingivalis W83

et al. 2001

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“…Such natural genetic engineering may result in gene activation or inactivation, as well as sequence duplication, deletion, or transposition (39,40). Reports of IS-like elements isolated individually (21,26,44) or identified by genomic sequence inspection (H. Dong, M. Duncan, T. Chen, F. Dewhirst, J. L. Galvin, R. Fleischmann, and C. Fraser, J. Dent. Res.…”

Section: Discussionmentioning

confidence: 99%

“…The restriction fragment length polymorphism (RFLP) pattern that they observed suggested considerable genetic heterogeneity among these strains. A second IS element in P. gingivalis, PGIS2, was described by Wang et al (44). As with IS1126, when PGIS2 was used as a probe in Southern analysis of several P. gingivalis strains, considerable diversity in the pattern of hybridizing fragments was noted.…”

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confidence: 99%

Characterization of Porphyromonas gingivalis Insertion Sequence-Like Element IS Pg5

et al. 2000

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Porphyromonas gingivalis, a black-pigmented, gram-negative anaerobe, is found in periodontitis lesions, and its presence in subgingival plaque significantly increases the risk for periodontitis. In contrast to many bacterial pathogens, P. gingivalis strains display considerable variability, which is likely due to genetic exchange and intragenomic changes. To explore the latter possibility, we have studied the occurrence of insertion sequence (IS)-like elements in P. gingivalis W83 by utilizing a convenient and rapid method of capturing IS-like sequences and through analysis of the genome sequence of P. gingivalis strain W83. We adapted the method of

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“…This diversity of clonal types may be caused by a variety of genetic mechanisms, especially IS-mediated genetic rearrangement (43). Combined with the fact that sequencing of the P. gingivalis genome has revealed a strikingly rich assortment of various IS elements (IS1126, ISPg2, IS195, ISPg4, ISPg5, ISPg6, ISPg7, and ISPg8) (2,7,25,30,31,48,50), it is likely that these IS elements promote genomic plasticity. This plasticity would then result in phenotypic changes in response to the complex environment in the periodontal pocket, thereby contributing to the overall pathogenicity of this pathogen.…”

Section: Discussionmentioning

confidence: 99%

Identification and Testing of Porphyromonas gingivalis Virulence Genes with a pPGIVET System

Lee

Hillman

et al. 2002

Infect Immun

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An in vivo expression technology (IVET) system was designed to identify previously unknown virulence genes of Porphyromonas gingivalis. Fourteen ivi (for in vivo induced) genes that are induced during infection in a mouse abscess model were identified in our study. Of these, seven had homology to genes in the NCBI database, and the rest had no homology to reported DNA sequences. In order to determine virulence-related properties of these genes, three mutant strains, deleted of ivi8 (no homology to genes in the database), ivi10 (homologous to a putative TonB-dependent outer membrane receptor protein), and ivi11 (an immunoreactive 33-kDa antigen PG125 in P. gingivalis), were created. The mutants were tested in a mouse abscess model for alterations in virulence relative to the wild type by a competition assay in BALB/c mice. After 5 days we observed the enrichment of the wild-type strain over mutant strains ⌬ivi10 and ⌬ivi11, which indicated that mutant strains ⌬ivi10 and ⌬ivi11 are less able to survive in this model than the wild-type strain, while ⌬ivi8 survives as well as the wild-type strain. We propose that knockout of these ivi genes reduced the ability of the mutated P. gingivalis to survive and cause infection compared to the wild-type strain at the site of injection. Also, in separate experiments, groups of mice were challenged with subcutaneous injections of each individual mutant strain (⌬ivi8, ⌬ivi10, and ⌬ivi11) or with the wild-type strain alone and were then examined to assess their general health status. The results showed that knockout of these ivi genes conferred a reduction in virulence. The ability of the mutants to invade KB cells compared to the wild type was also determined. Interestingly, the CFU counts of the mutant strain ⌬ivi10 recovered from KB cells were eight times lower than those of the wild type, indicating that this mutant has a lower capacity for invasion. These results demonstrate that IVET is a powerful tool in discovering virulence genes and the significant role that ivi genes play in the pathogenesis of this species.

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Identification of a second endogenous Porphyromonas gingivalis insertion element

Cited by 22 publications

References 14 publications

vimA Gene Downstream of recA Is Involved in Virulence Modulation in Porphyromonas gingivalis W83

vimA Gene Downstream of recA Is Involved in Virulence Modulation in Porphyromonas gingivalis W83

Characterization of Porphyromonas gingivalis Insertion Sequence-Like Element IS Pg5

Identification and Testing of Porphyromonas gingivalis Virulence Genes with a pPGIVET System

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