Transformation competence and type-4 pilus biogenesis in Neisseriagonorrhoeae – areview

Fussenegger, Martin; Rudel, Thomas; Barten, Roland; Ryll, Roland; Meyer, Thomas F.

doi:10.1016/s0378-1119(97)00038-3

Cited by 136 publications

(112 citation statements)

References 87 publications

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“…1 A. These results imply that fluorescent subunits are recycled, consistent with current models of pilus assembly that use a membrane pool of pilin subunits (23)(24)(25). However, the cell bodies were so highly fluorescent that we were not able to tell where this pool might be located.…”

Section: Resultssupporting

confidence: 75%

Direct observation of extension and retraction of type IV pili

Skerker

Berg

2001

Proc. Natl. Acad. Sci. U.S.A.

570

525

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Type IV pili are thin filaments that extend from the poles of a diverse group of bacteria, enabling them to move at speeds of a few tenths of a micrometer per second. They are required for twitching motility, e.g., in Pseudomonas aeruginosa and Neisseria gonorrhoeae, and for social gliding motility in Myxococcus xanthus. Here we report direct observation of extension and retraction of type IV pili in P. aeruginosa. Cells without flagellar filaments were labeled with an amino-specific Cy3 fluorescent dye and were visualized on a quartz slide by total internal reflection microscopy. When pili were attached to a cell and their distal ends were free, they extended or retracted at rates of about 0.5 m s ؊1 (29°C). They also flexed by Brownian motion, exhibiting a persistence length of about 5 m. Frequently, the distal tip of a filament adsorbed to the substratum and the filament was pulled taut. From the absence of lateral deflections of such filaments, we estimate tensions of at least 10 pN. Occasionally, cell bodies came free and were pulled forward by pilus retraction. Thus, type IV pili are linear actuators that extend, attach at their distal tips, exert substantial force, and retract.Pseudomonas aeruginosa ͉ twitching motility ͉ fluorescence M otile bacteria swim, swarm, or glide. Gliding refers to movement on a solid surface, such as glass or hard agar, without flagella, usually in the direction of the long axis of a cell (1). One form of gliding, known either as twitching motility or as social gliding, depends on 6-nm diameter filaments called type IV pili that extend from the pole of a cell (2-6). Twitching cells can exhibit chemotaxis (7) and͞or phototaxis (8). Twitching motility is required for formation of biofilms (9), and social gliding is important for formation of fruiting bodies (10).We studied twitching motility in Pseudomonas aeruginosa, a common Gram-negative bacterium that acts as an opportunistic human pathogen. It causes bacteremia in burn victims, infections of the urinary tract in catheterized patients, chronic lung infections in patients with cystic fibrosis, and acute ulcerative keratitis in users of extended-wear soft-contact lenses (11,12). P. aeruginosa has a single flagellum and multiple type IV pili; thus, it can move by swimming or twitching motility. Pili-mediated adhesion is a known virulence factor (13) and the molecular genetics of pilus assembly has been studied extensively (14). It is thought that twitching motility allows cells to spread on body surfaces during infection (6).Type IV pili have been seen with an electron microscope (15, 16) but have not been visualized in vivo. Recently, the motion of bacterial flagella was analyzed by labeling intact cells with amino-specific fluorescent dyes (17). By labeling cells of P. aeruginosa with an amino-specific Cy3, we have observed directly pilus extension, pilus retraction, and retraction-mediated cell movement. Our work confirms and extends that of Mertz et al. (18), who used an optical trap to measure the force of retraction of pi...

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Section: Resultssupporting

confidence: 75%

Direct observation of extension and retraction of type IV pili

Skerker

Berg

2001

Proc. Natl. Acad. Sci. U.S.A.

570

525

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“…Notably, many Tfppossessing organisms are also naturally transformable, including Neisseria gonorrhoeae, Pseudomonas stutzeri and Acinetobacter calcoaceticus (Fussenegger et al, 1997;Graupner et al, 2000;Palmen & Hellingwerf, 1997). In Synechocystis sp.…”

Section: Introductionmentioning

confidence: 99%

The competence gene, comF, from Synechocystis sp. strain PCC 6803 is involved in natural transformation, phototactic motility and piliation

2006

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The competence gene, comF, from Synechocystis sp. strain PCC 6803 is involved in natural transformation, phototactic motility and piliation The gene slr0388 was previously annotated to encode a hypothetical protein in Synechocystis sp. strain PCC 6803. When a positively phototactic strain of this cyanobacterium was insertionally inactivated at slr0388, the mutants were not transformable, and appeared to aggregate as a result of increased bundling of type IV pili. Also, these mutants were rendered non-phototactic compared to the wild-type. Quantitative real-time PCR revealed a 3?5-fold increase in pilA1 transcript levels in the mutant over wild-type cells, while there were no changes in the level of pilT1 and comA transcripts. Supernatant from mutant liquid culture contained more PilA1 protein, confirmed by mass spectrometric analysis, compared to the wild-type cells, which corresponded to the increase in pilA1 transcripts. The increase in PilA1 subunits may contribute to the bundling morphology of pili that was observed, which in turn may act to retard DNA uptake by hindering the retraction of pili. This gene is therefore proposed to be designated comF, as it possesses a phosphoribosyltransferase domain, a distinguishing feature of other ComF proteins of naturally transformable heterotrophic bacteria. This report is the second of a competence-related gene from Synechocystis sp. strain PCC 6803, the product of which does not show homology to other well-studied type IV pili proteins.

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“…Thus, no mutations of type IV pilus biogenesis genes have resulted in the accumulation of free pilin in the periplasmic space and no periplasmic chaperones have been described. This has led some Soluble protein and type IV pilus biogenesis investigators to propose models for type IV pilus biogenesis that include no periplasmic phase of export, but instead envisage a structure that spans the inner and outer membranes (Fussenegger et al, 1997 ;Iredell & Manning, 1994 ;Hobbs & Mattick, 1993). Recently, the use of conditional double-knockout mutants has allowed the dissection of type IV pilus formation into three different phases -pilin processing, pilus formation and pilus extrusion (Wolfgang et al, 1998(Wolfgang et al, , 2000.…”

Section: Introductionmentioning

confidence: 99%

BfpU, a soluble protein essential for type IV pilus biogenesis in enteropathogenic Escherichia coli

et al. 2002

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A cluster of 14 genes located on the large plasmid of enteropathogenic Escherichia coli (EPEC) strains is sufficient to direct the biogenesis of the type IV bundle-forming pilus (BFP) in a recombinant E. coli host. The fifth gene in the cluster, bfpU, encodes a protein that is predicted to be localized to the periplasmic space. To determine whether BfpU is necessary for pilus biogenesis, the authors constructed a non-polar bfpU mutant EPEC strain by allelic exchange. The mutant strain was unable to perform localized adherence and auto-aggregation, two phenotypes associated with BFP expression, and it failed to make BFP. These phenotypes were restored to the bfpU mutant by a plasmid containing bfpU. There was no difference between the wild-type and bfpU mutant strains in their expression or processing of the pre-pilin protein or in their localization of the pilin protein in the inner and outer membranes. Fractionation studies revealed that BfpU is completely soluble and is detected in both the periplasm and the cytoplasm. Thus, BfpU represents a novel protein required for type IV pilus assembly.

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Transformation competence and type-4 pilus biogenesis in Neisseriagonorrhoeae – areview

Cited by 136 publications

References 87 publications

Direct observation of extension and retraction of type IV pili

Direct observation of extension and retraction of type IV pili

The competence gene, comF, from Synechocystis sp. strain PCC 6803 is involved in natural transformation, phototactic motility and piliation

BfpU, a soluble protein essential for type IV pilus biogenesis in enteropathogenic Escherichia coli

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