Molecular Characterization of Low‐Molecular‐Weight Component Protein, Flp, in <i>Actinobacillus actinomycetemcomitans</i> Fimbriae

Inoue, Tetsuyoshi; Tanimoto, Ichiro; Ohta, Hiroyuki; Kato, Kimiko; Murayama, Yoji; Fukui, Kiichi

doi:10.1111/j.1348-0421.1998.tb02280.x

Cited by 79 publications

(102 citation statements)

References 22 publications

(29 reference statements)

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“…These genes are homologous to components of type II secretion systems that are involved in type IV pilus biogenesis (unpublished data). Flp is the major component of fibrils in A. actinomycetemcomitans (41), and the gene encoding Flp recently has been shown to be required for fibril production (S.C.K., P.J.P., R.D., D. H. Fine, D.H.F., and J. B. Kaplan, unpublished data).…”

Section: Discussionmentioning

confidence: 99%

Phylogeny of genes for secretion NTPases: Identification of the widespread tadA subfamily and development of a diagnostic key for gene classification

Planet

Kachlany

DeSalle

et al. 2001

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

186

166

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Macromolecular transport systems in bacteria currently are classified by function and sequence comparisons into five basic types. In this classification system, type II and type IV secretion systems both possess members of a superfamily of genes for putative NTP hydrolase (NTPase) proteins that are strikingly similar in structure, function, and sequence. These include VirB11, TrbB, TraG, GspE, PilB, PilT, and ComG1. The predicted protein product of tadA, a recently discovered gene required for tenacious adherence of Actinobacillus actinomycetemcomitans, also has significant sequence similarity to members of this superfamily and to several unclassified and uncharacterized gene products of both Archaea and Bacteria. To understand the relationship of tadA and tadA-like genes to those encoding the putative NTPases of type II͞IV secretion, we used a phylogenetic approach to obtain a genealogy of 148 NTPase genes and reconstruct a scenario of gene superfamily evolution. In this phylogeny, clear distinctions can be made between type II and type IV families and their constituent subfamilies. In addition, the subgroup containing tadA constitutes a novel and extremely widespread subfamily of the family encompassing all putative NTPases of type IV secretion systems. We report diagnostic amino acid residue positions for each major monophyletic family and subfamily in the phylogenetic tree, and we propose an easy method for precisely classifying and naming putative NTPase genes based on phylogeny. This molecular key-based method can be applied to other gene superfamilies and represents a valuable tool for genome analysis.conjugation ͉ ATPase ͉ Archaea ͉ molecular key ͉ Walker box

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Section: Discussionmentioning

confidence: 99%

Phylogeny of genes for secretion NTPases: Identification of the widespread tadA subfamily and development of a diagnostic key for gene classification

Planet

Kachlany

DeSalle

et al. 2001

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

186

166

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“…The genes appear to be arranged in an operon. Our results show that the tad locus encodes a secretion system responsible for the secretion and assembly of bundled pili (18,21). Remarkably, tad-related loci are present in diverse Bacteria and Archaea, and we have proposed that the role of tad-like loci in other microbes is to mediate adherence in different environments (16).…”

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confidence: 90%

“…Using a rat model, we compared the wild-type strain to mutant strains defective in flp-1 or tadA. Flp1 is the major pilus subunit (18,21), and TadA is an ATP hydrolase that is likely to energize or serve as a chaperone in the secretion and assembly of Flp1 (22). Our results show that this model system can be used to study disease resembling LAP of humans.…”

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confidence: 99%

Tight-adherence genes of Actinobacillus actinomycetemcomitans are required for virulence in a rat model

Schreiner

Sinatra

Kaplan

et al. 2003

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

152

165

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Actinobacillus actinomycetemcomitans is a Gram-negative coccobacillus that has been associated with localized aggressive periodontitis and infections of the heart, brain, and urinary tract. Wild-type clinical isolates have the remarkable ability to adhere tenaciously and nonspecifically to solid surfaces such as glass, plastic, and hydroxyapatite. Adherence by A. actinomycetemcomitans is mediated by the tight-adherence (tad) gene locus, which consists of 14 genes (flp-1-flp-2-tadV-rcpCAB-tadZABCDEFG). All but 2 of the genes have been shown to be required for the secretion and assembly of long, bundled Flp1 fibrils. To test whether the tad locus is required for colonization and disease, we developed a rat model for periodontal disease. To mimic the natural route of infection, Sprague-Dawley rats were inoculated orally by adding bacteria directly to their food for 8 days. After inoculation with wild-type or mutant strains defective in adherence (flp-1 and tadA), the rats were assessed for colonization of the oral cavity and pathogenesis. Wild-type A. actinomycetemcomitans was able to colonize and persist for at least 12 weeks in the oral cavity, elicit a humoral immune response, and cause significant bone loss in rats. In contrast, rats fed flp-1 or tadA mutant strains showed no bone loss and their immune responses were indistinguishable from those of the uninoculated controls. These results demonstrate the critical importance of the tad locus in the colonization and pathogenesis of A. actinomycetemcomitans. nonspecific adherence ͉ tad genes ͉ pathogenesis ͉ localized juvenile periodontitis

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“…The bacteria are known to produce several virulence factors, including a leukotoxin and a cytolethal distending toxin, and they adhere to solid surfaces and cells (Taichman and Wilton, 1981;Kolodrubetz et al, 1989;Lally et al, 1989;Eastcott et al, 1990;Mangan et al, 1991;Fives-Taylor et al, 1999;van Winkelhoff and Slots, 1999;Kachlany et al, 2001a;Narayanan et al, 2002;Henderson et al, 2003;Rose et al, 2003;Paturel et al, 2004;Rhodes et al, 2005;Diaz et al, 2006;Fine et al, 2005Fine et al, , 2006Smith and Bayles, 2006). Clinical isolates autoaggregate and secrete long, bundled pili (Flp fibrils) (Holt et al, 1980;Scannapieco et al, 1987;Rosan et al, 1988;Inoue et al, 1998;Kachlany et al, 2001b;Henderson et al, 2003;Fine et al, 2006). In vitro A. actinomycetemcomitans can produce rare, stable, nonadherent, and nonaggregative genetic variants that form smooth, large colonies and fail to produce Flp fibrils (Wyss, 1989;Inouye et al, 1990;Fine et al, 1999Fine et al, , 2006Kachlany et al, 2000Kachlany et al, , 2001aHenderson et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

tfoX (sxy)-dependent transformation of Aggregatibacter (Actinobacillus) actinomycetemcomitans

Bhattacharjee

Fine

Figurski

2007

Gene

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AbstracttfoX (sxy) is a regulatory gene needed to turn on competence genes. Aggregatibacter (Actinobacillus) actinomycetemcomitans has a tfoX gene that is important for transformation. We cloned this gene on an IncQ plasmid downstream of the inducible tac promoter. When this plasmid was resident in cells of A. actinomycetemcomitans and tfoX was induced, the cells became competent for transformation. Several strains of A. actinomycetemcomitans, including different serotypes, as well as rough (adherent) and isogenic smooth (nonadherent) forms were tested. Only our two serotype f strains failed to be transformed. With the other strains, we could easily get transformants with extrachromosomal plasmid DNA when closed circular, replicative plasmid carrying an uptake signal sequence (USS) was used. When a replicative plasmid carrying a USS and cloned DNA from the chromosome of A. actinomycetemcomitans was linearized by digestion with a restriction endonuclease or when genomic DNA was used directly, the outcome was allelic exchange. To facilitate allelic exchange, we constructed a suicide plasmid (pMB78) that does not replicate in A. actinomycetemcomitans and carries a region with two inverted copies of a USS. This vector gave allelic exchange in the presence of cloned and induced tfoX easily and without digestion. Using transposon insertions in cloned katA DNA, we found that as little as 78 bp of homology at one of the ends was sufficient for that end to participate in allelic exchange. The cloning and induction of tfoX makes it possible to transform nearly any strain of A. actinomycetemcomitans, and allelic exchange has proven to be important for site-directed mutagenesis.

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Molecular Characterization of Low‐Molecular‐Weight Component Protein, Flp, in Actinobacillus actinomycetemcomitans Fimbriae

Cited by 79 publications

References 22 publications

Phylogeny of genes for secretion NTPases: Identification of the widespread tadA subfamily and development of a diagnostic key for gene classification

Phylogeny of genes for secretion NTPases: Identification of the widespread tadA subfamily and development of a diagnostic key for gene classification

Tight-adherence genes of Actinobacillus actinomycetemcomitans are required for virulence in a rat model

tfoX (sxy)-dependent transformation of Aggregatibacter (Actinobacillus) actinomycetemcomitans

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