The role of transformation in the variability of the <i>Neisseria gonorrhoeae</i> cell surface

Scocca, John J.

doi:10.1111/j.1365-2958.1990.tb00599.x

Cited by 12 publications

(7 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the requirement for RecA in the antigenic and phase variation of gonococcal pilin is firmly established, the possibility that a site-specific recombinase might also play a role has been suggested previously (23,37,38,48). The fact that Piv is involved in type 4 pilin variation of M. lacunata and M. bovis led to our hypothesis that a Piv-like recombinase may exist in N. gonorrhoeae, although it would not necessarily be involved in pilin variation.…”

Section: Discussionmentioning

confidence: 85%

Inversion of Moraxella lacunata type 4 pilin gene sequences by a Neisseria gonorrhoeae site-specific recombinase

1997

View full text Add to dashboard Cite

A plasmid library of Neisseria gonorrhoeae sequences was screened for the ability to mediate recombinations on a sequence containing the Moraxella lacunata type 4 pilin gene invertible region in Escherichia coli. A plasmid containing the N. gonorrhoeae sequence encoding the putative recombinase (gcr) was identified and sequenced. Plasmids containing gcr were able to mediate site-specific recombinations despite a weak amino acid homology to Piv, the native M. lacunata pilin gene invertase. The gcr gene is present only in pathogenic strains of Neisseria tested; however, in our assays gene knockouts of gcr did not alter the variation of surface features that play a role in the pathogenesis of N. gonorrhoeae.The Piv recombinase is the only Moraxella gene product required to mediate inversion of the cloned Moraxella lacunata and Moraxella bovis type 4 pilin gene regions in Escherichia coli (25,28). The stop codons for two partial 3Ј pilin domains (tfpQ and tfpI) lie within a 2.1-kb invertible region, while the short, conserved 5Ј domain and pilin promoter lie just outside this segment (27,28). Site-specific recombinations between the boundaries of the invertible region result in transcriptional fusions of the tfpQ or tfpI domain to the conserved 5Ј pilin domain and promoter (27,31). These inversions are clearly demonstrated by use of restriction sites located asymmetrically in the invertible region and by the different mobilities of pilin subunits produced in E. coli by immunoblot analysis (31). Further highlighting the essential role for Piv in site-specific recombination, insertions into or deletions in the M. lacunata piv gene eliminate inversion of the pilin gene segment (28). Inversions of these phase-locked constructs can be restored by a plasmid carrying the piv gene (28).The type 4 pili produced by M. lacunata and M. bovis are also produced by a variety of gram-negative mammalian pathogens, including Neisseria gonorrhoeae (19,42). Pili are generally thought to play an important role in the establishment of infection by mediating the attachment to host epithelial cells and are also associated with competence for DNA transformation (4, 40), twitching motility (18), and autoagglutination (44). The gonococcal genome is well known for its ability to alter the pilin structural gene by recombination of silent pilin sequences (pilS) into the expression locus (pilE) (6,16,17,26,45). Deletions in the recA allele decrease antigenic variation of the pilin gene 100-to 1,000-fold (23), yet homologies between recombining sequences are as low as 30 bp (29), leaving open the possibility that a site-specific recombinase or other locusspecific factor facilitates the recombination process. Interestingly, there is no evidence of site-specific recombinases, phage, transposons, or insertion sequences characterized in the gonococcal genome despite this well-documented genomic plasticity. We hypothesized that if a site-specific recombinase exists in gonococci, it may be able to mediate inversions on the cloned M. lacunata type 4 pili...

show abstract

Section: Discussionmentioning

confidence: 85%

Inversion of Moraxella lacunata type 4 pilin gene sequences by a Neisseria gonorrhoeae site-specific recombinase

1997

View full text Add to dashboard Cite

show abstract

“…However, additional roles for genetic competence have been hypothesized, such as a nutrition and a sensory function for the initiation of an SOS-like response (29). We anticipate that the future assessment of genetic competence will generate insights into the evolutionary and physiological principles associated with naturally competent microorganisms, many of which are pathogens.…”

Section: Discussionmentioning

confidence: 99%

Role of pili and the phase-variable PilC protein in natural competence for transformation of Neisseria gonorrhoeae.

Rudel

Facius

Barten

et al. 1995

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

109

View full text Add to dashboard Cite

The Gram-negative bacterial pathogen Neisseria gonorrhoeae is naturally competent for transformation with species-related DNA. We show here that two phasevariable pilus-associated proteins, the major pilus subunit (pilin, or PilE) and PilC, a factor known to function in the assembly and adherence of gonococcal pili, are essential for transformation competence. The PilE and PilC proteins are necessary for the conversion of linearized plasmid DNA carrying the Neisseria-specific DNA uptake signal into a DNase-resistant form. The biogenesis of typical pilus fibers is neither essential nor sufficient for this process. DNA uptake deficiency of defined piliated pilCI,2 double mutants can be complemented by expression of a cloned pilC2 gene in trans. The PilC defect can also be restored by the addition ofpurified PilC protein, or better, pili containing PilC protein, to the mutant gonococci. Our data suggest that the two phasevariable Pil proteins act on the bacterial cell surface and cooperate in DNA recognition and/or outer membrane translocation.Neisseria gonorrhoeae, a strictly human-specific Gram-negative bacterial pathogen, belongs to a group of microorganisms that are naturally competent for DNA transformation (1). Natural transformation competence is considered to play a role in the horizontal exchange of genetic information between species, aside from transduction and conjugation (2, 3). DNA transformation appears to be particularly relevant in the case of N. gonorrhoeae, which, based on current knowledge, is not infected by any transducing phage (or phage in general) and is devoid of genetic elements capable of mobilizing chromosomal determinants. Thus, transformation is the mechanism that most probably accounts for the evolutionary signs of horizontal exchange in N. gonorrhoeae and related species (3-9).Transforming DNA is linearized during the uptake by N. gonorrhoeae (10). Rescue of linear plasmid DNA or chromosomal segments requires both a functional RecA protein and sufficient homology in the resident DNA pool; transformation is therefore limited to species-related DNA. Another restricting factor for species-related DNA is a specific nucleotide sequence required for the uptake of DNA (11,12) MATERIALS AND METHODSConstruction of Strains and Plasmids. All gonococcal strains used in this study are derived from N. gonorrhoeae MS11 (ref. 23; see Table 1). Plasmid pHEMK40 carrying the induciblepilEF3 gene (20) and pHTR93 encoding PilC (see Fig. 1) are derivatives of the conjugative N. gonorrhoeae plasmid ptetM25.2 constructed by gene replacement using the Hermes shuttle system (13,20). Gene replacements in the gonococcal genome or ptetM25.2 were carried out via transformation selected for in the presence of erythromycin (7 ,ug/ml for ermC) or chloramphenicol (Cm; 6, 12, or 20 pLg/ml for catLow, standard, or secondary catGC mutations, respectively). The conjugation of ptetM25.2 derivatives has been described (20). E. coli plasmid pES3 is plasmid pIP100 (4) with the ermC determinant inserted into the Bg...

show abstract

“…It is also interesting to speculate that natural transformation may play a critical role in antigenic variability similar to what has been observed in Neisseria spp. (50,51).…”

Section: Discussionmentioning

confidence: 99%

Variation in antigenicity and molecular weight of Campylobacter coli VC167 flagellin in different genetic backgrounds

et al. 1992

View full text Add to dashboard Cite

Campylobacter coli VC167 has been shown to undergo a reversible flagellar antigenic variation between antigenic type 1 (T1) and antigenic type 2 (T2). VC167 contains two flagellin genes, and the products of both genes are incorporated into a complex flagellar filament in both antigenic types. Although there are only minor amino acid changes in the flagellins expressed by Ti and T2 cells, the two antigenic types of flagellins can be distinguished by differences in apparent Mr on sodium dodecyl sulfate-polyacrylamide gels and by immunoreactivity with Ti-specific (LAHI1) or T2-specific (LAH2) antiserum. The isolation of stable variants of Ti and T2 has allowed for the transfer via natural transformation of the flagellin structural genes from the Ti background into the T2 background and from the T2 background into the Ti background. In addition, the

show abstract

The role of transformation in the variability of the Neisseria gonorrhoeae cell surface

Cited by 12 publications

References 35 publications

Inversion of Moraxella lacunata type 4 pilin gene sequences by a Neisseria gonorrhoeae site-specific recombinase

Inversion of Moraxella lacunata type 4 pilin gene sequences by a Neisseria gonorrhoeae site-specific recombinase

Role of pili and the phase-variable PilC protein in natural competence for transformation of Neisseria gonorrhoeae.

Variation in antigenicity and molecular weight of Campylobacter coli VC167 flagellin in different genetic backgrounds

Contact Info

Product

Resources

About