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PLoS Pathog. 2015 Jan 8;11(1):e1004592. doi: 10.1371/journal.ppat.1004592. eCollection 2015 Jan.

A new family of secreted toxins in pathogenic Neisseria species.

Author information

1
Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France; Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine, Paris, France; Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France.
2
Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France.
3
Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France; Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine, Paris, France.

Abstract

The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation.

PMID:
25569427
PMCID:
PMC4287609
DOI:
10.1371/journal.ppat.1004592
[Indexed for MEDLINE]
Free PMC Article

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