title: A new family of secreted toxins in pathogenic Neisseria species.
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.
authors.affiliation: 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.
authors.forename: Anne
authors.initials: A
authors.lastname: Jamet
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France.
authors.forename: Agnès B
authors.initials: AB
authors.lastname: Jousset
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France; Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine, Paris, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Euphrasie
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France.
authors.forename: Paulette
authors.initials: P
authors.lastname: Mukorako
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France.
authors.forename: Alix
authors.initials: A
authors.lastname: Boucharlat
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France.
authors.forename: Alexia
authors.initials: A
authors.lastname: Ducousso
authors.affiliation: Institut Necker Enfants-Malades, INSERM U1151, Equipe 11, Paris, France; Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Charbit
authors.affiliation: 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.
authors.forename: Xavier
authors.initials: X
authors.lastname: Nassif
mesh_terms: D000595:Amino Acid Sequence; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D005798:Genes, Bacterial; D044404:Genomic Islands / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D009343:Neisseria / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D030781:Organisms, Genetically Modified; D017434:Protein Structure, Tertiary; D055571:Secretory Pathway; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D037521:Virulence Factors