A New Family of Secreted Toxins in Pathogenic Neisseria Species

PLoS Pathogens

Xavier Nassif¹  Daniel Euphrasie¹  Paulette Mukorako²  Alix Boucharlat³  Anne Jamet³  Alexia Ducousso³  Alain Charbit⁴  Agnès B. Jousset⁴ 

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

关键词: Toxins;    Sequence motif analysis;    Neisseria meningitidis;    Neisseria;    Secretion systems;    Immunity;    Neisseria gonorrhoeae;    Genetic loci;   

DOI  :  10.1371/journal.ppat.1004592

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY