Characterization of the Maf family of polymorphic toxins in pathogenic Neisseria species
Authors:Anne Jamet1,2,3,4,5, Xavier Nassif2,3,4,5
doi: 10.15698/mic2015.03.194
Volume 2, pp. 88 to 90, published 02/03/2015.
1 Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
2 Institut Necker Enfants-Malades, 14 rue Maria Helena Vieira Da Silva, CS 61431, 75014 Paris, France.
3 Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine, Paris, France.
4 INSERM, U1151, Paris, France.
5 CNRS UMR 8253, Paris, France.
Keywords:
Neisseria, MafB, toxin, immunity gene
Corresponding Author(s):
Conflict of interest statement:
The authors declare no competing financial interests.
Please cite this article as:
Anne Jamet, Xavier Nassif (2015). Characterization of the Maf family of polymorphic toxins in pathogenic Neisseria species. Microbial Cell 2(3): 88-90.
© 2015 Jamet and Nassif. This is an open-access article released under the terms of the Creative Commons Attribution (CC BY) license, which allows the unrestricted use, distribution, and reproduction in any medium, provid-ed the original author and source are acknowledged.
Abstract:
In addition to harmless commensal species, Neisseria genus encompasses two pathogenic species, N. meningitidis (the meningococcus) and N. gonorrhoeae (the gonococcus), which are responsible for meningitis and genital tract infections, respectively. Since the publication of the first Neisseria genome in 2000, the presence of several genomic islands (GI) comprising maf genes has been intriguing. These GIs account for approximately 2% of the genome of the pathogenic Neisseria species and the function of the proteins encoded by maf genes remained unknown. We showed that maf genes encode a functional toxin-immunity system where MafB is a toxin neutralized by an immunity protein named MafI. A strain can harbor several MafB/MafI modules with distinct toxic activities. MafB toxins are polymorphic toxins with a conserved N-terminal region and a variable C-terminal region. MafB N-terminal regions consist of a signal peptide and a domain named DUF1020 that is only found in the genus Neisseria. MafB C-terminal regions are highly polymorphic and encode toxic activities. We evidenced the presence of MafB in the culture supernatant of meningococcal cells and we observed a competitive advantage for a strain overexpressing a MafB toxin. Therefore, we characterized a highly variable family of toxin-immunity modules found in multiple loci in pathogenic Neisseria species.