Mobile DNA in the Pathogenic Neisseria

Abstract

The genus Neisseria contains two pathogenic species of notable public health concern: Neisseria gonorrhoeae and Neisseria meningitidis. These pathogens display a notable ability to undergo frequent programmed recombination events. The recombination mediated pathways of transformation and pilin antigenic variation in the Neisseria are well studied systems that are critical for pathogenesis. Here we will detail the conserved and unique aspects of transformation and antigenic variation in the Neisseria. Transformation will be followed from initial DNA binding through recombination into the genome with consideration to the factors necessary at each step. Additional focus is paid to the unique type IV secretion system that mediates donation of transforming DNA in the pathogenic Neisseria. The pilin antigenic variation system uses programed recombinations to alter a major surface determinant which allows immune avoidance and promotes infection. We discuss the trans- and cis- acting factors which facilitate pilin antigenic variation and present the current understanding of the mechanisms involved in the process.

The effect of recombination on the evolution of a population ofNeisseria meningitidis

“…Though recombination rate is doubtlessly affected by many factors, this does suggest that there are lineage-specific genetic components affecting the rate of recombination in N. meningitidis. Though there exists an understanding of the mechanisms that underlie recombination in N. meningitidis (Obergfell and Seifert, 2015), knowledge of how these and other genetic factors that affect the rate of recombination differ between lineages has not yet been fully explored. This awareness would not only be important to our understanding of the evolution of N. meningitidis and other Neisseria, but it would also allow for a more detailed monitoring of the populations of these serious human pathogens.…”

“…other (Obergfell and Seifert, 2015). Various mechanisms of recombination have been described in N. meningitidis (Joseph et al, 2011;Marri et al, 2010;Schoen et al, 2009), involving abundant and diverse repetitive DNA sequences in its chromosome.…”

Changing of the guard: How the Lyme disease spirochete subverts the host immune response

“…Although these regions can certainly form intermolecular G-quadruplex in vitro, whether such structures form in vivo and whether they influence recombinational switching or other functions is not currently known. Although G4 DNA is an important feature in recombinational switching at Neisseria pilE (5), that situation involves the formation of a specific intramolecular G-quadruplex that serves as a site for DNA nicking. The G4 structure is believed to be processed by the RecQ helicase (59), which is absent from B. burgdorferi.…”

“…Antigenic variation is a common pathogenic ruse employed by several bacterial, protozoan, and fungal pathogens (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). This process involves changes in a prominent surface antigen such that it is no longer recognized by the host acquired immune response ( Fig.…”

A Borrelia burgdorferi mini‐vls system that undergoes antigenic switching in mice: investigation of the role of plasmid topology and the long inverted repeat

“…The vls loci of all B. burgdorferi strains analyzed also contain G-runs on the coding strand, with the possibility of a role for G-quadruplexes in the switching reaction (Walia and Chaconas, 2013). A G-quartet has been shown to play a role in recombinatonal switching at the pilE locus in Neisseria species (Obergfell and Seifert, 2015). The presence of some of these elements and perhaps other yet to be identified DNA have limited cloning of the vls locus on plasmids in Escherichia coli.…”