DprA is required for natural transformation and affects pilin variation in Neisseria gonorrhoeae

Abstract

Natural transformation is the main means of horizontal genetic exchange in the obligate human pathogen Neisseria gonorrhoeae and drives the spread of antibiotic resistance and virulence determinants. Transformation can be divided into four steps: (1) DNA binding, (2) DNA uptake, (3) DNA processing and (4) DNA recombination into the chromosome. The DNA processing enzyme DprA has been shown to shuttle incoming ssDNA to the recombination enzyme RecA during transformation in Bacillus subtilis and Streptococcus pneumoniae. Here, we investigate the role of DprA during transformation in N. gonorrhoeae. Inactivation of dprA completely abrogated transformation of gyrB1-encoding DNA, which confers nalidixic acid resistance. The presence of the DNA uptake sequence enhances DNA uptake and transformation by binding to the minor pilus protein ComP. Loss of transformation in the dprA null mutants was independent of the DNA uptake sequence. DprA mutants exhibited increased RecA-dependent pilin variation suggesting that DprA affects pilin variation. Unlike the exquisite UV sensitivity of a recA mutant, inactivation of dprA did not affect survival following UV irradiation. These results demonstrate that DprA has a conserved function during transformation, and reveal additional effects of DprA in N. gonorrhoeae during pilin variation.

Fine‐tuning cellular levels of DprA ensures transformant fitness in the human pathogen Streptococcus pneumoniae

“…In Bacillus subtilis, DprA also loads RecA onto transforming ssDNA (Yadav et al, 2013), although inactivation of dprA results in a more modest ~50-100-fold loss of transformation efficiency (Yadav et al, 2012). DprA also plays a role in transformation, presumably as a RMP, in Haemophilus influenzae (Karudapuram et al, 1995), Neisseria gonorrhoeae (Duffin and Barber, 2016), Neisseria meningitidis (Hovland et al, 2017) Campylobacter jejuni (Takata et al, 2005), and Helicobacter pylori (Ando et al, 1999;Smeets et al, 2000). Although the mechanism of transformation remains broadly conserved across transformable bacteria, the regulation of competence is very diverse (Johnston et al, 2014).…”

Comparative proteomic analysis of Neisseria meningitidis wildtype and dprA null mutant strains links DNA processing to pilus biogenesis

“…DprA in bacteria is so far shown to be required for competence for DNA transformation [4] and suggested to be involved in RecA-mediated pilin variation [19]. The presence of a dprA gene has been suggested to be a distinctive feature of naturally transformable species [27].…”

“…Using a transposon mutant screen in Nm, Tang and co-workers showed that the dprA null mutant exhibits total loss of competence for DNA transformation [4]. The Nm and Ng dprA null mutants are non-transformable regardless of the type of donor DNA substrate, and Ng DprA is suggested to be involved in RecA-mediated pilin variation [4, 19]. HGT in Haemophilus influenzae, S. pneumoniae , and B. subtilis is associated with DprA [8, 15, 20, 21].…”

Pull in and Push Out: Mechanisms of Horizontal Gene Transfer in Bacteria

“…The driving force for translocation of ssDNA across the IM may be provided by an ATPase (ComFA), which is also widely conserved in bacteria ( Londono-Vallejo and Dubnau, 1994 ; Takeno et al, 2011 ; Chilton et al, 2017 ; Diallo et al, 2017 ). After translocation of ssDNA, DprA, and RecA bind ssDNA and catalyze the formation of joint DNA molecules for homologous recombination ( Mortier-Barriere et al, 2007 ; Dwivedi et al, 2013 ; Yadav et al, 2013 , 2014 ; Duffin and Barber, 2016 ; Diallo et al, 2017 ; Hovland et al, 2017 ; Le et al, 2017 ). In this way, the incoming foreign ssDNA displaces one strand of the chromosomal dsDNA ( Mortier-Barriere et al, 2007 ), followed by being converted to homogeneous dsDNA through DNA replication.…”