Concerted spatio-temporal dynamics of imported DNA and ComE DNA uptake protein during gonococcal transformation

PLoS Pathog. 2014 Apr 24;10(4):e1004043. doi: 10.1371/journal.ppat.1004043. eCollection 2014 Apr.

Abstract

Competence for transformation is widespread among bacterial species. In the case of Gram-negative systems, a key step to transformation is the import of DNA across the outer membrane. Although multiple factors are known to affect DNA transport, little is known about the dynamics of DNA import. Here, we characterized the spatio-temporal dynamics of DNA import into the periplasm of Neisseria gonorrhoeae. DNA was imported into the periplasm at random locations around the cell contour. Subsequently, it was recruited at the septum of diplococci at a time scale that increased with DNA length. We found using fluorescent DNA that the periplasm was saturable within minutes with ∼40 kbp DNA. The DNA-binding protein ComE quantitatively governed the carrying capacity of the periplasm in a gene-dosage-dependent fashion. As seen using a fluorescent-tagged derivative protein, ComE was homogeneously distributed in the periplasm in the absence of external DNA. Upon addition of external DNA, ComE was relocalized to form discrete foci colocalized with imported DNA. We conclude that the periplasm can act as a considerable reservoir for imported DNA with ComE governing the amount of DNA stored potentially for transport through the inner membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biological Transport, Active / physiology
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Neisseria gonorrhoeae / genetics
  • Neisseria gonorrhoeae / metabolism*
  • Periplasm / genetics
  • Periplasm / metabolism*
  • Transformation, Bacterial / physiology*

Substances

  • Bacterial Proteins
  • ComE protein, Neisseria gonorrhoeae
  • DNA, Bacterial
  • DNA-Binding Proteins

Grants and funding

HG, CH, SM, and BM were supported by the Deutsche Forschungsgemeinschaft through grants MA3898. The work of MK and FEA was supported in part by Research Council of Norway grants 183613 and 183814 and by funds from the Center for Molecular Biology and Neurosciences of the University of Oslo. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.