A Fratricidal Mechanism Is Responsible for eDNA Release and Contributes to Biofilm Development of Enterococcus Faecalis

Mol Microbiol. 2009 May;72(4):1022-36. doi: 10.1111/j.1365-2958.2009.06703.x. Epub 2009 Apr 21.

Abstract

Extracellular DNA (eDNA), a by-product of cell lysis, was recently established as a critical structural component of the Enterococcus faecalis biofilm matrix. Here, we describe fratricide as the governing principle behind gelatinase (GelE)-mediated cell death and eDNA release. GFP reporter assays confirmed that GBAP (gelatinase biosynthesis-activating pheromone) quorum non-responders (GelE-SprE-) were a minority subpopulation of prey cells susceptible to the targeted fratricidal action of the quorum responsive predatorial majority (GelE+SprE+). The killing action is dependent on GelE, and the GelE producer population is protected from self-destruction by the co-production of SprE as an immunity protein. Targeted gene inactivation and protein interaction studies demonstrate that extracellular proteases execute their characteristic effects following downstream interactions with the primary autolysin, AtlA. Finally, we address a mechanism by which GelE and SprE may modify the cell wall affinity of proteolytically processed AtlA resulting in either a pro- or anti-lytic outcome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacteriolysis
  • Biofilms / growth & development*
  • DNA, Bacterial / metabolism*
  • Enterococcus faecalis / genetics
  • Enterococcus faecalis / growth & development*
  • Enterococcus faecalis / metabolism
  • Gelatinases / metabolism
  • Lactones / metabolism
  • Mutagenesis, Insertional
  • N-Acetylmuramoyl-L-alanine Amidase / metabolism
  • Peptides, Cyclic / genetics
  • Peptides, Cyclic / metabolism
  • Serine Endopeptidases / metabolism

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • Lactones
  • Peptides, Cyclic
  • gelatinase biosynthesis-activating pheromone
  • Serine Endopeptidases
  • Gelatinases
  • N-Acetylmuramoyl-L-alanine Amidase