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A ubiquitous mobile genetic element changes the antagonistic weaponry of a human gut symbiont

Affiliations
  • 1Duchossois Family Institute, University of Chicago, Chicago, IL, USA.
  • 2Department of Microbiology, University of Chicago, Chicago, IL, USA.
  • 3Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA.
  • 4National Food Institute, Technical University of Denmark, Lyngby, Denmark.
  • 5Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA.
  • 6Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, USA.
  • 7Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.

Published on:

October 24, 2024

Abstract

DNA transfer is ubiquitous in the human gut microbiota, especially among species of the order Bacteroidales. In silico analyses have revealed hundreds of mobile genetic elements shared between these species, yet little is known about the phenotypes they encode, their effects on fitness, or pleiotropic consequences for the recipient’s genome. In this work, we show that acquisition of a ubiquitous integrative conjugative element (ICE) encoding a type VI secretion system (T6SS) shuts down the native T6SS of . Despite inactivating this T6SS, ICE acquisition increases the fitness of the transconjugant over its progenitor by arming it with the new T6SS. DNA transfer causes the strain to change allegiances so that it no longer targets ecosystem members with the same element yet is armed for communal defense.

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