3D correlative electron microscopy reveals continuity of Brucellacontaining vacuoles with the endoplasmic reticulum

Jaroslaw Sedzicki, Therese Tschon, Shyan Huey Low, Kevin Willemart, Kenneth N Goldie, Jean-Jacques Letesson, Henning Stahlberg, Christoph Dehio

Research output: Contribution to journalArticle

Abstract

Entry of the facultative intracellular pathogenBrucellainto host cells results in the formation of endosomalBrucella-containing vacuoles (eBCVs) that initially traffic along the endocytic pathway. eBCV acidification triggers the expression of a type IV secretion system that translocates bacterial effector proteins into host cells. This interferes with lysosomal fusion of eBCVs and supports their maturation to replicativeBrucella-containing vacuoles (rBCVs). Bacteria replicate in rBCVs to large numbers, eventually occupying most of the cytoplasmic volume. As rBCV membranes tightly wrap each individual bacterium, they are constantly being expanded and remodeled during exponential bacterial growth. rBCVs are known to carry endoplasmic reticulum (ER) markers; however, the relationship of the vacuole to the genuine ER has remained elusive. Here, we have reconstructed the 3-dimensional ultrastructure of rBCVs and associated ER by correlative structured illumination microscopy (SIM) and focused ion beam/scanning electron microscopic tomography (FIB/SEM). StudyingB. abortus-infected HeLa cells and trophoblasts derived fromB. melitensis-infected mice, we demonstrate that rBCVs are complex and interconnected compartments that are continuous with neighboring ER cisternae, thus supporting a model that rBCVs are extensions of genuine ER.

Original languageEnglish
Article numberjcs210799
JournalJournal of Cell Science
Volume131
Issue number4
DOIs
Publication statusPublished - 1 Feb 2018
Externally publishedYes

    Fingerprint

Keywords

  • CLEM
  • Correlative light and electron microscopy
  • Endoplasmic reticulum
  • FIB/SEM tomography
  • RBCV
  • Replicative Brucellacontaining vacuole
  • Sec61
  • Brucella melitensis/pathogenicity
  • Microscopy, Electron, Scanning
  • Type IV Secretion Systems/ultrastructure
  • Humans
  • Vacuoles/microbiology
  • Brucella abortus/pathogenicity
  • Animals
  • Trophoblasts/microbiology
  • Cytoplasm/microbiology
  • Host-Pathogen Interactions/genetics
  • Endoplasmic Reticulum/microbiology
  • Mice
  • HeLa Cells

Cite this