3D correlative electron microscopy reveals continuity of Brucella-containing vacuoles with the endoplasmic reticulum.

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