Open AccessEssential role of the VirB machinery in the maturation of the Brucella abortus ‐containing vacuole
Author(s) -
Comerci Diego J.,
MartínezLorenzo Maria José,
Sieira Rodrigo,
Gorvel JeanPierre,
Ugalde Rodolfo A.
Publication year - 2001
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1046/j.1462-5822.2001.00102.x
Subject(s) - vacuole , biology , endocytic cycle , microbiology and biotechnology , endoplasmic reticulum , intracellular , brucella , secretory pathway , intracellular parasite , mutant , phagosome , secretion , biogenesis , gene , cell , genetics , biochemistry , cytoplasm , endocytosis , golgi apparatus , virology , brucellosis
In epithelial cells, the intracellular pathogen Brucella abortus escapes from the endocytic pathway, exploits the autophagic machinery of the host cell and establishes a unique replication niche in the endoplasmic reticulum. The molecular mechanisms underlying these processes are still poorly understood. Recently, a B. abortus type IV‐related secretion system encoded by the virB operon has been described as being involved in the intracellular trafficking of the bacteria. In this study, we have analysed the intracellular pathway of B. abortus virB10 mutant strains by confocal microscopy. We demonstrate that a functional virB operon is essential for the biogenesis of the Brucella ‐containing vacuole. Polar mutation preventing the transcription of virB10 and downstream sequences did not allow Brucella to bypass the endocytic pathway. Consequently, polar mutant‐containing vacuoles fused with lysosomes in which bacteria underwent a degradation process. In contrast, virB10 non‐polar mutants were capable of avoiding interactions with the endocytic pathway but, diverging to wild‐type Brucella , were unable to reach the endoplasmic reticulum to establish their intracellular replication niche and seemed to be recycled to the cell surface. Based on the two particular phenotypes described in this work, a model of maturation of the Brucella‐ containing vacuole is proposed.