the bacterial cytoskeleton modulates motility, type 3 secretion, and colonization in salmonella细菌细胞骨架调节能动性,3型分泌,沙门氏菌和殖民.pdf

The Bacterial Cytoskeleton Modulates Motility, Type 3 Secretion, and Colonization in Salmonella 1 1 2 1 2 David M. Bulmer , Lubna Kharraz , Andrew J. Grant , Paul Dean , Fiona J. E. Morgan , Michail H. 1 1 3 3 1 2 Karavolos , Anne C. Doble , Emma J. McGhie , Vassilis Koronakis , Richard A. Daniel , Pietro Mastroeni , C. M. Anjam Khan1* 1 Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Newcastle, United Kingdom, 2 Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom, 3 Department of Pathology, University of Cambridge, Cambridge, United Kingdom Abstract Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable DmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS) and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validat