Multiple large filament bundles observed in Caulobacter crescentus by electron cryotomography.

A Briegel, DP Dias, Z Li, Rasmus Bugge Jensen, AS Frangakis, GJ Jensen

    Publikation: Bidrag til tidsskriftTidsskriftartikelpeer review

    Abstract

    While the absence of any cytoskeleton was once recognized as a distinguishing feature of prokaryotes, it is now clear that a number of different bacterial proteins do form filaments in vivo. Despite the critical roles these proteins play in cell shape, genome segregation and cell division, molecular mechanisms have remained obscure in part for lack of electron microscopy-resolution images where these filaments can be seen acting within their cellular context. Here, electron cryotomography was used to image the widely studied model prokaryote Caulobacter crescentus in an intact, near-native state, producing three-dimensional reconstructions of these cells with unprecedented clarity and fidelity. We observed many instances of large filament bundles in various locations throughout the cell and at different stages of the cell cycle. The bundles appear to fall into four major classes based on shape and location, referred to here as 'inner curvature', 'cytoplasmic', 'polar' and 'ring-like'. In an attempt to identify at least some of the filaments, we imaged cells where crescentin and MreB filaments would not be present. The inner curvature and cytoplasmic bundles persisted, which together with their localization patterns, suggest that they are composed of as-yet unidentified cytoskeletal proteins. Thus bacterial filaments are frequently found as bundles, and their variety and abundance is greater than previously suspected.
    OriginalsprogEngelsk
    TidsskriftMolecular Microbiology
    Vol/bind62
    Udgave nummer1
    Sider (fra-til)5-14
    Antal sider9
    ISSN0950-382X
    StatusUdgivet - 2006

    Citer dette