Multiple large filament bundles observed in Caulobacter crescentus by electron cryotomography
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.
Additional Information
© 2006 The Authors. Journal compilation © 2006 Blackwell Publishing Ltd. Accepted 27 July, 2006. Article first published online: 29 Aug. 2006. The authors thank Christine Jacobs-Wagner for the crescentin knockout strains and discussions and L. Shapiro and Z. Gitai for discussions. This work was supported in part by NIH Grants P01 G66521 and R01 AI067548 to G.J.J., DOE Grant DE-FG02–04ER63785 to G.J.J., a Searle Scholar Award to G.J.J., a grant from the Danish Natural Sciences Research Council to R.B.J., and gifts to Caltech from the Ralph M. Parsons Foundation, the Agouron Institute, and the Gordon and Betty Moore Foundation.Attached Files
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Additional details
- Eprint ID
- 22359
- Resolver ID
- CaltechAUTHORS:20110217-125744917
- P01 G66521
- NIH
- R01 AI067548
- NIH
- DE-FG02–04ER63785
- Department of Energy (DOE)
- Danish Natural Sciences Research Council
- Ralph M. Parsons Foundation
- Agouron Institute
- Gordon and Betty Moore Foundation
- Searle Scholars Program
- Created
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2011-02-17Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field