Minisymposium 6: Cytoskeleton
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Abs #
M0603: High Resolution SEM of Plant Microtubules: FESEM Finds a MAP
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Presenter: |
Barton, Deborah A. Contact Presenter |
Authors | Barton, Deborah A. (A) Vantard, Marylin (B) Overall, Robyn L. (A) | | Affiliations: |
(A): University of Sydney, School of Biological Sciences
(B): Universite Joseph Fourier de Grenoble, Departement Reponse et Dynamique Cellulaires
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During interphase in plant cells, microtubules form an array that extends over the inner surface of the plasma membrane. We imaged these arrays within elongating Tradescantia virginiana leaf epidermal peels, Arabidopsis thaliana roots and Tobacco BY2 membrane ghosts using field emission scanning electron microscopy (FESEM). In each cell type, individual microtubules appeared as long, thin filaments, 25 nm in diameter, lying adjacent to the plasma membrane. We investigated the dynamics, structure and organisation of interphase arrays within T. virginiana cells and found that these were composed to two major subpopulations. Microtubules that lay adjacent to the plasma membrane were usually bundled, coaligned and were the more stable subpopulation. The second subpopulation contained more labile, randomly oriented microtubules that lay deeper into the cytoplasm. These subpopulations were not characterised by their tyrosinated or detyrosinated states. Interactions between individual microtubules resulted in bundling if they met at angles under 20o or in crossovers if at angles greater than 20o. Crossbridges were seen between bundled microtubules, but not necessarily along their entire lengths. A variety of microtubule end morphologies were observed, ranging from blunt, to pointed, and flared ends. An antibody against the microtubule severing protein katanin localised to microtubule ends, curves, and on occasion, to fine bands that crossed microtubule widths. An antibody against the plus end binding protein, AtEB1c localised to microtubule ends, lengths, junctions between microtubules, and occasionally on the plasma membrane in line with a microtubule end. We show that FESEM is a powerful tool to investigate the interactions between microtubules and their associated proteins.
