Abstract
THE microtubule cytoskeleton of animal cells does not assemble spontaneously, but instead requires the centrosome. This organelle consists of a pair of centrioles surrounded by a complex collection of proteins known as the pericentriolar material (PCM)1. The PCM is required for microtubule nucleation2. The minus, or slow-growing, ends of microtubules are embedded in the PCM and the plus, or fast-growing, ends project outwards into the cytoplasm during interphase, or into the spindle apparatus during mitosis, γ-Tubulin is the only component of the PCM that is so far implicated in microtubule nucleation3–6. Here we use immuno-electron microscopic tomography to show that γ-tubulin is localized in ring structures in the PCM of purified centrosomes without microtubules. When these centrosomes are used to nucleate microtubule growth, γ-tubulin is localized at the minus ends of the microtubules. We conclude that microtubule-nucleating sites within the PCM are ring-shaped templates that contain multiple copies of γ-tubulin.
Similar content being viewed by others
Article PDF
References
Kellogg, D. R., Moritz, M. & Alberts, B. M. A. Rev. Biochem. 63, 639–674 (1994).
Gould, R. R. & Borisy, G. G. J. Cell Biol. 73, 601–615 (1977).
Oakley, B. R. Trends Cell Biol. 2, 1–5 (1992).
Joshi, H. C., Palacios, M. J., McNamara, L. & Cleveland, D. W. Nature 356, 80–83 (1992).
Felix, M.-A., Antony, C., Wright, M. & Maro, B. J. Cell Biol. 124, 19–31 (1994).
Stearns, T. & Kirschner, M. Cell 76, 623–637 (1994).
Moritz, M. et al. J. Cell Biol. 130, 1149–1159 (1995).
Koster, A. J., Chen, H., Sedat, J. W. & Agard, D. A. Ultramicroscopy 46, 207–227 (1992).
Koster, A. J. et al. Microsc. Soc. Am. Bull. 23, 176–188 (1993).
Tilney, L. G. et al. J. Cell Biol. 59, 267–275 (1973).
Evans, L., Mitchison, T. & Kirschner, M. J. Cell Biol. 100, 1185–1191 (1985).
Zheng, Y., Wong, M. L., Alberts, B. & Mitchison, T. Nature 378, 578–583 (1995).
Fung, J. C. et al. J. struct. Biol. (in the press).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Moritz, M., Braunfeld, M., Sedat, J. et al. Microtubule nucleation by γ-tubulin-containing rings in the centrosome. Nature 378, 638–640 (1995). https://doi.org/10.1038/378638a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/378638a0
