Analysis of Tub4p, a yeast gamma-tubulin-like protein: implications for microtubule-organizing center function
| Autor: | Robert L. Jeng, Tim Stearns, Jon Mulholland, Laura G. Marschall |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1996 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Genes Fungal Molecular Sequence Data Saccharomyces cerevisiae Spindle Apparatus Microtubules Spindle pole body Tubulin Animals DNA Fungal Microtubule nucleation Tubulin complex biology Base Sequence Kinetochore Microtubule organizing center Cell Biology Articles Cell biology Spindle apparatus Spindle checkpoint Phenotype Mutation biology.protein Rabbits |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| Popis: | gamma-Tubulin is a conserved component of microtubule-organizing centers and is thought to be involved in microtubule nucleation. A recently discovered Saccharomyces cerevisiae gene (TUB4) encodes a tubulin that is related to, but divergent from, gamma-tubulins. TUB4 is essential for cell viability, and epitope-tagged Tub4 protein (Tub4p) is localized to the spindle pole body (Sobel, S.G., and M. Snyder. 1995.J. Cell Biol. 131:1775-1788). We have characterized the expression of TUB4, the association of Tub4p with the spindle pole body, and its role in microtubule organization. Tub4p is a minor protein in the cell, and expression of TUB4 is regulated in a cell cycle-dependent manner. Wild-type Tub4p is localized to the spindle pole body, and a Tub4p-green fluorescent protein fusion is able to associate with a preexisting spindle pole body, suggesting that there is dynamic exchange between cytoplasmic and spindle pole body forms of Tub4p. Perturbation of Tub4p function, either by conditional mutation or by depletion of the protein, results in spindle as well as spindle pole body defects, but does not eliminate the ability of microtubules to regrow from, or remain attached to, the spindle pole body. The spindle pole bodies in tub4 mutant cells duplicate but do not separate, resulting in a monopolar spindle. EM revealed that one spindle pole body of the duplicated pair appears to be defective for the nucleation of microtubules. These results offer insight into the role of gamma-tubulin in microtubule-organizing center function. |
| Databáze: | OpenAIRE |
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