Abstract
Polymerized tubulin can be stabilized in Kane's spindle isolation medium (HGL solution), isolated by differential centrifugation and then assayed by colchicine binding activity. In the eggs of the surf clam, Spisula solidissima, the level of particulate tubulin undergoes a series of specific changes during first meiotic division. In either unactivated ("interphase") eggs or metaphase eggs the amount of particulate tubulin was about 13% of the total at 23°C. The amount of particulate tubulin decreased shortly after activation, reaching a minimum value at about 5 min, the time of nuclear membrane breakdown. The particulate tubulin concentration then rose, reaching a maximum at metaphase, and then decreased again during anaphase, reaching a minimum at first polar body formation. In HGL homogenates of unactivated eggs a structure is present which has been shown to contain the interphase particulate tubulin (IPT). This structure consists essentially of a 10–20 µ granular sphere attached to a membranous material which is probably part of the egg cortex. These particles are absent at the time of nuclear membrane breakdown, when the level of particulate tubulin is minimal and when the first signs of spindle formation are visible. Electron microscopy of these particles by negative staining indicates that they are composed of microtubules associated with a granular matrix which may be a polymorphic aggregate of tubulin.
Full Text
The Full Text of this article is available as a PDF (1.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Borisy G. G., Taylor E. W. The mechanism of action of colchicine. Binding of colchincine-3H to cellular protein. J Cell Biol. 1967 Aug;34(2):525–533. doi: 10.1083/jcb.34.2.525. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brinkley B. R., Cartwright J., Jr Ultrastructural analysis of mitotic spindle elongation in mammalian cells in vitro. Direct microtubule counts. J Cell Biol. 1971 Aug;50(2):416–431. doi: 10.1083/jcb.50.2.416. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cohen W. D., Rebhun L. I. An estimate of the amount of microtubule protein in the isolated mitotic apparatus. J Cell Sci. 1970 Jan;6(1):159–176. doi: 10.1242/jcs.6.1.159. [DOI] [PubMed] [Google Scholar]
- Inoué S., Sato H. Cell motility by labile association of molecules. The nature of mitotic spindle fibers and their role in chromosome movement. J Gen Physiol. 1967 Jul;50(6 Suppl):259–292. [PMC free article] [PubMed] [Google Scholar]
- James K. A., Austin L. The binding in vitro of colchicine to axoplasmic proteins from chicken sciatic nerve. Biochem J. 1970 May;117(4):773–777. doi: 10.1042/bj1170773. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McIntosh J. R., Landis S. C. The distribution of spindle microtubules during mitosis in cultured human cells. J Cell Biol. 1971 May 1;49(2):468–497. doi: 10.1083/jcb.49.2.468. [DOI] [PMC free article] [PubMed] [Google Scholar]
- REBHUN L. I., SHARPLESS T. K. ISOLATION OF SPINDLES FROM THE SURF CLAM SPISULA SOLIDISSIMA. J Cell Biol. 1964 Aug;22:488–491. doi: 10.1083/jcb.22.2.488. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tilney L. G., Goddard J. Nucleated sites for the assembly of cytoplasmic microtubules in the ectodermal cells of blastulae of Arbacia punctulata. J Cell Biol. 1970 Sep;46(3):564–575. doi: 10.1083/jcb.46.3.564. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weisenberg R. C., Borisy G. G., Taylor E. W. The colchicine-binding protein of mammalian brain and its relation to microtubules. Biochemistry. 1968 Dec;7(12):4466–4479. doi: 10.1021/bi00852a043. [DOI] [PubMed] [Google Scholar]
- Winklmair D. A simple approach to the theory of cooperative aggregation of biological macromolecules. Arch Biochem Biophys. 1971 Dec;147(2):509–514. doi: 10.1016/0003-9861(71)90408-5. [DOI] [PubMed] [Google Scholar]