Oakley B R, Akkari Y N
Department of Molecular Genetics, The Ohio State University, 484 W. 12th Ave., Columbus, OH 43210, USA.
Cell Struct Funct. 1999 Oct;24(5):365-72. doi: 10.1247/csf.24.365.
The existence of gamma-tubulin was first reported approximately ten years ago, and it is appropriate to review the progress that has been made in gamma-tubulin research and to discuss some of the unanswered questions about gamma-tubulin function. gamma-Tubulin is ubiquitous in eukaryotes and is generally quite conserved. Two highly divergent gamma-tubulins have been discovered, however, one in Saccharomyces cerevisiae and one in Caenorhabditis elegans. Several organisms have two gamma-tubulin genes. In Drosophila melanogaster, the two gamma-tubulins differ significantly in sequence and expression pattern. In other organisms the two gamma-tubulins are almost identical and expression patterns have not been determined. gamma-Tubulin is located at microtubule organizing centers in many organisms, and it is also frequently associated with the mitotic spindle. gamma-Tubulin is essential for the formation of functional mitotic spindles in all organisms that have been examined to date. In animal cells, complexes containing gamma-tubulin are located at microtubule organizing centers where they nucleate the assembly of microtubules. In spite of the considerable progress that has been made in gamma-tubulin research important questions remain to be answered. The exact mechanisms of microtubule nucleation by gamma-tubulin complexes remain to be resolved as do the mechanisms by which microtubule nucleation from gamma-tubulin complexes is regulated. Finally, there is evidence that gamma-tubulin has important functions in addition to microtubule nucleation, and these functions are just beginning to be investigated.
γ-微管蛋白的存在大约在十年前首次被报道，现在是时候回顾一下γ-微管蛋白研究取得的进展，并讨论一些关于γ-微管蛋白功能尚未解答的问题了。γ-微管蛋白在真核生物中普遍存在，并且通常相当保守。然而，已经发现了两种高度不同的γ-微管蛋白，一种存在于酿酒酵母中，另一种存在于秀丽隐杆线虫中。几种生物有两个γ-微管蛋白基因。在黑腹果蝇中，这两种γ-微管蛋白在序列和表达模式上有显著差异。在其他生物中，这两种γ-微管蛋白几乎相同，其表达模式尚未确定。γ-微管蛋白在许多生物中位于微管组织中心，并且它也经常与有丝分裂纺锤体相关。在迄今已研究的所有生物中，γ-微管蛋白对于功能性有丝分裂纺锤体的形成都是必不可少的。在动物细胞中，含有γ-微管蛋白的复合物位于微管组织中心，在那里它们启动微管的组装。尽管γ-微管蛋白研究已经取得了相当大的进展，但重要的问题仍有待解答。γ-微管蛋白复合物启动微管形成的确切机制以及γ-微管蛋白复合物启动微管形成的调控机制都有待解决。最后，有证据表明γ-微管蛋白除了启动微管形成外还有重要功能，而这些功能才刚刚开始被研究。
