Horio T, Uzawa S, Jung M K, Oakley B R, Tanaka K, Yanagida M
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
J Cell Sci. 1991 Aug;99 ( Pt 4):693-700. doi: 10.1242/jcs.99.4.693.
gamma-Tubulin exists in fission yeast as the product of an essential gene, encoding a 446 amino acid protein that is 77.3% identical to Aspergillus nidulans gamma-tubulin. The gene disruption caused cell lethality, displaying condensed, undivided chromosomes with aberrant spindle structures. Anti-gamma-tubulin staining showed that gamma-tubulin is located, throughout the wild-type cell cycle, at the spindle pole bodies (SPBs), indicating that gamma-tubulin associates with interphase SPB in the absence of microtubules. In addition, anti-gamma-tubulin immunofluorescence staining revealed cytoplasmic, cell-equatorial putative MTOCs (microtubule organizing centers), which appear only during mitotic telophase and cytokinesis, and are located at the centers for the new cytoplasmic microtubule arrays of the two daughter cells. In the multiple-SPB mutant cut1-cdc11, anti-gamma-tubulin antibodies revealed many dots on the periphery of the nucleus. These results confirm that gamma-tubulin is an important member of the tubulin superfamily, suggest that it may be a universal component of MTOCs, and are consistent with a role for gamma-tubulin in controlling microtubule formation in vivo.
γ-微管蛋白在裂殖酵母中作为一个必需基因的产物存在,该基因编码一种446个氨基酸的蛋白质,与构巢曲霉的γ-微管蛋白有77.3%的同源性。基因破坏导致细胞死亡,出现浓缩的、未分裂的染色体以及异常的纺锤体结构。抗γ-微管蛋白染色显示,在野生型细胞周期中,γ-微管蛋白始终位于纺锤极体(SPB)上,这表明在没有微管的情况下,γ-微管蛋白与间期SPB相关联。此外,抗γ-微管蛋白免疫荧光染色揭示了细胞质中、细胞赤道处假定的微管组织中心(MTOC),它们仅在有丝分裂末期和胞质分裂期间出现,并且位于两个子细胞新的细胞质微管阵列的中心。在多SPB突变体cut1-cdc11中,抗γ-微管蛋白抗体在细胞核周边显示出许多小点。这些结果证实γ-微管蛋白是微管蛋白超家族的重要成员,表明它可能是MTOC的普遍组成成分,并且与γ-微管蛋白在体内控制微管形成的作用相一致。