The polyubiquitin gene is essential for meiosis in fission yeast.
The polyubiquitin gene is essential for meiosis in fission yeast.
复制标题
DOI：
10.1006/excr.1999.4728
复制
发表时间：
2000-01
影响因子：
3.7
通讯作者：
K. Okazaki;H. Okayama;O. Niwa
中科院分区：
文献类型：
--
作者：
K. Okazaki;H. Okayama;O. Niwa
我们分离出一种新的粟酒裂殖酵母孢子形成缺陷突变体。该突变体没有有丝分裂生长缺陷，但在第一次或第二次分裂时减数分裂失败，染色体浓缩，无法分离，纺锤体异常，纺锤体极体（SPB）解体。在第一次分裂期间，着丝粒被拉至纺锤体极附近，但浓缩的二价染色体仍保留在中心。在用绿色荧光蛋白标记的 SPB 蛋白的延时记录过程中也观察到无法进入后期。编码串联融合的八个泛素的多聚泛素基因 ubi4(+) 补充了该突变体。该突变（A 至 G 取代）是在 ubi4(+) 基因的 ATG 起始密码子处发现的。 ubi4(+) 基因的破坏产生了相同的表型。 ubi4(+) mRNA 强烈诱导减数分裂。然而，泛素仅略有增加，这表明多聚泛素基因的作用是提供被未知机制消耗的泛素。 ubi4突变细胞在进入减数分裂前，泛素大幅减少，表明泛素缺乏导致减数分裂流产。这项工作为了解多聚泛素基因的作用以及泛素化在减数分裂 SPB 完整性中的重要性提供了见解。
We isolated a novel sporulation-deficient mutant of Schizosaccharomyces pombe. The mutant did not have a mitotic growth defect but aborted meiosis at the first or the second division with condensed chromosomes that failed to separate, abnormal spindle(s), and disintegrated spindle pole bodies (SPBs). During the first division, the centromeres were pulled to near the spindle poles but condensed divalent chromosomes remained at the center. The failure to proceed to anaphase was also observed during a time-lapse recording of a SPB protein tagged with green fluorescent protein. The polyubiquitin gene ubi4(+), which encoded eight ubiquitins fused in tandem, complemented this mutant. The mutation, an A to G substitution, was identified within the ubi4(+) gene at the ATG initiation codon. Disruption of the ubi4(+) gene produced the same phenotypes. The ubi4(+) mRNA was strongly induced for meiosis. However, ubiquitin increases only slightly, suggesting that the role of the polyubiquitin gene is to supply ubiquitin that is consumed by unidentified mechanisms. Before the ubi4 mutant cells entered meiosis, ubiquitin was greatly decreased indicating that shortage of ubiquitin caused abortion of meiosis. This work provides insights for the role of polyubiquitin gene and importance of ubiquitination in SPB integrity at the meiotic divisions.