ISOLATION AND CHARACTERIZATION OF SCHIZOSACCHAROMYCES-POMBE CUT MUTANTS THAT BLOCK NUCLEAR DIVISION BUT NOT CYTOKINESIS
ISOLATION AND CHARACTERIZATION OF SCHIZOSACCHAROMYCES-POMBE CUT MUTANTS THAT BLOCK NUCLEAR DIVISION BUT NOT CYTOKINESIS
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DOI：
10.1002/j.1460-2075.1986.tb04594.x
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发表时间：
1986-11-01
期刊：
影响因子：
11.4
通讯作者：
YANAGIDA, M
中科院分区：
文献类型：
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作者：
HIRANO, T;FUNAHASHI, S;YANAGIDA, M
通过对裂殖酵母裂殖酵母的587个温度敏感突变体的细胞学表型的研究，我们获得了18个突变体，这些突变体在没有核分裂的情况下引起细胞分裂。通过遗传分析，这些新的核分裂阻滞突变体可分为9个互补组（命名为cut 1-cut 9）。切割突变体的细胞学表型与DNA拓扑异构酶II突变体（top2）相似但不相同。通过转化克隆了cut 1+基因，并显示其与cut 2和cut 1互补，表明这两个基因之间存在功能关系。切割基因是核分裂所必需的，但它们的突变体表型不同于大多数先前鉴定的阻断核分裂以及随后的胞质分裂的突变体。荧光显微镜检查表明，切割突变细胞中形成的有丝分裂染色体是异常的，不能正确分离。我们认为，削减突变，如top2，阻止有丝分裂染色体的形成和伴随的核分裂，但胞质分裂的进展独立的核分裂缺陷，表现出不协调的有丝分裂途径。还描述了一种新的突变体nuc 1，其显示出与DNA拓扑异构酶I和II的双突变体相似的细胞学表型，但含有正常水平的DNA拓扑异构酶活性。
By examining cytological phenotypes of 587 temperature-sensitive mutants of the fission yeast Schizosaccharomyces pombe, we obtained 18 mutants which cause cell division in the absence of nuclear division. By genetic analyses, these novel nuclear division arrest mutants can be classified into nine complementation groups (designated cut1-cut9). The cytological phenotype of cut mutants is similar but not identical to that of DNA topoisomerase II mutants (top2). The cut1+ gene was cloned by transformation and shown to complement cut2 as well as cut1, indicating a functional relationship between the two genes. The cut genes are required for nuclear division, but their mutant phenotypes differ from most of the previously identified mutants which block nuclear division and also the subsequent cytokinesis. Fluorescence microscopy indicates that the mitotic chromosomes formed in cut mutant cells are abnormal and fail to separate properly. We suggest that cut mutations, like top2, block mitotic chromosome formation and concomitantly nuclear division, but that cytokinesis proceeds independently of the defects in nuclear division, demonstrating uncoordinated mitotic pathways. A novel mutant nuc1 is also described which shows a cytological phenotype similar to the double mutant of DNA topoisomerases I and II but contains normal levels of both DNA topoisomerase activities.