DNA TOPOISOMERASE-II MUTANT OF SACCHAROMYCES-CEREVISIAE - TOPOISOMERASE-II IS REQUIRED FOR SEGREGATION OF DAUGHTER MOLECULES AT THE TERMINATION OF DNA-REPLICATION
DNA TOPOISOMERASE-II MUTANT OF SACCHAROMYCES-CEREVISIAE - TOPOISOMERASE-II IS REQUIRED FOR SEGREGATION OF DAUGHTER MOLECULES AT THE TERMINATION OF DNA-REPLICATION
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DOI：
10.1073/pnas.81.9.2616
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发表时间：
1984-01-01
期刊：
影响因子：
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通讯作者：
STERNGLANZ, R
中科院分区：
文献类型：
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作者：
DINARDO, S;VOELKEL, K;STERNGLANZ, R
对酿酒酵母DNA拓扑异构酶II的温度敏感型突变株进行了鉴定。遗传分析表明，温度敏感的生长和酶活性都是由单个隐性核突变引起的。因此，拓扑异构酶II是生存所必需的，突变很可能发生在结构基因上。对同步突变细胞的实验表明，在不允许的温度下，细胞可以经历1轮且只有1轮DNA复制。这些细胞在内侧核分裂时被截住。对这些细胞中的2-微米质粒DNA的分析表明，它是以多个相互缠绕的链状二聚体的形式存在的。DNA拓扑异构酶II可能是DNA复制终止时染色体分离所必需的。
A temperature-sensitive DNA topoisomerase II mutant of the yeast S. cerevisiae was identified. Genetic analysis shows that a single recessive nuclear mutation is responsible for both temperature-sensitive growth and enzymatic activity. Thus, topoisomerase II is essential for viability and the mutation is most probably in the structural gene. Experiments with synchronized mutant cells show that at the nonpermissive temperature cells can undergo 1, and only 1, round of DNA replication. These cells are arrested at medial nuclear division. Analysis of 2-.mu.m plasmid DNA from these cells shows it to be in the form of multiply intertwined catenated dimers. DNA topoisomerase II is probably necessary for the segregation of chromosomes at the termination of DNA replication.