Deletion of the topoisomerase III gene in the hyperthermophilic archaeon Sulfolobus islandicus results in slow growth and defects in cell cycle control
Deletion of the topoisomerase III gene in the hyperthermophilic archaeon Sulfolobus islandicus results in slow growth and defects in cell cycle control
复制标题
超嗜热古细菌岛硫化叶菌中拓扑异构酶 III 基因的缺失导致生长缓慢和细胞周期控制缺陷
DOI：
10.1016/j.jgg.2011.05.001
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发表时间：
2011-06-01
影响因子：
5.9
通讯作者：
Huang, Li
中科院分区：
文献类型：
--
作者：
Li, Xiyang;Guo, Li;Huang, Li
拓扑异构酶III(Topo III)是一种IA型拓扑异构酶，广泛存在于嗜热古生菌中。为了探讨古细菌Topo III在体内的作用，我们构建并鉴定了岛柳Topo III基因缺失突变体。突变株是有活力的，但生长速度比野生型菌株慢，特别是在营养不良的介质中。流式细胞仪分析显示，突变体的生长周期特征发生了变化，包括在指数生长的培养中，含有两个以上基因组等价物或少于一个基因组等价物的细胞比例增加。荧光显微镜显示，培养物中的一部分突变细胞急剧扩大，至少部分扩大的细胞明显能够恢复细胞分裂。突变体还表现出与野生型菌株不同的转录图谱。我们的结果表明，该酶可能在染色体分离和细胞内超螺旋水平的控制中发挥作用。
Topoisomerase III (topo III), a type IA topoisomerase, is widespread in hyperthermophilic archaea. In order to interrogate the in vivo role of archaeal topo III, we constructed and characterized a topo III gene deletion mutant of Sulfolobus islandicus. The mutant was viable but grew more slowly than the wild-type strain, especially in a nutrient-poor medium. Flow cytometry analysis revealed changes of the mutant in growth cycle characteristics including an increase in proportion of cells containing either more than two genome equivalents or less than one genome equivalent in exponentially-growing cultures. As shown by fluorescence microscopy, a fraction of mutant cells in the cultures were drastically enlarged, and at least some of the enlarged cells were apparently capable of resuming cell division. The mutant also shows a different transcriptional profile from that of the wild-type strain. Our results suggest that the enzyme may serve roles in chromosomal segregation and control of the level of supercoiling in the cell.