Division of cell nuclei, mitochondria, plastids, and microbodies mediated by mitotic spindle poles in the primitive red alga Cyanidioschyzon merolae
Division of cell nuclei, mitochondria, plastids, and microbodies mediated by mitotic spindle poles in the primitive red alga Cyanidioschyzon merolae
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DOI：
10.1007/s00709-010-0107-y
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发表时间：
2010-05-01
期刊：
影响因子：
2.9
通讯作者：
Kuroiwa, Tsuneyoshi
中科院分区：
文献类型：
--
作者：
Imoto, Yuuta;Fujiwara, Takayuki;Kuroiwa, Tsuneyoshi
为了了解细胞周期，我们不仅要了解有丝分裂，还要了解细胞器的分裂周期。植物和动物细胞含有许多随机分裂的细胞器，因此，很难阐明这些细胞器的分裂周期。我们使用了原始的红色Cyanidioschyzon merolae，因为它包含一个单一的细胞器和质体每个细胞，细胞器分裂可以高度同步的光/暗周期。我们证明了线粒体和质体通过独立的分裂周期（细胞器G1，S，G2和M期）倍增，细胞器分裂发生在细胞核分裂之前。此外，发现细胞器分裂依赖于微管以及细胞核分裂。我们观察到微管动力学的五个阶段：（1）在G1期微管消失，（2）在S期α-微管蛋白分散在细胞质中而不形成微管，（3）在G2期α-微管蛋白组装成纺锤体极，（4）在前期极微管沿着纺锤体排列，（5）在细胞质中形成微管，（6）在细胞质中形成微管。（5）细胞核中的有丝分裂纺锤体在M期形成。显微荧光分析表明，α-微管蛋白的定位强度峰依次为纺锤体极、线粒体、纺锤体极和中央纺锤体区，但总荧光强度在整个有丝分裂期变化不明显，表明细胞核和线粒体的分裂和分离是由纺锤体极体介导的。抑制微管组织诱导细胞核分裂，线粒体分离，和一个单一的膜结合的微体的分裂，这表明类似于细胞核分裂，线粒体分离和微体分裂依赖于微管。
To understand the cell cycle, we must understand not only mitotic division but also organelle division cycles. Plant and animal cells contain many organelles which divide randomly; therefore, it has been difficult to elucidate these organelle division cycles. We used the primitive red alga Cyanidioschyzon merolae, as it contains a single mitochondrion and plastid per cell, and organelle division can be highly synchronized by a light/dark cycle. We demonstrated that mitochondria and plastids multiplied by independent division cycles (organelle G1, S, G2 and M phases) and organelle division occurred before cell-nuclear division. Additionally, organelle division was found to be dependent on microtubules as well as cell-nuclear division. We have observed five stages of microtubule dynamics: (1) the microtubule disappears during the G1 phase; (2) alpha-tubulin is dispersed within the cytoplasm without forming microtubules during the S phase; (3) alpha-tubulin is assembled into spindle poles during the G2 phase; (4) polar microtubules are organized along the mitochondrion during prophase; and (5) mitotic spindles in cell nuclei are organized during the M phase. Microfluorometry demonstrated that the intensity peak of localization of alpha-tubulin changed in the order to spindle poles, mitochondria, spindle poles, and central spindle area, but total fluorescent intensity did not change remarkably throughout mitotic phases suggesting that division and separation of the cell nucleus and mitochondrion is mediated by spindle pole bodies. Inhibition of microtubule organization induced cell-nuclear division, mitochondria separation, and division of a single membrane-bound microbody, suggesting that similar to cell-nuclear division, mitochondrion separation and microbody division are dependent on microtubules.