3D-Visualization of the Precise Location of Symbiotic Organelle Crosstalk Throughout Mitosis in the Primitive Unicellular Eukaryotic Cell, C. Merolae
3D-Visualization of the Precise Location of Symbiotic Organelle Crosstalk Throughout Mitosis in the Primitive Unicellular Eukaryotic Cell, C. Merolae
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原始单细胞真核细胞 C. Merolae 有丝分裂过程中共生细胞器串扰精确位置的 3D 可视化
DOI：
10.1016/j.bpj.2016.11.3103
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发表时间：
2017
影响因子：
3.4
通讯作者：
Atsuko H. Iwane
中科院分区：
文献类型：
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作者：
Takako Ichinose;Keisuke Ohta;Atsuko H. Iwane
近年来，共生研究进展迅速，宏基因组学分析采用了新一代DNA测序技术、基因生物学技术和代谢组学分析技术。在最原始的已知共生形式中，被称为“初级内共生”，亚细胞器是被异养真核生物吸收的细菌，特别是分别来自祖先蓝细菌和α变形菌的质体和线粒体。我们正在研究不同的有机体是如何整合并开始作为一个整体生活的。我们选择了C。merolae，一种原始的单细胞红藻，作为一个很好的共生模式生物，重点是有丝分裂过程中使用双光束EM和共聚焦LM。C. merolae是一种小的（2-5微米）真核细胞，并且非常简单，仅含有少量的双膜和单膜细胞器，并且缺乏细胞壁，并且从远古时代就存活下来。在细胞分裂过程中，母细胞分裂并将每个细胞器平均分配到子细胞中。我们确定了每个有丝分裂阶段使用特定的荧光标记，以及从光学延时观察获得的单个细胞的动态形状变化。通过使用纤维束扫描电镜和三维重建技术，我们成功地观察到更详细的单个主要细胞器的形状变化，这揭示了特定的强相互作用，并表明细胞器串扰特定于有丝分裂期是必不可少的共生关系。此外，利用超高压电镜断层扫描的质体，我们观察到的捕光天线复合体上的类囊体膜详细。发现外分裂环和内分裂环分别由存在于现代真核生物和细菌中的蛋白质构成。因此，C的一个基本元素。揭示了有丝分裂中merolae共生细胞器的串扰。在揭示真核生物和细菌之间的确切共生关系时，我们可以开发出也适用于由更大生物多样性组成的更大生态系统的参数。
In recent years, symbiosis research has been progressing rapidly with metagenomics analysis using Next-generation DNA sequencing, gnotobiotic technology and metabolome analysis technology. In the most primitive known form of symbiosis, referred to as “primary endosymbiosis”, the subcellular organelles were bacteria taken up by a heterotrophic eukaryote, specifically plastids and mitochondria originated from ancestral Cyanobacteria and Alphaproteobacteria respectively. We are studying how the different organisms are integrated and began to live as one. We selected C. merolae, a primitive unicellular red algae, as an excellent symbiosis model organism and focus on the mitosis process using dualbeam EM and confocal LM. C. merolae is a small (2-5 micron) eukaryotic cell and is extremely simple, containing only an few double-membraned and single-membraned organelles and lacking a cell wall, and has survived from ancient times. During cell division, the parent cell divides and distributes each organelle equally into daughter cells. We identified each mitotic phase using specific fluorescent tags as well as by the dynamic shape change of individual cells obtained from optical time-lapse observation. By using FIB-SEM and 3D-reconstruction techniques we successfully observed the shape changes of the individual main organelles in greater detail which revealed specific strong interactions and suggests organelle crosstalk specific to mitotic phase is essential to the symbiotic relationship. Furthermore, using UHVEM tomography of the plastid, we observed the light harvesting antennae complex onto the thylakoid membrane in detail. The outer division ring and inner division ring were found to be constructed of proteins which are present in modern eukaryotes and bacteria respectively. Thus a fundamental element of C. merolae symbiotic organelle crosstalk in mitosis is revealed. In revealing the precise symbiotic relationship between eukaryote and bacteria we can develop the parameters which will also apply to larger ecological systems consisting of greater biological diversity.