The kinetochore and the origin of eukaryotic chromosome segregation.
The kinetochore and the origin of eukaryotic chromosome segregation.
复制标题
动粒和真核染色体分离的起源。
DOI：
10.1073/pnas.1908067116
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发表时间：
2019
影响因子：
11.1
通讯作者：
Field MC
中科院分区：
文献类型：
--
作者：
Field MC
所有生物在细胞分裂过程中都必须忠实地分离它们的DNA，以确保基因组的完全遗传。在真核生物中，细胞和核分裂的机制是高度不同的，虽然这些通常涉及使用基于有丝分裂微管的纺锤体和物理上连接染色质和纺锤体的动粒(KT)，但除此之外，完成有丝分裂的安排和方式可以采用大量不同的途径之一(1，2)。这些途径中的每一条都需要多种细胞功能的参与，包括核骨架、着丝粒(染色质标记的KT组装位点)、核膜和核孔复合体(NPC)，以实现将完整的基因组分割为两个子细胞的最终目标。由于真核生物基因组包含在多个DNA元件上，并且经常是二倍体，这使得这项任务变得更加具有挑战性。在PNAS中，Tromer等人(3)使用高度敏感的序列和结构搜索方法重温了关键成分KT的起源，以提供可能的进化史。有丝分裂机制的多样性可以追溯到我们的原核生物祖先，其中染色体在来自不同细菌系的细胞内显示出不同的物理排列，这就需要一个适应组织(4，5)。用于分离大量细菌谱系中的染色体的ParABS系统，包括新月桂枝杆菌，远不是通用的(6，7)，例如，不被大肠杆菌使用，其中mukBEF SMC复合体工作(8，9)。人们对这些原核和真核机制是如何进化的，包括它们的起源和本质上相同问题的不同解决方案之间的关系有相当大的兴趣。对于真核生物来说，最后一个真核共同祖先(LECA)中系统的配置是重建真核生物进化史的一个重要方面(图1A)。最重要的是，没有证据表明已知的细菌染色体之间存在共同的下降
All organisms must faithfully segregate their DNA during cell division to safeguard complete inheritance of the genome. In eukaryotes, mechanisms of cell and nuclear division are highly variable, and while these usually involve the use of a mitotic microtubule-based spindle and a kinetochore (KT) that physically links the chromatin and spindle, beyond this, the arrangement and manner in which mitosis is completed can adopt one of a vast number of disparate pathways (1, 2). Each of these pathways requires the participation of multiple cellular functions, including the nucleoskeleton, centromeres (chromatin-marked KT assembly sites), the nuclear envelope, and the nuclear pore complex (NPC), to achieve the ultimate goal of partitioning a complete genome to both daughter cells. Because the eukaryotic genome is contained on multiple DNA elements and is frequently diploid makes this task even more challenging. In PNAS, Tromer et al.(3) revisit the origin of a key component, the KT, using highly sensitive sequence and architectural search methods to provide a possible evolutionary history.Variability in mitotic mechanisms stretches back to our prokaryotic ancestors, where chromosomes exhibit distinct physical arrangements within cells from different bacterial linages and which then necessitates an accommodating organization (4, 5). The parABS system, which is used for segregation of chromosomes in a large number of bacterial lineages, including Caulobacter crescentus, is far from universal, however (6, 7), and is not used by Escherichia coli, for example, where the mukBEF SMC complex operates (8, 9). There is considerable interest into how these prokaryotic and eukaryotic mechanisms evolved, including their origins and the relationships between these disparate solutions for essentially the same problem. For eukaryotes, the configuration of the system in the last eukaryotic common ancestor (LECA) is an important facet of reconstructions of eukaryote evolutionary history (Fig. 1A). Most importantly, there is no evidence for common descent between known bacterial chromosome