期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：26
页码：12596-12598
DOI：10.1073/pnas.1908067116
出版社：The National Academy of Sciences of the United States of America
摘要：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. 1 A ). Most … [↵][1]1Email: mfield{at}mac.com.
