Sazer Shelley, Lynch Michael, Needleman Daniel
Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Curr Biol. 2014 Nov 17;24(22):R1099-103. doi: 10.1016/j.cub.2014.10.011.
The origin of the nucleus at the prokaryote-to-eukaryote transition represents one of the most important events in the evolution of cellular organization. The nuclear envelope encircles the chromosomes in interphase and is a selectively permeable barrier between the nucleoplasm and cytoplasm and an organizational scaffold for the nucleus. It remains intact in the 'closed' mitosis of some yeasts, but loses its integrity in the 'open' mitosis of mammals. Instances of both types of mitosis within two evolutionary clades indicate multiple evolutionary transitions between open and closed mitosis, although the underlying genetic changes that influenced these transitions remain unknown. A survey of the diversity of mitotic nuclei that fall between these extremes is the starting point from which to determine the physiologically relevant characteristics distinguishing open from closed mitosis and to understand how they evolved and why they are retained in present-day organisms. The field is now poised to begin addressing these issues by defining and documenting patterns of mitotic nuclear variation within and among species and mapping them onto a phylogenic tree. Deciphering the evolutionary history of open and closed mitosis will complement cell biological and genetic approaches aimed at deciphering the fundamental organizational principles of the nucleus.
原核生物向真核生物转变过程中细胞核的起源是细胞组织进化中最重要的事件之一。核膜在间期围绕染色体，是核质与细胞质之间的选择性渗透屏障，也是细胞核的组织支架。它在一些酵母的“封闭”有丝分裂中保持完整，但在哺乳动物的“开放”有丝分裂中失去完整性。两个进化分支中都存在这两种有丝分裂类型的实例，这表明开放和封闭有丝分裂之间存在多次进化转变，尽管影响这些转变的潜在基因变化仍然未知。对介于这两种极端情况之间的有丝分裂细胞核多样性进行调查，是确定区分开放和封闭有丝分裂的生理相关特征、理解它们如何进化以及为何在当今生物体中保留的起点。该领域现在正准备通过定义和记录物种内部和物种之间有丝分裂核变异的模式，并将它们映射到系统发育树上，来开始解决这些问题。解读开放和封闭有丝分裂的进化历史将补充旨在解读细胞核基本组织原则的细胞生物学和遗传学方法。
