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封闭型有丝分裂仍需要核被膜的局部拆解
2020-08-27 15:04

英国MRC分子细胞生物学实验室Buzz Baum、Gautam Dey等研究人员合作发现,封闭型有丝分裂仍需要核被膜的局部拆解。这一研究成果于2020年8月26日在线发表在《自然》上。

研究人员表示,真核生物细胞分裂过程中的关键事件是将核基因组划分为两个核区室。在有丝分裂结束时,真核细胞必须将其复制的基因组的两个副本分隔到两个新的核区室中。它们可以通过先拆解核被膜然后再组装,即“开放型有丝分裂”,或者重新包裹完整的核,然后再一分为二,即“封闭型有丝分裂” 。
 
尽管存在一系列中间状态,这些不同的核分裂模式具有关键特征,但封闭型有丝分裂仍面临独特的拓扑难题。各种真核生物中的有丝分裂研究已有一个多世纪,目前尚不清楚封闭型有丝分裂的生物如何在不损害核完整性的情况下实现双核被膜的分裂。
 
通过使用裂殖酵母(Schizosaccharomyces pombe,封闭型有丝分裂的经典模型)、遗传学、活细胞成像和电子断层扫描,研究人员发现,核分裂是通过连接分离子核的窄桥内核孔局部拆卸而实现的。
 
研究人员确定了蛋白质Les1,它位于内部核膜,并限制了局部核膜对桥中间区的破坏,从而防止了子核的泄漏。因此,在封闭型有丝分裂中,局部核被膜的拆解机制与开放型有丝分裂中的核包膜的拆卸紧密相关,这揭示了各种真核生物中核重塑机制的高保守性。
 
附:英文原文

Title: Closed mitosis requires local disassembly of the nuclear envelope

Author: Gautam Dey, Sin Culley, Scott Curran, Uwe Schmidt, Ricardo Henriques, Wanda Kukulski, Buzz Baum

Issue&Volume: 2020-08-26

Abstract: At the end of mitosis, eukaryotic cells must segregate the two copies of their replicated genome into two new nuclear compartments1. They do this either by first dismantling and later reassembling the nuclear envelope in an ‘open mitosis’ or by reshaping an intact nucleus and then dividing it into two in a ‘closed mitosis’2,3. Mitosis has been studied in a wide variety of eukaryotes for more than a century4, but how the double membrane of the nuclear envelope is split into two at the end of a closed mitosis without compromising the impermeability of the nuclear compartment remains unknown5. Here, using the fission yeast Schizosaccharomyces pombe (a classical model for closed mitosis5), genetics, live-cell imaging and electron tomography, we show that nuclear fission is achieved via local disassembly of nuclear pores within the narrow bridge that links segregating daughter nuclei. In doing so, we identify the protein Les1, which is localized to the inner nuclear envelope and restricts the process of local nuclear envelope breakdown to the bridge midzone to prevent the leakage of material from daughter nuclei. The mechanism of local nuclear envelope breakdown in a closed mitosis therefore closely mirrors nuclear envelope breakdown in open mitosis3, revealing an unexpectedly high conservation of nuclear remodelling mechanisms across diverse eukaryotes.

DOI: 10.1038/s41586-020-2648-3

Source: https://www.nature.com/articles/s41586-020-2648-3

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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