體外和活細胞研究表明濃縮染色質在中尺度上表現為固體
作者：
小柯機器人發布時間：2020/12/16 15:40:42
加拿大艾伯塔大學Michael J. Hendzel和美國科羅拉多州立大學Jeffrey C. Hansen研究小組合作發現，在體外和活細胞中濃縮染色質表現為固體狀。該研究成果在線發表在2020年12月15日的《細胞》。
在本研究中，研究人員揭示了體外和體內濃縮染色質的物理狀態。體外研究表明，在廣泛溶液條件下，核小體序列的自締合會產生超分子聚集物，在這種情況下染色質收縮並呈固體狀。通過測量活細胞中DNA的遷移率，研究人員證明了濃縮染色質在體內同樣也呈現固體態。然而，典型異染色質蛋白則呈現液體態並聚集在固體樣染色質結構周圍。
重要的是，即使在染色質纖維之間產生有限相互作用的條件下，常染色質和異染色質仍具有類似的固體狀態。該研究結果表明，濃縮染色質以固態存在，其可以抵抗外力並產生彈性凝膠，這提供了支持染色質結合蛋白液-液相分離的基礎。
研究人員表示，細胞核DNA與組蛋白結合形成染色質對於真核生物基因組的時間和空間調控至關重要。
附：英文原文
Title: Condensed Chromatin Behaves like a Solid on the Mesoscale In Vitro and in Living Cells
Author: Hilmar Strickfaden, Thomas O. Tolsma, Ajit Sharma, D. Alan Underhill, Jeffrey C. Hansen, Michael J. Hendzel
Issue&Volume: 2020-12-15
Abstract: The association of nuclear DNA with histones to form chromatin is essential for temporaland spatial control of eukaryotic genomes. In this study, we examined the physicalstate of condensed chromatin in vitro and in vivo. Our in vitro studies demonstrate that self-association of nucleosomal arrays under a wide rangeof solution conditions produces supramolecular condensates in which the chromatinis physically constrained and solid-like. By measuring DNA mobility in living cells,we show that condensed chromatin also exhibits solid-like behavior in vivo. Representative heterochromatin proteins, however, display liquid-like behavior andcoalesce around the solid chromatin scaffold. Importantly, euchromatin and heterochromatinshow solid-like behavior even under conditions that produce limited interactions betweenchromatin fibers. Our results reveal that condensed chromatin exists in a solid-likestate whose properties resist external forces and create an elastic gel and providesa scaffold that supports liquid-liquid phase separation of chromatin binding proteins.
DOI: 10.1016/j.cell.2020.11.027
Source: https://www.cell.com/cell/fulltext/S0092-8674(20)31544-0
Cell：《細胞》，創刊於1974年。隸屬於細胞出版社，最新IF：36.216