Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan.
Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan.
Life Sci Alliance. 2021 Feb 3;4(4). doi: 10.26508/lsa.202001005. Print 2021 Apr.
Liquid droplets formed inside the cell by liquid-liquid phase separation maintain membrane-less condensates/bodies (or compartments). These droplets are important for concentrating certain molecules and facilitating spatiotemporal regulation of cellular functions. 1,6-hexanediol (1,6-HD), an aliphatic alcohol, inhibits weak hydrophobic protein-protein/protein-RNA interactions required for the droplet formation (droplet melting activity) and is used here to elucidate the formation process of cytoplasmic/nuclear condensates/bodies. However, the effect of 1,6-HD on chromatin in living cells remains unclear. We found that 1,6-HD drastically suppresses chromatin motion and hyper-condenses chromatin in human cells by using live-cell single-nucleosome imaging, which detects changes in the state of chromatin. These effects were enhanced in a dose-dependent manner. Chromatin was "frozen" by 5%, or higher, concentrations of 1,6-HD. 1,6-HD greatly facilitated cation-dependent chromatin condensation in vitro. This 1,6-HD action is distinct from its melting activity of liquid droplets. Alcohols, such as 1,6-HD, appear to remove water molecules around chromatin and locally condense chromatin. Therefore, liquid droplet results obtained using 1,6-HD should be carefully interpreted or reconsidered when these droplets are associated with chromatin.
液-液相分离在细胞内形成的液滴维持无膜凝聚物/体（或隔室）。这些液滴对于浓缩某些分子和促进细胞功能的时空调节很重要。1,6-己二醇（1,6-HD），一种脂肪族醇，抑制液滴形成（液滴融化活性）所需的弱疏水性蛋白-蛋白/蛋白-RNA 相互作用，并在此用于阐明细胞质/核凝聚物/体的形成过程。然而，1,6-HD 对活细胞中染色质的影响尚不清楚。我们发现，通过使用活细胞单核小体成像来检测染色质状态的变化，1,6-HD 可显着抑制人细胞中的染色质运动并使染色质高度浓缩。这些作用呈剂量依赖性增强。染色质在 5%或更高浓度的 1,6-HD 下“冻结”。1,6-HD 极大地促进了阳离子依赖性染色质的体外浓缩。这种 1,6-HD 作用与液滴的融化活性不同。醇类，如 1,6-HD，似乎可以去除围绕染色质的水分子并局部浓缩染色质。因此，当这些液滴与染色质相关联时，应仔细解释或重新考虑使用 1,6-HD 获得的液滴结果。
