Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
J Phys Chem Lett. 2021 Jan 14;12(1):294-301. doi: 10.1021/acs.jpclett.0c03052. Epub 2020 Dec 21.
Understanding the mobility of nano-objects in the eukaryotic cell nucleus, at multiple length-scales, is essential for dissecting nuclear structure-function relationships both in space and in time. Here, we demonstrate, using single-molecule fluorescent correlation spectroscopies, that motion of inert probes (proteins, polymers, or nanoparticles) with diameters ranging from 2.6 to 150 nm is mostly unobstructed in a nucleus. Supported by the analysis of electron tomography images, these results advocate the ∼150 nm-wide interchromosomal channels filled with the aqueous diluted protein solution. The nucleus is percolated by these channels to allow various cargos to migrate freely at the nanoscale. We determined the volume of interchromosomal channels in the HeLa cell nucleus to 237 ± 61 fL, which constitutes 34% of the cell nucleus volume. The volume fraction of mobile proteins in channels equals 16% ± 4%, and the concentration is 1 mM.
了解真核细胞核内纳米物体的流动性，在多个长度尺度上，对于剖析核结构-功能关系，无论是在空间上还是在时间上，都是至关重要的。在这里，我们使用单分子荧光相关光谱学证明，直径为 2.6 至 150nm 的惰性探针（蛋白质、聚合物或纳米颗粒）的运动在核内大多是畅通无阻的。电子断层扫描图像的分析结果支持了这一观点，即这些通道充满了含有稀释蛋白质溶液的水相，其宽度约为 150nm。这些通道使细胞核得以渗透，从而允许各种货物在纳米尺度上自由迁移。我们测定了 HeLa 细胞核内染色体间通道的体积为 237±61fL，占细胞核体积的 34%。通道内可移动蛋白质的体积分数等于 16%±4%，浓度为 1mM。
