Poulet Axel, Duc Céline, Voisin Maxime, Desset Sophie, Tutois Sylvie, Vanrobays Emmanuel, Benoit Matthias, Evans David E, Probst Aline V, Tatout Christophe
Université Clermont Auvergne, CNRS, Inserm, GReD, F-63000 Clermont-Ferrand, France.
Sainsbury Laboratory Cambridge, University of Cambridge, Cambridge CB2 1LR, UK.
J Cell Sci. 2017 Feb 1;130(3):590-601. doi: 10.1242/jcs.194712. Epub 2017 Jan 3.
The linker of nucleoskeleton and cytoskeleton (LINC) complex is an evolutionarily well-conserved protein bridge connecting the cytoplasmic and nuclear compartments across the nuclear membrane. While recent data support its function in nuclear morphology and meiosis, its involvement in chromatin organisation has not been studied in plants. Here, 3D imaging methods have been used to investigate nuclear morphology and chromatin organisation in interphase nuclei of the model plant Arabidopsis thaliana in which heterochromatin clusters in conspicuous chromatin domains called chromocentres. Chromocentres form a repressive chromatin environment contributing to transcriptional silencing of repeated sequences, a general mechanism needed for genome stability. Quantitative measurements of the 3D position of chromocentres indicate their close proximity to the nuclear periphery but that their position varies with nuclear volume and can be altered in specific mutants affecting the LINC complex. Finally, we propose that the plant LINC complex contributes to proper heterochromatin organisation and positioning at the nuclear periphery, since its alteration is associated with the release of transcriptional silencing as well as decompaction of heterochromatic sequences.
核骨架与细胞骨架连接复合体（LINC复合体）是一种在进化上高度保守的蛋白质桥，它跨越核膜连接细胞质和细胞核区室。虽然最近的数据支持其在核形态和减数分裂中的功能，但其在植物染色质组织中的作用尚未得到研究。在这里，三维成像方法被用于研究模式植物拟南芥间期细胞核的核形态和染色质组织，在拟南芥中，异染色质聚集在称为染色中心的明显染色质结构域中。染色中心形成一个抑制性染色质环境，有助于重复序列的转录沉默，这是基因组稳定性所需的一种普遍机制。对染色中心三维位置的定量测量表明，它们靠近核周，但它们的位置随核体积而变化，并且在影响LINC复合体的特定突变体中可能会改变。最后，我们提出植物LINC复合体有助于异染色质在核周的正确组织和定位，因为其改变与转录沉默的释放以及异染色质序列的解压缩有关。
