Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.
Plant Cell. 2023 Sep 1;35(9):3345-3362. doi: 10.1093/plcell/koad169.
Plants cope with various recurring stress conditions that often induce DNA damage, ultimately affecting plant genome integrity, growth, and productivity. The CROWDED NUCLEI (CRWN) family comprises lamin-like proteins with multiple functions, such as regulating gene expression, genome organization, and DNA damage repair in Arabidopsis (Arabidopsis thaliana). However, the mechanisms and consequences of CRWNs in DNA damage repair are largely unknown. Here, we reveal that CRWNs maintain genome stability by forming repairing nuclear bodies at DNA double-strand breaks. We demonstrate that CRWN1 and CRWN2 physically associate with the DNA damage repair proteins RAD51D and SUPPRESSOR OF NPR1-1 Inducible 1 (SNI1) and act in the same genetic pathway to mediate this process. Moreover, CRWN1 and CRWN2 partially localize at γ-H2AX foci upon DNA damage. Notably, CRWN1 and CRWN2 undergo liquid-liquid phase separation to form highly dynamic droplet-like structures with RAD51D and SNI1 to promote the DNA damage response (DDR). Collectively, our data shed light on the function of plant lamin-like proteins in the DDR and maintenance of genome stability.
植物应对各种反复出现的胁迫条件，这些条件常常会诱导 DNA 损伤，最终影响植物基因组的完整性、生长和生产力。CROWDED NUCLEI（CRWN）家族由具有多种功能的核纤层样蛋白组成，如在拟南芥（Arabidopsis thaliana）中调节基因表达、基因组组织和 DNA 损伤修复。然而，CRWNs 在 DNA 损伤修复中的机制和后果在很大程度上是未知的。在这里，我们揭示了 CRWNs 通过在 DNA 双链断裂处形成修复核体来维持基因组稳定性。我们证明 CRWN1 和 CRWN2 与 DNA 损伤修复蛋白 RAD51D 和 NPR1-1 诱导的抑制物 1（SNI1）物理结合，并在相同的遗传途径中发挥作用，介导这一过程。此外，CRWN1 和 CRWN2 在 DNA 损伤后部分定位于 γ-H2AX 焦点。值得注意的是，CRWN1 和 CRWN2 发生液-液相分离，与 RAD51D 和 SNI1 形成高度动态的液滴样结构，从而促进 DNA 损伤反应（DDR）。总之，我们的数据揭示了植物核纤层样蛋白在 DDR 和基因组稳定性维持中的功能。
