BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Peking-Tsinghua Center for Life Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China.
Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, P. R. China.
Angew Chem Int Ed Engl. 2019 Apr 1;58(15):4858-4862. doi: 10.1002/anie.201810373. Epub 2019 Mar 12.
Phase separation of proteins/nucleic acids to form non-membrane organelles is crucial in cellular gene-expression regulation. However, little is known about transcriptional regulator phase separation and the underlying molecular mechanism. Vernalization 1 (VRN1) encodes a crucial transcriptional repressor involved in plant vernalization that contains two B3 DNA-binding domains connected by an intrinsic disorder region (IDR) and nonspecifically binds DNA. We found that the Arabidopsis VRN1 protein undergoes liquid-liquid phase separation (LLPS) with DNA that is driven by multivalent protein-DNA interactions (LLPS), and that both B3 domains are required. The distribution of charged residues in the VRN1 IDR modulates the interaction strength between VRN1 and DNA, and changes in the charge pattern lead to interconversion between different states (precipitates, liquid droplets, and no phase separation). We further showed that VRN1 forms puncta in plant cell nuclei, suggesting that it may stabilize the vernalized state by repressing gene expression through LLPS.
蛋白质/核酸的液-液相分离（LLPS）形成非膜细胞器，这对细胞基因表达调控至关重要。然而，人们对转录调控因子的液-液相分离及其潜在的分子机制知之甚少。春化素 1（VRN1）编码一种关键的转录抑制因子，参与植物春化作用，它包含两个 B3 DNA 结合结构域，由一个固有无序区（IDR）连接，并能非特异性地结合 DNA。我们发现，拟南芥 VRN1 蛋白与 DNA 发生液-液相分离（LLPS），这是由多价蛋白-DNA 相互作用（LLPS）驱动的，并且需要两个 B3 结构域。VRN1 IDR 中的带电残基分布调节了 VRN1 与 DNA 之间的相互作用强度，而电荷模式的变化则导致不同状态（沉淀、液滴和无液-液相分离）之间的转换。我们进一步表明，VRN1 在植物细胞核中形成斑点，表明它可能通过液-液相分离来抑制基因表达，从而稳定春化状态。
