Tight regulation of gene transcription and mRNA splicing is essential for plant growth and development. Here we demonstrate that a plant-specific protein, EMBRYO DEFECTIVE 1579 (EMB1579), controls multiple growth and developmental processes in Arabidopsis. We demonstrate that EMB1579 forms liquid-like condensates both in vitro and in vivo, and the formation of normal-sized EMB1579 condensates is crucial for its cellular functions. We found that some chromosomal and RNA-related proteins interact with EMB1579 compartments, and loss of function of EMB1579 affects global gene transcription and mRNA splicing. Using floral transition as a physiological process, we demonstrate that EMB1579 is involved in FLOWERING LOCUS C (FLC)-mediated repression of flowering. Interestingly, we found that EMB1579 physically interacts with a homologue of Drosophila nucleosome remodeling factor 55-kDa (p55) called MULTIPLE SUPPRESSOR OF IRA 4 (MSI4), which has been implicated in repressing the expression of FLC by forming a complex with DNA Damage Binding Protein 1 (DDB1) and Cullin 4 (CUL4). This complex, named CUL4-DDB1^MSI4, physically associates with a CURLY LEAF (CLF)-containing Polycomb Repressive Complex 2 (CLF-PRC2). We further demonstrate that EMB1579 interacts with CUL4 and DDB1, and EMB1579 condensates can recruit and condense MSI4 and DDB1. Furthermore, emb1579 phenocopies msi4 in terms of the level of H3K27 trimethylation on FLC. This allows us to propose that EMB1579 condensates recruit and condense CUL4-DDB1^MSI4 complex, which facilitates the interaction of CUL4-DDB1^MSI4 with CLF-PRC2 and promotes the role of CLF-PRC2 in establishing and/or maintaining the level of H3K27 trimethylation on FLC. Thus, we report a new mechanism for regulating plant gene transcription, mRNA splicing, and growth and development.

基因转录和 mRNA 剪接的严格调控对植物生长发育至关重要。在这里，我们证明植物特异性蛋白质 EMBRYO DEFECTIVE 1579 (EMB1579) 控制拟南芥中的多个生长和发育过程。我们证明 EMB1579 在体外和体内都形成液体状凝聚物，正常大小的 EMB1579 凝聚物的形成对其细胞功能至关重要。我们发现一些染色体和 RNA 相关蛋白与 EMB1579 区室相互作用， EMB1579功能的丧失会影响全局基因转录和 mRNA 剪接。使用花期转变作为生理过程，我们证明 EMB1579 参与FLOWERING LOCUS C ( FLC)-介导的开花抑制。有趣的是，我们发现 EMB1579 与果蝇核小体重塑因子 55-kDa (p55)的同系物发生物理相互作用，称为 IRA 多重抑制因子 4 (MSI4)，后者通过与 DNA 损伤结合形成复合物来抑制FLC的表达蛋白质 1 (DDB1) 和 Cullin 4 (CUL4)。这个名为 CUL4-DDB1 ^{MSI4 的}复合体与含有 CURLY LEAF (CLF) 的 Polycomb Repressive Complex 2 (CLF-PRC2) 在物理上相关联。我们进一步证明 EMB1579 与 CUL4 和 DDB1 相互作用，EMB1579 凝聚体可以募集和凝聚 MSI4 和 DDB1。此外，emb1579在 H3K27 三甲基化水平方面表型复制msi4飞利浦。这使我们能够提出 EMB1579 凝聚物募集和凝聚 CUL4-DDB1 ^{MSI4复合物，这促进了 CUL4-DDB1 MSI4}与 CLF-PRC2的相互作用，并促进了 CLF-PRC2 在建立和/或维持 H3K27 三甲基化水平方面的作用飞利浦。因此，我们报告了一种调节植物基因转录、mRNA 剪接和生长发育的新机制。