PDF(Pubmed)
Abstract：
The Mediator complex is an evolutionarily conserved multi-subunit protein complex that plays major roles in transcriptional activation and is essential for cell growth, proliferation, and differentiation. Recent studies revealed that some Mediator subunits formed nuclear condensates that may facilitate enhancer-promoter interactions and gene activation. The assembly, regulation, and functions of these nuclear condensates remain to be further understood.
We found that Med15, a subunit in the tail module of the Mediator complex, formed nuclear condensates through a novel mechanism. Nuclear foci of Med15 were detected by both immunostaining of endogenous proteins and live cell imaging. Like Med1 foci and many other biomolecular condensates, Med15 foci were sensitive to 1, 6-Hexanediol and showed rapid recovery during fluorescence recovery after photobleaching. Interestingly, overexpressing DYRK3, a dual-specificity kinase that controls the phase transition of membraneless organelles, appeared to disrupt Med1 foci and Med15 foci. We identified two regions that are required to form Med15 nuclear condensates: the glutamine-rich intrinsically disordered region (IDR) and a short downstream hydrophobic motif. The optodroplet assay revealed that both the IDR and the C-terminal region of Med15 contributed to intracellular phase separation.
We identified that the Mediator complex subunit Med15 formed nuclear condensates and characterized their features in living cells. Our work suggests that Med15 plays a role in the assembly of transcription coactivator condensates in the nucleus and identifies Med15 regions that contribute to phase separation.
We found that Med15, a subunit in the tail module of the Mediator complex, formed nuclear condensates through a novel mechanism. Nuclear foci of Med15 were detected by both immunostaining of endogenous proteins and live cell imaging. Like Med1 foci and many other biomolecular condensates, Med15 foci were sensitive to 1, 6-Hexanediol and showed rapid recovery during fluorescence recovery after photobleaching. Interestingly, overexpressing DYRK3, a dual-specificity kinase that controls the phase transition of membraneless organelles, appeared to disrupt Med1 foci and Med15 foci. We identified two regions that are required to form Med15 nuclear condensates: the glutamine-rich intrinsically disordered region (IDR) and a short downstream hydrophobic motif. The optodroplet assay revealed that both the IDR and the C-terminal region of Med15 contributed to intracellular phase separation.
We identified that the Mediator complex subunit Med15 formed nuclear condensates and characterized their features in living cells. Our work suggests that Med15 plays a role in the assembly of transcription coactivator condensates in the nucleus and identifies Med15 regions that contribute to phase separation.
摘要：
Mediator复合物是一种进化保守的多亚基蛋白复合物，在转录激活中起着重要作用，对细胞生长至关重要。扩散,和差异化。最近的研究表明，一些介体亚基形成核缩合物，可能促进增强子-启动子相互作用和基因激活。大会,regulation,和这些核缩合物的功能还有待进一步理解。
我们发现Med15是Mediator复合体尾部模块中的一个亚基，通过一种新的机制形成核凝聚物。通过内源性蛋白的免疫染色和活细胞成像检测Med15的核病灶。像Med1焦点和许多其他生物分子缩合物一样，Med15焦点对1，6-己二醇敏感，并且在光漂白后的荧光恢复过程中显示出快速恢复。有趣的是,过表达DYRK3，一种控制无膜细胞器相变的双特异性激酶，似乎破坏Med1病灶和Med15病灶。我们确定了形成Med15核缩合物所需的两个区域：富含谷氨酰胺的固有无序区域（IDR）和较短的下游疏水基序。光液滴测定显示Med15的IDR和C末端区域均有助于细胞内相分离。
我们确定了Mediator复合物亚基Med15形成了核缩合物，并在活细胞中表征了它们的特征。我们的工作表明，Med15在细胞核中转录共激活子缩合物的组装中起作用，并鉴定了有助于相分离的Med15区域。
我们发现Med15是Mediator复合体尾部模块中的一个亚基，通过一种新的机制形成核凝聚物。通过内源性蛋白的免疫染色和活细胞成像检测Med15的核病灶。像Med1焦点和许多其他生物分子缩合物一样，Med15焦点对1，6-己二醇敏感，并且在光漂白后的荧光恢复过程中显示出快速恢复。有趣的是,过表达DYRK3，一种控制无膜细胞器相变的双特异性激酶，似乎破坏Med1病灶和Med15病灶。我们确定了形成Med15核缩合物所需的两个区域：富含谷氨酰胺的固有无序区域（IDR）和较短的下游疏水基序。光液滴测定显示Med15的IDR和C末端区域均有助于细胞内相分离。
我们确定了Mediator复合物亚基Med15形成了核缩合物，并在活细胞中表征了它们的特征。我们的工作表明，Med15在细胞核中转录共激活子缩合物的组装中起作用，并鉴定了有助于相分离的Med15区域。
