Tumour Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain; Cellular Plasticity and Disease Group, Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain.
Tumour Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain.
Cell Rep. 2018 Jan 9;22(2):396-410. doi: 10.1016/j.celrep.2017.12.062.
The RNA polymerase II-associated protein 1 (RPAP1) is conserved across metazoa and required for stem cell differentiation in plants; however, very little is known about its mechanism of action or its role in mammalian cells. Here, we report that RPAP1 is essential for the expression of cell identity genes and for cell viability. Depletion of RPAP1 triggers cell de-differentiation, facilitates reprogramming toward pluripotency, and impairs differentiation. Mechanistically, we show that RPAP1 is essential for the interaction between RNA polymerase II (RNA Pol II) and Mediator, as well as for the recruitment of important regulators, such as the Mediator-specific RNA Pol II factor Gdown1 and the C-terminal domain (CTD) phosphatase RPAP2. In agreement, depletion of RPAP1 diminishes the loading of total and Ser5-phosphorylated RNA Pol II on many genes, with super-enhancer-driven genes among the most significantly downregulated. We conclude that Mediator/RPAP1/RNA Pol II is an ancient module, conserved from plants to mammals, critical for establishing and maintaining cell identity.
RNA 聚合酶 II 相关蛋白 1（RPAP1）在后生动物中保守，并且在植物中对干细胞分化是必需的；然而，关于其作用机制或在哺乳动物细胞中的作用知之甚少。在这里，我们报告 RPAP1 对于细胞身份基因的表达和细胞活力是必需的。RPAP1 的耗竭会触发细胞去分化，促进向多能性的重编程，并损害分化。从机制上讲，我们表明 RPAP1 对于 RNA 聚合酶 II（RNA Pol II）和中介体之间的相互作用以及 Mediator 特异性 RNA Pol II 因子 Gdown1 和 C 末端结构域（CTD）磷酸酶 RPAP2 等重要调节剂的募集是必需的。一致地，RPAP1 的耗竭会减少许多基因上总 RNA Pol II 和 Ser5 磷酸化 RNA Pol II 的加载，其中超级增强子驱动的基因下调最为显著。我们得出结论，中介体/RPAP1/RNA Pol II 是一个古老的模块，从植物到哺乳动物都保守，对于建立和维持细胞身份至关重要。
