Circadian rhythmicity of gene expression is a conserved feature of cell physiology. This involves fine-tuning between transcriptional and post-transcriptional mechanisms and strongly depends on the metabolic state of the cell. Together these processes guarantee an adaptive plasticity of tissue-specific genetic programs. However, it is unclear how the epigenome and RNA Pol II rhythmicity are integrated. Here we show that the PcG protein EZH1 has a gateway bridging function in postmitotic skeletal muscle cells. On the one hand, the circadian clock master regulator BMAL1 directly controls oscillatory behavior and periodic assembly of core components of the PRC2-EZH1 complex. On the other hand, EZH1 is essential for circadian gene expression at alternate Zeitgeber times, through stabilization of RNA Polymerase II preinitiation complexes, thereby controlling nascent transcription. Collectively, our data show that PRC2-EZH1 regulates circadian transcription both negatively and positively by modulating chromatin states and basal transcription complex stability.

中文翻译：

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PRC2-EZH1 通过协调染色质状态和 RNA 聚合酶 II 复合物稳定性促进昼夜节律基因表达。


基因表达的昼夜节律是细胞生理学的一个保守特征。这涉及转录和转录后机制之间的微调，并且在很大程度上取决于细胞的代谢状态。这些过程共同保证了组织特异性遗传程序的适应性可塑性。然而，目前尚不清楚表观基因组和 RNA Pol II 节律是如何整合的。在这里，我们表明 PcG 蛋白 EZH1 在有丝分裂后骨骼肌细胞中具有门户桥接功能。一方面，昼夜节律时钟主调节器 BMAL1 直接控制 PRC2-EZH1 复合物核心组件的振荡行为和周期性组装。另一方面，EZH1 通过稳定 RNA 聚合酶 II 前起始复合物，从而控制新生转录，对交替 Zeitgeber 时间的昼夜节律基因表达至关重要。总的来说，我们的数据表明，PRC2-EZH1 通过调节染色质状态和基础转录复合物稳定性来负向和正向调节昼夜节律转录。