The Mediator subunit MED23 couples H2B mono‐ubiquitination to transcriptional control and cell fate determination
The Mediator subunit MED23 couples H2B mono‐ubiquitination to transcriptional control and cell fate determination
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DOI：
10.15252/embj.201591279
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发表时间：
2015-12
期刊：
影响因子：
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通讯作者：
Xiao Yao;Zhanyun Tang;Xing Fu;Jing-wen Yin;Yan Liang;Chonghui Li;Huayun Li;Qing Tian;
中科院分区：
文献类型：
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作者：
Xiao Yao;Zhanyun Tang;Xing Fu;Jing-wen Yin;Yan Liang;Chonghui Li;Huayun Li;Qing Tian;
调解复杂协调多个转录因子与Pol II仪器精确转录控制。然而，它与周围染色质的相互作用仍然知之甚少。在这里，我们分析了WT和MED23−/−(KO)细胞之间组蛋白修饰的差异，并鉴定了赖氨酸120位点的H2B单泛素化（H2Bub）是MED23依赖性组蛋白修饰。通过串联亲和纯化和质谱分析，我们发现MED23与RNF20/40复合物（H2Bub酶）结合，并表明这种结合对于RNF20/40募集到染色质上至关重要。在无细胞系统中，Mediator通过与RNF20/40和PAF复合物的合作，直接并大量增加重组染色质上的H2Bub。整合全基因组分析表明，MED23缺失特异性地降低了MED23控制基因子集上的H2Bub。重要的是，MED23偶联的H2Bub水平在肌发生和肺癌发生过程中受到相反的调节。总之，这些结果建立了中介复合物和关键染色质修饰之间的机制联系，以协调转录与细胞生长和分化。
The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23−/− (KO) cells and identify H2B mono‐ubiquitination at lysine 120 (H2Bub) as a MED23‐dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell‐free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome‐wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23‐controlled genes. Importantly, MED23‐coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation.