Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany.
Buck Institute for Research on Aging, Novato, United States.
Elife. 2020 Feb 5;9:e48160. doi: 10.7554/eLife.48160.
Intestinal stem cells (ISCs) maintain regenerative capacity of the intestinal epithelium. Their function and activity are regulated by transcriptional changes, yet how such changes are coordinated at the genomic level remains unclear. The Cohesin complex regulates transcription globally by generating topologically-associated DNA domains (TADs) that link promotor regions with distant enhancers. We show here that the Cohesin complex prevents premature differentiation of ISCs into enterocytes (ECs). Depletion of the Cohesin subunit Rad21 and the loading factor Nipped-B triggers an ISC to EC differentiation program that is independent of Notch signaling, but can be rescued by over-expression of the ISC-specific escargot (esg) transcription factor. Using damID and transcriptomic analysis, we find that Cohesin regulates Esg binding to promoters of differentiation genes, including a group of Notch target genes involved in ISC differentiation. We propose that Cohesin ensures efficient Esg-dependent gene repression to maintain stemness and intestinal homeostasis.
肠干细胞(ISCs)维持肠道上皮的再生能力。它们的功能和活性受转录变化的调节,但这种变化如何在基因组水平上协调仍然不清楚。黏合蛋白复合物通过生成拓扑相关 DNA 结构域(TADs)来全局调控转录,将启动子区域与远距离增强子连接起来。我们在这里表明,黏合蛋白复合物可防止 ISC 过早分化为肠上皮细胞(ECs)。黏合蛋白亚基 Rad21 和加载因子 Nipped-B 的耗竭会触发 ISC 向 EC 分化程序,该程序独立于 Notch 信号,但可通过过表达 ISC 特异性 escargot(esg)转录因子得到挽救。通过 damID 和转录组分析,我们发现黏合蛋白调节 Esg 与分化基因启动子的结合,包括一组参与 ISC 分化的 Notch 靶基因。我们提出,黏合蛋白确保有效的 Esg 依赖性基因抑制以维持干细胞特性和肠道内稳态。