Xue Yong, Pradhan Suman K, Sun Fei, Chronis Constantinos, Tran Nancy, Su Trent, Van Christopher, Vashisht Ajay, Wohlschlegel James, Peterson Craig L, Timmers H T Marc, Kurdistani Siavash K, Carey Michael F
Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA.
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Mol Cell. 2017 Aug 17;67(4):594-607.e4. doi: 10.1016/j.molcel.2017.06.029. Epub 2017 Jul 20.
Pervasive transcription initiates from cryptic promoters and is observed in eukaryotes ranging from yeast to mammals. The Set2-Rpd3 regulatory system prevents cryptic promoter function within expressed genes. However, conserved systems that control pervasive transcription within intergenic regions have not been well established. Here we show that Mot1, Ino80 chromatin remodeling complex (Ino80C), and NC2 co-localize on chromatin and coordinately suppress pervasive transcription in S. cerevisiae and murine embryonic stem cells (mESCs). In yeast, all three proteins bind subtelomeric heterochromatin through a Sir3-stimulated mechanism and to euchromatin via a TBP-stimulated mechanism. In mESCs, the proteins bind to active and poised TBP-bound promoters along with promoters of polycomb-silenced genes apparently lacking TBP. Depletion of Mot1, Ino80C, or NC2 by anchor away in yeast or RNAi in mESCs leads to near-identical transcriptome phenotypes, with new subtelomeric transcription in yeast, and greatly increased pervasive transcription in both yeast and mESCs.
广泛转录起始于隐蔽启动子,在从酵母到哺乳动物的真核生物中均可观察到。Set2-Rpd3调控系统可防止已表达基因内的隐蔽启动子发挥作用。然而,控制基因间区域广泛转录的保守系统尚未完全确立。在此,我们表明Mot1、Ino80染色质重塑复合体(Ino80C)和NC2共定位于染色质上,并协同抑制酿酒酵母和小鼠胚胎干细胞(mESC)中的广泛转录。在酵母中,这三种蛋白质均通过Sir3刺激机制结合亚端粒异染色质,并通过TBP刺激机制结合常染色质。在mESC中,这些蛋白质与活性和准备就绪的TBP结合启动子以及明显缺乏TBP的多梳蛋白沉默基因的启动子结合。在酵母中通过锚定去除法或在mESC中通过RNAi去除Mot1、Ino80C或NC2会导致几乎相同的转录组表型,在酵母中出现新的亚端粒转录,在酵母和mESC中广泛转录均大幅增加。