Université de Paris, CNRS, Institut Jacques Monod, Paris, France.
Université Paris-Saclay, Yvette, France.
EMBO J. 2020 Apr 1;39(7):e101548. doi: 10.15252/embj.2019101548. Epub 2020 Feb 28.
Pervasive transcription is a widespread phenomenon leading to the production of a plethora of non-coding RNAs (ncRNAs) without apparent function. Pervasive transcription poses a threat to proper gene expression that needs to be controlled. In yeast, the highly conserved helicase Sen1 restricts pervasive transcription by inducing termination of non-coding transcription. However, the mechanisms underlying the specific function of Sen1 at ncRNAs are poorly understood. Here, we identify a motif in an intrinsically disordered region of Sen1 that mimics the phosphorylated carboxy-terminal domain (CTD) of RNA polymerase II, and structurally characterize its recognition by the CTD-interacting domain of Nrd1, an RNA-binding protein that binds specific sequences in ncRNAs. In addition, we show that Sen1-dependent termination strictly requires CTD recognition by the N-terminal domain of Sen1. We provide evidence that the Sen1-CTD interaction does not promote initial Sen1 recruitment, but rather enhances Sen1 capacity to induce the release of paused RNAPII from the DNA. Our results shed light on the network of protein-protein interactions that control termination of non-coding transcription by Sen1.
普遍转录是一种广泛存在的现象，导致产生大量无明显功能的非编码 RNA（ncRNA）。普遍转录对需要控制的正确基因表达构成威胁。在酵母中，高度保守的解旋酶 Sen1 通过诱导非编码转录的终止来限制普遍转录。然而，Sen1 在 ncRNA 上的特定功能的机制尚不清楚。在这里，我们在 Sen1 的一个固有无序区域中鉴定出一个模拟 RNA 聚合酶 II 磷酸化羧基末端结构域（CTD）的基序，并对其结构进行了表征，该基序由 RNA 结合蛋白 Nrd1 的 CTD 相互作用结构域识别，该蛋白结合 ncRNA 中的特定序列。此外，我们表明 Sen1 依赖性终止严格要求 Sen1 通过 N 末端结构域识别 CTD。我们提供的证据表明，Sen1-CTD 相互作用不会促进 Sen1 的初始募集，而是增强 Sen1 从 DNA 上释放暂停的 RNAPII 的能力。我们的研究结果阐明了控制 Sen1 终止非编码转录的蛋白质-蛋白质相互作用网络。
