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.

• Keywords
• RNA polymerase II CTD, Sen1 helicase, non-coding transcription, pervasive transcription, transcription termination,
• MeSH
• DNA Helicases chemistry   metabolism   MeSH
• RNA, Fungal metabolism   MeSH
• Protein Conformation MeSH
• Models, Molecular MeSH
• RNA, Untranslated metabolism   MeSH
• Protein Domains MeSH
• RNA-Binding Proteins chemistry   metabolism   MeSH
• Gene Expression Regulation, Fungal MeSH
• RNA Helicases chemistry   metabolism   MeSH
• RNA Polymerase II chemistry   MeSH
• Saccharomyces cerevisiae Proteins chemistry   metabolism   MeSH
• Saccharomyces cerevisiae genetics   metabolism   MeSH
• Transcription Termination, Genetic MeSH
• Protein Binding MeSH
• Binding Sites MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA Helicases MeSH
• RNA, Fungal MeSH
• RNA, Untranslated MeSH
• NRD1 protein, S cerevisiae MeSH Browser
• RNA-Binding Proteins MeSH
• RNA Helicases MeSH
• RNA Polymerase II MeSH
• Saccharomyces cerevisiae Proteins MeSH
• SEN1 protein, S cerevisiae MeSH Browser

Phosphorylation patterns of the C-terminal domain (CTD) of largest subunit of RNA polymerase II (called the CTD code) orchestrate the recruitment of RNA processing and transcription factors. Recent studies showed that not only serines and tyrosines but also threonines of the CTD can be phosphorylated with a number of functional consequences, including the interaction with yeast transcription termination factor, Rtt103p. Here, we report the solution structure of the Rtt103p CTD-interacting domain (CID) bound to Thr4 phosphorylated CTD, a poorly understood letter of the CTD code. The structure reveals a direct recognition of the phospho-Thr4 mark by Rtt103p CID and extensive interactions involving residues from three repeats of the CTD heptad. Intriguingly, Rtt103p's CID binds equally well Thr4 and Ser2 phosphorylated CTD A doubly phosphorylated CTD at Ser2 and Thr4 diminishes its binding affinity due to electrostatic repulsion. Our structural data suggest that the recruitment of a CID-containing CTD-binding factor may be coded by more than one letter of the CTD code.

• Keywords
• NMR, RNA processing, RNAPII CTD code, structural biology,
• MeSH
• Phosphorylation MeSH
• Transcription, Genetic MeSH
• Protein Kinases metabolism   MeSH
• Proteolysis MeSH
• RNA Polymerase II chemistry   metabolism   MeSH
• Saccharomyces cerevisiae Proteins chemistry   metabolism   MeSH
• Serine metabolism   MeSH
• Protein Structure, Tertiary MeSH
• Threonine chemistry   metabolism   MeSH
• Transcription Factors chemistry   metabolism   MeSH
• Tyrosine metabolism   MeSH
• Protein Binding MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Protein Kinases MeSH
• RNA Polymerase II MeSH
• Rtt103 protein, S cerevisiae MeSH Browser
• Saccharomyces cerevisiae Proteins MeSH
• Serine MeSH
• Threonine MeSH
• Transcription Factors MeSH
• Tyrosine MeSH