Project description: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 risk that needs to be controlled to prevent the perturbation of gene expression. 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 characterize structurally 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 the recognition of the Ser5-phosphorylated form of the CTD by the N-terminal domain of Sen1. Furthermore, we find that the N-terminal and the C-terminal domains of Sen1 can mediate intra-molecular interactions. Our results shed light onto the network of protein-protein interactions that control termination of non-coding transcription by Sen1.
Project description:Here we report high-resolution analyses of transcribing RNAPIII in either a wild-type (WT) background , a sen1-3 mutant or a Sen1 auxin-inducible degron (AID) strain in which Sen1 can be rapidly depleted upon addition of the auxin analogue Indole-3-acetic acid (IAA). Sen1 is a well-characterized transcription termination factor for RNAPII-dependent genes in budding yeast. Here we show that the presence of three point mutations in sen1-3 that abrogate the interaction of Sen1 with RNAPIII, as well as the depletion of Sen1 provoke global transcription termination defects at RNAPIII-dependent genes. These results indicate that Sen1 is also a transcription termination factor for RNAPIII transcription units.
Project description:Here we report high-resolution analyses of transcribing RNAPIII in either a wild-type (WT) background or a sen1-3 mutant in the G1 phase of the cell cycle. The mutations in Sen1-3 prevent the interaction of Sen1 with both RNAPIII and the replisome, raising the question whether the role of Sen1 in RNAPIII transcription termination could depend on the association of Sen1 with the replisome. Our data show that in the G1 phase of the cell cycle, where the replisome is not assembled, the sen1-3 mutant also exhibits transcription termination defects at RNAPIII-dependent genes, as in asynchronous cells. This result indicates that the role of Sen1 in termination at RNAPIII-dependent genes is independent on the association of Sen1 with the replisome.
Project description: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 risk that needs to be controlled to prevent the perturbation of gene expression. 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 characterize structurally 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 the recognition of the Ser5-phosphorylated form of the CTD by the N-terminal domain of Sen1. Furthermore, we find that the N-terminal and the C-terminal domains of Sen1 can mediate intra-molecular interactions. Our results shed light onto the network of protein-protein interactions that control termination of non-coding transcription by Sen1.
Project description:Manuscript title: Modulated termination of non-coding transcription partakes in the regulation of gene expression Here we report high-resolution analyses of transcribing RNAPII in either a wild-type (WT) background or a sen1T1623E mutant, which harbours a substitution that mimics the phosphorylation at threonine 1623. Sen1 is a well-characterized transcription termination factor for RNAPII-dependent non-coding genes in budding yeast. Here we show that the T1623E phosphomimetic mutation induces moderate but widespread termination defects at target non-coding genes, strongly suggesting that phosphoryation at T1623 modulates negatively Sen1 transcription termination activity.
Project description:Here we report high-resolution analyses of transcribing RNAPIII in either a wild-type (WT) background or a Nrd1 auxin-inducible degron (AID) strain in which Nrd1 can be rapidly depleted upon addition of the auxin analogue Indole-3-acetic acid (IAA). Nrd1 functions together with Sen1 in transcription termination at RNAPII-dependent non-coding genes. Here we show that depletion of Nrd1 does not affect transcription termination at RNAPIII-dependent genes, indicating that Nrd1 is not an RNAPIII transcription termination factor.