Project description:In Saccharomyces cerevisiae short non-coding RNA (ncRNA) generated by RNA Polymerase II (Pol II) are terminated by the NRD complex consisting of Nrd1, Nab3 and Sen1. We now show that Pcf11, a component of the cleavage and polyadenylation complex (CPAC), is generally required for NRD-dependent transcription termination through the action of its CTD interacting domain (CID). Pcf11 localizes downstream of Nrd1 on NRD terminators, and its recruitment depends on Nrd1. Furthermore mutation of the Pcf11 CID results in Nrd1 retention on chromatin, delayed degradation of ncRNA and restricts Pol II CTD Ser2 phosphorylation and Sen1-Pol II interaction. Finally, the pcf11-13 and sen1-1 mutant phenotypes are very similar as both accumulate RNA:DNA hybrids and display Pol II pausing downstream of NRD terminators. We predict a mechanism whereby Nrd1 and Pcf11 exchange on chromatin facilitates Pol II pausing and CTD Ser2-P phosphorylation. This in turn promotes Sen1 activity that is required for NRD-dependent transcription termination in vivo.
Project description:In Saccharomyces cerevisiae short non-coding RNA (ncRNA) generated by RNA Polymerase II (Pol II) are terminated by the NRD complex consisting of Nrd1, Nab3 and Sen1. We now show that Pcf11, a component of the cleavage and polyadenylation complex (CPAC), is generally required for NRD-dependent transcription termination through the action of its CTD interacting domain (CID). Pcf11 localizes downstream of Nrd1 on NRD terminators, and its recruitment depends on Nrd1. Furthermore mutation of the Pcf11 CID results in Nrd1 retention on chromatin, delayed degradation of ncRNA and restricts Pol II CTD Ser2 phosphorylation and Sen1-Pol II interaction. Finally, the pcf11-13 and sen1-1 mutant phenotypes are very similar as both accumulate RNA:DNA hybrids and display Pol II pausing downstream of NRD terminators. We predict a mechanism whereby Nrd1 and Pcf11 exchange on chromatin facilitates Pol II pausing and CTD Ser2-P phosphorylation. This in turn promotes Sen1 activity that is required for NRD-dependent transcription termination in vivo. ChIP-seq with antibody against pol II in wild type and Pcf11 mutants: Pcf11-2, Pcf11-9 and Pcf11-13 grown at 25C and 37C along with input samples
Project description:We report here the transcriptome-wide distribution of yeast Rpb2, Sen1, Nrd1 and Nab3 binding sites. These data sets provide highresolution definition of non-poly(A) terminators, identify novel genes regulated by attenuation of nascent transcripts close to the promoter, and demonstrate the widespread occurrence of Nrd1-bound 3'-antisense transcripts on genes that are poorly expressed. In addition, we show that Sen1 does not cross-link to many expected ncRNAs but surprisingly binds to pre-mRNA transcripts suggesting a role in 3' end formation and/or termination. Six samples by adaptation of PAR-ClIP procedure
Project description:We report here the transcriptome-wide distribution of yeast Rpb2, Sen1, Nrd1 and Nab3 binding sites. These data sets provide highresolution definition of non-poly(A) terminators, identify novel genes regulated by attenuation of nascent transcripts close to the promoter, and demonstrate the widespread occurrence of Nrd1-bound 3'-antisense transcripts on genes that are poorly expressed. In addition, we show that Sen1 does not cross-link to many expected ncRNAs but surprisingly binds to pre-mRNA transcripts suggesting a role in 3' end formation and/or termination.
Project description:Nrd1 and Nab3 are two yeast RNA binding proteins which have been shown to be involved in transcription termination of non poly(A) genes. We have used expression profiling of a Nab3 mutant to discover novel RNA targets of the Nrd1 and Nab3 transcription termination pathway. Failure to terminate RNA polymerase II by Nab3 leads to continued transcription well beyond the correct termination sites, altering the expression of adjacent downstream genes. Using this concept, our microarray uncovered the up-regulation of numerous genes that are located downstream of “cryptic unstable transcripts”, transcripts that are transcribed, terminated and rapidly degraded by Nrd1, Nab3, and the nuclear exosome. Keywords: yeast temperature sensitive mutant 25C vs 37C
Project description:Nrd1 and Nab3 are two yeast RNA binding proteins which have been shown to be involved in transcription termination of non poly(A) genes. We have used expression profiling of a Nab3 mutant to discover novel RNA targets of the Nrd1 and Nab3 transcription termination pathway. Failure to terminate RNA polymerase II by Nab3 leads to continued transcription well beyond the correct termination sites, altering the expression of adjacent downstream genes. Using this concept, our microarray uncovered the up-regulation of numerous genes that are located downstream of âcryptic unstable transcriptsâ, transcripts that are transcribed, terminated and rapidly degraded by Nrd1, Nab3, and the nuclear exosome. Experiment Overall Design: Four yeast total RNA samples where analyzed in this study. These RNAs come from two separate strains of yeast, each strain at either the permissive temperature (25C) or the non-permissive temperature (37C). One of these strains is a wild type strain of yeast used as a control. The other strain has a mutation in the Nab3 protein that confers temperature sensitivity at the non-permissive temperature of 37C. After two hours at the non-permissive temperature, we observe disruptions in the Nrd1/Nab3 transcription termination pathway and this is the scheme that we followed for our microarray experiment. Our goal was to observe the global expression changes after 2 hours without Nab3 function.
Project description:Termination of RNAPII transcription is associated with RNA 3â end formation. For coding genes, termination is initiated by the cleavage/polyadenylation machinery. In contrast, a majority of noncoding transcription events in S. cerevisiae do not rely on RNA cleavage for termination, but instead terminate via a pathway that requires the Nrd1-Nab3-Sen1 (NNS) complex. Here we show that the S. pombe ortholog of Nrd1, Seb1, does not function in NNS-like termination, but promotes polyadenylation site selection of coding and noncoding genes. We found that Seb1 associates with 3â end processing factors, is enriched at the 3â end of genes, and binds RNA motifs downstream of cleavage sites. Importantly, a deficiency in Seb1 resulted in widespread changes in 3â UTR length as a consequence of increased alternative polyadenylation. Given that Seb1 levels affected the recruitment of conserved 3â end processing factors, our findings indicate that the conserved RNA-binding protein Seb1 co-transcriptionally controls alternative polyadenylation. Two biological replicates of Seb1 and Control (parental strain) CRAC experiments
Project description:RNAPII is responsible for transcription of protein-coding genes and short, regulatory RNAs. In Saccharomyces cerevisiae, termination of RNAPII-transcribed RNAs ≤1000 bases requires the NNS complex (comprised of Nrd1, Nab3, and Sen1) processing by the exosome, and the nuclear specific catalytic subunit, Rrp6. It has been shown that Rrp6 interacts directly with Nrd1, but whether or not Rrp6 is required for NNS-dependent termination is unclear. Loss of Rrp6 function may result in extension (or inhibition of termination) of NNS-dependent transcripts, or Rrp6 may only function after the fact to carry out RNA 3’ end processing. Here, we performed in-depth differential expression analyses and compare RNA-sequencing data of transcript length and abundance in cells lacking RRP6 to previously published sequencing data measuring the length of RNAs in Nrd1-depleted cells. We find many transcripts that were defined as unterminated upon loss of Nrd1 activity are of similar length in rrp6Δ, and expression levels of downstream genes are significantly decreased. This suggests a similar transcription interference mechanism occurs in cells lacking either Nrd1 or Rrp6, supporting the hypothesis that Rrp6 activity is required for proper NNS termination in vivo. Four biological replicates each for deletion mutant (RRP6) and reference cells (WT)
Project description:Transcription termination is key to gene regulation as it prevents transcription interference with neighboring genes. In Saccharomyces cerevisiae, termination at protein-coding genes is coupled to the cleavage of the nascent transcript, while most non-coding RNA transcription relies on a cleavage-independent termination pathway involving Nrd1, Nab3 and the helicase Sen1 (NNS pathway). In both pathways, the recruitment of termination factors involves phosphorylated forms of the RNA polymerase II C-terminal domain (CTD) but the contribution of individual CTD residues was never systematically investigated. Here, we investigated the impact of mutating phosphorylation sites in the CTD on termination. We observed widespread termination defects at protein-coding genes in mutants for Ser2 or Thr4 but rare defects in Tyr1 mutants for this class of genes. Instead, mutating Tyr1, or its phosphatase Glc7, led to widespread termination defects at non-coding genes known to terminate via the NNS pathway. These defects can be suppressed by slowing down transcription, suggesting that Tyr1 mediates termination via the regulation of elongation or pausing. Our work redefines the role of Tyr1 in termination at protein-coding genes in budding yeast and highlights its key role in termination by the NNS pathway.
Project description:Transcription termination is key to gene regulation as it prevents transcription interference with neighboring genes. In Saccharomyces cerevisiae, termination at protein-coding genes is coupled to the cleavage of the nascent transcript, while most non-coding RNA transcription relies on a cleavage-independent termination pathway involving Nrd1, Nab3 and the helicase Sen1 (NNS pathway). In both pathways, the recruitment of termination factors involves phosphorylated forms of the RNA polymerase II C-terminal domain (CTD) but the contribution of individual CTD residues was never systematically investigated. Here, we investigated the impact of mutating phosphorylation sites in the CTD on termination. We observed widespread termination defects at protein-coding genes in mutants for Ser2 or Thr4 but rare defects in Tyr1 mutants for this class of genes. Instead, mutating Tyr1, or its phosphatase Glc7, led to widespread termination defects at non-coding genes known to terminate via the NNS pathway. These defects can be suppressed by slowing down transcription, suggesting that Tyr1 mediates termination via the regulation of elongation or pausing. Our work redefines the role of Tyr1 in termination at protein-coding genes in budding yeast and highlights its key role in termination by the NNS pathway.