Landscape of Transcription Termination in Arabidopsis Revealed by Single-molecule Nascent RNA Sequencing [FLEP-seq]
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE178980 | GEO | 2024/09/22
REPOSITORIES: GEO
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Project description:The dynamic process of transcription termination produces transient RNA intermediates, such as the full-length readthrough, 5’ and 3’ cleavage products, and polyadenylated nascent RNAs, which are difficult to distinguish from each other via short-read sequencing methods. Here, we used single-molecule nascent RNA sequencing to characterize these various forms of transient RNAs during termination at genome-wide scale in Arabidopsis. Our data revealed a wide range of termination windows (defined as the median readthrough distance) among genes, ranging from ~50 nt to over 1000 nt. The ends of termination windows precisely match the peak of Pol II occupancy and co-localize with termination factors. We also discovered a termination mechanism shaped by the downstream tRNA genes, suggesting that elongating Pol II can be expelled by Pol III activity. Mutation of the exonuclease AtXRN3 leads to a drastic accumulation of 3’ cleaved readthrough RNAs. Moreover, readthrough transcription in atxrn3 with delayed termination can run into downstream genes to produce normally spliced and polyadenylated mRNAs in the absence of their own transcription initiation. Our results revealed the diverse termination patterns in Arabidopsis, and our method is applicable to study the global termination landscape in a broad range of species.
2024-09-22 | GSE184099 | GEO
Project description:Using a modification of the yeast anchor away and PAR-CLIP protocols, we have mapped the position of Pol II genome-wide in living yeast cells after depletion of components of either the polyadenylation (pA) or non-pA termination complexes. Depletion of Ysh1 from the nucleus does not lead to readthrough transcription. In contrast, depletion of the termination factor Nrd1 leads to widespread runaway elongation of non-pA transcripts. Depletion of Sen1 also leads to readthrough at non-pA terminators but in contrast to Nrd1 this readthrough appears less processive. Examination of PAR-CLIP sequencing data of Pol II after removal of different transcriptional termination factors.
2014-07-24 | E-GEOD-56435 | biostudies-arrayexpress
Project description:Translation of mRNA into a polypeptide is terminated when the release factor eRF1 recognizes a UAA, UAG, or UGA stop codon in the ribosomal A site and stimulates nascent peptide release. However, stop codon readthrough can occur when a near-cognate tRNA outcompetes eRF1 in decoding the stop codon, resulting in the continuation of the elongation phase of protein synthesis. At the end of a conventional mRNA coding region readthrough allows translation into the mRNA 3’-UTR. Previous studies with reporter systems have shown that the efficiency of termination or readthrough is modulated by cis-acting elements other than stop codon identity, including two nucleotides 5’ of the stop codon, six nucleotides 3’ of the stop codon in the ribosomal mRNA channel, and stem-loop structures in the mRNA 3’-UTR. It is unknown whether these elements are important at a genome-wide level and whether other mRNA features proximal to the stop codon significantly affect termination and readthrough efficiencies in vivo. Accordingly, we carried out ribosome profiling analyses of yeast cells expressing wild-type or temperature-sensitive eRF1 and developed bioinformatics strategies to calculate readthrough efficiency, and to identify mRNA and peptide features which influence that efficiency. We found that the stop codon (nt +1 to +3), the nucleotide after it (nt +4), the codon in the P site (nt -3 to -1), and 3’-UTR length are the most influential features in the control of readthrough efficiency, while nts +5 to +9 and mRNA secondary structure in the 3’-UTR had milder effects. Additionally, we found low readthrough genes to have shorter 3’-UTRs compared to high readthrough genes in cells with thermally inactivated eRF1, while this trend was reversed in wild-type cells. Together, our results demonstrated the general roles of known regulatory elements in genome-wide regulation and identified several new mRNA or peptide features important for translation termination and readthrough.
2020-12-08 | GSE162780 | GEO
Project description:Transcription termination in Saccharomyces cerevisiae can be performed by at least two distinct pathways and is directed by the phosphorylation status of the carboxy-terminal domain (CTD) of RNA polymerase II (Pol II). Late termination of mRNAs is performed by the CPF/CF complex and requires CTD-Ser2 phosphorylation. Early termination of shorter cryptic unstable transcripts (CUTs) and small nucleolar RNAs (snoRNAs) is preformed by the Nrd1 complex, and requires CTD-Ser5 phosphorylation. In this study, mutants of the different termination pathways were compared by genome-wide expression analysis. Surprisingly, the expression changes observed upon loss of the CTD-Ser2 kinase Ctk1 are more similar to loss of a subunit of the Ser5P binding Nrd1-complex, than to loss of Ser2P binding factors. Tiling array analysis of ctk1Δ reveals readthrough at several hundred sites, including snoRNAs, as reported previously, but also many cryptic unstable transcripts, stable untranslated transcripts (SUTs) and other transcripts. Surprisingly, neither loss of CTK1 nor a Pol II CTD-Ser2 substitution mutant results in a global defect in termination of mRNAs, indicating that Ser2P is not essential for proper termination of most mRNAs. At snoRNA, Nrd1 location is shifted downstream in ctk1∆, indicating defective release rather than recruitment of Nrd1. Weakening the interaction between Nrd1 and Pol II rescues the readthrough in ctk1∆, likely by facilitating Nrd1 release. The termination defect is kinase activity dependent, but cannot be completely explained by loss of CTD-Ser2 phosphorylation , a major substrate of Ctk1, suggesting the involvement of an additional substrate. Mutant alleles of the elongation factor Spt5 rescue ctk1∆-dependent readthrough, indicating a role for Spt5 in this process, perhaps as a substrate of Ctk1. The results show that Ctk1 is more intimately involved in termination of small non-coding RNAs than was previously assumed and lead to a model in which Ctk1 influences Spt5 activity to achieve this.
2014-04-22 | GSE40254 | GEO
Project description:Transcription termination in Saccharomyces cerevisiae can be performed by at least two distinct pathways and is directed by the phosphorylation status of the carboxy-terminal domain (CTD) of RNA polymerase II (Pol II). Late termination of mRNAs is performed by the CPF/CF complex and requires CTD-Ser2 phosphorylation. Early termination of shorter cryptic unstable transcripts (CUTs) and small nucleolar RNAs (snoRNAs) is preformed by the Nrd1 complex, and requires CTD-Ser5 phosphorylation. In this study, mutants of the different termination pathways were compared by genome-wide expression analysis. Surprisingly, the expression changes observed upon loss of the CTD-Ser2 kinase Ctk1 are more similar to loss of a subunit of the Ser5P binding Nrd1-complex, than to loss of Ser2P binding factors. Tiling array analysis of ctk1Δ reveals readthrough at several hundred sites, including snoRNAs, as reported previously, but also many cryptic unstable transcripts, stable untranslated transcripts (SUTs) and other transcripts. Surprisingly, neither loss of CTK1 nor a Pol II CTD-Ser2 substitution mutant results in a global defect in termination of mRNAs, indicating that Ser2P is not essential for proper termination of most mRNAs. At snoRNA, Nrd1 location is shifted downstream in ctk1∆, indicating defective release rather than recruitment of Nrd1. Weakening the interaction between Nrd1 and Pol II rescues the readthrough in ctk1∆, likely by facilitating Nrd1 release. The termination defect is kinase activity dependent, but cannot be completely explained by loss of CTD-Ser2 phosphorylation , a major substrate of Ctk1, suggesting the involvement of an additional substrate. Mutant alleles of the elongation factor Spt5 rescue ctk1∆-dependent readthrough, indicating a role for Spt5 in this process, perhaps as a substrate of Ctk1. The results show that Ctk1 is more intimately involved in termination of small non-coding RNAs than was previously assumed and lead to a model in which Ctk1 influences Spt5 activity to achieve this. Two channel microarrays were used. RNA isolated from a large amount of wt yeast from a single culture was used as a common reference. This common reference was used in one of the channels for each hybridization and used in the statistical analysis to obtain an average expression-profile for each deletion mutant relative to the wt. Two independent cultures were hybridized on two separate microarrays. For the first hybridization the Cy5 (red) labeled cRNA from the deletion mutant is hybridized together with the Cy3 (green) labeled cRNA from the common reference. For the replicate hybridization, the labels are swapped. Each gene is represented twice on the microarray, resulting in four measurements per mutant. Using the Erlenmeyer growth protocol up to five deletion strains were grown on a single day. In the tecan platereader, up to eleven deletion strains could be grown on a single day. Wt cultures were grown parallel to the deletion mutants to assess day-to-day variance.
2014-04-22 | E-GEOD-40254 | biostudies-arrayexpress
Project description:Nascent RNA sequencing has recently revealed that pre-mRNA splicing can occur shortly after the intron emerges from RNA polymerase II (Pol II). Differences in co-transcriptional splicing profiles suggest regulation by cis- and/or trans-acting factors. Here we used Single Molecule Intron Tracking (SMIT) in budding yeast to identify a cohort of regulators by machine learning. One candidate, Nab2, displayed reduced co-transcriptional splicing of some pre-mRNAs when depleted. Unexpectedly, these splicing defects were attributable to readthrough transcription, which was revealed by long read sequencing of nascent RNA; individual readthrough transcripts induced by Nab2 depletion sometimes spanned multiple genes. Thus, Nab2 regulation of splicing was indirect. Moreover, unspliced transcripts displayed downstream readthrough in both control and Nab2-depleted cells, highlighting the coupling between splicing and 3′ end formation. We conclude that Nab2 is required for proper 3′ end processing, which ensures both transcription termination as well as proper splicing of downstream genes.
2020-10-27 | GSE156133 | GEO
Project description:Using a modification of the yeast anchor away and PAR-CLIP protocols, we have mapped the position of Pol II genome-wide in living yeast cells after depletion of components of either the polyadenylation (pA) or non-pA termination complexes. Depletion of Ysh1 from the nucleus does not lead to readthrough transcription. In contrast, depletion of the termination factor Nrd1 leads to widespread runaway elongation of non-pA transcripts. Depletion of Sen1 also leads to readthrough at non-pA terminators but in contrast to Nrd1 this readthrough appears less processive.
2014-07-24 | GSE56435 | GEO
Project description:We have generated single-nucleotide resolution, nascent transcription profiles from HeLa cells by developing Native Elongation Transcript sequencing technology for mammalian chromatin (mNET-seq). Our extensive data sets provide a substantial resource to study mammalian nascent transcript profiles. We reveal unanticipated phosphorylation states for RNA polymerase II C-terminal domain (Pol II CTD) at both gene ends. We also observe that following 5’ splice site cleavage by the spliceosome, upstream exon transcripts are tethered to Pol II CTD phosphorylated on the serine 5 position (S5P) which is accumulated over downstream exons. We further show that depletion of termination factors substantially reduces Pol II pausing at gene ends leading to termination defects. Remarkably termination factors play an additional promoter role by restricting non-productive RNA synthesis and redistributing Pol II CTD S2P to promoters. These data demonstrate that CTD phosphorylation is more dynamic and variably distributed across mammalian transcription units than previously envisaged. To monitor nascent RNA within the mammalian Pol II complex, and its association with different CTD phosphorylation states, we employed mNET-seq methodology on HeLa cells, complemented with direct sequencing of chromatin-bound RNA (ChrRNA-seq). mNET-seq was preformed using the antibodies 8WG16, CMA602, CMA603 and CMA601, which are specific for unphosphorylated CTD, Ser2 phosphorylation, Ser5 phosphorylation and all CTD isoforms, respectively. In another experiment, to evaluate the effect of transcription termination factors in nascent RNA production by Pol II, mNET-seq and complemented with ChrRNA-seq was preformed on HeLa cells transfected with siRNA against PTBP1, CPSF73, CstF64+CstF64tau or Xrn2, and the gene profiles were compared with profiles from HeLa transfected with siRNA for Luciferase generated by the same protocol.
2015-04-23 | E-GEOD-60358 | biostudies-arrayexpress
Project description:In Arabidopsis thaliana two nuclear 5'-3' exonucleases, XRN2 & 3, are involved in the degradation and processing of several classes of nuclear RNAs and in transcription termination of RNA polymerase II. The role of XRN3 in Pol II transcription termination is investigated by combining two different types of RNA-seq data for Col-0 background WT and xrn3-8 mutant A. thaliana seedlings. The data for the experiment comprises single molecule Direct RNA Sequencing of unamplified RNA (3x WT, 4x xrn3-8 mutant) and high-depth Illumina strand-specific short read sequencing of PCR amplified ribosomal-RNA depleted RNA (Illumina TruSeq stranded ribozero Plant kit, 3x WT, 3x xrm3-8 mutant). In the xrn3 mutant, these data reveal a widespread accumulation of non-coding intergenic transcripts (xrn3-associated transcripts - XATs) generated by Pol II read-through transcription that are usually polyadenylated and lack the 5' cap structure. This data highlights the important role of exoribonucleases in the torpedo mechanism of Pol II transcription termination and show that a global disturbance in this process significantly impacts both gene expression and transcriptome integrity.
2019-09-02 | E-MTAB-5137 | biostudies-arrayexpress
Project description:In Arabidopsis thaliana two nuclear 5'-3' exonucleases, XRN2 & 3, are involved in the degradation and processing of several classes of nuclear RNAs and in transcription termination of RNA polymerase II. The role of XRN3 in Pol II transcription termination is investigated by combining two different types of RNA-seq data for Col-0 background WT and xrn3-8 mutant A. thaliana seedlings. The data for the experiment comprises single molecule Direct RNA Sequencing of unamplified RNA (3x WT, 4x xrn3-8 mutant) and high-depth Illumina strand-specific short read sequencing of PCR amplified ribosomal-RNA depleted RNA (Illumina TruSeq stranded ribozero Plant kit, 3x WT, 3x xrm3-8 mutant). In the xrn3 mutant, these data reveal a widespread accumulation of non-coding intergenic transcripts (xrn3-associated transcripts - XATs) generated by Pol II read-through transcription that are usually polyadenylated and lack the 5' cap structure. This data highlights the important role of exoribonucleases in the torpedo mechanism of Pol II transcription termination and show that a global disturbance in this process significantly impacts both gene expression and transcriptome integrity.
2019-09-02 | E-MTAB-5132 | biostudies-arrayexpress