Global Analysis of Short RNAs Reveals Widespread Promoter-Proximal Stalling and Arrest of Pol II
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ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE18643 | GEO | 2009/12/11
SECONDARY ACCESSION(S): PRJNA121575
REPOSITORIES: GEO
Similar Datasets
Project description:We developed a novel approach to isolate and characterize, at nucleotide-level resolution, the RNAs derived from RNA polymerase II (Pol II) in early elongation complexes. We find that high numbers of these short RNAs are not correlated with gene expression but instead are indicative of promoter-proximally stalled polymerase. High amounts of these short RNAs are generated from more than one third of all genes, indicating that Pol II stalls in the promoter-proximal region on global scale. We also find that the nucleotide composition of the initially transcribed sequence plays an important role in promoting transcriptional stalling and that early elongation complexes are highly susceptible to backtracking and arrest. Global analysis of RNAs produced by promoter-proximal Pol II.
2009-12-11 | E-GEOD-18643 | biostudies-arrayexpress
Project description:In addition to phosphodiester bond formation, RNA polymerase II has an RNA endonuclease activity, stimulated by TFIIS, which rescues complexes that have arrested and backtracked. We identified backtracking sites using mNET-seq in human cells expressing dominant-negative TFIIS (TFIISDN) that inhibits RNA cleavage and stabilizes backtracked complexes. Backtracking is most frequent within 2 kb of start sites, consistent with slow elongation early in transcription, and in 3’ flanking regions where termination is enhanced by TFIISDN. Inhibition of the rescue from backtracked pol II by TFIISDN impaired the escape from 5’ pause sites, the completion of long transcripts, and activation of stress-inducible genes. TFIISDN slowed elongation rates genome-wide by half as measured by sequencing nascent transcripts pulse labeled with Bromouridine (Bru-seq) and by anti-pol II ChIP-seq at time points after release of a DRB block. These results suggest that rescue of backtracked pol II by TFIIS is a major stimulus of elongation.
2018-11-30 | GSE120201 | GEO
Project description:Metazoan gene expression is often regulated after the recruitment of RNA polymerase II (Pol II) to promoters, through the controlled release of promoter-proximally paused Pol II into productive RNA synthesis. Despite the prevalence of paused Pol II, very little is known about the dynamics of these early elongation complexes or the fate of short transcription start site-associated (tss) RNAs they produce. Here, we demonstrate that paused elongation complexes can be remarkably stable, with half-lives exceeding 15 minutes at genes with inefficient pause release. Promoter-proximal termination by Pol II is infrequent and released tssRNAs are targeted for rapid degradation. Further, we provide evidence that the predominant tssRNA species observed are nascent RNAs held within early elongation complexes. We propose that stable pausing of polymerase provides a temporal window of opportunity for recruitment of factors to modulate gene expression and that the nascent tssRNA represents an appealing target for these interactions. This submission includes 13 raw data files. Four samples (chromatin, soluble, mock-treated, and Rrp40-depleted) are represented by two biological replicate raw data files, while five samples (cells, DMSO, FP, mock-treated + FP, and Rrp-40depleted + FP) are represented by single raw data files.
2013-10-31 | E-GEOD-49078 | biostudies-arrayexpress
Project description:Metazoan gene expression is often regulated after the recruitment of RNA polymerase II (Pol II) to promoters, through the controlled release of promoter-proximally paused Pol II into productive RNA synthesis. Despite the prevalence of paused Pol II, very little is known about the dynamics of these early elongation complexes or the fate of short transcription start site-associated (tss) RNAs they produce. Here, we demonstrate that paused elongation complexes can be remarkably stable, with half-lives exceeding 15 minutes at genes with inefficient pause release. Promoter-proximal termination by Pol II is infrequent and released tssRNAs are targeted for rapid degradation. Further, we provide evidence that the predominant tssRNA species observed are nascent RNAs held within early elongation complexes. We propose that stable pausing of polymerase provides a temporal window of opportunity for recruitment of factors to modulate gene expression and that the nascent tssRNA represents an appealing target for these interactions.
2013-10-31 | GSE49078 | GEO
Project description:RNA polymerase II (pol II) can backtrack during transcription elongation, exposing the 3’ end of nascent RNA. Nascent RNA sequencing can approximate the location of backtracking events that are quickly resolved; however, the extent and genome wide distribution of more persistent backtracking is unknown. Consequently, we developed a novel method to directly sequence backtracked RNA. Our data shows that pol II slides backwards more than 20 nucleotides in human cells and can persist in this backtracked state. Persistent backtracking mainly occurs where pol II pauses near promoters and intron-exon junctions, and is enriched in genes involved in translation, replication, and development, where gene expression is inhibited if these events are unresolved. Histone genes are highly prone to persistent backtracking, where the accumulation and resolution of such events is required for timely expression during cell division. These results demonstrate that persistent backtracking has the potential to affect diverse gene expression programs.
2024-02-10 | GSE235830 | GEO
Project description:The transition of RNA polymerase II (Pol II) from initiation to productive elongation is a central, regulated step in metazoan gene expression. At many genes, Pol II pauses stably in early elongation, remaining engaged with the 25-60 nucleotide-long nascent RNA for many minutes while awaiting signals for release into the gene body. However, a number of genes display highly unstable promoter Pol II, suggesting that paused polymerase terminates transcription at these promoters and releases a short, non-functional RNA. Here, we investigate the mechanisms driving Pol II instability and discover that the Integrator complex targets paused Pol II and terminates transcription at selected genes. Specifically, Integrator utilizes its RNA endonuclease activity to cleave nascent RNA and destabilize elongating polymerase. Our findings uncover a previously unappreciated mechanism of metazoan gene repression, wherein promoter paused Pol II is prevented from entering productive elongation through regulated termination.
2019-11-27 | GSE114467 | GEO
Project description:Spt5 is a highly conserved RNA polymerase II (Pol II)-associated pausing and elongation factor. However, its impact on global elongation and Pol II processivity in mammalian cells has not been clarified. Here, we show that depleting Spt5 in mouse embryonic fibroblasts (MEFs) does not cause global elongation defects or decreased elongation rates. Instead, in the absence of Spt5, a fraction of Pol II molecules are dislodged during elongation thus decreasing the number of Pol II complexes that complete the transcription cycle. Most strikingly, this decrease is restricted to a narrow window between 15-20 kb from the promoter, a distance which coincides with the stage where accelerating Pol II attains maximum elongation speed and processivity. Consequently, long genes show a greater dependency on Spt5 for optimal elongation efficiency and overall gene expression than short genes. We propose that an important role of Spt5 in mammalian elongation is to promote the processivity of those Pol II complexes that are transitioning towards maximum elongation speed 15-20 kb from the promoter.
2018-03-06 | GSE106313 | GEO
Project description:Alternative polyadenylation yields many mRNA isoforms whose 3’ termini occur disproportionately in clusters within 3’ UTRs. Profiles of poly(A) site usage are regulated by the rate of transcriptional elongation by RNA polymerase II (Pol II). Pol II derivatives with slow elongation rates confer an upstream-shifted poly(A) profile, whereas fast Pol II strains confer a downstream-shifted poly(A) profile. In yeast, upstream and downstream shifts within isoform clusters occur steadily at the nucleotide level. In contrast, changes from one isoform to the next are much smaller between clusters, even when the distances between them are relatively large. Pol II occupancy increases just downstream of the most speed-sensitive poly(A) sites, suggesting a linkage between reduced elongation rate and cluster formation. These observations suggest that 1) Pol II elongation speed affects the nucleotide-level dwell time allowing polyadenylation to occur, 2) poly(A) site clusters are linked to the local elongation rate and hence do not arise simply by intrinsically imprecise cleavage and polyadenylation of the RNA substrate, 3) DNA sequence elements can affect Pol II elongation and poly(A) profiles, and 4) the cleavage/polyadenylation and Pol II elongation complexes are spatially, and perhaps physically, coupled so that polyadenylation occurs rapidly upon emergence of the nascent RNA from the Pol II elongation complex.
2022-11-28 | GSE214095 | GEO
Project description:In bacteria, translation-transcription coupling inhibits RNA polymerase (RNAP) stalling. We present evidence suggesting that, upon amino acid starvation, inactive ribosomes promote rather than inhibit RNAP stalling. We developed an algorithm to evaluate genome-wide polymerase progression independently of local noise, and used it to reveal that the transcription factor DksA inhibits promoter-proximal pausing and increases RNAP elongation when uncoupled from translation by depletion of charged tRNAs. DksA has minimal effect on RNAP elongation in vitro and on untranslated RNAs in vivo. In these cases, transcripts can form RNA structures that prevent backtracking. Thus, the effect of DksA on transcript elongation may occur primarily upon ribosome slowing/stalling or at promoter-proximal locations that limit the potential for RNA structure. We propose that inactive ribosomes prevent formation of backtrackblocking mRNA structures and that, in this circumstance, DksA acts as a transcription elongation factor in vivo.
2014-04-21 | GSE54669 | GEO
Project description:Transcription-coupled DNA repair (TCR) efficiently removes bulky DNA lesions from transcribed parts of the genome and constitutes a major defence against DNA damage by UV irradiation. TCR begins when RNA polymerase II (Pol II) stalls at a DNA lesion and recruits the Cockayne syndrome protein CsB, the E3 ubiquitin ligase complex CRL4CsA, and the UV-stimulated scaffold protein A (UVSSA). Here we provide five high-resolution structures of Pol II transcription complexes with bound TCR factors and complementary biochemical data. Together with published work, our results converge on a model for the molecular mechanism of transcription-DNA repair coupling. In this model, Pol II stalling triggers the formation of an alternative transcription elongation complex that we call ECact. In ECact, CsB has replaced the elongation factor DSIF, binds the PAF1 complex, and repositions upstream DNA such that it contacts the elongation factor SPT6. The CsB translocase now pulls on the upstream DNA template, thereby pushing Pol II forward. If the lesion cannot be bypassed, Pol II gets stably stalled. CRL4CsA spans over the Pol II clamp to reach the Pol II jaw and direct ubiquitination of RPB1 residue lysine-1268. This triggers the recruitment of TFIIH to UVSSA, which is located at downstream DNA, and enables nucleotide excision repair. Finally, large-scale conformational changes in CRL4CsA enable ubiquitination of CsB and the release of TCR factors, thereby allowing Pol II to resume elongation and continue transcription over repaired DNA.
2022-02-17 | PXD025328 | Pride