Similar Datasets
Project description:Promoter distortion and opening in the RNA polymerase II cleft
| PRJNA438124 | ENA
Project description:Trimethylation of histone H3 lysine 4 (H3K4me3) is associated with transcriptional start sites and proposed to regulate transcription initiation. However, redundant functions of the H3K4 SET1/COMPASS methyltransferase complexes complicate elucidation of the specific role of H3K4me3 in transcriptional regulation. Here, by using mouse embryonic stem cells (mESCs) as a model system, we show that acute ablation of shared subunits of the SET1/COMPASS complexes leads to complete loss of all H3K4 methylation. H3K4me3 turnover occurs more rapidly than H3K4me1 and H3K4me2 and is dependent on KDM5 demethylases. Surprisingly, acute loss of H3K4me3 does not have detectable effects on transcriptional initiation but leads to a widespread decrease in transcriptional output, an increase in RNA polymerase II (RNAPII) pausing and slower elongation. Notably, we show that H3K4me3 is required for the recruitment of the Integrator Complex Subunit 11 (INTS11), which is essential for the eviction of paused RNAPII and transcriptional elongation. Thus, our study demonstrates a distinct role for H3K4me3 in transcriptional pause-release and elongation rather than transcriptional initiation.
2023-02-10 | PXD039176 | Pride
Project description:Trimethylation of histone H3 lysine 4 (H3K4me3) is associated with transcriptional start sites and proposed to regulate transcription initiation. However, redundant functions of the H3K4 SET1/COMPASS methyltransferase complexes complicate elucidation of the specific role of H3K4me3 in transcriptional regulation. Here, we show that acute ablation of shared subunits of the SET1/COMPASS complexes leads to complete loss of all H3K4 methylation. H3K4me3 turnover occurs more rapidly than H3K4me1 and H3K4me2 and is dependent on KDM5 demethylases. Surprisingly, acute loss of H3K4me3 does not have detectable effects on transcriptional initiation but leads to a widespread decrease in transcriptional output, an increase in RNA polymerase II (RNAPII) pausing and slower elongation. Our study demonstrates a distinct role for H3K4me3 in transcriptional pause-release and elongation rather than transcriptional initiation.
2023-03-14 | PXD028858 | Pride
Project description:Cyclin-dependent kinase 7 (CDK7), part of the general transcription factor TFIIH, promotes gene transcription by phosphorylating the C-terminal domain of RNA polymerase II (RNA Pol II). Here, we combine rapid CDK7 kinase inhibition with multi-omics analysis to unravel the direct functions of CDK7 in human cells. CDK7 inhibition causes RNA Pol II retention at promoters, leading to decreased RNA Pol II initiation and immediate global downregulation of transcript synthesis. Elongation, termination, and recruitment of co-transcriptional factors are not directly affected. Although RNA Pol II, initiation factors, and Mediator accumulate at promoters, RNA Pol II complexes can also proceed into gene bodies without promoter-proximal pausing while retaining initiation factors and Mediator. Further downstream, RNA Pol II phosphorylation increases and initiation factors and Mediator are released, allowing recruitment of elongation factors and an increase in RNA Pol II elongation velocity. Collectively, CDK7 kinase activity promotes the release of initiation factors and Mediator from RNA Pol II, facilitating RNA Pol II escape from the promoter.
2024-05-31 | PXD037842 | Pride
Project description:RNA polymerase II (pol II) transcribes all protein-coding and many non-coding RNAs in the human genome. Pol II transcription initiation is governed by the Pre-Initiation Complex (PIC), which contains TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, pol II, and Mediator. After initiation, pol II enzymes typically pause after transcribing less than 100 bases, and paused polymerases represent a common regulatory intermediate. Accordingly, paused pol II has been implicated in enhancer function, development and homeostasis, and diseases ranging from cancer to viral pathogenesis. Precisely how pol II promoter-proximal pausing is enforced and regulated remains unclear; however, protein complexes such as NELF and DSIF increase pausing whereas the activity of CDK9 (P-TEFb complex) correlates with pause release. To address specific mechanistic questions about pol II pausing and its regulation, we reconstituted human pol II promoter-proximal pausing in vitro, entirely with purified factors (no extracts). As expected, NELF and DSIF increased pol II pausing in vitro, whereas P-TEFb promoted pause release. Unexpectedly, the PIC alone was sufficient to reconstitute pol II pausing, suggesting that pausing is an inherent property of the PIC. In agreement, pol II pausing was lost upon replacement of the TFIID complex with TATA-binding protein (TBP); moreover, pausing was dependent upon TFIID subunits TAF1 and TAF2. TAF1/2 bind genomic DNA downstream of the pol II initiation site, invoking a “complex interaction” model for pausing. Consistent with this model, PRO-Seq experiments revealed increased transcription upon acute depletion (t=60 min) of TAF1 and TAF2 in human cells, and pol II pausing was disrupted at thousands of genes. Similar results were obtained in TAF1-depleted Drosophila S2 cells. Collectively, these data establish the general transcription factor TFIID as a genome-wide regulator of pol II promoter-proximal pausing.
2020-05-28 | GSE132764 | GEO
Project description:Transcription initiation is a highly regulated process that determines gene expression outcomes1,2, yet the dynamics and efficiency of individual initiation events in living cells remain poorly understood. Here we combine endogenous tagging of human RNA polymerase II (Pol II) and the TFIID subunit TAF1 with dual-color live-cell single-molecule imaging to quantitatively map Pol II behavior during transcription initiation and early elongation. Using GRID (Genuine Rate Identification) analysis, we resolved four kinetic populations of chromatin-bound Pol II and find that more than 94% of promoter-bound molecules dissociate within tens of seconds, indicating globally inefficient initiation. Kinetic partitioning of Pol II dwell times into promoter-proximal pausing and gene body elongation reveals a global pausing index that is selectively increased by CDK9 inhibition. Single-cell analysis uncovers substantial heterogeneity in initiation efficiency and pausing that is not explained by cell-cycle state. Spatial heatmap analysis identifies recurrent Pol II ‘hotspots’, nuclear regions enriched for repeated long-lived Pol II binding events, whose abundance and architecture are selectively perturbed by inhibitors that trap Pol II at promoters or disrupt TFIID. Finally, acute depletion of TAF1 leaves initiation efficiency unchanged but significantly increases the pausing index and reduces elongation efficiency, consistent with impaired pause release. Together, these findings establish a general framework to quantify transcription efficiency in vivo and support a model in which TAF1, and by extension TFIID, promotes pause release and productive elongation.
2026-06-03 | PXD072625 | Pride
Project description:Cyclin-dependent kinase 7 (CDK7), part of general transcription factor TFIIH, promotes gene transcription by phosphorylating the C-terminal domain of RNA polymerase II (Pol II). Here, we combine rapid CDK7 kinase inhibition with multi-omics analysis to unravel the direct functions of CDK7 in human cells. CDK7 inhibition causes Pol II retention at promoters, leading to decreased Pol II initiation and immediate global downregulation of transcript synthesis. Elongation, termination, and recruitment of co-transcriptional factors are not directly affected. Although Pol II, initiation factors, and Mediator accumulate at promoters, Pol II complexes can also proceed into gene bodies without promoter-proximal pausing while retaining initiation factors and Mediator. Further downstream, Pol II phosphorylation increases, initiation factors and Mediator are released, allowing recruitment of elongation factors and increase in Pol II elongation velocity. Collectively, CDK7 kinase activity promotes the release of initiation factors and Mediator from Pol II, facilitating Pol II escape from the promoter.
2024-06-01 | GSE218269 | GEO
Project description: Not available
| S-EPMC3414687 | biostudies-literature
Project description: Not available
| S-EPMC5777638 | biostudies-literature
Project description:RNA Polymerase II (Pol II) carries out transcription of both protein-coding and non-coding genes. Whereas Pol II initiation at protein-coding genes has been studied in detail, Pol II initiation at non-coding genes such as small nuclear RNA (snRNA) genes is not understood at the structural level. Here we study Pol II initiation at snRNA gene promoters and show that the snRNA-activating protein complex (SNAPc) enables DNA opening and transcription initiation independent of TFIIE and TFIIH in vitro. We then resolve cryo-EM structures of the SNAPc-containing Pol II preinitiation complex (PIC) assembled on U1 and U5 snRNA promoters. The core of SNAPc binds two turns of DNA and recognizes the snRNA promoter-specific proximal sequence element (PSE) located upstream of the TATA box-binding protein TBP. Two extensions of SNAPc called wing-1 and wing-2 bind TFIIA and TFIIB, respectively, explaining how SNAPc directs Pol II to snRNA promoters. Comparison of structures of closed and open promoter complexes elucidates TFIIH-independent DNA opening. These results provide the structural basis of Pol II initiation at non-coding RNA gene promoters.
2023-03-11 | PXD033638 | Pride