SPT6 functions in transcriptional pause/release via PAF1C recruitment
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap Elite
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: 
Byoung-Kyu Cho
LAB HEAD: Young Ah Goo
PROVIDER: PXD033771 | Pride | 2022-08-09
REPOSITORIES: Pride
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Project description:In vitro studies identified various factors including P-TEFb, SEC, SPT6, PAF1, DSIF, and NELF functioning at different stages of transcription elongation driven by RNA polymerase II (RNA Pol II). What remains unclear is how these factors cooperatively regulate pause/release and productive elongation in the context of living cells. Using an acute protein-depletion approach, we report that SPT6 depletion results in release of paused RNA Pol II. Short genes demonstrate a prominent release and a subsequent increase in mature transcripts, whereas long genes fail to yield mature transcripts due to a loss of processivity. Unexpectedly, the recruitment of PAF1 complex (PAF1C) to RNA Pol II fails upon SPT6 depletion, leading to the release of NELF-bound RNA Pol II into the gene bodies. Furthermore, SPT6 depletion impairs heat shock-induced pausing, pointing to a role for SPT6 in regulating RNA Pol II pause-release through PAF1C recruitment and NELF removal during the early elongation.
2022-08-09 | GSE202189 | GEO
Project description:In vitro studies identified various factors including P-TEFb, SEC, SPT6, PAF1, DSIF, and NELF functioning at different stages of transcription elongation driven by RNA polymerase II (RNA Pol II). What remains unclear is how these factors cooperatively regulate pause/release and productive elongation in the context of living cells. Using an acute protein-depletion approach, we report that SPT6 depletion results in release of paused RNA Pol II. Short genes demonstrate a prominent release and a subsequent increase in mature transcripts, whereas long genes fail to yield mature transcripts due to a loss of processivity. Unexpectedly, the recruitment of PAF1 complex (PAF1C) to RNA Pol II fails upon SPT6 depletion, leading to the release of NELF-bound RNA Pol II into the gene bodies. Furthermore, SPT6 depletion impairs heat shock-induced pausing, pointing to a role for SPT6 in regulating RNA Pol II pause-release through PAF1C recruitment and NELF removal during the early elongation.
2022-08-09 | GSE202187 | GEO
Project description:In vitro studies identified various factors including P-TEFb, SEC, SPT6, PAF1, DSIF, and NELF functioning at different stages of transcription elongation driven by RNA polymerase II (RNA Pol II). What remains unclear is how these factors cooperatively regulate pause/release and productive elongation in the context of living cells. Using an acute protein-depletion approach, we report that SPT6 depletion results in release of paused RNA Pol II. Short genes demonstrate a prominent release and a subsequent increase in mature transcripts, whereas long genes fail to yield mature transcripts due to a loss of processivity. Unexpectedly, the recruitment of PAF1 complex (PAF1C) to RNA Pol II fails upon SPT6 depletion, leading to the release of NELF-bound RNA Pol II into the gene bodies. Furthermore, SPT6 depletion impairs heat shock-induced pausing, pointing to a role for SPT6 in regulating RNA Pol II pause-release through PAF1C recruitment and NELF removal during the early elongation.
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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
Project description:Release of promoter-proximal paused RNA polymerase II (Pol II) during early elongation is a critical step in transcriptional regulation in metazoan cells. Paused Pol II release is thought to require the kinase activity of cyclin-dependent kinase 9 (CDK9) for the phosphorylation of DRB sensitivity-inducing factor, negative elongation factor, and C-terminal domain (CTD) serine-2 of Pol II. We found that Pol II-associated factor 1 (PAF1) is a critical regulator of paused Pol II release, that positive transcription elongation factor b (P-TEFb) directly regulates the initial recruitment of PAF1 complex (PAF1C) to genes, and that the subsequent recruitment of CDK12 is dependent on PAF1C. These findings reveal cooperativity among P-TEFb, PAF1C, and CDK12 in pausing release and Pol II CTD phosphorylation. Comparison of the chromatin occupancy of [1] PAF1, CDC73, LEO1, CTR9, total Pol II, and CTD serine 2-phosphorylated Pol II by ChIP-seq in THP1 cells; [2] PAF1, Pol II, Pol II (ser-5p), CDK12, and CDK9 by ChIP-seq in control and PAF1 knockdown cells; [3] LEO1 and Pol II by ChIP-seq in control and flavopiridol treated THP1 cells.
2015-12-11 | E-GEOD-62171 | biostudies-arrayexpress
Project description:Elongation factor Paf1C regulates several stages of the RNA polymerase II (Pol II) transcription cycle, although it is unclear how it modulates Pol II distribution and progression in mammalian cells. We found that conditional ablation of Paf1 resulted in the accumulation of unphosphorylated and Ser5 phosphorylated Pol II around promoter proximal regions and within the first 20-30 kb of gene bodies, respectively. Paf1 ablation did not impact the recruitment of other key elongation factors, namely, Spt5, Spt6, and the FACT complex, suggesting that Paf1 function may be mechanistically distinguishable from each of these factors. Moreover, loss of Paf1 triggered an increase in TSS-proximal nucleosome occupancy, which could impose a considerable barrier to Pol II elongation past TSS-proximal regions. Remarkably, accumulation of Ser5P in the first 20-30 kb coincided with reductions in histone H2B ubiquitylation within this region. Furthermore, we show that nascent RNA species accumulate within this window, suggesting a mechanism whereby Paf1 loss leads to aberrant, prematurely terminated transcripts and diminution of full-length transcripts. Importantly, we found that loss of Paf1 results in Pol II elongation rate defects with significant rate compression. Our findings suggest that Paf1C is critical for modulating Pol II elongation rates by functioning beyond the pause-release step as an "accelerator" over specific early gene body regions.
2019-06-28 | GSE116169 | GEO
Project description:The Paf1 complex (Paf1C) is a conserved transcription elongation factor that regulates transcription elongation efficiency, facilitates co-transcriptional histone modifications, and impacts molecular processes linked to RNA synthesis, such as polyA site selection. Coupling of the activities of Paf1C to transcription elongation requires its association with RNA polymerase II (Pol II). Mutational studies in yeast identified Paf1C subunits Cdc73 and Rtf1 as important mediators of Paf1C association with Pol II on active genes. While the interaction between Rtf1 and the general elongation factor Spt5 is relatively well-understood, the interactions involving Cdc73 have not been fully elucidated. Using a site-specific protein cross-linking strategy in yeast cells, we identified direct interactions between Cdc73 and two components of the Pol II elongation complex, the elongation factor Spt6 and the largest subunit of Pol II. Both of these interactions require the tandem SH2 domain of Spt6. We also show that Cdc73 and Spt6 can interact in vitro and that rapid depletion of Spt6 dissociates Paf1 from chromatin, altering patterns of Paf1C-dependent histone modifications genome-wide. These results reveal interactions between Cdc73 and the Pol II elongation complex and identify Spt6 as a key factor contributing to the occupancy of Paf1C at active genes in Saccharomyces cerevisiae.
2023-02-24 | GSE201436 | GEO
Project description:Gene expression in metazoans is regulated by RNA Polymerase II (Pol II) promoter-proximal pausing and its release. Previously, we identified that Pol II-associated factor 1 (PAF1) modulates the release of paused Pol II into productive elongation. Here, we find that PAF1 occupies transcriptional enhancers and restrains hyperactivation of a subset of these enhancers. Enhancer activation as the result of Paf1 loss releases Pol II from paused promoters of nearby PAF1 target genes. Knockout of PAF1-regulated enhancers attenuates the release of paused Pol II on PAF1 target genes without major interference in the establishment of pausing at their cognate promoters. Thus, a subset of enhancers can primarily modulate gene expression by controlling the release of paused Pol II in a PAF1-dependent manner.
2017-09-01 | GSE97527 | GEO
Project description:The control of promoter-proximal pausing and the release of RNA polymerase II (RNA Pol II) is a widely used mechanism for regulating gene expression in metazoans, especially for genes that respond to environmental and developmental cues. Here, we identify Pol II associated Factor 1 (PAF1) as a major regulator of promoter-proximal pausing. Knockdown of PAF1 leads to increased release of paused Pol II into gene bodies at thousands of genes. Genes with the highest levels of paused Pol II exhibit the largest redistribution of Pol II from the promoter-proximal region into the gene body in the absence of PAF1. PAF1 depletion results in increased nascent transcription and increased levels of phosphorylation of Pol II’s c-terminal domain on serine 2 (Ser2P). These changes can be explained by the recruitment of the Ser2P kinase Super Elongation Complex (SEC) effecting increased release of paused Pol II into productive elongation, thus establishing a novel function for PAF1 as a major regulator of pausing in metazoans. ChIP-seq of Pol II of different forms, SEC subunits, PAFc subunits and H2Bub in human cell lines targeted by PAF1 or scramble shRNA. ChIP-seq of total Pol II in HCT116 cells targeted by BRE1A or scramble shRNA. ChIP-seq of total Pol II in S2 cells targeted by Paf1 or LacZ RNAi. Total RNA-seq, nascent RNA-seq and GRO-seq in HCT116 cells targeted by PAF1 or scramble shRNA.
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Project description:We have previously shown that the RNA polymerase II (Pol II)-DSIF complex associates with the PAF1 complex (PAF), RTF1 and SPT6 to form an activated elongation complex in vitro. Here we investigate the mechanisms that these factors use to stimulate Pol II elongation in vivo. We combine rapid factor depletion from human cells with genome-wide analyses of changes in RNA synthesis and occupancy with engaged Pol II. Whereas depletion of PAF subunits has little effect on transcription in vivo, depletion of RTF1 or SPT6 strongly compromises RNA synthesis, albeit in fundamentally different ways. RTF1 depletion decreases Pol II velocity, whereas SPT6 depletion impairs Pol II progression through nucleosomes. These results show that distinct transcription elongation factors stimulate Pol II velocity and Pol II progression through chromatin in vivo. Our results also provide evidence for two distinct barriers to elongation at the beginning of genes, the promoter-proximal pause site and the +1 nucleosome.
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