Hypoxia-induced CTCF mediates alternative splicing via coupling chromatin looping and RNA Pol II pause to promote EMT in breast cancer
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ABSTRACT:
PROVIDER: PRJNA895479 | ENA |
REPOSITORIES: ENA
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Project description:Cancer cells experiencing hypoxic stress employ epithelial-mesenchymal transition (EMT) to undergo metastasis through rewiring of the chromatin landscape, epigenetics and importantly alternative splicing. However, how hypoxia influences expression and genome-wide redistribution of CTCF is still not known. Here, we performed CTCF-ChIP-seq and CUT&RUN assay to analyze differential occupancy of CTCF in normoxic and hypoxic breast cancer cell line. We discovered that hypoxia-induced gain of CTCF occupancy across the genome regulates EMT in hypoxic cells. Specifically, we did 4C-seq experiments on COL5A1 (EMT associated gene) gene loci and showed that CTCF-mediated promoter-exon upstream looping regulates epigenetic mark mainly DNA demethylation at distal alternatively spliced exon 64 and regulates CTCF-mediated RNA Pol II pausing at COL5A1exon64A that decides the outcome of splicing to favor EMT under hypoxia. Overall, we uncover that hypoxia-induced differential CTCF occupancy across the genome is associated with gene expression and alternative splicing events related to cancer progression, similarly to the proposed model.
2024-12-31 | GSE216843 | GEO
Project description:In Arabidopsis, RNA Polymerase II (Pol II) often pauses within a few hundred base pairs downstream of the polyadenylation site, reflecting efficient transcriptional termination, but how such pause is regulated remains largely elusive. Here, we studied Pol II dynamics at gene 3’ end by combining comprehensive experiments with mathematical modelling. We generated high-resolution Ser2P Pol II positioning data specifically enriched at gene 3’ end and defined a 3’ end pause index (3’PI). The position but not the extent of the 3’ end pause correlates with termination window size. The 3’PI is not decreased but even mildly increased in the termination deficient mutant xrn3, indicating 3’ end pause is a regulatory step early during the termination and before XRN3 mediated RNA decay that releases the Pol II. Unexpectedly, 3’PI is closely associated with gene exon numbers and co-transcriptional splicing efficiency. Multiple exons genes often display stronger 3’ end pauses and more efficient on-chromatin splicing than genes with few exons. Chemical inhibition of splicing strongly reduces the 3’PI and disrupts its correlation with exon numbers but does not globally impact 3’ end readthrough levels. These results were further confirmed by fitting Pol II positioning data with a mathematical model, which enables the estimation of parameters that define Pol II dynamics. Our work highlights that the number of exons via co-transcriptional splicing is a major determinant of Pol II pausing levels at gene 3’ end in plants.
2023-05-27 | GSE205545 | GEO
Project description:Coupling of co-transcriptional splicing and 3’ end Pol II pause during termination in Arabidopsis
| PRJNA846305 | ENA
Project description:Distal enhancers characterized by H3K4me1 mark play critical roles in developmental and transcriptional programs. However, potential roles of specific distal regulatory elements in regulating RNA Polymerase II (Pol II) promoter-proximal pause release remain poorly investigated. Here we report that a unique cohort of jumonji C domain-containing protein 6 (JMJD6) and bromodomain-containing protein 4 (Brd4) co-bound distal enhancers, termed anti-pause enhancers (A-PEs), regulate promoter-proximal pause release of a large subset of transcription units via long-range interactions. Brd4-dependent JMJD6 recruitment on A-PEs mediates erasure of H4R3me2(s), which is directly read by 7SK snRNA, and decapping/demethylation of 7SK snRNA, ensuring the dismissal of the 7SKsnRNA/HEXIM inhibitory complex. The interactions of both JMJD6 and Brd4 with the P-TEFb complex permit its activation and pause release of regulated coding genes. The functions of JMJD6/ Brd4-associated dual histone and RNA demethylase activity on anti-pause enhancers have intriguing implications for these proteins in development, homeostasis and disease. All Gro-seq(s) were designed to reveal the transcriptional targets of JMJD6 and Brd4, and assess the role of JMJD6 and Brd4 in Pol II promoter-proximal pause release. All ChIP-seq(s) were designed to understand the unique features, associated molecular mechanisms and functions of the anti-pause enhancers (A-PEs) discovered in the current study.
2014-01-14 | E-GEOD-51633 | biostudies-arrayexpress
Project description:RNA polymerase II (Pol II) is generally paused at promoter-proximal regions in most metazoans, and based on in vitro studies, this function has been attributed to the negative elongation factor (NELF). Here, we show that upon rapid depletion of NELF, Pol II fails to be released into gene bodies, stopping instead around the +1 nucleosomal dyad-associated region. The transition to the 2nd pause region is independent of positive transcription elongation factor P-TEFb. During the heat shock response, Pol II is rapidly released from pausing at heat shock induced genes, while most genes are paused and transcriptionally downregulated during the heat shock response. We find that both aspects of the heat shock response remain intact upon NELF loss. We find that NELF depletion results in global loss of cap-binding complex from chromatin without global reduction of nascent transcript 5’ cap stability. Thus, our studies implicate NELF functioning in early elongation complexes distinct from Pol II pause-release.
2020-03-09 | GSE144786 | 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 5 protein-depletion approach, prominent release and a subsequent increase in mature transcripts, whereas long genes fail to yield mature transcripts due to a loss of processivity. Mechanistically, loss of SPT6 results in loss of PAF1 complex (PAF1C) from RNA Pol II, leading to NELF-bound RNA Pol II release into the gene bodies. Furthermore, SPT6 and/or PAF1 depletion impairs heat shock-induced pausing, pointing to a role for SPT6 in regulating RNA Pol II pause/release through the recruitment of PAF1C during the early elongation.
2022-08-09 | PXD033771 | Pride
Project description:Knowledge of how Mediator and TFIID crosstalk contributes to promoter-enhancer (P-E) communication is important for elucidating the mechanism of enhancer function. We conducted an shRNA knockdown screen in murine embryonic stem cells to identify the functional overlap between Mediator and TFIID subunits on gene expression. Auxin-inducible degrons were constructed for TAF12 and MED4, the subunits eliciting the greatest overlap. Degradation of TAF12 led to a dramatic genomewide decrease in gene expression accompanied by destruction of TFIID, loss of Pol II pre-initiation complex (PIC) at the promoter, and significantly decreased Mediator binding to promoters and enhancers. Interestingly, loss of the PIC elicited only a mild effect on P-E looping by Promoter Capture Hi-C (PCHi-C). Degradation of MED4 had a minor effect of Mediator integrity but led to a consistent 2-fold loss in gene expression, decreased binding of Pol II to Mediator, and decreased recruitment of Pol II to the promoters, but no effect on the other PIC components. PCHi-C revealed no consistent effect of Med4 degradation on P-E looping. Collectively, our data show that TAF12 and MED4 contribute mechanistically in different ways to P-E communication but neither factor appears to directly control P-E looping, thereby dissociating P-E communication from physical looping.
2021-07-22 | GSE178849 | GEO
Project description:Knowledge of how Mediator and TFIID crosstalk contributes to promoter-enhancer (P-E) communication is important for elucidating the mechanism of enhancer function. We conducted an shRNA knockdown screen in murine embryonic stem cells to identify the functional overlap between Mediator and TFIID subunits on gene expression. Auxin-inducible degrons were constructed for TAF12 and MED4, the subunits eliciting the greatest overlap. Degradation of TAF12 led to a dramatic genomewide decrease in gene expression accompanied by destruction of TFIID, loss of Pol II pre-initiation complex (PIC) at the promoter, and significantly decreased Mediator binding to promoters and enhancers. Interestingly, loss of the PIC elicited only a mild effect on P-E looping by Promoter Capture Hi-C (PCHi-C). Degradation of MED4 had a minor effect of Mediator integrity but led to a consistent 2-fold loss in gene expression, decreased binding of Pol II to Mediator, and decreased recruitment of Pol II to the promoters, but no effect on the other PIC components. PCHi-C revealed no consistent effect of Med4 degradation on P-E looping. Collectively, our data show that TAF12 and MED4 contribute mechanistically in different ways to P-E communication but neither factor appears to directly control P-E looping, thereby dissociating P-E communication from physical looping.
2021-07-22 | GSE178848 | GEO
Project description:Knowledge of how Mediator and TFIID crosstalk contributes to promoter-enhancer (P-E) communication is important for elucidating the mechanism of enhancer function. We conducted an shRNA knockdown screen in murine embryonic stem cells to identify the functional overlap between Mediator and TFIID subunits on gene expression. Auxin-inducible degrons were constructed for TAF12 and MED4, the subunits eliciting the greatest overlap. Degradation of TAF12 led to a dramatic genomewide decrease in gene expression accompanied by destruction of TFIID, loss of Pol II pre-initiation complex (PIC) at the promoter, and significantly decreased Mediator binding to promoters and enhancers. Interestingly, loss of the PIC elicited only a mild effect on P-E looping by Promoter Capture Hi-C (PCHi-C). Degradation of MED4 had a minor effect of Mediator integrity but led to a consistent 2-fold loss in gene expression, decreased binding of Pol II to Mediator, and decreased recruitment of Pol II to the promoters, but no effect on the other PIC components. PCHi-C revealed no consistent effect of Med4 degradation on P-E looping. Collectively, our data show that TAF12 and MED4 contribute mechanistically in different ways to P-E communication but neither factor appears to directly control P-E looping, thereby dissociating P-E communication from physical looping.
2021-07-22 | GSE178851 | GEO
Project description:Knowledge of how Mediator and TFIID crosstalk contributes to promoter-enhancer (P-E) communication is important for elucidating the mechanism of enhancer function. We conducted an shRNA knockdown screen in murine embryonic stem cells to identify the functional overlap between Mediator and TFIID subunits on gene expression. Auxin-inducible degrons were constructed for TAF12 and MED4, the subunits eliciting the greatest overlap. Degradation of TAF12 led to a dramatic genomewide decrease in gene expression accompanied by destruction of TFIID, loss of Pol II pre-initiation complex (PIC) at the promoter, and significantly decreased Mediator binding to promoters and enhancers. Interestingly, loss of the PIC elicited only a mild effect on P-E looping by Promoter Capture Hi-C (PCHi-C). Degradation of MED4 had a minor effect of Mediator integrity but led to a consistent 2-fold loss in gene expression, decreased binding of Pol II to Mediator, and decreased recruitment of Pol II to the promoters, but no effect on the other PIC components. PCHi-C revealed no consistent effect of Med4 degradation on P-E looping. Collectively, our data show that TAF12 and MED4 contribute mechanistically in different ways to P-E communication but neither factor appears to directly control P-E looping, thereby dissociating P-E communication from physical looping.
2021-07-22 | GSE178850 | GEO