The role of Mediator and Little Elongation Complex in transcription termination
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ABSTRACT:
PROVIDER: PRJNA495373 | ENA |
REPOSITORIES: ENA
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Project description:Mediator is a coregulatory complex involved in regulating the transcription of Pol II-dependent genes. Metazoan Mediator subunit MED26 functions as a docking site for the ELL/EAF-containing Super Elongation Complex (SEC) and L ittle Elongation Complex (LEC), which regulate the expression of distinct genes. MED26 helps to recruit SEC to protein-coding genes including c-Myc and LEC to small nuclear RNA (snRNA) genes. However, why MED26 takes advantage of SEC or LEC to regulate different claases of genes is unclear. Here, we present evidence that MED26 recruits LEC to support optimal transcription termination at non-polyadenylated genes including snRNA and replication-dependent histone (RDH) genes. Our findings indicate that LEC recruited by MED26 promotes efficient transcription termination by Pol II through interaction with CBC-ARS2 and NELF/DSIF, and then LEC promotes 3’-end processing through the recruitment of Integrator or Heat labile factor to snRNA or RDH genes, respectively.
2020-01-21 | GSE121024 | GEO
Project description:Mediator is a coregulatory complex that regulates transcription of Pol II-dependent genes. Previously, we showed that human Mediator subunit MED26 plays a role in the recruitment of Super Elongation Complex (SEC) or Little Elongation Complex (LEC) to regulate the expression of certain genes. MED26 plays a role in recruiting SEC to protein-coding genes including c-myc and LEC to small nuclear RNA (snRNA) genes. However, how MED26 engages SEC or LEC to regulate distinct genes is unclear. Here, we provide evidence that MED26 recruits LEC to modulate transcription termination of non-polyadenylated transcripts including snRNAs and mRNAs encoding replication-dependent histone (RDH) at Cajal bodies. Our findings indicate that LEC recruited by MED26 promotes efficient transcription termination by Pol II through interaction with CBC-ARS2 and NELF/DSIF, and promotes 3' end processing by enhancing recruitment of Integrator or Heat Labile Factor to snRNA or RDH genes, respectively.
| S-EPMC7044329 | biostudies-literature
Project description:The Eleven-nineteen Lysine-rich Leukemia (ELL)-containing Super Elongation Complex (SEC) containing P-TEFb is a key regulator in the expression of HOX genes in Mixed Lineage Leukemia (MLL)-based leukemia. We have identified an SEC-like complex in Drosophila, as well as a distinct ELL-containing complex that lacks P-TEFb and other components of SEC named the "little elongation complex" (LEC). LEC subunits are highly enriched at RNA Polymerase II (Pol II) transcribed small nuclear RNA (snRNA) genes and the loss of LEC results in decreased snRNA expression in both flies and mammals. The discovery of specificity of SEC and LEC complexes for mRNA and snRNA containing genes, respectively, suggest the presence of specific classes of elongation factors for each class of genes transcribed by RNA polymerase II. Examination of genome-wide binding profiles for ELL, Ice1, Lilli, and Pol II in D. melanogaster and by ChIP-seq. Identification of differentially expressed genes in ELL-RNAi and Ice1-RNAi in D. melanogaster by RNA-seq. Examination of genome-wide binding profiles for ELL in M. musculus. Identification of differentially expressed genes in ELL-RNAi in M. musculus by RNA-seq.
2011-12-22 | E-GEOD-32120 | biostudies-arrayexpress
Project description:The Eleven-nineteen Lysine-rich Leukemia (ELL)-containing Super Elongation Complex (SEC) containing P-TEFb is a key regulator in the expression of HOX genes in Mixed Lineage Leukemia (MLL)-based leukemia. We have identified an SEC-like complex in Drosophila, as well as a distinct ELL-containing complex that lacks P-TEFb and other components of SEC named the "little elongation complex" (LEC). LEC subunits are highly enriched at RNA Polymerase II (Pol II) transcribed small nuclear RNA (snRNA) genes and the loss of LEC results in decreased snRNA expression in both flies and mammals. The discovery of specificity of SEC and LEC complexes for mRNA and snRNA containing genes, respectively, suggest the presence of specific classes of elongation factors for each class of genes transcribed by RNA polymerase II.
2011-12-22 | GSE32120 | GEO
Project description:Termination of RNA polymerase II (Pol II) transcription is a key step, that is important for 3’end formation of functional mRNA, mRNA release and Pol II recycling. Even so, this underlying termination mechanism is not yet understood. Here, we demonstrate that the conserved and essential termination factor Seb1 interacts with Pol II near the end of the RNA exit channel and the Rpb4/7 stalk. Furthermore, the Seb1 interaction surface with Pol II largely overlaps with that of the elongation factor Spt5. Notably, Seb1 co-transcriptional recruitment is dependent on Spt5 de-phosphorylation by the conserved PP1 phosphatase Dis2, which also de-phosphorylates threonine 4 within the Pol II heptad repeated C-terminal domain. We propose that Dis2 orchestrates the transition from elongation to termination phase during the transcription cycle by mediating elongation to termination factor exchange and de-phosphorylation of Pol II C-terminal domain.
2018-12-26 | GSE111326 | GEO
Project description:The little elongation complex (LEC) regulates small nuclear RNA transcription
| PRJNA147449 | ENA
Project description:Elongation/termination factor exchange mediated by PP1 phosphatase orchestrates trancription termination
| PRJNA436595 | ENA
Project description:Transcription termination was analyzed by anti RNA pol II ChIP-seq in isogenic human HEK293 cell lines that inducibly express a-amanitin resistant mutants of the RNA polymerase II large subunit with slow and fast elongation rates and in lines that inducbily over-express WT or an active site mutant of the RNA exonuclease "torpedo" Xrn2. Transcription termination zones were mapped by anti-pol II ChIP-seq under conditions where transcription elongation rate was increased or decreased by point mutations in the large subunit of the enzyme. Termination was also assayed under conditions where Xrn2 exonuclease activity was inhibited by over-expression of an active site mutant (D235A).
2015-11-19 | E-GEOD-72800 | biostudies-arrayexpress
Project description:The transcription factor T-bet directs Th1 cell differentiation, but the molecular mechanisms that underlie this lineage-specific gene regulation are not completely understood. Here, we show that T-bet acts through super-enhancers in human and mouse Th1 cells to recruit Mediator and P-TEFb in the form of the super elongation complex (SEC). Th1-specific genes are poised in Th2 cells while T-bet-mediated recruitment of P-TEFb in Th1 cells activates transcriptional elongation. P-TEFb is recruited to both genes and super-enhancers, where it activates enhancer RNA transcription. P-TEFb inhibition and Mediator and SEC knockdown selectively block activation of T-bet target genes and P-TEFb inhibition abrogates Th1-associated experimental autoimmune uveitis. T-bet activity is independent of changes in NF-κB RelA and Brd4 binding, but T-bet- and NF-κB-mediated pathways converge to allow P-TEFb recruitment. These data support a model in which lineage-specifying factors allow recruitment of P-TEFb to poised genes to promote differentiation of alternative T cell fates.
2016-06-08 | GSE62482 | GEO
Project description:SPT6 is both, an important histone chaperone and POL2 elongation factor but its primary role on transcription in mammalian cells remains open, as no acute depletion system is available. We used targeted protein degradation to rapidly deplete SPT6 and analyzed defects in POL2 behavior by a multi-omics approach and estimated POL2 processivity, elongation rates and termination and compared it to gene transcription. Our data indicate that SPT6 is a crucial factor for POL2 elongation. Unexpectedly, SPT6 has also a vital role in POL2 termination, as acute depletion induces POL2 read through at most protein coding genes. In contrast, acute depletion did not induce spurious intragenic initiation, while this behavior can be induced by long-term depletion of SPT6 and can therefore be attributed to its function as a histone chaperone. In conclusion, targeted protein degradation of SPT6 allows the kinetic discrimination of its function as a histone chaperone and POL2 elongation factor.
2021-06-23 | GSE162264 | GEO