The 7SK/P-TEFb snRNP controls ultraviolet radiation-induced transcriptional reprogramming
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE147055 | GEO | 2021/03/30
REPOSITORIES: GEO
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Project description:RNAP II is frequently paused near gene promoters in mammals and its transition to productive elongation requires active recruitment of P-TEFb, a cyclin-dependent kinase for RNAP II and other key transcription elongation factors. A fraction of P-TEFb is sequestered in an inhibitory complex containing the 7SK noncoding RNA, but it has been unclear how P-TEFb is switched from the 7SK complex to RNAP II during transcription activation. We report that SRSF2 (also known as SC35, an SR splicing factor) is part of the 7SK complex assembled at gene promoters and plays a direct role in transcription pause release. We demonstrate RNA-dependent, coordinated release of SRSF2 and P-TEFb from the 7SK complex and transcription activation via SRSF2 binding to promoter-associated nascent RNA. These findings reveal an unanticipated SR protein function, a role for promoter-proximal nascent RNA in gene activation, and an analogous mechanism to HIV Tat/TAR for activating cellular genes. SR ChIP-seq, Pol II ChIP-seq, and Gro-seq
2013-05-09 | E-GEOD-45517 | biostudies-arrayexpress
Project description:The transition from transcription initiation into elongation at promoters of primary response genes (PRG) in metazoan cells is controlled by inducible transcription factors, which utilize P-TEFb to phosphorylate RNA Polymerase II (Pol II) in response to stimuli. Prior to stimulation, a fraction of P-TEFb is recruited to promoters in a catalytically inactive state bound to the 7SK small nuclear ribonucleoprotein (snRNP). However, it remains unclear how and why the 7SK snRNP is assembled at promoters. Here we report that the transcriptional regulator KAP1 directly recruits the 7SK snRNP to facilitate localized release of P-TEFb, promoting rapid Pol II elongation and PRG synthesis in response to stimuli. Collectively, we have discovered and characterized a novel complex, which we term the KEC, which dictates rapid and robust PRG induction upon stimuli.
2015-10-09 | GSE72622 | GEO
Project description:The dynamic phosphorylation process regulated by the positive transcription elongation factor b (P-TEFb), a CDK9-cyclin T heterodimer, is critical for transcription elongation of numerous mammalian genes. Most P-TEFb in cells are normally sequestered in the 7SK snRNP, and their release from this complex is well-controlled to maintain proper cell homeostasis and growth. The comprehensive profiling of CDK9 substrates is essential for understanding diverse functions of P-TEFb in controlling gene expression. Here, integrative proteomics methodologies are developed to globally identify the potential substrates of CDK9 in vivo. Our results show that the 7SK methylphosphate capping enzyme MePCE is directly phosphorylated by CDK9 within the 7SK snRNP, which is known to exhibit little kinase activity toward other known CDK9 substrates. Upon ultraviolet radiation, MePCE becomes phosphorylated, leading to the dissociation of 7SK snRNP and release of P-TEFb to activate transcription. Meanwhile, the phosphorylation of MePCE does not affect its methyltransferase activity toward 7SK RNA. Our data suggest that even though CDK9 in 7SK snRNP has little kinase activity toward external substrates, it can phosphorylate the snRNP integral component MePCE, which is required to release P-TEFb. This novel inside-to-outside mode of P-TEFb activation may serve as a critical checkpoint in regulating gene transcription under stressful conditions.
2024-07-03 | PXD053627 |
Project description:RNAP II is frequently paused near gene promoters in mammals and its transition to productive elongation requires active recruitment of P-TEFb, a cyclin-dependent kinase for RNAP II and other key transcription elongation factors. A fraction of P-TEFb is sequestered in an inhibitory complex containing the 7SK noncoding RNA, but it has been unclear how P-TEFb is switched from the 7SK complex to RNAP II during transcription activation. We report that SRSF2 (also known as SC35, an SR splicing factor) is part of the 7SK complex assembled at gene promoters and plays a direct role in transcription pause release. We demonstrate RNA-dependent, coordinated release of SRSF2 and P-TEFb from the 7SK complex and transcription activation via SRSF2 binding to promoter-associated nascent RNA. These findings reveal an unanticipated SR protein function, a role for promoter-proximal nascent RNA in gene activation, and an analogous mechanism to HIV Tat/TAR for activating cellular genes.
2013-05-09 | GSE45517 | GEO
Project description:DNA damage response (DDR) involves dramatic transcriptional alterations, the mechanisms of which remain obscure. Here we show that following DNA damage, the RNA-binding motif protein 7 (RBM7) stimulates RNA polymerase II (Pol II) elongation and increases cell viability by activating the positive transcription elongation factor b (P-TEFb). This is mediated by DNA damage-enhanced binding of RBM7 to 7SK, the scaffold of the 7SK small nuclear ribonucleoprotein (snRNP) that inhibits P-TEFb. As a result, P-TEFb relocates from 7SK snRNP to chromatin to activate transcription of key DDR genes and multiple classes of non-coding RNAs. By alleviating the inhibition of P-TEFb, RBM7 thus promotes Pol II elongation to activate a transcriptional response that is crucial for cell fate upon genotoxic insult. Our work highlights a novel paradigm in stress-dependent control of Pol II pause release, and offers the promise of combating cancer by RBM7 and P-TEFb antagonists in combination with established DNA damage-inducing chemotherapeutics.
2018-06-01 | E-MTAB-6475 | biostudies-arrayexpress
Project description:The P-TEFb complex promotes transcription elongation by releasing paused RNA polymerase II. P-TEFb itself is known to be inactivated through binding to the non-coding RNA 7SK but there is only limited information about mechanisms regulating their association. Here, we show that cells deficient in the RNA-binding protein hnRNP R, a known 7SK interactor, exhibit increased transcription due to phosphorylation of RNA polymerase II. Intriguingly, loss of hnRNP R promotes the release of P-TEFb from 7SK, accompanied by enhanced hnRNP A1 binding to 7SK. Additionally, we found that hnRNP R interacts with BRD4, and that hnRNP R depletion increases BRD4 binding to the P-TEFb component CDK9. Finally, CDK9 is stabilized upon loss of hnRNP R and its association with Cyclin K is enhanced. Together, our results indicate that hnRNP R negatively regulates transcription by modulating the activity and stability of the P-TEFb complex, exemplifying the multimodal regulation of P-TEFb by an RNA-binding protein.
2022-07-21 | GSE202720 | GEO
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
2016-02-01 | GSE69139 | GEO
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
2016-02-01 | GSE69142 | GEO
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
2016-02-01 | GSE69141 | GEO
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
2016-02-01 | GSE69140 | GEO