RNA helicase DDX21 coordinates transcription and noncoding RNA processing of the ribosomal pathway
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE56802 | GEO | 2014/11/17
SECONDARY ACCESSION(S): PRJNA244630
REPOSITORIES: GEO
Similar Datasets
Project description:DEAD-box RNA helicases are vital for the regulation of various aspects of the RNA life cycle, but the molecular underpinnings of their involvement, particularly in mammalian cells, remain poorly understood. Here we show that the DEAD-box RNA helicase DDX21 can sense transcriptional status of both RNA Pol I and Pol II to control transcriptional and post-transcriptional steps of ribosome biogenesis in human cells. We demonstrate that DDX21 widely associates with Pol I- and Pol II-transcribed genes and with diverse species of protein-coding and noncoding RNAs. Although broad, these molecular interactions, both at the chromatin and at the RNA level, exhibit a remarkable specificity for the ribosomal pathway. In the nucleolus, DDX21 occupies the transcribed rDNA locus, directly contacts both rRNA and snoRNAs and, as a functional component of the snoRNA ribonucleoprotein (snoRNP) complex, promotes modification of rRNA. In the nucleoplasm, DDX21 is incorporated into the 7SK snRNP complex, which facilitates DDX21 association with promoters of Pol II-transcribed genes encoding ribosomal proteins and snoRNAs. Promoter-bound DDX21 facilitates the release of P-TEFb from the 7SK snRNP, enhancing productive Pol II elongation. Altogether, we present a unifying mechanism for the coordinated regulation of ribosomal genes across nuclear compartments, and provide first evidence implicating a mammalian RNA helicase in RNA modification and Pol II elongation control. Examination of DDX21 chromatin association and DDX21 RNA interacting partners in HEK293 cells
2014-11-17 | E-GEOD-56802 | biostudies-arrayexpress
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 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: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
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 activation 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 that lead to DNA damage. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. In turn, 7SK occupancy at enhancers coincides with Brd4 and is exquisitely sensitive to the bromodomain inhibitor JQ1. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters.
2016-02-01 | GSE72599 | GEO
Project description:Myriad of craniofacial disorders are caused by heterozygous mutations in general regulators of housekeeping cellular functions such as ribosome biogenesis. While it is understood that many of these highly tissue-specific malformations are a consequence of defects in cranial neural crest cells (cNCCs), an embryonic cell group that gives rise to most of the facial structures during embryogenesis, the mechanism underlying cell type-selectivity of these effects remains largely unknown. Here we show that DDX21, a DEAD-box RNA helicase involved in control of both RNA polymerase (Pol) I and Pol II dependent transcriptional arms of ribosome biogenesis, is a key mediator of the nucleolar stress response. Using an in vitro model of Treacher Collins Syndrome (TCS), a craniofacial disorder caused by heterozygous mutations in components of the Pol I transcriptional machinery, we demonstrate that perturbations in ribosomal RNA (rRNA) transcription induce DDX21-mediated surveillance mechanism in cNCCs, leading to DDX21 relocalization from the nucleolus to the nucleoplasm, its eviction from Pol I and Pol II chromatin targets and inhibition of rRNA processing. Importantly, these effects are cell type-selective, cell-autonomous and involve activation of the p53 pathway. We further show that cNCCs are characterized by the inherently high reservoir of p53 mRNA and sensitivity to p53-mediated apoptosis. Remarkably, preventing the loss of DDX21 from nucleolus and chromatin can rescue both the sensitivity to apoptosis and TCS-associated craniofacial phenotypes in vivo. This mechanism is not restricted to TCS, as gene function perturbations linked to other ribosomopathies with craniofacial manifestations also lead to the activation of DDX21 surveillance. Lastly, we provide evidence that inhibition of rRNA synthesis leads to rDNA damage, and furthermore, that rDNA damage is sufficient to activate DDX21 surveillance and elicits tissue-selective and dosage-dependent effects on craniofacial development in vivo.
2018-02-01 | GSE89420 | GEO
Project description:Releasing promoter-proximally-paused RNA polymerase II (RNAPII) by the positive transcription elongation factor b (P-TEFb) is a central regulatory step of eukaryotic mRNA synthesis. The nuclear activity of P-TEFb is controlled mainly by the 7SK small nuclear RNP (snRNP) which sequesters active P-TEFb into inactive 7SK/P-TEFb snRNP. Here we demonstrate that under normal culture conditions, the lack of 7SK snRNP has only a minor impact on global RNAPII transcription and promoter-proximal pausing without detectable consequences on cell growth and proliferation. However, upon ultraviolet (UV) light-induced DNA damage, cells lacking 7SK have a defective transcriptional response and highly reduced viability. Both UV-induced release of ‘lesion-scanning’ polymerases and activation of key early responsive genes are compromised in the absence of 7SK. We show that proper induction of 7SK-dependent UV-responsive genes, namely efficient release of paused RNAPII and recruitment of key elongation factors, requires P-TEFb activity directly mobilized from the nucleoplasmic 7SK/P-TEFb snRNP.
2021-03-30 | GSE147055 | GEO