scholarly journals P-TEFb activation by RBM7 shapes a pro-survival transcriptional response to genotoxic stress

2018 ◽  
Author(s):  
Andrii Bugai ◽  
Alexandre J.C. Quaresma ◽  
Caroline C. Friedel ◽  
Tina Lenasi ◽  
Christopher R. Sibley ◽  
...  
Keyword(s):  
Dna Damage ◽  
Rna Polymerase Ii ◽  
Cell Fate ◽  
Rna Binding ◽  
Transcriptional Response ◽  
Genotoxic Stress ◽  
Binding Motif ◽  
Pol Ii ◽  
Small Nuclear Ribonucleoprotein ◽  
Stress Dependent

SUMMARYCellular DNA damage response (DDR) involves dramatic transcriptional alterations, the mechanisms of which remain ill-defined. Given the centrality of RNA polymerase II (Pol II) promoter-proximal pause release in transcriptional control, we evaluated its importance in DDR. Here we show that following genotoxic stress, the RNA-binding motif protein 7 (RBM7) stimulates Pol II elongation and promotes cell viability by activating the positive transcription elongation factor b (P-TEFb). This is mediated by genotoxic stress-enhanced binding of RBM7 to 7SK snRNA (7SK), the scaffold of the 7SK small nuclear ribonucleoprotein (7SK snRNP) which inhibits P-TEFb. In turn, P-TEFb relocates from 7SK snRNP to chromatin to induce transcription of short units including key DDR genes and multiple classes of non-coding RNAs. Critically, interfering with RBM7 or P-TEFb provokes cellular hypersensitivity to DNA damage-inducing agents through activation of apoptotic program. By alleviating the inhibition of P-TEFb, RBM7 thus facilitates Pol II elongation to enable a pro-survival transcriptional response that is crucial for cell fate upon genotoxic insult. Our work uncovers a new paradigm in stress-dependent control of Pol II pause release, and offers the promise for designing novel anti-cancer interventions using RBM7 and P-TEFb antagonists in combination with DNA-damaging chemotherapeutics.

scholarly journals Continuous transcription initiation guarantees robust repair of transcribed genes and regulatory regions in response to DNA damage

2019 ◽  
Author(s):  
Anastasios Liakos ◽  
Dimitris Konstantopoulos ◽  
Matthieu D. Lavigne ◽  
Maria Fousteri
Keyword(s):  
Dna Damage ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
De Novo ◽  
Transcriptional Response ◽  
Genotoxic Stress ◽  
Chromatin Accessibility ◽  
Initiation Rate ◽  
Pol Ii ◽  
Active Genes

ABSTRACTInhibition of RNA synthesis caused by DNA damage-impaired RNA polymerase II (Pol II) elongation is found to conceal a local increase in de novo transcription, slowly progressing from Transcription Start Sites (TSSs) to gene ends. Although associated with accelerated repair of Pol II-encountered lesions and limited mutagenesis, it is still unclear how this mechanism is maintained during recovery from genotoxic stress. Here we uncover a surprising widespread gain in chromatin accessibility and preservation of the active histone mark H3K27ac after UV-irradiation. We show that the concomitant increase in Pol II release from promoter-proximal pause (PPP) sites of most active genes, PROMoter uPstream Transcripts (PROMPTs) and enhancer RNAs (eRNAs) favors unrestrained initiation, as demonstrated by the synthesis of short nascent RNAs, including TSS-associated RNAs (start-RNAs). In accordance, drug-inhibition of the transition into elongation replenished the post-UV reduced levels of pre-initiating pol II at TSSs. Continuous engagement of new Pol II thus ensures maximal transcription-driven DNA repair of active genes and non-coding regulatory loci. Together, our results reveal an unanticipated layer regulating the UV-triggered transcriptional-response and provide physiologically relevant traction to the emerging concept that transcription initiation rate is determined by pol II pause-release dynamics.

scholarly journals Regulation of integrin and extracellular matrix genes by HNRNPL is necessary for epidermal renewal

PLoS Biology ◽  
2021 ◽  
Vol 19 (9) ◽  
pp. e3001378
Author(s):  
Jingting Li ◽  
Yifang Chen ◽  
Manisha Tiwari ◽  
Varun Bansal ◽  
George L. Sen
Keyword(s):  
Stem Cells ◽  
Extracellular Matrix ◽  
Rna Polymerase Ii ◽  
Cell Fate ◽  
Progenitor Cell ◽  
Rna Binding ◽  
Critical Role ◽  
Basal Layer ◽  
Pol Ii ◽  
Progenitor Cell Proliferation

Stratified epithelia such as the epidermis require coordinated regulation of stem and progenitor cell proliferation, survival, and differentiation to maintain homeostasis. Integrin-mediated anchorage of the basal layer stem cells of the epidermis to the underlying dermis through extracellular matrix (ECM) proteins is crucial for this process. It is currently unknown how the expression of these integrins and ECM genes are regulated. Here, we show that the RNA-binding protein (RBP) heterogeneous nuclear ribonucleoprotein L (HNRNPL) binds to these genes on chromatin to promote their expression. HNRNPL recruits RNA polymerase II (Pol II) to integrin/ECM genes and is required for stabilizing Pol II transcription through those genes. In the absence of HNRNPL, the basal layer of the epidermis where the stem cells reside prematurely differentiates and detaches from the underlying dermis due to diminished integrin/ECM expression. Our results demonstrate a critical role for RBPs on chromatin to maintain stem and progenitor cell fate by dictating the expression of specific classes of genes.

scholarly journals Intracellular Localization of Hepatitis Delta Virus Proteins in the Presence and Absence of Viral RNA Accumulation

2009 ◽  
Vol 83 (13) ◽  
pp. 6457-6463 ◽  
Author(s):  
Ziying Han ◽  
Carolina Alves ◽  
Severin Gudima ◽  
John Taylor
Keyword(s):  
Rna Polymerase Ii ◽  
Protein Function ◽  
Hepatitis Delta Virus ◽  
Rna Binding ◽  
Intracellular Localization ◽  
Genome Replication ◽  
Hepatitis Delta ◽  
Pol Ii ◽  
Presence And Absence ◽  
Delta Virus

ABSTRACT Hepatitis delta virus (HDV) encodes one protein, hepatitis delta antigen (δAg), a 195-amino-acid RNA binding protein essential for the accumulation of HDV RNA-directed RNA transcripts. It has been accepted that δAg localizes predominantly to the nucleolus in the absence of HDV genome replication while in the presence of replication, δAg facilitates HDV RNA transport to the nucleoplasm and helps redirect host RNA polymerase II (Pol II) to achieve transcription and accumulation of processed HDV RNA species. This study used immunostaining and confocal microscopy to evaluate factors controlling the localization of δAg in the presence and absence of replicating and nonreplicating HDV RNAs. When δAg was expressed in the absence of full-length HDV RNAs, it colocalized with nucleolin, a predominant nucleolar protein. With time, or more quickly after induced cell stress, there was a redistribution of both δAg and nucleolin to the nucleoplasm. Following expression of nonreplicating HDV RNAs, δAg moved to the nucleoplasm, but nucleolin was unchanged. When δAg was expressed along with replicating HDV RNA, it was found predominantly in the nucleoplasm along with Pol II. This localization was insensitive to inhibitors of HDV replication, suggesting that the majority of δAg in the nucleoplasm reflects ribonucleoprotein accumulation rather than ongoing transcription. An additional approach was to reevaluate several forms of δAg altered at specific locations considered to be essential for protein function. These studies provide evidence that δAg does not interact directly with either Pol II or nucleolin and that forms of δAg which support replication are also capable of prior nucleolar transit.

scholarly journals DNA damage shifts circadian clock time via Hausp-dependent Cry1 stabilization

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Stephanie J Papp ◽  
Anne-Laure Huber ◽  
Sabine D Jordan ◽  
Anna Kriebs ◽  
Madelena Nguyen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Circadian Clock ◽  
Transcriptional Response ◽  
Genotoxic Stress ◽  
Genomic Integrity ◽  
Clock Time ◽  
Dna Repair Enzymes ◽  
Repair Enzymes ◽  
Specific Protease

The circadian transcriptional repressors cryptochrome 1 (Cry1) and 2 (Cry2) evolved from photolyases, bacterial light-activated DNA repair enzymes. In this study, we report that while they have lost DNA repair activity, Cry1/2 adapted to protect genomic integrity by responding to DNA damage through posttranslational modification and coordinating the downstream transcriptional response. We demonstrate that genotoxic stress stimulates Cry1 phosphorylation and its deubiquitination by Herpes virus associated ubiquitin-specific protease (Hausp, a.k.a Usp7), stabilizing Cry1 and shifting circadian clock time. DNA damage also increases Cry2 interaction with Fbxl3, destabilizing Cry2. Thus, genotoxic stress increases the Cry1/Cry2 ratio, suggesting distinct functions for Cry1 and Cry2 following DNA damage. Indeed, the transcriptional response to genotoxic stress is enhanced in Cry1−/− and blunted in Cry2−/− cells. Furthermore, Cry2−/− cells accumulate damaged DNA. These results suggest that Cry1 and Cry2, which evolved from DNA repair enzymes, protect genomic integrity via coordinated transcriptional regulation.

scholarly journals Regulation of Pkc1 Hyper-Phosphorylation by Genotoxic Stress

2021 ◽  
Vol 7 (10) ◽  
pp. 874
Author(s):  
Li Liu ◽  
Jiri Veis ◽  
Wolfgang Reiter ◽  
Edwin Motari ◽  
Catherine E. Costello ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Wall ◽  
Protein Kinase ◽  
Transcriptional Response ◽  
Genotoxic Stress ◽  
Telomere Maintenance ◽  
Phosphorylation Sites ◽  
Casein Kinase 1 ◽  
Checkpoint Kinases ◽  
Radiation Repair

The cell wall integrity (CWI) signaling pathway is best known for its roles in cell wall biogenesis. However, it is also thought to participate in the response to genotoxic stress. The stress-activated protein kinase Mpk1 (Slt2, is activated by DNA damaging agents through an intracellular mechanism that does not involve the activation of upstream components of the CWI pathway. Additional observations suggest that protein kinase C (Pkc1), the top kinase in the CWI signaling cascade, also has a role in the response to genotoxic stress that is independent of its recognized function in the activation of Mpk1. Pkc1 undergoes hyper-phosphorylation specifically in response to genotoxic stress; we have found that this requires the DNA damage checkpoint kinases Mec1 (Mitosis Entry Checkpoint) and Tel1 (TELomere maintenance), but not their effector kinases. We demonstrate that the casein kinase 1 (CK1) ortholog, Hrr25 (HO and Radiation Repair), previously implicated in the DNA damage transcriptional response, associates with Pkc1 under conditions of genotoxic stress. We also found that the induced association of Hrr25 with Pkc1 requires Mec1 and Tel1, and that Hrr25 catalytic activity is required for Pkc1-hyperphosphorylation, thereby delineating a pathway from the checkpoint kinases to Pkc1. We used SILAC mass spectrometry to identify three residues within Pkc1 the phosphorylation of which was stimulated by genotoxic stress. We mutated these residues as well as a collection of 13 phosphorylation sites within the regulatory domain of Pkc1 that fit the consensus for CK1 sites. Mutation of the 13 Pkc1 phosphorylation sites blocked hyper-phosphorylation and diminished RNR3 (RiboNucleotide Reductase) basal expression and induction by genotoxic stress, suggesting that Pkc1 plays a role in the DNA damage transcriptional response.

scholarly journals Identification of cis Elements Directing Termination of Yeast Nonpolyadenylated snoRNA Transcripts

2004 ◽  
Vol 24 (14) ◽  
pp. 6241-6252 ◽  
Author(s):  
Kristina L. Carroll ◽  
Dennis A. Pradhan ◽  
Josh A. Granek ◽  
Neil D. Clarke ◽  
Jeffry L. Corden
Keyword(s):  
Rna Polymerase Ii ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Large Degree ◽  
Sequence Motifs ◽  
Mobility Shift ◽  
Nascent Transcript ◽  
Pol Ii ◽  
Gel Mobility Shift

ABSTRACT RNA polymerase II (Pol II) termination is triggered by sequences present in the nascent transcript. Termination of pre-mRNA transcription is coupled to recognition of cis-acting sequences that direct cleavage and polyadenylation of the pre-mRNA. Termination of nonpolyadenylated [non-poly(A)] Pol II transcripts in Saccharomyces cerevisiae requires the RNA-binding proteins Nrd1 and Nab3. We have used a mutational strategy to characterize non-poly(A) termination elements downstream of the SNR13 and SNR47 snoRNA genes. This approach detected two common RNA sequence motifs, GUA[AG] and UCUU. The first motif corresponds to the known Nrd1-binding site, which we have verified here by gel mobility shift assays. We also show that Nab3 protein binds specifically to RNA containing the UCUU motif. Taken together, our data suggest that Nrd1 and Nab3 binding sites play a significant role in defining non-poly(A) terminators. As is the case with poly(A) terminators, there is no strong consensus for non-poly(A) terminators, and the arrangement of Nrd1p and Nab3p binding sites varies considerably. In addition, the organization of these sequences is not strongly conserved among even closely related yeasts. This indicates a large degree of genetic variability. Despite this variability, we were able to use a computational model to show that the binding sites for Nrd1 and Nab3 can identify genes for which transcription termination is mediated by these proteins.

scholarly journals Hypersensitivity to DNA damage leads to increased apoptosis during early mouse development

2000 ◽  
Vol 14 (16) ◽  
pp. 2072-2084
Author(s):  
Babette S. Heyer ◽  
Alasdair MacAuley ◽  
Ole Behrendtsen ◽  
Zena Werb
Keyword(s):  
Dna Damage ◽  
Cell Fate ◽  
Genotoxic Stress ◽  
Embryonic Cells ◽  
Mouse Development ◽  
Potential Cost ◽  
Proliferation And Differentiation ◽  
A Cell ◽  
Early Mouse ◽  
Surveillance Mechanism

Gastrulation in mice is associated with the start of extreme proliferation and differentiation. The potential cost to the embryo of a very rapid proliferation rate is a high production of damaged cells. We demonstrate a novel surveillance mechanism for the elimination of cells damaged by ionizing radiation during mouse gastrulation. During this restricted developmental window, the embryo becomes hypersensitive to DNA damage induced by low dose irradiation (<0.5 Gy) and undergoes apoptosis without cell cycle arrest. Intriguingly, embryonic cells, including germ cell progenitors, but not extraembryonic cells, become hypersensitive to genotoxic stress and undergo Atm- and p53-dependent apoptosis. Thus, hypersensitivity to apoptosis in the early mouse embryo is a cell fate-dependent mechanism to ensure genomic integrity during a period of extreme proliferation and differentiation.

The Transcriptional Intermediary Factor TIF1γ Controls Erythroid Cell Fate by Specifically Regulating Transcriptional Elongation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 254-254
Author(s):  
Xiaoying Bai ◽  
Joseph Lee ◽  
Jocelyn LeBlanc ◽  
Anna Sessa ◽  
Zhongan Yang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Cell Fate ◽  
Erythroid Cell ◽  
Transcriptional Elongation ◽  
Pol Ii ◽  
Physical Interactions ◽  
Paf1 Complex

Abstract Abstract 254 Vertebrate erythropoiesis is regulated by cell-specific transcription factors, RNA polymerase-associated basal machinery and chromatin remodeling factors. One critical chromatin factor is the transcriptional intermediary factor TIF1γ. Loss of TIF1γfunction in zebrafish mutant moonshine causes a profound anemia during embryogenesis, associated with a progressive decrease in expression of most erythroid mRNAs such as GATA1 and globin. TIF1γdeficiency has also been linked to TGF-βsignaling, although the in vivo mechanism for the anemia remains unclear. In an effort to find genes that interact with TIF1γ, we undertook a genetic suppressor screen in which we sought mutations in another gene that would restore blood to normal levels in the background of moonshine deficiency. Few suppressor screens have been done in vertebrate genetic models, and the haploid genetics of zebrafish was a great advantage for this screen. After screening 800 families of fish, two suppressor mutants, “eclipse” and “sunrise”, were found that could greatly rescue the erythroid defects in moonshine. The deficient gene in sunrise has been mapped to the locus of cdc73 (also known as parafibromin/HRPT2), a subunit of the PAF1 complex known to regulate RNA polymerase II (Pol II) elongation and chromatin modification. Furthermore, we have found that knocking down other subunits in the PAF1 complex also rescued the blood defect in moonshine, suggesting that PAF1 as a complex antagonizes TIF1γfunction during erythropoiesis. In yeast, PAF1 has been shown to physically or genetically interact with other elongation factors including DSIF, FACT and p-TEFb. We have found that knocking down DSIF, which is known to induce Pol II pausing during early elongation, also rescues moonshine. FACT and p-TEFb are both known to counteract DSIF to release Pol II from pausing, and knocking down FACT and p-TEFb caused the zebrafish to develop anemia. This strongly suggests that the erythroid defects in TIF1γdeficiency is caused by attenuated Pol II elongation. In an effort to understand the cell-specific phenotype of TIF1γdeficiency, we introduced a FLAG tagged TIF1γinto K562 erythroleukemia cells to pull down interacting proteins. Physical interactions were found among TIF1γ, FACT, p-TEFb and surprisingly the SCL hematopoietic transcription complex. The interaction with the SCL complex provides a cell-specific control over transcriptional elongation. The physical interactions, taken together with the genetic data, suggest a novel mechanism regulating erythropoiesis. TIF1γphysically and functionally links blood-specific transcription factors like SCL to Pol II-associated elongation machinery to regulate blood cell fate. In light of the recent discoveries of widespread Pol II stalling in the promoter proximal region in metazoan genomes, we speculate that similar mechanisms will regulate cell fates in other blood lineages as well as non-blood tissues. Disclosures: Zon: FATE Inc: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Stemgent: Consultancy.

scholarly journals PPM1G Binds 7SK RNA and Hexim1 To Block P-TEFb Assembly into the 7SK snRNP and Sustain Transcription Elongation

2015 ◽  
Vol 35 (22) ◽  
pp. 3810-3828 ◽  
Author(s):  
Swapna Aravind Gudipaty ◽  
Ryan P. McNamara ◽  
Emily L. Morton ◽  
Iván D'Orso
Keyword(s):  
Rna Polymerase Ii ◽  
Noncoding Rna ◽  
Kinase Inhibitor ◽  
Transcription Elongation ◽  
Nuclear Factor Κb ◽  
Binding Activity ◽  
New Paradigm ◽  
Pol Ii ◽  
Small Nuclear Ribonucleoprotein ◽  
Rna Interaction

Transcription elongation programs are vital for the precise regulation of several biological processes. One key regulator of such programs is the P-TEFb kinase, which phosphorylates RNA polymerase II (Pol II) once released from the inhibitory 7SK small nuclear ribonucleoprotein (snRNP) complex. Although mechanisms of P-TEFb release from the snRNP are becoming clearer, how P-TEFb remains in the 7SK-unbound state to sustain transcription elongation programs remains unknown. Here we report that the PPM1G phosphatase (inducibly recruited by nuclear factor κB [NF-κB] to target promoters) directly binds 7SK RNA and the kinase inhibitor Hexim1 once P-TEFb has been released from the 7SK snRNP. This dual binding activity of PPM1G blocks P-TEFb reassembly onto the snRNP to sustain NF-κB-mediated Pol II transcription in response to DNA damage. Notably, the PPM1G-7SK RNA interaction is direct, kinetically follows the recruitment of PPM1G to promoters to activate NF-κB transcription, and is reversible, since the complex disassembles before resolution of the program. Strikingly, we found that the ataxia telangiectasia mutated (ATM) kinase regulates the interaction between PPM1G and the 7SK snRNP through site-specific PPM1G phosphorylation. The precise and temporally regulated interaction of a cellular enzyme and a noncoding RNA provides a new paradigm for simultaneously controlling the activation and maintenance of inducible transcription elongation programs.

scholarly journals cis- and trans-Acting Determinants of Transcription Termination by Yeast RNA Polymerase II

2006 ◽  
Vol 26 (7) ◽  
pp. 2688-2696 ◽  
Author(s):  
Eric J. Steinmetz ◽  
Sarah B. H. Ng ◽  
Joseph P. Cloute ◽  
David A. Brow
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Binding ◽  
Nascent Transcript ◽  
Protein Coding ◽  
Pol Ii ◽  
Eukaryotic Genes ◽  
Discrete Surface ◽  
Cleavage And Polyadenylation ◽  
Selection For

ABSTRACT Most eukaryotic genes are transcribed by RNA polymerase II (Pol II), including those that produce mRNAs and many noncoding functional RNAs. Proper expression of these genes requires efficient termination by Pol II to avoid transcriptional interference and synthesis of extended, nonfunctional RNAs. We previously described a pathway for yeast Pol II termination that involves recognition of an element in the nascent transcript by the essential RNA-binding protein Nrd1. The Nrd1-dependent pathway appears to be used primarily for nonpolyadenylated transcripts, such as the small nuclear and small nucleolar RNAs (snoRNAs). mRNAs are thought to use a distinct pathway that is coupled to cleavage and polyadenylation of the transcript. Here we show that the terminator elements for two yeast snoRNA genes also direct polyadenylated 3′-end formation in the context of an mRNA 3′ untranslated region. A selection for cis-acting terminator readthrough mutations identified conserved features of these elements, some of which are similar to cleavage and polyadenylation signals. A selection for trans-acting mutations that induce readthrough of both a snoRNA and an mRNA terminator yielded mutations in the Rpb3 and Rpb11 subunits of Pol II that define a remarkably discrete surface on the trailing end of the enzyme. Our results suggest that, at least in budding yeast, protein-coding and noncoding Pol II-transcribed genes use similar mechanisms to direct termination and that the termination signal is transduced through the Rpb3/Rpb11 heterodimer.

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