scholarly journals A CSB-PAF1C axis restores processive transcription elongation after DNA damage repair

2020 ◽  
Author(s):  
Diana van den Heuvel ◽  
Cornelia G. Spruijt ◽  
Román González-Prieto ◽  
Angela Kragten ◽  
Michelle T. Paulsen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Rna Polymerase Ii ◽  
Molecular Basis ◽  
Rna Synthesis ◽  
Transcription Elongation ◽  
Genotoxic Stress ◽  
Dna Lesions ◽  
Damage Repair ◽  
Processivity Factor ◽  
Dependent Pathway

AbstractThe coordinated transcription of genes involves the regulated release of RNA polymerase II (RNAPII) from promoter-proximal sites into active elongation. DNA lesions in transcribed strands block elongation and induce a strong transcriptional arrest. The transcription-coupled repair (TCR) pathway efficiently removes transcription-blocking DNA lesions, but this is not sufficient to resume transcription. Through proteomics screens, we find that the TCR-specific CSB protein loads the evolutionary conserved PAF1 complex (PAF1C) onto RNAPII in promoter-proximal regions in response to DNA damage. PAF1C is dispensable for TCR-mediated repair, but is essential for recovery of RNA synthesis after UV irradiation, suggesting an uncoupling between DNA repair and transcription recovery. Moreover, we find that PAF1C promotes RNAPII pause release in promoter-proximal regions and subsequently acts as a processivity factor that stimulates transcription elongation throughout genes. Our findings expose the molecular basis for a non-canonical PAF1C-dependent pathway that restores transcription throughout the human genome after genotoxic stress.

scholarly journals A CSB-PAF1C axis restores processive transcription elongation after DNA damage repair

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Diana van den Heuvel ◽  
Cornelia G. Spruijt ◽  
Román González-Prieto ◽  
Angela Kragten ◽  
Michelle T. Paulsen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Rna Polymerase Ii ◽  
Transcription Elongation ◽  
Genotoxic Stress ◽  
Dna Lesions ◽  
Damage Repair ◽  
Genome Wide ◽  
A Genome ◽  
Processivity Factor ◽  
Dependent Pathway

AbstractBulky DNA lesions in transcribed strands block RNA polymerase II (RNAPII) elongation and induce a genome-wide transcriptional arrest. The transcription-coupled repair (TCR) pathway efficiently removes transcription-blocking DNA lesions, but how transcription is restored in the genome following DNA repair remains unresolved. Here, we find that the TCR-specific CSB protein loads the PAF1 complex (PAF1C) onto RNAPII in promoter-proximal regions in response to DNA damage. Although dispensable for TCR-mediated repair, PAF1C is essential for transcription recovery after UV irradiation. We find that PAF1C promotes RNAPII pause release in promoter-proximal regions and subsequently acts as a processivity factor that stimulates transcription elongation throughout genes. Our findings expose the molecular basis for a non-canonical PAF1C-dependent pathway that restores transcription throughout the human genome after genotoxic stress.

scholarly journals DNA damage stabilizes interaction of CSB with the transcription elongation machinery

2004 ◽  
Vol 166 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Vincent van den Boom ◽  
Elisabetta Citterio ◽  
Deborah Hoogstraten ◽  
Angelika Zotter ◽  
Jean-Marc Egly ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dna Damage ◽  
Dna Repair ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
High Molecular Weight ◽  
Transcription Elongation ◽  
Cockayne Syndrome ◽  
Dna Lesions ◽  
High Molecular Weight Complex

The Cockayne syndrome B (CSB) protein is essential for transcription-coupled DNA repair (TCR), which is dependent on RNA polymerase II elongation. TCR is required to quickly remove the cytotoxic transcription-blocking DNA lesions. Functional GFP-tagged CSB, expressed at physiological levels, was homogeneously dispersed throughout the nucleoplasm in addition to bright nuclear foci and nucleolar accumulation. Photobleaching studies showed that GFP-CSB, as part of a high molecular weight complex, transiently interacts with the transcription machinery. Upon (DNA damage-induced) transcription arrest CSB binding these interactions are prolonged, most likely reflecting actual engagement of CSB in TCR. These findings are consistent with a model in which CSB monitors progression of transcription by regularly probing elongation complexes and becomes more tightly associated to these complexes when TCR is active.

scholarly journals Cockayne syndrome B protein acts as an ATP-dependent processivity factor that helps RNA polymerase II overcome nucleosome barriers

2020 ◽  
Vol 117 (41) ◽  
pp. 25486-25493 ◽  
Author(s):  
Jun Xu ◽  
Wei Wang ◽  
Liang Xu ◽  
Jia-Yu Chen ◽  
Jenny Chong ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Neurological Diseases ◽  
Transcription Elongation ◽  
Cockayne Syndrome ◽  
Stable Complex ◽  
Loss Of Function ◽  
Pol Ii ◽  
Chromatin Remodelers ◽  
Processivity Factor

While loss-of-function mutations in Cockayne syndrome group B protein (CSB) cause neurological diseases, this unique member of the SWI2/SNF2 family of chromatin remodelers has been broadly implicated in transcription elongation and transcription-coupled DNA damage repair, yet its mechanism remains largely elusive. Here, we use a reconstituted in vitro transcription system with purified polymerase II (Pol II) and Rad26, a yeast ortholog of CSB, to study the role of CSB in transcription elongation through nucleosome barriers. We show that CSB forms a stable complex with Pol II and acts as an ATP-dependent processivity factor that helps Pol II across a nucleosome barrier. This noncanonical mechanism is distinct from the canonical modes of chromatin remodelers that directly engage and remodel nucleosomes or transcription elongation factors that facilitate Pol II nucleosome bypass without hydrolyzing ATP. We propose a model where CSB facilitates gene expression by helping Pol II bypass chromatin obstacles while maintaining their structures.

scholarly journals Targeting DNA Replication Stress and DNA Double-Strand Break Repair for Optimizing SCLC Treatment

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1289 ◽  
Author(s):  
Xing Bian ◽  
Wenchu Lin
Keyword(s):  
Lung Cancer ◽  
Dna Damage ◽  
Dna Replication ◽  
Dna Damage Repair ◽  
Predictive Biomarkers ◽  
Replication Stress ◽  
Genotoxic Stress ◽  
Repair System ◽  
Damage Repair ◽  
Repair Pathways

Small cell lung cancer (SCLC), accounting for about 15% of all cases of lung cancer worldwide, is the most lethal form of lung cancer. Despite an initially high response rate of SCLC to standard treatment, almost all patients are invariably relapsed within one year. Effective therapeutic strategies are urgently needed to improve clinical outcomes. Replication stress is a hallmark of SCLC due to several intrinsic factors. As a consequence, constitutive activation of the replication stress response (RSR) pathway and DNA damage repair system is involved in counteracting this genotoxic stress. Therefore, therapeutic targeting of such RSR and DNA damage repair pathways will be likely to kill SCLC cells preferentially and may be exploited in improving chemotherapeutic efficiency through interfering with DNA replication to exert their functions. Here, we summarize potentially valuable targets involved in the RSR and DNA damage repair pathways, rationales for targeting them in SCLC treatment and ongoing clinical trials, as well as possible predictive biomarkers for patient selection in the management of SCLC.

scholarly journals Mutant huntingtin impairs PNKP and ATXN3, disrupting DNA repair and transcription

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Rui Gao ◽  
Anirban Chakraborty ◽  
Charlene Geater ◽  
Subrata Pradhan ◽  
Kara L Gordon ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Rna Polymerase Ii ◽  
Dna Damage Response ◽  
Functional Decline ◽  
Transcriptional Elongation ◽  
Damage Repair ◽  
Damage Response ◽  
Cyclic Amp Response Element ◽  
Atm Signaling

How huntingtin (HTT) triggers neurotoxicity in Huntington’s disease (HD) remains unclear. We report that HTT forms a transcription-coupled DNA repair (TCR) complex with RNA polymerase II subunit A (POLR2A), ataxin-3, the DNA repair enzyme polynucleotide-kinase-3'-phosphatase (PNKP), and cyclic AMP-response element-binding (CREB) protein (CBP). This complex senses and facilitates DNA damage repair during transcriptional elongation, but its functional integrity is impaired by mutant HTT. Abrogated PNKP activity results in persistent DNA break accumulation, preferentially in actively transcribed genes, and aberrant activation of DNA damage-response ataxia telangiectasia-mutated (ATM) signaling in HD transgenic mouse and cell models. A concomitant decrease in Ataxin-3 activity facilitates CBP ubiquitination and degradation, adversely impacting transcription and DNA repair. Increasing PNKP activity in mutant cells improves genome integrity and cell survival. These findings suggest a potential molecular mechanism of how mutant HTT activates DNA damage-response pro-degenerative pathways and impairs transcription, triggering neurotoxicity and functional decline in HD.

scholarly journals MORC2 regulates DNA damage response through a PARP1-dependent pathway

2019 ◽  
Vol 47 (16) ◽  
pp. 8502-8520 ◽  
Author(s):  
Lin Zhang ◽  
Da-Qiang Li
Keyword(s):  
Dna Damage ◽  
Zinc Finger ◽  
Chromatin Remodeling ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Genotoxic Stress ◽  
Underlying Mechanism ◽  
Dna Lesions ◽  
Damage Response

Abstract Microrchidia family CW-type zinc finger 2 (MORC2) is a newly identified chromatin remodeling enzyme with an emerging role in DNA damage response (DDR), but the underlying mechanism remains largely unknown. Here, we show that poly(ADP-ribose) polymerase 1 (PARP1), a key chromatin-associated enzyme responsible for the synthesis of poly(ADP-ribose) (PAR) polymers in mammalian cells, interacts with and PARylates MORC2 at two residues within its conserved CW-type zinc finger domain. Following DNA damage, PARP1 recruits MORC2 to DNA damage sites and catalyzes MORC2 PARylation, which stimulates its ATPase and chromatin remodeling activities. Mutation of PARylation residues in MORC2 results in reduced cell survival after DNA damage. MORC2, in turn, stabilizes PARP1 through enhancing acetyltransferase NAT10-mediated acetylation of PARP1 at lysine 949, which blocks its ubiquitination at the same residue and subsequent degradation by E3 ubiquitin ligase CHFR. Consequently, depletion of MORC2 or expression of an acetylation-defective PARP1 mutant impairs DNA damage-induced PAR production and PAR-dependent recruitment of DNA repair proteins to DNA lesions, leading to enhanced sensitivity to genotoxic stress. Collectively, these findings uncover a previously unrecognized mechanistic link between MORC2 and PARP1 in the regulation of cellular response to DNA damage.

scholarly journals DNA Damage-Inducing Anticancer Therapies: From Global to Precision Damage

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2098 ◽  
Author(s):  
Thom G. A. Reuvers ◽  
Roland Kanaar ◽  
Julie Nonnekens
Keyword(s):  
Dna Damage ◽  
Cellular Response ◽  
Cellular Proliferation ◽  
Dna Damage Repair ◽  
Therapy Response ◽  
Dna Lesions ◽  
Response To Therapy ◽  
Novel Therapy ◽  
Damage Repair ◽  
And Function

DNA damage-inducing therapies are of tremendous value for cancer treatment and function by the direct or indirect formation of DNA lesions and subsequent inhibition of cellular proliferation. Of central importance in the cellular response to therapy-induced DNA damage is the DNA damage response (DDR), a protein network guiding both DNA damage repair and the induction of cancer-eradicating mechanisms such as apoptosis. A detailed understanding of DNA damage induction and the DDR has greatly improved our knowledge of the classical DNA damage-inducing therapies, radiotherapy and cytotoxic chemotherapy, and has paved the way for rational improvement of these treatments. Moreover, compounds targeting specific DDR proteins, selectively impairing DNA damage repair in cancer cells, form a promising novel therapy class that is now entering the clinic. In this review, we give an overview of the current state and ongoing developments, and discuss potential avenues for improvement for DNA damage-inducing therapies, with a central focus on the role of the DDR in therapy response, toxicity and resistance. Furthermore, we describe the relevance of using combination regimens containing DNA damage-inducing therapies and how they can be utilized to potentiate other anticancer strategies such as immunotherapy.

Dealing with transcription-blocking DNA damage: repair mechanisms, RNA polymerase II processing and human disorders

DNA Repair ◽  
2021 ◽  
pp. 103192
Author(s):  
Nan Jia ◽  
Chaowan Guo ◽  
Yuka Nakazawa ◽  
Diana van den Heuvel ◽  
Martijn S. Luijsterburg ◽  
...  
Keyword(s):  
Dna Damage ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Dna Damage Repair ◽  
Damage Repair ◽  
Repair Mechanisms ◽  
Human Disorders

scholarly journals Mitotic repression of RNA polymerase II transcription is accompanied by release of transcription elongation complexes.

1997 ◽  
Vol 17 (10) ◽  
pp. 5791-5802 ◽  
Author(s):  
G G Parsons ◽  
C A Spencer
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Synthesis ◽  
Transcription Elongation ◽  
Control Cell ◽  
Specific Gene ◽  
Mitotic Chromosomes ◽  
Transcription Repression ◽  
Rna Polymerase Ii Transcription

Nuclear RNA synthesis is repressed during the mitotic phase of each cell cycle. Although total RNA synthesis remains low throughout mitosis, the degree of RNA polymerase II transcription repression on specific genes has not been examined. In addition, it is not known whether mitotic repression of RNA polymerase II transcription is due to polymerase pausing or ejection of transcription elongation complexes from mitotic chromosomes. In this study, we show that RNA polymerase II transcription is repressed in mammalian cells on a number of specific gene regions during mitosis. We also show that the majority of RNA polymerase II transcription elongation complexes are physically excluded from mitotic chromosomes between late prophase and late telophase. Despite generalized transcription repression and stripping of RNA polymerase II complexes from DNA, arrested RNA polymerase II ternary complexes appear to remain on some gene regions during mitosis. The cyclic repression of transcription and ejection of RNA polymerase II transcription elongation complexes may help regulate the transcriptional events that control cell cycle progression and differentiation.

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