Nuclear WRAP53 promotes neuronal survival and functional recovery after stroke

Failure of neurons to efficiently repair DNA double-strand breaks (DSBs) contributes to cerebral damage after stroke. However, the molecular machinery that regulates DNA repair in this neurological disorder is unknown. Here, we found that DSBs in oxygen/glucose-deprived (OGD) neurons spatiotemporally correlated with the up-regulation of WRAP53 (WD40-encoding p53-antisense RNA), which translocated to the nucleus to activate the DSB repair response. Mechanistically, OGD triggered a burst in reactive oxygen species that induced both DSBs and translocation of WRAP53 to the nucleus to promote DNA repair, a pathway that was confirmed in an in vivo mouse model of stroke. Noticeably, nuclear translocation of WRAP53 occurred faster in OGD neurons expressing the Wrap53 human nonsynonymous single-nucleotide polymorphism (SNP) rs2287499 (c.202C>G). Patients carrying this SNP showed less infarct volume and better functional outcome after stroke. These results indicate that WRAP53 fosters DNA repair and neuronal survival to promote functional recovery after stroke.

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STEM-22. TARGETING REPLICATION STRESS RESPONSE FOR GLIOMA STEM CELL SPECIFIC CYTOTOXICITY

Neuro-Oncology ◽

10.1093/neuonc/noab196.096 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi25-vi26

Author(s):

Emily Clough ◽

Tracy Ballinger ◽

Colin Semple ◽

Karen Strathdee ◽

ross carruthers

Keyword(s):

Dna Repair ◽

Replication Stress ◽

Nuclear Bodies ◽

Parp Inhibition ◽

Dna Double Strand Breaks ◽

Origin Firing ◽

Strand Breaks ◽

Specific Cytotoxicity ◽

Dna Replication Stress

Abstract BACKGROUND Evidence suggests treatment resistant glioma stem cells (GSCs) drive glioblastoma (GBM) recurrence. Current treatments fail to eradicate GSC and novel GSC targeting therapies are a priority. GSC exhibit elevated DNA replication stress (RS) versus non GSC tumour cells driving constitutive DNA damage response (DDR) activation and efficient DNA repair. We previously demonstrated that targeting RS response with combined ATR and PARP inhibition (CAiPi) (VE821 and Olaparib) provides potent GSC specific cytotoxicity. In this study we investigated the underlying DDR phenotype which determines this vulnerability. RESULTS Paired GSC enriched (‘GSC’) and GSC depleted, differentiated (‘bulk’) populations were cultured from GBM specimens in neurobasal media with growth factors or serum containing media respectively. GSC exhibited reduced survival following exposure to CAiPi versus bulk. CAiPi significantly increased 53BP1 G1 phase nuclear bodies (53BP1NBs) in GSC, which are known to shield under-replicated DNA in actively transcribed genes. Mapping the genomic distribution of endogenously occurring replication dependent DNA double strand breaks via Breaks Ligation In Situ Sequencing (BLISS), revealed reduced intragenic DSB in long actively transcribed genes in GSC versus bulk at baseline, suggesting a reliance upon transcription coupled DSB repair in GSC. RNA seq demonstrated CAiPi-induced transcriptomic alterations in GSC including replication regulation and initiation. DNA fibre assay showed that CAiPi increased GSC new origin firing which correlated with PARP trapping. GSCs were rescued from CAiPi by roscovitine induced inhibition of excess origin firing. CAiPi is potently radiosensitizing by clonogenic assay and we demonstrated murine blood brain barrier penetration of CAiPi utilising VE822 and pamiparib in vivo. CONCLUSION Dysregulation of origin firing by CAiPi exposes a GSC specific vulnerability which results in DNA under-replication and abrogation of proficient DNA repair seen at long actively transcribed genes and has potential to be clinically translated as a GSC specific cytotoxic therapy.

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Increased BUB1B/BUBR1 expression contributes to aberrant DNA repair activity leading to resistance to DNA-damaging agents

Oncogene ◽

10.1038/s41388-021-02021-y ◽

2021 ◽

Author(s):

Kazumasa Komura ◽

Teruo Inamoto ◽

Takuya Tsujino ◽

Yusuke Matsui ◽

Tsuyoshi Konuma ◽

...

Keyword(s):

Dna Repair ◽

Nonhomologous End Joining ◽

Dependent Manner ◽

Dna Double Strand Breaks ◽

End Joining ◽

Strand Breaks ◽

Dna Damaging Agents ◽

Repair Activity ◽

A Cell

AbstractThere has been accumulating evidence for the clinical benefit of chemoradiation therapy (CRT), whereas mechanisms in CRT-recurrent clones derived from the primary tumor are still elusive. Herein, we identified an aberrant BUB1B/BUBR1 expression in CRT-recurrent clones in bladder cancer (BC) by comprehensive proteomic analysis. CRT-recurrent BC cells exhibited a cell-cycle-independent upregulation of BUB1B/BUBR1 expression rendering an enhanced DNA repair activity in response to DNA double-strand breaks (DSBs). With DNA repair analyses employing the CRISPR/cas9 system, we revealed that cells with aberrant BUB1B/BUBR1 expression dominantly exploit mutagenic nonhomologous end joining (NHEJ). We further found that phosphorylated ATM interacts with BUB1B/BUBR1 after ionizing radiation (IR) treatment, and the resistance to DSBs by increased BUB1B/BUBR1 depends on the functional ATM. In vivo, tumor growth of CRT-resistant T24R cells was abrogated by ATM inhibition using AZD0156. A dataset analysis identified FOXM1 as a putative BUB1B/BUBR1-targeting transcription factor causing its increased expression. These data collectively suggest a redundant role of BUB1B/BUBR1 underlying mutagenic NHEJ in an ATM-dependent manner, aside from the canonical activity of BUB1B/BUBR1 on the G2/M checkpoint, and offer novel clues to overcome CRT resistance.

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Involvement of Ku80 in microhomology-mediated end joining for DNA double-strand breaks in vivo

DNA Repair ◽

10.1016/j.dnarep.2006.12.002 ◽

2007 ◽

Vol 6 (5) ◽

pp. 639-648 ◽

Cited By ~ 19

Author(s):

Yukitaka Katsura ◽

Shigeru Sasaki ◽

Masanori Sato ◽

Kiyoshi Yamaoka ◽

Kazumi Suzukawa ◽

...

Keyword(s):

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

End Joining ◽

Strand Breaks

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Autophosphorylation of DNA-PKCS regulates its dynamics at DNA double-strand breaks

The Journal of Cell Biology ◽

10.1083/jcb.200608077 ◽

2007 ◽

Vol 177 (2) ◽

pp. 219-229 ◽

Cited By ~ 256

Author(s):

Naoya Uematsu ◽

Eric Weterings ◽

Ken-ichi Yano ◽

Keiko Morotomi-Yano ◽

Burkhard Jakob ◽

...

Keyword(s):

Kinase Activity ◽

Laser System ◽

Double Strand Breaks ◽

Dependent Manner ◽

Dna Double Strand Breaks ◽

End Joining ◽

Dsb Repair ◽

Strand Breaks ◽

Dna Ends

The DNA-dependent protein kinase catalytic subunit (DNA-PKCS) plays an important role during the repair of DNA double-strand breaks (DSBs). It is recruited to DNA ends in the early stages of the nonhomologous end-joining (NHEJ) process, which mediates DSB repair. To study DNA-PKCS recruitment in vivo, we used a laser system to introduce DSBs in a specified region of the cell nucleus. We show that DNA-PKCS accumulates at DSB sites in a Ku80-dependent manner, and that neither the kinase activity nor the phosphorylation status of DNA-PKCS influences its initial accumulation. However, impairment of both of these functions results in deficient DSB repair and the maintained presence of DNA-PKCS at unrepaired DSBs. The use of photobleaching techniques allowed us to determine that the kinase activity and phosphorylation status of DNA-PKCS influence the stability of its binding to DNA ends. We suggest a model in which DNA-PKCS phosphorylation/autophosphorylation facilitates NHEJ by destabilizing the interaction of DNA-PKCS with the DNA ends.

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End-resection at DNA double-strand breaks in the three domains of life

Biochemical Society Transactions ◽

10.1042/bst20120307 ◽

2013 ◽

Vol 41 (1) ◽

pp. 314-320 ◽

Cited By ~ 30

Author(s):

John K. Blackwood ◽

Neil J. Rzechorzek ◽

Sian M. Bray ◽

Joseph D. Maman ◽

Luca Pellegrini ◽

...

Keyword(s):

Dna Repair ◽

Homologous Recombination ◽

Strand Break ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Strand Breaks ◽

Homologous Chromosomes ◽

Domains Of Life ◽

Strand Invasion ◽

End Resection

During DNA repair by HR (homologous recombination), the ends of a DNA DSB (double-strand break) must be resected to generate single-stranded tails, which are required for strand invasion and exchange with homologous chromosomes. This 5′–3′ end-resection of the DNA duplex is an essential process, conserved across all three domains of life: the bacteria, eukaryota and archaea. In the present review, we examine the numerous and redundant helicase and nuclease systems that function as the enzymatic analogues for this crucial process in the three major phylogenetic divisions.

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Genetic Separation of Sae2 Nuclease Activity from Mre11 Nuclease Functions in Budding Yeast

Molecular and Cellular Biology ◽

10.1128/mcb.00156-17 ◽

2017 ◽

Vol 37 (24) ◽

Cited By ~ 8

Author(s):

Sucheta Arora ◽

Rajashree A. Deshpande ◽

Martin Budd ◽

Judy Campbell ◽

America Revere ◽

...

Keyword(s):

Nuclease Activity ◽

Double Strand Breaks ◽

Endonuclease Activity ◽

Dna Double Strand Breaks ◽

Dna Breaks ◽

Content Type ◽

Strand Breaks ◽

Dna Ends

ABSTRACT Sae2 promotes the repair of DNA double-strand breaks in Saccharomyces cerevisiae. The role of Sae2 is linked to the Mre11/Rad50/Xrs2 (MRX) complex, which is important for the processing of DNA ends into single-stranded substrates for homologous recombination. Sae2 has intrinsic endonuclease activity, but the role of this activity has not been assessed independently from its functions in promoting Mre11 nuclease activity. Here we identify and characterize separation-of-function mutants that lack intrinsic nuclease activity or the ability to promote Mre11 endonucleolytic activity. We find that the ability of Sae2 to promote MRX nuclease functions is important for DNA damage survival, particularly in the absence of Dna2 nuclease activity. In contrast, Sae2 nuclease activity is essential for DNA repair when the Mre11 nuclease is compromised. Resection of DNA breaks is impaired when either Sae2 activity is blocked, suggesting roles for both Mre11 and Sae2 nuclease activities in promoting the processing of DNA ends in vivo. Finally, both activities of Sae2 are important for sporulation, indicating that the processing of meiotic breaks requires both Mre11 and Sae2 nuclease activities.

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Emerging Technologies for Genome-Wide Profiling of DNA Breakage

Frontiers in Genetics ◽

10.3389/fgene.2020.610386 ◽

2021 ◽

Vol 11 ◽

Author(s):

Matthew J. Rybin ◽

Melina Ramic ◽

Natalie R. Ricciardi ◽

Philipp Kapranov ◽

Claes Wahlestedt ◽

...

Keyword(s):

Genome Instability ◽

Dna Double Strand Breaks ◽

Single Nucleotide ◽

Strand Breaks ◽

Single Strand Breaks ◽

Genome Wide ◽

A Genome ◽

Wide Scale ◽

Nucleotide Resolution ◽

Genomic Regions

Genome instability is associated with myriad human diseases and is a well-known feature of both cancer and neurodegenerative disease. Until recently, the ability to assess DNA damage—the principal driver of genome instability—was limited to relatively imprecise methods or restricted to studying predefined genomic regions. Recently, new techniques for detecting DNA double strand breaks (DSBs) and single strand breaks (SSBs) with next-generation sequencing on a genome-wide scale with single nucleotide resolution have emerged. With these new tools, efforts are underway to define the “breakome” in normal aging and disease. Here, we compare the relative strengths and weaknesses of these technologies and their potential application to studying neurodegenerative diseases.

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Recent advances in the nucleolar responses to DNA double-strand breaks

Nucleic Acids Research ◽

10.1093/nar/gkaa713 ◽

2020 ◽

Vol 48 (17) ◽

pp. 9449-9461

Author(s):

Lea Milling Korsholm ◽

Zita Gál ◽

Blanca Nieto ◽

Oliver Quevedo ◽

Stavroula Boukoura ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Dna Damage Response ◽

Ribosomal Dna ◽

Repetitive Sequences ◽

Dna Lesions ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Strand Breaks ◽

Damage Response

Abstract DNA damage poses a serious threat to human health and cells therefore continuously monitor and repair DNA lesions across the genome. Ribosomal DNA is a genomic domain that represents a particular challenge due to repetitive sequences, high transcriptional activity and its localization in the nucleolus, where the accessibility of DNA repair factors is limited. Recent discoveries have significantly extended our understanding of how cells respond to DNA double-strand breaks (DSBs) in the nucleolus, and new kinases and multiple down-stream targets have been identified. Restructuring of the nucleolus can occur as a consequence of DSBs and new data point to an active regulation of this process, challenging previous views. Furthermore, new insights into coordination of cell cycle phases and ribosomal DNA repair argue against existing concepts. In addition, the importance of nucleolar-DNA damage response (n-DDR) mechanisms for maintenance of genome stability and the potential of such factors as anti-cancer targets is becoming apparent. This review will provide a detailed discussion of recent findings and their implications for our understanding of the n-DDR. The n-DDR shares features with the DNA damage response (DDR) elsewhere in the genome but is also emerging as an independent response unique to ribosomal DNA and the nucleolus.

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In vivo analysis of FANCD2 recruitment at meiotic DNA breaks in Caenorhabditis elegans

Scientific Reports ◽

10.1038/s41598-019-57096-1 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Marcello Germoglio ◽

Anna Valenti ◽

Ines Gallo ◽

Chiara Forenza ◽

Pamela Santonicola ◽

...

Keyword(s):

Dna Repair ◽

Caenorhabditis Elegans ◽

Genome Stability ◽

Genetic Interaction ◽

Model Systems ◽

Dna Breaks ◽

Strand Breaks ◽

C Elegans ◽

In Vivo Analysis

AbstractFanconi Anemia is a rare genetic disease associated with DNA repair defects, congenital abnormalities and infertility. Most of FA pathway is evolutionary conserved, allowing dissection and mechanistic studies in simpler model systems such as Caenorhabditis elegans. In the present study, we employed C. elegans to better understand the role of FA group D2 (FANCD2) protein in vivo, a key player in promoting genome stability. We report that localization of FCD-2/FANCD2 is dynamic during meiotic prophase I and requires its heterodimeric partner FNCI-1/FANCI. Strikingly, we found that FCD-2 recruitment depends on SPO-11-induced double-strand breaks (DSBs) but not RAD-51-mediated strand invasion. Furthermore, exposure to DNA damage-inducing agents boosts FCD-2 recruitment on the chromatin. Finally, analysis of genetic interaction between FCD-2 and BRC-1 (the C. elegans orthologue of mammalian BRCA1) supports a role for these proteins in different DSB repair pathways. Collectively, we showed a direct involvement of FCD-2 at DSBs and speculate on its function in driving meiotic DNA repair.

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βarrestin-1 regulates DNA repair by acting as an E3-ubiquitin ligase adaptor for 53BP1

Cell Death and Differentiation ◽

10.1038/s41418-019-0406-6 ◽

2019 ◽

Vol 27 (4) ◽

pp. 1200-1213 ◽

Cited By ~ 1

Author(s):

Ainhoa Nieto ◽

Makoto R. Hara ◽

Victor Quereda ◽

Wayne Grant ◽

Vanessa Saunders ◽

...

Keyword(s):

Dna Damage ◽

Ionizing Radiation ◽

Ubiquitin Ligase ◽

E3 Ubiquitin Ligase ◽

Strand Break ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Molecular Scaffold ◽

Strand Breaks

Abstract Cellular DNA is constantly under threat from internal and external insults, consequently multiple pathways have evolved to maintain chromosomal fidelity. Our previous studies revealed that chronic stress, mediated by continuous stimulation of the β2-adrenergic-βarrestin-1 signaling axis suppresses activity of the tumor suppressor p53 and impairs genomic integrity. In this pathway, βarrestin-1 (βarr1) acts as a molecular scaffold to promote the binding and degradation of p53 by the E3-ubiquitin ligase, MDM2. We sought to determine whether βarr1 plays additional roles in the repair of DNA damage. Here we demonstrate that in mice βarr1 interacts with p53-binding protein 1 (53BP1) with major consequences for the repair of DNA double-strand breaks. 53BP1 is a principle component of the DNA damage response, and when recruited to the site of double-strand breaks in DNA, 53BP1 plays an important role coordinating repair of these toxic lesions. Here, we report that βarr1 directs 53BP1 degradation by acting as a scaffold for the E3-ubiquitin ligase Rad18. Consequently, knockdown of βarr1 stabilizes 53BP1 augmenting the number of 53BP1 DNA damage repair foci following exposure to ionizing radiation. Accordingly, βarr1 loss leads to a marked increase in irradiation resistance both in cells and in vivo. Thus, βarr1 is an important regulator of double strand break repair, and disruption of the βarr1/53BP1 interaction offers an attractive strategy to protect cells against high levels of exposure to ionizing radiation.

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