scholarly journals HPF1-dependent histone ADP-ribosylation triggers chromatin relaxation to promote the recruitment of repair factors at sites of DNA damage

2021 ◽  
Author(s):  
Rebecca Smith ◽  
Siham Zentout ◽  
Catherine Chapuis ◽  
Gyula Timinszky ◽  
Sebastien Huet
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Dna Lesions ◽  
End Joining ◽  
Adp Ribosylation ◽  
Damage Response ◽  
Non Homologous End Joining ◽  
Chromatin Relaxation ◽  
The Impact

PARP1 activity is regulated by its cofactor HPF1. The binding of HPF1 on PARP1 controls the grafting of ADP-ribose moieties on serine residues of proteins nearby the DNA lesions, mainly PARP1 and histones. However, the impact of HPF1 on DNA repair regulated by PARP1 remains unclear. Here, we show that HPF1 controls both the number and the length of the ADP-ribose chains generated by PARP1 at DNA lesions. We demonstrate that HPF1-dependent histone ADP-ribosylation, rather than auto-modification of PARP1, triggers the rapid unfolding of the chromatin structure at the DNA damage sites and promotes the recruitment of the repair factors CHD4 and CHD7. Together with the observation that HPF1 contributes to efficient repair both by homologous recombination and non-homologous end joining, our findings highlight the key roles played by this PARP1 cofactor at early stages of the DNA damage response.

scholarly journals The Intermediate Filament Synemin Regulates Non-Homologous End Joining in an ATM-Dependent Manner

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1717 ◽  
Author(s):  
Sara Sofia Deville ◽  
Anne Vehlow ◽  
Sarah Förster ◽  
Ellen Dickreuter ◽  
Kerstin Borgmann ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Intermediate Filament ◽  
Intermediate Filament Protein ◽  
Dependent Manner ◽  
End Joining ◽  
Damage Response ◽  
Non Homologous End Joining ◽  
Filament Protein

The treatment resistance of cancer cells is a multifaceted process in which DNA repair emerged as a potential therapeutic target. DNA repair is predominantly conducted by nuclear events; yet, how extra-nuclear cues impact the DNA damage response is largely unknown. Here, using a high-throughput RNAi-based screen in three-dimensionally-grown cell cultures of head and neck squamous cell carcinoma (HNSCC), we identified novel focal adhesion proteins controlling DNA repair, including the intermediate filament protein, synemin. We demonstrate that synemin critically regulates the DNA damage response by non-homologous end joining repair. Mechanistically, synemin forms a protein complex with DNA-PKcs through its C-terminal tail domain for determining DNA repair processes upstream of this enzyme in an ATM-dependent manner. Our study discovers a critical function of the intermediate filament protein, synemin in the DNA damage response, fundamentally supporting the concept of cytoarchitectural elements as co-regulators of nuclear events.

scholarly journals Functional Roles of Homologous Recombination and Non-Homologous End Joining in DNA Damage Response and Microevolution in Cryptococcus neoformans

2021 ◽  
Vol 7 (7) ◽  
pp. 566
Author(s):  
Kwang-Woo Jung ◽  
Jong-Hyun Jung ◽  
Ha-Young Park
Keyword(s):  
Dna Damage ◽  
Homologous Recombination ◽  
Cryptococcus Neoformans ◽  
Dna Damage Response ◽  
Genotoxic Stress ◽  
Dna Lesions ◽  
Dependent Manner ◽  
End Joining ◽  
Damage Response ◽  
Non Homologous End Joining

DNA double-strand breaks (DSBs) are the most deleterious type of DNA lesions because they cause loss of genetic information if not properly repaired. In eukaryotes, homologous recombination (HR) and non-homologous end joining (NHEJ) are required for DSB repair. However, the relationship of HR and NHEJ in DNA damage stress is unknown in the radiation-resistant fungus Cryptococcus neoformans. In this study, we found that the expression levels of HR- and NHEJ-related genes were highly induced in a Rad53–Bdr1 pathway-dependent manner under genotoxic stress. Deletion of RAD51, which is one of the main components in the HR, resulted in growth under diverse types of DNA damage stress, whereas perturbations of KU70 and KU80, which belong to the NHEJ system, did not affect the genotoxic stresses except when bleomycin was used for treatment. Furthermore, deletion of both RAD51 and KU70/80 renders cells susceptible to oxidative stress. Notably, we found that deletion of RAD51 induced a hypermutator phenotype in the fluctuation assay. In contrast to the fluctuation assay, perturbation of KU70 or KU80 induced rapid microevolution similar to that induced by the deletion of RAD51. Collectively, Rad51-mediated HR and Ku70/Ku80-mediated NHEJ regulate the DNA damage response and maintain genome stability.

scholarly journals DNArepairK: An Interactive Database for Exploring the Impact of Anticancer Drugs onto the Dynamics of DNA Repair Proteins

Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1238
Author(s):  
Yordan Babukov ◽  
Radoslav Aleksandrov ◽  
Aneliya Ivanova ◽  
Aleksandar Atemin ◽  
Stoyno Stoynov
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Anticancer Drugs ◽  
Dna Damage Response ◽  
Graphical Representation ◽  
Repair Process ◽  
Dna Lesions ◽  
Damage Response ◽  
Dna Repair Proteins ◽  
The Impact

Cells are constantly exposed to numerous mutagens that produce diverse types of DNA lesions. Eukaryotic cells have evolved an impressive array of DNA repair mechanisms that are able to detect and repair these lesions, thus preventing genomic instability. The DNA repair process is subjected to precise spatiotemporal coordination, and repair proteins are recruited to lesions in an orderly fashion, depending on their function. Here, we present DNArepairK, a unique open-access database that contains the kinetics of recruitment and removal of 70 fluorescently tagged DNA repair proteins to complex DNA damage sites in living HeLa Kyoto cells. An interactive graphical representation of the data complemented with live cell imaging movies facilitates straightforward comparisons between the dynamics of proteins contributing to different DNA repair pathways. Notably, most of the proteins included in DNArepairK are represented by their kinetics in both nontreated and PARP1/2 inhibitor-treated (talazoparib) cells, thereby providing an unprecedented overview of the effects of anticancer drugs on the regular dynamics of the DNA damage response. We believe that the exclusive dataset available in DNArepairK will be of value to scientists exploring the DNA damage response but, also, to inform and guide the development and evaluation of novel DNA repair-targeting anticancer drugs.

scholarly journals DROSHA associates to DNA damage sites and is required for DNA repair

2018 ◽  
Author(s):  
Matteo Cabrini ◽  
Marco Roncador ◽  
Alessandro Galbiati ◽  
Lina Cipolla ◽  
Fabio Iannelli ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Dna Lesions ◽  
Cellular System ◽  
Proximity Ligation Assay ◽  
Dna Double Strand Breaks ◽  
Proximity Ligation ◽  
Damage Response ◽  
Non Homologous End Joining

AbstractThe DNA damage response (DDR) is the signaling cascade through which a cell recognizes DNA lesions, and promotes their resolution via the repair pathways of Non-Homologous End Joining (NHEJ), or Homologous Recombination (HR). We recently demonstrated that DROSHA boosts DDR signaling by processing damage-induced long non-coding RNAs into smaller DNA damage response RNAs (DDRNAs). However, the location at which DROSHA exerts its DDR functions, relative to sites of DNA damage, remains unknown.To investigate DROSHA’s localization during DDR activation, we used the DiVA cellular system, which allows the controlled induction of several DNA double strand breaks (DSBs) in the human genome. Indeed, by genome wide chromatin immunoprecipitation followed by next generation sequencing, we demonstrate that DROSHA associates with DSBs. In support of this, DSB-recruitment of DROSHA is detectable at the single-cell level by Proximity Ligation Assay between DROSHA and known DDR markers, and by DNA damage in situ ligation followed by Proximity Ligation Assay (DI-PLA), which demonstrates proximity of DROSHA to DNA ends. DROSHA recruitment occurs at both genic and inter-genic DSBs, suggesting that its recruitment is independent from ongoing transcription preceding damage generation. DROSHA’s recruitment to DNA lesions occurs throughout the cell cycle, and with a preference for NHEJ-prone DSBs. Consistently, inhibition of the HR pathway increases DROSHA recruitment, and DROSHA knock down strongly impairs NHEJ efficiency in a GFP-reporter cellular system for monitoring NHEJ DNA repair. Overall, these results demonstrate that DROSHA acts locally at sites of DNA damage to promote NHEJ DNA repair.

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

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.

scholarly journals Biomarkers of DNA Damage Response Enable Flow Cytometry-Based Diagnostic to Identify Inborn DNA Repair Defects in Primary Immunodeficiencies

2021 ◽  
Author(s):  
Kerstin Felgentreff ◽  
Ulrich Baumann ◽  
Christian Klemann ◽  
Catharina Schuetz ◽  
Dorothee Viemann ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Cancer Susceptibility ◽  
Bone Marrow Failure ◽  
Dna Lesions ◽  
Diagnostic Tools ◽  
Cellular Models ◽  
Damage Response

AbstractDNA damage is a constant event in every cell caused by exogenous factors such as ultraviolet and ionizing radiation (UVR/IR) and intercalating drugs, or endogenous metabolic and replicative stress. Proteins of the DNA damage response (DDR) network sense DNA lesions and induce cell cycle arrest, DNA repair, and apoptosis. Genetic defects of DDR or DNA repair proteins can be associated with immunodeficiency, bone marrow failure syndromes, and cancer susceptibility. Although various diagnostic tools are available to evaluate DNA damage, their quality to identify DNA repair deficiencies differs enormously and depends on affected pathways. In this study, we investigated the DDR biomarkers γH2AX (Ser139), p-ATM (Ser1981), and p-CHK2 (Thr68) using flow cytometry on peripheral blood cells obtained from patients with combined immunodeficiencies due to non-homologous end-joining (NHEJ) defects and ataxia telangiectasia (AT) in response to low-dose IR. Significantly reduced induction of all three markers was observed in AT patients compared to controls. However, delayed downregulation of γH2AX was found in patients with NHEJ defects. In contrast to previous reports of DDR in cellular models, these biomarkers were not sensitive enough to identify ARTEMIS deficiency with sufficient reliability. In summary, DDR biomarkers are suitable for diagnosing NHEJ defects and AT, which can be useful in neonates with abnormal TREC levels (T cell receptor excision circles) identified by newborn screening. We conclude that DDR biomarkers have benefits and some limitations depending on the underlying DNA repair deficiency.

scholarly journals Modified chromosome structure caused by phosphomimetic H2A modulates the DNA damage response by increasing chromatin mobility in yeast

2021 ◽  
Vol 134 (6) ◽  
Author(s):  
Fabiola García Fernández ◽  
Brenda Lemos ◽  
Yasmine Khalil ◽  
Renaud Batrin ◽  
James E. Haber ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Structural Changes ◽  
Sharp Decrease ◽  
Histone H2a ◽  
End Joining ◽  
Chromatin Dynamics ◽  
Damage Response ◽  
Chromatin Structural ◽  
Non Homologous End Joining

ABSTRACT In budding yeast and mammals, double-strand breaks (DSBs) trigger global chromatin mobility together with rapid phosphorylation of histone H2A over an extensive region of the chromatin. To assess the role of H2A phosphorylation in this response to DNA damage, we have constructed strains where H2A has been mutated to the phosphomimetic H2A-S129E. We show that mimicking H2A phosphorylation leads to an increase in global chromatin mobility in the absence of DNA damage. The intrinsic chromatin mobility of H2A-S129E is not due to downstream checkpoint activation, histone degradation or kinetochore anchoring. Rather, the increased intrachromosomal distances observed in the H2A-S129E mutant are consistent with chromatin structural changes. Strikingly, in this context the Rad9-dependent checkpoint becomes dispensable. Moreover, increased chromatin dynamics in the H2A-S129E mutant correlates with improved DSB repair by non-homologous end joining and a sharp decrease in interchromosomal translocation rate. We propose that changes in chromosomal conformation due to H2A phosphorylation are sufficient to modulate the DNA damage response and maintain genome integrity. This article has an associated First Person interview with the first author of the paper.

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