Dynamics of plant histone modifications in response to DNA damage

2012 ◽  
Vol 445 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Georgina E. Drury ◽  
Adam A. Dowle ◽  
David A. Ashford ◽  
Wanda M. Waterworth ◽  
Jerry Thomas ◽  
...  

DNA damage detection and repair take place in the context of chromatin, and histone proteins play important roles in these events. Post-translational modifications of histone proteins are involved in repair and DNA damage signalling processes in response to genotoxic stresses. In particular, acetylation of histones H3 and H4 plays an important role in the mammalian and yeast DNA damage response and survival under genotoxic stress. However, the role of post-translational modifications to histones during the plant DNA damage response is currently poorly understood. Several different acetylated H3 and H4 N-terminal peptides following X-ray treatment were identified using MS analysis of purified histones, revealing previously unseen patterns of histone acetylation in Arabidopsis. Immunoblot analysis revealed an increase in the relative abundance of the H3 acetylated N-terminus, and a global decrease in hyperacetylation of H4 in response to DNA damage induced by X-rays. Conversely, mutants in the key DNA damage signalling factor ATM (ATAXIA TELANGIECTASIA MUTATED) display increased histone acetylation upon irradiation, linking the DNA damage response with dynamic changes in histone modification in plants.

2019 ◽  
Vol 47 (16) ◽  
pp. 8502-8520 ◽  
Author(s):  
Lin Zhang ◽  
Da-Qiang Li

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.


2018 ◽  
Author(s):  
Laura A. Baker ◽  
Christoph Krisp ◽  
Daniel Roden ◽  
Holly Holliday ◽  
Sunny Z. Wu ◽  
...  

AbstractBasal-like breast cancer (BLBC) is a poorly characterised, heterogeneous disease. Patients are diagnosed with aggressive, high-grade tumours and often relapse with chemotherapy resistance. Detailed understanding of the molecular underpinnings of this disease is essential to the development of personalised therapeutic strategies. Inhibitor of Differentiation 4 (ID4) is a helix-loop-helix transcriptional regulator required for mammary gland development. ID4 is overexpressed in a subset of BLBC patients, associating with a stem-like poor prognosis phenotype, and is necessary for the growth of cell line models of BLBC, through unknown mechanisms. Here, we have defined a molecular mechanism of action for ID4 in BLBC and the related disease highgrade serous ovarian cancer (HGSOV), by combining RIME proteomic analysis and ChIP-Seq mapping of genomic binding sites. Remarkably, these studies have revealed novel interactions with DNA damage response proteins, in particular, mediator of DNA damage checkpoint protein 1 (MDC1). Through MDC1, ID4 interacts with other DNA repair proteins (γH2AX and BRCA1) at fragile chromatin sites. ID4 does not affect transcription at these sites, instead binding to chromatin following DNA damage and regulating DNA damage signalling. Clinical analysis demonstrates that ID4 is amplified and overexpressed at a higher frequency in BRCA1-mutant BLBC compared with sporadic BLBC, providing genetic evidence for an interaction between ID4 and DNA damage repair pathways. These data link the interactions of ID4 with MDC1 to DNA damage repair in the aetiology of BLBC and HGSOV.


2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10509-10509
Author(s):  
R. D. Kennedy ◽  
P. Stuckert ◽  
E. Archila ◽  
M. De LaVega ◽  
C. Chen ◽  
...  

10509 Loss of the fanconi anemia (FA) pathway function has been described in a number of sporadic tumor types including breast, ovarian, pancreatic, head and neck and hematological malignancies. Functionally, the FA pathway responds to stalled DNA replication following DNA damage. Given the importance of the FA pathway in the response to DNA damage, we hypothesized that cells deficient in this pathway may become hyper-dependent on alternative DNA damage response pathways in order to respond to endogenous genotoxic stress such as occurs during metabolism. Therefore, targeting these alternative pathways could offer therapeutic strategies in FA pathway deficient tumors. To identify new therapeutic targets we treated FA pathway competent and deficient cells with a DNA damage response siRNA library, that individually knocked out 230 genes. We identified a number of gene targets that were specifically toxic to FA pathway deficient cells, amongst which was the DNA damage response kinase Ataxia Telangiectasia Mutated (ATM). To test the requirement for ATM in FA pathway deficient cells, we interbred Fancg ± Atm± mice. Consistent with the siRNA screen result, Fancg-/- Atm-/- mice were non viable and Fancg± Atm-/- and Fancg-/- Atm ± progeny were less frequent that would have been expected. Several human cell lines with FA gene mutations were observed to have constitutive activation of ATM which was markedly reduced on correction with the appropriate wild-type FA gene. Interestingly, FA pathway deficient cells, including the FANCC mutant and FANCG mutant pancreatic cancer cell lines, were selectively sensitive to monotherapy with the ATM inhibitor KU55933, as measured by dose inhibition and colony count assays. FA pathway deficient cells also demonstrated an increased level of chromosomal breakage, cell cycle arrest and apoptosis following KU55933 treatment when compared to FA pathway corrected cells. We conclude that FA pathway deficient cells have an increased requirement for ATM activation in order to respond to sporadic DNA damage. This offers the possibility that monotherapy with ATM inhibitors could be a therapeutic strategy for tumors that are deficient for the FA pathway. No significant financial relationships to disclose.


2009 ◽  
Vol 130 (9) ◽  
pp. 637-647 ◽  
Author(s):  
Kirk Simon ◽  
Anju Mukundan ◽  
Samantha Dewundara ◽  
Holly Van Remmen ◽  
Alan A. Dombkowski ◽  
...  

2018 ◽  
Vol 315 (3) ◽  
pp. F469-F478 ◽  
Author(s):  
Liping Sun ◽  
Jing Liu ◽  
Yanggang Yuan ◽  
Xinzhou Zhang ◽  
Zheng Dong

As a potent chemotherapy drug, cisplatin is also notorious for its side-effects including nephrotoxicity in kidneys, presenting a pressing need to identify renoprotective agents. Cisplatin nephrotoxicity involves epigenetic regulations, including changes in histone acetylation. Bromodomain and extraterminal (BET) proteins are “readers” of the epigenetic code of histone acetylation. Here, we investigated the potential renoprotective effects of JQ1, a small molecule inhibitor of BET proteins. We show that JQ1 significantly ameliorated cisplatin-induced nephrotoxicity in mice as indicated by the measurements of kidney function, histopathology, and renal tubular apoptosis. JQ1 also partially prevented the body weight loss during cisplatin treatment in mice. Consistently, JQ1 inhibited cisplatin-induced apoptosis in renal proximal tubular cells. Mechanistically, JQ1 suppressed cisplatin-induced phosphorylation or activation of p53 and Chk2, key events in DNA damage response. JQ1 also attenuated cisplatin-induced MAP kinase (p38, ERK1/2, and JNK) activation. In addition, JQ1 enhanced the expression of antioxidant genes including nuclear factor erythroid 2-related factor 2 and heme oxygenase-1, while diminishing the expression of the nitrosative protein inducible nitric oxide synthase. JQ1 did not suppress cisplatin-induced apoptosis in A549 nonsmall cell lung cancer cells and AGS gastric cancer cells. These results suggest that JQ1 may protect against cisplatin nephrotoxicity by suppressing DNA damage response, p53, MAP kinases, and oxidative/nitrosative stress pathways.


Author(s):  
Andrew M. Cobb ◽  
Syabira Yusoff ◽  
Robert Hayward ◽  
Sadia Ahmad ◽  
Mengxi Sun ◽  
...  

Objective: The development of ectopic vascular calcification is strongly linked with organismal aging, which is primarily caused by the accumulation of DNA damage over time. As Runx2 (Runt-related transcription factor 2) has been identified as a regulator of vascular smooth muscle cell osteogenic transition, a key component of vascular calcification, we examined the relationship between DNA damage and Runx2 activation. Approach and Results: We found genotoxic stress-stimulated Runx2 accumulation and transactivation of its osteogenic target genes, leading to enhanced calcification. Inhibition of DNA damage signaling attenuated this response. Runx2 localized to sites of DNA damage and participated in DNA repair by regulating phosphorylation events on histone H2AX, with exogenous expression of Runx2 resulting in unrepaired DNA damage and increased apoptosis. Mechanistically, Runx2 was PARylated in response to genotoxic stress, and inhibition of this modification disrupted its localization at DNA lesions and reduced its binding to osteogenic gene promoters. Conclusions: These data identify Runx2 as a novel component of the DNA damage response, coupling DNA damage signaling to both osteogenic gene transcription and apoptosis and providing a mechanism for accelerated mineralization in aging and chronic disease.


2020 ◽  
Vol 31 (5) ◽  
pp. 348-359 ◽  
Author(s):  
Jinrong Feng ◽  
Amjad Islam ◽  
Bjorn Bean ◽  
Jia Feng ◽  
Samantha Sparapani ◽  
...  

Fifty-six strains from the GRACE collection were found to be sensitive to MMS upon repression. Deletion of the HOF1 gene renders sensitivity to genotoxic stress. Hof1 is genetically linked to the Rad53 pathway and is down-regulated in a Rad53-dependent manner. The importance of Hof1 in MMS response is reduced in a Rad23 or Rad4 mutant strain.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1265-1265
Author(s):  
Christine von Klitzing ◽  
Florian Bassermann ◽  
Stephan W. Morris ◽  
Christian Peschel ◽  
Justus Duyster

Abstract The nuclear interaction partner of ALK (NIPA) is a nuclear protein identified by our group in a screen for NPM-ALK interaction partners. We recently reported that NIPA is an F-box protein that assembles with SKP1, Cul1 and Roc1 to establish a novel SCF-type E3 ubiquitin ligase. The formation of the SCFNIPA complex is regulated by cell cycle-dependent phosphorylation of NIPA that restricts SCFNIPA assembly from G1- to late S-phase, thus allowing its substrates to be active from late S-phase throughout mitosis. Proteins involved in cell cycle regulation frequently play a role in DNA damage checkpoints. We therefore sought to determine whether NIPA has a function in the cellular response to genotoxic stress. For this reason we treated NIH/3T3 cells with various DNA-damaging agents. Surprisingly, we observed phosphorylation of NIPA in response to some of these agents, including UV radiation. This phosphorylation was cell cycle phase independent and thus independent of the physiological cell cycle dependent phosphorylation of NIPA. The relevant phosphorylation site is identical to the respective site in the course of cell cycle-dependent phosphorylation of NIPA. Thus, phosphorylation of NIPA upon genotoxic stress would inactivate the SCFNIPA complex in a cell cycle independent manner. Interestingly, this phosphorylation site lies within a consensus site of the Chk1/Chk2 checkpoint kinases. These kinases are central to DNA damage checkpoint signaling. Chk1 is activated by ATR in response to blocked replication forks as they occur after treatment with UV. We performed experiments using the ATM/ATR inhibitor caffeine and the Chk1 inhibitor SB218078 to investigate a potential role of Chk1 in NIPA phosphorylation. Indeed, we found both inhibitors to prevent UV-induced phosphorylation of NIPA. Current experiments applying Chk1 knock-out cells will unravel the role of Chk1 in NIPA phosphorylation. Additional experiments were performed to investigate a function for NIPA in DNA-damage induced apoptosis. In this regard, we observed overexpression of NIPA WT to induce apoptosis in response to UV, whereas no proapoptotic effect was seen with the phosphorylation deficient NIPA mutant. Therefore, the phosphorylated form of NIPA may be involved in apoptotic signaling pathways. In summary, we present data suggesting a cell cycle independent function for NIPA. This activity is involved in DNA damage response and may be involved in regulating apoptosis upon genotoxic stress.


2010 ◽  
Vol 174 (6a) ◽  
pp. 691-702 ◽  
Author(s):  
Lori J. Chappell ◽  
Mary K. Whalen ◽  
Sheena Gurai ◽  
Artem Ponomarev ◽  
Francis A. Cucinotta ◽  
...  

Tumor Biology ◽  
2017 ◽  
Vol 39 (5) ◽  
pp. 101042831769911 ◽  
Author(s):  
Guozhen Wu ◽  
Ning Wang ◽  
Ying Luo ◽  
Yanyan Zhang ◽  
Peng Wang ◽  
...  

Cellular senescence is a key physiological barrier against tumor and represents an option for therapeutic intervention. One pivotal intracellular stimulus causing senescence is DNA damage response, while the senescence-associated heterochromatin in cancer limits the strength of the DNA damage response to endogenous genotoxic stress or DNA-damaging agents. Therefore, targeting the maintenance of compacted chromatin in cancer cells represents an optional intervention to improve the therapeutic efficacy in cancer treatment. Given a crosstalk between methionine cycle and histone methylation, we hypothesize that pharmacologically disrupting methylation potential, defined as the ratio of cellular S-adenosylmethionine to S-adenosylhomocysteine, could affect the chromatin structures in cancer cells and thus enhance their sensitivity to DNA damage response signaling. Our results showed that 3-deazaneplanocin A, a chemical inhibitor of S-adenosylhomocysteine hydrolase, elicited a typical cellular senescence in hepatoma cells. Therapy-induced senescence by 3-deazaneplanocin A was mediated through p53–p21 pathway and triggered by enhanced ataxia-telangiectasia mutated activation related to chromatin changes. In conclusion, our study demonstrated that metabolic perturbation of chromatin status in oncogene-activated cancers could be an optional intervention to sensitize DNA damage response signaling.


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