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Parp1 nhej

Yifan Chen, Zhaomin Li, Zizheng Dong, Jenny Beebe, Ke Yang, Liwu Fu, Jian-Ting Zhang
: 14-3-3sigma has been implicated in the development of chemo and radiation resistance and in poor prognosis of multiple human cancers. While it has been postulated that 14-3-3sigma contributes to these resistances via inhibiting apoptosis and arresting cells in G2/M phase of the cell cycle, the molecular basis of this regulation is currently unknown. In this study, we tested the hypothesis that 14-3-3sigma causes resistance to DNA-damaging treatments by enhancing DNA repair in cells arrested in G2/M phase following DNA-damaging treatments...
January 13, 2017: Molecular Cancer Research: MCR
Hexi Shen, Gary D Strunks, Bart J P M Klemann, Paul J J Hooykaas, Sylvia de Pater
Double-strand breaks (DSBs) are one of the most harmful DNA lesions. Cells utilize two main pathways for DSB repair: homologous recombination (HR) and nonhomologous end-joining (NHEJ). NHEJ can be subdivided into the KU-dependent classical NHEJ (c-NHEJ) and the more error-prone KU-independent backup-NHEJ (b-NHEJ) pathways, involving the poly (ADP-ribose) polymerases (PARPs). However, in the absence of these factors, cells still seem able to adequately maintain genome integrity, suggesting the presence of other b-NHEJ repair factors or pathways independent from KU and PARPs...
January 5, 2017: G3: Genes—Genomes—Genetics
Ylli Doksani, Titia de Lange
Shelterin protects chromosome ends from the DNA damage response. Although the mechanism of telomere protection has been studied extensively, the fate of double-strand breaks (DSBs) inside telomeres is not known. Here, we report that telomere-internal FokI-induced DSBs activate ATM kinase-dependent signaling in S-phase but are well tolerated and repaired efficiently. Homologous recombination contributes to repair, leading to increased telomere length heterogeneity typical of the alternative lengthening of telomeres (ALT) pathway...
November 1, 2016: Cell Reports
Jiawei Guan, Qian Zhao, Weifeng Mao
PTEN is a tumor suppressor gene characterized as a phosphatase that antagonizes the phosphatidylinositol 3-kinase signaling pathway in the cytoplasm. Nuclear PTEN plays roles in chromosomal stability, in which the double-strand breaks (DSB) repair mediated by homologous recombination (HR) and non-homologous end joining (NHEJ) is critical. Herein, the role of nuclear PTEN in DSB repair and the underlying molecular mechanism was investigated in this study. Using human breast cancer BT549 and MDA-MB-231 cell lines, we reveal a specific feature of PTEN that controls poly(ADP-ribosyl)ation of Ku70 and interferes with binding of Ku70 at DSB...
December 2016: Biochimica et Biophysica Acta
Arlene L Oei, Lianne E M Vriend, Caspar M van Leeuwen, Hans M Rodermond, Rosemarie Ten Cate, Anneke M Westermann, Lukas J A Stalpers, Johannes Crezee, Roland Kanaar, H Petra Kok, Przemek M Krawczyk, Nicolaas A P Franken
Cis-diamminedichloroplatinum(II) (cisplatin, cDDP) is an effective chemotherapeutic agent that induces DNA double strand breaks (DSBs), primarily in replicating cells. Generally, such DSBs can be repaired by the classical or backup non-homologous end joining (c-NHEJ/b-NHEJ) or homologous recombination (HR). Therefore, inhibiting these pathways in cancer cells should enhance the efficiency of cDDP treatments. Indeed, inhibition of HR by hyperthermia (HT) sensitizes cancer cells to cDDP and in the Netherlands this combination is a standard treatment option for recurrent cervical cancer after previous radiotherapy...
August 19, 2016: Oncotarget
Rajib Ghosh, Sanchita Roy, Johan Kamyab, Francoise Dantzer, Sonia Franco
In mammalian cells, chromatin poly(ADP-ribos)ylation (PARylation) at sites of DNA Double-Strand Breaks (DSBs) is mediated by two highly related enzymes, PARP1 and PARP2. However, enzyme-specific genetic interactions with other DSB repair factors remain largely undefined. In this context, it was previously shown that mice lacking PARP1 and H2AX, a histone variant that promotes DSB repair throughout the cell cycle, or the core nonhomologous end-joining (NHEJ) factor Ku80 are not viable, while mice lacking PARP1 and the noncore NHEJ factor DNA-PKcs are severely growth retarded and markedly lymphoma-prone...
September 2016: DNA Repair
Nimrat Chatterjee, Yunfu Lin, Patricia Yotnda, John H Wilson
Multiple pathways modulate the dynamic mutability of trinucleotide repeats (TNRs), which are implicated in neurodegenerative disease and evolution. Recently, we reported that environmental stresses induce TNR mutagenesis via stress responses and rereplication, with more than 50% of mutants carrying deletions or insertions-molecular signatures of DNA double-strand break repair. We now show that knockdown of alt-nonhomologous end joining (alt-NHEJ) components-XRCC1, LIG3, and PARP1-suppresses stress-induced TNR mutagenesis, in contrast to the components of homologous recombination and NHEJ, which have no effect...
July 31, 2016: Journal of Molecular Biology
Agnes Schipler, Veronika Mladenova, Aashish Soni, Vladimir Nikolov, Janapriya Saha, Emil Mladenov, George Iliakis
Chromosome translocations are hallmark of cancer and of radiation-induced cell killing, reflecting joining of incongruent DNA-ends that alter the genome. Translocation-formation requires DNA end-joining mechanisms and incompletely characterized, permissive chromatin conditions. We show that chromatin destabilization by clusters of DNA double-strand-breaks (DSBs) generated by the I-SceI meganuclease at multiple, appropriately engineered genomic sites, compromises c-NHEJ and markedly increases cell killing and translocation-formation compared to single-DSBs...
September 19, 2016: Nucleic Acids Research
Berta N Vazquez, Joshua K Thackray, Nicolas G Simonet, Noriko Kane-Goldsmith, Paloma Martinez-Redondo, Trang Nguyen, Samuel Bunting, Alejandro Vaquero, Jay A Tischfield, Lourdes Serrano
Sirtuins, a family of protein deacetylases, promote cellular homeostasis by mediating communication between cells and environment. The enzymatic activity of the mammalian sirtuin SIRT7 targets acetylated lysine in the N-terminal tail of histone H3 (H3K18Ac), thus modulating chromatin structure and transcriptional competency. SIRT7 deletion is associated with reduced lifespan in mice through unknown mechanisms. Here, we show that SirT7-knockout mice suffer from partial embryonic lethality and a progeroid-like phenotype...
July 15, 2016: EMBO Journal
Julio Castaño, Ana B Herrero, Aldeheid Bursen, Federico González, Rolf Marschalek, Norma C Gutiérrez, Pablo Menendez
The most frequent rearrangement of the human MLL gene fuses MLL to AF4 resulting in high-risk infant B-cell acute lymphoblastic leukemia (B-ALL). MLL fusions are also hallmark oncogenic events in secondary acute myeloid leukemia. They are a direct consequence of mis-repaired DNA double strand breaks (DNA-DSBs) due to defects in the DNA damage response associated with exposure to topoisomerase-II poisons such as etoposide. It has been suggested that MLL fusions render cells susceptible to additional chromosomal damage upon exposure to etoposide...
May 24, 2016: Oncotarget
Carine Robert, Pratik K Nagaria, Nisha Pawar, Adeoluwa Adewuyi, Ivana Gojo, David J Meyers, Philip A Cole, Feyruz V Rassool
Histone deacetylase inhibitors (HDACi) induce acetylation of histone and non-histone proteins, and modulate the acetylation of proteins involved in DNA double-strand break (DSB) repair. Non-homologous end-joining (NHEJ) is one of the main pathways for repairing DSBs. Decreased NHEJ activity has been reported with HDACi treatment. However, mechanisms through which these effects are regulated in the context of chromatin are unclear. We show that pan-HDACi, trichostatin A (TSA), causes differential acetylation of DNA repair factors Ku70/Ku80 and poly ADP-ribose polymerase-1 (PARP1), and impairs NHEJ...
June 2016: Leukemia Research
Rekha Rai, Yong Chen, Ming Lei, Sandy Chang
Repressor/activator protein 1 (RAP1) is a highly conserved telomere-interacting protein. Yeast Rap1 protects telomeres from non-homologous end joining (NHEJ), plays important roles in telomere length control and is involved in transcriptional gene regulation. However, a role for mammalian RAP1 in telomere end protection remains controversial. Here we present evidence that mammalian RAP1 is essential to protect telomere from homology directed repair (HDR) of telomeres. RAP1 cooperates with the basic domain of TRF2 (TRF2(B)) to repress PARP1 and SLX4 localization to telomeres...
2016: Nature Communications
Mihoko Kai
Living cells experience DNA damage as a result of replication errors and oxidative metabolism, exposure to environmental agents (e.g., ultraviolet light, ionizing radiation (IR)), and radiation therapies and chemotherapies for cancer treatments. Accumulation of DNA damage can lead to multiple diseases such as neurodegenerative disorders, cancers, immune deficiencies, infertility, and also aging. Cells have evolved elaborate mechanisms to deal with DNA damage. Networks of DNA damage response (DDR) pathways are coordinated to detect and repair DNA damage, regulate cell cycle and transcription, and determine the cell fate...
February 27, 2016: International Journal of Molecular Sciences
Wei Du, Surya Amarachintha, Andrew F Wilson, Qishen Pang
The prominent role of Fanconi anemia (FA) proteins involves homologous recombination (HR) repair. Poly[ADP-ribose] polymerase1 (PARP1) functions in multiple cellular processes including DNA repair and PARP inhibition is an emerging targeted therapy for cancer patients deficient in HR. Here we show that PARP1 activation in hematopoietic stem and progenitor cells (HSPCs) in response to genotoxic or oxidative stress attenuates HSPC exhaustion. Mechanistically, PARP1 controls the balance between HR and non-homologous end joining (NHEJ) in double strand break (DSB) repair by preventing excessive NHEJ...
February 26, 2016: Scientific Reports
Martijn S Luijsterburg, Inge de Krijger, Wouter W Wiegant, Rashmi G Shah, Godelieve Smeenk, Anton J L de Groot, Alex Pines, Alfred C O Vertegaal, Jacqueline J L Jacobs, Girish M Shah, Haico van Attikum
The response to DNA double-strand breaks (DSBs) requires alterations in chromatin structure to promote the assembly of repair complexes on broken chromosomes. Non-homologous end-joining (NHEJ) is the dominant DSB repair pathway in human cells, but our understanding of how it operates in chromatin is limited. Here, we define a mechanism that plays a crucial role in regulating NHEJ in chromatin. This mechanism is initiated by DNA damage-associated poly(ADP-ribose) polymerase 1 (PARP1), which recruits the chromatin remodeler CHD2 through a poly(ADP-ribose)-binding domain...
February 18, 2016: Molecular Cell
Satish Kumar Tadi, Robin Sebastian, Sumedha Dahal, Ravi K Babu, Bibha Choudhary, Sathees C Raghavan
Mitochondrial DNA (mtDNA) deletions are associated with various mitochondrial disorders. The deletions identified in humans are flanked by short, directly repeated mitochondrial DNA sequences; however, the mechanism of such DNA rearrangements has yet to be elucidated. In contrast to nuclear DNA (nDNA), mtDNA is more exposed to oxidative damage, which may result in double-strand breaks (DSBs). Although DSB repair in nDNA is well studied, repair mechanisms in mitochondria are not characterized. In the present study, we investigate the mechanisms of DSB repair in mitochondria using in vitro and ex vivo assays...
January 15, 2016: Molecular Biology of the Cell
Paul Jacquet, Paul van Buul, Annemarie van Duijn-Goedhart, Karine Reynaud, Jasmine Buset, Mieke Neefs, Arlette Michaux, Pieter Monsieurs, Peter de Boer, Sarah Baatout
At the gastrula phase of development, just after the onset of implantation, the embryo proper is characterized by extremely rapid cell proliferation. The importance of DNA repair is illustrated by embryonic lethality at this stage after ablation of the genes involved. Insight into mutation induction is called for by the fact that women often do not realize they are pregnant, shortly after implantation, a circumstance which may have important consequences when women are subjected to medical imaging using ionizing radiation...
October 2015: Mutation Research. Genetic Toxicology and Environmental Mutagenesis
C-F Chang, P-C Chu, P-Y Wu, M-Y Yu, J-Y Lee, M-D Tsai, M-S Chang
Methylated histone readers are critical for chromatin dynamics, transcription, and DNA repair. Human PHRF1 contains a plant homeodomain (PHD) that recognizes methylated histones and a RING domain, which ubiquitinates substrates. A recent study reveals that PHRF1 is a tumor suppressor that promotes TGF-β cytostatic signaling through TGIF ubiquitination. Also, PHRF1 is a putative phosphorylation substrate of ataxia telangiectasia-mutated/ataxia telangiectasia and Rad3-related kinases; however, the role of PHRF1 in DNA damage response is unclear...
2015: Cell Death & Disease
Nidal Muvarak, Shannon Kelley, Carine Robert, Maria R Baer, Danilo Perrotti, Carlo Gambacorti-Passerini, Curt Civin, Kara Scheibner, Feyruz V Rassool
UNLABELLED: Leukemias expressing the constitutively activated tyrosine kinases (TK) BCR-ABL1 and FLT3/ITD activate signaling pathways that increase genomic instability through generation of reactive oxygen species (ROS), DNA double-strand breaks (DSB), and error-prone repair. The nonhomologous end-joining (NHEJ) pathway is a major pathway for DSB repair and is highly aberrant in TK-activated leukemias; an alternative form of NHEJ (ALT-NHEJ) predominates, evidenced by increased expression of DNA ligase IIIα (LIG3) and PARP1, increased frequency of large genomic deletions, and repair using DNA sequence microhomologies...
April 2015: Molecular Cancer Research: MCR
S Sharma, S M Javadekar, M Pandey, M Srivastava, R Kumari, S C Raghavan
Nonhomologous DNA end joining (NHEJ) is one of the major double-strand break (DSB) repair pathways in higher eukaryotes. Recently, it has been shown that alternative NHEJ (A-NHEJ) occurs in the absence of classical NHEJ and is implicated in chromosomal translocations leading to cancer. In the present study, we have developed a novel biochemical assay system utilizing DSBs flanked by varying lengths of microhomology to study microhomology-mediated alternative end joining (MMEJ). We show that MMEJ can operate in normal cells, when microhomology is present, irrespective of occurrence of robust classical NHEJ...
March 19, 2015: Cell Death & Disease
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