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Ruobo Zhou, Olivia Yang, Anne-Cécile Déclais, Hyeonseok Jin, Gwang Hyeon Gwon, Alasdair D J Freeman, Yunje Cho, David M J Lilley, Taekjip Ha
Holliday junction (HJ) resolution by resolving enzymes is essential for chromosome segregation and recombination-mediated DNA repair. HJs undergo two types of structural dynamics that determine the outcome of recombination: conformer exchange between two isoforms and branch migration. However, it is unknown how the preferred branch point and conformer are achieved between enzyme binding and HJ resolution given the extensive binding interactions seen in static crystal structures. Single-molecule fluorescence resonance energy transfer analysis of resolving enzymes from bacteriophages (T7 endonuclease I), bacteria (RuvC), fungi (GEN1) and humans (hMus81-Eme1) showed that both types of HJ dynamics still occur after enzyme binding...
January 21, 2019: Nature Chemical Biology
Jean-Hugues Guervilly, Pierre Henri Gaillard
The SLX4/FANCP tumor suppressor has emerged as a key player in the maintenance of genome stability, making pivotal contributions to the repair of interstrand cross-links, homologous recombination, and in response to replication stress genome-wide as well as at specific loci such as common fragile sites and telomeres. SLX4 does so in part by acting as a scaffold that controls and coordinates the XPF-ERCC1, MUS81-EME1, and SLX1 structure-specific endonucleases in different DNA repair and recombination mechanisms...
October 2018: Critical Reviews in Biochemistry and Molecular Biology
Meret Arter, Vanesa Hurtado-Nieves, Ashwini Oke, Tangna Zhuge, Rahel Wettstein, Jennifer C Fung, Miguel G Blanco, Joao Matos
During meiosis, crossover recombination promotes the establishment of physical connections between homologous chromosomes, enabling their bipolar segregation. To ensure that persistent recombination intermediates are disengaged prior to the completion of meiosis, the Yen1(GEN1) resolvase is strictly activated at the onset of anaphase II. Whether controlled activation of Yen1 is important for meiotic crossing-over is unknown. Here, we show that CDK-mediated phosphorylation of Yen1 averts its pervasive recruitment to recombination intermediates during prophase I...
June 18, 2018: Developmental Cell
Swastika Sanyal, Lucia Molnarova, Judita Richterova, Barbora Huraiova, Zsigmond Benko, Silvia Polakova, Ingrid Cipakova, Andrea Sevcovicova, Katarina Gaplovska-Kysela, Karl Mechtler, Lubos Cipak, Juraj Gregan
The canonical role of cohesin is to mediate sister chromatid cohesion. In addition, cohesin plays important roles in processes such as DNA repair and regulation of gene expression. Mounting evidence suggests that various post-translational modifications, including phosphorylation, acetylation and sumoylation regulate cohesin functions. Our mass spectrometry analysis of cohesin purified from Schizosaccharomyces pombe cells revealed that the cohesin subunit Psm1 is methylated on two evolutionarily conserved lysine residues, K536 and K1200...
July 6, 2018: Journal of Cell Science
Anita Palma, Giusj Monia Pugliese, Ivana Murfuni, Veronica Marabitti, Eva Malacaria, Sara Rinalducci, Anna Minoprio, Massimo Sanchez, Filomena Mazzei, Lello Zolla, Annapaola Franchitto, Pietro Pichierri
The MUS81 complex is crucial for preserving genome stability through the resolution of branched DNA intermediates in mitosis. However, untimely activation of the MUS81 complex in S-phase is dangerous. Little is known about the regulation of the human MUS81 complex and how deregulated activation affects chromosome integrity. Here, we show that the CK2 kinase phosphorylates MUS81 at Serine 87 in late-G2/mitosis, and upon mild replication stress. Phosphorylated MUS81 interacts with SLX4, and this association promotes the function of the MUS81 complex...
June 1, 2018: Nucleic Acids Research
T P MacGregor, R Carter, R S Gillies, J M Findlay, C Kartsonaki, F Castro-Giner, N Sahgal, L M Wang, R Chetty, N D Maynard, J B Cazier, F Buffa, P J McHugh, I Tomlinson, M R Middleton, R A Sharma
Oxaliplatin-based chemotherapy is used to treat patients with esophageal adenocarcinoma (EAC), but no biomarkers are currently available for patient selection. We performed a prospective, clinical trial to identify potential biomarkers associated with clinical outcomes. Tumor tissue was obtained from 38 patients with resectable EAC before and after 2 cycles of oxaliplatin-fluorouracil chemotherapy. Pre-treatment mRNA expression of 280 DNA repair (DNAR) genes was tested for association with histopathological regression at surgery, disease-free survival (DFS) and overall survival (OS)...
May 8, 2018: Scientific Reports
Huong Thi Thu Phung, Hoa Luong Hieu Nguyen, Sang Thanh Vo, Dung Hoang Nguyen, Minh Van Le
Mus81 is a well-conserved DNA structure-specific endonuclease which belongs to the XPF/Rad1 family of proteins that are involved in DNA nucleotide excision repair. Mus81 forms a heterodimer with a non-catalytic subunit, Mms4, in Saccharomyces cerevisiae (Eme1/EME1 in Schizosaccharomyces pombe and mammals). Recent evidence shows that Mus81 functions redundantly with Sgs1, a member of the ubiquitous RecQ family of DNA helicases, to process toxic recombinant intermediates. In budding yeast, homologous recombination is regulated by the Rad52 epistasis group of proteins, including Rad52, which stimulates the main steps of DNA sequence-homology searching...
September 2018: Yeast
Özgün Özer, Rahul Bhowmick, Ying Liu, Ian D Hickson
Telomeres resemble common fragile sites (CFSs) in that they are difficult-to-replicate and exhibit fragility in mitosis in response to DNA replication stress. At CFSs, this fragility is associated with a delay in the completion of DNA replication until early mitosis, whereupon cells are proposed to switch to a RAD52-dependent form of break-induced replication. Here, we show that this mitotic DNA synthesis (MiDAS) is also a feature of human telomeres. Telomeric MiDAS is not restricted to those telomeres displaying overt fragility, and is a feature of a wide range of cell lines irrespective of whether their telomeres are maintained by telomerase or by the alternative lengthening of telomeres (ALT) mechanism...
March 23, 2018: Oncotarget
Stephen C West, Ying Wai Chan
The efficient processing of homologous recombination (HR) intermediates, which often contain four-way structures known as Holliday junctions (HJs), is required for proper chromosome segregation at mitosis. Eukaryotic cells possess three distinct pathways of resolution: (i) HJ dissolution mediated by BLM-topoisomerase IIIα-RMI1-RMI2 (BTR) complex, and HJ resolution catalyzed by either (ii) SLX1-SLX4-MUS81-EME1-XPF-ERCC1 (SMX complex) or (iii) GEN1. The BTR pathway acts at all times throughout the cell cycle, whereas the actions of SMX and GEN1 are restrained in S phase and become elevated late in the cell cycle to ensure the resolution of persistent recombination intermediates before mitotic division...
2017: Cold Spring Harbor Symposia on Quantitative Biology
Arancha Sanchez, Mariana C Gadaleta, Oliver Limbo, Paul Russell
The DNA repair enzyme polynucleotide kinase/phosphatase (PNKP) protects genome integrity by restoring ligatable 5'-phosphate and 3'-hydroxyl termini at single-strand breaks (SSBs). In humans, PNKP mutations underlie the neurological disease known as MCSZ, but these individuals are not predisposed for cancer, implying effective alternative repair pathways in dividing cells. Homology-directed repair (HDR) of collapsed replication forks was proposed to repair SSBs in PNKP-deficient cells, but the critical HDR protein Rad51 is not required in PNKP-null (pnk1Δ) cells of Schizosaccharomyces pombe...
September 2017: PLoS Genetics
Ed Dicks, Honglin Song, Susan J Ramus, Elke Van Oudenhove, Jonathan P Tyrer, Maria P Intermaggio, Siddhartha Kar, Patricia Harrington, David D Bowtell, Aocs Study Group, Mine S Cicek, Julie M Cunningham, Brooke L Fridley, Jennifer Alsop, Mercedes Jimenez-Linan, Anna Piskorz, Teodora Goranova, Emma Kent, Nadeem Siddiqui, James Paul, Robin Crawford, Samantha Poblete, Shashi Lele, Lara Sucheston-Campbell, Kirsten B Moysich, Weiva Sieh, Valerie McGuire, Jenny Lester, Kunle Odunsi, Alice S Whittemore, Natalia Bogdanova, Matthias Dürst, Peter Hillemanns, Beth Y Karlan, Aleksandra Gentry-Maharaj, Usha Menon, Marc Tischkowitz, Douglas Levine, James D Brenton, Thilo Dörk, Ellen L Goode, Simon A Gayther, D P Paul Pharoah
We analyzed whole exome sequencing data in germline DNA from 412 high grade serous ovarian cancer (HGSOC) cases from The Cancer Genome Atlas Project and identified 5,517 genes harboring a predicted deleterious germline coding mutation in at least one HGSOC case. Gene-set enrichment analysis showed enrichment for genes involved in DNA repair (p = 1.8×10-3 ). Twelve DNA repair genes - APEX1, APLF, ATX, EME1, FANCL, FANCM, MAD2L2, PARP2, PARP3, POLN, RAD54L and SMUG1 - were prioritized for targeted sequencing in up to 3,107 HGSOC cases, 1,491 cases of other epithelial ovarian cancer (EOC) subtypes and 3,368 unaffected controls of European origin...
August 1, 2017: Oncotarget
Irene Saugar, Alberto Jiménez-Martín, José Antonio Tercero
Structure-specific endonucleases contribute to the maintenance of genome integrity by cleaving DNA intermediates that need to be resolved for faithful DNA repair, replication, or recombination. Despite advances in the understanding of their function and regulation, it is less clear how these proteins respond to genotoxic stress. Here, we show that the structure-specific endonuclease Mus81-Mms4/EME1 relocalizes to subnuclear foci following DNA damage and colocalizes with the endonucleases Rad1-Rad10 (XPF-ERCC1) and Slx1-Slx4...
August 15, 2017: Cell Reports
Stefano Di Marco, Zdenka Hasanova, Radhakrishnan Kanagaraj, Nagaraja Chappidi, Veronika Altmannova, Shruti Menon, Hana Sedlackova, Jana Langhoff, Kalpana Surendranath, Daniela Hühn, Rahul Bhowmick, Victoria Marini, Stefano Ferrari, Ian D Hickson, Lumir Krejci, Pavel Janscak
The MUS81-EME1 endonuclease cleaves late replication intermediates at common fragile sites (CFSs) during early mitosis to trigger DNA-repair synthesis that ensures faithful chromosome segregation. Here, we show that these DNA transactions are promoted by RECQ5 DNA helicase in a manner dependent on its Ser727 phosphorylation by CDK1. Upon replication stress, RECQ5 associates with CFSs in early mitosis through its physical interaction with MUS81 and promotes MUS81-dependent mitotic DNA synthesis. RECQ5 depletion or mutational inactivation of its ATP-binding site, RAD51-interacting domain, or phosphorylation site causes excessive binding of RAD51 to CFS loci and impairs CFS expression...
June 1, 2017: Molecular Cell
Haley D M Wyatt, Rob C Laister, Stephen R Martin, Cheryl H Arrowsmith, Stephen C West
The efficient removal of replication and recombination intermediates is essential for the maintenance of genome stability. Resolution of these potentially toxic structures requires the MUS81-EME1 endonuclease, which is activated at prometaphase by formation of the SMX tri-nuclease containing three DNA repair structure-selective endonucleases: SLX1-SLX4, MUS81-EME1, and XPF-ERCC1. Here we show that SMX tri-nuclease is more active than the three individual nucleases, efficiently cleaving replication forks and recombination intermediates...
March 2, 2017: Molecular Cell
Chong Wang, James D Higgins, Yi He, Pingli Lu, Dabing Zhang, Wanqi Liang
Yen1/GEN1 are canonical Holliday junction resolvases that belong to the RAD2/XPG family. In eukaryotes, such as budding yeast, mice, worms, and humans, Yen1/GEN1 work together with Mus81-Mms4/MUS81-EME1 and Slx1-Slx4/SLX1-SLX4 in DNA repair by homologous recombination to maintain genome stability. In plants, the biological function of Yen1/GEN1 remains largely unclear. In this study, we characterized the loss of function mutants of OsGEN1 and OsSEND1, a pair of paralogs of Yen1/GEN1 in rice (Oryza sativa). We first investigated the role of OsGEN1 during meiosis and found a reduction in chiasma frequency by ∼6% in osgen1 mutants, compared to the wild type, suggesting a possible involvement of OsGEN1 in the formation of crossovers...
February 2017: Plant Physiology
Rahul Bhowmick, Sheroy Minocherhomji, Ian D Hickson
Homologous recombination (HR) is necessary to counteract DNA replication stress. Common fragile site (CFS) loci are particularly sensitive to replication stress and undergo pathological rearrangements in tumors. At these loci, replication stress frequently activates DNA repair synthesis in mitosis. This mitotic DNA synthesis, termed MiDAS, requires the MUS81-EME1 endonuclease and a non-catalytic subunit of the Pol-delta complex, POLD3. Here, we examine the contribution of HR factors in promoting MiDAS in human cells...
December 15, 2016: Molecular Cell
Maral Adel Fahmideh, Catharina Lavebratt, Joachim Schüz, Martin Röösli, Tore Tynes, Michael A Grotzer, Christoffer Johansen, Claudia E Kuehni, Birgitta Lannering, Michaela Prochazka, Lisbeth S Schmidt, Maria Feychting
Knowledge on the role of genetic polymorphisms in the etiology of pediatric brain tumors (PBTs) is limited. Therefore, we investigated the association between single nucleotide polymorphisms (SNPs), identified by candidate gene-association studies on adult brain tumors, and PBT risk.The study is based on the largest series of PBT cases to date. Saliva DNA from 245 cases and 489 controls, aged 7-19 years at diagnosis/reference date, was genotyped for 68 SNPs. Data were analyzed using unconditional logistic regression...
September 27, 2016: Oncotarget
Xiaowen Wang, Herui Wang, Bin Guo, Ya Zhang, Yinv Gong, Chi Zhang, Hong Xu, Xiaohui Wu
Resolution of the Holliday junction (HJ) is essential for homologous recombination and DNA repair. In Saccharomyces cerevisiae, HJ resolvase Yen1 and the Mus81-Mms4 complex are redundant in DNA damage repair. In cultured mammalian cells, such redundancy also exists between Yen1 ortholog GEN1 and the Mus81-Mms1 ortholog MUS81-EME1. In this report, we further tested if GEN1 and EME1 redundantly affect HJ-related physiological processes in mice. We found that combined homozygous mutations of Gen1 and Eme1 led to synthetic lethality during early embryonic stages...
October 2016: DNA and Cell Biology
Xiaohong Zhou, Maria DeLucia, Jinwoo Ahn
Evolutionarily conserved structure-selective endonuclease MUS81 forms a complex with EME1 and further associates with another endonuclease SLX4-SLX1 to form a four-subunit complex of MUS81-EME1-SLX4-SLX1, coordinating distinctive biochemical activities of both endonucleases in DNA repair. Viral protein R (Vpr), a highly conserved accessory protein in primate lentiviruses, was previously reported to bind SLX4 to mediate down-regulation of MUS81. However, the detailed mechanism underlying MUS81 down-regulation is unclear...
August 12, 2016: Journal of Biological Chemistry
R Carter, A Westhorpe, M J Romero, A Habtemariam, C R Gallevo, Y Bark, N Menezes, P J Sadler, R A Sharma
Some of the largest improvements in clinical outcomes for patients with solid cancers observed over the past 3 decades have been from concurrent treatment with chemotherapy and radiotherapy (RT). The lethal effects of RT on cancer cells arise primarily from damage to DNA. Ruthenium (Ru) is a transition metal of the platinum group, with potentially less toxicity than platinum drugs. We postulated that ruthenium-arene complexes are radiosensitisers when used in combination with RT. We screened 14 ruthenium-arene complexes and identified AH54 and AH63 as supra-additive radiosensitisers by clonogenic survival assays and isobologram analyses...
February 12, 2016: Scientific Reports
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