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break-induced replication

Panagiotis Galanos, George Pappas, Alexander Polyzos, Athanassios Kotsinas, Ioanna Svolaki, Nickolaos N Giakoumakis, Christina Glytsou, Ioannis S Pateras, Umakanta Swain, Vassilis L Souliotis, Alexandros G Georgakilas, Nicholas Geacintov, Luca Scorrano, Claudia Lukas, Jiri Lukas, Zvi Livneh, Zoi Lygerou, Dipanjan Chowdhury, Claus Storgaard Sørensen, Jiri Bartek, Vassilis G Gorgoulis
BACKGROUND: Genomic instability promotes evolution and heterogeneity of tumors. Unraveling its mechanistic basis is essential for the design of appropriate therapeutic strategies. In a previous study, we reported an unexpected oncogenic property of p21WAF1/Cip1 , showing that its chronic expression in a p53-deficient environment causes genomic instability by deregulation of the replication licensing machinery. RESULTS: We now demonstrate that p21WAF1/Cip1 can further fuel genomic instability by suppressing the repair capacity of low- and high-fidelity pathways that deal with nucleotide abnormalities...
March 16, 2018: Genome Biology
Xiubao Chang, Yuexian Hou
Genome editing is a powerful tool to modify a specific gene and to correct a disease-causing mutation. Recently developed new techniques, such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9), significantly facilitate the progression in this field. However, mutations associated with the double strand DNA breaks (DSBs) introduced by these systems hampered their direct usage in clinic. In order to prevent the mutations caused by DSBs, we have designed a novel mean to induce homology-directed recombination (HDR) without DSBs, i...
2018: International Journal of Biochemistry and Molecular Biology
Lorenza Garribba, Wei Wu, Özgün Özer, Rahul Bhowmick, Ian D Hickson, Ying Liu
Our conventional understanding of the process of DNA replication is that it occurs in the S-phase of the cell division cycle. However, during investigations into the mechanism by which common fragile sites (CFSs) drive genome instability, we observed that some DNA synthesis was still occurring in early mitosis at these loci. This curious phenomenon of mitotic DNA synthesis (which we now term "MiDAS") appears to be a form of break-induced DNA replication (BIR), a DNA repair process based on homologous recombination that has been characterized in detail only in lower eukaryotes...
2018: Methods in Enzymology
Rajula Elango, Zachary Kockler, Liping Liu, Anna Malkova
Break-induced replication (BIR) is an important mechanism aimed to repair one-ended double-strand DNA breaks. BIR is initiated by invasion of a broken DNA end into a homologous template followed by DNA synthesis that can proceed for hundreds of kilobases to the end of the chromosome. Unlike S-phase replication, BIR is carried out by a migrating DNA bubble and is associated with conservative inheritance of newly synthesized DNA. The unusual mode of DNA synthesis during BIR leads to an increased level of genetic instabilities including increased mutagenesis and chromosomal rearrangements...
2018: Methods in Enzymology
Gajendrahar Dwivedi, James E Haber
DNA double-strand break (DSB) is a cytotoxic lesion and needs to be repaired immediately. There are several metabolic pathways evolved to repair a DSB. Gene conversion is one of the least error-prone pathway for repair of a DNA DSB. Despite this there is nearly 1000-fold increase in mutation rate associated with gene conversion. Not only higher mutation rate is associated with gene conversion but also there is a very distinct mutation profile compared to spontaneous mutation events. Gene conversion is characterized by the presence of very high frameshift mutation events and other complex mutations that are not present during regular DNA replication...
2018: Methods in Enzymology
Macarena Guijo, María Ceballos-Chávez, Elena Gómez-Marín, Laura Basurto-Cayuela, José C Reyes
Tudor domain containing protein 9 (TDRD9) is a RNA helicase normally expressed in the germline, where it is involved in the biosynthesis of PIWI-interacting RNAs (piRNAs). Here, we show that TDRD9 is highly expressed in a subset of non-small cell lung carcinomas and derived cell lines by hypomethylation of its CpG island. Furthermore, TDRD9 expression is associated with poor prognosis in lung adenocarcinoma. We find that downregulation of TDRD9 expression in TDRD9-positive cell lines causes a decrease in cell proliferation, S-phase cell cycle arrest, and apoptosis...
February 9, 2018: Oncotarget
Judy J Brown, Sarah P Short, Jennifer Stencel-Baerenwald, Kelly Urbanek, Andrea J Pruijssers, Nicole McAllister, Mine Ikizler, Gwen Taylor, Pavithra Aravamudhan, Solomiia Khomandiak, Bana Jabri, Christopher S Williams, Terence S Dermody
Several viruses induce intestinal epithelial cell death during enteric infection. However, it is unclear whether pro-apoptotic capacity promotes or inhibits replication in this tissue. We infected mice with two reovirus strains that infect the intestine but differ in the capacity to alter immunological tolerance to new food antigen. Infection with reovirus strain T1L, which induces an inflammatory immune response to fed antigen, is prolonged in the intestine, whereas T3D-RV, which does not induce this response, is rapidly cleared from the intestine...
March 7, 2018: Journal of Virology
Ragu Kanagasabai, Soumendrakrishna Karmahapatra, Corey A Kientz, Yang Yu, Victor A Hernandez, Evan E Kania, Terry S Elton, Jack C Yalowich
DNA topoisomerase IIα (170 kDa, TOP2α/170) is essential in proliferating cells by resolving DNA topological entanglements during chromosome condensation, replication, and segregation. We previously characterized a C-terminally truncated isoform (TOP2α/90), detectable in human leukemia K562 cells but more abundantly expressed in a clonal subline, K/VP.5, with acquired resistance to the anticancer agent etoposide. TOP2α/90 (786 aa) is the translation product of a TOP2α mRNA which retains a processed intron 19...
March 7, 2018: Molecular Pharmacology
Jason Liang, Bin-Zhong Li, Alexander P Tan, Richard D Kolodner, Christopher D Putnam, Huilin Zhou
Mms21, a subunit of the Smc5/6 complex, possesses an E3 ligase activity for the Small Ubiquitin-like MOdifier (SUMO). Here we show that the mms21-CH mutation, which inactivates Mms21 ligase activity, causes increased accumulation of gross chromosomal rearrangements (GCRs) selected in the dGCR assay. These dGCRs are formed by non-allelic homologous recombination between divergent DNA sequences mediated by Rad52-, Rrm3- and Pol32-dependent break-induced replication. Combining mms21-CH with sgs1Δ caused a synergistic increase in GCRs rates, indicating the distinct roles of Mms21 and Sgs1 in suppressing GCRs...
March 5, 2018: PLoS Genetics
Eui-Hwan Choi, Seobin Yoon, Keun P Kim
Homologous recombination (HR), which ensures accurate DNA replication and strand-break repair, is necessary to preserve embryonic stem cell (ESC) self-renewal. However, little is known about how HR factors modulate ESC differentiation and replication stress-associated DNA breaks caused by unique cell-cycle progression. Here, we report that ESCs utilize Rad51-dependent HR to enhance viability and induce rapid proliferation through a replication-coupled pathway. In addition, ESC differentiation was shown to be enhanced by ectopic expression of a subset of recombinases...
February 8, 2018: Molecular Therapy: the Journal of the American Society of Gene Therapy
Barbara Bukowska, Boleslaw T Karwowski
The clustered DNA lesions are a characteristic feature of ionizing radiation and are defined as two or more damage sites formed within 20 bps after the passage of a single radiation track. The clustered DNA lesions are divided into two major groups: double-stranded breaks (DSBs) and non-DSB clusters also known as Oxidatively-induced Clustered DNA Lesions (OCDLs), which could involve either two opposing strands or the same strand. As irradiation is gaining greater interest in cancer treatment as well as in imaging techniques, the detailed knowledge of its genotoxicity and the mechanisms of repair of radiation-induced DNA damage remain issues to explore...
February 25, 2018: Current Medicinal Chemistry
Morgane Macheret, Thanos D Halazonetis
Oncogene-induced DNA replication stress contributes critically to the genomic instability that is present in cancer. However, elucidating how oncogenes deregulate DNA replication has been impeded by difficulty in mapping replication initiation sites on the human genome. Here, using a sensitive assay to monitor nascent DNA synthesis in early S phase, we identified thousands of replication initiation sites in cells before and after induction of the oncogenes CCNE1 and MYC. Remarkably, both oncogenes induced firing of a novel set of DNA replication origins that mapped within highly transcribed genes...
February 21, 2018: Nature
Sylvia de Pater, Bart J P M Klemann, Paul J J Hooykaas
In recent years, several tools have become available for improved gene-targeting (GT) in plants. DNA breaks at specific sites activate local DNA repair and recombination, including recombination with ectopic sequences leading to GT. Large-scale transformation with the repair template can be avoided by pre-insertion of the repair template in the genome and liberation by sequence-specific nucleases (in planta GT procedure). Here, we tested whether release of the repair template was required for GT. Plants were transformed with constructs encoding a CRISPR/Cas nuclease with a recognition site in the endogenous PPO gene and a repair template harboring a 5' truncated PPO gene with two amino acid substitutions rendering the enzyme insensitive to the herbicide butafenacil...
February 20, 2018: Scientific Reports
Marc-Olivier Turgeon, Nicholas J S Perry, George Poulogiannis
Although there has been a renewed interest in the field of cancer metabolism in the last decade, the link between metabolism and DNA damage/DNA repair in cancer has yet to be appreciably explored. In this review, we examine the evidence connecting DNA damage and repair mechanisms with cell metabolism through three principal links. (1) Regulation of methyl- and acetyl-group donors through different metabolic pathways can impact DNA folding and remodeling, an essential part of accurate double strand break repair...
2018: Frontiers in Oncology
Alexander J Neil, Miranda U Liang, Alexandra N Khristich, Kartik A Shah, Sergei M Mirkin
Expansion of simple DNA repeats is responsible for numerous hereditary diseases in humans. The role of DNA replication, repair and transcription in the expansion process has been well documented. Here we analyzed, in a yeast experimental system, the role of RNA-DNA hybrids in genetic instability of long (GAA)n repeats, which cause Friedreich's ataxia. Knocking out both yeast RNase H enzymes, which counteract the formation of RNA-DNA hybrids, increased (GAA)n repeat expansion and contraction rates when the repetitive sequence was transcribed...
February 13, 2018: Nucleic Acids Research
Zhongcheng Zhou, Lingling Wang, Feixiang Ge, Peng Gong, Hua Wang, Feng Wang, Lingyi Chen, Lin Liu
Embryonic stem cells (ESCs) and meiosis are featured by relatively higher frequent homologous recombination associated with DNA double strand breaks (DSB) repair. Here, we show that Pold3 plays important roles in DSB repair, telomere maintenance and genomic stability of both ESCs and spermatocytes in mice. By attempting to generate Pold3 deficient mice using CRISPR/Cas9 or transcription activator-like effector nucleases, we show that complete loss of Pold3 (Pold3-/-) resulted in early embryonic lethality at E6...
February 13, 2018: Nucleic Acids Research
Pei-Chi Wei, Cheng-Sheng Lee, Zhou Du, Bjoern Schwer, Yuxiang Zhang, Jennifer Kao, Jeffrey Zurita, Frederick W Alt
We recently discovered 27 recurrent DNA double-strand break (DSB) clusters (RDCs) in mouse neural stem/progenitor cells (NSPCs). Most RDCs occurred across long, late-replicating RDC genes and were found only after mild inhibition of DNA replication. RDC genes share intriguing characteristics, including encoding surface proteins that organize brain architecture and neuronal junctions, and are genetically implicated in neuropsychiatric disorders and/or cancers. RDC identification relies on high-throughput genome-wide translocation sequencing (HTGTS), which maps recurrent DSBs based on their translocation to "bait" DSBs in specific chromosomal locations...
February 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
Natalia von Muhlinen, Izumi Horikawa, Fatima Alam, Kazunobu Isogaya, Delphine Lissa, Borek Vojtesek, David P Lane, Curtis C Harris
Cellular senescence is a hallmark of normal aging and aging-related syndromes, including the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS), a rare genetic disorder caused by a single mutation in the LMNA gene that results in the constitutive expression of a truncated splicing mutant of lamin A known as progerin. Progerin accumulation leads to increased cellular stresses including unrepaired DNA damage, activation of the p53 signaling pathway and accelerated senescence. We previously established that the p53 isoforms ∆133p53 and p53β regulate senescence in normal human cells...
February 12, 2018: Oncogene
Kez Cleal, Kevin Norris, Duncan Baird
Telomeres are progressively eroded during repeated rounds of cell division due to the end replication problem but also undergo additional more substantial stochastic shortening events. In most cases, shortened telomeres induce a cell-cycle arrest or trigger apoptosis, although for those cells that bypass such signals during tumour progression, a critical length threshold is reached at which telomere dysfunction may ensue. Dysfunction of the telomere nucleoprotein complex can expose free chromosome ends to the DNA double-strand break (DSB) repair machinery, leading to telomere fusion with both telomeric and non-telomeric loci...
February 6, 2018: International Journal of Molecular Sciences
Ariungerel Gerelchuluun, Junko Maeda, Eri Manabe, Colleen A Brents, Takeji Sakae, Akira Fujimori, David J Chen, Koji Tsuboi, Takamitsu A Kato
Suberoylanilide hydroxamic acid (SAHA) is a histone deacetylase inhibitor, which has been widely utilized throughout the cancer research field. SAHA-induced radiosensitization in normal human fibroblasts AG1522 and lung carcinoma cells A549 were evaluated with a combination of γ-rays, proton, and carbon ion exposure. Growth delay was observed in both cell lines during SAHA treatment; 2 μM SAHA treatment decreased clonogenicity and induced cell cycle block in G1 phase but 0.2 μM SAHA treatment did not show either of them...
February 7, 2018: International Journal of Molecular Sciences
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