المؤلفون: Camilla Trovesi, Michela Clerici, Maria Pia Longhese, Alessandro Galbiati, Giovanna Lucchini

المساهمون: Clerici, M, Trovesi, C, Galbiati, A, Lucchini, G, Longhese, M

المصدر: The EMBO Journal.

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, Checkpoint, Double‐Strand Break, Mec1, Resection, Tel1, genetic processes, Saccharomyces cerevisiae, Mutant, DNA, Single-Stranded, BIO/18 - GENETICA, Protein Serine-Threonine Kinases, medicine.disease_cause, DNA-binding protein, General Biochemistry, Genetics and Molecular Biology, chemistry.chemical_compound, medicine, DNA Breaks, Double-Stranded, Molecular Biology, Mutation, General Immunology and Microbiology, biology, General Neuroscience, fungi, Intracellular Signaling Peptides and Proteins, Articles, biology.organism_classification, Molecular biology, Cell biology, enzymes and coenzymes (carbohydrates), MRX complex, chemistry, health occupations, biological phenomena, cell phenomena, and immunity, Signal transduction, Chromatin immunoprecipitation, DNA, Signal Transduction

الوصف: Tel1/ATM and Mec1/ATR checkpoint kinases are activated by DNA double-strand breaks (DSBs). Mec1/ATR recruitment to DSBs requires the formation of RPA-coated single-stranded DNA (ssDNA), which arises from 5′–3′ nucleolytic degradation (resection) of DNA ends. Here, we show that Saccharomyces cerevisiae Mec1 regulates resection of the DSB ends. The lack of Mec1 accelerates resection and reduces the loading to DSBs of the checkpoint protein Rad9, which is known to inhibit ssDNA generation. Extensive resection is instead inhibited by the Mec1-ad mutant variant that increases the recruitment near the DSB of Rad9, which in turn blocks DSB resection by both Rad53-dependent and Rad53-independent mechanisms. The mec1-ad resection defect leads to prolonged persistence at DSBs of the MRX complex that causes unscheduled Tel1 activation, which in turn impairs checkpoint switch off. Thus, Mec1 regulates the generation of ssDNA at DSBs, and this control is important to coordinate Mec1 and Tel1 signaling activities at these breaks.

وصف الملف: STAMPA

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6c6ab3f335c334a204c0116e3c99969bTest
https://doi.org/10.1002/embj.201386041Test

المؤلفون: Teng Ma, Xiaochun Yu, Feng Zhang

المصدر: Journal of cell science. 126(Pt 21)

مصطلحات موضوعية: Ribosomal Proteins, DNA clamp, DNA Repair, DNA damage, Integrator complex, DNA repair, Tumor Suppressor Proteins, Short Report, RNA-Binding Proteins, Cell Biology, Biology, Molecular biology, Cell biology, DNA-Binding Proteins, Mitochondrial Proteins, MRX complex, MRN complex, Integrator Complex Subunit 6, Cell Line, Tumor, Humans, Replication protein A, DNA Damage, Protein Binding

الوصف: Human single-stranded DNA-binding protein 1 (hSSB1) plays an important role in the DNA damage response and the maintenance of genomic stability. It has been shown that the core hSSB1 complex contains hSSB1, INTS3 and C9orf80. Using protein affinity purification, we have identified integrator complex subunit 6 (INTS6) as a major subunit of the core hSSB1 complex. INTS6 forms a stable complex with INTS3 and hSSB1 both in vitro and in vivo. In this complex, INTS6 directly interacts with INTS3. In response to the DNA damage response, along with INTS3 and hSSB1, INTS6 relocates to the DNA damage sites. Moreover, the hSSB1–INTS complex regulates the accumulation of RAD51 and BRCA1 at DNA damage sites and the correlated homologous recombination.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0b06509336955aa4b1a4b6ab8c2592e6Test
https://pubmed.ncbi.nlm.nih.gov/23986477Test

المؤلفون: Bonnie K. Baxter, John H.J. Petrini, Debra A. Bressan

المصدر: Molecular and Cellular Biology. 19:7681-7687

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, Mitotic crossover, DNA Repair, Macromolecular Substances, DNA repair, FLP-FRT recombination, Saccharomyces cerevisiae, Biology, Radiation Tolerance, Fungal Proteins, Homology directed repair, Animals, Interphase, Molecular Biology, Recombination, Genetic, Endodeoxyribonucleases, Cell Biology, DNA repair protein XRCC4, DNA Dynamics and Chromosome Structure, Molecular biology, DNA-Binding Proteins, Non-homologous end joining, enzymes and coenzymes (carbohydrates), Exodeoxyribonucleases, MRX complex, Gamma Rays, Mutation, biological phenomena, cell phenomena, and immunity, Mating Factor, Peptides, Homologous recombination, Gene Deletion

الوصف: Saccharomyces cerevisiae mre11Delta mutants are profoundly deficient in double-strand break (DSB) repair, indicating that the Mre11-Rad50-Xrs2 protein complex plays a central role in the cellular response to DNA DSBs. In this study, we examined the role of the complex in homologous recombination, the primary mode of DSB repair in yeast. We measured survival in synchronous cultures following irradiation and scored sister chromatid and interhomologue recombination genetically. mre11Delta strains were profoundly sensitive to ionizing radiation (IR) throughout the cell cycle. Mutant strains exhibited decreased frequencies of IR-induced sister chromatid and interhomologue recombination, indicating a general deficiency in homologous recombination-based DSB repair. Since a nuclease-deficient mre11 mutant was not impaired in these assays, it appears that the role of the S. cerevisiae Mre11-Rad50-Xrs2 protein complex in facilitating homologous recombination is independent of its nuclease activities.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6c07ddfa55195da5a5ba180f3794a0b8Test
https://doi.org/10.1128/mcb.19.11.7681Test

المؤلفون: Dirk C. Winter, Elizabeth Y. Choe, Rong Li

المصدر: Proceedings of the National Academy of Sciences. 96:7288-7293

مصطلحات موضوعية: Protein subunit, Genes, Fungal, Molecular Sequence Data, Saccharomyces cerevisiae, Arp2/3 complex, Acanthamoeba, macromolecular substances, Fungal Proteins, Structure-Activity Relationship, Animals, Humans, Actin, Sequence Deletion, Multidisciplinary, Base Sequence, biology, Biological Sciences, biology.organism_classification, Actins, Yeast, Cell biology, Cytoskeletal Proteins, MRX complex, Actin-Related Protein 3, Actin-Related Protein 2, biology.protein, Cyclin-dependent kinase complex, Sequence Analysis, Protein Binding

الوصف: In previous work, we identified the yeast Arp2/3 complex, which localizes to cortical actin patches and is required for their motility and integrity in vivo . This complex contains proteins homologous to each subunit of the Acanthamoeba and human Arp2/3 complex except for a 40-kDa subunit (p40), which was missing from the purified yeast complex. Here, we demonstrate by using immunoprecipitation and gel-filtration analysis that Arc40p, the homolog of p40 identified from the yeast genome database, associates with the yeast Arp2/3 complex. We have carried out gene disruptions of each subunit of the yeast Arp2/3 complex to study each subunit’s role in the function of the complex. Surprisingly, we find that only ARC40 is fully essential for cell viability. Strains lacking each of the other subunits exhibit varying degrees of defects in cell growth and viability and in assembly and polarization of cortical actin patches. We have also examined each subunit’s role in maintaining the structural integrity of the Arp2/3 complex. Arp2p, Arp3p, and Arc40p fall into the monomer pool in Δarc19 and Δarc35 cells, suggesting that Arc19p and Arc35p are the central scaffolding components of the complex. Arp2p and Arp3p do not have major roles in maintaining complex integrity, and Arc15p is required for association of Arp2p and Arc40p, but not other subunits, with the complex. These results provide evidence that each subunit contributes differently to the assembly and function of the Arp2/3 complex.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::984dc6f34bcbd168cb3dc37ed666db80Test
https://doi.org/10.1073/pnas.96.13.7288Test

المؤلفون: Tanya T. Paull, Martin Gellert

المصدر: Genes & Development. 13:1276-1288

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, Time Factors, DNA Repair, DNA repair, Recombinant Fusion Proteins, DNA, Single-Stranded, Cell Cycle Proteins, Eukaryotic DNA replication, Fungal Proteins, Endonuclease, Mre11 complex, chemistry.chemical_compound, Adenosine Triphosphate, MRE11 Homologue Protein, Genetics, Humans, Ku Autoantigen, Gene Library, Endodeoxyribonucleases, biology, DNA Helicases, Nuclear Proteins, Antigens, Nuclear, DNA, Endonucleases, Cell biology, DNA-Binding Proteins, enzymes and coenzymes (carbohydrates), Exodeoxyribonucleases, MRX complex, Biochemistry, chemistry, biology.protein, biological phenomena, cell phenomena, and immunity, Homologous recombination, HeLa Cells, Research Paper, Developmental Biology

الوصف: The Nijmegen breakage syndrome gene product (Nbs1) was shown recently to associate in vivo with the Mre11 and Rad50 proteins, which play pivotal roles in eukaryotic DNA double-strand break repair, meiotic recombination, and telomere maintenance. We show in this work that the triple complex of recombinant Nbs1, Mre11, and Rad50 proteins binds cooperatively to DNA and forms a distinct protein–DNA species. The Mre11/Rad50/Nbs1 complex displays several enzymatic activities that are not seen without Nbs1, including partial unwinding of a DNA duplex and efficient cleavage of fully paired hairpins. Unwinding and hairpin cleavage are both increased by the presence of ATP. On nonhairpin DNA ends, ATP controls a switch in endonuclease specificity that allows Mre11/Rad50/Nbs1 to cleave a 3′-protruding strand at a double-/single-strand transition. Mutational analysis demonstrates that Rad50 is responsible for ATP binding by the complex, but the ATP-dependent activities are expressed only with Nbs1 present.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::40af56862cc75e06a13d3e7a6b665bb3Test
https://doi.org/10.1101/gad.13.10.1276Test

المؤلفون: Xing Wang Deng, Tomohiko Tsuge, Minami Matsui, Daniel A. Chamovitz, Avital Yahalom, S F Kwok, Baruch Karniol

المصدر: FEBS Letters. 439:173-179

مصطلحات موضوعية: Genetics, Protein subunit, Nuclear cap-binding protein complex, Biophysics, Cell Biology, Biology, biology.organism_classification, Biochemistry, COP9 Signalosome Complex, F-box protein, Cell biology, MRX complex, Structural Biology, Arabidopsis, TRAMP complex, Cyclin-dependent kinase complex, biology.protein, Molecular Biology

الوصف: The Arabidopsis COP9 complex is a multi-subunit repressor of photomorphogenesis which is conserved among multicellular organisms. Approximately 12 proteins copurify with the COP9 complex. Seven of these proteins are orthologues of subunits of the recently published mammalian COP9 complex. Four of the proteins show amino acid similarity to various subunits of the COP9 complex, eIF3 complex and 19S cap of the proteasome. We have studied one of these proteins in order to determine if it is a component of the COP9 complex. Arabidopsis p105 is highly similar to the p110 subunit of the human eIF3. The p105 gene is induced during photomorphogenesis, and RNA and protein analysis reveal different tissue accumulation patterns. p105 is found in a large protein complex. p105 interacts in yeast with both COP9 and FUS6, two known components of the COP9 complex. Our results indicate that p105 is not a component of the COP9 core complex, though it may interact with components of the complex.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::8dc49148ce44d862c15c416b6edcc1ccTest
https://doi.org/10.1016/s0014-5793Test(98)01367-2

المؤلفون: Tsutomu Ohta, Jun-ichi Tomizawa, Takehiko Usui, Hideyuki Ogawa, Hiroyuki Oshiumi, Tomoko Ogawa

المصدر: Cell. 95:705-716

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, DNA Repair, DNA repair, Guinea Pigs, genetic processes, Saccharomyces cerevisiae, DNA-binding protein, General Biochemistry, Genetics and Molecular Biology, Fungal Proteins, Mre11 complex, MRE11 Homologue Protein, Animals, Endodeoxyribonucleases, Recombination, Genetic, Genetics, Nuclease, biology, Biochemistry, Genetics and Molecular Biology(all), fungi, Cell biology, DNA-Binding Proteins, Meiosis, enzymes and coenzymes (carbohydrates), Exodeoxyribonucleases, MRX complex, health occupations, biology.protein, Rabbits, Chromosomes, Fungal, biological phenomena, cell phenomena, and immunity, Homologous recombination

الوصف: Meiotic recombination of S. cerevisiae contains two temporally coupled processes, formation and processing of double-strand breaks (DSBs). Mre11 forms a complex with Rad50 and Xrs2, acting as the binding core, and participates in DSB processing. Although these proteins are also involved in DSB formation, Mre11 is not necessarily holding them. The C-terminal region of Mre11 is required only for DSB formation and binds to some meiotic proteins. The N-terminal half specifies nuclease activities that are collectively required for DSB processing. Mre11 has a DNA-binding site for DSB formation and another site for DSB processing. It has two regions to bind to Rad50. Mre11 repairs methyl methanesulfonate–induced DSBs by reactions that require the nuclease activities and those that do not.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::39ecb0a12fa62887084d2d0f111881faTest
https://doi.org/10.1016/s0092-8674Test(00)81640-2

المؤلفون: James E. Haber

المصدر: Cell. 95(5):583-586

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, DNA Repair, DNA repair, DNA damage, Biology, General Biochemistry, Genetics and Molecular Biology, Fungal Proteins, Mre11 complex, MRE11 Homologue Protein, Yeasts, medicine, Animals, Humans, Genetics, Fungal protein, Endodeoxyribonucleases, Biochemistry, Genetics and Molecular Biology(all), medicine.disease, Molecular biology, Acid Anhydride Hydrolases, DNA-Binding Proteins, DNA Repair Enzymes, Exodeoxyribonucleases, MRX complex, Homologous recombination, Pseudogenes, Nijmegen breakage syndrome, DNA Damage

الوصف: This year, the Mre11 complex has attracted a new group of aficionados interested in cancer and in checkpoint regulation. In humans, the p95 component is mutated in Nijmegen breakage syndrome (NBS), a condition that has similarities with ataxia telangiectasia, including ionizing radiation-sensitivity, cancer predisposition, and a failure to arrest at G1/S in response to DNA damage (5xCarney, J.P, Maser, R.S, Olivares, H, Davis, E.M, Le Beau, M, Yates, J.R III, Hays, L, Morgan, W.F, and Petrini, J.H. Cell. 1998; 93: 477–486Abstract | Full Text | Full Text PDF | PubMed | Scopus (858)See all References, 26xVaron, R, Vissinga, C, Platzer, M, Cerosaletti, K.M, Chrzanowska, K.H, Saar, K, Beckmann, G, Seemanova, E, Cooper, P.R, Nowak, N.J et al. Cell. 1998; 93: 467–476Abstract | Full Text | Full Text PDF | PubMed | Scopus (725)See all References). Possibly, Mre11/Rad50/NBS binds to DSB ends and signals the presence of that damage.An alternative possibility is that the signal of DNA damage is the extent of single-stranded DNA produced by the exonuclease activity of the Mre11 complex. In Saccharomyces, evidence supporting this idea has come not from studying the ability of cells to arrest after DNA damage, but from their capacity to adapt and resume growth when damage persists. Two DSBs are sufficient to discourage a wild-type yeast cell from adapting to checkpoint-induced G2/M arrest, but this permanent arrest is suppressed by an mre11 or rad50 deletion that reduces the extent of single-stranded DNA (Lee et al. 1998xLee, S.-E, Moore, J.K, Holmes, A, Umezu, K, Kolodner, R, and Haber, J.E. Cell. 1998; 94: 399–409Abstract | Full Text | Full Text PDF | PubMed | Scopus (520)See all ReferencesLee et al. 1998).There is no doubt that Mre11p is attracted to the sites of DNA damage, for repair and possibly as part of the damage-signaling apparatus. Following irradiation, foci containing both Mre11p and Rad50p have been seen in mammalian cells and in yeast. A stunning series of micrographs illustrating this point were published by Nelms et al. 1998xNelms, B.E, Maser, R.S, MacKay, J.F, Lagally, M.G, and Petrini, J.H. Science. 1998; 280: 590–592Crossref | PubMed | Scopus (376)See all ReferencesNelms et al. 1998, who examined mammalian nuclei irradiated with ultrasoft X-rays passed through a grid that produced stripes of DNA damage. The remarkable finding was not that hMre11p was localized within the irradiated regions, but that in repair-defective cells these stripes persisted for hours, suggesting that the damaged DNA was not diffusing around the nucleus. Interestingly, these foci do not attract Rad51p. If DNA ends were being resected, then the 3′-ended single-stranded regions ought to be attractive sites for the assembly of Rad51p filaments that is the first step in repairing DSBs by homologous recombination. However, no such foci containing both hMre11p and hRad51p were seen. A similar lack of colocalization has been seen in yeast cells that cannot complete meiosis and in irradiated mitotic cells (Usui et al. 1998xUsui, T, Ohta, T, Oshiumi, H, Tomizawa, J, Ogawa, H, and Ogawa, T. Cell. 1998; 95: 705–716Abstract | Full Text | Full Text PDF | PubMedSee all ReferencesUsui et al. 1998).The Mre11 complex is attracted to DSBs and can participate in several different pathways of repair and recombination. It remains “only” to figure out how Mre11p, Rad50p, Xrs2p, and the proteins with which they interact enable the cell to perform these many tasks. Given that almost half the papers on Mre11p have been published in 1998, it is likely we will soon learn much more about the many facets of this multitalented protein.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4b880f7557a70fdee5367fa85a3f47a6Test

المؤلفون: Franz Klein, Knud Nairz

المصدر: Genes & Development. 11:2272-2290

مصطلحات موضوعية: Saccharomyces cerevisiae Proteins, DNA Repair, DNA repair, genetic processes, Genes, Fungal, Molecular Sequence Data, Saccharomyces cerevisiae, Biology, Models, Biological, Fungal Proteins, Meiosis, Genetics, Homologous chromosome, Amino Acid Sequence, DNA, Fungal, Alleles, In Situ Hybridization, Fluorescence, DNA Primers, Recombination, Genetic, Endodeoxyribonucleases, Base Sequence, Sequence Homology, Amino Acid, Synaptonemal Complex, Genetic Complementation Test, fungi, Synapsis, Microscopy, Electron, enzymes and coenzymes (carbohydrates), Synaptonemal complex, Exodeoxyribonucleases, MRX complex, Rad50, Mutation, biological phenomena, cell phenomena, and immunity, Homologous recombination, Dimerization, DNA Damage, Research Paper, Developmental Biology

الوصف: During meiotic prophase the repair of self-inflicted DNA double-strand break (DSB) damage leads to meiotic recombination in yeast. We employed a genetic screen to specifically characterize cellular functions that become essential after this DSB formation. As a result a new allele of MRE11, termed mre11S (forSeparation of functions) was isolated that allows initiation but not processing and repair of meiotic DSBs similar to the well-characterized rad50S allele. In contrast, themre11-1 allele blocks initiation of meiotic DSBs as reported previously by others. The mre11S allele, which is mutated in the 5′ part of the gene, can partially complement mre11alleles disrupted close to the 3′ end that cannot initiate DSBs when homozygous. This suggests homodimerization of the Mre11 protein and the presence of separate domains for DSB initiation and 5′ resection. The fact that two genes, RAD50 and MRE11,required for DSB processing are also essential for DSB initiation dictates a model in which a bifunctional initiation/repair complex is required to initiate meiotic recombination. A subset of mre11S nuclei was shown to perform extensive but partially nonhomologous synapsis. We propose that the unprocessed DSBs present in mre11S allow for synapsis, but that homologous synapsis is only ensured at a later stage of recombination.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e0aa50d96e613e7a8b12516be301c8ffTest
https://doi.org/10.1101/gad.11.17.2272Test

المؤلفون: Michael Lisby, Iben Bach Bentsen, Helena B. Nielsen, Anni H. Andersen, Lotte Bjergbaek, Souvik Sen Gupta, Ida Kallehauge Nielsen, Kamilla Mundbjerg

المصدر: Bentsen, I B, Nielsen, I, Lisby, M, Nielsen, H B N, Sen Gupta, S, Mundbjerg, K, Andersen, A H & Bjergbæk, L 2013, ' MRX protects fork integrity at protein–DNA barriers, and its absence causes checkpoint activation dependent on chromatin context ', Nucleic Acids Research, vol. 41, no. 5, pp. 3173-3189 . https://doi.org/10.1093/nar/gkt051Test
Bentsen, I B, Nielsen, I, Lisby, M, Nielsen, H B, Sen Gupta, S, Mundbjerg, K, Andersen, A H & Bjergbaek, L 2013, ' MRX protects fork integrity at protein-DNA barriers, and its absence causes checkpoint activation dependent on chromatin context ', Nucleic Acids Research, vol. 41, no. 5, pp. 3173-3189 . https://doi.org/10.1093/nar/gkt051Test
Nucleic Acids Research

مصطلحات موضوعية: DNA Replication, Cell cycle checkpoint, Saccharomyces cerevisiae Proteins, Saccharomyces cerevisiae, DNA, Single-Stranded, Context (language use), Cell Cycle Proteins, Protein Serine-Threonine Kinases, Genome Integrity, Repair and Replication, DNA, Ribosomal, chemistry.chemical_compound, Sirtuin 2, Genetics, DNA, Fungal, Homologous Recombination, Silent Information Regulator Proteins, Saccharomyces cerevisiae, Endodeoxyribonucleases, biology, Cell Cycle Checkpoints, DNA Replication Fork, biology.organism_classification, Chromatin, Cell biology, DNA-Binding Proteins, Checkpoint Kinase 2, enzymes and coenzymes (carbohydrates), MRX complex, Exodeoxyribonucleases, chemistry, Rad50, DNA

الوصف: To address how eukaryotic replication forks respond to fork stalling caused by strong non-covalent protein–DNA barriers, we engineered the controllable Fob-block system in Saccharomyces cerevisiae. This system allows us to strongly induce and control replication fork barriers (RFB) at their natural location within the rDNA. We discover a pivotal role for the MRX (Mre11, Rad50, Xrs2) complex for fork integrity at RFBs, which differs from its acknowledged function in double-strand break processing. Consequently, in the absence of the MRX complex, single-stranded DNA (ssDNA) accumulates at the rDNA. Based on this, we propose a model where the MRX complex specifically protects stalled forks at protein–DNA barriers, and its absence leads to processing resulting in ssDNA. To our surprise, this ssDNA does not trigger a checkpoint response. Intriguingly, however, placing RFBs ectopically on chromosome VI provokes a strong Rad53 checkpoint activation in the absence of Mre11. We demonstrate that proper checkpoint signalling within the rDNA is restored on deletion of SIR2. This suggests the surprising and novel concept that chromatin is an important player in checkpoint signalling.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d124cc7fc3d39e876aad0ecc90865dfeTest
https://pure.au.dk/ws/files/53407175/Nucl._Acids_Res._2013_Bentsen_3173_89.pdfTest