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Tanasie NL, Gutiérrez-Escribano P, Jaklin S, Aragón L, Stigler J. Single molecule investigation reveals sursprising features of budding yeast SMC 5/6-DNA interactions. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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2
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Villoria MT, Gutiérrez-Escribano P, Alonso-Rodríguez E, Ramos F, Merino E, Campos A, Montoya A, Kramer H, Aragón L, Clemente-Blanco A. PP4 phosphatase cooperates in recombinational DNA repair by enhancing double-strand break end resection. Nucleic Acids Res 2020; 47:10706-10727. [PMID: 31544936 PMCID: PMC6846210 DOI: 10.1093/nar/gkz794] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 12/30/2022] Open
Abstract
The role of Rad53 in response to a DNA lesion is central for the accurate orchestration of the DNA damage response. Rad53 activation relies on its phosphorylation by Mec1 and its own autophosphorylation in a manner dependent on the adaptor Rad9. While the mechanism behind Rad53 activation has been well documented, less is known about the processes that counteract its activity along the repair of a DNA adduct. Here, we describe that PP4 phosphatase is required to avoid Rad53 hyper-phosphorylation during the repair of a double-strand break, a process that impacts on the phosphorylation status of multiple factors involved in the DNA damage response. PP4-dependent Rad53 dephosphorylation stimulates DNA end resection by relieving the negative effect that Rad9 exerts over the Sgs1/Dna2 exonuclease complex. Consequently, elimination of PP4 activity affects resection and repair by single-strand annealing, defects that are bypassed by reducing Rad53 hyperphosphorylation. These results confirm that Rad53 phosphorylation is controlled by PP4 during the repair of a DNA lesion and demonstrate that the attenuation of its kinase activity during the initial steps of the repair process is essential to efficiently enhance recombinational DNA repair pathways that depend on long-range resection for their success.
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Affiliation(s)
- María Teresa Villoria
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Pilar Gutiérrez-Escribano
- Cell Cycle Group. Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Facundo Ramos
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Eva Merino
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Adrián Campos
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Alex Montoya
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Luis Aragón
- Cell Cycle Group. Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
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3
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Bardell-Cox OA, White AJP, Aragón L, Fuchter MJ. Synthetic studies on the reverse antibiotic natural products, the nybomycins. Medchemcomm 2019; 10:1438-1444. [PMID: 31534658 PMCID: PMC6748283 DOI: 10.1039/c9md00207c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 05/22/2019] [Indexed: 11/21/2022]
Abstract
Antimicrobial resistance (AMR) is a serious issue that could have severe consequences if steps are not taken. The nybomycin natural products have the potential to extend the clinical efficacy of the marketed fluoroquinolone class of antibiotics through a 'reverse antibiotic' approach. However, only very limited structure-activity relationships are known for these fascinating compounds, in part due to challenges with their synthesis. Here we report a new scalable and robust synthetic route to the nybomycin natural products to aid in the development of this series. Through this synthesis, we report the antibiotic activity of novel analogues of this family confirming the selectivity for fluoroquinolone resistant bacteria and potential future opportunities for further optimisation.
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Affiliation(s)
- Oliver A Bardell-Cox
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub , White City Campus, Wood Lane , London , W12 OBZ , UK .
- Cell Cycle Group , MRC London Institute of Medical Sciences , Du Cane Road , London W12 0NN , UK .
| | - Andrew J P White
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub , White City Campus, Wood Lane , London , W12 OBZ , UK .
| | - Luis Aragón
- Cell Cycle Group , MRC London Institute of Medical Sciences , Du Cane Road , London W12 0NN , UK .
| | - Matthew J Fuchter
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub , White City Campus, Wood Lane , London , W12 OBZ , UK .
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Abstract
Smc5 and Smc6, together with the kleisin Nse4, form the heart of the enigmatic and poorly understood Smc5/6 complex, which is frequently viewed as a cousin of cohesin and condensin with functions in DNA repair. As novel functions for cohesin and condensin complexes in the organization of long-range chromatin architecture have recently emerged, new unsuspected roles for Smc5/6 have also surfaced. Here, I aim to provide a comprehensive overview of our current knowledge of the Smc5/6 complex, including its long-established function in genome stability, its multiple roles in DNA repair, and its recently discovered connection to the transcription inhibition of hepatitis B virus genomes. In addition, I summarize new research that is beginning to tease out the molecular details of Smc5/6 structure and function, knowledge that will illuminate the nuclear activities of Smc5/6 in the stability and dynamics of eukaryotic genomes.
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Affiliation(s)
- Luis Aragón
- Cell Cycle Group, MRC London Institute of Medical Sciences, Hammersmith Hospital Campus, London W12 0NN, United Kingdom;
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5
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Wong-Arteta J, Rey M, Aragón L, Gil E, Bujanda L. Comprehensive diagnosis of neoplastic effusions from the clinical laboratory. Clin Chim Acta 2019. [DOI: 10.1016/j.cca.2019.03.919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ramos F, Leonard J, Clemente-Blanco A, Aragón L. Cdc14 and Chromosome Condensation: Evaluation of the Recruitment of Condensin to Genomic Regions. Methods Mol Biol 2018; 1505:229-243. [PMID: 27826868 DOI: 10.1007/978-1-4939-6502-1_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Chromosome condensation is an essential morphological event required for successful DNA segregation during mitosis. The high level of genome compaction achieved during this process is attained by the evolutionary conserved condensin complex. Recently, several lines of evidences have demonstrated that the mitotic phosphatase Cdc14 is required to ensure condensin loading onto chromosomes. To date several approaches have been used in order to characterize condensin activity and regulation, however these techniques are time-consuming and require complex equipment. In this chapter we described an easy and reliable protocol to analyze Cdc14-dependent condensin loading onto specific genomic DNA regions by using a chromatin immunoprecipitation (ChIP) technique.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca (USAL), C/ Zacarías González 2, Salamanca, 37007, Spain
| | - Joanne Leonard
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca (USAL), C/ Zacarías González 2, Salamanca, 37007, Spain
| | - Luis Aragón
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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7
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Sen N, Leonard J, Torres R, Garcia-Luis J, Palou-Marin G, Aragón L. Physical Proximity of Sister Chromatids Promotes Top2-Dependent Intertwining. Mol Cell 2017; 64:134-147. [PMID: 27716481 PMCID: PMC5065527 DOI: 10.1016/j.molcel.2016.09.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 04/01/2016] [Accepted: 09/06/2016] [Indexed: 01/06/2023]
Abstract
Sister chromatid intertwines (SCIs), or catenanes, are topological links between replicated chromatids that interfere with chromosome segregation. The formation of SCIs is thought to be a consequence of fork swiveling during DNA replication, and their removal is thought to occur because of the intrinsic feature of type II topoisomerases (Top2) to simplify DNA topology. Here, we report that SCIs are also formed independently of DNA replication during G2/M by Top2-dependent concatenation of cohesed chromatids due to their physical proximity. We demonstrate that, in contrast to G2/M, Top2 removes SCIs from cohesed chromatids at the anaphase onset. Importantly, SCI removal in anaphase requires condensin and coincides with the hyperactivation of condensin DNA supercoiling activity. This is consistent with the longstanding proposal that condensin provides a bias in Top2 function toward decatenation. A comprehensive model for the formation and resolution of toxic SCI entanglements on eukaryotic genomes is proposed. Top2 introduces intertwining on chromatids independently of DNA replication Physical proximity between chromatids drives Top2 intertwining Sister chromatid intertwines are removed by Top2 at the anaphase onset Condensin DNA supercoiling activity correlates with Top2 intertwine removal
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Affiliation(s)
- Nicholas Sen
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Joanne Leonard
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Raul Torres
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Jonay Garcia-Luis
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Gloria Palou-Marin
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Luis Aragón
- MRC Clinical Sciences Centre (CSC), Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK.
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Ullal P, Vilella-Mitjana F, Jarmuz A, Aragón L. Retraction: Rtt107 Phosphorylation Promotes Localisation to DNA Double-Stranded Breaks (DSBs) and Recombinational Repair between Sister Chromatids. PLoS One 2017; 12:e0176035. [PMID: 28403246 PMCID: PMC5389852 DOI: 10.1371/journal.pone.0176035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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9
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Abstract
Cohesin is a protein complex with key roles in chromosome biology, from chromatid segregation to DNA repair. Cohesin function is regulated by several posttranslational modifications, including phosphorylation, acetylation, ubiquitylation, and SUMOylation. Recent studies have shown that cohesin SUMOylation is essential for sister chromatid cohesion during normal cell cycle and in response to DNA damage. Posttranslational modification by the small ubiquitin-like modifier (SUMO) is a field in expansion, however, detecting SUMOylation can be challenging because the amount of modified substrates are usually low and de-conjugation during sample preparation often occurs. In this chapter we describe a method that can be adapted to different model organisms, and substrates to detect SUMOylation. We focus on cohesin and show that SUMOylation indeed occurs in most of the subunits of budding yeast cohesin.
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Affiliation(s)
- Marcelino Bermúdez-López
- Cell Cycle Group, Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Luis Aragón
- Cell Cycle Group, Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
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Castiella A, Zapata E, De Juan MD, Zubiaurre L, Iribarren A, Otazua P, Fernandez J, Aragón L, Zuriarrain O, Gorostidi A. Analysis of HFE mutations and non-HFE gene mutations (TFR2 and SLC40A1) in patients with phenotypic hemochromatosis from the Basque Country. Int J Lab Hematol 2016; 38:e5-7. [PMID: 26547814 DOI: 10.1111/ijlh.12444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- A Castiella
- Gastroenterology Service, Mendaro Hospital, Mendaro, Spain.
| | - E Zapata
- Gastroenterology Service, Mendaro Hospital, Mendaro, Spain
| | - M D De Juan
- Immunology Service, Universitary Donostia Hospital, Donostia, Spain
| | - L Zubiaurre
- Gastroenterology Service, Mendaro Hospital, Mendaro, Spain
| | - A Iribarren
- Gastroenterology Service, Mendaro Hospital, Mendaro, Spain
| | - P Otazua
- Gastroenterology Service, Mondragon Hospital, Mondragon, Spain
| | - J Fernandez
- Gastroenterology Service, Galdakao Hospital, Galdakao, Spain
| | - L Aragón
- Immunology Service, Universitary Donostia Hospital, Donostia, Spain
| | - O Zuriarrain
- Genomics Platform, Biodonostia Institute, Donostia, Spain
| | - A Gorostidi
- Genomics Platform, Biodonostia Institute, Donostia, Spain
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11
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Leonard J, Sen N, Torres R, Sutani T, Jarmuz A, Shirahige K, Aragón L. Condensin Relocalization from Centromeres to Chromosome Arms Promotes Top2 Recruitment during Anaphase. Cell Rep 2015; 13:2336-2344. [PMID: 26686624 PMCID: PMC4695335 DOI: 10.1016/j.celrep.2015.11.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/08/2015] [Accepted: 11/11/2015] [Indexed: 11/29/2022] Open
Abstract
Condensin is a conserved chromosomal complex necessary to promote mitotic chromosome condensation and sister chromatid resolution during anaphase. Here, we report that yeast condensin binds to replicated centromere regions. We show that centromeric condensin relocalizes to chromosome arms as cells undergo anaphase segregation. We find that condensin relocalization is initiated immediately after the bipolar attachment of sister kinetochores to spindles and requires Polo kinase activity. Moreover, condensin localization during anaphase involves a higher binding rate on DNA and temporally overlaps with condensin’s DNA overwinding activity. Finally, we demonstrate that topoisomerase 2 (Top2) is also recruited to chromosome arms during anaphase in a condensin-dependent manner. Our results uncover a functional relation between condensin and Top2 during anaphase to mediate chromosome segregation. Condensin recruitment to centromeric regions requires DNA replication Centromeric condensin spreads to chromosome arms during anaphase Condensin promotes recruitment of Top2 during anaphase Condensin localization requires Polo kinase and correlates with DNA overwinding
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Affiliation(s)
- Joanne Leonard
- Cell Cycle Group, Medical Research Council (MRC), Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Nicholas Sen
- Cell Cycle Group, Medical Research Council (MRC), Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Raul Torres
- Cell Cycle Group, Medical Research Council (MRC), Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Takashi Sutani
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Adam Jarmuz
- Cell Cycle Group, Medical Research Council (MRC), Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Luis Aragón
- Cell Cycle Group, Medical Research Council (MRC), Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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12
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Torres-Rosell J, Machín F, Jarmuz A, Aragón L. Nucleolar Segregation Lags Behind the Rest of the Genome and Requires Cdc14p Activation by the FEAR Network. Cell Cycle 2014. [DOI: 10.4161/cc.3.4.802] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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13
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García-Luis J, Clemente-Blanco A, Aragón L, Machín F. Cdc14 targets the Holliday junction resolvase Yen1 to the nucleus in early anaphase. Cell Cycle 2014; 13:1392-9. [PMID: 24626187 DOI: 10.4161/cc.28370] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The only canonical Holliday junction (HJ) resolvase identified in eukaryotes thus far is Yen1/GEN1. Nevertheless, Yen1/GEN1 appears to have a minor role in HJ resolution, and, instead, other structure-specific endonucleases (SSE) that recognize branched DNA play the leading roles, Mus81-Mms4/EME1 being the most important in budding yeast. Interestingly, cells tightly regulate the activity of each HJ resolvase during the yeast cell cycle. Thus, Mus81-Mms4 is activated in G 2/M, while Yen1 gets activated shortly afterwards. Nevertheless, cytological studies have shown that Yen1 is sequestered out of the nucleus when cyclin-dependent kinase activity is high, i.e., all of the cell cycle but G 1. We here show that the mitotic master phosphatase Cdc14 targets Yen1 to the nucleus in early anaphase through the FEAR network. We will further show that this FEAR-mediated Cdc14-driven event is sufficient to back-up Mus81-Mms4 in removing branched DNA structures, which are especially found in the long chromosome arms upon replication stress. Finally, we found that MEN-driven Cdc14 re-activation in late anaphase is essential to keep Yen1 in the nucleus until the next G 1. Our results highlight the essential role that early-activated Cdc14, i.e., through the FEAR network, has in removing all kind of non-proteinaceous linkages that preclude faithful sister chromatid segregation in anaphase. In addition, our results support the general idea of Yen1 acting as a last resource endonuclease to deal with any remaining HJ that might compromise genetic stability during chromosome segregation.
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Affiliation(s)
- Jonay García-Luis
- Genomic Instability & Cancer Group; Unidad de Investigación; Hospital Universitario Nuestra Señora de Candelaria; Santa Cruz de Tenerife, Spain
| | | | - Luis Aragón
- Cell Cycle Group; MRC Clinical Sciences Centre; Imperial College London; London, UK
| | - Félix Machín
- Genomic Instability & Cancer Group; Unidad de Investigación; Hospital Universitario Nuestra Señora de Candelaria; Santa Cruz de Tenerife, Spain
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McAleenan A, Clemente-Blanco A, Cordon-Preciado V, Sen N, Esteras M, Jarmuz A, Aragón L. Post-replicative repair involves separase-dependent removal of the kleisin subunit of cohesin. Nature 2013; 493:250-4. [PMID: 23178808 DOI: 10.1038/nature11630] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 09/28/2012] [Indexed: 01/18/2023]
Abstract
DNA double-strand break repair is critical for cell viability and involves highly coordinated pathways to restore DNA integrity at the lesion. An early event during homology-dependent repair is resection of the break to generate progressively longer 3' single-strand tails that are used to identify suitable templates for repair. Sister chromatids provide near-perfect sequence homology and are therefore the preferred templates during homologous recombination. To provide a bias for the use of sisters as donors, cohesin--the complex that tethers sister chromatids together--is recruited to the break to enforce physical proximity. Here we show that DNA breaks promote dissociation of cohesin loaded during the previous S phase in budding yeast, and that damage-induced dissociation of cohesin requires separase, the protease that dissolves cohesion in anaphase. Moreover, a separase-resistant allele of the gene coding for the α-kleisin subunit of cohesin, Mcd1 (also known as Scc1), reduces double-strand break resection and compromises the efficiency of repair even when loaded during DNA damage. We conclude that post-replicative DNA repair involves cohesin dissociation by separase to promote accessibility to repair factors during the coordinated cellular response to restore DNA integrity.
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Affiliation(s)
- Alexandra McAleenan
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, Du Cane Road, London W12 0NN, UK
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15
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McAleenan A, Cordon-Preciado V, Clemente-Blanco A, Liu IC, Sen N, Leonard J, Jarmuz A, Aragón L. SUMOylation of the α-kleisin subunit of cohesin is required for DNA damage-induced cohesion. Curr Biol 2012; 22:1564-75. [PMID: 22771042 DOI: 10.1016/j.cub.2012.06.045] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/31/2012] [Accepted: 06/15/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cohesion between sister chromatids is fundamental to ensure faithful chromosome segregation during mitosis and accurate repair of DNA damage postreplication. At the molecular level, cohesion establishment involves two defined events, a chromatin binding step and a chromatid entrapment event driven by posttranslational modifications on cohesin subunits. RESULTS Here, we show that modification by the small ubiquitin-like protein (SUMO) is required for sister chromatid tethering after DNA damage. We find that all subunits of cohesin become SUMOylated upon exposure to DNA damaging agents or presence of a DNA double-strand break. We have mapped all lysine residues on cohesin's α-kleisin subunit Mcd1 (Scc1) where SUMO can conjugate. We demonstrate that Mcd1 SUMOylation-deficient alleles are still recruited to DSB-proximal regions but are defective in tethering sister chromatids and consequently fail to establish damage-induced cohesion both at DSBs and undamaged chromosomes. Moreover, we demonstrate that the bulk of Mcd1 SUMOylation in response to damage is carried out by the SUMO E3 ligase Nse2, a subunit of the related Smc5-Smc6 complex. SUMOylation occurs in cells with compromised Chk1 kinase activity, necessary for known posttranslational modifications on Mcd1, required for damage-induced cohesion. CONCLUSIONS These findings demonstrate that SUMOylation of Mcd1 is a novel prerequisite for the establishment of DNA damage-induced cohesion at DSB-proximal regions and cohesion-associating regions (CARs) genome-wide.
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Affiliation(s)
- Alexandra McAleenan
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, Du Cane Road, London W12 0NN, UK
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16
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Quevedo O, García-Luis J, Matos-Perdomo E, Aragón L, Machín F. Nondisjunction of a single chromosome leads to breakage and activation of DNA damage checkpoint in G2. PLoS Genet 2012; 8:e1002509. [PMID: 22363215 PMCID: PMC3280967 DOI: 10.1371/journal.pgen.1002509] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 12/08/2011] [Indexed: 11/18/2022] Open
Abstract
The resolution of chromosomes during anaphase is a key step in mitosis. Failure to disjoin chromatids compromises the fidelity of chromosome inheritance and generates aneuploidy and chromosome rearrangements, conditions linked to cancer development. Inactivation of topoisomerase II, condensin, or separase leads to gross chromosome nondisjunction. However, the fate of cells when one or a few chromosomes fail to separate has not been determined. Here, we describe a genetic system to induce mitotic progression in the presence of nondisjunction in yeast chromosome XII right arm (cXIIr), which allows the characterisation of the cellular fate of the progeny. Surprisingly, we find that the execution of karyokinesis and cytokinesis is timely and produces severing of cXIIr on or near the repetitive ribosomal gene array. Consequently, one end of the broken chromatid finishes up in each of the new daughter cells, generating a novel type of one-ended double-strand break. Importantly, both daughter cells enter a new cycle and the damage is not detected until the next G2, when cells arrest in a Rad9-dependent manner. Cytologically, we observed the accumulation of damage foci containing RPA/Rad52 proteins but failed to detect Mre11, indicating that cells attempt to repair both chromosome arms through a MRX-independent recombinational pathway. Finally, we analysed several surviving colonies arising after just one cell cycle with cXIIr nondisjunction. We found that aberrant forms of the chromosome were recovered, especially when RAD52 was deleted. Our results demonstrate that, in yeast cells, the Rad9-DNA damage checkpoint plays an important role responding to compromised genome integrity caused by mitotic nondisjunction.
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Affiliation(s)
- Oliver Quevedo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Jonay García-Luis
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Emiliano Matos-Perdomo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Luis Aragón
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
- * E-mail:
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17
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Ullal P, Vilella-Mitjana F, Jarmuz A, Aragón L. Rtt107 phosphorylation promotes localisation to DNA double-stranded breaks (DSBs) and recombinational repair between sister chromatids. PLoS One 2011; 6:e20152. [PMID: 21647453 PMCID: PMC3102082 DOI: 10.1371/journal.pone.0020152] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 04/19/2011] [Indexed: 01/16/2023] Open
Abstract
Efficient repair of DNA double-stranded breaks (DSB) requires a coordinated response at the site of lesion. Nucleolytic resection commits repair towards homologous recombination, which preferentially occurs between sister chromatids. DSB resection promotes recruitment of the Mec1 checkpoint kinase to the break. Rtt107 is a target of Mec1 and serves as a scaffold during repair. Rtt107 plays an important role during rescue of damaged replication forks, however whether Rtt107 contributes to the repair of DSBs is unknown. Here we show that Rtt107 is recruited to DSBs induced by the HO endonuclease. Rtt107 phosphorylation by Mec1 and its interaction with the Smc5–Smc6 complex are both required for Rtt107 loading to breaks, while Rtt107 regulators Slx4 and Rtt101 are not. We demonstrate that Rtt107 has an effect on the efficiency of sister chromatid recombination (SCR) and propose that its recruitment to DSBs, together with the Smc5–Smc6 complex is important for repair through the SCR pathway.
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Affiliation(s)
- Pranav Ullal
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College, London, United Kingdom
| | - Felipe Vilella-Mitjana
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College, London, United Kingdom
| | - Adam Jarmuz
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College, London, United Kingdom
| | - Luis Aragón
- Cell Cycle Group, Medical Research Council, Clinical Sciences Centre, Imperial College, London, United Kingdom
- * E-mail:
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18
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Baxter J, Sen N, Martínez VL, De Carandini MEM, Schvartzman JB, Diffley JFX, Aragón L. Positive supercoiling of mitotic DNA drives decatenation by topoisomerase II in eukaryotes. Science 2011; 331:1328-32. [PMID: 21393545 DOI: 10.1126/science.1201538] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
DNA topoisomerase II completely removes DNA intertwining, or catenation, between sister chromatids before they are segregated during cell division. How this occurs throughout the genome is poorly understood. We demonstrate that in yeast, centromeric plasmids undergo a dramatic change in their topology as the cells pass through mitosis. This change is characterized by positive supercoiling of the DNA and requires mitotic spindles and the condensin factor Smc2. When mitotic positive supercoiling occurs on decatenated DNA, it is rapidly relaxed by topoisomerase II. However, when positive supercoiling takes place in catenated plasmid, topoisomerase II activity is directed toward decatenation of the molecules before relaxation. Thus, a topological change on DNA drives topoisomerase II to decatenate molecules during mitosis, potentially driving the full decatenation of the genome.
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Affiliation(s)
- J Baxter
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London, UK.
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19
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Baxter J, Aragón L. Physical linkages between sister chromatids and their removal during yeast chromosome segregation. Cold Spring Harb Symp Quant Biol 2011; 75:389-94. [PMID: 21209386 DOI: 10.1101/sqb.2010.75.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The fidelity of chromosome inheritance is of paramount importance to all living organisms. In eukaryotic cells, the strategy to ensure physical segregation of chromosomes to daughter cells relies on two basic steps ordered in time: an initial linkage, or cohesion, of sister chromatids and its timely and complete dissolution during anaphase. The current view is that these two basic steps are accomplished around the regulation of a protein complex called cohesin that serves as "clamp brackets" distributed at intervals throughout the genome. However, many of the DNA metabolic activities during interphase also produce physical linking of chromatids. For example, during replication, intertwines between sister chromatids are formed. Here, we review our understanding of the processes that generate physical linkages between chromatids and discuss potential mechanisms that are involved in the removal of such obstacles to the complete physical separation of chromatids at anaphase.
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Affiliation(s)
- J Baxter
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, London W12 0NN, United Kingdom
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20
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Mayan M, Aragón L. Cis-interactions between non-coding ribosomal spacers dependent on RNAP-II separate RNAP-I and RNAP-III transcription domains. Cell Cycle 2010; 9:4328-37. [PMID: 20980822 DOI: 10.4161/cc.9.21.13591] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Ribosome biogenesis requires transcription of structural RNAs. In budding yeast, ribosomal units contain both 35S and 5S RNA genes separated by intergenic spacer sequences (IGS) that are transcribed by RNAP-II. IGS transcripts cause instability by promoting unequal sister chromatid recombination between repeats and are thus rapidly degraded by the exosome. Whether RNAP-II within IGS regions plays any functional role is unknown. Here we demonstrate that the bulk of RNAP-II bound to IGS sites is blocked for elongation and hence remains in a poised or stalled configuration. We describe a novel role for these stalled RNAP-II complexes in the formation of cis-interactions between the IGS of rDNA. We show that this function separates 35S and 5S RNA genes into polymerase-specific chromatin loops and demonstrate that removal of stalled RNAP-II complexes causes displacement of RNAP-III from the 5S gene region and transcriptional downregulation of 5S rRNA by spreading of RNAP-I. We conclude that stalled RNAP-II plays an active role in the cis-organisation of ribosomal repeats providing domains of polymerase specificity in the nucleolar transcription environment.
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Affiliation(s)
- María Mayan
- MRC Clinical Sciences Centre, Imperial College, London, UK
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21
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Abstract
The numbers of different types of ovarian follicles (developing, degenerating and postovulatory follicles) were estimated in bluefin tuna Thunnus thynnus using two stereological procedures: the model-based method of Weibel & Gomez, which has become a tool of broad application in the quantification of oocytes in fishes, and the assumption-free 'disector' (sic) method of Sterio. The estimates of developing follicles (follicles containing lipid-stage, vitellogenic and migratory-nucleus oocytes) made by the model-based method tended to be lower than those obtained with the disector, though significant differences were not observed except for vitellogenic follicles. Counts of atretic follicles by the model-based method were higher than those made using the disector, the differences being remarkable between both techniques, particularly in the case of beta-atresia, where the statistical analysis indicated significantly unequal estimations with the two methods. In contrast, the amount of postovulatory follicles estimated by the disector, which would stand for the realized batch fecundity, was somewhat larger than that calculated with the model-based method.
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Affiliation(s)
- L Aragón
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Avda. República Saharaui, s/n, E-11510, Puerto Real, Cádiz, Spain
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22
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Bermúdez-López M, Ceschia A, de Piccoli G, Colomina N, Pasero P, Aragón L, Torres-Rosell J. The Smc5/6 complex is required for dissolution of DNA-mediated sister chromatid linkages. Nucleic Acids Res 2010; 38:6502-12. [PMID: 20571088 PMCID: PMC2965248 DOI: 10.1093/nar/gkq546] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitotic chromosome segregation requires the removal of physical connections between sister chromatids. In addition to cohesin and topological entrapments, sister chromatid separation can be prevented by the presence of chromosome junctions or ongoing DNA replication. We will collectively refer to them as DNA-mediated linkages. Although this type of structures has been documented in different DNA replication and repair mutants, there is no known essential mechanism ensuring their timely removal before mitosis. Here, we show that the dissolution of these connections is an active process that requires the Smc5/6 complex, together with Mms21, its associated SUMO-ligase. Failure to remove DNA-mediated linkages causes gross chromosome missegregation in anaphase. Moreover, we show that Smc5/6 is capable to dissolve them in metaphase-arrested cells, thus restoring chromosome resolution and segregation. We propose that Smc5/6 has an essential role in the removal of DNA-mediated linkages to prevent chromosome missegregation and aneuploidy.
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Affiliation(s)
- Marcelino Bermúdez-López
- IRBLLEIDA, Department of Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, 25008 Lleida, Spain
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23
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24
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Conde F, Refolio E, Cordón-Preciado V, Cortés-Ledesma F, Aragón L, Aguilera A, San-Segundo PA. The Dot1 histone methyltransferase and the Rad9 checkpoint adaptor contribute to cohesin-dependent double-strand break repair by sister chromatid recombination in Saccharomyces cerevisiae. Genetics 2009; 182:437-46. [PMID: 19332880 PMCID: PMC2691753 DOI: 10.1534/genetics.109.101899] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 03/26/2009] [Indexed: 12/20/2022] Open
Abstract
Genomic integrity is threatened by multiple sources of DNA damage. DNA double-strand breaks (DSBs) are among the most dangerous types of DNA lesions and can be generated by endogenous or exogenous agents, but they can arise also during DNA replication. Sister chromatid recombination (SCR) is a key mechanism for the repair of DSBs generated during replication and it is fundamental for maintaining genomic stability. Proper repair relies on several factors, among which histone modifications play important roles in the response to DSBs. Here, we study the role of the histone H3K79 methyltransferase Dot1 in the repair by SCR of replication-dependent HO-induced DSBs, as a way to assess its function in homologous recombination. We show that Dot1, the Rad9 DNA damage checkpoint adaptor, and phosphorylation of histone H2A (gammaH2A) are required for efficient SCR. Moreover, we show that Dot1 and Rad9 promote DSB-induced loading of cohesin onto chromatin. We propose that recruitment of Rad9 to DSB sites mediated by gammaH2A and H3K79 methylation contributes to DSB repair via SCR by regulating cohesin binding to damage sites. Therefore, our results contribute to an understanding of how different chromatin modifications impinge on DNA repair mechanisms, which are fundamental for maintaining genomic stability.
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25
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Clemente-Blanco A, Mayán-Santos M, Schneider DA, Machín F, Jarmuz A, Tschochner H, Aragón L. Cdc14 inhibits transcription by RNA polymerase I during anaphase. Nature 2009; 458:219-22. [PMID: 19158678 DOI: 10.1038/nature07652] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 11/13/2008] [Indexed: 01/13/2023]
Abstract
Chromosome condensation and the global repression of gene transcription are features of mitosis in most eukaryotes. The logic behind this phenomenon is that chromosome condensation prevents the activity of RNA polymerases. In budding yeast, however, transcription was proposed to be continuous during mitosis. Here we show that Cdc14, a protein phosphatase required for nucleolar segregation and mitotic exit, inhibits transcription of yeast ribosomal genes (rDNA) during anaphase. The phosphatase activity of Cdc14 is required for RNA polymerase I (Pol I) inhibition in vitro and in vivo. Moreover Cdc14-dependent inhibition involves nucleolar exclusion of Pol I subunits. We demonstrate that transcription inhibition is necessary for complete chromosome disjunction, because ribosomal RNA (rRNA) transcripts block condensin binding to rDNA, and show that bypassing the role of Cdc14 in nucleolar segregation requires in vivo degradation of nascent transcripts. Our results show that transcription interferes with chromosome condensation, not the reverse. We conclude that budding yeast, like most eukaryotes, inhibit Pol I transcription before segregation as a prerequisite for chromosome condensation and faithful genome separation.
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Affiliation(s)
- Andrés Clemente-Blanco
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, Du Cane Road, London W12 0NN, UK
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26
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Abstract
The structural maintenance of chromosome (SMC) proteins constitute the cores of three protein complexes involved in chromosome metabolism; cohesin, condensin and the Smc5-Smc6 complex. While the roles of cohesin and condensin in sister chromatid cohesion and chromosome condensation respectively have been described, the cellular function of Smc5-Smc6 is as yet not understood, consequently the less descriptive name. The complex is involved in a variety of DNA repair pathways. It contains activities reminiscent of those described for cohesin and condensin, as well as several DNA helicases and endonucleases. It is required for sister chromatid recombination, and smc5-smc6 mutants suffer from the accumulation of unscheduled recombination intermediates. The complex contains a SUMO-ligase and potentially an ubiquitin-ligase; thus Smc5-Smc6 might presently have a dull name, but it seems destined to be recognized as a key player in the maintenance of chromosome stability. In this review we summarize our present understanding of this enigmatic protein complex.
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Affiliation(s)
- Giacomo De Piccoli
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, Du Cane Road, London W12 0NN, UK
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27
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Torres-Rosell J, Sunjevaric I, De Piccoli G, Sacher M, Eckert-Boulet N, Reid R, Jentsch S, Rothstein R, Aragón L, Lisby M. The Smc5-Smc6 complex and SUMO modification of Rad52 regulates recombinational repair at the ribosomal gene locus. Nat Cell Biol 2007; 9:923-31. [PMID: 17643116 DOI: 10.1038/ncb1619] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 06/28/2007] [Indexed: 01/25/2023]
Abstract
Homologous recombination (HR) is crucial for maintaining genome integrity by repairing DNA double-strand breaks (DSBs) and rescuing collapsed replication forks. In contrast, uncontrolled HR can lead to chromosome translocations, loss of heterozygosity, and deletion of repetitive sequences. Controlled HR is particularly important for the preservation of repetitive sequences of the ribosomal gene (rDNA) cluster. Here we show that recombinational repair of a DSB in rDNA in Saccharomyces cerevisiae involves the transient relocalization of the lesion to associate with the recombination machinery at an extranucleolar site. The nucleolar exclusion of Rad52 recombination foci entails Mre11 and Smc5-Smc6 complexes and depends on Rad52 SUMO (small ubiquitin-related modifier) modification. Remarkably, mutations that abrogate these activities result in the formation of Rad52 foci within the nucleolus and cause rDNA hyperrecombination and the excision of extrachromosomal rDNA circles. Our study also suggests a key role of sumoylation for nucleolar dynamics, perhaps in the compartmentalization of nuclear activities.
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Affiliation(s)
- Jordi Torres-Rosell
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
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28
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Abstract
Completion of DNA replication before mitosis is essential for genome stability and cell viability. Cellular controls called checkpoints act as surveillance mechanisms capable of detecting errors and blocking cell cycle progression to allow time for those errors to be corrected. An important question in the cell cycle field is whether eukaryotic cells possess mechanisms that monitor ongoing DNA replication and make sure that all chromosomes are fully replicated before entering mitosis, that is whether a replication-completion checkpoint exists. From recent studies with smc5–smc6 mutants it appears that yeast cells can enter anaphase without noticing that replication in the ribosomal DNA array was unfinished. smc5–smc6 mutants are proficient in all known cellular checkpoints, namely the S phase checkpoint, DNA-damage checkpoint, and spindle checkpoint, thus suggesting that none of these checkpoints can monitor the presence of unreplicated segments or the unhindered progression of forks in rDNA. Therefore, these results strongly suggest that normal yeast cells do not contain a DNA replication-completion checkpoint.
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Affiliation(s)
- Jordi Torres-Rosell
- Dept. Ciències Mèdiques Bàsiques, IRBLLEIDA, Universitat de Lleida, Montserrat Roig 2, 25008 Lleida, Spain
| | - Giacomo De Piccoli
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Luis Aragón
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
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29
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Abstract
Homologous recombination (HR) is one of the key mechanisms responsible for the repair of DNA double-strand breaks (DSBs), including those that occur during DNA replication. Recent studies in yeast and mammals have uncovered that the SMC complexes cohesins and Smc5-Smc6 are recruited to induced DSBs, and play a role in the maintenance of genome stability by favouring SCR as the main recombinational DSB repair mechanism. These new results raise intriguing questions such as whether SMC proteins might play a functional role at collapsed replication forks, which may represent the main source of spontaneous recombinogenic damage. A deeper knowledge of the role of SMC proteins in DSB repair should contribute to a better understanding of chromosome dynamics and stability.
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Affiliation(s)
- Felipe Cortés-Ledesma
- Department of Molecular Biology, CABIMER, CSIC-Universidad de Sevilla, Sevilla, Spain
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30
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Torres-Rosell J, De Piccoli G, Cordon-Preciado V, Farmer S, Jarmuz A, Machin F, Pasero P, Lisby M, Haber JE, Aragón L. Anaphase onset before complete DNA replication with intact checkpoint responses. Science 2007; 315:1411-5. [PMID: 17347440 DOI: 10.1126/science.1134025] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cellular checkpoints prevent mitosis in the presence of stalled replication forks. Whether checkpoints also ensure the completion of DNA replication before mitosis is unknown. Here, we show that in yeast smc5-smc6 mutants, which are related to cohesin and condensin, replication is delayed, most significantly at natural replication-impeding loci like the ribosomal DNA gene cluster. In the absence of Smc5-Smc6, chromosome nondisjunction occurs as a consequence of mitotic entry with unfinished replication despite intact checkpoint responses. Eliminating processes that obstruct replication fork progression restores the temporal uncoupling between replication and segregation in smc5-smc6 mutants. We propose that the completion of replication is not under the surveillance of known checkpoints.
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MESH Headings
- Anaphase
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Checkpoint Kinase 2
- Chromosome Segregation
- Chromosomes, Fungal/genetics
- Chromosomes, Fungal/metabolism
- DNA Breaks, Double-Stranded
- DNA Damage
- DNA Replication
- DNA, Fungal/genetics
- DNA, Fungal/metabolism
- DNA, Ribosomal/genetics
- DNA, Ribosomal/metabolism
- Genes, Fungal
- Genes, rRNA
- Metaphase
- Mitosis
- Models, Genetic
- Mutation
- Nondisjunction, Genetic
- Protein Serine-Threonine Kinases/metabolism
- S Phase
- Saccharomyces cerevisiae/cytology
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
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Affiliation(s)
- Jordi Torres-Rosell
- Cell Cycle Group, Medical Research Council (MRC) Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
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31
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De Piccoli G, Cortes-Ledesma F, Ira G, Torres-Rosell J, Uhle S, Farmer S, Hwang JY, Machin F, Ceschia A, McAleenan A, Cordon-Preciado V, Clemente-Blanco A, Vilella-Mitjana F, Ullal P, Jarmuz A, Leitao B, Bressan D, Dotiwala F, Papusha A, Zhao X, Myung K, Haber JE, Aguilera A, Aragón L. Smc5-Smc6 mediate DNA double-strand-break repair by promoting sister-chromatid recombination. Nat Cell Biol 2006; 8:1032-4. [PMID: 16892052 PMCID: PMC4493748 DOI: 10.1038/ncb1466] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Accepted: 07/14/2006] [Indexed: 02/06/2023]
Abstract
DNA double-strand breaks (DSB) can arise during DNA replication, or after exposure to DNA-damaging agents, and their correct repair is fundamental for cell survival and genomic stability. Here, we show that the Smc5-Smc6 complex is recruited to DSBs de novo to support their repair by homologous recombination between sister chromatids. In addition, we demonstrate that Smc5-Smc6 is necessary to suppress gross chromosomal rearrangements. Our findings show that the Smc5-Smc6 complex is essential for genome stability as it promotes repair of DSBs by error-free sister-chromatid recombination (SCR), thereby suppressing inappropriate non-sister recombination events.
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Affiliation(s)
- Giacomo De Piccoli
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Felipe Cortes-Ledesma
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Gregory Ira
- Rosenstiel Center, Brandeis University, 415 South St., Mail Stop 029, Waltham, MA 02454–9110, USA
- Baylor College of Medicine, Department of Human and Molecular Genetics, One Baylor Plaza, Houston, TX 77030, USA
| | - Jordi Torres-Rosell
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Stefan Uhle
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Sarah Farmer
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Ji-Young Hwang
- Genome Instability Section, Genetics & Molecular Biology Branch, National Human Genome Research Institute, NIH, 49 Convent Drive, Bethesda, MD 20892–4442, USA
| | - Felix Machin
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Audrey Ceschia
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Alexandra McAleenan
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Violeta Cordon-Preciado
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Andrés Clemente-Blanco
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Felip Vilella-Mitjana
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Pranav Ullal
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Adam Jarmuz
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Beatriz Leitao
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Debra Bressan
- Rosenstiel Center, Brandeis University, 415 South St., Mail Stop 029, Waltham, MA 02454–9110, USA
| | - Farokh Dotiwala
- Rosenstiel Center, Brandeis University, 415 South St., Mail Stop 029, Waltham, MA 02454–9110, USA
| | - Alma Papusha
- Baylor College of Medicine, Department of Human and Molecular Genetics, One Baylor Plaza, Houston, TX 77030, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
| | - Kyungjae Myung
- Genome Instability Section, Genetics & Molecular Biology Branch, National Human Genome Research Institute, NIH, 49 Convent Drive, Bethesda, MD 20892–4442, USA
| | - James E. Haber
- Rosenstiel Center, Brandeis University, 415 South St., Mail Stop 029, Waltham, MA 02454–9110, USA
- Correspondence should be addressed to J.E.H, A.A. or L.A. (; or )
| | - Andrés Aguilera
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain
- Correspondence should be addressed to J.E.H, A.A. or L.A. (; or )
| | - Luis Aragón
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
- Correspondence should be addressed to J.E.H, A.A. or L.A. (; or )
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32
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Abstract
Mitotic disjunction of the repetitive ribosomal DNA (rDNA) involves specialized segregation mechanisms dependent on the conserved phosphatase Cdc14. The reason behind this requirement is unknown. We show that rDNA segregation requires Cdc14 partly because of its physical length but most importantly because a fraction of ribosomal RNA (rRNA) genes are transcribed at very high rates. We show that cells cannot segregate rDNA without Cdc14 unless they undergo genetic rearrangements that reduce rDNA copy number. We then demonstrate that cells with normal length rDNA arrays can segregate rDNA in the absence of Cdc14 as long as rRNA genes are not transcribed. In addition, our study uncovers an unexpected role for the replication barrier protein Fob1 in rDNA segregation that is independent of Cdc14. These findings demonstrate that highly transcribed loci can cause chromosome nondisjunction.
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Affiliation(s)
- Felix Machín
- Cell Cycle Group, Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, England, UK
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33
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Clemente-Blanco A, González-Novo A, Machín F, Caballero-Lima D, Aragón L, Sánchez M, de Aldana CRV, Jiménez J, Correa-Bordes J. The Cdc14p phosphatase affects late cell-cycle events and morphogenesis inCandida albicans. J Cell Sci 2006; 119:1130-43. [PMID: 16507592 DOI: 10.1242/jcs.02820] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We have characterized the CDC14 gene, which encodes a dual-specificity protein phosphatase in Candida albicans, and demonstrated that its deletion results in defects in cell separation, mitotic exit and morphogenesis. The C. albicans cdc14Δ mutants formed large aggregates of cells that resembled those found in ace2-null strains. In cdc14Δ cells, expression of Ace2p target genes was reduced and Ace2p did not accumulate specifically in daughter nuclei. Taken together, these results imply that Cdc14p is required for the activation and daughter-specific nuclear accumulation of Ace2p. Consistent with a role in cell separation, Cdc14p was targeted to the septum region during the M-G1 transition in yeast-form cells. Interestingly, hypha-inducing signals abolished the translocation of Cdc14p to the division plate, and this regulation depended on the cyclin Hgc1p, since hgc1Δ mutants were able to accumulate Cdc14p in the septum region of the germ tubes. In addition to its role in cytokinesis, Cdc14p regulated mitotic exit, since synchronous cultures of cdc14Δ cells exhibited a severe delay in the destruction of the mitotic cyclin Clb2p. Finally, deletion of CDC14 resulted in decreased invasion of solid agar medium and impaired true hyphal growth.
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Affiliation(s)
- Andrés Clemente-Blanco
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Extremadura, Avda Elvas SN, 06071, Badajoz, Spain
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Abstract
As a baton in a relay race, intact genomes need to be smoothly passed onto daughter cells every cell generation. Cohesin and condensin are multiprotein complexes involved in chromosome segregation during mitosis, they perform the crucial function of organizing and compacting chromosomes into pairs to facilitate their equal distribution in anaphase. Both complexes share a core of similar origin, containing a heterodimer formed by members of the conserved chromosomal ATPase family named Smc. A third complex containing Smc proteins at its core, the Smc5-Smc6 complex, previously known to be involved in DNA repair has recently been shown to contribute to chromosome segregation during anaphase. Smc5-Smc6 plays a role in the disjunction of repetitive regions. Here, we present results further supporting the importance of Smc5-Smc6 in maintaining the integrity of the repetitive ribosomal DNA (rDNA) locus, the largest repetitive region of the budding yeast genome.
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Affiliation(s)
- Jordi Torres-Rosell
- Medical Research Council, Clinical Sciences Centre, Imperial College London, London, UK
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Abstract
Mitotic cell division involves the equal segregation of all chromosomes during anaphase. The presence of ribosomal DNA (rDNA) repeats on the right arm of chromosome XII makes it the longest in the budding yeast genome. Previously, we identified a stage during yeast anaphase when rDNA is stretched across the mother and daughter cells. Here, we show that resolution of sister rDNAs is achieved by unzipping of the locus from its centromere-proximal to centromere-distal regions. We then demonstrate that during this stretched stage sister rDNA arrays are neither compacted nor segregated despite being largely resolved from each other. Surprisingly, we find that rDNA segregation after this period no longer requires spindles but instead involves Cdc14-dependent rDNA axial compaction. These results demonstrate that chromosome resolution is not simply a consequence of compacting chromosome arms and that overall rDNA compaction is necessary to mediate the segregation of the long arm of chromosome XII.
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Affiliation(s)
- Félix Machín
- Cell Cycle Group, Clinical Sciences Centre, Medical Research Council, Imperial College London, London W12 0NN, England, UK
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Torres-Rosell J, Machín F, Farmer S, Jarmuz A, Eydmann T, Dalgaard JZ, Aragón L. SMC5 and SMC6 genes are required for the segregation of repetitive chromosome regions. Nat Cell Biol 2005; 7:412-9. [PMID: 15793567 DOI: 10.1038/ncb1239] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Accepted: 02/17/2005] [Indexed: 11/08/2022]
Abstract
Structure chromosome (SMC) proteins organize the core of cohesin, condensin and Smc5-Smc6 complexes. The Smc5-Smc6 complex is required for DNA repair, as well as having another essential but enigmatic function. Here, we generated conditional mutants of SMC5 and SMC6 in budding yeast, in which the essential function was affected. We show that mutant smc5-6 and smc6-9 cells undergo an aberrant mitosis in which chromosome segregation of repetitive regions is impaired; this leads to DNA damage and RAD9-dependent activation of the Rad53 protein kinase. Consistent with a requirement for the segregation of repetitive regions, Smc5 and Smc6 proteins are enriched at ribosomal DNA (rDNA) and at some telomeres. We show that, following Smc5-Smc6 inactivation, metaphase-arrested cells show increased levels of X-shaped DNA (Holliday junctions) at the rDNA locus. Furthermore, deletion of RAD52 partially suppresses the temperature sensitivity of smc5-6 and smc6-9 mutants. We also present evidence showing that the rDNA segregation defects of smc5/smc6 mutants are mechanistically different from those previously observed for condensin mutants. These results point towards a role for the Smc5-Smc6 complex in preventing the formation of sister chromatid junctions, thereby ensuring the correct partitioning of chromosomes during anaphase.
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Affiliation(s)
- Jordi Torres-Rosell
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
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37
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Affiliation(s)
- Luis Aragón
- Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK.
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Abstract
Cell division involves the inheritance of a complete set of the genome in the form of chromosomes. One of the strategies employed by eukaryotic cells is to maintain replicated sister chromatids together until the anaphase onset. A protein complex named cohesin holds sisters together following replication until anaphase when cleavage of cohesin by the protease separase initiates segregation. Recent studies in budding yeast have shown that cohesin cleavage alone is not sufficient for the segregation of the entire genome. Instead, repetitive regions, such as the ribosomal DNA (rDNA) array and telomeres, require additional mechanisms during mitotic disjunction. The segregation of such chromosome regions is delayed and needs specific cell cycle regulators such as the FEAR network and the conserved phosphatase Cdc14, all of which orchestrate the timely completion of chromosome segregation before mitotic exit. Future studies will be targeted towards unravelling the nature of the additional segregation requirements for repetitive regions and the specifics of its cell cycle control.
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Affiliation(s)
- Jordi Torres-Rosell
- Cell Cycle Group, Clinical Sciences Centre, Medical Research Council, Imperial College London, London, UK
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Torres-Rosell J, Machín F, Jarmuz A, Aragón L. Nucleolar segregation lags behind the rest of the genome and requires Cdc14p activation by the FEAR network. Cell Cycle 2004; 3:496-502. [PMID: 15004526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
In order to transmit a full genetic complement cells must ensure that all chromosomes are accurately split and distributed during anaphase. Chromosome XII in S. cerevisiae contains the site of nucleolar assembly, a 1-2Mb array of rDNA genes named RDN1. Cdc14p is a conserved phosphatase, essential for anaphase progression and mitotic exit, which is kept inactive at the nucleolus until mitosis. In early anaphase, the FEAR network (Cdc Fourteen Early Anaphase Release) promotes the transient and partial release of Cdc14p from the nucleolus. The putative role of Cdc14p released by the FEAR network is thought to be the stimulation of full Cdc14p release by activation of the GTPase-driven signaling cascade (the Mitotic Exit Network or MEN) that ensures mitotic exit. Here, we show that nucleolar segregation is spatially separated and temporally delayed from the rest of the genome. Nucleolar segregation occurs during mid-anaphase and coincides with the FEAR release of Cdc14p. Inactivation of FEAR delays nucleolar segregation until late anaphase, demonstrating that one function of the FEAR network is to promote segregation of repetitive nucleolar chromatin during mid-anaphase.
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Affiliation(s)
- Jordi Torres-Rosell
- Cell Cycle Group, Clinical Sciences Center, Medical Research Council, Imperial College London, London, UK
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Machín F, Paschos K, Jarmuz A, Torres-Rosell J, Pade C, Aragón L. Condensin regulates rDNA silencing by modulating nucleolar Sir2p. Curr Biol 2004; 14:125-30. [PMID: 14738734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
The tandem array of ribosomal DNA (rDNA) in Saccharomyces cerevisiae is subjected to transcriptional silencing of RNA polymerase II-transcribed genes. This form of silencing depends on SIR2 and has been tightly linked to the suppression of rDNA recombination and the control of cellular lifespan. Paradoxically, rDNA silencing takes place in the context of an extremely high rate of RNA polymerase I transcription. Because rDNA silencing requires different factors than HMR and telomere silencing, the chromatin structure and the mechanisms of silencing must be fundamentally different. Here we show that yeast condensin organizes the specialized topology of rDNA chromatin. We then demonstrate that this function is necessary for maintaining the correct balance of telomeric and nucleolar Sir2p. Condensin mutants relocalize telomeric Sir2p to rDNA and show histone hyperacetylation at telomeres. Our data reveal the implication of yeast condensin in the arrangement of rDNA repeats into a heterochromatic-like structure that is important for the correct delineation of silencing domains in the nucleus.
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Affiliation(s)
- Felix Machín
- Cell Cycle Group, Medical Research Council Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
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Lafita J, Aragón L, Berraondo C, Díez J, García del Río JA, Rodríguez C, San Juan C, Ulibarri J. [Continuous quality improvement in the control of the type2 diabetes in Navarra. GEDAPSNA study 1996]. An Sist Sanit Navar 1999; 22:59-70. [PMID: 12886361 DOI: 10.23938/assn.0694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Diabetes mellitus type 2 constitutes one of the principal public health problems today, representing an important burden on care and involving extremely high economic costs, both direct and indirect. To provide an adequate response from the different public health systems, the St. Vincent Declaration was drawn up containing certain recommendations on the protocol of care and the carrying out of controls of continuous quality improvement, since it is a chronic pathology that requires a proactive health policy, which prevents, and provides early detection of its complications. In the present work we set out the results of the first study carried out in Navarra on the indicators of quality in the care provided to diabetics in Primary Health care, carried out by the Study Group on Diabetes Mellitus in Primary Care (GEDAPSNA). The study was made of an aleatory sample of 496 patients, by means of gathering data about their clinical records for the year 1996. 12 process indicators and 12 indicators of intermediate and final results were used. The results detect some important deficiencies that require early intervention: lack of exploration and management of the lesions that make up so-called diabetic foot; low achievement of results in the control of arterial hypertension in this group of patients; and absence of exploration of the lesions of the fundus of the eye in more than 50% of type 2 diabetics.
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Affiliation(s)
- J Lafita
- Servicio Endocrino, Centro de Consultas, Príncipe de Viana, Pamplona
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