1
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Meyer D, Ceballos SJ, Gore S, Liu J, Reginato G, Cano-Linares MI, Maslowska KH, Villafañez F, Ede C, Pagès V, Prado F, Cejka P, Heyer WD. Rad51 determines pathway usage in post-replication repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.599120. [PMID: 38915629 PMCID: PMC11195247 DOI: 10.1101/2024.06.14.599120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Stalled replication forks can be processed by several distinct mechanisms collectively called post-replication repair which includes homologous recombination, fork regression, and translesion DNA synthesis. However, the regulation of the usage between these pathways is not fully understood. The Rad51 protein plays a pivotal role in maintaining genomic stability through its roles in HR and in protecting stalled replication forks from degradation. We report the isolation of separation-of-function mutations in Saccharomyces cerevisiae Rad51 that retain their recombination function but display a defect in fork protection leading to a shift in post-replication repair pathway usage from HR to alternate pathways including mutagenic translesion synthesis. Rad51-E135D and Rad51-K305N show normal in vivo and in vitro recombination despite changes in their DNA binding profiles, in particular to dsDNA, with a resulting effect on their ATPase activities. The mutants lead to a defect in Rad51 recruitment to stalled forks in vivo as well as a defect in the protection of dsDNA from degradation by Dna2-Sgs1 and Exo1 in vitro . A high-resolution cryo-electron microscopy structure of the Rad51-ssDNA filament at 2.4 Å resolution provides a structural basis for a mechanistic understanding of the mutant phenotypes. Together, the evidence suggests a model in which Rad51 binding to duplex DNA is critical to control pathway usage at stalled replication forks.
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2
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Papp D, Hernandez LA, Mai TA, Haanen TJ, O’Donnell MA, Duran AT, Hernandez SM, Narvanto JE, Arguello B, Onwukwe MO, Mirkin SM, Kim JC. Massive contractions of myotonic dystrophy type 2-associated CCTG tetranucleotide repeats occur via double-strand break repair with distinct requirements for DNA helicases. G3 (BETHESDA, MD.) 2024; 14:jkad257. [PMID: 37950892 PMCID: PMC10849350 DOI: 10.1093/g3journal/jkad257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/06/2023] [Accepted: 10/19/2023] [Indexed: 11/13/2023]
Abstract
Myotonic dystrophy type 2 (DM2) is a genetic disease caused by expanded CCTG DNA repeats in the first intron of CNBP. The number of CCTG repeats in DM2 patients ranges from 75 to 11,000, yet little is known about the molecular mechanisms responsible for repeat expansions or contractions. We developed an experimental system in Saccharomyces cerevisiae that enables the selection of large-scale contractions of (CCTG)100 within the intron of a reporter gene and subsequent genetic analysis. Contractions exceeded 80 repeat units, causing the final repetitive tract to be well below the threshold for disease. We found that Rad51 and Rad52 are involved in these massive contractions, indicating a mechanism that uses homologous recombination. Srs2 helicase was shown previously to stabilize CTG, CAG, and CGG repeats. Loss of Srs2 did not significantly affect CCTG contraction rates in unperturbed conditions. In contrast, loss of the RecQ helicase Sgs1 resulted in a 6-fold decrease in contraction rate with specific evidence that helicase activity is required for large-scale contractions. Using a genetic assay to evaluate chromosome arm loss, we determined that CCTG and reverse complementary CAGG repeats elevate the rate of chromosomal fragility compared to a short-track control. Overall, our results demonstrate that the genetic control of CCTG repeat contractions is notably distinct among disease-causing microsatellite repeat sequences.
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Affiliation(s)
- David Papp
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Luis A Hernandez
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Theresa A Mai
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Terrance J Haanen
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Meghan A O’Donnell
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Ariel T Duran
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Sophia M Hernandez
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Jenni E Narvanto
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Berenice Arguello
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Marvin O Onwukwe
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Jane C Kim
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078, USA
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3
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Williams SL, Casas‐Delucchi CS, Raguseo F, Guneri D, Li Y, Minamino M, Fletcher EE, Yeeles JTP, Keyser UF, Waller ZAE, Di Antonio M, Coster G. Replication-induced DNA secondary structures drive fork uncoupling and breakage. EMBO J 2023; 42:e114334. [PMID: 37781931 PMCID: PMC10646557 DOI: 10.15252/embj.2023114334] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023] Open
Abstract
Sequences that form DNA secondary structures, such as G-quadruplexes (G4s) and intercalated-Motifs (iMs), are abundant in the human genome and play various physiological roles. However, they can also interfere with replication and threaten genome stability. Multiple lines of evidence suggest G4s inhibit replication, but the underlying mechanism remains unclear. Moreover, evidence of how iMs affect the replisome is lacking. Here, we reconstitute replication of physiologically derived structure-forming sequences to find that a single G4 or iM arrest DNA replication. Direct single-molecule structure detection within solid-state nanopores reveals structures form as a consequence of replication. Combined genetic and biophysical characterisation establishes that structure stability and probability of structure formation are key determinants of replisome arrest. Mechanistically, replication arrest is caused by impaired synthesis, resulting in helicase-polymerase uncoupling. Significantly, iMs also induce breakage of nascent DNA. Finally, stalled forks are only rescued by a specialised helicase, Pif1, but not Rrm3, Sgs1, Chl1 or Hrq1. Altogether, we provide a mechanism for quadruplex structure formation and resolution during replication and highlight G4s and iMs as endogenous sources of replication stress.
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Affiliation(s)
- Sophie L Williams
- Genome Replication Lab, Division of Cancer Biology, Institute of Cancer ResearchChester Beatty LaboratoriesLondonUK
| | - Corella S Casas‐Delucchi
- Genome Replication Lab, Division of Cancer Biology, Institute of Cancer ResearchChester Beatty LaboratoriesLondonUK
| | - Federica Raguseo
- Chemistry DepartmentImperial College London, MSRHLondonUK
- Institute of Chemical Biology, MSRHLondonUK
| | | | - Yunxuan Li
- Cavendish LaboratoryUniversity of CambridgeCambridgeUK
| | | | | | | | | | | | - Marco Di Antonio
- Chemistry DepartmentImperial College London, MSRHLondonUK
- Institute of Chemical Biology, MSRHLondonUK
- Francis Crick InstituteLondonUK
| | - Gideon Coster
- Genome Replication Lab, Division of Cancer Biology, Institute of Cancer ResearchChester Beatty LaboratoriesLondonUK
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4
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Papp D, Hernandez LA, Mai TA, Haanen TJ, O’Donnell MA, Duran AT, Hernandez SM, Narvanto JE, Arguello B, Onwukwe MO, Kolar K, Mirkin SM, Kim JC. Massive contractions of Myotonic Dystrophy Type 2-associated CCTG tetranucleotide repeats occur via double strand break repair with distinct requirements for helicases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.548036. [PMID: 37461657 PMCID: PMC10350092 DOI: 10.1101/2023.07.06.548036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Myotonic Dystrophy Type 2 (DM2) is a genetic disease caused by expanded CCTG DNA repeats in the first intron of CNBP. The number of CCTG repeats in DM2 patients ranges from 75-11,000, yet little is known about the molecular mechanisms responsible for repeat expansions or contractions. We developed an experimental system in Saccharomyces cerevisiae that enables selection of large-scale contractions of (CCTG)100 within the intron of a reporter gene and subsequent genetic analysis. Contractions exceeded 80 repeat units, causing the final repetitive tract to be well below the threshold for disease. We found that Rad51 and Rad52 are required for these massive contractions, indicating a mechanism that involves homologous recombination. Srs2 helicase was shown previously to stabilize CTG, CAG, and CGG repeats. Loss of Srs2 did not significantly affect CCTG contraction rates in unperturbed conditions. In contrast, loss of the RecQ helicase Sgs1 resulted in a 6-fold decrease in contraction rate with specific evidence that helicase activity is required for large-scale contractions. Using a genetic assay to evaluate chromosome arm loss, we determined that CCTG and reverse complementary CAGG repeats elevate the rate of chromosomal fragility compared to a low-repeat control. Overall, our results demonstrate that the genetic control of CCTG repeat contractions is notably distinct among disease-causing microsatellite repeat sequences.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Kara Kolar
- Department of Biology, Tufts University, Medford, MA 02155
| | | | - Jane C. Kim
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92078
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5
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Mengoli V, Ceppi I, Sanchez A, Cannavo E, Halder S, Scaglione S, Gaillard P, McHugh PJ, Riesen N, Pettazzoni P, Cejka P. WRN helicase and mismatch repair complexes independently and synergistically disrupt cruciform DNA structures. EMBO J 2023; 42:e111998. [PMID: 36541070 PMCID: PMC9890227 DOI: 10.15252/embj.2022111998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/07/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
The Werner Syndrome helicase, WRN, is a promising therapeutic target in cancers with microsatellite instability (MSI). Long-term MSI leads to the expansion of TA nucleotide repeats proposed to form cruciform DNA structures, which in turn cause DNA breaks and cell lethality upon WRN downregulation. Here we employed biochemical assays to show that WRN helicase can efficiently and directly unfold cruciform structures, thereby preventing their cleavage by the SLX1-SLX4 structure-specific endonuclease. TA repeats are particularly prone to form cruciform structures, explaining why these DNA sequences are preferentially broken in MSI cells upon WRN downregulation. We further demonstrate that the activity of the DNA mismatch repair (MMR) complexes MutSα (MSH2-MSH6), MutSβ (MSH2-MSH3), and MutLα (MLH1-PMS2) similarly decreases the level of DNA cruciforms, although the mechanism is different from that employed by WRN. When combined, WRN and MutLα exhibited higher than additive effects in in vitro cruciform processing, suggesting that WRN and the MMR proteins may cooperate. Our data explain how WRN and MMR defects cause genome instability in MSI cells with expanded TA repeats, and provide a mechanistic basis for their recently discovered synthetic-lethal interaction with promising applications in precision cancer therapy.
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Affiliation(s)
- Valentina Mengoli
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Ilaria Ceppi
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Aurore Sanchez
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Elda Cannavo
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Swagata Halder
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Sarah Scaglione
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix‐Marseille Université, Institut Paoli‐CalmettesMarseilleFrance
| | - Pierre‐Henri Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix‐Marseille Université, Institut Paoli‐CalmettesMarseilleFrance
| | - Peter J McHugh
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Nathalie Riesen
- Roche Pharma Research & Early Development pREDRoche Innovation CenterBaselSwitzerland
| | | | - Petr Cejka
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
- Department of Biology, Institute of BiochemistryEidgenössische Technische Hochschule (ETH)ZürichSwitzerland
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6
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Ceppi I, Cannavo E, Bret H, Camarillo R, Vivalda F, Thakur RS, Romero-Franco A, Sartori AA, Huertas P, Guérois R, Cejka P. PLK1 regulates CtIP and DNA2 interplay in long-range DNA end resection. Genes Dev 2023; 37:119-135. [PMID: 36746606 PMCID: PMC10069449 DOI: 10.1101/gad.349981.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 01/12/2023] [Indexed: 02/08/2023]
Abstract
DNA double-strand break (DSB) repair is initiated by DNA end resection. CtIP acts in short-range resection to stimulate MRE11-RAD50-NBS1 (MRN) to endonucleolytically cleave 5'-terminated DNA to bypass protein blocks. CtIP also promotes the DNA2 helicase-nuclease to accelerate long-range resection downstream from MRN. Here, using AlphaFold2, we identified CtIP-F728E-Y736E as a separation-of-function mutant that is still proficient in conjunction with MRN but is not able to stimulate ssDNA degradation by DNA2. Accordingly, CtIP-F728E-Y736E impairs physical interaction with DNA2. Cellular assays revealed that CtIP-F728E-Y736E cells exhibit reduced DSB-dependent chromatin-bound RPA, impaired long-range resection, and increased sensitivity to DSB-inducing drugs. Previously, CtIP was shown to be targeted by PLK1 to inhibit long-range resection, yet the underlying mechanism was unclear. We show that the DNA2-interacting region in CtIP includes the PLK1 target site at S723. The integrity of S723 in CtIP is necessary for the stimulation of DNA2, and phosphorylation of CtIP by PLK1 in vitro is consequently inhibitory, explaining why PLK1 restricts long-range resection. Our data support a model in which CDK-dependent phosphorylation of CtIP activates resection by MRN in S phase, and PLK1-mediated phosphorylation of CtIP disrupts CtIP stimulation of DNA2 to attenuate long-range resection later at G2/M.
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Affiliation(s)
- Ilaria Ceppi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona 6500, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| | - Elda Cannavo
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona 6500, Switzerland
| | - Hélène Bret
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91190, France
| | - Rosa Camarillo
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla 41080, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Francesca Vivalda
- Institute of Molecular Cancer Research, University of Zürich, Zürich 8057, Switzerland
| | - Roshan Singh Thakur
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona 6500, Switzerland
| | - Amador Romero-Franco
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla 41080, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Alessandro A Sartori
- Institute of Molecular Cancer Research, University of Zürich, Zürich 8057, Switzerland
| | - Pablo Huertas
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla 41080, Spain
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Raphaël Guérois
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91190, France
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona 6500, Switzerland;
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
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7
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Halder S, Sanchez A, Ranjha L, Reginato G, Ceppi I, Acharya A, Anand R, Cejka P. Double-stranded DNA binding function of RAD51 in DNA protection and its regulation by BRCA2. Mol Cell 2022; 82:3553-3565.e5. [PMID: 36070766 DOI: 10.1016/j.molcel.2022.08.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/16/2022] [Accepted: 08/10/2022] [Indexed: 11/26/2022]
Abstract
RAD51 and the breast cancer suppressor BRCA2 have critical functions in DNA double-strand (dsDNA) break repair by homologous recombination and the protection of newly replicated DNA from nucleolytic degradation. The recombination function of RAD51 requires its binding to single-stranded DNA (ssDNA), whereas binding to dsDNA is inhibitory. Using reconstituted MRE11-, EXO1-, and DNA2-dependent nuclease reactions, we show that the protective function of RAD51 unexpectedly depends on its binding to dsDNA. The BRC4 repeat of BRCA2 abrogates RAD51 binding to dsDNA and accordingly impairs the function of RAD51 in protection. The BRCA2 C-terminal RAD51-binding segment (TR2) acts in a dominant manner to overcome the effect of BRC4. Mechanistically, TR2 stabilizes RAD51 binding to dsDNA, even in the presence of BRC4, promoting DNA protection. Our data suggest that RAD51's dsDNA-binding capacity may have evolved together with its function in replication fork protection and provide a mechanistic basis for the DNA-protection function of BRCA2.
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Affiliation(s)
- Swagata Halder
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland
| | - Aurore Sanchez
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland
| | - Lepakshi Ranjha
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland
| | - Giordano Reginato
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8049 Zürich, Switzerland
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8049 Zürich, Switzerland
| | - Ananya Acharya
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8049 Zürich, Switzerland
| | - Roopesh Anand
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8049 Zürich, Switzerland.
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8
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Nickens DG, Bochman ML. Genetic and biochemical interactions of yeast DNA helicases. Methods 2022; 204:234-240. [PMID: 35483549 DOI: 10.1016/j.ymeth.2022.04.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 12/13/2022] Open
Abstract
DNA helicases function in many types of nucleic acid transactions, and as such, they are vital for genome integrity. Although they are often considered individually, work from many groups demonstrates that these enzymes often genetically and biochemically interact in vivo. Here, we highlight methods to interrogate such interactions among the PIF1 (Pif1 and Rrm3) and RecQ (Hrq1 and Sgs1) family helicases in Saccharomyces cerevisiae. The interactions among these enzymes were investigated in vivo using deletion and inactivation alleles with a gross-chromosomal rearrangement (GCR) assay. Further, wild-type and inactive recombinant proteins were used to determine the effects of the helicases on telomerase activity in vitro. We found that synergistic increases in GCR rates often occur in double vs. single mutants, suggesting that the helicases function in distinct genome integrity pathways. Further, the recombinant helicases can function together in vitro to modulate telomerase activity. Overall, the data suggest that the interactions among the members of these DNA helicase families are multipartite and argue for a comprehensive systems biology approach to fully elucidate the physiological interplay between these enzymes.
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Affiliation(s)
- David G Nickens
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405 USA
| | - Matthew L Bochman
- Molecular & Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405 USA.
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9
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A POLD3/BLM dependent pathway handles DSBs in transcribed chromatin upon excessive RNA:DNA hybrid accumulation. Nat Commun 2022; 13:2012. [PMID: 35440629 PMCID: PMC9019021 DOI: 10.1038/s41467-022-29629-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 03/25/2022] [Indexed: 12/03/2022] Open
Abstract
Transcriptionally active loci are particularly prone to breakage and mounting evidence suggests that DNA Double-Strand Breaks arising in active genes are handled by a dedicated repair pathway, Transcription-Coupled DSB Repair (TC-DSBR), that entails R-loop accumulation and dissolution. Here, we uncover a function for the Bloom RecQ DNA helicase (BLM) in TC-DSBR in human cells. BLM is recruited in a transcription dependent-manner at DSBs where it fosters resection, RAD51 binding and accurate Homologous Recombination repair. However, in an R-loop dissolution-deficient background, we find that BLM promotes cell death. We report that upon excessive RNA:DNA hybrid accumulation, DNA synthesis is enhanced at DSBs, in a manner that depends on BLM and POLD3. Altogether our work unveils a role for BLM at DSBs in active chromatin, and highlights the toxic potential of RNA:DNA hybrids that accumulate at transcription-associated DSBs. DNA Double Strand breaks in transcriptionally active loci (TC-DSBs) undergo a dedicated repair pathway. Here, the authors show that excessive RNA:DNA hybrid accumulation at TC-DSBs elicits POLD3/BLM-dependent DNA synthesis that induces cell toxicity.
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10
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Distinct RPA domains promote recruitment and the helicase-nuclease activities of Dna2. Nat Commun 2021; 12:6521. [PMID: 34764291 PMCID: PMC8586334 DOI: 10.1038/s41467-021-26863-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/21/2021] [Indexed: 01/25/2023] Open
Abstract
The Dna2 helicase-nuclease functions in concert with the replication protein A (RPA) in DNA double-strand break repair. Using ensemble and single-molecule biochemistry, coupled with structure modeling, we demonstrate that the stimulation of S. cerevisiae Dna2 by RPA is not a simple consequence of Dna2 recruitment to single-stranded DNA. The large RPA subunit Rfa1 alone can promote the Dna2 nuclease activity, and we identified mutations in a helix embedded in the N-terminal domain of Rfa1 that specifically disrupt this capacity. The same RPA mutant is instead fully functional to recruit Dna2 and promote its helicase activity. Furthermore, we found residues located on the outside of the central DNA-binding OB-fold domain Rfa1-A, which are required to promote the Dna2 motor activity. Our experiments thus unexpectedly demonstrate that different domains of Rfa1 regulate Dna2 recruitment, and its nuclease and helicase activities. Consequently, the identified separation-of-function RPA variants are compromised to stimulate Dna2 in the processing of DNA breaks. The results explain phenotypes of replication-proficient but radiation-sensitive RPA mutants and illustrate the unprecedented functional interplay of RPA and Dna2. An enzymatic ensemble including Dna2 functions in DNA end resection; the function of the single-stranded DNA binding protein RPA in this complex has been underappreciated. Here the authors employ molecular modeling, biochemistry, and single molecule biophysics to reveal RPA directly promotes Dna2 recruitment, nuclease and helicase activities.
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11
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Shikha K, Sriram Bharath G, Mukhopadhyay S, Chakraborty M, Ghosh S, Khatun S, De D, Gupta AN, Ganguly A. The catalytic core of Leishmania donovani RECQ helicase unwinds a wide spectrum of DNA substrates and is stimulated by replication protein A. FEBS J 2021; 289:394-416. [PMID: 34355508 DOI: 10.1111/febs.16153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 07/11/2021] [Accepted: 08/04/2021] [Indexed: 11/29/2022]
Abstract
RecQ helicases are superfamily 2 (SF2) DNA helicases that unwind a wide spectrum of complex DNA structures in a 3' to 5' direction and are involved in maintaining genome stability. RecQ helicases from protozoan parasites have gained significant interest in recent times because of their involvement in cellular DNA repair pathways, making them important targets for drug development. In this study, we report biophysical and biochemical characterization of the catalytic core of a RecQ helicase from hemoflagellate protozoan parasite Leishmania donovani. Among the two putative RecQ helicases identified in L. donovani, we cloned, overexpressed and purified the catalytic core of LdRECQb. The catalytic core was found to be very efficient in unwinding a wide variety of DNA substrates like forked duplex, 3' tailed duplex and Holliday junction DNA. Interestingly, the helicase core also unwound blunt duplex with slightly less efficiency. The enzyme exhibited high level of DNA-stimulated ATPase activity with preferential stimulation by forked duplex, Holliday junction and 3' tailed duplex. Walker A motif lysine mutation severely affected the ATPase activity and significantly affected unwinding activity. Like many other RecQ helicases, L. donovani RECQb also possesses strand annealing activity. Unwinding of longer DNA substrates by LdRECQb catalytic core was found to be stimulated in the presence of replication protein A (LdRPA-1) from L. donovani. Detailed biochemical characterization and comparison of kinetic parameters indicate that L. donovani RECQb shares considerable functional similarity with human Bloom syndrome helicase.
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Affiliation(s)
- Kumari Shikha
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India.,School of Bioscience, Indian Institute of Technology Kharagpur, India
| | | | | | - Mayukh Chakraborty
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
| | - Susmita Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
| | - Suparna Khatun
- Department of Physics, Indian Institute of Technology Kharagpur, India
| | - Debajyoti De
- Department of Physics, Indian Institute of Technology Kharagpur, India
| | - Amar Nath Gupta
- Department of Physics, Indian Institute of Technology Kharagpur, India
| | - Agneyo Ganguly
- Department of Biotechnology, Indian Institute of Technology Kharagpur, India
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12
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Simmons RH, Rogers CM, Bochman ML. A deep dive into the RecQ interactome: something old and something new. Curr Genet 2021; 67:761-767. [PMID: 33961099 DOI: 10.1007/s00294-021-01190-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 11/26/2022]
Abstract
RecQ family helicases are found in all domains of life and play roles in multiple processes that underpin genomic integrity. As such, they are often referred to as guardians or caretakers of the genome. Despite their importance, however, there is still much we do not know about their basic functions in vivo, nor do we fully understand how they interact in organisms that encode more than one RecQ family member. We recently took a multi-omics approach to better understand the Saccharomyces cerevisiae Hrq1 helicase and its interaction with Sgs1, with these enzymes being the functional homologs of the disease-linked RECQL4 and BLM helicases, respectively. Using synthetic genetic array analyses, immuno-precipitation coupled to mass spectrometry, and RNA-seq, we found that Hrq1 and Sgs1 likely participate in many pathways outside of the canonical DNA recombination and repair functions for which they are already known. For instance, connections to transcription, ribosome biogenesis, and chromatin/chromosome organization were uncovered. These recent results are briefly detailed with respect to current knowledge in the field, and possible follow-up experiments are suggested. In this way, we hope to gain a wholistic understanding of these RecQ helicases and how their mutation leads to genomic instability.
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Affiliation(s)
- Robert H Simmons
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN, USA
| | - Cody M Rogers
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Matthew L Bochman
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN, USA.
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13
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Chansel-Da Cruz M, Hohl M, Ceppi I, Kermasson L, Maggiorella L, Modesti M, de Villartay JP, Ileri T, Cejka P, Petrini JHJ, Revy P. A Disease-Causing Single Amino Acid Deletion in the Coiled-Coil Domain of RAD50 Impairs MRE11 Complex Functions in Yeast and Humans. Cell Rep 2020; 33:108559. [PMID: 33378670 PMCID: PMC7788285 DOI: 10.1016/j.celrep.2020.108559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/30/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022] Open
Abstract
The MRE11-RAD50-NBS1 complex plays a central role in response to DNA double-strand breaks. Here, we identify a patient with bone marrow failure and developmental defects caused by biallelic RAD50 mutations. One of the mutations creates a null allele, whereas the other (RAD50E1035Δ) leads to the loss of a single residue in the heptad repeats within the RAD50 coiled-coil domain. This mutation represents a human RAD50 separation-of-function mutation that impairs DNA repair, DNA replication, and DNA end resection without affecting ATM-dependent DNA damage response. Purified recombinant proteins indicate that RAD50E1035Δ impairs MRE11 nuclease activity. The corresponding mutation in Saccharomyces cerevisiae causes severe thermosensitive defects in both DNA repair and Tel1ATM-dependent signaling. These findings demonstrate that a minor heptad break in the RAD50 coiled coil suffices to impede MRE11 complex functions in human and yeast. Furthermore, these results emphasize the importance of the RAD50 coiled coil to regulate MRE11-dependent DNA end resection in humans.
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Affiliation(s)
- Marie Chansel-Da Cruz
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée la Ligue contre le Cancer, Paris, France; University of Paris-Sorbonne Paris Cité University, Imagine Institute, Paris, France; Genomic Vision, R&D Innovation Department, Bagneux, France
| | - Marcel Hohl
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ilaria Ceppi
- Institute for Research in Biomedicine, Università della Svizzera Italiana (USI), Faculty of Biomedical Sciences, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8093 Zürich, Switzerland
| | - Laëtitia Kermasson
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée la Ligue contre le Cancer, Paris, France; University of Paris-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | | | - Mauro Modesti
- Cancer Research Center of Marseille, CNRS UMR7258, INSERM U1068, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Jean-Pierre de Villartay
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée la Ligue contre le Cancer, Paris, France; University of Paris-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Talia Ileri
- Ankara University School of Medicine, Pediatric Hematology and Oncology, Ankara, Turkey
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera Italiana (USI), Faculty of Biomedical Sciences, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8093 Zürich, Switzerland
| | - John H J Petrini
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée la Ligue contre le Cancer, Paris, France; University of Paris-Sorbonne Paris Cité University, Imagine Institute, Paris, France.
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14
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Comprehensive Synthetic Genetic Array Analysis of Alleles That Interact with Mutation of the Saccharomyces cerevisiae RecQ Helicases Hrq1 and Sgs1. G3-GENES GENOMES GENETICS 2020; 10:4359-4368. [PMID: 33115720 PMCID: PMC7718751 DOI: 10.1534/g3.120.401709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Most eukaryotic genomes encode multiple RecQ family helicases, including five such enzymes in humans. For many years, the yeast Saccharomyces cerevisiae was considered unusual in that it only contained a single RecQ helicase, named Sgs1. However, it has recently been discovered that a second RecQ helicase, called Hrq1, resides in yeast. Both Hrq1 and Sgs1 are involved in genome integrity, functioning in processes such as DNA inter-strand crosslink repair, double-strand break repair, and telomere maintenance. However, it is unknown if these enzymes interact at a genetic, physical, or functional level as demonstrated for their human homologs. Thus, we performed synthetic genetic array (SGA) analyses of hrq1Δ and sgs1Δ mutants. As inactive alleles of helicases can demonstrate dominant phenotypes, we also performed SGA analyses on the hrq1-K318A and sgs1-K706A ATPase/helicase-null mutants, as well as all combinations of deletion and inactive double mutants. We crossed these eight query strains (hrq1Δ, sgs1Δ, hrq1-K318A, sgs1-K706A, hrq1Δ sgs1Δ, hrq1Δ sgs1-K706A, hrq1-K318A sgs1Δ, and hrq1-K318A sgs1-K706A) to the S. cerevisiae single gene deletion and temperature-sensitive allele collections to generate double and triple mutants and scored them for synthetic positive and negative genetic effects based on colony growth. These screens identified hundreds of synthetic interactions, supporting the known roles of Hrq1 and Sgs1 in DNA repair, as well as suggesting novel connections to rRNA processing, mitochondrial DNA maintenance, transcription, and lagging strand synthesis during DNA replication.
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15
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C-Terminal HA Tags Compromise Function and Exacerbate Phenotypes of Saccharomyces cerevisiae Bloom's Helicase Homolog Sgs1 SUMOylation-Associated Mutants. G3-GENES GENOMES GENETICS 2020; 10:2811-2818. [PMID: 32540865 PMCID: PMC7407464 DOI: 10.1534/g3.120.401324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The Sgs1 helicase and Top3-Rmi1 decatenase form a complex that affects homologous recombination outcomes during the mitotic cell cycle and during meiosis. Previous studies have reported that Sgs1-Top3-Rmi1 function is regulated by SUMOylation that is catalyzed by the Smc5-Smc6-Mms21 complex. These studies used strains in which SGS1 was C-terminally tagged with three or six copies of a human influenza hemagglutinin-derived epitope tag (3HA and 6HA). They identified SGS1 mutants that affect its SUMOylation, which we will refer to as SGS1 SUMO-site mutants. In previous work, these mutants showed phenotypes consistent with substantial loss of Sgs1-Top3-Rmi1 function during the mitotic cell cycle. We find that the reported phenotypes are largely due to the presence of the HA epitope tags. Untagged SGS1 SUMO-site mutants show either wild-type or weak hypomorphic phenotypes, depending on the assay. These phenotypes are exacerbated by both 6HA and 3HA epitope tags in two different S. cerevisiae strain backgrounds. Importantly, a C-terminal 6HA tag confers strong hypomorphic or null phenotypes on an otherwise wild-type Sgs1 protein. Taken together, these results suggest that the HA epitope tags used in previous studies seriously compromise Sgs1 function. Furthermore, they raise the possibilities either that sufficient SUMOylation of the Sgs1-Top3-Rmi1 complex might still occur in the SUMO-site mutants isolated, or that Smc5-Smc6-Mms21-mediated SUMOylation plays a minor role in the regulation of Sgs1-Top3-Rmi1 during recombination.
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16
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Zacheja T, Toth A, Harami GM, Yang Q, Schwindt E, Kovács M, Paeschke K, Burkovics P. Mgs1 protein supports genome stability via recognition of G-quadruplex DNA structures. FASEB J 2020; 34:12646-12662. [PMID: 32748509 DOI: 10.1096/fj.202000886r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/19/2020] [Accepted: 07/10/2020] [Indexed: 01/02/2023]
Abstract
The integrity of the genetic material is crucial for every organism. One intrinsic attack to genome stability is stalling of the replication fork which can result in DNA breakage. Several factors, such as DNA lesions or the formation of stable secondary structures (eg, G-quadruplexes) can lead to replication fork stalling. G-quadruplexes (G4s) are well-characterized stable secondary DNA structures that can form within specific single-stranded DNA sequence motifs and have been shown to block/pause the replication machinery. In most genomes several helicases have been described to regulate G4 unfolding to preserve genome integrity, however, different experiments raise the hypothesis that processing of G4s during DNA replication is more complex and requires additional, so far unknown, proteins. Here, we show that the Saccharomyces cerevisiae Mgs1 protein robustly binds to G4 structures in vitro and preferentially acts at regions with a strong potential to form G4 structures in vivo. Our results suggest that Mgs1 binds to G4-forming sites and has a role in the maintenance of genome integrity.
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Affiliation(s)
- Theresa Zacheja
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Agnes Toth
- Biological Research Centre, Institute of Genetics, Szeged, Hungary.,Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Gabor M Harami
- ELTE-MTA Momentum Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Qianlu Yang
- Department of Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany.,Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, China
| | - Eike Schwindt
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Mihály Kovács
- ELTE-MTA Momentum Motor Enzymology Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Katrin Paeschke
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany.,Department of Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Peter Burkovics
- Biological Research Centre, Institute of Genetics, Szeged, Hungary
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17
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Rogers CM, Lee CY, Parkins S, Buehler NJ, Wenzel S, Martínez-Márquez F, Takagi Y, Myong S, Bochman ML. The yeast Hrq1 helicase stimulates Pso2 translesion nuclease activity and thereby promotes DNA interstrand crosslink repair. J Biol Chem 2020; 295:8945-8957. [PMID: 32371399 PMCID: PMC7335788 DOI: 10.1074/jbc.ra120.013626] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/05/2020] [Indexed: 12/11/2022] Open
Abstract
DNA interstrand crosslink (ICL) repair requires a complex network of DNA damage response pathways. Removal of the ICL lesions is vital, as they are physical barriers to essential DNA processes that require the separation of duplex DNA, such as replication and transcription. The Fanconi anemia (FA) pathway is the principal mechanism for ICL repair in metazoans and is coupled to DNA replication. In Saccharomyces cerevisiae, a vestigial FA pathway is present, but ICLs are predominantly repaired by a pathway involving the Pso2 nuclease, which is hypothesized to use its exonuclease activity to digest through the lesion to provide access for translesion polymerases. However, Pso2 lacks translesion nuclease activity in vitro, and mechanistic details of this pathway are lacking, especially relative to FA. We recently identified the Hrq1 helicase, a homolog of the disease-linked enzyme RecQ-like helicase 4 (RECQL4), as a component of Pso2-mediated ICL repair. Here, using genetic, biochemical, and biophysical approaches, including single-molecule FRET (smFRET)- and gel-based nuclease assays, we show that Hrq1 stimulates the Pso2 nuclease through a mechanism that requires Hrq1 catalytic activity. Importantly, Hrq1 also stimulated Pso2 translesion nuclease activity through a site-specific ICL in vitro We noted that stimulation of Pso2 nuclease activity is specific to eukaryotic RecQ4 subfamily helicases, and genetic and biochemical data suggest that Hrq1 likely interacts with Pso2 through their N-terminal domains. These results advance our understanding of FA-independent ICL repair and establish a role for the RecQ4 helicases in the repair of these detrimental DNA lesions.
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Affiliation(s)
- Cody M Rogers
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Chun-Ying Lee
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Samuel Parkins
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Nicholas J Buehler
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Sabine Wenzel
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Francisco Martínez-Márquez
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Yuichiro Takagi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Matthew L Bochman
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA.
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18
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Grigaitis R, Ranjha L, Wild P, Kasaciunaite K, Ceppi I, Kissling V, Henggeler A, Susperregui A, Peter M, Seidel R, Cejka P, Matos J. Phosphorylation of the RecQ Helicase Sgs1/BLM Controls Its DNA Unwinding Activity during Meiosis and Mitosis. Dev Cell 2020; 53:706-723.e5. [DOI: 10.1016/j.devcel.2020.05.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 03/18/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022]
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19
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Sandhu R, Monge Neria F, Monge Neria J, Chen X, Hollingsworth NM, Börner GV. DNA Helicase Mph1 FANCM Ensures Meiotic Recombination between Parental Chromosomes by Dissociating Precocious Displacement Loops. Dev Cell 2020; 53:458-472.e5. [PMID: 32386601 DOI: 10.1016/j.devcel.2020.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 02/09/2020] [Accepted: 04/10/2020] [Indexed: 02/07/2023]
Abstract
Meiotic pairing between parental chromosomes (homologs) is required for formation of haploid gametes. Homolog pairing depends on recombination initiation via programmed double-strand breaks (DSBs). Although DSBs appear prior to pairing, the homolog, rather than the sister chromatid, is used as repair partner for crossing over. Here, we show that Mph1, the budding yeast ortholog of Fanconi anemia helicase FANCM, prevents precocious DSB strand exchange between sister chromatids before homologs have completed pairing. By dissociating precocious DNA displacement loops (D-loops) between sister chromatids, Mph1FANCM ensures high levels of crossovers and non-crossovers between homologs. Later-occurring recombination events are protected from Mph1-mediated dissociation by synapsis protein Zip1. Increased intersister repair in absence of Mph1 triggers a shift among remaining interhomolog events from non-crossovers to crossover-specific strand exchange, explaining Mph1's apparent anti-crossover function. Our findings identify temporal coordination between DSB strand exchange and homolog pairing as a critical determinant for recombination outcome.
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Affiliation(s)
- Rima Sandhu
- Center for Gene Regulation in Health and Disease and Department of Biological Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Francisco Monge Neria
- Center for Gene Regulation in Health and Disease and Department of Biological Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Jesús Monge Neria
- Center for Gene Regulation in Health and Disease and Department of Biological Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Xiangyu Chen
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Nancy M Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - G Valentin Börner
- Center for Gene Regulation in Health and Disease and Department of Biological Sciences, Cleveland State University, Cleveland, OH 44115, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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20
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Yan Z, Xue C, Kumar S, Crickard JB, Yu Y, Wang W, Pham N, Li Y, Niu H, Sung P, Greene EC, Ira G. Rad52 Restrains Resection at DNA Double-Strand Break Ends in Yeast. Mol Cell 2019; 76:699-711.e6. [PMID: 31542296 DOI: 10.1016/j.molcel.2019.08.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/26/2019] [Accepted: 08/20/2019] [Indexed: 12/29/2022]
Abstract
Rad52 is a key factor for homologous recombination (HR) in yeast. Rad52 helps assemble Rad51-ssDNA nucleoprotein filaments that catalyze DNA strand exchange, and it mediates single-strand DNA annealing. We find that Rad52 has an even earlier function in HR in restricting DNA double-stranded break ends resection that generates 3' single-stranded DNA (ssDNA) tails. In fission yeast, Exo1 is the primary resection nuclease, with the helicase Rqh1 playing a minor role. We demonstrate that the choice of two extensive resection pathways is regulated by Rad52. In rad52 cells, the resection rate increases from ∼3-5 kb/h up to ∼10-20 kb/h in an Rqh1-dependent manner, while Exo1 becomes dispensable. Budding yeast Rad52 similarly inhibits Sgs1-dependent resection. Single-molecule analysis with purified budding yeast proteins shows that Rad52 competes with Sgs1 for DNA end binding and inhibits Sgs1 translocation along DNA. These results identify a role for Rad52 in limiting ssDNA generated by end resection.
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Affiliation(s)
- Zhenxin Yan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chaoyou Xue
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Sandeep Kumar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - J Brooks Crickard
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Yang Yu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Nhung Pham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuxi Li
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Hengyao Niu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA.
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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21
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Kasaciunaite K, Fettes F, Levikova M, Daldrop P, Anand R, Cejka P, Seidel R. Competing interaction partners modulate the activity of Sgs1 helicase during DNA end resection. EMBO J 2019; 38:e101516. [PMID: 31268598 PMCID: PMC6601037 DOI: 10.15252/embj.2019101516] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/24/2019] [Accepted: 05/08/2019] [Indexed: 11/09/2022] Open
Abstract
DNA double-strand break repair by homologous recombination employs long-range resection of the 5' DNA ends at the break points. In Saccharomyces cerevisiae, this process can be performed by the RecQ helicase Sgs1 and the helicase-nuclease Dna2. Though functional interplay between them has been shown, it remains unclear whether and how these proteins cooperate on the molecular level. Here, we resolved the dynamics of DNA unwinding by Sgs1 at the single-molecule level and investigated Sgs1 regulation by Dna2, the single-stranded DNA-binding protein RPA, and the Top3-Rmi1 complex. We found that Dna2 modulates the velocity of Sgs1, indicating that during end resection both proteins form a functional complex and couple their activities. Sgs1 drives DNA unwinding and feeds single-stranded DNA to Dna2 for degradation. RPA was found to regulate the processivity and the affinity of Sgs1 to the DNA fork, while Top3-Rmi1 modulated the velocity of Sgs1. We hypothesize that the differential regulation of Sgs1 activity by its protein partners is important to support diverse cellular functions of Sgs1 during the maintenance of genome stability.
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Affiliation(s)
- Kristina Kasaciunaite
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Fergus Fettes
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
| | - Maryna Levikova
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Peter Daldrop
- Institute for Molecular Cell Biology, University of Münster, Münster, Germany
| | - Roopesh Anand
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - Ralf Seidel
- Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany
- Institute for Molecular Cell Biology, University of Münster, Münster, Germany
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22
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Crickard J, Xue C, Wang W, Kwon Y, Sung P, Greene E. The RecQ helicase Sgs1 drives ATP-dependent disruption of Rad51 filaments. Nucleic Acids Res 2019; 47:4694-4706. [PMID: 30916344 PMCID: PMC6511845 DOI: 10.1093/nar/gkz186] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/06/2019] [Accepted: 03/20/2019] [Indexed: 12/21/2022] Open
Abstract
DNA helicases of the RecQ family are conserved among the three domains of life and play essential roles in genome maintenance. Mutations in several human RecQ helicases lead to diseases that are marked by cancer predisposition. The Saccharomyces cerevisiae RecQ helicase Sgs1 is orthologous to human BLM, defects in which cause the cancer-prone Bloom's Syndrome. Here, we use single-molecule imaging to provide a quantitative mechanistic understanding of Sgs1 activities on single stranded DNA (ssDNA), which is a central intermediate in all aspects of DNA metabolism. We show that Sgs1 acts upon ssDNA bound by either replication protein A (RPA) or the recombinase Rad51. Surprisingly, we find that Sgs1 utilizes a novel motor mechanism for disrupting ssDNA intermediates bound by the recombinase protein Rad51. The ability of Sgs1 to disrupt Rad51-ssDNA filaments may explain some of the defects engendered by RECQ helicase deficiencies in human cells.
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Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Chaoyou Xue
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
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23
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Ranjha L, Levikova M, Altmannova V, Krejci L, Cejka P. Sumoylation regulates the stability and nuclease activity of Saccharomyces cerevisiae Dna2. Commun Biol 2019; 2:174. [PMID: 31098407 PMCID: PMC6506525 DOI: 10.1038/s42003-019-0428-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/10/2019] [Indexed: 02/06/2023] Open
Abstract
Dna2 is an essential nuclease-helicase that acts in several distinct DNA metabolic pathways including DNA replication and recombination. To balance these functions and prevent unscheduled DNA degradation, Dna2 activities must be regulated. Here we show that Saccharomyces cerevisiae Dna2 function is controlled by sumoylation. We map the sumoylation sites to the N-terminal regulatory domain of Dna2 and show that in vitro sumoylation of recombinant Dna2 impairs its nuclease but not helicase activity. In cells, the total levels of the non-sumoylatable Dna2 variant are elevated. However, non-sumoylatable Dna2 shows impaired nuclear localization and reduced recruitment to foci upon DNA damage. Non-sumoylatable Dna2 reduces the rate of DNA end resection, as well as impedes cell growth and cell cycle progression through S phase. Taken together, these findings show that in addition to Dna2 phosphorylation described previously, Dna2 sumoylation is required for the homeostasis of the Dna2 protein function to promote genome stability.
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Affiliation(s)
- Lepakshi Ranjha
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland
| | - Maryna Levikova
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Veronika Altmannova
- Department of Biology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne’s University Hospital, 656 91 Brno, Czech Republic
| | - Lumir Krejci
- Department of Biology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne’s University Hospital, 656 91 Brno, Czech Republic
- National Center for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), 8093 Zürich, Switzerland
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24
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Godau J, Ferretti LP, Trenner A, Dubois E, von Aesch C, Marmignon A, Simon L, Kapusta A, Guérois R, Bétermier M, Sartori AA. Identification of a miniature Sae2/Ctp1/CtIP ortholog from Paramecium tetraurelia required for sexual reproduction and DNA double-strand break repair. DNA Repair (Amst) 2019; 77:96-108. [DOI: 10.1016/j.dnarep.2019.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/28/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022]
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25
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Anand R, Jasrotia A, Bundschuh D, Howard SM, Ranjha L, Stucki M, Cejka P. NBS1 promotes the endonuclease activity of the MRE11-RAD50 complex by sensing CtIP phosphorylation. EMBO J 2019; 38:e101005. [PMID: 30787182 PMCID: PMC6443204 DOI: 10.15252/embj.2018101005] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/08/2019] [Accepted: 02/01/2019] [Indexed: 11/09/2022] Open
Abstract
DNA end resection initiates DNA double-strand break repair by homologous recombination. MRE11-RAD50-NBS1 and phosphorylated CtIP perform the first resection step via MRE11-catalyzed endonucleolytic DNA cleavage. Human NBS1, more than its homologue Xrs2 in Saccharomyces cerevisiae, is crucial for this process, highlighting complex mechanisms that regulate the MRE11 nuclease in higher eukaryotes. Using a reconstituted system, we show here that NBS1, through its FHA and BRCT domains, functions as a sensor of CtIP phosphorylation. NBS1 then activates the MRE11-RAD50 nuclease through direct physical interactions with MRE11. In the absence of NBS1, MRE11-RAD50 exhibits a weaker nuclease activity, which requires CtIP but not strictly its phosphorylation. This identifies at least two mechanisms by which CtIP augments MRE11: a phosphorylation-dependent mode through NBS1 and a phosphorylation-independent mode without NBS1. In support, we show that limited DNA end resection occurs in vivo in the absence of the FHA and BRCT domains of NBS1. Collectively, our data suggest that NBS1 restricts the MRE11-RAD50 nuclease to S-G2 phase when CtIP is extensively phosphorylated. This defines mechanisms that regulate the MRE11 nuclease in DNA metabolism.
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Affiliation(s)
- Roopesh Anand
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Arti Jasrotia
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Diana Bundschuh
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Sean Michael Howard
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Lepakshi Ranjha
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Manuel Stucki
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
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26
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Crickard JB, Greene EC. Helicase Mechanisms During Homologous Recombination in Saccharomyces cerevisiae. Annu Rev Biophys 2019; 48:255-273. [PMID: 30857400 DOI: 10.1146/annurev-biophys-052118-115418] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicases are enzymes that move, manage, and manipulate nucleic acids. They can be subdivided into six super families and are required for all aspects of nucleic acid metabolism. In general, all helicases function by converting the chemical energy stored in the bond between the gamma and beta phosphates of adenosine triphosphate into mechanical work, which results in the unidirectional movement of the helicase protein along one strand of a nucleic acid. The results of this translocation activity can range from separation of strands within duplex nucleic acids to the physical remodeling or removal of nucleoprotein complexes. In this review, we focus on describing key helicases from the model organism Saccharomyces cerevisiae that contribute to the regulation of homologous recombination, which is an essential DNA repair pathway for fixing damaged chromosomes.
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Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
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27
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Regulatory control of Sgs1 and Dna2 during eukaryotic DNA end resection. Proc Natl Acad Sci U S A 2019; 116:6091-6100. [PMID: 30850524 DOI: 10.1073/pnas.1819276116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In the repair of DNA double-strand breaks by homologous recombination, the DNA break ends must first be processed into 3' single-strand DNA overhangs. In budding yeast, end processing requires the helicase Sgs1 (BLM in humans), the nuclease/helicase Dna2, Top3-Rmi1, and replication protein A (RPA). Here, we use single-molecule imaging to visualize Sgs1-dependent end processing in real-time. We show that Sgs1 is recruited to DNA ends through Top3-Rmi1-dependent or -independent means, and in both cases Sgs1 is maintained in an immoble state at the DNA ends. Importantly, the addition of Dna2 triggers processive Sgs1 translocation, but DNA resection only occurs when RPA is also present. We also demonstrate that the Sgs1-Dna2-Top3-Rmi1-RPA ensemble can efficiently disrupt nucleosomes, and that Sgs1 itself possesses nucleosome remodeling activity. Together, these results shed light on the regulatory interplay among conserved protein factors that mediate the nucleolytic processing of DNA ends in preparation for homologous recombination-mediated chromosome damage repair.
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28
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Jalan M, Oehler J, Morrow CA, Osman F, Whitby MC. Factors affecting template switch recombination associated with restarted DNA replication. eLife 2019; 8:41697. [PMID: 30667359 PMCID: PMC6358216 DOI: 10.7554/elife.41697] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
Homologous recombination helps ensure the timely completion of genome duplication by restarting collapsed replication forks. However, this beneficial function is not without risk as replication restarted by homologous recombination is prone to template switching (TS) that can generate deleterious genome rearrangements associated with diseases such as cancer. Previously we established an assay for studying TS in Schizosaccharomyces pombe (Nguyen et al., 2015). Here, we show that TS is detected up to 75 kb downstream of a collapsed replication fork and can be triggered by head-on collision between the restarted fork and RNA Polymerase III transcription. The Pif1 DNA helicase, Pfh1, promotes efficient restart and also suppresses TS. A further three conserved helicases (Fbh1, Rqh1 and Srs2) strongly suppress TS, but there is no change in TS frequency in cells lacking Fml1 or Mus81. We discuss how these factors likely influence TS.
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Affiliation(s)
- Manisha Jalan
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Judith Oehler
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Carl A Morrow
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Fekret Osman
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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29
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Klein HL, Ang KKH, Arkin MR, Beckwitt EC, Chang YH, Fan J, Kwon Y, Morten MJ, Mukherjee S, Pambos OJ, El Sayyed H, Thrall ES, Vieira-da-Rocha JP, Wang Q, Wang S, Yeh HY, Biteen JS, Chi P, Heyer WD, Kapanidis AN, Loparo JJ, Strick TR, Sung P, Van Houten B, Niu H, Rothenberg E. Guidelines for DNA recombination and repair studies: Mechanistic assays of DNA repair processes. MICROBIAL CELL 2019; 6:65-101. [PMID: 30652106 PMCID: PMC6334232 DOI: 10.15698/mic2019.01.665] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Genomes are constantly in flux, undergoing changes due to recombination, repair and mutagenesis. In vivo, many of such changes are studies using reporters for specific types of changes, or through cytological studies that detect changes at the single-cell level. Single molecule assays, which are reviewed here, can detect transient intermediates and dynamics of events. Biochemical assays allow detailed investigation of the DNA and protein activities of each step in a repair, recombination or mutagenesis event. Each type of assay is a powerful tool but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.
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Affiliation(s)
- Hannah L Klein
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Kenny K H Ang
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143, USA
| | - Michelle R Arkin
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143, USA
| | - Emily C Beckwitt
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Yi-Hsuan Chang
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Jun Fan
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Michael J Morten
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Sucheta Mukherjee
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Oliver J Pambos
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Hafez El Sayyed
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Elizabeth S Thrall
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - João P Vieira-da-Rocha
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Quan Wang
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Shuang Wang
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France.,Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France
| | - Hsin-Yi Yeh
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Julie S Biteen
- Departments of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, NO. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.,Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.,Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Terence R Strick
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, 75005 Paris, France.,Institut Jacques Monod, CNRS, UMR7592, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France.,Programme Equipe Labellisées, Ligue Contre le Cancer, 75013 Paris, France
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Bennett Van Houten
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hengyao Niu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Eli Rothenberg
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
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30
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Rogers CM, Sausen CW, Bochman ML. Gel-Based Assays for Measuring DNA Unwinding, Annealing, and Strand Exchange. Methods Mol Biol 2019; 1999:255-264. [PMID: 31127582 DOI: 10.1007/978-1-4939-9500-4_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Efficient replication and repair of the genome requires a multitude of protein-DNA transactions. These interactions can result in a variety of consequences for DNA such as the unwinding of double-stranded DNA (dsDNA) into single-stranded DNA (ssDNA), the annealing of complementary ssDNAs, or the exchange of ssDNA with one strand of a dsDNA duplex. Some DNA helicases possess all three activities, but many DNA-interacting proteins can also catalyze one or more of these reactions. Assays that quantify these activities are an important first step in characterizing these protein-DNA interactions in vitro. Here, we describe methods for the formation of dsDNA substrates and the assays that can be used to biochemically characterize proteins that can unwind, anneal, and/or exchange DNA strands.
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Affiliation(s)
- Cody M Rogers
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Christopher W Sausen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Matthew L Bochman
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA.
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31
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D'Alessandro G, Whelan DR, Howard SM, Vitelli V, Renaudin X, Adamowicz M, Iannelli F, Jones-Weinert CW, Lee M, Matti V, Lee WTC, Morten MJ, Venkitaraman AR, Cejka P, Rothenberg E, d'Adda di Fagagna F. BRCA2 controls DNA:RNA hybrid level at DSBs by mediating RNase H2 recruitment. Nat Commun 2018; 9:5376. [PMID: 30560944 PMCID: PMC6299093 DOI: 10.1038/s41467-018-07799-2] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/27/2018] [Indexed: 02/02/2023] Open
Abstract
DNA double-strand breaks (DSBs) are toxic DNA lesions, which, if not properly repaired, may lead to genomic instability, cell death and senescence. Damage-induced long non-coding RNAs (dilncRNAs) are transcribed from broken DNA ends and contribute to DNA damage response (DDR) signaling. Here we show that dilncRNAs play a role in DSB repair by homologous recombination (HR) by contributing to the recruitment of the HR proteins BRCA1, BRCA2, and RAD51, without affecting DNA-end resection. In S/G2-phase cells, dilncRNAs pair to the resected DNA ends and form DNA:RNA hybrids, which are recognized by BRCA1. We also show that BRCA2 directly interacts with RNase H2, mediates its localization to DSBs in the S/G2 cell-cycle phase, and controls DNA:RNA hybrid levels at DSBs. These results demonstrate that regulated DNA:RNA hybrid levels at DSBs contribute to HR-mediated repair.
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Affiliation(s)
| | - Donna Rose Whelan
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Sean Michael Howard
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vela 6, Bellinzona, 6500, Switzerland
| | - Valerio Vitelli
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Xavier Renaudin
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XZ, UK
| | - Marek Adamowicz
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RH, UK
| | - Fabio Iannelli
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | | | - MiYoung Lee
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XZ, UK
| | - Valentina Matti
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Wei Ting C Lee
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Michael John Morten
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | | | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vela 6, Bellinzona, 6500, Switzerland
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, Otto-Stern-Weg 3, Zurich, 8093, Switzerland
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY, 10016, USA
| | - Fabrizio d'Adda di Fagagna
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, Pavia, 27100, Italy.
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32
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Reginato G, Cannavo E, Cejka P. Physiological protein blocks direct the Mre11-Rad50-Xrs2 and Sae2 nuclease complex to initiate DNA end resection. Genes Dev 2018; 31:2325-2330. [PMID: 29321179 PMCID: PMC5795779 DOI: 10.1101/gad.308254.117] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/07/2017] [Indexed: 11/16/2022]
Abstract
Reginato et al. report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5′-terminated DNA strands at break sites. Following initial endonucleolytic cleavage past the obstacle, Exo1 specifically extends the resection track, leading to the generation of long 3′ overhangs that are required for homologous recombination. DNA double-strand break repair by homologous recombination is initiated by DNA end resection, which is commenced by the Mre11–Rad50–Xrs2 complex and Sae2 in yeast. Here we report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5′-terminated DNA strands at break sites. Following initial endonucleolytic cleavage past the obstacle, Exo1 specifically extends the resection track, leading to the generation of long 3′ overhangs that are required for homologous recombination. These experiments provide mechanistic insights into how short-range and long-range DNA end resection enzymes overcome obstacles near broken DNA ends to initiate recombination.
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Affiliation(s)
- Giordano Reginato
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich 8093, Switzerland
| | - Elda Cannavo
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona 6500, Switzerland.,Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich 8093, Switzerland
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33
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Taglialatela A, Alvarez S, Leuzzi G, Sannino V, Ranjha L, Huang JW, Madubata C, Anand R, Levy B, Rabadan R, Cejka P, Costanzo V, Ciccia A. Restoration of Replication Fork Stability in BRCA1- and BRCA2-Deficient Cells by Inactivation of SNF2-Family Fork Remodelers. Mol Cell 2017; 68:414-430.e8. [PMID: 29053959 DOI: 10.1016/j.molcel.2017.09.036] [Citation(s) in RCA: 264] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/17/2017] [Accepted: 09/25/2017] [Indexed: 12/13/2022]
Abstract
To ensure the completion of DNA replication and maintenance of genome integrity, DNA repair factors protect stalled replication forks upon replication stress. Previous studies have identified a critical role for the tumor suppressors BRCA1 and BRCA2 in preventing the degradation of nascent DNA by the MRE11 nuclease after replication stress. Here we show that depletion of SMARCAL1, a SNF2-family DNA translocase that remodels stalled forks, restores replication fork stability and reduces the formation of replication stress-induced DNA breaks and chromosomal aberrations in BRCA1/2-deficient cells. In addition to SMARCAL1, other SNF2-family fork remodelers, including ZRANB3 and HLTF, cause nascent DNA degradation and genomic instability in BRCA1/2-deficient cells upon replication stress. Our observations indicate that nascent DNA degradation in BRCA1/2-deficient cells occurs as a consequence of MRE11-dependent nucleolytic processing of reversed forks generated by fork remodelers. These studies provide mechanistic insights into the processes that cause genome instability in BRCA1/2-deficient cells.
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Affiliation(s)
- Angelo Taglialatela
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Silvia Alvarez
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Giuseppe Leuzzi
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Vincenzo Sannino
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Lepakshi Ranjha
- Institute for Research in Biomedicine, Università della Svizzera Italiana, 6500 Bellinzona, Switzerland
| | - Jen-Wei Huang
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Chioma Madubata
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA; Department of Biomedical Informatics, Columbia University Medical Center, New York, NY 10032, USA
| | - Roopesh Anand
- Institute for Research in Biomedicine, Università della Svizzera Italiana, 6500 Bellinzona, Switzerland
| | - Brynn Levy
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - Raul Rabadan
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA; Department of Biomedical Informatics, Columbia University Medical Center, New York, NY 10032, USA
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera Italiana, 6500 Bellinzona, Switzerland; Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Vincenzo Costanzo
- DNA Metabolism Laboratory, IFOM, FIRC Institute for Molecular Oncology, 20139 Milan, Italy
| | - Alberto Ciccia
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA.
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34
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Chang EYC, Novoa CA, Aristizabal MJ, Coulombe Y, Segovia R, Chaturvedi R, Shen Y, Keong C, Tam AS, Jones SJM, Masson JY, Kobor MS, Stirling PC. RECQ-like helicases Sgs1 and BLM regulate R-loop-associated genome instability. J Cell Biol 2017; 216:3991-4005. [PMID: 29042409 PMCID: PMC5716281 DOI: 10.1083/jcb.201703168] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/16/2017] [Accepted: 09/18/2017] [Indexed: 01/01/2023] Open
Abstract
Sgs1, the orthologue of human Bloom's syndrome helicase BLM, is a yeast DNA helicase functioning in DNA replication and repair. We show that SGS1 loss increases R-loop accumulation and sensitizes cells to transcription-replication collisions. Yeast lacking SGS1 accumulate R-loops and γ-H2A at sites of Sgs1 binding, replication pausing regions, and long genes. The mutation signature of sgs1Δ reveals copy number changes flanked by repetitive regions with high R-loop-forming potential. Analysis of BLM in Bloom's syndrome fibroblasts or by depletion of BLM from human cancer cells confirms a role for Sgs1/BLM in suppressing R-loop-associated genome instability across species. In support of a potential direct effect, BLM is found physically proximal to DNA:RNA hybrids in human cells, and can efficiently unwind R-loops in vitro. Together, our data describe a conserved role for Sgs1/BLM in R-loop suppression and support an increasingly broad view of DNA repair and replication fork stabilizing proteins as modulators of R-loop-mediated genome instability.
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Affiliation(s)
| | - Carolina A Novoa
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | | | - Yan Coulombe
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Romulo Segovia
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | - Richa Chaturvedi
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Yaoqing Shen
- Michael Smith Genome Sciences Centre, Vancouver, Canada
| | - Christelle Keong
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada
| | - Annie S Tam
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Steven J M Jones
- Michael Smith Genome Sciences Centre, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, Centre Hospitalier Universitaire de Québec Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Michael S Kobor
- Centre for Molecular Medicine and Therapeutics, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Peter C Stirling
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada .,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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35
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Shi J, Liu NN, Yang YT, Xi XG. Purification and enzymatic characterization of Gallus gallus BLM helicase. J Biochem 2017; 162:183-191. [PMID: 28338731 DOI: 10.1093/jb/mvx013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/30/2017] [Indexed: 11/12/2022] Open
Abstract
Mutations in human BLM helicase give rise to the autosomal recessive Bloom syndrome, which shows high predisposition to types of malignant tumours. Though lots of biochemical and structural investigations have shed lights on the helicase core, structural investigations of the whole BLM protein are still limited due to its low stability and production. Here by comparing with the expression systems and functions of other BLM homologues, we developed the heterologous high-level expression and high-yield purification systems for Gallus gallus BLM (gBLM) in Escherichia coli. Subsequent DNA binding and unwinding determinations demonstrated that gBLM was a vigorous atypical DNA structure specific helicase, which not only showed high preference for the 3'-tailed DNA structures but also could efficiently unwind bubble DNA structures with blunt-ends, indicating its biological roles in processing DNA metabolism intermediates. Further comparative analysis between gBLM and gBLM Core revealed that the long N-terminal domain facilitated the binding affinity of forked and bubble DNA structures and it was also required for the DNA unwinding activities of gBLM. Thus, we present the first enzymatic characterization of gBLM and its N-terminal domain, providing a new model for probing the mechanism and structure of human BLM.
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Affiliation(s)
- Jing Shi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Na-Nv Liu
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yan-Tao Yang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xu-Guang Xi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.,Laboratoire de Biologie et Pharmacologie Appliquée, ENS de Cachan, Université Paris-Saclay, CNRS, 61 Avenue du Présidnt Wilson, Cachan 94235, France
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36
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Rogers CM, Wang JCY, Noguchi H, Imasaki T, Takagi Y, Bochman ML. Yeast Hrq1 shares structural and functional homology with the disease-linked human RecQ4 helicase. Nucleic Acids Res 2017; 45:5217-5230. [PMID: 28334827 PMCID: PMC5605238 DOI: 10.1093/nar/gkx151] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 02/22/2017] [Indexed: 12/14/2022] Open
Abstract
The five human RecQ helicases participate in multiple processes required to maintain genome integrity. Of these, the disease-linked RecQ4 is the least studied because it poses many technical challenges. We previously demonstrated that the yeast Hrq1 helicase displays similar functions to RecQ4 in vivo, and here, we report the biochemical and structural characterization of these enzymes. In vitro, Hrq1 and RecQ4 are DNA-stimulated ATPases and robust helicases. Further, these activities were sensitive to DNA sequence and structure, with the helicases preferentially unwinding D-loops. Consistent with their roles at telomeres, telomeric repeat sequence DNA also stimulated binding and unwinding by these enzymes. Finally, electron microscopy revealed that Hrq1 and RecQ4 share similar structural features. These results solidify Hrq1 as a true RecQ4 homolog and position it as the premier model to determine how RecQ4 mutations lead to genomic instability and disease.
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Affiliation(s)
- Cody M Rogers
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | | | - Hiroki Noguchi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Tsuyoshi Imasaki
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yuichiro Takagi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Matthew L Bochman
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
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37
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Levikova M, Pinto C, Cejka P. The motor activity of DNA2 functions as an ssDNA translocase to promote DNA end resection. Genes Dev 2017; 31:493-502. [PMID: 28336515 PMCID: PMC5393063 DOI: 10.1101/gad.295196.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/13/2017] [Indexed: 11/25/2022]
Abstract
Here, Levikova et al. show that the motor activity of both recombinant yeast and human DNA2 promotes efficient degradation of long stretches of ssDNA, particularly in the presence of the replication protein A. Their results support a model of DNA2 and the RecQ family helicase partner forming a bidirectional motor machine in which the RecQ family helicase is the lead helicase, and the motor of DNA2 functions as a ssDNA translocase to promote degradation of 5′-terminated DNA. DNA2 nuclease–helicase functions in DNA replication and recombination. This requires the nuclease of DNA2, while, in contrast, the role of the helicase activity has been unclear. We now show that the motor activity of both recombinant yeast and human DNA2 promotes efficient degradation of long stretches of ssDNA, particularly in the presence of the replication protein A. This degradation is further stimulated by a direct interaction with a cognate RecQ family helicase, which functions with DNA2 in DNA end resection to initiate homologous recombination. Consequently, helicase-deficient yeast dna2 K1080E cells display reduced resection speed of HO-induced DNA double-strand breaks. These results support a model of DNA2 and the RecQ family helicase partner forming a bidirectional motor machine, where the RecQ family helicase is the lead helicase, and the motor of DNA2 functions as a ssDNA translocase to promote degradation of 5′-terminated DNA.
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Affiliation(s)
- Maryna Levikova
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland
| | - Cosimo Pinto
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland.,Institute for Research in Biomedicine, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
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38
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Control of DNA end resection by yeast Hmo1p affects efficiency of DNA end-joining. DNA Repair (Amst) 2017; 53:15-23. [PMID: 28336179 DOI: 10.1016/j.dnarep.2017.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/03/2017] [Accepted: 03/07/2017] [Indexed: 11/20/2022]
Abstract
The primary pathways for DNA double strand break (DSB) repair are homologous recombination (HR) and non-homologous end-joining (NHEJ). The choice between HR and NHEJ is influenced by the extent of DNA end resection, as extensive resection is required for HR but repressive to NHEJ. Conversely, association of the DNA end-binding protein Ku, which is integral to classical NHEJ, inhibits resection. In absence of key NHEJ components, a third repair pathway is exposed; this alternative-end joining (A-EJ) is a highly error-prone process that uses micro-homologies at the breakpoints and is initiated by DNA end resection. In Saccharomyces cerevisiae, the high mobility group protein Hmo1p has been implicated in controlling DNA end resection, suggesting its potential role in repair pathway choice. Using a plasmid end-joining assay, we show here that absence of Hmo1p results in reduced repair efficiency and accuracy, indicating that Hmo1p promotes end-joining; this effect is only observed on DNA with protruding ends. Notably, inhibition of DNA end resection in an hmo1Δ strain restores repair efficiency to the levels observed in wild-type cells. In absence of Ku, HMO1 deletion also reduces repair efficiency further, while inhibition of resection restores repair efficiency to the levels observed in kuΔ. We suggest that Hmo1p functions to control DNA end resection, thereby preventing error-prone A-EJ repair and directing repairs towards classical NHEJ. The very low efficiency of DSB repair in kuΔhmo1Δ cells further suggests that excessive DNA resection is inhibitory for A-EJ.
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39
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Lorenz A. Modulation of meiotic homologous recombination by DNA helicases. Yeast 2017; 34:195-203. [PMID: 27930825 DOI: 10.1002/yea.3227] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/28/2016] [Accepted: 11/28/2016] [Indexed: 12/20/2022] Open
Abstract
DNA helicases are ATP-driven motor proteins which translocate along DNA capable of dismantling DNA-DNA interactions and/or removing proteins bound to DNA. These biochemical capabilities make DNA helicases main regulators of crucial DNA metabolic processes, including DNA replication, DNA repair, and genetic recombination. This budding topic will focus on reviewing the function of DNA helicases important for homologous recombination during meiosis, and discuss recent advances in how these modulators of meiotic recombination are themselves regulated. The emphasis is placed on work in the two model yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, which has vastly expanded our understanding of meiotic homologous recombination, a process whose correct execution is instrumental for healthy gamete formation, and thus functioning sexual reproduction. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Alexander Lorenz
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
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40
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Mojumdar A, De March M, Marino F, Onesti S. The Human RecQ4 Helicase Contains a Functional RecQ C-terminal Region (RQC) That Is Essential for Activity. J Biol Chem 2016; 292:4176-4184. [PMID: 27998982 DOI: 10.1074/jbc.m116.767954] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/18/2016] [Indexed: 11/06/2022] Open
Abstract
RecQ helicases are essential in the maintenance of genome stability. Five paralogues (RecQ1, Bloom, Werner, RecQ4, and RecQ5) are found in human cells, with distinct but overlapping roles. Mutations in human RecQ4 give rise to three distinct genetic disorders (Rothmund-Thomson, RAPADILINO, and Baller-Gerold syndromes), characterized by genetic instability, growth deficiency, and predisposition to cancer. Previous studies suggested that RecQ4 was unique because it did not seem to contain a RecQ C-terminal region (RQC) found in the other RecQ paralogues; such a region consists of a zinc domain and a winged helix domain and plays an important role in enzyme activity. However, our recent bioinformatic analysis identified in RecQ4 a putative RQC. To experimentally confirm this hypothesis, we report the purification and characterization of the catalytic core of human RecQ4. Inductively coupled plasma-atomic emission spectrometry detected the unusual presence of two zinc clusters within the zinc domain, consistent with the bioinformatic prediction. Analysis of site-directed mutants, targeting key RQC residues (putative zinc ligands and the aromatic residue predicted to be at the tip of the winged helix β-hairpin), showed a decrease in DNA binding, unwinding, and annealing, as expected for a functional RQC domain. Low resolution structural information obtained by small angle X-ray scattering data suggests that RecQ4 interacts with DNA in a manner similar to RecQ1, whereas the winged helix domain may assume alternative conformations, as seen in the bacterial enzymes. These combined results experimentally confirm the presence of a functional RQC domain in human RecQ4.
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Affiliation(s)
- Aditya Mojumdar
- From the Structural Biology Laboratory, Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy and.,the Dipartimento di Scienze della Vita, Università degli Studi di Trieste, 34127 Trieste, Italy
| | - Matteo De March
- From the Structural Biology Laboratory, Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy and
| | - Francesca Marino
- From the Structural Biology Laboratory, Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy and
| | - Silvia Onesti
- From the Structural Biology Laboratory, Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy and
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41
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Anand R, Ranjha L, Cannavo E, Cejka P. Phosphorylated CtIP Functions as a Co-factor of the MRE11-RAD50-NBS1 Endonuclease in DNA End Resection. Mol Cell 2016; 64:940-950. [PMID: 27889449 DOI: 10.1016/j.molcel.2016.10.017] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/26/2016] [Accepted: 10/13/2016] [Indexed: 12/26/2022]
Abstract
To repair a DNA double-strand break (DSB) by homologous recombination (HR), the 5'-terminated strand of the DSB must be resected. The human MRE11-RAD50-NBS1 (MRN) and CtIP proteins were implicated in the initiation of DNA end resection, but the underlying mechanism remained undefined. Here, we show that CtIP is a co-factor of the MRE11 endonuclease activity within the MRN complex. This function is absolutely dependent on CtIP phosphorylation that includes the key cyclin-dependent kinase target motif at Thr-847. Unlike in yeast, where the Xrs2/NBS1 subunit is dispensable in vitro, NBS1 is absolutely required in the human system. The MRE11 endonuclease in conjunction with RAD50, NBS1, and phosphorylated CtIP preferentially cleaves 5'-terminated DNA strands near DSBs. Our results define the initial step of HR that is particularly relevant for the processing of DSBs bearing protein blocks.
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Affiliation(s)
- Roopesh Anand
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lepakshi Ranjha
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Elda Cannavo
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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42
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Piwko W, Mlejnkova LJ, Mutreja K, Ranjha L, Stafa D, Smirnov A, Brodersen MM, Zellweger R, Sturzenegger A, Janscak P, Lopes M, Peter M, Cejka P. The MMS22L-TONSL heterodimer directly promotes RAD51-dependent recombination upon replication stress. EMBO J 2016; 35:2584-2601. [PMID: 27797818 DOI: 10.15252/embj.201593132] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 10/02/2016] [Accepted: 10/06/2016] [Indexed: 11/09/2022] Open
Abstract
Homologous recombination (HR) is a key pathway that repairs DNA double-strand breaks (DSBs) and helps to restart stalled or collapsed replication forks. How HR supports replication upon genotoxic stress is not understood. Using in vivo and in vitro approaches, we show that the MMS22L-TONSL heterodimer localizes to replication forks under unperturbed conditions and its recruitment is increased during replication stress in human cells. MMS22L-TONSL associates with replication protein A (RPA)-coated ssDNA, and the MMS22L subunit directly interacts with the strand exchange protein RAD51. MMS22L is required for proper RAD51 assembly at DNA damage sites in vivo, and HR-mediated repair of stalled forks is abrogated in cells expressing a MMS22L mutant deficient in RAD51 interaction. Similar to the recombination mediator BRCA2, recombinant MMS22L-TONSL limits the assembly of RAD51 on dsDNA, which stimulates RAD51-ssDNA nucleoprotein filament formation and RAD51-dependent strand exchange activity in vitro Thus, by specifically regulating RAD51 activity at uncoupled replication forks, MMS22L-TONSL stabilizes perturbed replication forks by promoting replication fork reversal and stimulating their HR-mediated restart in vivo.
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Affiliation(s)
- Wojciech Piwko
- Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland
| | - Lucie J Mlejnkova
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Karun Mutreja
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Lepakshi Ranjha
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Diana Stafa
- Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland
| | - Alexander Smirnov
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Mia Ml Brodersen
- Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland
| | - Ralph Zellweger
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Andreas Sturzenegger
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Pavel Janscak
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Massimo Lopes
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
| | - Matthias Peter
- Department of Biology, Institute of Biochemistry ETH Zurich, Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research University of Zurich, Zurich, Switzerland
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43
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Pavankumar TL, Exell JC, Kowalczykowski SC. Direct Fluorescent Imaging of Translocation and Unwinding by Individual DNA Helicases. Methods Enzymol 2016; 581:1-32. [PMID: 27793277 DOI: 10.1016/bs.mie.2016.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The unique translocation and DNA unwinding properties of DNA helicases can be concealed by the stochastic behavior of enzyme molecules within the necessarily large populations used in ensemble experiments. With recent technological advances, the direct visualization of helicases acting on individual DNA molecules has contributed significantly to the current understanding of their mechanisms of action and biological functions. The combination of single-molecule techniques that enable both manipulation of individual protein or DNA molecules and visualization of their actions has made it possible to literally see novel and unique biochemical characteristics that were previously masked. Here, we describe the execution and use of single-molecule fluorescence imaging techniques, focusing on methods that include optical trapping in conjunction with epifluorescent imaging, and also surface immobilization in conjunction with total internal reflection fluorescence visualization. Combined with microchannel flow cells and microfluidic control, these methods allow individual fluorescently labeled protein and DNA molecules to be imaged and tracked, affording measurement of DNA unwinding and translocation at single-molecule resolution.
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Affiliation(s)
| | - J C Exell
- University of California, Davis, CA, United States
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44
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Pinto C, Kasaciunaite K, Seidel R, Cejka P. Human DNA2 possesses a cryptic DNA unwinding activity that functionally integrates with BLM or WRN helicases. eLife 2016; 5. [PMID: 27612385 PMCID: PMC5030094 DOI: 10.7554/elife.18574] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/08/2016] [Indexed: 12/13/2022] Open
Abstract
Human DNA2 (hDNA2) contains both a helicase and a nuclease domain within the same polypeptide. The nuclease of hDNA2 is involved in a variety of DNA metabolic processes. Little is known about the role of the hDNA2 helicase. Using bulk and single-molecule approaches, we show that hDNA2 is a processive helicase capable of unwinding kilobases of dsDNA in length. The nuclease activity prevents the engagement of the helicase by competing for the same substrate, hence prominent DNA unwinding by hDNA2 alone can only be observed using the nuclease-deficient variant. We show that the helicase of hDNA2 functionally integrates with BLM or WRN helicases to promote dsDNA degradation by forming a heterodimeric molecular machine. This collectively suggests that the hDNA2 motor promotes the enzyme's capacity to degrade dsDNA in conjunction with BLM or WRN and thus promote the repair of broken DNA. DOI:http://dx.doi.org/10.7554/eLife.18574.001
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Affiliation(s)
- Cosimo Pinto
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | | | - Ralf Seidel
- Institute of Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
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45
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Chakraborty U, Alani E. Understanding how mismatch repair proteins participate in the repair/anti-recombination decision. FEMS Yeast Res 2016; 16:fow071. [PMID: 27573382 PMCID: PMC5976031 DOI: 10.1093/femsyr/fow071] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/24/2016] [Accepted: 08/24/2016] [Indexed: 01/06/2023] Open
Abstract
Mismatch repair (MMR) systems correct DNA mismatches that result from DNA polymerase misincorporation errors. Mismatches also appear in heteroduplex DNA intermediates formed during recombination between nearly identical sequences, and can be corrected by MMR or removed through an unwinding mechanism, known as anti-recombination or heteroduplex rejection. We review studies, primarily in baker's yeast, which support how specific factors can regulate the MMR/anti-recombination decision. Based on recent advances, we present models for how DNA structure, relative amounts of key repair proteins, the timely localization of repair proteins to DNA substrates and epigenetic marks can modulate this critical decision.
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Affiliation(s)
- Ujani Chakraborty
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA
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46
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Kemmerich FE, Kasaciunaite K, Seidel R. Modular magnetic tweezers for single-molecule characterizations of helicases. Methods 2016; 108:4-13. [PMID: 27402355 DOI: 10.1016/j.ymeth.2016.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 01/09/2023] Open
Abstract
Magnetic tweezers provide a versatile toolkit supporting the mechanistic investigation of helicases. In the present article, we show that custom magnetic tweezers setups are straightforward to construct and can easily be extended to provide adaptable platforms, capable of addressing a multitude of enquiries regarding the functions of these fascinating molecular machines. We first address the fundamental components of a basic magnetic tweezers scheme and review some previous results to demonstrate the versatility of this instrument. We then elaborate on several extensions to the basic magnetic tweezers scheme, and demonstrate their applications with data from ongoing research. As our methodological overview illustrates, magnetic tweezers are an extremely useful tool for the characterization of helicases and a custom built instrument can be specifically tailored to suit the experimenter's needs.
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Affiliation(s)
- Felix E Kemmerich
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany
| | - Kristina Kasaciunaite
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany
| | - Ralf Seidel
- Molecular Biophysics Group, Institute of Experimental Physics I, Universität Leipzig, 04103 Leipzig, Germany.
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47
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Saredi G, Huang H, Hammond CM, Alabert C, Bekker-Jensen S, Forne I, Reverón-Gómez N, Foster BM, Mlejnkova L, Bartke T, Cejka P, Mailand N, Imhof A, Patel DJ, Groth A. H4K20me0 marks post-replicative chromatin and recruits the TONSL–MMS22L DNA repair complex. Nature 2016; 534:714-718. [PMID: 27338793 PMCID: PMC4939875 DOI: 10.1038/nature18312] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 05/05/2016] [Indexed: 12/19/2022]
Abstract
After DNA replication, chromosomal processes including DNA repair and
transcription take place in the context of sister chromatids. While cell cycle
regulation can guide these processes globally, mechanisms to distinguish pre-
and post-replicative states locally remain unknown. Here, we reveal that new
histones incorporated during DNA replication provide a signature of
post-replicative chromatin, read by the TONSL–MMS22L1–4 homologous
recombination (HR) complex. We identify the TONSL Ankyrin Repeat Domain (ARD) as
a reader of histone H4 tails unmethylated at K20 (H4K20me0), which are specific
to new histones incorporated during DNA replication and mark post-replicative
chromatin until G2/M. Accordingly, TONSL–MMS22L binds new histones
H3–H4 both prior to and after incorporation into nucleosomes, remaining
on replicated chromatin until late G2/M. H4K20me0 recognition is required for
TONSL–MMS22L binding to chromatin and accumulation at challenged
replication forks and DNA lesions. Consequently, TONSL ARD mutants are toxic,
compromising genome stability, cell viability and resistance to replication
stress. Together, this reveals a histone reader based mechanism to recognize the
post-replicative state, offering a new approach and opportunity to understand
DNA repair with potential for targeted cancer therapy.
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Affiliation(s)
- Giulia Saredi
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Hongda Huang
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA
| | - Colin M Hammond
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Constance Alabert
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Simon Bekker-Jensen
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Denmark
| | - Ignasi Forne
- Department of Molecular Biology, Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians University, Munich, Germany
| | - Nazaret Reverón-Gómez
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Benjamin M Foster
- MRC Clinical Sciences Centre, Imperial College London, United Kingdom
| | - Lucie Mlejnkova
- Institute of Molecular Cancer Research, University of Zurich, Switzerland
| | - Till Bartke
- MRC Clinical Sciences Centre, Imperial College London, United Kingdom
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Switzerland
| | - Niels Mailand
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Denmark
| | - Axel Imhof
- Department of Molecular Biology, Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians University, Munich, Germany
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA
| | - Anja Groth
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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48
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Abstract
The repair of DNA by homologous recombination is an essential, efficient, and high-fidelity process that mends DNA lesions formed during cellular metabolism; these lesions include double-stranded DNA breaks, daughter-strand gaps, and DNA cross-links. Genetic defects in the homologous recombination pathway undermine genomic integrity and cause the accumulation of gross chromosomal abnormalities-including rearrangements, deletions, and aneuploidy-that contribute to cancer formation. Recombination proceeds through the formation of joint DNA molecules-homologously paired but metastable DNA intermediates that are processed by several alternative subpathways-making recombination a versatile and robust mechanism to repair damaged chromosomes. Modern biophysical methods make it possible to visualize, probe, and manipulate the individual molecules participating in the intermediate steps of recombination, revealing new details about the mechanics of genetic recombination. We review and discuss the individual stages of homologous recombination, focusing on common pathways in bacteria, yeast, and humans, and place particular emphasis on the molecular mechanisms illuminated by single-molecule methods.
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Affiliation(s)
- Jason C Bell
- Department of Microbiology and Molecular Genetics, and Department of Molecular and Cellular Biology, University of California, Davis, California 95616;
| | - Stephen C Kowalczykowski
- Department of Microbiology and Molecular Genetics, and Department of Molecular and Cellular Biology, University of California, Davis, California 95616;
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49
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Gaidutšik I, Sedman T, Sillamaa S, Sedman J. Irc3 is a mitochondrial DNA branch migration enzyme. Sci Rep 2016; 6:26414. [PMID: 27194389 PMCID: PMC4872236 DOI: 10.1038/srep26414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/03/2016] [Indexed: 01/03/2023] Open
Abstract
Integrity of mitochondrial DNA (mtDNA) is essential for cellular energy metabolism. In the budding yeast Saccharomyces cerevisiae, a large number of nuclear genes influence the stability of mitochondrial genome; however, most corresponding gene products act indirectly and the actual molecular mechanisms of mtDNA inheritance remain poorly characterized. Recently, we found that a Superfamily II helicase Irc3 is required for the maintenance of mitochondrial genome integrity. Here we show that Irc3 is a mitochondrial DNA branch migration enzyme. Irc3 modulates mtDNA metabolic intermediates by preferential binding and unwinding Holliday junctions and replication fork structures. Furthermore, we demonstrate that the loss of Irc3 can be complemented with mitochondrially targeted RecG of Escherichia coli. We suggest that Irc3 could support the stability of mtDNA by stimulating fork regression and branch migration or by inhibiting the formation of irregular branched molecules.
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Affiliation(s)
- Ilja Gaidutšik
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b, Tartu 51010, Estonia
| | - Tiina Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b, Tartu 51010, Estonia
| | - Sirelin Sillamaa
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b, Tartu 51010, Estonia
| | - Juhan Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b, Tartu 51010, Estonia
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50
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A Delicate Balance Between Repair and Replication Factors Regulates Recombination Between Divergent DNA Sequences in Saccharomyces cerevisiae. Genetics 2015; 202:525-40. [PMID: 26680658 DOI: 10.1534/genetics.115.184093] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022] Open
Abstract
Single-strand annealing (SSA) is an important homologous recombination mechanism that repairs DNA double strand breaks (DSBs) occurring between closely spaced repeat sequences. During SSA, the DSB is acted upon by exonucleases to reveal complementary sequences that anneal and are then repaired through tail clipping, DNA synthesis, and ligation steps. In baker's yeast, the Msh DNA mismatch recognition complex and the Sgs1 helicase act to suppress SSA between divergent sequences by binding to mismatches present in heteroduplex DNA intermediates and triggering a DNA unwinding mechanism known as heteroduplex rejection. Using baker's yeast as a model, we have identified new factors and regulatory steps in heteroduplex rejection during SSA. First we showed that Top3-Rmi1, a topoisomerase complex that interacts with Sgs1, is required for heteroduplex rejection. Second, we found that the replication processivity clamp proliferating cell nuclear antigen (PCNA) is dispensable for heteroduplex rejection, but is important for repairing mismatches formed during SSA. Third, we showed that modest overexpression of Msh6 results in a significant increase in heteroduplex rejection; this increase is due to a compromise in Msh2-Msh3 function required for the clipping of 3' tails. Thus 3' tail clipping during SSA is a critical regulatory step in the repair vs. rejection decision; rejection is favored before the 3' tails are clipped. Unexpectedly, Msh6 overexpression, through interactions with PCNA, disrupted heteroduplex rejection between divergent sequences in another recombination substrate. These observations illustrate the delicate balance that exists between repair and replication factors to optimize genome stability.
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