1
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Sonmez C, Toia B, Eickhoff P, Matei AM, El Beyrouthy M, Wallner B, Douglas ME, de Lange T, Lottersberger F. DNA-PK controls Apollo's access to leading-end telomeres. Nucleic Acids Res 2024; 52:4313-4327. [PMID: 38407308 PMCID: PMC11077071 DOI: 10.1093/nar/gkae105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 01/23/2024] [Accepted: 02/01/2024] [Indexed: 02/27/2024] Open
Abstract
The complex formed by Ku70/80 and DNA-PKcs (DNA-PK) promotes the synapsis and the joining of double strand breaks (DSBs) during canonical non-homologous end joining (c-NHEJ). In c-NHEJ during V(D)J recombination, DNA-PK promotes the processing of the ends and the opening of the DNA hairpins by recruiting and/or activating the nuclease Artemis/DCLRE1C/SNM1C. Paradoxically, DNA-PK is also required to prevent the fusions of newly replicated leading-end telomeres. Here, we describe the role for DNA-PK in controlling Apollo/DCLRE1B/SNM1B, the nuclease that resects leading-end telomeres. We show that the telomeric function of Apollo requires DNA-PKcs's kinase activity and the binding of Apollo to DNA-PK. Furthermore, AlphaFold-Multimer predicts that Apollo's nuclease domain has extensive additional interactions with DNA-PKcs, and comparison to the cryo-EM structure of Artemis bound to DNA-PK phosphorylated on the ABCDE/Thr2609 cluster suggests that DNA-PK can similarly grant Apollo access to the DNA end. In agreement, the telomeric function of DNA-PK requires the ABCDE/Thr2609 cluster. These data reveal that resection of leading-end telomeres is regulated by DNA-PK through its binding to Apollo and its (auto)phosphorylation-dependent positioning of Apollo at the DNA end, analogous but not identical to DNA-PK dependent regulation of Artemis at hairpins.
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Affiliation(s)
- Ceylan Sonmez
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Patrik Eickhoff
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Andreea Medeea Matei
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Michael El Beyrouthy
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
| | - Björn Wallner
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 58 183, Sweden
| | - Max E Douglas
- Chester Beatty Laboratories, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, NY, NY 10021, USA
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping 58 183, Sweden
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2
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Bories C, Lejour T, Adolphe F, Kermasson L, Couvé S, Tanguy L, Luszczewska G, Watzky M, Poillerat V, Garnier P, Groisman R, Ferlicot S, Richard S, Saparbaev M, Revy P, Gad S, Renaud F. DCLRE1B/Apollo germline mutations associated with renal cell carcinoma impair telomere protection. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167107. [PMID: 38430974 DOI: 10.1016/j.bbadis.2024.167107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 02/14/2024] [Accepted: 02/25/2024] [Indexed: 03/05/2024]
Abstract
Hereditary renal cell carcinoma (RCC) is caused by germline mutations in a subset of genes, including VHL, MET, FLCN, and FH. However, many familial RCC cases do not harbor mutations in the known predisposition genes. Using Whole Exome Sequencing, we identified two germline missense variants in the DCLRE1B/Apollo gene (ApolloN246I and ApolloY273H) in two unrelated families with several RCC cases. Apollo encodes an exonuclease involved in DNA Damage Response and Repair (DDRR) and telomere integrity. We characterized these two functions in the human renal epithelial cell line HKC8. The decrease or inhibition of Apollo expression sensitizes these cells to DNA interstrand crosslink damage (ICLs). HKC8 Apollo-/- cells appear defective in the DDRR and present an accumulation of telomere damage. Wild-type and mutated Apollo forms could interact with TRF2, a shelterin protein involved in telomere protection. However, only ApolloWT can rescue the telomere damage in HKC8 Apollo-/- cells. Our results strongly suggest that ApolloN246I and ApolloY273H are loss-of-function mutants that cause impaired telomere integrity and could lead to genomic instability. Altogether, our results suggest that mutations in Apollo could induce renal oncogenesis.
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Affiliation(s)
- Charlie Bories
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Thomas Lejour
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Florine Adolphe
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Laëtitia Kermasson
- Laboratory of Genome Dynamics in the Immune System, Laboratoire labellisé Ligue Nationale contre le Cancer, INSERM UMR 1163, Université de Paris, Imagine Institute, Paris, France
| | - Sophie Couvé
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Laura Tanguy
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Gabriela Luszczewska
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Manon Watzky
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Victoria Poillerat
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Pauline Garnier
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Regina Groisman
- UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Sophie Ferlicot
- UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France; Département de Pathologie, AP-HP, Université Paris-Saclay, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France
| | - Stéphane Richard
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France; Réseau National de Référence pour Cancers Rares de l'Adulte PREDIR labellisé par l'INCa, Hôpital de Bicêtre, AP-HP, et Service d'Urologie, Le Kremlin-Bicêtre, France
| | - Murat Saparbaev
- UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Laboratoire labellisé Ligue Nationale contre le Cancer, INSERM UMR 1163, Université de Paris, Imagine Institute, Paris, France
| | - Sophie Gad
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France
| | - Flore Renaud
- EPHE, PSL Université, Paris, France; UMR 9019 CNRS, Gustave Roussy, Université Paris-Saclay, 114 rue Edouard Vaillant, Villejuif 94800, France.
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3
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Myler LR, Toia B, Vaughan CK, Takai K, Matei AM, Wu P, Paull TT, de Lange T, Lottersberger F. DNA-PK and the TRF2 iDDR inhibit MRN-initiated resection at leading-end telomeres. Nat Struct Mol Biol 2023; 30:1346-1356. [PMID: 37653239 PMCID: PMC10497418 DOI: 10.1038/s41594-023-01072-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 07/18/2023] [Indexed: 09/02/2023]
Abstract
Telomeres replicated by leading-strand synthesis lack the 3' overhang required for telomere protection. Surprisingly, resection of these blunt telomeres is initiated by the telomere-specific 5' exonuclease Apollo rather than the Mre11-Rad50-Nbs1 (MRN) complex, the nuclease that acts at DNA breaks. Without Apollo, leading-end telomeres undergo fusion, which, as demonstrated here, is mediated by alternative end joining. Here, we show that DNA-PK and TRF2 coordinate the repression of MRN at blunt mouse telomeres. DNA-PK represses an MRN-dependent long-range resection, while the endonuclease activity of MRN-CtIP, which could cleave DNA-PK off of blunt telomere ends, is inhibited in vitro and in vivo by the iDDR of TRF2. AlphaFold-Multimer predicts a conserved association of the iDDR with Rad50, potentially interfering with CtIP binding and MRN endonuclease activation. We propose that repression of MRN-mediated resection is a conserved aspect of telomere maintenance and represents an ancient feature of DNA-PK and the iDDR.
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Affiliation(s)
- Logan R Myler
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Beatrice Toia
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Cara K Vaughan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Kaori Takai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
| | - Andreea M Matei
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Peng Wu
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA.
| | - Francisca Lottersberger
- Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden.
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4
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Revy P, Kannengiesser C, Bertuch AA. Genetics of human telomere biology disorders. Nat Rev Genet 2023; 24:86-108. [PMID: 36151328 DOI: 10.1038/s41576-022-00527-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2022] [Indexed: 01/24/2023]
Abstract
Telomeres are specialized nucleoprotein structures at the ends of linear chromosomes that prevent the activation of DNA damage response and repair pathways. Numerous factors localize at telomeres to regulate their length, structure and function, to avert replicative senescence or genome instability and cell death. In humans, Mendelian defects in several of these factors can result in abnormally short or dysfunctional telomeres, causing a group of rare heterogeneous premature-ageing diseases, termed telomeropathies, short-telomere syndromes or telomere biology disorders (TBDs). Here, we review the TBD-causing genes identified so far and describe their main functions associated with telomere biology. We present molecular aspects of TBDs, including genetic anticipation, phenocopy, incomplete penetrance and somatic genetic rescue, which underlie the complexity of these diseases. We also discuss the implications of phenotypic and genetic features of TBDs on fundamental aspects related to human telomere biology, ageing and cancer, as well as on diagnostic, therapeutic and clinical approaches.
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Affiliation(s)
- Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Nationale contre le Cancer, Paris, France.
- Université Paris Cité, Imagine Institute, Paris, France.
| | - Caroline Kannengiesser
- APHP Service de Génétique, Hôpital Bichat, Paris, France
- Inserm U1152, Université Paris Cité, Paris, France
| | - Alison A Bertuch
- Departments of Paediatrics and Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA
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5
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Somashekara SC, Muniyappa K. Dual targeting of Saccharomyces cerevisiae Pso2 to mitochondria and the nucleus, and its functional relevance in the repair of DNA interstrand crosslinks. G3 (BETHESDA, MD.) 2022; 12:jkac066. [PMID: 35482533 PMCID: PMC9157068 DOI: 10.1093/g3journal/jkac066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/15/2022] [Indexed: 11/12/2022]
Abstract
Repair of DNA interstrand crosslinks involves a functional interplay among different DNA surveillance and repair pathways. Previous work has shown that interstrand crosslink-inducing agents cause damage to Saccharomyces cerevisiae nuclear and mitochondrial DNA, and its pso2/snm1 mutants exhibit a petite phenotype followed by loss of mitochondrial DNA integrity and copy number. Complex as it is, the cause and underlying molecular mechanisms remains elusive. Here, by combining a wide range of approaches with in vitro and in vivo analyses, we interrogated the subcellular localization and function of Pso2. We found evidence that the nuclear-encoded Pso2 contains 1 mitochondrial targeting sequence and 2 nuclear localization signals (NLS1 and NLS2), although NLS1 resides within the mitochondrial targeting sequence. Further analysis revealed that Pso2 is a dual-localized interstrand crosslink repair protein; it can be imported into both nucleus and mitochondria and that genotoxic agents enhance its abundance in the latter. While mitochondrial targeting sequence is essential for mitochondrial Pso2 import, either NLS1 or NLS2 is sufficient for its nuclear import; this implies that the 2 nuclear localization signal motifs are functionally redundant. Ablation of mitochondrial targeting sequence abrogated mitochondrial Pso2 import, and concomitantly, raised its levels in the nucleus. Strikingly, mutational disruption of both nuclear localization signal motifs blocked the nuclear Pso2 import; at the same time, they enhanced its translocation into the mitochondria, consistent with the notion that the relationship between mitochondrial targeting sequence and nuclear localization signal motifs is competitive. However, the nuclease activity of import-deficient species of Pso2 was not impaired. The potential relevance of dual targeting of Pso2 into 2 DNA-bearing organelles is discussed.
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Affiliation(s)
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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6
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Kermasson L, Churikov D, Awad A, Smoom R, Lainey E, Touzot F, Audebert-Bellanger S, Haro S, Roger L, Costa E, Mouf M, Bottero A, Oleastro M, Abdo C, de Villartay JP, Géli V, Tzfati Y, Callebaut I, Danielian S, Soares G, Kannengiesser C, Revy P. Inherited human Apollo deficiency causes severe bone marrow failure and developmental defects. Blood 2022; 139:2427-2440. [PMID: 35007328 PMCID: PMC11022855 DOI: 10.1182/blood.2021010791] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 12/13/2021] [Indexed: 11/20/2022] Open
Abstract
Inherited bone marrow failure syndromes (IBMFSs) are a group of disorders typified by impaired production of 1 or several blood cell types. The telomere biology disorders dyskeratosis congenita (DC) and its severe variant, Høyeraal-Hreidarsson (HH) syndrome, are rare IBMFSs characterized by bone marrow failure, developmental defects, and various premature aging complications associated with critically short telomeres. We identified biallelic variants in the gene encoding the 5'-to-3' DNA exonuclease Apollo/SNM1B in 3 unrelated patients presenting with a DC/HH phenotype consisting of early-onset hypocellular bone marrow failure, B and NK lymphopenia, developmental anomalies, microcephaly, and/or intrauterine growth retardation. All 3 patients carry a homozygous or compound heterozygous (in combination with a null allele) missense variant affecting the same residue L142 (L142F or L142S) located in the catalytic domain of Apollo. Apollo-deficient cells from patients exhibited spontaneous chromosome instability and impaired DNA repair that was complemented by CRISPR/Cas9-mediated gene correction. Furthermore, patients' cells showed signs of telomere fragility that were not associated with global reduction of telomere length. Unlike patients' cells, human Apollo KO HT1080 cell lines showed strong telomere dysfunction accompanied by excessive telomere shortening, suggesting that the L142S and L142F Apollo variants are hypomorphic. Collectively, these findings define human Apollo as a genome caretaker and identify biallelic Apollo variants as a genetic cause of a hitherto unrecognized severe IBMFS that combines clinical hallmarks of DC/HH with normal telomere length.
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Affiliation(s)
- Laëtitia Kermasson
- Laboratory of Genome Dynamics in the Immune System, Laboratoire labellisé Ligue Naionale contre le Cancer, INSERM UMR 1163, Université de Paris, Imagine Institute, Paris, France
| | - Dmitri Churikov
- U1068 INSERM, Unité Mixte de Recherche (UMR) 7258 (CNRS), Equipe Labellisée Ligue Nationale Contre le Cancer, Marseille Cancer Research Center (CRCM), Institut Paoli-Calmettes, Aix Marseille University, Marseille, France
| | - Aya Awad
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem, Israel
| | - Riham Smoom
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem, Israel
| | - Elodie Lainey
- Hematology Laboratory, Robert Debré Hospital-Assistance Publique-Hôpitaux de Paris (APHP); INSERM UMR 1131-Hematology University Institute-Denis Diderot School of Medicine, Paris, France
| | - Fabien Touzot
- Department of Immunology-Rheumatology, Department of Pediatrics, Centre Hospitalier Universitaire (CHU), Sainte Justine Research Center, Université de Montréal, Montréal, Quebec, Canada
| | | | - Sophie Haro
- Department of Paediatrics and Medical Genetics, CHU de Brest, Brest, France
| | - Lauréline Roger
- Structure and Instability of Genomes laboratory, “Muséum National d'Histoire Naturelle” (MNHN), INSERM U1154, CNRS UMR 7196, Paris, France
| | - Emilia Costa
- Serviço de Pediatria, Centro Hospitalar e Universitário do Porto, Porto, Portugal
| | - Maload Mouf
- 68HAL Meddle Laboratory, Zenon Skelter Institute, Green Hills, Eggum, Norway
| | | | - Matias Oleastro
- Rheumathology and Immunology Service, Hospital Nacional de Pediatría JP Garrahan, Buenos Aires, Argentina
| | - Chrystelle Abdo
- Onco-Hematology, Assistance Publique-Hôpitaux de Paris, Université de Paris and Institut Necker Enfants Malades, Paris, France
| | - Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, Laboratoire labellisé Ligue Naionale contre le Cancer, INSERM UMR 1163, Université de Paris, Imagine Institute, Paris, France
| | - Vincent Géli
- U1068 INSERM, Unité Mixte de Recherche (UMR) 7258 (CNRS), Equipe Labellisée Ligue Nationale Contre le Cancer, Marseille Cancer Research Center (CRCM), Institut Paoli-Calmettes, Aix Marseille University, Marseille, France
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem, Israel
| | - Isabelle Callebaut
- UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France
| | - Silvia Danielian
- Department of Immunology, JP Garrahan National Hospital of Pediatrics, Buenos Aires, Argentina
| | - Gabriela Soares
- Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar e Universitário do Porto, Porto, Portugal
| | - Caroline Kannengiesser
- Service de Génétique, Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Université Paris Diderot, Paris, France
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Laboratoire labellisé Ligue Naionale contre le Cancer, INSERM UMR 1163, Université de Paris, Imagine Institute, Paris, France
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7
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Baddock H, Newman J, Yosaatmadja Y, Bielinski M, Schofield C, Gileadi O, McHugh P. A phosphate binding pocket is a key determinant of exo- versus endo-nucleolytic activity in the SNM1 nuclease family. Nucleic Acids Res 2021; 49:9294-9309. [PMID: 34387694 PMCID: PMC8450094 DOI: 10.1093/nar/gkab692] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/02/2022] Open
Abstract
The SNM1 nucleases which help maintain genome integrity are members of the metallo-β-lactamase (MBL) structural superfamily. Their conserved MBL-β-CASP-fold SNM1 core provides a molecular scaffold forming an active site which coordinates the metal ions required for catalysis. The features that determine SNM1 endo- versus exonuclease activity, and which control substrate selectivity and binding are poorly understood. We describe a structure of SNM1B/Apollo with two nucleotides bound to its active site, resembling the product state of its exonuclease reaction. The structure enables definition of key SNM1B residues that form contacts with DNA and identifies a 5' phosphate binding pocket, which we demonstrate is important in catalysis and which has a key role in determining endo- versus exonucleolytic activity across the SNM1 family. We probed the capacity of SNM1B to digest past sites of common endogenous DNA lesions and find that base modifications planar to the nucleobase can be accommodated due to the open architecture of the active site, but lesions axial to the plane of the nucleobase are not well tolerated due to constriction around the altered base. We propose that SNM1B/Apollo might employ its activity to help remove common oxidative lesions from telomeres.
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Affiliation(s)
- Hannah T Baddock
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DS, UK
| | - Joseph A Newman
- Centre for Medicines Discovery, University of Oxford, ORCRB, OX3 7DQ, UK
| | | | - Marcin Bielinski
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | | | - Opher Gileadi
- Centre for Medicines Discovery, University of Oxford, ORCRB, OX3 7DQ, UK
| | - Peter J McHugh
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DS, UK
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8
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Chen M, Wei R, Wei G, Xu M, Su Z, Zhao C, Ni T. Systematic evaluation of the effect of polyadenylation signal variants on the expression of disease-associated genes. Genome Res 2021; 31:890-899. [PMID: 33875481 PMCID: PMC8092010 DOI: 10.1101/gr.270256.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 03/02/2021] [Indexed: 01/18/2023]
Abstract
Single nucleotide variants (SNVs) within polyadenylation signals (PASs), a specific six-nucleotide sequence required for mRNA maturation, can impair RNA-level gene expression and cause human diseases. However, there is a lack of genome-wide investigation and systematic confirmation tools for identifying PAS variants. Here, we present a computational strategy to integrate the most reliable resources for discovering distinct genomic features of PAS variants and also develop a credible and convenient experimental tool to validate the effect of PAS variants on expression of disease-associated genes. This approach will greatly accelerate the deciphering of PAS variation-related human diseases.
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Affiliation(s)
- Meng Chen
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Eye & ENT Hospital, Fudan University, Shanghai, 200438, China.,Eye Institute, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, 200031, China
| | - Ran Wei
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438, China.,Department of Pathology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Gang Wei
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438, China.,MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Mingqing Xu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center of Genetics and Development, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Zhixi Su
- Singlera Genomics (Shanghai) Limited, Shanghai, 201318, China
| | - Chen Zhao
- Eye Institute, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200031, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, 200031, China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438, China.,Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, China
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9
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Herwest S, Albers C, Schmiester M, Salewsky B, Hopfenmüller W, Meyer A, Bertram L, Demuth I. The hSNM1B/Apollo variant rs11552449 is associated with cellular sensitivity towards mitomycin C and ionizing radiation. DNA Repair (Amst) 2018; 72:93-98. [DOI: 10.1016/j.dnarep.2018.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 08/03/2018] [Accepted: 09/10/2018] [Indexed: 11/30/2022]
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10
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Chen X, Liu L, Chen Y, Yang Y, Yang CY, Guo T, Lei M, Sun H, Wang S. Cyclic Peptidic Mimetics of Apollo Peptides Targeting Telomeric Repeat Binding Factor 2 (TRF2) and Apollo Interaction. ACS Med Chem Lett 2018; 9:507-511. [PMID: 29795768 DOI: 10.1021/acsmedchemlett.8b00152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 04/25/2018] [Indexed: 01/30/2023] Open
Abstract
Telomeric repeat binding factor 2 (TRF2) is a telomere-associated protein that plays an important role in the formation of the 3' single strand DNA overhang and the "T loop", two structures critical for the stability of the telomeres. Apollo is a 5'-exonuclease recruited by TRF2 to the telomere and contributes to the formation of the 3' single strand DNA overhang. Knocking down of Apollo can induce DNA damage response similar to that caused by the knocking down of TRF2. In this Letter, we report the design and synthesis of a class of cyclic peptidic mimetics of the TRFH binding motif of Apollo (ApolloTBM). We found conformational control of the C terminal residues of ApolloTBM can effectively improve the binding affinity. We have obtained a crystal structure of a cyclic peptidic Apollo peptide mimetic (34) complexed with TRF2, which provides valuable guidance to the future design of TRF2 inhibitors.
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Affiliation(s)
- Xia Chen
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 210009, China
| | | | - Yong Chen
- State Key Laboratory of Molecular Biology, National Center for Protein Science, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China
| | | | | | - Tianyue Guo
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 210009, China
| | - Ming Lei
- Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, 639 Zhizaoju Lu, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Haiying Sun
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 210009, China
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11
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SNM1B/Apollo in the DNA damage response and telomere maintenance. Oncotarget 2018; 8:48398-48409. [PMID: 28430596 PMCID: PMC5564657 DOI: 10.18632/oncotarget.16864] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/27/2017] [Indexed: 01/26/2023] Open
Abstract
hSNM1B/Apollo is a member of the highly conserved β-CASP subgroup within the MBL superfamily of proteins. It interacts with several DNA repair proteins and functions within the Fanconi anemia pathway in response to DNA interstrand crosslinks. As a shelterin accessory protein, hSNM1B/Apollo is also vital for the generation and maintenance of telomeric overhangs. In this review, we will summarize studies on hSNM1B/Apollo's function, including its contribution to DNA damage signaling, replication fork maintenance, control of topological stress and telomere protection. Furthermore, we will highlight recent studies illustrating hSNM1B/Apollo's putative role in human disease.
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12
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OLA1, a Translational Regulator of p21, Maintains Optimal Cell Proliferation Necessary for Developmental Progression. Mol Cell Biol 2016; 36:2568-82. [PMID: 27481995 DOI: 10.1128/mcb.00137-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/25/2016] [Indexed: 02/07/2023] Open
Abstract
OLA1, an Obg-family GTPase, has been implicated in eukaryotic initiation factor 2 (eIF2)-mediated translational control, but its physiological functions remain obscure. Here we report that mouse embryos lacking OLA1 have stunted growth, delayed development leading to immature organs-especially lungs-at birth, and frequent perinatal lethality. Proliferation of primary Ola1(-/-) mouse embryonic fibroblasts (MEFs) is impaired due to defective cell cycle progression, associated with reduced cyclins D1 and E1, attenuated Rb phosphorylation, and increased p21(Cip1/Waf1) Accumulation of p21 in Ola1(-/-) MEFs is due to enhanced mRNA translation and can be prevented by either reconstitution of OLA1 expression or treatment with an eIF2α dephosphorylation inhibitor, suggesting that OLA1 regulates p21 through a translational mechanism involving eIF2. With immunohistochemistry, overexpression of p21 protein was detected in Ola1-null embryos with reduced cell proliferation. Moreover, we have generated p21(-/-) Ola1(-/-) mice and found that knockout of p21 can partially rescue the growth retardation defect of Ola1(-/-) embryos but fails to rescue them from developmental delay and the lethality. These data demonstrate, for the first time, that OLA1 is required for normal progression of mammalian development. OLA1 plays an important role in promoting cell proliferation at least in part through suppression of p21 and organogenesis via factors yet to be discovered.
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13
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Munari FM, Guecheva TN, Bonatto D, Henriques JAP. New features on Pso2 protein family in DNA interstrand cross-link repair and in the maintenance of genomic integrity in Saccharomyces cerevisiae. Fungal Genet Biol 2013; 60:122-32. [PMID: 24076078 DOI: 10.1016/j.fgb.2013.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/11/2013] [Accepted: 09/15/2013] [Indexed: 11/27/2022]
Abstract
Pso2 protein, a member of the highly conserved metallo-β-lactamase (MBL) super family of nucleases, plays a central role in interstrand crosslink repair (ICL) in yeast. Pso2 protein is the founder member of a distinct group within the MBL superfamily, called β-CASP family. Three mammalian orthologs of this protein that act on DNA were identified: SNM1A, SNM1B/Apollo and SNM1C/Artemis. Yeast Pso2 and all three mammalian orthologs proteins have been shown to possess nuclease activity. Besides Pso2, ICL repair involves proteins of several DNA repair pathways. Over the last years, new homologs for human proteins have been identified in yeast. In this review, we will focus on studies clarifying the function of Pso2 protein during ICL repair in yeast, emphasizing the contribution of Brazilian research groups in this topic. New sub-pathways in the mechanisms of ICL repair, such as recently identified conserved Fanconi Anemia pathway in yeast as well as a contribution of non-homologous end joining are discussed.
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Affiliation(s)
- Fernanda Mosena Munari
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
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14
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Lu Y, Wei B, Zhang T, Chen Z, Ye J. How will telomeric complex be further contributed to our longevity? - the potential novel biomarkers of telomere complex counteracting both aging and cancer. Protein Cell 2013; 4:573-81. [PMID: 23864530 DOI: 10.1007/s13238-013-3002-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/27/2013] [Indexed: 11/29/2022] Open
Abstract
With the smooth move towards the coming expected clinical reports of anticancer pharmaceutical molecules targeting telomeres and telomerase, and also with the exciting success in the extension of lifespan by regulating telomerase activity without increased onset of oncogenesis in laboratory mouse models (Garcia-Cao et al., 2006; Jaskelioff et al., 2011), we are convinced that targeting telomeres based on telomerase will be a potential approach to conquer both aging and cancer and the idea of longevity seems to be no more mysterious. More interestingly, emerging evidences from clinical research reveal that other telomeric factors, like specific telomeric binding proteins and nonspecific telomere associated proteins also show crucial importance in aging and oncogenesis. This stems from their roles in the stability of telomere structure and in the inhibition of DNA damage response at telomeres. Uncapping these proteins from chromosome ends leads to dramatic telomere loss and telomere dysfunction which is more abrupt than those induced by telomerase inactivation. Abnormal expression of these factors results in developmental failure, aging and even oncogenesis evidenced by several experimental models and clinical cases, indicating telomere specific proteins and its associated proteins have complimentary roles to telomerase in telomere protection and controlling cellular fate. Thus, these telomeric factors might be potential clinical biomarkers for early detection or even therapeutic targets of aging and cancer. Future studies to elucidate how these proteins function in telomere protection might benefit patients suffering aging or cancer who are not sensitive to telomerase mediation.
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Affiliation(s)
- Yiming Lu
- Shanghai Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
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15
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Mason JM, Das I, Arlt M, Patel N, Kraftson S, Glover TW, Sekiguchi JM. The SNM1B/APOLLO DNA nuclease functions in resolution of replication stress and maintenance of common fragile site stability. Hum Mol Genet 2013; 22:4901-13. [PMID: 23863462 DOI: 10.1093/hmg/ddt340] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
SNM1B/Apollo is a DNA nuclease that has important functions in telomere maintenance and repair of DNA interstrand crosslinks (ICLs) within the Fanconi anemia (FA) pathway. SNM1B is required for efficient localization of key repair proteins, such as the FA protein, FANCD2, to sites of ICL damage and functions epistatically to FANCD2 in cellular survival to ICLs and homology-directed repair. The FA pathway is also activated in response to replication fork stalling. Here, we sought to determine the importance of SNM1B in cellular responses to stalled forks in the absence of a blocking lesion, such as ICLs. We found that depletion of SNM1B results in hypersensitivity to aphidicolin, a DNA polymerase inhibitor that causes replication stress. We observed that the SNM1B nuclease is required for efficient localization of the DNA repair proteins, FANCD2 and BRCA1, to subnuclear foci upon aphidicolin treatment, thereby indicating SNM1B facilitates direct repair of stalled forks. Consistent with a role for SNM1B subsequent to recognition of the lesion, we found that SNM1B is dispensable for upstream events, including activation of ATR-dependent signaling and localization of RPA, γH2AX and the MRE11/RAD50/NBS1 complex to aphidicolin-induced foci. We determined that a major consequence of SNM1B depletion is a marked increase in spontaneous and aphidicolin-induced chromosomal gaps and breaks, including breakage at common fragile sites. Thus, this study provides evidence that SNM1B functions in resolving replication stress and preventing accumulation of genomic damage.
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16
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Tavana O, Puebla-Osorio N, Kim J, Sang M, Jang S, Zhu C. Ku70 functions in addition to nonhomologous end joining in pancreatic β-cells: a connection to β-catenin regulation. Diabetes 2013; 62:2429-38. [PMID: 23474484 PMCID: PMC3712041 DOI: 10.2337/db12-1218] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The genesis of β-cells predominantly occurs through self-replication; therefore, understanding the regulation of cell proliferation is essential. We previously showed that the lack of nonhomologous end joining (NHEJ) DNA repair factor ligase IV leads to an accumulation of DNA damage that permanently halts β-cell proliferation and dramatically decreases insulin production, causing overt diabetes in a hypomorphic p53(R172P) background. In the present study, to further delineate the function of NHEJ, we analyzed mice deficient for another key NHEJ factor, Ku70, to discover the effect of cellular responses to DNA damage in pancreatic β-cells on cellular proliferation and glucose homeostasis. Analysis of Ku70(-/-) pancreatic β-cells revealed an accumulation of DNA damage and activation of p53-dependent cellular senescence similar to the results found in our earlier ligase IV deficiency study. To our surprise, Ku70(-/-) mice had significantly increased β-cell proliferation and islet expansion, heightened insulin levels, and decreased glycemia. This augmented β-cell proliferation was accompanied by an increased β-catenin level, which we propose to be responsible for this phenotype. This study highlights Ku70 as an important player not only in maintaining genomic stability through NHEJ-dependent functions, but also in regulating pancreatic β-cell proliferation, a novel NHEJ-independent function.
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Affiliation(s)
- Omid Tavana
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
| | - Nahum Puebla-Osorio
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jiseong Kim
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Mei Sang
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Stella Jang
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Chengming Zhu
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
- Corresponding author: Chengming Zhu,
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17
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Wu XJ, Zhu JW, Lu ZF, Xue D. Local Artemis dysfunction may be one molecular mechanism for androgenetic alopecia via telomere shortening. Med Hypotheses 2012; 79:554. [PMID: 22850665 DOI: 10.1016/j.mehy.2012.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 07/10/2012] [Indexed: 11/24/2022]
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18
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Sengerová B, Allerston CK, Abu M, Lee SY, Hartley J, Kiakos K, Schofield CJ, Hartley JA, Gileadi O, McHugh PJ. Characterization of the human SNM1A and SNM1B/Apollo DNA repair exonucleases. J Biol Chem 2012; 287:26254-67. [PMID: 22692201 PMCID: PMC3406710 DOI: 10.1074/jbc.m112.367243] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Human SNM1A and SNM1B/Apollo have both been implicated in the repair of DNA interstrand cross-links (ICLs) by cellular studies, and SNM1B is also required for telomere protection. Here, we describe studies on the biochemical characterization of the SNM1A and SNM1B proteins. The results reveal some fundamental differences in the mechanisms of the two proteins. Both SNM1A and SNM1B digest double-stranded and single-stranded DNA with a 5'-to-3' directionality in a reaction that is stimulated by divalent cations, and both nucleases are inhibited by the zinc chelator o-phenanthroline. We find that SNM1A has greater affinity for single-stranded DNA over double-stranded DNA that is not observed with SNM1B. Although both proteins demonstrate a low level of processivity on low molecular weight DNA oligonucleotide substrates, when presented with high molecular weight DNA, SNM1A alone is rendered much more active, being capable of digesting kilobase-long stretches of DNA. Both proteins can digest past ICLs induced by the non-distorting minor groove cross-linking agent SJG-136, albeit with SNM1A showing a greater capacity to achieve this. This is consistent with the proposal that SNM1A and SNM1B might exhibit some redundancy in ICL repair. Together, our work establishes differences in the substrate selectivities of SNM1A and SNM1B that are likely to be relevant to their in vivo roles and which might be exploited in the development of selective inhibitors.
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Affiliation(s)
- Blanka Sengerová
- Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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19
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Wu XJ, Zhu JW, Liu H, Lu ZF, Zheng M. Expression and location of phospho-Artemis (Serine516) in hair follicles during induced growth of mouse hair. Arch Dermatol Res 2012; 304:319-24. [PMID: 22476261 DOI: 10.1007/s00403-012-1233-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/06/2012] [Accepted: 03/12/2012] [Indexed: 12/13/2022]
Abstract
Artemis has been implicated in having a role in NHEJ, and it is also a multifunctional protein. Previous studies have found Omenn syndrome-like phenotype due to Artemis mutations and associated with alopecia. As Artemis phosphorylation in its c-terminus including Serine516 is prerequisite for the Artemis endonuclease reaction, we postulate that Artemis (Serine516) may be expressed in hair follicle and relate to hair cycling. In this study, hair growth in C57BL/6 mice was induced by plucking the telogen hair on the back. Expression of Artemis (Serine516) in hair follicles during the hair growth cycle was evaluated by immunofluorescence using cryosections and a specific polyclonal anti-Artemis (Serine516) immunoglobulin G (IgG) antibody. It was detected in germ cells, cap, and club hair adjoining the epidermis in telogen. In anagen II, intense staining for Artemis (Serine516) was found in the whole interfollicular epidermis, and in strand keratinocytes. In anagen IV, intense staining for Artemis (Serine516) was detected in basal cells and upper of outer root sheath (ORS) and inner root sheath (IRS). But only upper ORS and lower medulla were stained positive in anagen VI. Upper ORS and lower cortex were positively stained with Artemis (Serine516) in catagen. Based on the phenomenon that the expression of Artemis (Serine516) in mid-anagen and mature anagen was stronger than that in telogen and catagen, we suggest it may take roles in induced growth of mouse hair.
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Affiliation(s)
- Xian-Jie Wu
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
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20
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Yan Y, Zhang X, Legerski RJ. Artemis interacts with the Cul4A-DDB1DDB2 ubiquitin E3 ligase and regulates degradation of the CDK inhibitor p27. Cell Cycle 2011; 10:4098-109. [PMID: 22134138 DOI: 10.4161/cc.10.23.18227] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Artemis, a member of the SNM1 gene family, is a multifunctional phospho-protein that has been shown to have important roles in V(D)J recombination, DNA double strand break repair, and stress-induced cell-cycle checkpoint regulation. We show here that Artemis interacts with the Cul4A-DDB1 E3 ubiquitin ligase via a direct interaction with the substrate-specificity receptor DDB2. Furthermore, Artemis also interacts with the CDK inhibitor and tumor suppressor p27, a substrate of the Cul4A-DDB1 ligase, and both DDB2 and Artemis are required for the degradation of p27 mediated by this complex. We also show that the regulation of p27 by Artemis and DDB2 is important for cell cycle progression in normally proliferating cells and in response to serum deprivation. These findings thus define a function for Artemis as an effector of Cullin-based E3 ligase-mediated ubiquitylation, demonstrate a novel pathway for the regulation of p27, and show that Cul4A-DDB1(DDB2-Artemis) regulates G1 phase cell cycle progression in mammalian cells.
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Affiliation(s)
- Yiyi Yan
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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21
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Mason JM, Sekiguchi JM. Snm1B/Apollo functions in the Fanconi anemia pathway in response to DNA interstrand crosslinks. Hum Mol Genet 2011; 20:2549-59. [PMID: 21478198 DOI: 10.1093/hmg/ddr153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Fanconi anemia (FA) is an inherited chromosomal instability disorder characterized by childhood aplastic anemia, developmental abnormalities and cancer predisposition. One of the hallmark phenotypes of FA is cellular hypersensitivity to agents that induce DNA interstrand crosslinks (ICLs), such as mitomycin C (MMC). FA is caused by mutation in at least 14 genes which function in the resolution of ICLs during replication. The FA proteins act within the context of a protein network in coordination with multiple repair factors that function in distinct pathways. SNM1B/Apollo is a member of metallo-β-lactamase/βCASP family of nucleases and has been demonstrated to function in ICL repair. However, the relationship between SNM1B and the FA protein network is not known. In the current study, we establish that SNM1B functions epistatically to the central FA factor, FANCD2, in cellular survival after ICL damage and homology-directed repair of DNA double-strand breaks. We also demonstrate that MMC-induced chromosomal anomalies are increased in SNM1B-depleted cells, and this phenotype is not further exacerbated upon depletion of either FANCD2 or another key FA protein, FANCI. Furthermore, we find that SNM1B is required for proper localization of critical repair factors, including FANCD2, BRCA1 and RAD51, to MMC-induced subnuclear foci. Our findings demonstrate that SNM1B functions within the FA pathway during the repair of ICL damage.
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Affiliation(s)
- Jennifer M Mason
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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