1
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Liang F, Rai R, Sodeinde T, Chang S. TRF2-RAP1 represses RAD51-dependent homology-directed telomere repair by promoting BLM-mediated D-loop unwinding and inhibiting BLM-DNA2-dependent 5'-end resection. Nucleic Acids Res 2024; 52:9695-9709. [PMID: 39082275 PMCID: PMC11381343 DOI: 10.1093/nar/gkae642] [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: 05/07/2024] [Revised: 06/26/2024] [Accepted: 07/12/2024] [Indexed: 09/10/2024] Open
Abstract
Inappropriate homology-directed repair (HDR) of telomeres results in catastrophic telomere loss and aberrant chromosome fusions, leading to genome instability. We have previously shown that the TRF2-RAP1 heterodimer protects telomeres from engaging in aberrant telomere HDR. Cells lacking the basic domain of TRF2 and functional RAP1 display HDR-mediated telomere clustering, resulting in the formation of ultrabright telomeres (UTs) and massive chromosome fusions. Using purified proteins, we uncover three distinct molecular pathways that the TRF2-RAP1 heterodimer utilizes to protect telomeres from engaging in aberrant HDR. We show mechanistically that TRF2-RAP1 inhibits RAD51-initiated telomeric D-loop formation. Both the TRF2 basic domain and RAP1-binding to TRF2 are required to block RAD51-mediated homology search. TRF2 recruits the BLM helicase to telomeres through its TRFH domain to promote BLM-mediated unwinding of telomere D-loops. In addition, TRF2-RAP1 inhibits BLM-DNA2-mediated 5' telomere end resection, preventing the generation of 3' single-stranded telomere overhangs necessary for RAD51-dependent HDR. Importantly, cells expressing BLM mutants unable to interact with TRF2 accumulate telomere D-loops and UTs. Our findings uncover distinct molecular mechanisms coordinated by TRF2-RAP1 to protect telomeres from engaging in aberrant HDR.
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Affiliation(s)
- Fengshan Liang
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
| | - Rekha Rai
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
| | - Tori Sodeinde
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
| | - Sandy Chang
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
- Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
- Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
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2
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Hu H, Yan HL, Nguyen THD. Structural biology of shelterin and telomeric chromatin: the pieces and an unfinished puzzle. Biochem Soc Trans 2024; 52:1551-1564. [PMID: 39109533 DOI: 10.1042/bst20230300] [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: 06/14/2024] [Revised: 07/19/2024] [Accepted: 07/25/2024] [Indexed: 08/29/2024]
Abstract
The six-subunit shelterin complex binds to mammalian telomeres and protects them from triggering multiple DNA damage response pathways. The loss of this protective function by shelterin can have detrimental effects on cells. In this review, we first discuss structural studies of shelterin, detailing the contributions of each subunit and inter-subunit interactions in protecting chromosome ends. We then examine the influence of telomeric chromatin dynamics on the function of shelterin at telomeres. These studies provide valuable insights and underscore the challenges that future research must tackle to attain high-resolution structures of shelterin.
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Affiliation(s)
- Hongmiao Hu
- MRC Laboratory of Molecular Biology, Cambridge, U.K
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3
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Brankiewicz-Kopcinska W, Kallingal A, Krzemieniecki R, Baginski M. Targeting shelterin proteins for cancer therapy. Drug Discov Today 2024; 29:104056. [PMID: 38844065 DOI: 10.1016/j.drudis.2024.104056] [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: 03/19/2024] [Revised: 05/17/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024]
Abstract
As a global health challenge, cancer prompts continuous exploration for innovative therapies that are also based on new targets. One promising avenue is targeting the shelterin protein complex, a safeguard for telomeres crucial in preventing DNA damage. The role of shelterin in modulating ataxia-telangiectasia mutated (ATM) and ataxia-telangiectasia and Rad3-related (ATR) kinases, key players in the DNA damage response (DDR), establishes its significance in cancer cells. Disrupting these defence mechanisms of shelterins, especially in cancer cells, renders telomeres vulnerable, potentially leading to genomic instability and hindering cancer cell survival. In this review, we outline recent approaches exploring shelterins as potential anticancer targets, highlighting the prospect of developing selective molecules to exploit telomere vulnerabilities toward new innovative cancer treatments.
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Affiliation(s)
- Wioletta Brankiewicz-Kopcinska
- Department of Pharmaceutical Technology and Biochemistry, Gdansk University of Technology, G. Narutowicza St 11/12, 80-233 Gdansk, Poland; Department of Medical Genetics, Institute of Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway.
| | - Anoop Kallingal
- Department of Pharmaceutical Technology and Biochemistry, Gdansk University of Technology, G. Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Radoslaw Krzemieniecki
- Department of Pharmaceutical Technology and Biochemistry, Gdansk University of Technology, G. Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Maciej Baginski
- Department of Pharmaceutical Technology and Biochemistry, Gdansk University of Technology, G. Narutowicza St 11/12, 80-233 Gdansk, Poland.
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4
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Wu Z, Gu X, Zha L, Yang Q, Zhou Y, Zeng Z. Structural and functional insights into yeast Tbf1 as an atypical telomeric repeat-binding factor. Structure 2024; 32:889-898.e3. [PMID: 38677290 DOI: 10.1016/j.str.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/14/2024] [Accepted: 04/02/2024] [Indexed: 04/29/2024]
Abstract
Telomeric repeat-binding factor 1 (Tbf1) has a similar architecture as the TRF family of telomeric proteins and plays important roles in both telomere homeostasis and ribosome regulation. However, the molecular basis of why Tbf1 has such different functions compared to other TRFs remains unclear. Here, we present the crystal structures of the TRF homology (TRFH) and Myb-L domains from Schizosaccharomyces pombe Tbf1 (spTbf1). TRFH-mediated homodimerization is essential for spTbf1 stability. Importantly, spTbf1TRFH lacks the conserved docking motif for interactions with telomeric proteins, explaining why spTbf1 does not participate in the assembly of the shelterin complex. Finally, structural and biochemical analyses demonstrate that TRFH and Myb-L domains as well as the loop region of spTbf1 coordinate to recognize S. pombe telomeric double-stranded DNA. Overall, our findings provide structural and functional insights into how fungi Tbf1 acts as an atypical telomeric repeat-binding factor, which helps to understand the evolution of TRFH-containing telomeric proteins.
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Affiliation(s)
- Zhenfang Wu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
| | - Xin Gu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin Zha
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Qingqiu Yang
- Department of Hematology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Yuanze Zhou
- Department of Hematology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China.
| | - Zhixiong Zeng
- Hunan Provincial Key Laboratory of the TCM Agricultural Biogenomics, Changsha Medical University, Changsha 410219, China.
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5
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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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6
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Zhao X, Vogirala VK, Liu M, Zhou Y, Rhodes D, Sandin S, Yan J. Exploring TRF2-Dependent DNA Distortion Through Single-DNA Manipulation Studies. Commun Biol 2024; 7:148. [PMID: 38310140 PMCID: PMC10838314 DOI: 10.1038/s42003-024-05838-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/20/2024] [Indexed: 02/05/2024] Open
Abstract
TRF2 is a component of shelterin, a telomere-specific protein complex that protects the ends of mammalian chromosomes from DNA damage signaling and improper repair. TRF2 functions as a homodimer and its interaction with telomeric DNA has been studied, but its full-length DNA-binding properties are unknown. This study examines TRF2's interaction with single-DNA strands and focuses on the conformation of the TRF2-DNA complex and TRF2's preference for DNA chirality. The results show that TRF2-DNA can switch between extended and compact conformations, indicating multiple DNA-binding modes, and TRF2's binding does not have a strong preference for DNA supercoiling chirality when DNA is under low tension. Instead, TRF2 induces DNA bending under tension. Furthermore, both the N-terminal domain of TRF2 and the Myb domain enhance its affinity for the telomere sequence, highlighting the crucial role of multivalent DNA binding in enhancing its affinity and specificity for telomere sequence. These discoveries offer unique insights into TRF2's interaction with telomeric DNA.
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Affiliation(s)
- Xiaodan Zhao
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore
| | - Vinod Kumar Vogirala
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Meihan Liu
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Yu Zhou
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Daniela Rhodes
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Sara Sandin
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore.
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore.
- Umeå university, KBC-huset (KB), Linnaeus väg 10, Umeå, 90187, Sweden.
| | - Jie Yan
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore.
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore.
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
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7
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Rai R, Sodeinde T, Boston A, Chang S. Telomeres cooperate with the nuclear envelope to maintain genome stability. Bioessays 2024; 46:e2300184. [PMID: 38047499 DOI: 10.1002/bies.202300184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/05/2023]
Abstract
Mammalian telomeres have evolved safeguards to prevent their recognition as DNA double-stranded breaks by suppressing the activation of various DNA sensing and repair proteins. We have shown that the telomere-binding proteins TRF2 and RAP1 cooperate to prevent telomeres from undergoing aberrant homology-directed recombination by mediating t-loop protection. Our recent findings also suggest that mammalian telomere-binding proteins interact with the nuclear envelope to maintain chromosome stability. RAP1 interacts with nuclear lamins through KU70/KU80, and disruption of RAP1 and TRF2 function result in nuclear envelope rupture, promoting telomere-telomere recombination to form structures termed ultrabright telomeres. In this review, we discuss the importance of the interactions between shelterin components and the nuclear envelope to maintain telomere homeostasis and genome stability.
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Affiliation(s)
- Rekha Rai
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Tori Sodeinde
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ava Boston
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sandy Chang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, USA
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8
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Sobinoff AP, Di Maro S, Low RRJ, Benedetti R, Tomassi S, D'Aniello A, Russo R, Baglivo I, Chianese U, Pedone PV, Chambery A, Cesare AJ, Altucci L, Pickett HA, Cosconati S. Irreversible inhibition of TRF2 TRFH recruiting functions by a covalent cyclic peptide induces telomeric replication stress in cancer cells. Cell Chem Biol 2023; 30:1652-1665.e6. [PMID: 38065101 DOI: 10.1016/j.chembiol.2023.11.008] [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: 07/25/2022] [Revised: 09/28/2023] [Accepted: 11/13/2023] [Indexed: 12/24/2023]
Abstract
The TRF2 shelterin component is an essential regulator of telomere homeostasis and genomic stability. Mutations in the TRF2TRFH domain physically impair t-loop formation and prevent the recruitment of several factors that promote efficient telomere replication, causing telomeric DNA damage. Here, we design, synthesize, and biologically test covalent cyclic peptides that irreversibly target the TRF2TRFH domain. We identify APOD53 as our most promising compound, as it consistently induces a telomeric DNA damage response in cancer cell lines. APOD53 forms a covalent adduct with a reactive cysteine residue present in the TRF2TRFH domain and induces phenotypes consistent with TRF2TRFH domain mutants. These include induction of a telomeric DNA damage response, increased telomeric replication stress, and impaired recruitment of RTEL1 and SLX4 to telomeres. We demonstrate that APOD53 impairs cancer cell growth and find that co-treatment with APOD53 can exacerbate telomere replication stress caused by the G4 stabilizer RHPS4 and low dose aphidicolin (APH).
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Affiliation(s)
- Alexander P Sobinoff
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Salvatore Di Maro
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ronnie R J Low
- Genome Integrity Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Rosaria Benedetti
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy; Azienda Ospedaliera Universitaria "Luigi Vanvitelli", Medical Epigenetics Program
| | - Stefano Tomassi
- Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131 Naples, Italy
| | - Antonia D'Aniello
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Rosita Russo
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ilaria Baglivo
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ugo Chianese
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy
| | - Paolo V Pedone
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Angela Chambery
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Anthony J Cesare
- Genome Integrity Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Lucia Altucci
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy; BIOGEM, 83031 Ariano Irpino, Italy; Azienda Ospedaliera Universitaria "Luigi Vanvitelli", Medical Epigenetics Program; IEOS CNR, Napoli, Italy
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia.
| | - Sandro Cosconati
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy.
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9
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Brankiewicz W, Kalathiya U, Padariya M, Węgrzyn K, Prusinowski M, Zebrowska J, Zylicz-Stachula A, Skowron P, Drab M, Szajewski M, Ciesielski M, Gawrońska M, Kallingal A, Makowski M, Bagiński M. Modified Peptide Molecules As Potential Modulators of Shelterin Protein Functions; TRF1. Chemistry 2023; 29:e202300970. [PMID: 37332024 DOI: 10.1002/chem.202300970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
In this work, we present studies on relatively new and still not well-explored potential anticancer targets which are shelterin proteins, in particular the TRF1 protein can be blocked by in silico designed "peptidomimetic" molecules. TRF1 interacts directly with the TIN2 protein, and this protein-protein interaction is crucial for the proper functioning of telomere, which could be blocked by our novel modified peptide molecules. Our chemotherapeutic approach is based on assumption that modulation of TRF1-TIN2 interaction may be more harmful for cancer cells as cancer telomeres are more fragile than in normal cells. We have shown in vitro within SPR experiments that our modified peptide PEP1 molecule interacts with TRF1, presumably at the site originally occupied by the TIN2 protein. Disturbance of the shelterin complex by studied molecule may not in short term lead to cytotoxic effects, however blocking TRF1-TIN2 resulted in cellular senescence in cellular breast cancer lines used as a cancer model. Thus, our compounds appeared useful as starting model compounds for precise blockage of TRF proteins.
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Affiliation(s)
- Wioletta Brankiewicz
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233, Gdansk, Poland
| | - Umesh Kalathiya
- International Centre for Cancer Vaccine Science, University of Gdansk, ul. Kładki 24, 80-822, Gdańsk, Poland
| | - Monikaben Padariya
- International Centre for Cancer Vaccine Science, University of Gdansk, ul. Kładki 24, 80-822, Gdańsk, Poland
| | - Katarzyna Węgrzyn
- Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Maciej Prusinowski
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Joanna Zebrowska
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | | | - Piotr Skowron
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Marek Drab
- Unit of Nanostructural Bio-Interactions, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 12 Weigla-Street, 53-114, Wrocław, Poland
| | - Mariusz Szajewski
- Department of Oncological Surgery, Gdynia Oncology Centre, Gdynia, Poland
- Division of Propaedeutics of Oncology, Medical University of Gdańsk, Gdańsk, Poland
| | - Maciej Ciesielski
- Department of Oncological Surgery, Gdynia Oncology Centre, Gdynia, Poland
- Division of Propaedeutics of Oncology, Medical University of Gdańsk, Gdańsk, Poland
| | - Małgorzata Gawrońska
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Anoop Kallingal
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233, Gdansk, Poland
| | - Mariusz Makowski
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland
| | - Maciej Bagiński
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233, Gdansk, Poland
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10
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Sharma T, Kundu N, Kaur S, Shankaraswamy J, Saxena S. Why to target G-quadruplexes using peptides: Next-generation G4-interacting ligands. J Pept Sci 2023; 29:e3491. [PMID: 37009771 DOI: 10.1002/psc.3491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/04/2023]
Abstract
Guanine-rich oligonucleotides existing in both DNA and RNA are able to fold into four-stranded DNA secondary structures via Hoogsteen type hydrogen-bonding, where four guanines self-assemble into a square planar arrangement, which, when stacked upon each other, results in the formation of higher-order structures called G-quadruplexes. Their distribution is not random; they are more frequently present at telomeres, proto-oncogenic promoters, introns, 5'- and 3'-untranslated regions, stem cell markers, ribosome binding sites and so forth and are associated with various biological functions, all of which play a pivotal role in various incurable diseases like cancer and cellular ageing. Several studies have suggested that G-quadruplexes could not regulate biological processes by themselves; instead, various proteins take part in this regulation and can be important therapeutic targets. There are certain limitations in using whole G4-protein for therapeutics purpose because of its high manufacturing cost, laborious structure prediction, dynamic nature, unavailability for oral administration due to its degradation in the gut and inefficient penetration to reach the target site because of the large size. Hence, biologically active peptides can be the potential candidates for therapeutic intervention instead of the whole G4-protein complex. In this review, we aimed to clarify the biological roles of G4s, how we can identify them throughout the genome via bioinformatics, the proteins interacting with G4s and how G4-interacting peptide molecules may be the potential next-generation ligands for targeting the G4 motifs located in biologically important regions.
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Affiliation(s)
- Taniya Sharma
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Nikita Kundu
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Sarvpreet Kaur
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Jadala Shankaraswamy
- Department of Fruit Science, College of Horticulture, Mojerla, Sri Konda Laxman Telangana State Horticultural University, Budwel, Telangana, India
| | - Sarika Saxena
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
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11
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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: 7] [Impact Index Per Article: 7.0] [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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12
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Liu M, Pan H, Kaur P, Wang LJ, Jin M, Detwiler AC, Opresko PL, Tao YJ, Wang H, Riehn R. Assembly path dependence of telomeric DNA compaction by TRF1, TIN2, and SA1. Biophys J 2023; 122:1822-1832. [PMID: 37081787 PMCID: PMC10209029 DOI: 10.1016/j.bpj.2023.04.014] [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: 09/28/2022] [Revised: 03/10/2023] [Accepted: 04/12/2023] [Indexed: 04/22/2023] Open
Abstract
Telomeres, complexes of DNA and proteins, protect ends of linear chromosomes. In humans, the two shelterin proteins TRF1 and TIN2, along with cohesin subunit SA1, were proposed to mediate telomere cohesion. Although the ability of the TRF1-TIN2 and TRF1-SA1 systems to compact telomeric DNA by DNA-DNA bridging has been reported, the function of the full ternary TRF1-TIN2-SA1 system has not been explored in detail. Here, we quantify the compaction of nanochannel-stretched DNA by the ternary system, as well as its constituents, and obtain estimates of the relative impact of its constituents and their interactions. We find that TRF1, TIN2, and SA1 work synergistically to cause a compaction of the DNA substrate, and that maximal compaction occurs if all three proteins are present. By altering the sequence with which DNA substrates are exposed to proteins, we establish that compaction by TRF1 and TIN2 can proceed through binding of TRF1 to DNA, followed by compaction as TIN2 recognizes the previously bound TRF1. We further establish that SA1 alone can also lead to a compaction, and that compaction in a combined system of all three proteins can be understood as an additive effect of TRF1-TIN2 and SA1-based compaction. Atomic force microscopy of intermolecular aggregation confirms that a combination of TRF1, TIN2, and SA1 together drive strong intermolecular aggregation as it would be required during chromosome cohesion.
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Affiliation(s)
- Ming Liu
- Department of Physics, NC State University, Raleigh, North Carolina
| | - Hai Pan
- Department of Physics, NC State University, Raleigh, North Carolina
| | - Parminder Kaur
- Department of Physics, NC State University, Raleigh, North Carolina
| | - Lucia J Wang
- Department of Physics, NC State University, Raleigh, North Carolina
| | - Miao Jin
- Department of BioSciences, Rice University, Houston, Texas
| | - Ariana C Detwiler
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yizhi Jane Tao
- Department of BioSciences, Rice University, Houston, Texas
| | - Hong Wang
- Department of Physics, NC State University, Raleigh, North Carolina
| | - Robert Riehn
- Department of Physics, NC State University, Raleigh, North Carolina.
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13
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Wang S, Xu Z, Li M, Lv M, Shen S, Shi Y, Li F. Structural insights into the recognition of telomeric variant repeat TTGGGG by broad-complex, tramtrack and bric-à-brac - zinc finger protein ZBTB10. J Biol Chem 2023; 299:102918. [PMID: 36657642 PMCID: PMC9958480 DOI: 10.1016/j.jbc.2023.102918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
Multiple proteins bind to telomeric DNA and are important for the role of telomeres in genome stability. A recent study established a broad-complex, tramtrack and bric-à-brac - zinc finger (BTB-ZF) protein, ZBTB10 (zinc finger and BTB domain-containing protein 10), as a telomeric variant repeat-binding protein at telomeres that use an alternative method for lengthening telomeres). ZBTB10 specifically interacts with the double-stranded telomeric variant repeat sequence TTGGGG by employing its tandem C2H2 zinc fingers (ZF1-2). Here, we solved the crystal structure of human ZBTB10 ZF1-2 in complex with a double-stranded DNA duplex containing the sequence TTGGGG to assess the molecular details of this interaction. Combined with calorimetric analysis, we identified the vital residues in TTGGGG recognition and determined the specific recognition mechanisms that are different from those of TZAP (telomere zinc finger-associated protein), a recently defined telomeric DNA-binding protein. Following these studies, we further identified a single amino-acid mutant (Arg767Gln) of ZBTB10 ZF1-2 that shows a preference for the telomeric DNA repeat TTAGGG sequence. We solved the cocrystal structure, providing a structural basis for telomeric DNA recognition by C2H2 ZF proteins.
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Affiliation(s)
- Suman Wang
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Ziyan Xu
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Meili Li
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Mengqi Lv
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Siyuan Shen
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Yunyu Shi
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
| | - Fudong Li
- MOE Key Laboratory for Cellular Dynamics, The School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
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14
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Storchova R, Palek M, Palkova N, Veverka P, Brom T, Hofr C, Macurek L. Phosphorylation of TRF2 promotes its interaction with TIN2 and regulates DNA damage response at telomeres. Nucleic Acids Res 2023; 51:1154-1172. [PMID: 36651296 PMCID: PMC9943673 DOI: 10.1093/nar/gkac1269] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/25/2022] [Accepted: 12/23/2022] [Indexed: 01/19/2023] Open
Abstract
Protein phosphatase magnesium-dependent 1 delta (PPM1D) terminates the cell cycle checkpoint by dephosphorylating the tumour suppressor protein p53. By targeting additional substrates at chromatin, PPM1D contributes to the control of DNA damage response and DNA repair. Using proximity biotinylation followed by proteomic analysis, we identified a novel interaction between PPM1D and the shelterin complex that protects telomeric DNA. In addition, confocal microscopy revealed that endogenous PPM1D localises at telomeres. Further, we found that ATR phosphorylated TRF2 at S410 after induction of DNA double strand breaks at telomeres and this modification increased after inhibition or loss of PPM1D. TRF2 phosphorylation stimulated its interaction with TIN2 both in vitro and at telomeres. Conversely, induced expression of PPM1D impaired localisation of TIN2 and TPP1 at telomeres. Finally, recruitment of the DNA repair factor 53BP1 to the telomeric breaks was strongly reduced after inhibition of PPM1D and was rescued by the expression of TRF2-S410A mutant. Our results suggest that TRF2 phosphorylation promotes the association of TIN2 within the shelterin complex and regulates DNA repair at telomeres.
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Affiliation(s)
- Radka Storchova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Matous Palek
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Natalie Palkova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Pavel Veverka
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Tomas Brom
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Ctirad Hofr
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Libor Macurek
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
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15
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Telomere Status of Advanced Non-Small-Cell Lung Cancer Offers a Novel Promising Prognostic and Predictive Biomarker. Cancers (Basel) 2022; 15:cancers15010290. [PMID: 36612286 PMCID: PMC9818321 DOI: 10.3390/cancers15010290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 01/04/2023] Open
Abstract
Telomere length appears to correlate with survival in early non-small-cell lung cancer (NSCLC), but the prognostic impact of telomere status in advanced NSCLC remains undetermined. Our purpose was to evaluate telomere parameters as prognostic and predictive biomarkers in advanced NSCLC. In 79 biopsies obtained before treatment, we analyzed the telomere length and expression of TERT and shelterin complex genes (TRF1, TRF2, POT1, TPP1, RAP1, and TIN2), using quantitative PCR. Non-responders to first-line chemotherapy were characterized by shorter telomeres and low RAP1 expression (p = 0.0035 and p = 0.0069), and tended to show higher TERT levels (p = 0.058). In multivariate analysis, short telomeres were associated with reduced event-free (EFS, p = 0.0023) and overall survival (OS, p = 0.00041). TERT and TRF2 overexpression correlated with poor EFS (p = 0.0069 and p = 0.00041) and OS (p = 0.0051 and p = 0.007). Low RAP1 and TIN2 expression-levels were linked to reduced EFS (p = 0.00032 and p = 0.0069) and OS (p = 0.000051 and p = 0.02). Short telomeres were also associated with decreased survival after nivolumab therapy (p = 0.097). Evaluation of telomere status in advanced NSCLC emerges as a useful biomarker that allows for the selection of patient groups with different clinical evolutions, to establish personalized treatment.
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16
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Abstract
Shelterin is a multiprotein complex that plays central roles in telomere biology. Mutations in shelterin result in premature aging diseases and familial cancer predisposition. Mechanistic understanding of these so-called telomereopathies is hampered by our lack of knowledge regarding the structure and stoichiometry of shelterin. Here, we use multiple methods to probe the stoichiometry and conformational states of shelterin and reveal that it forms a fully dimeric complex with extensive conformational heterogeneity. Our results highlight the dynamic nature of this essential complex and explain why its high-resolution structure determination has yet to be achieved. Human shelterin is a six-subunit complex—composed of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1—that binds telomeres, protects them from the DNA-damage response, and regulates the maintenance of telomeric DNA. Although high-resolution structures have been generated of the individual structured domains within shelterin, the architecture and stoichiometry of the full complex are currently unknown. Here, we report the purification of shelterin subcomplexes and reconstitution of the entire complex using full-length, recombinant subunits. By combining negative-stain electron microscopy (EM), cross-linking mass spectrometry (XLMS), AlphaFold modeling, mass photometry, and native mass spectrometry (MS), we obtain stoichiometries as well as domain-scale architectures of shelterin subcomplexes and determine that they feature extensive conformational heterogeneity. For POT1/TPP1 and POT1/TPP1/TIN2, we observe high variability in the positioning of the POT1 DNA-binding domain, the TPP1 oligonucleotide/oligosaccharide–binding (OB) fold, and the TIN2 TRFH domain with respect to the C-terminal domains of POT1. Truncation of unstructured linker regions in TIN2, TPP1, and POT1 did not reduce the conformational variability of the heterotrimer. Shelterin and TRF1-containing subcomplexes form fully dimeric stoichiometries, even in the absence of DNA substrates. Shelterin and its subcomplexes showed extensive conformational variability, regardless of the presence of DNA substrates. We conclude that shelterin adopts a multitude of conformations and argue that its unusual architectural variability is beneficial for its many functions at telomeres.
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17
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Sun H, Wu Z, Zhou Y, Lu Y, Lu H, Chen H, Shi S, Zeng Z, Wu J, Lei M. Structural insights into Pot1-ssDNA, Pot1-Tpz1 and Tpz1-Ccq1 Interactions within fission yeast shelterin complex. PLoS Genet 2022; 18:e1010308. [PMID: 35849625 PMCID: PMC9333443 DOI: 10.1371/journal.pgen.1010308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/28/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022] Open
Abstract
The conserved shelterin complex caps chromosome ends to protect telomeres and regulate telomere replication. In fission yeast Schizosaccharomyces pombe, shelterin consists of telomeric single- and double-stranded DNA-binding modules Pot1-Tpz1 and Taz1-Rap1 connected by Poz1, and a specific component Ccq1. While individual structures of the two DNA-binding OB folds of Pot1 (Pot1OB1-GGTTAC and Pot1OB2-GGTTACGGT) are available, structural insight into recognition of telomeric repeats with spacers by the complete DNA-binding domain (Pot1DBD) remains an open question. Moreover, structural information about the Tpz1-Ccq1 interaction requires to be revealed for understanding how the specific component Ccq1 of S. pombe shelterin is recruited to telomeres to function as an interacting hub. Here, we report the crystal structures of Pot1DBD-single-stranded-DNA, Pot1372-555-Tpz1185-212 and Tpz1425-470-Ccq1123-439 complexes and propose an integrated model depicting the assembly mechanism of the shelterin complex at telomeres. The structure of Pot1DBD-DNA unveils how Pot1 recognizes S. pombe degenerate telomeric sequences. Our analyses of Tpz1-Ccq1 reveal structural basis for the essential role of the Tpz1-Ccq1 interaction in telomere recruitment of Ccq1 that is required for telomere maintenance and telomeric heterochromatin formation. Overall, our findings provide valuable structural information regarding interactions within fission yeast shelterin complex at 3’ ss telomeric overhang. Telomeres, composed of repetitive DNA sequences and specialized proteins, are protective structures at the ends of linear chromosomes. The telomere structure is essential for the maintenance of genome integrity and stability, and telomere dysfunction has been linked to human development, aging, cancer and a variety of degenerative diseases. An evolutionarily conserved multiple-protein complex called shelterin plays versatile roles in telomere homeostasis regulation, end protection and heterochromatin establishment. However, the highly flexible nature of shelterin complex has greatly impeded our structural and functional understanding for this important complex. In fission yeast, structures of the shelterin dsDNA-binding protein subcomplex Taz1-Rap1 and the bridge subcomplex Tpz1-Poz1-Rap1 are available. Although individual OB-fold subdomains structures have been characterized, structural information about the complete Pot1DBD bound to telomeric repeats with spacers remains to be revealed. Here, by determining the crystal structures of the telomeric overhang binding Pot1DBD-ssDNA, Pot1372-555-Tpz1185-212 and Tpz1425-470-Ccq1123-439 subcomplexes, we provide structural basis not only for the recognition of S. pombe degenerate telomeric sequences by Pot1, but also for the essential function of the Tpz1-Ccq1 interaction in Ccq1 recruitment to telomeres for telomere maintenance and telomeric heterochromatin formation. These findings provide an integrated model depicting the assembly mechanism of the shelterin complex at telomeres and its multiple roles in telomere biology.
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Affiliation(s)
- Hong Sun
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Zhenfang Wu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Yuanze Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yanjia Lu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Huaisheng Lu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Hongwen Chen
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Shaohua Shi
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Zhixiong Zeng
- Shandong Provincial Key Laboratory of Microbial Engineering, College of Bioengineering, Qilu University of Technology, Shandong, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Jian Wu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Ming Lei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
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18
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Smith EW, Lattmann S, Liu ZB, Ahsan B, Rhodes D. Insights into POT1 structural dynamics revealed by cryo-EM. PLoS One 2022; 17:e0264073. [PMID: 35176105 PMCID: PMC8853558 DOI: 10.1371/journal.pone.0264073] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/02/2022] [Indexed: 12/13/2022] Open
Abstract
Telomeres are protein-DNA complexes that protect the ends of linear eukaryotic chromosomes. Mammalian telomeric DNA consists of 5′-(TTAGGG)n-3′ double-stranded repeats, followed by up to several hundred bases of a 3′ single-stranded G-rich overhang. The G-rich overhang is bound by the shelterin component POT1 which interacts with TPP1, the component involved in telomerase recruitment. A previously published crystal structure of the POT1 N-terminal half bound to the high affinity telomeric ligand 5′-TTAGGGTTAG-3′ showed that the first six nucleotides, TTAGGG, are bound by the OB1 fold, while the adjacent OB2 binds the last four, TTAG. Here, we report two cryo-EM structures of full-length POT1 bound by the POT1-binding domain of TPP1. The structures differ in the relative orientation of the POT1 OB1 and OB2, suggesting that these two DNA-binding OB folds take up alternative conformations. Supporting DNA binding studies using telomeric ligands in which the OB1 and OB2 binding sites were spaced apart, show that POT1 binds with similar affinities to spaced or contiguous binding sites, suggesting plasticity in DNA binding and a role for the alternative conformations observed. A likely explanation is that the structural flexibility of POT1 enhances binding to the tandemly arranged telomeric repeats and hence increases telomere protection.
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Affiliation(s)
- Emmanuel W. Smith
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
| | - Simon Lattmann
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
| | - Zhehui Barry Liu
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
| | - Bilal Ahsan
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
| | - Daniela Rhodes
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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19
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Telomerase in Cancer: Function, Regulation, and Clinical Translation. Cancers (Basel) 2022; 14:cancers14030808. [PMID: 35159075 PMCID: PMC8834434 DOI: 10.3390/cancers14030808] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/29/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Cells undergoing malignant transformation must circumvent replicative senescence and eventual cell death associated with progressive telomere shortening that occurs through successive cell division. To do so, malignant cells reactivate telomerase to extend their telomeres and achieve cellular immortality, which is a “Hallmark of Cancer”. Here we review the telomere-dependent and -independent functions of telomerase in cancer, as well as its potential as a biomarker and therapeutic target to diagnose and treat cancer patients. Abstract During the process of malignant transformation, cells undergo a series of genetic, epigenetic, and phenotypic alterations, including the acquisition and propagation of genomic aberrations that impart survival and proliferative advantages. These changes are mediated in part by the induction of replicative immortality that is accompanied by active telomere elongation. Indeed, telomeres undergo dynamic changes to their lengths and higher-order structures throughout tumor formation and progression, processes overseen in most cancers by telomerase. Telomerase is a multimeric enzyme whose function is exquisitely regulated through diverse transcriptional, post-transcriptional, and post-translational mechanisms to facilitate telomere extension. In turn, telomerase function depends not only on its core components, but also on a suite of binding partners, transcription factors, and intra- and extracellular signaling effectors. Additionally, telomerase exhibits telomere-independent regulation of cancer cell growth by participating directly in cellular metabolism, signal transduction, and the regulation of gene expression in ways that are critical for tumorigenesis. In this review, we summarize the complex mechanisms underlying telomere maintenance, with a particular focus on both the telomeric and extratelomeric functions of telomerase. We also explore the clinical utility of telomeres and telomerase in the diagnosis, prognosis, and development of targeted therapies for primary, metastatic, and recurrent cancers.
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20
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Wu HY, Zheng Y, Laciak AR, Huang NN, Koszelak-Rosenblum M, Flint AJ, Carr G, Zhu G. Structure and Function of SNM1 Family Nucleases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1414:1-26. [PMID: 35708844 DOI: 10.1007/5584_2022_724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Three human nucleases, SNM1A, SNM1B/Apollo, and SNM1C/Artemis, belong to the SNM1 gene family. These nucleases are involved in various cellular functions, including homologous recombination, nonhomologous end-joining, cell cycle regulation, and telomere maintenance. These three proteins share a similar catalytic domain, which is characterized as a fused metallo-β-lactamase and a CPSF-Artemis-SNM1-PSO2 domain. SNM1A and SNM1B/Apollo are exonucleases, whereas SNM1C/Artemis is an endonuclease. This review contains a summary of recent research on SNM1's cellular and biochemical functions, as well as structural biology studies. In addition, protein structure prediction by the artificial intelligence program AlphaFold provides a different view of the proteins' non-catalytic domain features, which may be used in combination with current results from X-ray crystallography and cryo-EM to understand their mechanism more clearly.
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21
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Kaur P, Barnes R, Pan H, Detwiler AC, Liu M, Mahn C, Hall J, Messenger Z, You C, Piehler J, Smart R, Riehn R, Opresko PL, Wang H. TIN2 is an architectural protein that facilitates TRF2-mediated trans- and cis-interactions on telomeric DNA. Nucleic Acids Res 2021; 49:13000-13018. [PMID: 34883513 PMCID: PMC8682769 DOI: 10.1093/nar/gkab1142] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/08/2021] [Indexed: 12/23/2022] Open
Abstract
The telomere specific shelterin complex, which includes TRF1, TRF2, RAP1, TIN2, TPP1 and POT1, prevents spurious recognition of telomeres as double-strand DNA breaks and regulates telomerase and DNA repair activities at telomeres. TIN2 is a key component of the shelterin complex that directly interacts with TRF1, TRF2 and TPP1. In vivo, the large majority of TRF1 and TRF2 are in complex with TIN2 but without TPP1 and POT1. Since knockdown of TIN2 also removes TRF1 and TRF2 from telomeres, previous cell-based assays only provide information on downstream effects after the loss of TRF1/TRF2 and TIN2. Here, we investigated DNA structures promoted by TRF2-TIN2 using single-molecule imaging platforms, including tracking of compaction of long mouse telomeric DNA using fluorescence imaging, atomic force microscopy (AFM) imaging of protein-DNA structures, and monitoring of DNA-DNA and DNA-RNA bridging using the DNA tightrope assay. These techniques enabled us to uncover previously unknown unique activities of TIN2. TIN2S and TIN2L isoforms facilitate TRF2-mediated telomeric DNA compaction (cis-interactions), dsDNA-dsDNA, dsDNA-ssDNA and dsDNA-ssRNA bridging (trans-interactions). Furthermore, TIN2 facilitates TRF2-mediated T-loop formation. We propose a molecular model in which TIN2 functions as an architectural protein to promote TRF2-mediated trans and cis higher-order nucleic acid structures at telomeres.
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Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
| | - Ryan Barnes
- Department of Environmental and Occupational Health, University of Pittsburgh, UPMC Hillman Cancer Center, PA 15213, USA
| | - Hai Pan
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
| | - Ariana C Detwiler
- Department of Environmental and Occupational Health, University of Pittsburgh, UPMC Hillman Cancer Center, PA 15213, USA
| | - Ming Liu
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
| | - Chelsea Mahn
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
| | - Jonathan Hall
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
- Toxicology Program, North Carolina State University, Raleigh, NC27695, USA
| | - Zach Messenger
- Toxicology Program, North Carolina State University, Raleigh, NC27695, USA
| | - Changjiang You
- Department of Biology/Chemistry, Universität Osnabrück, Osnabrück 49076, Germany
| | - Jacob Piehler
- Department of Biology/Chemistry, Universität Osnabrück, Osnabrück 49076, Germany
| | - Robert C Smart
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
- Toxicology Program, North Carolina State University, Raleigh, NC27695, USA
| | - Robert Riehn
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh, UPMC Hillman Cancer Center, PA 15213, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, NC27695, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
- Toxicology Program, North Carolina State University, Raleigh, NC27695, USA
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22
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Telomeres and Cancer. Life (Basel) 2021; 11:life11121405. [PMID: 34947936 PMCID: PMC8704776 DOI: 10.3390/life11121405] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 12/18/2022] Open
Abstract
Telomeres cap the ends of eukaryotic chromosomes and are indispensable chromatin structures for genome protection and replication. Telomere length maintenance has been attributed to several functional modulators, including telomerase, the shelterin complex, and the CST complex, synergizing with DNA replication, repair, and the RNA metabolism pathway components. As dysfunctional telomere maintenance and telomerase activation are associated with several human diseases, including cancer, the molecular mechanisms behind telomere length regulation and protection need particular emphasis. Cancer cells exhibit telomerase activation, enabling replicative immortality. Telomerase reverse transcriptase (TERT) activation is involved in cancer development through diverse activities other than mediating telomere elongation. This review describes the telomere functions, the role of functional modulators, the implications in cancer development, and the future therapeutic opportunities.
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23
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Higa M, Matsuda Y, Fujii J, Sugimoto N, Yoshida K, Fujita M. TRF2-mediated ORC recruitment underlies telomere stability upon DNA replication stress. Nucleic Acids Res 2021; 49:12234-12251. [PMID: 34761263 PMCID: PMC8643664 DOI: 10.1093/nar/gkab1004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Telomeres are intrinsically difficult-to-replicate region of eukaryotic chromosomes. Telomeric repeat binding factor 2 (TRF2) binds to origin recognition complex (ORC) to facilitate the loading of ORC and the replicative helicase MCM complex onto DNA at telomeres. However, the biological significance of the TRF2–ORC interaction for telomere maintenance remains largely elusive. Here, we employed a TRF2 mutant with mutations in two acidic acid residues (E111A and E112A) that inhibited the TRF2–ORC interaction in human cells. The TRF2 mutant was impaired in ORC recruitment to telomeres and showed increased replication stress-associated telomeric DNA damage and telomere instability. Furthermore, overexpression of an ORC1 fragment (amino acids 244–511), which competitively inhibited the TRF2–ORC interaction, increased telomeric DNA damage under replication stress conditions. Taken together, these findings suggest that TRF2-mediated ORC recruitment contributes to the suppression of telomere instability.
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Affiliation(s)
- Mitsunori Higa
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yukihiro Matsuda
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Jumpei Fujii
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Nozomi Sugimoto
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kazumasa Yoshida
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masatoshi Fujita
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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24
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Myler LR, Kinzig CG, Sasi NK, Zakusilo G, Cai SW, de Lange T. The evolution of metazoan shelterin. Genes Dev 2021; 35:1625-1641. [PMID: 34764137 PMCID: PMC8653790 DOI: 10.1101/gad.348835.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/05/2021] [Indexed: 12/11/2022]
Abstract
In this study, Myler et al. investigated the evolutionary origins of shelterin complex, which is comprised of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1; blocks the DNA damage response at chromosome ends; and interacts with telomerase and the CST complex to regulate telomere length. They describe the evolution of metazoan shelterin, showing that TRF1 emerged in vertebrates upon duplication of a TRF2-like ancestor, and providing insights into the biology of shelterin and its evolution from ancestral telomeric DNA-binding proteins. The mammalian telomeric shelterin complex—comprised of TRF1, TRF2, Rap1, TIN2, TPP1, and POT1—blocks the DNA damage response at chromosome ends and interacts with telomerase and the CST complex to regulate telomere length. The evolutionary origins of shelterin are unclear, partly because unicellular organisms have distinct telomeric proteins. Here, we describe the evolution of metazoan shelterin, showing that TRF1 emerged in vertebrates upon duplication of a TRF2-like ancestor. TRF1 and TRF2 diverged rapidly during vertebrate evolution through the acquisition of new domains and interacting factors. Vertebrate shelterin is also distinguished by the presence of an HJRL domain in the split C-terminal OB fold of POT1, whereas invertebrate POT1s carry inserts of variable nature. Importantly, the data reveal that, apart from the primate and rodent POT1 orthologs, all metazoan POT1s are predicted to have a fourth OB fold at their N termini. Therefore, we propose that POT1 arose from a four-OB-fold ancestor, most likely an RPA70-like protein. This analysis provides insights into the biology of shelterin and its evolution from ancestral telomeric DNA-binding proteins.
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Affiliation(s)
- Logan R Myler
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Charles G Kinzig
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Nanda K Sasi
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - George Zakusilo
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Sarah W Cai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10021, USA
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25
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Analysis of telomere length variation and Shelterin complex subunit gene expression changes in ethanol-exposed human embryonic stem cells. J Psychiatr Res 2021; 143:543-549. [PMID: 33243459 PMCID: PMC8126580 DOI: 10.1016/j.jpsychires.2020.11.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 11/04/2020] [Accepted: 11/12/2020] [Indexed: 01/19/2023]
Abstract
Telomeres protect chromosome ends from degradation. Telomere length (TL) can be altered by aging and environmental stress. Shortened TL has been observed in peripheral blood leukocytes of alcohol dependent subjects and ethanol-exposed somatic cells. To understand the impact of ethanol on telomeres in pluripotent stem cells, we investigated the influence of ethanol on TL and the expression of six Shelterin complex subunit or telomere-regulating genes (POT1, RAP1, TIN2, TPP1, TRF1, and TRF2) in human embryonic stem cells (hESCs), which were exposed to 0, 25, 50, or 100 mM of ethanol for 3, 7, or 14 days. Ethanol-induced TL and Shelterin complex subunit gene expression changes were examined by quantitative polymerase chain reactions. Two-way ANOVA tests indicated that TL variation and expression changes of four associated Shelterin complex subunit genes (POT1, TPP1, TIN2, and TRF2) were mainly dependent on the length of ethanol exposure, while TRF1 and RAP1expression was influenced by ethanol concentration, exposure time, and the interaction of ethanol concentration and exposure time. Tukey's multiple comparison tests showed that TL and the expression of POT1, RAP1, TIN2, TPP1, and TRF1 were decreased after a 7-day (versus a 3-day) ethanol exposure. However, the decreased expression of all six Shelterin complex subunit genes was recovered and TL was not further shortened after a 14-day (versus a 7-day) ethanol exposure, likely due to the adaptation of hESCs to ethanol-induced stress. Our study provided further evidence that TL is regulated and maintained by telomere-regulating genes in stem cells under ethanol stress.
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26
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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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27
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Imran SAM, Yazid MD, Cui W, Lokanathan Y. The Intra- and Extra-Telomeric Role of TRF2 in the DNA Damage Response. Int J Mol Sci 2021; 22:ijms22189900. [PMID: 34576063 PMCID: PMC8470803 DOI: 10.3390/ijms22189900] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/12/2022] Open
Abstract
Telomere repeat binding factor 2 (TRF2) has a well-known function at the telomeres, which acts to protect the telomere end from being recognized as a DNA break or from unwanted recombination. This protection mechanism prevents DNA instability from mutation and subsequent severe diseases caused by the changes in DNA, such as cancer. Since TRF2 actively inhibits the DNA damage response factors from recognizing the telomere end as a DNA break, many more studies have also shown its interactions outside of the telomeres. However, very little has been discovered on the mechanisms involved in these interactions. This review aims to discuss the known function of TRF2 and its interaction with the DNA damage response (DDR) factors at both telomeric and non-telomeric regions. In this review, we will summarize recent progress and findings on the interactions between TRF2 and DDR factors at telomeres and outside of telomeres.
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Affiliation(s)
- Siti A. M. Imran
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia; (S.A.M.I.); (M.D.Y.)
| | - Muhammad Dain Yazid
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia; (S.A.M.I.); (M.D.Y.)
| | - Wei Cui
- Institute of Reproductive and Developmental Biology, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK;
| | - Yogeswaran Lokanathan
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia; (S.A.M.I.); (M.D.Y.)
- Correspondence: ; Tel.: +603-9145-7704
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28
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Pan H, Kaur P, Barnes R, Detwiler AC, Sanford SL, Liu M, Xu P, Mahn C, Tang Q, Hao P, Bhattaram D, You C, Gu X, Lu W, Piehler J, Xu G, Weninger K, Riehn R, Opresko PL, Wang H. Structure, dynamics, and regulation of TRF1-TIN2-mediated trans- and cis-interactions on telomeric DNA. J Biol Chem 2021; 297:101080. [PMID: 34403696 PMCID: PMC8437784 DOI: 10.1016/j.jbc.2021.101080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/30/2021] [Accepted: 08/12/2021] [Indexed: 01/17/2023] Open
Abstract
TIN2 is a core component of the shelterin complex linking double-stranded telomeric DNA-binding proteins (TRF1 and TRF2) and single-strand overhang-binding proteins (TPP1-POT1). In vivo, the large majority of TRF1 and TRF2 exist in complexes containing TIN2 but lacking TPP1/POT1; however, the role of TRF1-TIN2 interactions in mediating interactions with telomeric DNA is unclear. Here, we investigated DNA molecular structures promoted by TRF1-TIN2 interaction using atomic force microscopy (AFM), total internal reflection fluorescence microscopy (TIRFM), and the DNA tightrope assay. We demonstrate that the short (TIN2S) and long (TIN2L) isoforms of TIN2 facilitate TRF1-mediated DNA compaction (cis-interactions) and DNA-DNA bridging (trans-interactions) in a telomeric sequence- and length-dependent manner. On the short telomeric DNA substrate (six TTAGGG repeats), the majority of TRF1-mediated telomeric DNA-DNA bridging events are transient with a lifetime of ~1.95 s. On longer DNA substrates (270 TTAGGG repeats), TIN2 forms multiprotein complexes with TRF1 and stabilizes TRF1-mediated DNA-DNA bridging events that last on the order of minutes. Preincubation of TRF1 with its regulator protein Tankyrase 1 and the cofactor NAD+ significantly reduced TRF1-TIN2 mediated DNA-DNA bridging, whereas TIN2 protected the disassembly of TRF1-TIN2 mediated DNA-DNA bridging upon Tankyrase 1 addition. Furthermore, we showed that TPP1 inhibits TRF1-TIN2L-mediated DNA-DNA bridging. Our study, together with previous findings, supports a molecular model in which protein assemblies at telomeres are heterogeneous with distinct subcomplexes and full shelterin complexes playing distinct roles in telomere protection and elongation.
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Affiliation(s)
- Hai Pan
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Ryan Barnes
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ariana C Detwiler
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Samantha Lynn Sanford
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ming Liu
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Pengning Xu
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Chelsea Mahn
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Qingyu Tang
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Pengyu Hao
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Dhruv Bhattaram
- Department of Biomedical Engineering, Georgia Institute of Technology & Emory University of Medicine, Atlanta, Georgia, USA
| | - Changjiang You
- Department of Biology/Chemistry, Universität Osnabrück, Osnabrück, Germany
| | - Xinyun Gu
- College of Art and Sciences, New York University, New York City, New York, USA
| | - Warren Lu
- Department of Pathology at NYU Grossman School of Medicine, New York University, New York City, New York, USA
| | - Jacob Piehler
- Department of Biology/Chemistry, Universität Osnabrück, Osnabrück, Germany
| | - Guozhou Xu
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Keith Weninger
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Robert Riehn
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Molecular Biophysics and Structural Biology Graduate Program, Carnegie Mellon University and the University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA; Toxicology Program, North Carolina State University, Raleigh, North Carolina, USA.
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29
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Multifunctionality of the Telomere-Capping Shelterin Complex Explained by Variations in Its Protein Composition. Cells 2021; 10:cells10071753. [PMID: 34359923 PMCID: PMC8305809 DOI: 10.3390/cells10071753] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/03/2021] [Accepted: 07/09/2021] [Indexed: 12/31/2022] Open
Abstract
Protecting telomere from the DNA damage response is essential to avoid the entry into cellular senescence and organismal aging. The progressive telomere DNA shortening in dividing somatic cells, programmed during development, leads to critically short telomeres that trigger replicative senescence and thereby contribute to aging. In several organisms, including mammals, telomeres are protected by a protein complex named Shelterin that counteract at various levels the DNA damage response at chromosome ends through the specific function of each of its subunits. The changes in Shelterin structure and function during development and aging is thus an intense area of research. Here, we review our knowledge on the existence of several Shelterin subcomplexes and the functional independence between them. This leads us to discuss the possibility that the multifunctionality of the Shelterin complex is determined by the formation of different subcomplexes whose composition may change during aging.
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30
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Li B. Keeping Balance Between Genetic Stability and Plasticity at the Telomere and Subtelomere of Trypanosoma brucei. Front Cell Dev Biol 2021; 9:699639. [PMID: 34291053 PMCID: PMC8287324 DOI: 10.3389/fcell.2021.699639] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
Telomeres, the nucleoprotein complexes at chromosome ends, are well-known for their essential roles in genome integrity and chromosome stability. Yet, telomeres and subtelomeres are frequently less stable than chromosome internal regions. Many subtelomeric genes are important for responding to environmental cues, and subtelomeric instability can facilitate organismal adaptation to extracellular changes, which is a common theme in a number of microbial pathogens. In this review, I will focus on the delicate and important balance between stability and plasticity at telomeres and subtelomeres of a kinetoplastid parasite, Trypanosoma brucei, which causes human African trypanosomiasis and undergoes antigenic variation to evade the host immune response. I will summarize the current understanding about T. brucei telomere protein complex, the telomeric transcript, and telomeric R-loops, focusing on their roles in maintaining telomere and subtelomere stability and integrity. The similarities and differences in functions and underlying mechanisms of T. brucei telomere factors will be compared with those in human and yeast cells.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, Cleveland, OH, United States.,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States.,Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States.,Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, United States
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31
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Habib I, Khan S, Mohammad T, Hussain A, Alajmi MF, Rehman T, Anjum F, Hassan MI. Impact of non-synonymous mutations on the structure and function of telomeric repeat binding factor 1. J Biomol Struct Dyn 2021; 40:9053-9066. [PMID: 33982644 DOI: 10.1080/07391102.2021.1922313] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Telomeric repeat binding factor 1 (TRF1) is one of the major components of the shelterin complex. It directly binds to the telomere and controls its function by regulating the telomerase acting on it. Several variations are reported in the TRF1 gene; some are associated with variety of diseases. Here, we have studied the structural and functional significance of these variations in the TRFH domain of TRF1. We have used cutting-edge computational methods such as SIFT, PolyPhen-2, PROVEAN, Mutation Assessor, mCSM, SDM, STRUM, MAESTRO, and DUET to predict the effects of 124 mutations in the TRFH domain of TRF1. Out of 124 mutations, we have identified 12 deleterious mutations with high confidence based on their prediction. To see the impact of the finally selected mutations on the structure and stability of TRF1, all-atom molecular dynamics (MD) simulations on TRF1-Wild type (WT), L79R and P150R mutants for 200 ns were carried out. A significant conformational change in the structure of the P150R mutant was observed. Our integrated computational study provides a comprehensive understanding of structural changes in TRF1 incurred due to the mutations and subsequent function, leading to the progression of many diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Insan Habib
- Department of Computer Science, Jamia Millia Islamia, New Delhi, India
| | - Shama Khan
- Drug Discovery and Development Centre (H3D), University of Cape Town, Rondebosch, South Africa
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed F Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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32
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Sadhukhan R, Ghosh U. PARP1 modulates telomere sister chromatid exchange and telomere length homeostasis by regulating telomere localization of SLX4 in U2OS cells. Life Sci 2021; 277:119556. [PMID: 33945829 DOI: 10.1016/j.lfs.2021.119556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Poly(ADP-ribose) polymerase1 (PARP1) interacts and poly(ADP-ribosyl)ates telomere repeat binding factor 2 (TRF2), which acts as a platform to recruit a large number of proteins at the telomere. Since the discovery of TRF2-SLX4 interaction, SLX4 is becoming the key player in telomere length (TL) maintenance and repair by telomere sister chromatid exchange (T-SCE). Defective TL maintenance pathway results in a spectrum of diseases called telomeropathies like dyskeratosis congenita, aplastic anemia, fanconi anemia, cancer. We aimed to study the role of SLX4 and PARP1 on each other's telomere localization, T-SCE, and TL maintenance in human telomerase-negative osteosarcoma U2OS cells to understand some of the molecular mechanisms of telomere homeostasis. MATERIALS AND METHODS We checked the role of SLX4 and PARP1 on each other's telomere localization by telomere immunofluorescence. We have cloned full-length wild-type and catalytically inactive mutant PARP1 to understand the role of poly(ADP-ribosyl)ation reaction by PARP1 in telomere length homeostasis. TL of U2OS cells was measured by Q-FISH. T-SCE was measured by Telomere-FISH. KEY FINDINGS We observed that SLX4 has no role in the telomere localization of PARP1. However, reduced localization of SLX4 at undamaged and damaged telomere upon PARP1 depletion was reversed by overexpression of exogenous wild-type PARP1 but not by overexpression of catalytically inactive mutant PARP1. PARP1 depletion synergized SLX4 depletion-mediated reduction of T-SCE. Furthermore, SLX4 depletion elongated TL, and combined insufficiency of SLX4 with PARP1 further elongated TL. CONCLUSION So, PARP1 controls SLX4 recruitment at telomere by poly(ADP-ribosyl)ation reaction, thereby regulating SLX4-mediated T-SCE and TL homeostasis.
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Affiliation(s)
- Ratan Sadhukhan
- Department of Biochemistry & Biophysics, University of Kalyani, Kalyani 741235, India
| | - Utpal Ghosh
- Department of Biochemistry & Biophysics, University of Kalyani, Kalyani 741235, India.
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Lue NF. Duplex Telomere-Binding Proteins in Fungi With Canonical Telomere Repeats: New Lessons in the Rapid Evolution of Telomere Proteins. Front Genet 2021; 12:638790. [PMID: 33719348 PMCID: PMC7952879 DOI: 10.3389/fgene.2021.638790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/08/2021] [Indexed: 01/04/2023] Open
Abstract
The telomere protein assemblies in different fungal lineages manifest quite profound structural and functional divergence, implying a high degree of flexibility and adaptability. Previous comparative analyses of fungal telomeres have focused on the role of telomere sequence alterations in promoting the evolution of corresponding proteins, particularly in budding and fission yeast. However, emerging evidence suggests that even in fungi with the canonical 6-bp telomere repeat unit, there are significant remodeling of the telomere assembly. Indeed, a new protein family can be recruited to serve dedicated telomere functions, and then experience subsequent loss in sub-branches of the clade. An especially interesting example is the Tay1 family of proteins, which emerged in fungi prior to the divergence of basidiomycetes from ascomycetes. This relatively recent protein family appears to have acquired its telomere DNA-binding activity through the modification of another Myb-containing protein. Members of the Tay1 family evidently underwent rather dramatic functional diversification, serving, e.g., as transcription factors in fission yeast while acting to promote telomere maintenance in basidiomycetes and some hemi-ascomycetes. Remarkably, despite its distinct structural organization and evolutionary origin, a basidiomycete Tay1 appears to promote telomere replication using the same mechanism as mammalian TRF1, i.e., by recruiting and regulating Blm helicase activity. This apparent example of convergent evolution at the molecular level highlight the ability of telomere proteins to acquire new interaction targets. The remarkable evolutionary history of Tay1 illustrates the power of protein modularity and the facile acquisition of nucleic acid/protein-binding activity to promote telomere flexibility.
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Affiliation(s)
- Neal F Lue
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, New York, NY, United States.,Sandra and Edward Meyer Cancer Center, Weill Medical College of Cornell University, New York, NY, United States
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Lim CJ, Cech TR. Shaping human telomeres: from shelterin and CST complexes to telomeric chromatin organization. Nat Rev Mol Cell Biol 2021; 22:283-298. [PMID: 33564154 DOI: 10.1038/s41580-021-00328-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
The regulation of telomere length in mammals is crucial for chromosome end-capping and thus for maintaining genome stability and cellular lifespan. This process requires coordination between telomeric protein complexes and the ribonucleoprotein telomerase, which extends the telomeric DNA. Telomeric proteins modulate telomere architecture, recruit telomerase to accessible telomeres and orchestrate the conversion of the newly synthesized telomeric single-stranded DNA tail into double-stranded DNA. Dysfunctional telomere maintenance leads to telomere shortening, which causes human diseases including bone marrow failure, premature ageing and cancer. Recent studies provide new insights into telomerase-related interactions (the 'telomere replisome') and reveal new challenges for future telomere structural biology endeavours owing to the dynamic nature of telomere architecture and the great number of structures that telomeres form. In this Review, we discuss recently determined structures of the shelterin and CTC1-STN1-TEN1 (CST) complexes, how they may participate in the regulation of telomere replication and chromosome end-capping, and how disease-causing mutations in their encoding genes may affect specific functions. Major outstanding questions in the field include how all of the telomere components assemble relative to each other and how the switching between different telomere structures is achieved.
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Affiliation(s)
- Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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Grill S, Nandakumar J. Molecular mechanisms of telomere biology disorders. J Biol Chem 2021; 296:100064. [PMID: 33482595 PMCID: PMC7948428 DOI: 10.1074/jbc.rev120.014017] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
Genetic mutations that affect telomerase function or telomere maintenance result in a variety of diseases collectively called telomeropathies. This wide spectrum of disorders, which include dyskeratosis congenita, pulmonary fibrosis, and aplastic anemia, is characterized by severely short telomeres, often resulting in hematopoietic stem cell failure in the most severe cases. Recent work has focused on understanding the molecular basis of these diseases. Mutations in the catalytic TERT and TR subunits of telomerase compromise activity, while others, such as those found in the telomeric protein TPP1, reduce the recruitment of telomerase to the telomere. Mutant telomerase-associated proteins TCAB1 and dyskerin and the telomerase RNA maturation component poly(A)-specific ribonuclease affect the maturation and stability of telomerase. In contrast, disease-associated mutations in either CTC1 or RTEL1 are more broadly associated with telomere replication defects. Yet even with the recent surge in studies decoding the mechanisms underlying these diseases, a significant proportion of dyskeratosis congenita mutations remain uncharacterized or poorly understood. Here we review the current understanding of the molecular basis of telomeropathies and highlight experimental data that illustrate how genetic mutations drive telomere shortening and dysfunction in these patients. This review connects insights from both clinical and molecular studies to create a comprehensive view of the underlying mechanisms that drive these diseases. Through this, we emphasize recent advances in therapeutics and pinpoint disease-associated variants that remain poorly defined in their mechanism of action. Finally, we suggest future avenues of research that will deepen our understanding of telomere biology and telomere-related disease.
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Affiliation(s)
- Sherilyn Grill
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
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Cicconi A, Rai R, Xiong X, Broton C, Al-Hiyasat A, Hu C, Dong S, Sun W, Garbarino J, Bindra RS, Schildkraut C, Chen Y, Chang S. Microcephalin 1/BRIT1-TRF2 interaction promotes telomere replication and repair, linking telomere dysfunction to primary microcephaly. Nat Commun 2020; 11:5861. [PMID: 33203878 PMCID: PMC7672075 DOI: 10.1038/s41467-020-19674-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 10/22/2020] [Indexed: 01/07/2023] Open
Abstract
Telomeres protect chromosome ends from inappropriately activating the DNA damage and repair responses. Primary microcephaly is a key clinical feature of several human telomere disorder syndromes, but how microcephaly is linked to dysfunctional telomeres is not known. Here, we show that the microcephalin 1/BRCT-repeats inhibitor of hTERT (MCPH1/BRIT1) protein, mutated in primary microcephaly, specifically interacts with the TRFH domain of the telomere binding protein TRF2. The crystal structure of the MCPH1-TRF2 complex reveals that this interaction is mediated by the MCPH1 330YRLSP334 motif. TRF2-dependent recruitment of MCPH1 promotes localization of DNA damage factors and homology directed repair of dysfunctional telomeres lacking POT1-TPP1. Additionally, MCPH1 is involved in the replication stress response, promoting telomere replication fork progression and restart of stalled telomere replication forks. Our work uncovers a previously unrecognized role for MCPH1 in promoting telomere replication, providing evidence that telomere replication defects may contribute to the onset of microcephaly.
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Affiliation(s)
- Alessandro Cicconi
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Rekha Rai
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Xuexue Xiong
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Cayla Broton
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.5386.8000000041936877XTri- Institutional MD/PhD Program, Weill Cornell Medical College, New York, NY 10065 USA
| | - Amer Al-Hiyasat
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Chunyi Hu
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Siying Dong
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Wenqi Sun
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Jennifer Garbarino
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Therapeutic Radiology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Ranjit S. Bindra
- grid.47100.320000000419368710Department of Therapeutic Radiology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Experimental Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
| | - Carl Schildkraut
- grid.251993.50000000121791997Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 USA
| | - Yong Chen
- grid.507739.fState Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Sandy Chang
- grid.47100.320000000419368710Department of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA ,grid.47100.320000000419368710Department of Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520 USA
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N-terminal modified cyclopeptidic mimetics of Apollo TBM as inhibitors of TRF2. Bioorg Med Chem Lett 2020; 30:127401. [PMID: 32871539 DOI: 10.1016/j.bmcl.2020.127401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 11/23/2022]
Abstract
Telomeric repeat binding factor 2 (TRF2) plays an important role in protecting telomeres from being recognized as DNA breaks. TRF2 performs its telomere protecting functions partially by recruiting a number of accessory proteins to telomeres through its TRF homology (TFRH) domain. Identification of small molecular compounds which can bind to the TRFH domain of TRF2 and block the interactions between TRF2 and its associated proteins is crucial for elucidating the molecular mechanisms of these protein-protein interactions. Using a previously identified peptidic mimetic of ApolloTBM as a lead compound, we designed and synthesized a series of novel TRF2 inhibitors by non-peptidic modifications of the N-terminal residues. These compounds can maintain the binding affinities to TRF2 but have much reduced peptidic characteristics compared to the lead compound.
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Guo T, Dong Y, Chen Y, Liu L, Sun H. Development and optimization of a cascade of screening assays for inhibitors of TRF2. Anal Biochem 2020; 602:113796. [PMID: 32485162 DOI: 10.1016/j.ab.2020.113796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 11/30/2022]
Abstract
TRF2 is a telomere associated protein which plays an important role in telomere maintenance. Knockdown of TRF2 can cause chromosomal end to end fusions and induce DNA damage responses. TRF2 exerts its functions partially by recruiting a number of accessory proteins through its TRF homology domain (TRFH), therefore identification of small molecular compounds which can bind to the TRFH domain of TRF2 and block the interactions of TRF2 with its associated proteins is important to elucidate the molecular mechanism of these protein-protein interactions. Development of robust and sensitive screening and evaluation assays is critical to the identification of TRF2 inhibitors, in this paper we reported the development and optimization of a cascade of screening and binding affinity evaluation assays, including a competitive FP (Fluorescence Polarization) assay utilized in our previous research, and two novel label-free DSF (Differential Scanning Fluorescence) and BLI (Biolayer Interferometry) assays. A previously identified TRF2 inhibitor TRF2-27 was used as an internal reference compound and evaluated in all of these assays. According to the results, DSF assay is not suitable for TRF2 screening because of the low ΔTm, while the optimized labeled-free BLI assay was demonstrated to be an accurate and reproducible assay for TRF2 inhibitor screening and characterization.
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Affiliation(s)
- Tianyue Guo
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, PR China
| | - Yao Dong
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, PR 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, PR China
| | - Liu Liu
- Pharmablock Sciences (Nanjing), Inc., 10 XueFu Road, Jiangbei New District, Nanjing, 210032, PR China.
| | - Haiying Sun
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, PR China.
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da Cruz I, Brochier-Armanet C, Benavente R. The TERB1-TERB2-MAJIN complex of mouse meiotic telomeres dates back to the common ancestor of metazoans. BMC Evol Biol 2020; 20:55. [PMID: 32408858 PMCID: PMC7227075 DOI: 10.1186/s12862-020-01612-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 04/15/2020] [Indexed: 02/15/2023] Open
Abstract
Background Meiosis is essential for sexual reproduction and generates genetically diverse haploid gametes from a diploid germ cell. Reduction of ploidy depends on active chromosome movements during early meiotic prophase I. Chromosome movements require telomere attachment to the nuclear envelope. This attachment is mediated by telomere adaptor proteins. Telomere adaptor proteins have to date been identified in fission yeast and mice. In the mouse, they form a complex composed of the meiotic proteins TERB1, TERB2, and MAJIN. No sequence similarity was observed between these three mouse proteins and the adaptor proteins of fission yeast, raising the question of the evolutionary history and significance of this specific protein complex. Result Here, we show the TERB1, TERB2, and MAJIN proteins are found throughout the Metazoa and even in early-branching non-bilateral phyla such as Cnidaria, Placozoa and Porifera. Metazoan TERB1, TERB2, and MAJIN showed comparable domain architecture across all clades. Furthermore, the protein domains involved in the formation of the complex as well as those involved for the interaction with the telomere shelterin protein and the LINC complexes revealed high sequence similarity. Finally, gene expression in the cnidarian Hydra vulgaris provided evidence that the TERB1-TERB2-MAJIN complex is selectively expressed in the germ line. Conclusion Our results indicate that the TERB1-TERB2-MAJIN complex has an ancient origin in metazoans, suggesting conservation of meiotic functions.
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Affiliation(s)
- Irene da Cruz
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074, Würzburg, Germany
| | - Céline Brochier-Armanet
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, F-69622, Villeurbanne, France
| | - Ricardo Benavente
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074, Würzburg, Germany.
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Gilbert-Girard S, Gravel A, Collin V, Wight DJ, Kaufer BB, Lazzerini-Denchi E, Flamand L. Role for the shelterin protein TRF2 in human herpesvirus 6A/B chromosomal integration. PLoS Pathog 2020; 16:e1008496. [PMID: 32320442 PMCID: PMC7197865 DOI: 10.1371/journal.ppat.1008496] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 05/04/2020] [Accepted: 03/24/2020] [Indexed: 02/07/2023] Open
Abstract
Human herpesviruses 6A and 6B (HHV-6A/B) are unique among human herpesviruses in their ability to integrate their genome into host chromosomes. Viral integration occurs at the ends of chromosomes within the host telomeres. The ends of the HHV-6A/B genomes contain telomeric repeats that facilitate the integration process. Here, we report that productive infections are associated with a massive increase in telomeric sequences of viral origin. The majority of the viral telomeric signals can be detected within viral replication compartments (VRC) that contain the viral DNA processivity factor p41 and the viral immediate-early 2 (IE2) protein. Components of the shelterin protein complex present at telomeres, including TRF1 and TRF2 are also recruited to VRC during infection. Biochemical, immunofluorescence coupled with in situ hybridization and chromatin immunoprecipitation demonstrated the binding of TRF2 to the HHV-6A/B telomeric repeats. In addition, approximately 60% of the viral IE2 protein localize at cellular telomeres during infection. Transient knockdown of TRF2 resulted in greatly reduced (13%) localization of IE2 at cellular telomeres (p<0.0001). Lastly, TRF2 knockdown reduced HHV-6A/B integration frequency (p<0.05), while no effect was observed on the infection efficiency. Overall, our study identified that HHV-6A/B IE2 localizes to telomeres during infection and highlight the role of TRF2 in HHV-6A/B infection and chromosomal integration.
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Affiliation(s)
- Shella Gilbert-Girard
- Division of Infectious Disease and Immunity, CHU de Québec Research Center, Quebec City, Quebec, Canada
| | - Annie Gravel
- Division of Infectious Disease and Immunity, CHU de Québec Research Center, Quebec City, Quebec, Canada
| | - Vanessa Collin
- Division of Infectious Disease and Immunity, CHU de Québec Research Center, Quebec City, Quebec, Canada
| | - Darren J. Wight
- Institut für Virologie, Freie Universität Berlin, Berlin, Germany
| | | | - Eros Lazzerini-Denchi
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Louis Flamand
- Division of Infectious Disease and Immunity, CHU de Québec Research Center, Quebec City, Quebec, Canada
- Department of microbiology, infectious diseases and immunology, Faculty of Medicine, Université Laval, Quebec City, Québec, Canada
- * E-mail:
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Structural Features of Nucleoprotein CST/Shelterin Complex Involved in the Telomere Maintenance and Its Association with Disease Mutations. Cells 2020; 9:cells9020359. [PMID: 32033110 PMCID: PMC7072152 DOI: 10.3390/cells9020359] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/29/2022] Open
Abstract
Telomere comprises the ends of eukaryotic linear chromosomes and is composed of G-rich (TTAGGG) tandem repeats which play an important role in maintaining genome stability, premature aging and onsets of many diseases. Majority of the telomere are replicated by conventional DNA replication, and only the last bit of the lagging strand is synthesized by telomerase (a reverse transcriptase). In addition to replication, telomere maintenance is principally carried out by two key complexes known as shelterin (TRF1, TRF2, TIN2, RAP1, POT1, and TPP1) and CST (CDC13/CTC1, STN1, and TEN1). Shelterin protects the telomere from DNA damage response (DDR) and regulates telomere length by telomerase; while, CST govern the extension of telomere by telomerase and C strand fill-in synthesis. We have investigated both structural and biochemical features of shelterin and CST complexes to get a clear understanding of their importance in the telomere maintenance. Further, we have analyzed ~115 clinically important mutations in both of the complexes. Association of such mutations with specific cellular fault unveils the importance of shelterin and CST complexes in the maintenance of genome stability. A possibility of targeting shelterin and CST by small molecule inhibitors is further investigated towards the therapeutic management of associated diseases. Overall, this review provides a possible direction to understand the mechanisms of telomere borne diseases, and their therapeutic intervention.
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He H, Li W, Comiskey DF, Liyanarachchi S, Nieminen TT, Wang Y, DeLap KE, Brock P, de la Chapelle A. A Truncating Germline Mutation of TINF2 in Individuals with Thyroid Cancer or Melanoma Results in Longer Telomeres. Thyroid 2020; 30:204-213. [PMID: 31928178 PMCID: PMC7047085 DOI: 10.1089/thy.2019.0156] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background: Our genome sequencing analysis revealed a frameshift mutation in the shelterin gene TINF2 in a large family with individuals affected with papillary thyroid carcinoma (PTC) and melanoma. Here, we further characterized the mutation and screened for coding variants in the 6 shelterin genes in 24 families. Methods: Sanger sequencing was performed to screen for the TINF2 mutation in the key family. Quantitative reverse transcription-polymerase chain reaction (PCR) was used for TINF2 gene expression analysis. Exogenous expression and co-immunoprecipitation techniques were used for assessing TINF2 binding to TERF1. Relative telomere length (RTL) was quantified in DNAs from lymphocytes by using quantitative real-time PCR. Whole exome sequencing (WES) was performed in seven families with individuals affected with PTC and other cancer types. Screening for DNA variants in shelterin genes was performed by using whole genome sequencing data from 17 families and WES data from 7 further families. Results: The TINF2 mutation (TINF2 p.Trp198fs) showed complete co-segregation with PTC and melanoma in the key family. The mutation is not reported in databases and not identified in 23 other families we screened. The expression of TINF2 was borderline reduced in individuals with the mutation. The truncated TINF2 protein showed abolished binding to TERF1. The RTL in the individuals with the mutation was significantly longer when compared with those without the mutation from the same family as well as compared with 62 healthy controls. Among the 24 families, we identified 3 missense and 1 synonymous variant(s) in 2 shelterin genes (TINF2 and ACD). Conclusions: The rare frameshift mutation in the TINF2 gene and the associated longer telomere length suggest that dysregulated telomeres could be a mechanism predisposing to PTC and melanoma. DNA coding variants in shelterin genes are rare. Further studies are required to evaluate the roles of variants in shelterin genes in thyroid cancer and melanoma.
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Affiliation(s)
- Huiling He
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
- Address correspondence to: Huiling He, MD, Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, 895 Biomedical Research Tower, 460 West 12th Avenue, Columbus, OH 43210
| | - Wei Li
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Daniel F. Comiskey
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Sandya Liyanarachchi
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Taina T. Nieminen
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Yanqiang Wang
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Katherine E. DeLap
- Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Pamela Brock
- Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Albert de la Chapelle
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
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Smith EM, Pendlebury DF, Nandakumar J. Structural biology of telomeres and telomerase. Cell Mol Life Sci 2020; 77:61-79. [PMID: 31728577 PMCID: PMC6986361 DOI: 10.1007/s00018-019-03369-x] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 01/16/2023]
Abstract
Telomeres are protein-DNA complexes that protect chromosome ends from illicit ligation and resection. Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA to counter telomere shortening. Human telomeres are composed of complexes between telomeric DNA and a six-protein complex known as shelterin. The shelterin proteins TRF1 and TRF2 provide the binding affinity and specificity for double-stranded telomeric DNA, while the POT1-TPP1 shelterin subcomplex coats the single-stranded telomeric G-rich overhang that is characteristic of all our chromosome ends. By capping chromosome ends, shelterin protects telomeric DNA from unwanted degradation and end-to-end fusion events. Structures of the human shelterin proteins reveal a network of constitutive and context-specific interactions. The shelterin protein-DNA structures reveal the basis for both the high affinity and DNA sequence specificity of these interactions, and explain how shelterin efficiently protects chromosome ends from genome instability. Several protein-protein interactions, many provided by the shelterin component TIN2, are critical for upholding the end-protection function of shelterin. A survey of these protein-protein interfaces within shelterin reveals a series of "domain-peptide" interactions that allow for efficient binding and adaptability towards new functions. While the modular nature of shelterin has facilitated its part-by-part structural characterization, the interdependence of subunits within telomerase has made its structural solution more challenging. However, the exploitation of several homologs in combination with recent advancements in cryo-EM capabilities has led to an exponential increase in our knowledge of the structural biology underlying telomerase function. Telomerase homologs from a wide range of eukaryotes show a typical retroviral reverse transcriptase-like protein core reinforced with elements that deliver telomerase-specific functions including recruitment to telomeres and high telomere-repeat addition processivity. In addition to providing the template for reverse transcription, the RNA component of telomerase provides a scaffold for the catalytic and accessory protein subunits, defines the limits of the telomeric repeat sequence, and plays a critical role in RNP assembly, stability, and trafficking. While a high-resolution definition of the human telomerase structure is only beginning to emerge, the quick pace of technical progress forecasts imminent breakthroughs in this area. Here, we review the structural biology surrounding telomeres and telomerase to provide a molecular description of mammalian chromosome end protection and end replication.
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Affiliation(s)
- Eric M Smith
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Devon F Pendlebury
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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Rai R, Gu P, Broton C, Kumar-Sinha C, Chen Y, Chang S. The Replisome Mediates A-NHEJ Repair of Telomeres Lacking POT1-TPP1 Independently of MRN Function. Cell Rep 2019; 29:3708-3725.e5. [PMID: 31825846 PMCID: PMC7001145 DOI: 10.1016/j.celrep.2019.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 09/22/2019] [Accepted: 11/04/2019] [Indexed: 02/07/2023] Open
Abstract
Telomeres use shelterin to protect chromosome ends from activating the DNA damage sensor MRE11-RAD50-NBS1 (MRN), repressing ataxia-telangiectasia, mutated (ATM) and ATM and Rad3-related (ATR) dependent DNA damage checkpoint responses. The MRE11 nuclease is thought to be essential for the resection of the 5' C-strand to generate the microhomologies necessary for alternative non-homologous end joining (A-NHEJ) repair. In the present study, we uncover DNA damage signaling and repair pathways engaged by components of the replisome complex to repair dysfunctional telomeres. In cells lacking MRN, single-stranded telomeric overhangs devoid of POT1-TPP1 do not recruit replication protein A (RPA), ATR-interacting protein (ATRIP), and RAD 51. Rather, components of the replisome complex, including Claspin, Proliferating cell nuclear antigen (PCNA), and Downstream neighbor of SON (DONSON), initiate DNA-PKcs-mediated p-CHK1 activation and A-NHEJ repair. In addition, Claspin directly interacts with TRF2 and recruits EXO1 to newly replicated telomeres to promote 5' end resection. Our data indicate that MRN is dispensable for the repair of dysfunctional telomeres lacking POT1-TPP1 and highlight the contributions of the replisome in telomere repair.
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Affiliation(s)
- Rekha Rai
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA.
| | - Peili Gu
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA
| | - Cayla Broton
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA; Tri-Institutional MD/PhD Program, Weill Cornell Medical College, New York, NY 10065, USA
| | - Chandan Kumar-Sinha
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Yong Chen
- National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China
| | - Sandy Chang
- Departments of Laboratory Medicine, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA; Department of Pathology, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 330 Cedar St., New Haven, CT 06520, USA.
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45
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Chen Y. The structural biology of the shelterin complex. Biol Chem 2019; 400:457-466. [PMID: 30352022 DOI: 10.1515/hsz-2018-0368] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/15/2018] [Indexed: 02/07/2023]
Abstract
The shelterin complex protects telomeric DNA and plays critical roles in maintaining chromosome stability. The structures and functions of the shelterin complex have been extensively explored in the past decades. This review summarizes the current progress on structural studies of shelterin complexes from different species. It focuses on the structural features and assembly of common structural domains, highlighting the evolutionary plasticity and conserved roles of shelterin proteins in telomere homeostasis and protection.
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Affiliation(s)
- Yong Chen
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, 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.,School of Life Science and Technology, Shanghai Tech University, 100 Haike Road, Shanghai 201210, China
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46
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Guven-Maiorov E, Tsai CJ, Nussinov R. Oncoviruses Can Drive Cancer by Rewiring Signaling Pathways Through Interface Mimicry. Front Oncol 2019; 9:1236. [PMID: 31803618 PMCID: PMC6872517 DOI: 10.3389/fonc.2019.01236] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/28/2019] [Indexed: 01/17/2023] Open
Abstract
Oncoviruses rewire host pathways to subvert host immunity and promote their survival and proliferation. However, exactly how is challenging to understand. Here, by employing the first and to date only interface-based host-microbe interaction (HMI) prediction method, we explore a pivotal strategy oncoviruses use to drive cancer: mimicking binding surfaces-interfaces-of human proteins. We show that oncoviruses can target key human network proteins and transform cells by acquisition of cancer hallmarks. Experimental large-scale mapping of HMIs is difficult and individual HMIs do not permit in-depth grasp of tumorigenic virulence mechanisms. Our computational approach is tractable and 3D structural HMI models can help elucidate pathogenesis mechanisms and facilitate drug design. We observe that many host proteins are unique targets for certain oncoviruses, whereas others are common to several, suggesting similar infectious strategies. A rough estimation of our false discovery rate based on the tissue expression of oncovirus-targeted human proteins is 25%.
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Affiliation(s)
- Emine Guven-Maiorov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
- Department of Human Genetics and Molecular Medicine, Sackler Institute of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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47
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Pike AM, Strong MA, Ouyang JPT, Greider CW. TIN2 Functions with TPP1/POT1 To Stimulate Telomerase Processivity. Mol Cell Biol 2019; 39:e00593-18. [PMID: 31383750 PMCID: PMC6791651 DOI: 10.1128/mcb.00593-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 02/10/2019] [Accepted: 07/30/2019] [Indexed: 12/20/2022] Open
Abstract
TIN2 is an important regulator of telomere length, and mutations in TINF2, the gene encoding TIN2, cause short-telomere syndromes. While the genetics underscore the importance of TIN2, the mechanism through which TIN2 regulates telomere length remains unclear. Here, we tested the effects of human TIN2 on telomerase activity. We identified a new isoform in human cells, TIN2M, that is expressed at levels similar to those of previously studied TIN2 isoforms. All three TIN2 isoforms localized to and maintained telomere integrity in vivo, and localization was not disrupted by telomere syndrome mutations. Using direct telomerase activity assays, we discovered that TIN2 stimulated telomerase processivity in vitro All of the TIN2 isoforms stimulated telomerase to similar extents. Mutations in the TPP1 TEL patch abrogated this stimulation, suggesting that TIN2 functions with TPP1/POT1 to stimulate telomerase processivity. We conclude from our data and previously published work that TIN2/TPP1/POT1 is a functional shelterin subcomplex.
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Affiliation(s)
- Alexandra M Pike
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Margaret A Strong
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John Paul T Ouyang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Biochemistry Cell and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Carol W Greider
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Biochemistry Cell and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Abstract
Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Accumulation of critically short telomeres is proposed to be a primary molecular cause of aging and age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as or telomeropathies. The rate of telomere shortening throughout life is determined by endogenous (genetic) and external (nongenetic) factors. Therapeutic strategies based on telomerase activation are being developed to treat and prevent telomere-associated diseases, namely aging-related diseases and telomeropathies. Here, we review the molecular mechanisms underlying telomere driven diseases with particular emphasis on cardiovascular diseases.
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Affiliation(s)
- Paula Martínez
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
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Duan X, Yang Y, Zhang D, Wang S, Feng X, Wang T, Wang P, Ding M, Zhang H, Liu B, Wei W, Yao W, Cui L, Zhou X, Wang W. Genetic polymorphisms, mRNA expression levels of telomere-binding proteins, and associates with telomere damage in PAHs-Exposure workers. CHEMOSPHERE 2019; 231:442-449. [PMID: 31146136 DOI: 10.1016/j.chemosphere.2019.05.134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 06/09/2023]
Abstract
Coke oven emissions (COEs), confirmed human carcinogens, are mainly composed of polycyclic aromatic hydrocarbons (PAHs). Telomere shortening in blood leukocytes has been associated with COEs, and polymorphisms in metabolic enzymes. However, the relationship between polymorphisms in telomere related genes and telomere shortening in COEs exposed workers has never been evaluated. Therefore, we measured telomere length and mRNA expression levels of telomere-binding proteins (TBPs) by qPCR method in leucocyte from 544 COEs exposed workers and 238 office staffs (referents). Flight mass spectrometry was used to perform the genotyping of selected functional and susceptible SNPs. The results showed that the telomere length in the exposure group 0.75(0.51,1.08) was significantly shorter than that in the control group 1.05(0.76,1.44) (P < 0.001). The mRNA expression levels of TPP1, TERF1 and TERF2 genes in the exposure group were significantly lower than those in the control group (P < 0.05), the mRNA expression level of POT1 in the exposure group was significantly higher than that in the control group (P < 0.05). We used the wild homozygous genotype as a reference, subjects carrying TERT rs2736109 AA, TERT rs3215401 CC and TERT rs2736100 GT + GG genotypes had significantly longer telomere length in the exposure group (P < 0.05). In conclusion, the workers exposed to COEs had shorter telomere length, which was regulated by the TPP1, TERF1, TERF2 and POT1 genes expression levels, and the gene polymorphisms of TERT gene were associated with the telomere length among PAHs-exposure workers.
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Affiliation(s)
- Xiaoran Duan
- Biotherapy Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, Henan, China; Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Yongli Yang
- Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Daping Zhang
- Department of Cardiology, Huaihe Hospital of Henan University, Kaifeng, 475000, Henan, China
| | - Sihua Wang
- Department of Occupational Health, Henan Institute for Occupational Medicine, Zhengzhou, 450052, Henan, China
| | - Xiaolei Feng
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Tuanwei Wang
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Pengpeng Wang
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Mingcui Ding
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Hui Zhang
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Bin Liu
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Wan Wei
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Wu Yao
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Liuxin Cui
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Xiaoshan Zhou
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Wei Wang
- Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China.
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50
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Janovič T, Stojaspal M, Veverka P, Horáková D, Hofr C. Human Telomere Repeat Binding Factor TRF1 Replaces TRF2 Bound to Shelterin Core Hub TIN2 when TPP1 Is Absent. J Mol Biol 2019; 431:3289-3301. [DOI: 10.1016/j.jmb.2019.05.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/17/2022]
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