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Sadr Z, Ghasemi M, Jafarpour S, Seyfi R, Ghasemi A, Boustanipour E, Khorshid HRK, Ehtesham N. Beginning at the ends: telomere and telomere-based cancer therapeutics. Mol Genet Genomics 2024; 300:1. [PMID: 39638969 DOI: 10.1007/s00438-024-02206-6] [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: 07/26/2024] [Accepted: 11/15/2024] [Indexed: 12/07/2024]
Abstract
Telomeres, which are situated at the terminal ends of chromosomes, undergo a reduction in length with each cellular division, ultimately reaching a critical threshold that triggers cellular senescence. Cancer cells circumvent this senescence by utilizing telomere maintenance mechanisms (TMMs) that grant them a form of immortality. These mechanisms can be categorized into two primary processes: the reactivation of telomerase reverse transcriptase and the alternative lengthening of telomeres (ALT) pathway, which is dependent on homologous recombination (HR). Various strategies have been developed to inhibit telomerase activation in 85-95% of cancers, including the use of antisense oligonucleotides such as small interfering RNAs and endogenous microRNAs, agents that simulate telomere uncapping, expression modulators, immunotherapeutic vaccines targeting telomerase, reverse transcriptase inhibitors, stabilization of G-quadruplex structures, and gene therapy approaches. Conversely, in the remaining 5-15% of human cancers that rely on ALT, mechanisms involve modifications in the chromatin environment surrounding telomeres, upregulation of TERRA long non-coding RNA, enhanced activation of the ataxia telangiectasia and Rad-3-related protein kinase signaling pathway, increased interactions with nuclear receptors, telomere repositioning driven by HR, and recombination events between non-sister chromatids, all of which present potential targets for therapeutic intervention. Additionally, combinatorial therapy has emerged as a strategy that employs selective agents to simultaneously target both telomerase and ALT, aiming for optimal clinical outcomes. Given the critical role of anti-TMM strategies in cancer treatment, this review provides an overview of the latest insights into the structure and function of telomeres, their involvement in tumorigenesis, and the advancements in TMM-based cancer therapies.
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Affiliation(s)
- Zahra Sadr
- Department of Medical Genetics, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Masoumeh Ghasemi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Soheyla Jafarpour
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reyhaneh Seyfi
- Department of Stem Cells Technology and Tissue Regeneration, Faculty of Interdisciplinary Science and Technologies, Tarbiat Modares University, Tehran, Iran
| | - Aida Ghasemi
- Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Boustanipour
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Naeim Ehtesham
- Department of Medical Genetics, School of Medicine, Iranshahr University of Medical Sciences, Iranshahr, Iran.
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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 PMCID: PMC7617103 DOI: 10.1042/bst20230300] [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: 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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Pańczyszyn A, Boniewska-Bernacka E, Wertel I, Sadakierska-Chudy A, Goc A. Telomeres and SIRT1 as Biomarkers of Gamete Oxidative Stress, Fertility, and Potential IVF Outcome. Int J Mol Sci 2024; 25:8652. [PMID: 39201341 PMCID: PMC11354255 DOI: 10.3390/ijms25168652] [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: 06/20/2024] [Revised: 08/05/2024] [Accepted: 08/07/2024] [Indexed: 09/02/2024] Open
Abstract
The number of infertile couples undergoing in vitro fertilisation (IVF) has increased significantly. The efficacy of this procedure is contingent upon a multitude of factors, including gamete quality. One factor influencing gamete quality is oxidative stress, which leads to telomere damage and accelerates cellular ageing. Identifying new biomarkers that can predict the success of assisted reproduction techniques is a current relevant area of research. In this review, we discuss the potential role of SIRT1, a protein known to protect against oxidative stress and telomeres, which are responsible for genome stability, as biomarkers of gamete quality and assisted reproduction technique outcomes.
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Affiliation(s)
- Anna Pańczyszyn
- Institute of Medical Sciences, Department of Biology and Genetics, Faculty of Medicine, University of Opole, Oleska 48, 45-052 Opole, Poland; (E.B.-B.); (A.G.)
| | - Ewa Boniewska-Bernacka
- Institute of Medical Sciences, Department of Biology and Genetics, Faculty of Medicine, University of Opole, Oleska 48, 45-052 Opole, Poland; (E.B.-B.); (A.G.)
| | - Iwona Wertel
- Independent Laboratory of Cancer Diagnostics and Immunology, Medical University of Lublin, Chodźki 1, 20-093 Lublin, Poland;
| | - Anna Sadakierska-Chudy
- Department of Genetics, Faculty of Medicine and Health Sciences, Collegium Medicum, Andrzej Frycz Modrzewski Krakow University, Gustawa Herlinga-Grudzinskiego 1, 30-705 Krakow, Poland;
| | - Anna Goc
- Institute of Medical Sciences, Department of Biology and Genetics, Faculty of Medicine, University of Opole, Oleska 48, 45-052 Opole, Poland; (E.B.-B.); (A.G.)
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4
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Khayat F, Alshmery M, Pal M, Oliver A, Bianchi A. Binding of the TRF2 iDDR motif to RAD50 highlights a convergent evolutionary strategy to inactivate MRN at telomeres. Nucleic Acids Res 2024; 52:7704-7719. [PMID: 38884214 PMCID: PMC11260466 DOI: 10.1093/nar/gkae509] [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: 04/04/2023] [Revised: 05/07/2024] [Accepted: 06/07/2024] [Indexed: 06/18/2024] Open
Abstract
Telomeres protect chromosome ends from unscheduled DNA repair, including from the MRN (MRE11, RAD50, NBS1) complex, which processes double-stranded DNA breaks (DSBs) via activation of the ATM kinase, promotes DNA end-tethering aiding the non-homologous end-joining (NHEJ) pathway, and initiates DSB resection through the MRE11 nuclease. A protein motif (MIN, for MRN inhibitor) inhibits MRN at budding yeast telomeres by binding to RAD50 and evolved at least twice, in unrelated telomeric proteins Rif2 and Taz1. We identify the iDDR motif of human shelterin protein TRF2 as a third example of convergent evolution for this telomeric mechanism for binding MRN, despite the iDDR lacking sequence homology to the MIN motif. CtIP is required for activation of MRE11 nuclease action, and we provide evidence for binding of a short C-terminal region of CtIP to a RAD50 interface that partly overlaps with the iDDR binding site, indicating that the interaction is mutually exclusive. In addition, we show that the iDDR impairs the DNA binding activity of RAD50. These results highlight direct inhibition of MRN action as a crucial role of telomeric proteins across organisms and point to multiple mechanisms enforced by the iDDR to disable the many activities of the MRN complex.
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Affiliation(s)
- Freddy Khayat
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Majedh Alshmery
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
- Department of Life Sciences, Hafr Al Batin University, Saudi Arabia
| | - Mohinder Pal
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
- School of Biosciences, University of Kent, Canterbury, UK
| | - Antony W Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Alessandro Bianchi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
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5
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Cai SW, Takai H, Zaug AJ, Dilgen TC, Cech TR, Walz T, de Lange T. POT1 recruits and regulates CST-Polα/primase at human telomeres. Cell 2024; 187:3638-3651.e18. [PMID: 38838667 PMCID: PMC11246235 DOI: 10.1016/j.cell.2024.05.002] [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: 06/12/2023] [Revised: 03/12/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024]
Abstract
Telomere maintenance requires the extension of the G-rich telomeric repeat strand by telomerase and the fill-in synthesis of the C-rich strand by Polα/primase. At telomeres, Polα/primase is bound to Ctc1/Stn1/Ten1 (CST), a single-stranded DNA-binding complex. Like mutations in telomerase, mutations affecting CST-Polα/primase result in pathological telomere shortening and cause a telomere biology disorder, Coats plus (CP). We determined cryogenic electron microscopy structures of human CST bound to the shelterin heterodimer POT1/TPP1 that reveal how CST is recruited to telomeres by POT1. Our findings suggest that POT1 hinge phosphorylation is required for CST recruitment, and the complex is formed through conserved interactions involving several residues mutated in CP. Our structural and biochemical data suggest that phosphorylated POT1 holds CST-Polα/primase in an inactive, autoinhibited state until telomerase has extended the telomere ends. We propose that dephosphorylation of POT1 releases CST-Polα/primase into an active state that completes telomere replication through fill-in synthesis.
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Affiliation(s)
- Sarah W Cai
- Laboratory of Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA; Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065, USA
| | - Hiroyuki Takai
- Laboratory of Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Arthur J Zaug
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80303, USA; BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Teague C Dilgen
- Laboratory of Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80303, USA; BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065, USA.
| | - Titia de Lange
- Laboratory of Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA.
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6
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Alanazi AR, Parkinson GN, Haider S. Structural Motifs at the Telomeres and Their Role in Regulatory Pathways. Biochemistry 2024; 63:827-842. [PMID: 38481135 PMCID: PMC10993422 DOI: 10.1021/acs.biochem.4c00023] [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: 01/11/2024] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 04/04/2024]
Abstract
Telomeres are specialized structures, found at the ends of linear chromosomes in eukaryotic cells, that play a crucial role in maintaining the stability and integrity of genomes. They are composed of repetitive DNA sequences, ssDNA overhangs, and several associated proteins. The length of telomeres is linked to cellular aging in humans, and deficiencies in their maintenance are associated with various diseases. Key structural motifs at the telomeres serve to protect vulnerable chromosomal ends. Telomeric DNA also has the ability to form diverse complex DNA higher-order structures, including T-loops, D-loops, R-loops, G-loops, G-quadruplexes, and i-motifs, in the complementary C-rich strand. While many essential proteins at telomeres have been identified, the intricacies of their interactions and structural details are still not fully understood. This Perspective highlights recent advancements in comprehending the structures associated with human telomeres. It emphasizes the significance of telomeres, explores various telomeric structural motifs, and delves into the structural biology surrounding telomeres and telomerase. Furthermore, telomeric loops, their topologies, and the associated proteins that contribute to the safeguarding of telomeres are discussed.
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Affiliation(s)
- Abeer
F R Alanazi
- UCL
School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Gary N Parkinson
- UCL
School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Shozeb Haider
- UCL
School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
- UCL
Centre for Advanced Research Computing, University College London, London WC1H 9RN, United
Kingdom
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7
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Yin L, Jiang N, Li T, Zhang Y, Yuan S. Telomeric function and regulation during male meiosis in mice and humans. Andrology 2024. [PMID: 38511802 DOI: 10.1111/andr.13631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/26/2024] [Accepted: 03/03/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Telomeres are unique structures situated at the ends of chromosomes. Preserving the structure and function of telomeres is essential for maintaining genomic stability and promoting genetic diversity during male meiosis in mammals. MATERIAL-METHODS This review compiled recent literature on the function and regulation of telomeres during male meiosis in both mice and humans, and also highlighted the critical roles of telomeres in reproductive biology and medicine. RESULTS-DISCUSSION Various structures, consisting of the LINC complex (SUN-KASH), SPDYA-CDK2, TTM trimer (TERB1-TERB2-MAJIN), and shelterin, are critical in controlling telomeric activities, such as nuclear envelope attachment and bouquet formation. Other than telomere-related proteins, cohesins and genes responsible for regulating telomere function are also highlighted, though the exact mechanism remains unclear. The gene-mutant mouse models with meiotic defects directly reveal the essential roles of telomeres in male meiosis. Recently reported mutant genes associated with telomere activity in clinical practice have also been illustrated in detail. CONCLUSIONS Proper regulation of telomere activities is essential for male meiosis progression in mice and humans.
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Affiliation(s)
- Lisha Yin
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Nan Jiang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Youzhi Zhang
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology; Hubei Engineering Research Center of Traditional Chinese Medicine of South Hubei Province, Xianning, China
| | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Laboratory of Animal Center, Huazhong University of Science and Technology, Wuhan, China
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8
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Das A, Giri AK, Bhattacharjee P. Targeting 'histone mark': Advanced approaches in epigenetic regulation of telomere dynamics in cancer. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195007. [PMID: 38237857 DOI: 10.1016/j.bbagrm.2024.195007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/23/2024]
Abstract
Telomere integrity is required for the maintenance of genome stability and prevention of oncogenic transformation of cells. Recent evidence suggests the presence of epigenetic modifications as an important regulator of mammalian telomeres. Telomeric and subtelomeric regions are rich in epigenetic marks that regulate telomere length majorly through DNA methylation and post-translational histone modifications. Specific histone modifying enzymes play an integral role in establishing telomeric histone codes necessary for the maintenance of structural integrity. Alterations of crucial histone moieties and histone modifiers cause deregulations in the telomeric chromatin leading to carcinogenic manifestations. This review delves into the significance of histone modifications and their influence on telomere dynamics concerning cancer. Additionally, it highlights the existing research gaps that hold the potential to drive the development of therapeutic interventions targeting the telomere epigenome.
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Affiliation(s)
- Ankita Das
- Department of Environmental Science, University of Calcutta, Kolkata 700019, India; Department of Zoology, University of Calcutta, Kolkata 700019, India
| | - Ashok K Giri
- Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Pritha Bhattacharjee
- Department of Environmental Science, University of Calcutta, Kolkata 700019, India.
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9
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Cai SW, Takai H, Walz T, de Lange T. POT1 recruits and regulates CST-Polα/Primase at human telomeres. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539880. [PMID: 37215005 PMCID: PMC10197580 DOI: 10.1101/2023.05.08.539880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Telomere maintenance requires extension of the G-rich telomeric repeat strand by telomerase and fill-in synthesis of the C-rich strand by Polα/Primase. Telomeric Polα/Primase is bound to Ctc1-Stn1-Ten1 (CST), a single-stranded DNA-binding complex. Like mutations in telomerase, mutations affecting CST-Polα/Primase result in pathological telomere shortening and cause a telomere biology disorder, Coats plus (CP). We determined cryogenic electron microscopy structures of human CST bound to the shelterin heterodimer POT1/TPP1 that reveal how CST is recruited to telomeres by POT1. Phosphorylation of POT1 is required for CST recruitment, and the complex is formed through conserved interactions involving several residues mutated in CP. Our structural and biochemical data suggest that phosphorylated POT1 holds CST-Polα/Primase in an inactive auto-inhibited state until telomerase has extended the telomere ends. We propose that dephosphorylation of POT1 releases CST-Polα/Primase into an active state that completes telomere replication through fill-in synthesis.
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Affiliation(s)
- Sarah W. Cai
- Laboratory of Cell Biology and Genetics, The Rockefeller University; New York, NY, USA
- Laboratory of Molecular Electron Microscopy, The Rockefeller University; New York, NY, USA
| | - Hiroyuki Takai
- Laboratory of Cell Biology and Genetics, The Rockefeller University; New York, NY, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University; New York, NY, USA
| | - Titia de Lange
- Laboratory of Cell Biology and Genetics, The Rockefeller University; New York, NY, USA
- Lead contact
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10
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Hu H, van Roon AMM, Ghanim GE, Ahsan B, Oluwole AO, Peak-Chew SY, Robinson CV, Nguyen THD. Structural basis of telomeric nucleosome recognition by shelterin factor TRF1. SCIENCE ADVANCES 2023; 9:eadi4148. [PMID: 37624885 PMCID: PMC10456876 DOI: 10.1126/sciadv.adi4148] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023]
Abstract
Shelterin and nucleosomes are the key players that organize mammalian chromosome ends into the protective telomere caps. However, how they interact with each other at telomeres remains unknown. We report cryo-electron microscopy structures of a human telomeric nucleosome both unbound and bound to the shelterin factor TRF1. Our structures reveal that TRF1 binds unwrapped nucleosomal DNA ends by engaging both the nucleosomal DNA and the histone octamer. Unexpectedly, TRF1 binding shifts the register of the nucleosomal DNA by 1 bp. We discovered that phosphorylation of the TRF1 C terminus and a noncanomical DNA binding surface on TRF1 are critical for its association with telomeric nucleosomes. These insights into shelterin-chromatin interactions have crucial implications for understanding telomeric chromatin organization and other roles of shelterin at telomeres including replication and transcription.
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Affiliation(s)
- Hongmiao Hu
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | | | | | - Bilal Ahsan
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Abraham O. Oluwole
- Department of Chemistry, University of Oxford, Oxford, OX1 3QZ UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, OX1 3QU UK
| | | | - Carol V. Robinson
- Department of Chemistry, University of Oxford, Oxford, OX1 3QZ UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, OX1 3QU UK
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11
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Waksal JA, Bruedigam C, Komrokji RS, Jamieson CHM, Mascarenhas JO. Telomerase-targeted therapies in myeloid malignancies. Blood Adv 2023; 7:4302-4314. [PMID: 37216228 PMCID: PMC10424149 DOI: 10.1182/bloodadvances.2023009903] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/08/2023] [Accepted: 05/14/2023] [Indexed: 05/24/2023] Open
Abstract
Human telomeres are tandem arrays that are predominantly composed of 5'-TTAGGG-3' nucleotide sequences at the terminal ends of chromosomes. These sequences serve 2 primary functions: they preserve genomic integrity by protecting the ends of chromosomes, preventing inappropriate degradation by DNA repair mechanisms, and they prevent loss of genetic information during cellular division. When telomeres shorten to reach a critical length, termed the Hayflick limit, cell senescence or death is triggered. Telomerase is a key enzyme involved in synthesizing and maintaining the length of telomeres within rapidly dividing cells and is upregulated across nearly all malignant cells. Accordingly, targeting telomerase to inhibit uncontrolled cell growth has been an area of great interest for decades. In this review, we summarize telomere and telomerase biology because it relates to both physiologic and malignant cells. We discuss the development of telomere- and telomerase-targeted therapeutic candidates within the realm of myeloid malignancies. We overview all mechanisms of targeting telomerase that are currently in development, with a particular focus on imetelstat, an oligonucleotide with direct telomerase inhibitory properties that has advanced the furthest in clinical development and has demonstrated promising data in multiple myeloid malignancies.
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Affiliation(s)
- Julian A. Waksal
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Claudia Bruedigam
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | | | | | - John O. Mascarenhas
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY
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12
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Tesmer VM, Brenner KA, Nandakumar J. Human POT1 protects the telomeric ds-ss DNA junction by capping the 5' end of the chromosome. Science 2023; 381:771-778. [PMID: 37590346 PMCID: PMC10666826 DOI: 10.1126/science.adi2436] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023]
Abstract
Protection of telomeres 1 (POT1) is the 3' single-stranded overhang-binding telomeric protein that prevents an ataxia telangiectasia and Rad3-related (ATR) DNA damage response (DDR) at chromosome ends. What precludes the DDR machinery from accessing the telomeric double-stranded-single-stranded junction is unknown. We demonstrate that human POT1 binds this junction by recognizing the phosphorylated 5' end of the chromosome. High-resolution crystallographic structures reveal that the junction is capped by POT1 through a "POT-hole" surface, the mutation of which compromises junction protection in vitro and telomeric 5'-end definition and DDR suppression in human cells. Whereas both mouse POT1 paralogs bind the single-stranded overhang, POT1a, not POT1b, contains a POT-hole and binds the junction, which explains POT1a's sufficiency for end protection. Our study shifts the paradigm for DDR suppression at telomeres by highlighting the importance of protecting the double-stranded-single-stranded junction.
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Affiliation(s)
- Valerie M. Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Kirsten A. Brenner
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
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13
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Le NT. Metabolic regulation of endothelial senescence. Front Cardiovasc Med 2023; 10:1232681. [PMID: 37649668 PMCID: PMC10464912 DOI: 10.3389/fcvm.2023.1232681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/18/2023] [Indexed: 09/01/2023] Open
Abstract
Endothelial cell (EC) senescence is increasingly recognized as a significant contributor to the development of vascular dysfunction and age-related disorders and diseases, including cancer and cardiovascular diseases (CVD). The regulation of cellular senescence is known to be influenced by cellular metabolism. While extensive research has been conducted on the metabolic regulation of senescence in other cells such as cancer cells and fibroblasts, our understanding of the metabolic regulation of EC senescence remains limited. The specific metabolic changes that drive EC senescence are yet to be fully elucidated. The objective of this review is to provide an overview of the intricate interplay between cellular metabolism and senescence, with a particular emphasis on recent advancements in understanding the metabolic changes preceding cellular senescence. I will summarize the current knowledge on the metabolic regulation of EC senescence, aiming to offer insights into the underlying mechanisms and future research directions.
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Affiliation(s)
- Nhat-Tu Le
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
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14
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Abstract
It has been known for decades that telomerase extends the 3' end of linear eukaryotic chromosomes and dictates the telomeric repeat sequence based on the template in its RNA. However, telomerase does not mitigate sequence loss at the 5' ends of chromosomes, which results from lagging strand DNA synthesis and nucleolytic processing. Therefore, a second enzyme is needed to keep telomeres intact: DNA polymerase α/Primase bound to Ctc1-Stn1-Ten1 (CST). CST-Polα/Primase maintains telomeres through a fill-in reaction that replenishes the lost sequences at the 5' ends. CST not only serves to maintain telomeres but also determines their length by keeping telomerase from overelongating telomeres. Here we discuss recent data on the evolution, structure, function, and recruitment of mammalian CST-Polα/Primase, highlighting the role of this complex and telomere length control in human disease.
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Affiliation(s)
- Sarah W Cai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10065, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10065, USA
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15
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Banerjee P, Rosales JE, Chau K, Nguyen MTH, Kotla S, Lin SH, Deswal A, Dantzer R, Olmsted-Davis EA, Nguyen H, Wang G, Cooke JP, Abe JI, Le NT. Possible molecular mechanisms underlying the development of atherosclerosis in cancer survivors. Front Cardiovasc Med 2023; 10:1186679. [PMID: 37332576 PMCID: PMC10272458 DOI: 10.3389/fcvm.2023.1186679] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023] Open
Abstract
Cancer survivors undergone treatment face an increased risk of developing atherosclerotic cardiovascular disease (CVD), yet the underlying mechanisms remain elusive. Recent studies have revealed that chemotherapy can drive senescent cancer cells to acquire a proliferative phenotype known as senescence-associated stemness (SAS). These SAS cells exhibit enhanced growth and resistance to cancer treatment, thereby contributing to disease progression. Endothelial cell (EC) senescence has been implicated in atherosclerosis and cancer, including among cancer survivors. Treatment modalities for cancer can induce EC senescence, leading to the development of SAS phenotype and subsequent atherosclerosis in cancer survivors. Consequently, targeting senescent ECs displaying the SAS phenotype hold promise as a therapeutic approach for managing atherosclerotic CVD in this population. This review aims to provide a mechanistic understanding of SAS induction in ECs and its contribution to atherosclerosis among cancer survivors. We delve into the mechanisms underlying EC senescence in response to disturbed flow and ionizing radiation, which play pivotal role in atherosclerosis and cancer. Key pathways, including p90RSK/TERF2IP, TGFβR1/SMAD, and BH4 signaling are explored as potential targets for cancer treatment. By comprehending the similarities and distinctions between different types of senescence and the associated pathways, we can pave the way for targeted interventions aim at enhancing the cardiovascular health of this vulnerable population. The insights gained from this review may facilitate the development of novel therapeutic strategies for managing atherosclerotic CVD in cancer survivors.
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Affiliation(s)
- Priyanka Banerjee
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Julia Enterría Rosales
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- School of Medicine, Instituto Tecnológico de Monterrey, Guadalajara, Mexico
| | - Khanh Chau
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Minh T. H. Nguyen
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
- Department of Life Science, University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Sivareddy Kotla
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Steven H. Lin
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Anita Deswal
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Robert Dantzer
- Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Elizabeth A. Olmsted-Davis
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Hung Nguyen
- Cancer Division, Burnett School of Biomedical Science, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Guangyu Wang
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - John P. Cooke
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Jun-ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Nhat-Tu Le
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
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16
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Torres DE, Reckard AT, Klocko AD, Seidl MF. Nuclear genome organization in fungi: from gene folding to Rabl chromosomes. FEMS Microbiol Rev 2023; 47:fuad021. [PMID: 37197899 PMCID: PMC10246852 DOI: 10.1093/femsre/fuad021] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/28/2023] [Accepted: 05/08/2023] [Indexed: 05/19/2023] Open
Abstract
Comparative genomics has recently provided unprecedented insights into the biology and evolution of the fungal lineage. In the postgenomics era, a major research interest focuses now on detailing the functions of fungal genomes, i.e. how genomic information manifests into complex phenotypes. Emerging evidence across diverse eukaryotes has revealed that the organization of DNA within the nucleus is critically important. Here, we discuss the current knowledge on the fungal genome organization, from the association of chromosomes within the nucleus to topological structures at individual genes and the genetic factors required for this hierarchical organization. Chromosome conformation capture followed by high-throughput sequencing (Hi-C) has elucidated how fungal genomes are globally organized in Rabl configuration, in which centromere or telomere bundles are associated with opposite faces of the nuclear envelope. Further, fungal genomes are regionally organized into topologically associated domain-like (TAD-like) chromatin structures. We discuss how chromatin organization impacts the proper function of DNA-templated processes across the fungal genome. Nevertheless, this view is limited to a few fungal taxa given the paucity of fungal Hi-C experiments. We advocate for exploring genome organization across diverse fungal lineages to ensure the future understanding of the impact of nuclear organization on fungal genome function.
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Affiliation(s)
- David E Torres
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Laboratory of Phytopathology, Wageningen University and Research,Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands
| | - Andrew T Reckard
- Department of Chemistry and Biochemistry, University of Colorado Colorado Springs, 234 Centennial Hall, 1420 Austin Bluffs Pkwy, Colorado Springs, CO 80918 USA
| | - Andrew D Klocko
- Department of Chemistry and Biochemistry, University of Colorado Colorado Springs, 234 Centennial Hall, 1420 Austin Bluffs Pkwy, Colorado Springs, CO 80918 USA
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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17
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Harmak H, Redouane S, Charoute H, Aniq Filali O, Barakat A, Rouba H. In silico exploration and molecular dynamics of deleterious SNPs on the human TERF1 protein triggering male infertility. J Biomol Struct Dyn 2023; 41:14665-14688. [PMID: 36995171 DOI: 10.1080/07391102.2023.2193995] [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: 11/15/2022] [Accepted: 02/18/2023] [Indexed: 03/31/2023]
Abstract
By limiting chromosome erosion and end-to-end fusions, telomere integrity is critical for chromosome stability and cell survival. During mitotic cycles or due to environmental stresses, telomeres become progressively shorter and dysfunctional, thus triggering cellular senescence, genomic instability and cell death. To avoid such consequences, the telomerase action, as well as the Shelterin and CST complexes, assure the telomere's protection. Telomeric repeat binding factor 1 (TERF1), which is one of the primary components of the Shelterin complex, binds directly to the telomere and controls its length and function by regulating the telomerase activity. Several reports about TERF1 gene variations have been associated with different diseases, and some of them have linked these variations to male infertility. Hence, this paper can be advantageous to investigate the association between the missense variants of the TERF1 gene and the susceptibility to male infertility. The stepwise prediction of SNPs pathogenicity followed in this study was based on stability and conservation analysis, post-translational modification, secondary structure, functional interaction prediction, binding energy evaluation and finally molecular dynamic simulation. Prediction matching among the tools revealed that out of 18 SNPs, only four (rs1486407144, rs1259659354, rs1257022048 and rs1320180267) were predicted as the most damaging and highly deleterious SNPs affecting the TERF1 protein and its molecular dynamics when interacting with the TERB1 protein by influencing the function, structural stability, flexibility and compaction of the overall complex. Interestingly, these polymorphisms should be considered during genetic screening so they can be used effectively as genetic biomarkers for male infertility diagnosis.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Houda Harmak
- Laboratory of Genomics and Human Genetics, 1, Place Louis Pasteur, Institut Pasteur du Maroc, Casablanca, Morocco
- Laboratory of Physiopathology, Molecular Genetics and Biotechnology, Department of Biology, Faculty of Sciences Ain Chock, Hassan II University, Casablanca, Morocco
| | - Salaheddine Redouane
- Laboratory of Genomics and Human Genetics, 1, Place Louis Pasteur, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Hicham Charoute
- Research Unit of Epidemiology, Biostatistics and Bioinformatics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Ouafaa Aniq Filali
- Laboratory of Physiopathology, Molecular Genetics and Biotechnology, Department of Biology, Faculty of Sciences Ain Chock, Hassan II University, Casablanca, Morocco
| | - Abdelhamid Barakat
- Laboratory of Genomics and Human Genetics, 1, Place Louis Pasteur, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Hassan Rouba
- Laboratory of Genomics and Human Genetics, 1, Place Louis Pasteur, Institut Pasteur du Maroc, Casablanca, Morocco
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Welfer GA, Freudenthal BD. Recent advancements in the structural biology of human telomerase and their implications for improved design of cancer therapeutics. NAR Cancer 2023; 5:zcad010. [PMID: 36879683 PMCID: PMC9984990 DOI: 10.1093/narcan/zcad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/31/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Telomerase is a specialized reverse transcriptase that synthesizes telomeric repeats at the ends of linear chromosomes. Telomerase is transiently expressed in germ and stem cells, but nearly all somatic cells silence it after differentiating. However, the vast majority of cancer cells reactivate and constitutively express telomerase to maintain replicative immortality. Because of this, telomerase has remained a promising broad-spectrum chemotherapeutic target for over 30 years. However, various challenges associated with obtaining high-resolution structural data for telomerase have limited the development of rationally designed structure-based therapeutics. Various techniques and model systems have been utilized to advance our understanding of the structural biology of telomerase. In particular, multiple high-resolution cryogenic electron microscopy (cryo-EM) structures published within the past few years have revealed new components of the telomerase complex with near atomic resolution structural models. Additionally, these structures have provided details for how telomerase is recruited to telomeres and its mechanism of telomere synthesis. With these new pieces of evidence, and the promising outlook for future refinements to our current models, the possibility of telomerase specific chemotherapeutics is becoming more tangible than ever. This review summarizes these recent advancements and outlines outstanding questions in the field.
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Affiliation(s)
- Griffin A Welfer
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
- University of Kansas Cancer Center, Kansas City, KS 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
- University of Kansas Cancer Center, Kansas City, KS 66160, USA
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Soman A, Korolev N, Nordenskiöld L. Telomeric chromatin structure. Curr Opin Struct Biol 2022; 77:102492. [PMID: 36335846 DOI: 10.1016/j.sbi.2022.102492] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 11/06/2022]
Abstract
Eukaryotic DNA is packaged into nucleosomes, which further condenses into chromosomes. The telomeres, which form the protective end-capping of chromosomes, play a pivotal role in ageing and cancer. Recently, significant advances have been made in understanding the nucleosomal and telomeric chromatin structure at the molecular level. In addition, recent studies shed light on the nucleosomal organisation at telomeres revealing its ultrastructural organisation, the atomic structure at the nucleosome level, its dynamic properties, and higher-order packaging of telomeric chromatin. Considerable advances have furthermore been made in understanding the structure, function and organisation of shelterin, telomerase and CST complexes. Here we discuss these recent advances in the organisation of telomeric nucleosomes and chromatin and highlight progress in the structural understanding of shelterin, telomerase and CST complexes.
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Affiliation(s)
- Aghil Soman
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Nikolay Korolev
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore.
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