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Bettin N, Querido E, Gialdini I, Grupelli GP, Goretti E, Cantarelli M, Andolfato M, Soror E, Sontacchi A, Jurikova K, Chartrand P, Cusanelli E. TERRA transcripts localize at long telomeres to regulate telomerase access to chromosome ends. SCIENCE ADVANCES 2024; 10:eadk4387. [PMID: 38865460 PMCID: PMC11168465 DOI: 10.1126/sciadv.adk4387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 05/08/2024] [Indexed: 06/14/2024]
Abstract
The function of TERRA in the regulation of telomerase in human cells is still debated. While TERRA interacts with telomerase, how it regulates telomerase function remains unknown. Here, we show that TERRA colocalizes with the telomerase RNA subunit hTR in the nucleoplasm and at telomeres during different phases of the cell cycle. We report that TERRA transcripts relocate away from chromosome ends during telomere lengthening, leading to a reduced number of telomeric TERRA-hTR molecules and consequent increase in "TERRA-free" telomerase molecules at telomeres. Using live-cell imaging and super-resolution microscopy, we show that upon transcription, TERRA relocates from its telomere of origin to long chromosome ends. Furthermore, TERRA depletion by antisense oligonucleotides promoted hTR localization to telomeres, leading to increased residence time and extended half-life of hTR molecules at telomeres. Overall, our findings indicate that telomeric TERRA transcripts inhibit telomere elongation by telomerase acting in trans, impairing telomerase access to telomeres that are different from their chromosome end of origin.
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Affiliation(s)
- Nicole Bettin
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Emmanuelle Querido
- Department of Biochemistry and Molecular Medicine, University of Montreal, 2900 boul. Edouard Montpetit, H3T1J4 Montreal, Canada
| | - Irene Gialdini
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Glenda Paola Grupelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Elena Goretti
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Marta Cantarelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Marta Andolfato
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Eslam Soror
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Alessandra Sontacchi
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Katarina Jurikova
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina, 84215 Bratislava, Slovakia
| | - Pascal Chartrand
- Department of Biochemistry and Molecular Medicine, University of Montreal, 2900 boul. Edouard Montpetit, H3T1J4 Montreal, Canada
| | - Emilio Cusanelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, via Sommarive 9, 38123 Trento, Italy
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2
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Hinchie AM, Sanford SL, Loughridge KE, Sutton RM, Parikh AH, Gil Silva AA, Sullivan DI, Chun-On P, Morrell MR, McDyer JF, Opresko PL, Alder JK. A persistent variant telomere sequence in a human pedigree. Nat Commun 2024; 15:4681. [PMID: 38824190 PMCID: PMC11144197 DOI: 10.1038/s41467-024-49072-9] [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: 01/20/2024] [Accepted: 05/22/2024] [Indexed: 06/03/2024] Open
Abstract
The telomere sequence, TTAGGG, is conserved across all vertebrates and plays an essential role in suppressing the DNA damage response by binding a set of proteins termed shelterin. Changes in the telomere sequence impair shelterin binding, initiate a DNA damage response, and are toxic to cells. Here we identify a family with a variant in the telomere template sequence of telomerase, the enzyme responsible for telomere elongation, that led to a non-canonical telomere sequence. The variant is inherited across at least one generation and one family member reports no significant medical concerns despite ~9% of their telomeres converting to the novel sequence. The variant template disrupts telomerase repeat addition processivity and decreased the binding of the telomere-binding protein POT1. Despite these disruptions, the sequence is readily incorporated into cellular chromosomes. Incorporation of a variant sequence prevents POT1-mediated inhibition of telomerase suggesting that incorporation of a variant sequence may influence telomere addition. These findings demonstrate that telomeres can tolerate substantial degeneracy while remaining functional and provide insights as to how incorporation of a non-canonical telomere sequence might alter telomere length dynamics.
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Affiliation(s)
- Angela M Hinchie
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Samantha L Sanford
- Environmental and Occupational Health Department, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center, Hillman Cancer Center, Pittsburgh, PA, USA
| | - Kelly E Loughridge
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rachel M Sutton
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Anishka H Parikh
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Agustin A Gil Silva
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel I Sullivan
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Pattra Chun-On
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew R Morrell
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - John F McDyer
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Patricia L Opresko
- Environmental and Occupational Health Department, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center, Hillman Cancer Center, Pittsburgh, PA, USA
- Pharmacology and Chemical Biology Department, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan K Alder
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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3
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Wang QL, Gong C, Meng XY, Fu M, Yang H, Zhou F, Wu Q, Zhou Y. TPP1 is associated with risk of advanced precursors and cervical cancer survival. PLoS One 2024; 19:e0298118. [PMID: 38722833 PMCID: PMC11081309 DOI: 10.1371/journal.pone.0298118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/16/2024] [Indexed: 05/13/2024] Open
Abstract
It is unclear how telomere-binding protein TPP1 interacts with human telomerase reverse transcriptase (hTERT) and influences cervical cancer development and progression. This study included all eligible 156 cervical cancers diagnosed during 2003-2008 and followed up through 2014, 102 cervical intraepithelial neoplasia (CIN) patients, and 16 participants with normal cervix identified at the same period. Correlation of expression of TPP1 and hTERT in these lesions was assessed using Kappa statistics. TPP1 was knocked down by siRNA in three cervical cancer cell lines. We assessed mRNA expression using quantitative real-time polymerase chain reaction and protein expression using tissue microarray-based immunohistochemical staining. We further analyzed the impact of TPP1 expression on the overall survival of cervical cancer patients by calculating the hazard ratio (HR) with 95% confidence intervals (CIs) using the multivariable-adjusted Cox regression model. Compared to the normal cervix, high TPP1expression was significantly associated with CIN 3 and cervical cancers (P<0.001 for both). Expressions of TPP1 and hTERT were highly correlated in CIN 3 (Kappa statistics = 0.50, P = 0.005), squamous cell carcinoma (Kappa statistics = 0.22, P = 0.011), and adenocarcinoma/adenosquamous carcinoma (Kappa statistics = 0.77, P = 0.001). Mechanistically, knockdown of TPP1 inhibited the expression of hTERT in both mRNA and protein levels. High expression of TPP1 (HR = 2.61, 95% CI 1.23-5.51) and co-high expression of TPP1 and hTERT (HR = 2.38, 95% CI 1.28-4.43) were independently associated with worse survival in cervical cancer patients. TPP1 and hTERT expression was correlated and high expression of TPP1 was associated with high risk of CIN 3 and cervical cancer and could predict a worse survival in cervical cancer.
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Affiliation(s)
- Qiao-Li Wang
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, United States of America
| | - Caifeng Gong
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiang-Yu Meng
- Health Science Center, Hubei Minzu University, Enshi, China
| | - Min Fu
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Yang
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Fuxiang Zhou
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Qiuji Wu
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Yunfeng Zhou
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
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4
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Tao HY, Zhao CY, Wang Y, Sheng WJ, Zhen YS. Targeting Telomere Dynamics as an Effective Approach for the Development of Cancer Therapeutics. Int J Nanomedicine 2024; 19:3805-3825. [PMID: 38708177 PMCID: PMC11069074 DOI: 10.2147/ijn.s448556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/14/2024] [Indexed: 05/07/2024] Open
Abstract
Telomere is a protective structure located at the end of chromosomes of eukaryotes, involved in maintaining the integrity and stability of the genome. Telomeres play an essential role in cancer progression; accordingly, targeting telomere dynamics emerges as an effective approach for the development of cancer therapeutics. Targeting telomere dynamics may work through multifaceted molecular mechanisms; those include the activation of anti-telomerase immune responses, shortening of telomere lengths, induction of telomere dysfunction and constitution of telomerase-responsive drug release systems. In this review, we summarize a wide variety of telomere dynamics-targeted agents in preclinical studies and clinical trials, and reveal their promising therapeutic potential in cancer therapy. As shown, telomere dynamics-active agents are effective as anti-cancer chemotherapeutics and immunotherapeutics. Notably, these agents may display efficacy against cancer stem cells, reducing cancer stem levels. Furthermore, these agents can be integrated with the capability of tumor-specific drug delivery by the constitution of related nanoparticles, antibody drug conjugates and HSA-based drugs.
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Affiliation(s)
- Hong-yu Tao
- Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
| | - Chun-yan Zhao
- Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
| | - Ying Wang
- Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
| | - Wei-jin Sheng
- Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
| | - Yong-su Zhen
- Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China
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5
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Fernández-Varas B, Manguan-García C, Rodriguez-Centeno J, Mendoza-Lupiáñez L, Calatayud J, Perona R, Martín-Martínez M, Gutierrez-Rodriguez M, Benítez-Buelga C, Sastre L. Clinical mutations in the TERT and TERC genes coding for telomerase components induced oxidative stress, DNA damage at telomeres and cell apoptosis besides decreased telomerase activity. Hum Mol Genet 2024; 33:818-834. [PMID: 38641551 PMCID: PMC11031360 DOI: 10.1093/hmg/ddae015] [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: 10/02/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 04/21/2024] Open
Abstract
Telomeres are nucleoprotein structures at the end of chromosomes that maintain their integrity. Mutations in genes coding for proteins involved in telomere protection and elongation produce diseases such as dyskeratosis congenita or idiopathic pulmonary fibrosis known as telomeropathies. These diseases are characterized by premature telomere shortening, increased DNA damage and oxidative stress. Genetic diagnosis of telomeropathy patients has identified mutations in the genes TERT and TERC coding for telomerase components but the functional consequences of many of these mutations still have to be experimentally demonstrated. The activity of twelve TERT and five TERC mutants, five of them identified in Spanish patients, has been analyzed. TERT and TERC mutants were expressed in VA-13 human cells that express low telomerase levels and the activity induced was analyzed. The production of reactive oxygen species, DNA oxidation and TRF2 association at telomeres, DNA damage response and cell apoptosis were determined. Most mutations presented decreased telomerase activity, as compared to wild-type TERT and TERC. In addition, the expression of several TERT and TERC mutants induced oxidative stress, DNA oxidation, DNA damage, decreased recruitment of the shelterin component TRF2 to telomeres and increased apoptosis. These observations might indicate that the increase in DNA damage and oxidative stress observed in cells from telomeropathy patients is dependent on their TERT or TERC mutations. Therefore, analysis of the effect of TERT and TERC mutations of unknown function on DNA damage and oxidative stress could be of great utility to determine the possible pathogenicity of these variants.
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Affiliation(s)
- Beatriz Fernández-Varas
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
| | - Cristina Manguan-García
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
- Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III. C. Melchor Fernandez de Almagro, 3, 28029 Madrid, Spain
| | - Javier Rodriguez-Centeno
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
| | - Lucía Mendoza-Lupiáñez
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
| | - Joaquin Calatayud
- Departamento de Biología y Geología, Física y Química inorgánica. ESCET, Universidad Rey Juan Carlos, C/Tulipán s/n, Móstoles, C.P. 28933 Madrid, Spain
| | - Rosario Perona
- Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III. C. Melchor Fernandez de Almagro, 3, 28029 Madrid, Spain
- Instituto de Salud Carlos III. Calle Monforte de Lemos 5, 28029 Madrid, Spain
| | | | | | - Carlos Benítez-Buelga
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomedicas Sols/Morreale CSIC/UAM, Arturo Duperier 4, 28029 Madrid, Spain
- Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III. C. Melchor Fernandez de Almagro, 3, 28029 Madrid, Spain
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6
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Bertrand A, Ba I, Kermasson L, Pirabakaran V, Chable N, Lainey E, Ménard C, Kallel F, Picard C, Hadiji S, Coolen-Allou N, Blanchard E, de Villartay JP, Moshous D, Roelens M, Callebaut I, Kannengiesser C, Revy P. Characterization of novel mutations in the TEL-patch domain of the telomeric factor TPP1 associated with telomere biology disorders. Hum Mol Genet 2024; 33:612-623. [PMID: 38176734 DOI: 10.1093/hmg/ddad210] [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: 07/11/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
Telomeres are nucleoprotein structures that protect the chromosome ends from degradation and fusion. Telomerase is a ribonucleoprotein complex essential to maintain the length of telomeres. Germline defects that lead to short and/or dysfunctional telomeres cause telomere biology disorders (TBDs), a group of rare and heterogeneous Mendelian diseases including pulmonary fibrosis, dyskeratosis congenita, and Høyeraal-Hreidarsson syndrome. TPP1, a telomeric factor encoded by the gene ACD, recruits telomerase at telomere and stimulates its activity via its TEL-patch domain that directly interacts with TERT, the catalytic subunit of telomerase. TBDs due to TPP1 deficiency have been reported only in 11 individuals. We here report four unrelated individuals with a wide spectrum of TBD manifestations carrying either heterozygous or homozygous ACD variants consisting in the recurrent and previously described in-frame deletion of K170 (K170∆) and three novel missense mutations G179D, L184R, and E215V. Structural and functional analyses demonstrated that the four variants affect the TEL-patch domain of TPP1 and impair telomerase activity. In addition, we identified in the ACD gene several motifs associated with small deletion hotspots that could explain the recurrence of the K170∆ mutation. Finally, we detected in a subset of blood cells from one patient, a somatic TERT promoter-activating mutation that likely provides a selective advantage over non-modified cells, a phenomenon known as indirect somatic genetic rescue. Together, our results broaden the genetic and clinical spectrum of TPP1 deficiency and specify new residues in the TEL-patch domain that are crucial for length maintenance and stability of human telomeres in vivo.
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Affiliation(s)
- Alexis Bertrand
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Ibrahima Ba
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Laëtitia Kermasson
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Vithura Pirabakaran
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Noémie Chable
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Elodie Lainey
- Hematology Laboratory, Robert Debré Hospital-AssistancePublique-Hôpitaux de Paris (APHP), INSERM UMR 1131-Hematology University Institute-Denis Diderot School of Medicine, Paris 75019, France
| | - Christelle Ménard
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Faten Kallel
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Capucine Picard
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Institut Imagine, Paris 75015, France
| | - Sondes Hadiji
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Nathalie Coolen-Allou
- Service de Pneumologie, Hôpital Félix Guyon, CHU Réunion, Saint-Denis de la Réunion 97400, France
| | - Elodie Blanchard
- Service de Pneumologie, Hôpital Haut-Lévêque, CHU Bordeaux, Bordeaux 33604, France
| | - Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Despina Moshous
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
| | - Marie Roelens
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris 75005, France
| | - Caroline Kannengiesser
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
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7
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Olson CL, Wuttke DS. Guardians of the Genome: How the Single-Stranded DNA-Binding Proteins RPA and CST Facilitate Telomere Replication. Biomolecules 2024; 14:263. [PMID: 38540683 PMCID: PMC10968030 DOI: 10.3390/biom14030263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/02/2024] [Accepted: 02/20/2024] [Indexed: 04/26/2024] Open
Abstract
Telomeres act as the protective caps of eukaryotic linear chromosomes; thus, proper telomere maintenance is crucial for genome stability. Successful telomere replication is a cornerstone of telomere length regulation, but this process can be fraught due to the many intrinsic challenges telomeres pose to the replication machinery. In addition to the famous "end replication" problem due to the discontinuous nature of lagging strand synthesis, telomeres require various telomere-specific steps for maintaining the proper 3' overhang length. Bulk telomere replication also encounters its own difficulties as telomeres are prone to various forms of replication roadblocks. These roadblocks can result in an increase in replication stress that can cause replication forks to slow, stall, or become reversed. Ultimately, this leads to excess single-stranded DNA (ssDNA) that needs to be managed and protected for replication to continue and to prevent DNA damage and genome instability. RPA and CST are single-stranded DNA-binding protein complexes that play key roles in performing this task and help stabilize stalled forks for continued replication. The interplay between RPA and CST, their functions at telomeres during replication, and their specialized features for helping overcome replication stress at telomeres are the focus of this review.
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Affiliation(s)
- Conner L. Olson
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Deborah S. Wuttke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
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8
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Arnoult N, Cech TR. Telomerase misbehaves after a breakup. Science 2024; 383:702-703. [PMID: 38359118 DOI: 10.1126/science.adn7791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Suppressing telomerase action at broken DNA preserves genome integrity.
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Affiliation(s)
- Nausica Arnoult
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Thomas R Cech
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
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9
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Ertunc O, Smearman E, Zheng Q, Hicks JL, Brosnan-Cashman JA, Jones T, Gomes-Alexandre C, Trabzonlu L, Meeker AK, De Marzo AM, Heaphy CM. Chromogenic detection of telomere lengths in situ aids the identification of precancerous lesions in the prostate. Prostate 2024; 84:148-157. [PMID: 37849074 PMCID: PMC10843147 DOI: 10.1002/pros.24633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/05/2023] [Accepted: 09/19/2023] [Indexed: 10/19/2023]
Abstract
BACKGROUND Telomeres are terminal chromosomal elements that are essential for the maintenance of genomic integrity. The measurement of telomere content provides useful diagnostic and prognostic information, and fluorescent methods have been developed for this purpose. However, fluorescent-based tissue assays are cumbersome for investigators to undertake, both in research and clinical settings. METHODS A robust chromogenic in situ hybridization (CISH) approach was developed to visualize and quantify telomere content at single cell resolution in human prostate tissues, both frozen and formalin-fixed, paraffin-embedded (FFPE). RESULTS This new assay (telomere chromogenic in situ hybridization ["Telo-CISH"]) produces permanently stained slides that are viewable with a standard light microscope, thus avoiding the need for specialized equipment and storage. The assay is compatible with standard immunohistochemistry, thereby allowing simultaneous assessment of histomorphology, identification of specific cell types, and assessment of telomere status. In addition, Telo-CISH eliminates the problem of autofluorescent interference that frequently occurs with fluorescent-based methods. Using this new assay, we demonstrate successful application of Telo-CISH to help identify precancerous lesions in the prostate by the presence of markedly short telomeres specifically in the luminal epithelial cells. CONCLUSIONS In summary, with fewer restrictions on the types of tissues that can be tested, and increased histologic information provided, the advantages presented by this novel chromogenic assay should extend the applicability of tissue-based telomere length assessment in research and clinical settings.
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Affiliation(s)
- Onur Ertunc
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Erica Smearman
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Qizhi Zheng
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jessica L. Hicks
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Tracy Jones
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Levent Trabzonlu
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alan K. Meeker
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Sidney Kimmel Comprehensive Cancer Institute at Johns Hopkins, Baltimore, Maryland
| | - Angelo M. De Marzo
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Sidney Kimmel Comprehensive Cancer Institute at Johns Hopkins, Baltimore, Maryland
| | - Christopher M. Heaphy
- Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
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10
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Lim CJ. Telomere C-Strand Fill-In Machinery: New Insights into the Human CST-DNA Polymerase Alpha-Primase Structures and Functions. Subcell Biochem 2024; 104:73-100. [PMID: 38963484 DOI: 10.1007/978-3-031-58843-3_5] [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] [Indexed: 07/05/2024]
Abstract
Telomeres at the end of eukaryotic chromosomes are extended by a specialized set of enzymes and telomere-associated proteins, collectively termed here the telomere "replisome." The telomere replisome acts on a unique replicon at each chromosomal end of the telomeres, the 3' DNA overhang. This telomere replication process is distinct from the replisome mechanism deployed to duplicate the human genome. The G-rich overhang is first extended before the complementary C-strand is filled in. This overhang is extended by telomerase, a specialized ribonucleoprotein and reverse transcriptase. The overhang extension process is terminated when telomerase is displaced by CTC1-STN1-TEN1 (CST), a single-stranded DNA-binding protein complex. CST then recruits DNA polymerase α-primase to complete the telomere replication process by filling in the complementary C-strand. In this chapter, the recent structure-function insights into the human telomere C-strand fill-in machinery (DNA polymerase α-primase and CST) will be discussed.
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Affiliation(s)
- Ci Ji Lim
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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11
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Li B. Telomere maintenance in African trypanosomes. Front Mol Biosci 2023; 10:1302557. [PMID: 38074093 PMCID: PMC10704157 DOI: 10.3389/fmolb.2023.1302557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/15/2023] [Indexed: 02/12/2024] Open
Abstract
Telomere maintenance is essential for genome integrity and chromosome stability in eukaryotic cells harboring linear chromosomes, as telomere forms a specialized structure to mask the natural chromosome ends from DNA damage repair machineries and to prevent nucleolytic degradation of the telomeric DNA. In Trypanosoma brucei and several other microbial pathogens, virulence genes involved in antigenic variation, a key pathogenesis mechanism essential for host immune evasion and long-term infections, are located at subtelomeres, and expression and switching of these major surface antigens are regulated by telomere proteins and the telomere structure. Therefore, understanding telomere maintenance mechanisms and how these pathogens achieve a balance between stability and plasticity at telomere/subtelomere will help develop better means to eradicate human diseases caused by these pathogens. Telomere replication faces several challenges, and the "end replication problem" is a key obstacle that can cause progressive telomere shortening in proliferating cells. To overcome this challenge, most eukaryotes use telomerase to extend the G-rich telomere strand. In addition, a number of telomere proteins use sophisticated mechanisms to coordinate the telomerase-mediated de novo telomere G-strand synthesis and the telomere C-strand fill-in, which has been extensively studied in mammalian cells. However, we recently discovered that trypanosomes lack many telomere proteins identified in its mammalian host that are critical for telomere end processing. Rather, T. brucei uses a unique DNA polymerase, PolIE that belongs to the DNA polymerase A family (E. coli DNA PolI family), to coordinate the telomere G- and C-strand syntheses. In this review, I will first briefly summarize current understanding of telomere end processing in mammals. Subsequently, I will describe PolIE-mediated coordination of telomere G- and C-strand synthesis in T. brucei and implication of this recent discovery.
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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 Arts and Sciences, 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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12
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Aureli S, Cardenas VB, Raniolo S, Limongelli V. Conformational plasticity and allosteric communication networks explain Shelterin protein TPP1 binding to human telomerase. Commun Chem 2023; 6:242. [PMID: 37935941 PMCID: PMC10630336 DOI: 10.1038/s42004-023-01040-y] [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: 02/27/2023] [Accepted: 10/24/2023] [Indexed: 11/09/2023] Open
Abstract
The Shelterin complex protein TPP1 interacts with human telomerase (TERT) by means of the TEL-patch region, controlling telomere homeostasis. Aberrations in the TPP1-TERT heterodimer formation might lead to short telomeres and severe diseases like dyskeratosis congenita and Hoyeraal-Hreidarsson syndrome. In the present study, we provide a thorough characterization of the structural properties of the TPP1's OB-domain by combining data coming from microsecond-long molecular dynamics calculations, time-series analyses, and graph-based networks. Our results show that the TEL-patch conformational freedom is influenced by a network of long-range amino acid communications that together determine the proper TPP1-TERT binding. Furthermore, we reveal that in TPP1 pathological variants Glu169Δ, Lys170Δ and Leu95Gln, the TEL-patch plasticity is reduced, affecting the correct binding to TERT and, in turn, telomere processivity, which eventually leads to accelerated aging of affected cells. Our study provides a structural basis for the design of TPP1-targeting ligands with therapeutic potential against cancer and telomeropathies.
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Affiliation(s)
- Simone Aureli
- Faculty of Biomedical Sciences, Euler Institute, Università della Svizzera italiana (USI), via G. Buffi 13, Lugano, CH-6900, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneve, Rue Michel-Servet 1, Geneva, CH-1211, Switzerland
- Swiss Institute of Bioinformatics, University of Geneve, Geneva, CH-1206, Switzerland
| | - Vince Bart Cardenas
- Faculty of Biomedical Sciences, Euler Institute, Università della Svizzera italiana (USI), via G. Buffi 13, Lugano, CH-6900, Switzerland
| | - Stefano Raniolo
- Faculty of Biomedical Sciences, Euler Institute, Università della Svizzera italiana (USI), via G. Buffi 13, Lugano, CH-6900, Switzerland
| | - Vittorio Limongelli
- Faculty of Biomedical Sciences, Euler Institute, Università della Svizzera italiana (USI), via G. Buffi 13, Lugano, CH-6900, Switzerland.
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13
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Gold NM, Okeke MN, He Y. Involvement of Inheritance in Determining Telomere Length beyond Environmental and Lifestyle Factors. Aging Dis 2023:AD.2023.1023. [PMID: 37962459 DOI: 10.14336/ad.2023.1023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
All linear chromosomal ends have specific DNA-protein complexes called telomeres. Telomeres serve as a "molecular clock" to estimate the potential length of cell replication. Shortening of telomere length (TL) is associated with cellular senescence, aging, and various age-related diseases in humans. Here we reviewed the structure, function, and regulation of telomeres and the age-related diseases associated with telomere attrition. Among the various determinants of TL, we highlight the connection between TL and heredity to provide a new overview of genetic determinants for TL. Studies across multiple species have shown that maternal and paternal TL influence the TL of their offspring, and this may affect life span and their susceptibility to age-related diseases. Hence, we reviewed the linkage between TL and parental influences and the proposed mechanisms involved. More in-depth studies on the genetic mechanism for TL attrition are needed due to the potential application of this knowledge in human medicine to prevent premature frailty at its earliest stage, as well as promote health and longevity.
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Affiliation(s)
- Naheemat Modupeola Gold
- Key Laboratory of Healthy Aging Research of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- State Key Laboratory of Genetic, Evolution and Animal Models, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Michael Ngozi Okeke
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Nanomedical Technology Research, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yonghan He
- Key Laboratory of Healthy Aging Research of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- State Key Laboratory of Genetic, Evolution and Animal Models, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Sienkiewicz M, Sroka K, Binienda A, Jurk D, Fichna J. A new face of old cells: An overview about the role of senescence and telomeres in inflammatory bowel diseases. Ageing Res Rev 2023; 91:102083. [PMID: 37802318 DOI: 10.1016/j.arr.2023.102083] [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: 08/21/2023] [Revised: 10/01/2023] [Accepted: 10/02/2023] [Indexed: 10/08/2023]
Abstract
Cellular senescence is a pivotal factor contributing to aging and the pathophysiology of age-related diseases. Despite the presence of inflammation and abnormal immune system function in both inflammatory bowel diseases (IBD) and senescence, the relationship between the two remains largely unexplored. Therefore, our study aimed to investigate the intricate connection between cellular senescence, telomeres, and IBD. The review highlights the presence of senescence markers, particularly p16 and p21, in IBD patients, suggesting their potential association with disease progression and mucosal inflammation. We emphasize the critical role of macrophages in eliminating senescent cells and how disturbance in effective clearance may contribute to persistent senescence and inflammation in IBD. Additionally, we shed light on the involvement of telomeres in IBD, as their dysfunction impairs enterocyte function and disrupts colonic barrier integrity, potentially exacerbating the pathogenesis of the disease. Targeting senescence and telomere dysfunctions holds promise for the development of innovative therapeutic approaches to mitigate intestinal inflammation and alleviate symptoms in IBD patients. By unraveling the precise role of senescence in IBD, we can pave the way for the discovery of novel therapeutic interventions that effectively address the underlying mechanisms of intestinal inflammation, offering hope for improved management and treatment of IBD patients.
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Affiliation(s)
- Michał Sienkiewicz
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Kamila Sroka
- Department of Family Medicine and Public Health, University of Opole, Opole, Poland
| | - Agata Binienda
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Diana Jurk
- Robert and Arlene Kogod Center On Aging, Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Jakub Fichna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
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15
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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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16
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He Q, Lim CJ. Models for human telomere C-strand fill-in by CST-Polα-primase. Trends Biochem Sci 2023; 48:860-872. [PMID: 37586999 PMCID: PMC10528720 DOI: 10.1016/j.tibs.2023.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023]
Abstract
Telomere maintenance is essential for the genome integrity of eukaryotes, and this function is underpinned by the two-step telomeric DNA synthesis process: telomere G-overhang extension by telomerase and complementary strand fill-in by DNA polymerase alpha-primase (polα-primase). Compared to the telomerase step, the telomere C-strand fill-in mechanism is less understood. Recent studies have provided new insights into how telomeric single-stranded DNA-binding protein CTC1-STN1-TEN1 (CST) and polα-primase coordinate to synthesize the telomeric C-strand for telomere overhang fill-in. Cryogenic electron microscopy (cryo-EM) structures of CST-polα-primase complexes have provided additional insights into how they assemble at telomeric templates and de novo synthesize the telomere C-strand. In this review, we discuss how these latest findings coalesce with existing understanding to develop a human telomere C-strand fill-in mechanism model.
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Affiliation(s)
- Qixiang He
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
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17
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Li Q, Wang X, Liu J, Wu L, Xu S. POT1 involved in telomeric DNA damage repair and genomic stability of cervical cancer cells in response to radiation. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 891:503670. [PMID: 37770150 DOI: 10.1016/j.mrgentox.2023.503670] [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: 04/30/2023] [Revised: 07/25/2023] [Accepted: 08/05/2023] [Indexed: 10/03/2023]
Abstract
Though telomeres play a crucial role in maintaining genomic stability in cancer cells and have emerged as attractive therapeutic targets in anticancer therapy, the relationship between telomere dysfunction and genomic instability induced by irradiation is still unclear. In this study, we identified that protection of telomeres 1 (POT1), a single-stranded DNA (ssDNA)-binding protein, was upregulated in γ-irradiated HeLa cells and in cancer patients who exhibit radiation tolerance. Knockdown of POT1 delayed the repair of radiation-induced telomeric DNA damage which was associated with enhanced H3K9 trimethylation and enhanced the radiosensitivity of HeLa cells. The depletion of POT1 also resulted in significant genomic instability, by showing a significant increase in end-to-end chromosomal fusions, and the formation of anaphase bridges and micronuclei. Furthermore, knockdown of POT1 disturbed telomerase recruitment to telomere, and POT1 could interact with phosphorylated ATM (p-ATM) and POT1 depletion decreased the levels of p-ATM induced by irradiation, suggesting that POT1 could regulate the telomerase recruitment to telomeres to repair irradiation-induced telomeric DNA damage of HeLa cells through interactions with p-ATM. The enhancement of radiosensitivity in cancer cells can be achieved through the combination of POT1 and telomerase inhibitors, presenting a potential approach for radiotherapy in cancer treatment.
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Affiliation(s)
- Qian Li
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Xiaofei Wang
- School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Jie Liu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China
| | - Lijun Wu
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
| | - Shengmin Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
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18
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Takasugi T, Gu P, Liang F, Staco I, Chang S. Pot1b -/- tumors activate G-quadruplex-induced DNA damage to promote telomere hyper-elongation. Nucleic Acids Res 2023; 51:9227-9247. [PMID: 37560909 PMCID: PMC10516629 DOI: 10.1093/nar/gkad648] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/14/2023] [Accepted: 07/22/2023] [Indexed: 08/11/2023] Open
Abstract
Malignant cancers must activate telomere maintenance mechanisms to achieve replicative immortality. Mutations in the human Protection of Telomeres 1 (POT1) gene are frequently detected in cancers with abnormally long telomeres, suggesting that the loss of POT1 function disrupts the regulation of telomere length homeostasis to promote telomere elongation. However, our understanding of the mechanisms leading to elongated telomeres remains incomplete. The mouse genome encodes two POT1 proteins, POT1a and POT1b possessing separation of hPOT1 functions. We performed serial transplantation of Pot1b-/- sarcomas to better understand the role of POT1b in regulating telomere length maintenance. While early-generation Pot1b-/- sarcomas initially possessed shortened telomeres, late-generation Pot1b-/- cells display markedly hyper-elongated telomeres that were recognized as damaged DNA by the Replication Protein A (RPA) complex. The RPA-ATR-dependent DNA damage response at telomeres promotes telomerase recruitment to facilitate telomere hyper-elongation. POT1b, but not POT1a, was able to unfold G-quadruplex present in hyper-elongated telomeres to repress the DNA damage response. Our findings demonstrate that the repression of the RPA-ATR DDR is conserved between POT1b and human POT1, suggesting that similar mechanisms may underly the phenotypes observed in human cancers harboring human POT1 mutations.
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Affiliation(s)
- Taylor Takasugi
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Peili Gu
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Fengshan Liang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Isabelle Staco
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sandy Chang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
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19
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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: 1] [Impact Index Per Article: 1.0] [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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20
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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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21
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Lue NF, Autexier C. Orchestrating nucleic acid-protein interactions at chromosome ends: telomerase mechanisms come into focus. Nat Struct Mol Biol 2023; 30:878-890. [PMID: 37400652 PMCID: PMC10539978 DOI: 10.1038/s41594-023-01022-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/16/2023] [Indexed: 07/05/2023]
Abstract
Telomerase is a special reverse transcriptase ribonucleoprotein dedicated to the synthesis of telomere repeats that protect chromosome ends. Among reverse transcriptases, telomerase is unique in using a stably associated RNA with an embedded template to synthesize a specified sequence. Moreover, it is capable of iteratively copying the same template region (repeat addition processivity) through multiple rounds of RNA-DNA unpairing and reannealing, that is, the translocation reaction. Biochemical analyses of telomerase over the past 3 decades in protozoa, fungi and mammals have identified structural elements that underpin telomerase mechanisms and have led to models that account for the special attributes of telomerase. Notably, these findings and models can now be interpreted and adjudicated through recent cryo-EM structures of Tetrahymena and human telomerase holoenzyme complexes in association with substrates and regulatory proteins. Collectively, these structures reveal the intricate protein-nucleic acid interactions that potentiate telomerase's unique translocation reaction and clarify how this enzyme reconfigures the basic reverse transcriptase scaffold to craft a polymerase dedicated to the synthesis of telomere DNA. Among the many new insights is the resolution of the telomerase 'anchor site' proposed more than 3 decades ago. The structures also highlight the nearly universal conservation of a protein-protein interface between an oligonucleotide/oligosaccharide-binding (OB)-fold regulatory protein and the telomerase catalytic subunit, which enables spatial and temporal regulation of telomerase function in vivo. In this Review, we discuss key features of the structures in combination with relevant functional analyses. We also examine conserved and divergent aspects of telomerase mechanisms as gleaned from studies in different model organisms.
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Affiliation(s)
- Neal F Lue
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA.
| | - Chantal Autexier
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Anatomy and Cell Biology and Department of Medicine, McGill University, Montreal, Quebec, Canada.
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22
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Klump BM, Perez GI, Patrick EM, Adams-Boone K, Cohen SB, Han L, Yu K, Schmidt JC. TCAB1 prevents nucleolar accumulation of the telomerase RNA to facilitate telomerase assembly. Cell Rep 2023; 42:112577. [PMID: 37267110 PMCID: PMC10569210 DOI: 10.1016/j.celrep.2023.112577] [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: 01/07/2023] [Revised: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 06/04/2023] Open
Abstract
Localization of a variety of RNAs to non-membrane-bound cellular compartments such as nucleoli and Cajal bodies is critical for their stability and function. The molecular mechanisms that underly the recruitment and exclusion of RNAs from these phase-separated organelles is incompletely understood. Telomerase is a ribonucleoprotein composed of the reverse transcriptase protein telomerase reverse transcriptase (TERT), the telomerase RNA (TR), and several auxiliary proteins, including TCAB1. Here we show that in the absence of TCAB1, a large fraction of TR is tightly bound to the nucleolus, while TERT is largely excluded from the nucleolus, reducing telomerase assembly. This suggests that nuclear compartmentalization by the non-membrane-bound nucleolus counteracts telomerase assembly, and TCAB1 is required to retain TR in the nucleoplasm. Our work provides insight into the mechanism and functional consequences of RNA recruitment to organelles formed by phase separation and demonstrates that TCAB1 plays an important role in telomerase assembly.
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Affiliation(s)
- Basma M Klump
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA; College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA; Cellular and Molecular Biology Graduate Program, College of Natural Sciences, Michigan State University, East Lansing, MI, USA
| | - Gloria I Perez
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Eric M Patrick
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Kate Adams-Boone
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Scott B Cohen
- Children's Medical Research Institute and University of Sydney, Westmead, NSW 2145, Australia
| | - Li Han
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Jens C Schmidt
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA; Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing, MI, USA.
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23
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Wang H, Ma T, Zhang X, Chen W, Lan Y, Kuang G, Hsu SJ, He Z, Chen Y, Stewart J, Bhattacharjee A, Luo Z, Price C, Feng X. CTC1 OB-B interaction with TPP1 terminates telomerase and prevents telomere overextension. Nucleic Acids Res 2023; 51:4914-4928. [PMID: 37021555 PMCID: PMC10250220 DOI: 10.1093/nar/gkad237] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 03/16/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
CST (CTC1-STN1-TEN1) is a telomere associated complex that binds ssDNA and is required for multiple steps in telomere replication, including termination of G-strand extension by telomerase and synthesis of the complementary C-strand. CST contains seven OB-folds which appear to mediate CST function by modulating CST binding to ssDNA and the ability of CST to recruit or engage partner proteins. However, the mechanism whereby CST achieves its various functions remains unclear. To address the mechanism, we generated a series of CTC1 mutants and studied their effect on CST binding to ssDNA and their ability to rescue CST function in CTC1-/- cells. We identified the OB-B domain as a key determinant of telomerase termination but not C-strand synthesis. CTC1-ΔB expression rescued C-strand fill-in, prevented telomeric DNA damage signaling and growth arrest. However, it caused progressive telomere elongation and the accumulation of telomerase at telomeres, indicating an inability to limit telomerase action. The CTC1-ΔB mutation greatly reduced CST-TPP1 interaction but only modestly affected ssDNA binding. OB-B point mutations also weakened TPP1 association, with the deficiency in TPP1 interaction tracking with an inability to limit telomerase action. Overall, our results indicate that CTC1-TPP1 interaction plays a key role in telomerase termination.
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Affiliation(s)
- Huan Wang
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Tengfei Ma
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaotong Zhang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wei Chen
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yina Lan
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guotao Kuang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shih-Jui Hsu
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Zibin He
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yuxi Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jason Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | | | - Zhenhua Luo
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Carolyn Price
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Xuyang Feng
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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24
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Padmanaban S, Tesmer VM, Nandakumar J. Interaction hub critical for telomerase recruitment and primer-template handling for catalysis. Life Sci Alliance 2023; 6:e202201727. [PMID: 36963832 PMCID: PMC10055720 DOI: 10.26508/lsa.202201727] [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: 09/16/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023] Open
Abstract
Telomerase processively adds telomeric DNA repeats to chromosome ends using catalytic protein subunit TERT and a template on its RNA subunit TR. Mammalian telomerase is recruited to telomeres by the TEL patch and NOB regions of shelterin component TPP1. Recent cryo-EM structures of human telomerase reveal that a composite TERT TEN-(IFD-TRAP) domain interacts with TPP1. Here, we generate TERT mutants to demonstrate that a three-way TEN-(IFD-TRAP)-TPP1 interaction is critical for telomerase recruitment to telomeres and processive telomere repeat addition. Single mutations of IFD-TRAP at its interface with TR or the DNA primer impair telomerase catalysis. We further reveal the importance of TERT motif 3N and TEN domain loop 99FGF101 in telomerase action. Finally, we demonstrate that TPP1 TEL patch loop residue F172, which undergoes a structural rearrangement to bind telomerase, contributes to the human-mouse species specificity of the telomerase-TPP1 interaction. Our study provides insights into the multiple functions of TERT IFD-TRAP, reveals novel TERT and TPP1 elements critical for function, and helps explain how TPP1 binding licenses robust telomerase action at natural chromosome ends.
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Affiliation(s)
- Shilpa Padmanaban
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Valerie M Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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25
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Zade NH, Khattar E. POT1 mutations cause differential effects on telomere length leading to opposing disease phenotypes. J Cell Physiol 2023; 238:1237-1255. [PMID: 37183325 DOI: 10.1002/jcp.31034] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/16/2023]
Abstract
The protection of telomere protein (POT1) is a telomere-binding protein and is an essential component of the six-membered shelterin complex, which is associated with the telomeres. POT1 directly binds to the 3' single-stranded telomeric overhang and prevents the activation of DNA damage response at telomeres thus preventing the telomere-telomere fusions and genomic instability. POT1 also plays a pivotal role in maintaining telomere length by regulating telomerase-mediated telomere elongation. Mutations in POT1 proteins result in three different telomere phenotypes, which include long, short, or aberrant telomere length. Long telomeres predispose individuals to cancer, while short or aberrant telomere phenotypes result in pro-aging diseases referred to as telomeropathies. Here, we review the function of POT1 proteins in telomere length hemostasis and how the spectrum of mutations reported in POT1 can be segregated toward developing very distinct disease phenotypes of cancer and telomeropathies.
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Affiliation(s)
- Nikita Harish Zade
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
| | - Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
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26
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Ertunc O, Smearman E, Zheng Q, Hicks JL, Brosnan-Cashman JA, Jones T, Gomes-Alexandre C, Trabzonlu L, Meeker AK, De Marzo AM, Heaphy CM. Chromogenic detection of telomere lengths in situ aids the identification of precancerous lesions in the prostate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.04.535575. [PMID: 37066381 PMCID: PMC10104079 DOI: 10.1101/2023.04.04.535575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Telomeres are terminal chromosomal elements that are essential for the maintenance of genomic integrity. The measurement of telomere content provides useful diagnostic and prognostic information, and fluorescent methods have been developed for this purpose. However, fluorescent-based tissue assays are cumbersome for investigators to undertake, both in research and clinical settings. Here, a robust chromogenic in situ hybridization (CISH) approach was developed to visualize and quantify telomere content at single cell resolution in human prostate tissues, both frozen and formalin-fixed, paraffin-embedded (FFPE). This new assay ("Telo-CISH") produces permanently stained slides that are viewable with a standard light microscope, thus avoiding the need for specialized equipment and storage. The assay is compatible with standard immunohistochemistry, thereby allowing simultaneous assessment of histomorphology, identification of specific cell types, and assessment of telomere status. In addition, Telo-CISH eliminates the problem of autofluorescent interference that frequently occurs with fluorescent-based methods. Using this new assay, we demonstrate successful application of Telo-CISH to help identify precancerous lesions in the prostate by the presence of markedly short telomeres specifically in the luminal epithelial cells. In summary, with fewer restrictions on the types of tissues that can be tested, and increased histologic information provided, the advantages presented by this novel chromogenic assay should extend the applicability of tissue-based telomere length assessment in research and clinical settings.
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Affiliation(s)
- Onur Ertunc
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | - Erica Smearman
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | - Qizhi Zheng
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | - Jessica L. Hicks
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | | | - Tracy Jones
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | | | - Levent Trabzonlu
- The Department of Pathology, The Johns Hopkins University School of Medicine
| | - Alan K. Meeker
- The Department of Pathology, The Johns Hopkins University School of Medicine
- The Department of Urology, The Johns Hopkins University School of Medicine
- The Department of Oncology, The Johns Hopkins University School of Medicine
- The Sidney Kimmel Comprehensive Cancer Institute at Johns Hopkins, Baltimore, Maryland
| | - Angelo M. De Marzo
- The Department of Pathology, The Johns Hopkins University School of Medicine
- The Department of Urology, The Johns Hopkins University School of Medicine
- The Department of Oncology, The Johns Hopkins University School of Medicine
- The Sidney Kimmel Comprehensive Cancer Institute at Johns Hopkins, Baltimore, Maryland
| | - Christopher M. Heaphy
- The Department of Medicine, Boston University, School of Medicine and Boston Medical Center, Boston, Massachusetts
- The Department Pathology and Laboratory Medicine, Boston University, School of Medicine and Boston Medical Center, Boston, Massachusetts
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27
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Sohn EJ, Goralsky JA, Shay JW, Min J. The Molecular Mechanisms and Therapeutic Prospects of Alternative Lengthening of Telomeres (ALT). Cancers (Basel) 2023; 15:cancers15071945. [PMID: 37046606 PMCID: PMC10093677 DOI: 10.3390/cancers15071945] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/14/2023] Open
Abstract
As detailed by the end replication problem, the linear ends of a cell's chromosomes, known as telomeres, shorten with each successive round of replication until a cell enters into a state of growth arrest referred to as senescence. To maintain their immortal proliferation capacity, cancer cells must employ a telomere maintenance mechanism, such as telomerase activation or the Alternative Lengthening of Telomeres pathway (ALT). With only 10-15% of cancers utilizing the ALT mechanism, progress towards understanding its molecular components and associated hallmarks has only recently been made. This review analyzes the advances towards understanding the ALT pathway by: (1) detailing the mechanisms associated with engaging the ALT pathway as well as (2) identifying potential therapeutic targets of ALT that may lead to novel cancer therapeutic treatments. Collectively, these studies indicate that the ALT molecular mechanisms involve at least two distinct pathways induced by replication stress and damage at telomeres. We suggest exploiting tumor dependency on ALT is a promising field of study because it suggests new approaches to ALT-specific therapies for cancers with poorer prognosis. While substantial progress has been made in the ALT research field, additional progress will be required to realize these advances into clinical practices to treat ALT cancers and improve patient prognoses.
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Affiliation(s)
- Eric J Sohn
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Julia A Goralsky
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Jaewon Min
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
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28
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Post-Transcriptional and Post-Translational Modifications in Telomerase Biogenesis and Recruitment to Telomeres. Int J Mol Sci 2023; 24:ijms24055027. [PMID: 36902458 PMCID: PMC10003056 DOI: 10.3390/ijms24055027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Telomere length is associated with the proliferative potential of cells. Telomerase is an enzyme that elongates telomeres throughout the entire lifespan of an organism in stem cells, germ cells, and cells of constantly renewed tissues. It is activated during cellular division, including regeneration and immune responses. The biogenesis of telomerase components and their assembly and functional localization to the telomere is a complex system regulated at multiple levels, where each step must be tuned to the cellular requirements. Any defect in the function or localization of the components of the telomerase biogenesis and functional system will affect the maintenance of telomere length, which is critical to the processes of regeneration, immune response, embryonic development, and cancer progression. An understanding of the regulatory mechanisms of telomerase biogenesis and activity is necessary for the development of approaches toward manipulating telomerase to influence these processes. The present review focuses on the molecular mechanisms involved in the major steps of telomerase regulation and the role of post-transcriptional and post-translational modifications in telomerase biogenesis and function in yeast and vertebrates.
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29
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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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30
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Nelson N, Feurstein S, Niaz A, Truong J, Holien JK, Lucas S, Fairfax K, Dickinson J, Bryan TM. Functional genomics for curation of variants in telomere biology disorder associated genes: A systematic review. Genet Med 2023; 25:100354. [PMID: 36496180 DOI: 10.1016/j.gim.2022.11.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Patients with an underlying telomere biology disorder (TBD) have variable clinical presentations, and they can be challenging to diagnose clinically. A genomic diagnosis for patients presenting with TBD is vital for optimal treatment. Unfortunately, many variants identified during diagnostic testing are variants of uncertain significance. This complicates management decisions, delays treatment, and risks nonuptake of potentially curative therapies. Improved application of functional genomic evidence may reduce variants of uncertain significance classifications. METHODS We systematically searched the literature for published functional assays interrogating TBD gene variants. When possible, established likely benign/benign and likely pathogenic/pathogenic variants were used to estimate the assay sensitivity, specificity, positive predictive value, negative predictive value, and odds of pathogenicity. RESULTS In total, 3131 articles were screened and 151 met inclusion criteria. Sufficient data to enable a PS3/BS3 recommendation were available for TERT variants only. We recommend that PS3 and BS3 can be applied at a moderate and supportive level, respectively. PS3/BS3 application was limited by a lack of assay standardization and limited inclusion of benign variants. CONCLUSION Further assay standardization and assessment of benign variants are required for optimal use of the PS3/BS3 criterion for TBD gene variant classification.
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Affiliation(s)
- Niles Nelson
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia; Department of Molecular Medicine, The Royal Hobart Hospital, Hobart, Tasmania, Australia; Department of Molecular Haematology, The Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
| | - Simone Feurstein
- Section of Hematology, Oncology, and Rheumatology, Department of Internal Medicine, Heidelberg University Hospital, Heidelberg, Germany
| | - Aram Niaz
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, New South Wales, Australia
| | - Jia Truong
- School of Science, STEM College, RMIT University, Bundoora, Victoria, Australia
| | - Jessica K Holien
- School of Science, STEM College, RMIT University, Bundoora, Victoria, Australia
| | - Sionne Lucas
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Kirsten Fairfax
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Joanne Dickinson
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, New South Wales, Australia
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31
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Sanford SL, Opresko PL. UV light-induced dual promoter mutations dismantle the telomeric guardrails in melanoma. DNA Repair (Amst) 2023; 122:103446. [PMID: 36603239 PMCID: PMC9892262 DOI: 10.1016/j.dnarep.2022.103446] [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: 12/09/2022] [Revised: 12/19/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022]
Abstract
Understanding how benign nevi can progress to invasive and metastatic Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USAelanoma is critical for developing interventions and therapeutics for this most deadly form of skin cancer. UV-induced mutations in the telomerase TERT gene promoter occur in the majority of melanomas but fail to prevent telomere shortening despite telomerase upregulation. This suggests additional "hits" are required to enable telomere maintenance. A new study in Science identified somatic variants in the promoter of the gene that encodes telomere shelterin protein TPP1 in human melanomas. These variants show mutational signatures of UV-induced DNA damage and upregulate TPP1 expression, which synergizes with telomerase to lengthen telomeres. This study provides evidence that TPP1 promoter variants are a critical second hit to prevent telomere shortening and promote immortalization of melanoma cells.
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Affiliation(s)
- Samantha L Sanford
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USA; UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USA; UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, USA.
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32
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Revy P, Kannengiesser C, Bertuch AA. Genetics of human telomere biology disorders. Nat Rev Genet 2023; 24:86-108. [PMID: 36151328 DOI: 10.1038/s41576-022-00527-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2022] [Indexed: 01/24/2023]
Abstract
Telomeres are specialized nucleoprotein structures at the ends of linear chromosomes that prevent the activation of DNA damage response and repair pathways. Numerous factors localize at telomeres to regulate their length, structure and function, to avert replicative senescence or genome instability and cell death. In humans, Mendelian defects in several of these factors can result in abnormally short or dysfunctional telomeres, causing a group of rare heterogeneous premature-ageing diseases, termed telomeropathies, short-telomere syndromes or telomere biology disorders (TBDs). Here, we review the TBD-causing genes identified so far and describe their main functions associated with telomere biology. We present molecular aspects of TBDs, including genetic anticipation, phenocopy, incomplete penetrance and somatic genetic rescue, which underlie the complexity of these diseases. We also discuss the implications of phenotypic and genetic features of TBDs on fundamental aspects related to human telomere biology, ageing and cancer, as well as on diagnostic, therapeutic and clinical approaches.
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Affiliation(s)
- Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Nationale contre le Cancer, Paris, France.
- Université Paris Cité, Imagine Institute, Paris, France.
| | - Caroline Kannengiesser
- APHP Service de Génétique, Hôpital Bichat, Paris, France
- Inserm U1152, Université Paris Cité, Paris, France
| | - Alison A Bertuch
- Departments of Paediatrics and Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA
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33
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Lambert-Lanteigne P, Young A, Autexier C. Complex interaction network revealed by mutation of human telomerase 'insertion in fingers' and essential N-terminal domains and the telomere protein TPP1. J Biol Chem 2023; 299:102916. [PMID: 36649908 PMCID: PMC9958494 DOI: 10.1016/j.jbc.2023.102916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/15/2023] Open
Abstract
In the majority of human cancer cells, cellular immortalization depends on the maintenance of telomere length by telomerase. An essential step required for telomerase function is its recruitment to telomeres, which is regulated by the interaction of the telomere protein, TPP1, with the telomerase essential N-terminal (TEN) domain of the human telomerase reverse transcriptase, hTERT. We previously reported that the hTERT 'insertion in fingers domain' (IFD) recruits telomerase to telomeres in a TPP1-dependent manner. Here, we use hTERT truncations and the IFD domain containing mutations in conserved residues or premature aging disease-associated mutations to map the interactions between the IFD and TPP1. We find that the hTERT-IFD domain can interact with TPP1. However, deletion of the IFD motif in hTERT lacking the N-terminus and the C-terminal extension does not abolish interaction with TPP1, suggesting the IFD is not essential for hTERT interaction with TPP1. Several conserved residues in the central IFD-TRAP region that we reported regulate telomerase recruitment to telomeres, and cell immortalization compromise interaction of the hTERT-IFD domain with TPP1 when mutated. Using a similar approach, we find that the IFD domain interacts with the TEN domain but is not essential for intramolecular hTERT interactions with the TEN domain. IFD-TEN interactions are not disrupted by multiple amino acid changes in the IFD or TEN, thus highlighting a complex regulation of IFD-TEN interactions as suggested by recent cryo-EM structures of human telomerase.
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Affiliation(s)
| | - Adrian Young
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Canada; Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
| | - Chantal Autexier
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Canada; Department of Anatomy and Cell Biology, McGill University, Montréal, Canada; Department of Medicine, McGill University, Montréal, Canada.
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34
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Joseph NA, Chen LY. Tethering CST to the telomerase catalytic core—the p50 linchpin. Structure 2022; 30:1563-1564. [DOI: 10.1016/j.str.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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35
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Rouan A, Pousse M, Tambutté E, Djerbi N, Zozaya W, Capasso L, Zoccola D, Tambutté S, Gilson E. Telomere dysfunction is associated with dark-induced bleaching in the reef coral Stylophora pistillata. Mol Ecol 2022; 31:6087-6099. [PMID: 34587336 DOI: 10.1111/mec.16199] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 08/23/2021] [Accepted: 09/15/2021] [Indexed: 01/31/2023]
Abstract
Telomere DNA length is a complex trait controlled by both multiple loci and environmental factors. A growing number of studies are focusing on the impact of stress and stress accumulation on telomere length and the link with survival and fitness in ecological contexts. Here, we investigated the telomere changes occurring in a symbiotic coral, Stylophora pistillata, that has experienced continuous darkness over 6 months. This stress condition led to the loss of its symbionts in a similar manner to that observed during large-scale bleaching events due to climate changes and anthropogenic activities, threatening reef ecosystems worldwide. We found that continuous darkness was associated with telomere length shortening. This result, together with a phylogenetic analysis of the telomere coral proteins and a transcriptome survey of the continuous darkness condition, paves the way for future studies on the role of telomeres in the coral stress response and the importance of environmentally induced telomere shortening in endangered coral species.
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Affiliation(s)
- Alice Rouan
- Université Côte d'Azur-CNRS-Inserm, IRCAN, Nice, France
| | | | - Eric Tambutté
- Department of Marine Biology, Centre Scientifique de Monaco, Monte Carlo, Principality of Monaco
| | - Nadir Djerbi
- Université Côte d'Azur-CNRS-Inserm, IRCAN, Nice, France
| | | | - Laura Capasso
- Department of Marine Biology, Centre Scientifique de Monaco, Monte Carlo, Principality of Monaco.,Collège Doctoral, Sorbonne Université, Paris, France
| | - Didier Zoccola
- Department of Marine Biology, Centre Scientifique de Monaco, Monte Carlo, Principality of Monaco
| | - Sylvie Tambutté
- Department of Marine Biology, Centre Scientifique de Monaco, Monte Carlo, Principality of Monaco
| | - Eric Gilson
- Université Côte d'Azur-CNRS-Inserm, IRCAN, Nice, France.,Department of Medical Genetics, CHU, Nice, France
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36
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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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37
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Chun-on P, Hinchie AM, Beale HC, Gil Silva AA, Rush E, Sander C, Connelly CJ, Seynnaeve BK, Kirkwood JM, Vaske OM, Greider CW, Alder JK. TPP1 promoter mutations cooperate with TERT promoter mutations to lengthen telomeres in melanoma. Science 2022; 378:664-668. [PMID: 36356143 PMCID: PMC10590476 DOI: 10.1126/science.abq0607] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Overcoming replicative senescence is an essential step during oncogenesis, and the reactivation of TERT through promoter mutations is a common mechanism. TERT promoter mutations are acquired in about 75% of melanomas but are not sufficient to maintain telomeres, suggesting that additional mutations are required. We identified a cluster of variants in the promoter of ACD encoding the shelterin component TPP1. ACD promoter variants are present in about 5% of cutaneous melanoma and co-occur with TERT promoter mutations. The two most common somatic variants create or modify binding sites for E-twenty-six (ETS) transcription factors, similar to mutations in the TERT promoter. The variants increase the expression of TPP1 and function together with TERT to synergistically lengthen telomeres. Our findings suggest that TPP1 promoter variants collaborate with TERT activation to enhance telomere maintenance and immortalization in melanoma.
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Affiliation(s)
- Pattra Chun-on
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine; Pittsburgh, PA, USA
- Environmental and Occupational Health Department, School of Public Health, University of Pittsburgh; Pittsburgh, PA, USA
- Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy; Bangkok, Thailand
| | - Angela M. Hinchie
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine; Pittsburgh, PA, USA
| | - Holly C. Beale
- UC Santa Cruz, Genomics Institute, University of California, Santa Cruz; CA, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz; CA, USA
| | - Agustin A. Gil Silva
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine; Pittsburgh, PA, USA
| | - Elizabeth Rush
- University of Pittsburgh Medical Center, Hillman Cancer Institute; Pittsburgh, PA, USA
| | - Cindy Sander
- University of Pittsburgh Medical Center, Hillman Cancer Institute; Pittsburgh, PA, USA
| | - Carla J. Connelly
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine; Baltimore, MD, USA
| | - Brittani K.N. Seynnaeve
- University of Pittsburgh Medical Center, Hillman Cancer Institute; Pittsburgh, PA, USA
- Department of Pediatrics, Division of Pediatric Hematology/Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - John M. Kirkwood
- University of Pittsburgh Medical Center, Hillman Cancer Institute; Pittsburgh, PA, USA
| | - Olena M. Vaske
- UC Santa Cruz, Genomics Institute, University of California, Santa Cruz; CA, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz; CA, USA
| | - Carol W. Greider
- UC Santa Cruz, Genomics Institute, University of California, Santa Cruz; CA, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz; CA, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine; Baltimore, MD, USA
| | - Jonathan K. Alder
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care Medicine; Pittsburgh, PA, USA
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38
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He Y, Feigon J. Telomerase structural biology comes of age. Curr Opin Struct Biol 2022; 76:102446. [PMID: 36081246 PMCID: PMC9884118 DOI: 10.1016/j.sbi.2022.102446] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 01/31/2023]
Abstract
Telomerase is an RNA-protein complex comprising telomerase reverse transcriptase, a non-coding telomerase RNA, and proteins involved in biogenesis, assembly, localization, or recruitment. Telomerase synthesizes the telomeric DNA at the 3'-ends of linear chromosomes. During the past decade, structural studies have defined the architecture of Tetrahymena and human telomerase as well as protein and RNA domain structures, but high-resolution details of interactions remained largely elusive. In the past two years, several sub-4 Å cryo-electron microscopy structures of telomerase were published, including Tetrahymena telomerase at different steps of telomere repeat addition and human telomerase with telomere shelterin proteins that recruit telomerase to telomeres. These and other recent structural studies have expanded our understanding of telomerase assembly, mechanism, recruitment, and mutations leading to disease.
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Affiliation(s)
- Yao He
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA; Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA.
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Exercise regulates shelterin genes and microRNAs implicated in ageing in Thoroughbred horses. Pflugers Arch 2022; 474:1159-1169. [PMID: 36085194 PMCID: PMC9560944 DOI: 10.1007/s00424-022-02745-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/10/2022] [Accepted: 08/29/2022] [Indexed: 11/03/2022]
Abstract
Ageing causes a gradual deterioration of bodily functions and telomere degradation. Excessive telomere shortening leads to cellular senescence and decreases tissue vitality. Six proteins, called shelterin, protect telomere integrity and control telomere length through telomerase-dependent mechanisms. Exercise training appears to maintain telomeres in certain somatic cells, although the underlying molecular mechanisms are incompletely understood. Here, we examined the influence of a single bout of vigorous exercise training on leukocyte telomerase reverse transcriptase (TERT) and shelterin gene expression, and the abundance of three microRNAs (miRNAs) implicated in biological ageing (miRNA-143, -223 and -486-5p) in an elite athlete and large animal model, Thoroughbred horses. Gene and miRNA expression were analysed using primer-based and TaqMan Assay qPCR. Leukocyte TRF1, TRF2 and POT1 expression were all significantly increased whilst miR-223 and miR-486-5p were decreased immediately after vigorous exercise (all p < 0.05), and tended to return to baseline levels 24 h after training. Relative to the young horses (~ 3.9 years old), middle-aged horses (~ 14.8 years old) exhibited reduced leukocyte TERT gene expression, and increased POT1 and miR-223 abundance (all p < 0.05). These data demonstrate that genes transcribing key components of the shelterin-telomere complex are influenced by ageing and dynamically regulated by a single bout of vigorous exercise in a large, athletic mammal - Thoroughbred horses. Our findings also implicate TERT and shelterin gene transcripts as potential targets of miR-223 and miR-486-5p, which are modulated by exercise and may have a role in the telomere maintenance and genomic stability associated with long-term aerobic training.
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40
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The landscape of aging. SCIENCE CHINA LIFE SCIENCES 2022; 65:2354-2454. [PMID: 36066811 PMCID: PMC9446657 DOI: 10.1007/s11427-022-2161-3] [Citation(s) in RCA: 97] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/05/2022] [Indexed: 02/07/2023]
Abstract
Aging is characterized by a progressive deterioration of physiological integrity, leading to impaired functional ability and ultimately increased susceptibility to death. It is a major risk factor for chronic human diseases, including cardiovascular disease, diabetes, neurological degeneration, and cancer. Therefore, the growing emphasis on “healthy aging” raises a series of important questions in life and social sciences. In recent years, there has been unprecedented progress in aging research, particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes. In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases, we review the descriptive, conceptual, and interventive aspects of the landscape of aging composed of a number of layers at the cellular, tissue, organ, organ system, and organismal levels.
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41
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Gao J, Pickett HA. Targeting telomeres: advances in telomere maintenance mechanism-specific cancer therapies. Nat Rev Cancer 2022; 22:515-532. [PMID: 35790854 DOI: 10.1038/s41568-022-00490-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 12/31/2022]
Abstract
Cancer cells establish replicative immortality by activating a telomere-maintenance mechanism (TMM), be it telomerase or the alternative lengthening of telomeres (ALT) pathway. Targeting telomere maintenance represents an intriguing opportunity to treat the vast majority of all cancer types. Whilst telomerase inhibitors have historically been heralded as promising anticancer agents, the reality has been more challenging, and there are currently no therapeutic options for cancer types that use ALT despite their aggressive nature and poor prognosis. In this Review, we discuss the mechanistic differences between telomere maintenance by telomerase and ALT, the current methods used to detect each mechanism, the utility of these tests for clinical diagnosis, and recent developments in the therapeutic strategies being employed to target both telomerase and ALT. We present notable developments in repurposing established therapeutic agents and new avenues that are emerging to target cancer types according to which TMM they employ. These opportunities extend beyond inhibition of telomere maintenance, by finding and exploiting inherent weaknesses in the telomeres themselves to trigger rapid cellular effects that lead to cell death.
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Affiliation(s)
- Jixuan Gao
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia.
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42
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Tummala H, Walne A, Buccafusca R, Alnajar J, Szabo A, Robinson P, McConkie-Rosell A, Wilson M, Crowley S, Kinsler V, Ewins AM, Madapura PM, Patel M, Pontikos N, Codd V, Vulliamy T, Dokal I. Germline thymidylate synthase deficiency impacts nucleotide metabolism and causes dyskeratosis congenita. Am J Hum Genet 2022; 109:1472-1483. [PMID: 35931051 PMCID: PMC9388389 DOI: 10.1016/j.ajhg.2022.06.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/23/2022] [Indexed: 11/19/2022] Open
Abstract
Dyskeratosis congenita (DC) is an inherited bone-marrow-failure disorder characterized by a triad of mucocutaneous features that include abnormal skin pigmentation, nail dystrophy, and oral leucoplakia. Despite the identification of several genetic variants that cause DC, a significant proportion of probands remain without a molecular diagnosis. In a cohort of eight independent DC-affected families, we have identified a remarkable series of heterozygous germline variants in the gene encoding thymidylate synthase (TYMS). Although the inheritance appeared to be autosomal recessive, one parent in each family had a wild-type TYMS coding sequence. Targeted genomic sequencing identified a specific haplotype and rare variants in the naturally occurring TYMS antisense regulator ENOSF1 (enolase super family 1) inherited from the other parent. Lymphoblastoid cells from affected probands have severe TYMS deficiency, altered cellular deoxyribonucleotide triphosphate pools, and hypersensitivity to the TYMS-specific inhibitor 5-fluorouracil. These defects in the nucleotide metabolism pathway resulted in genotoxic stress, defective transcription, and abnormal telomere maintenance. Gene-rescue studies in cells from affected probands revealed that post-transcriptional epistatic silencing of TYMS is occurring via elevated ENOSF1. These cell and molecular abnormalities generated by the combination of germline digenic variants at the TYMS-ENOSF1 locus represent a unique pathogenetic pathway for DC causation in these affected individuals, whereas the parents who are carriers of either of these variants in a singular fashion remain unaffected.
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Affiliation(s)
- Hemanth Tummala
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK.
| | - Amanda Walne
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Roberto Buccafusca
- School of Physical and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - Jenna Alnajar
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Anita Szabo
- Institute of Ophthalmology, Faculty of Brain Sciences, University College London, 11-43 Bath St, London EC1V 9EL, UK
| | - Peter Robinson
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Dr., Farmington, CT 06032, USA
| | | | - Meredith Wilson
- Department of Clinical Genetics, The Children's Hospital at Westmead, Sydney, Australia
| | - Suzanne Crowley
- Department of Paediatrics, St George's Healthcare NHS Trust, London, UK
| | - Veronica Kinsler
- Department of Paediatric Dermatology, Great Ormond Street Hospital, The Francis Crick Institute, London, UK
| | - Anna-Maria Ewins
- Haematology/Oncology Department, Royal Hospital for Sick Children, Glasgow, UK
| | - Pradeepa M Madapura
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Manthan Patel
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Nikolas Pontikos
- Institute of Ophthalmology, Faculty of Brain Sciences, University College London, 11-43 Bath St, London EC1V 9EL, UK
| | - Veryan Codd
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Tom Vulliamy
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Inderjeet Dokal
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK; Barts Health NHS Trust, London, UK
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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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44
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Olson CL, Barbour AT, Wuttke DS. Filling in the blanks: how the C-strand catches up to the G-strand at replicating telomeres using CST. Nat Struct Mol Biol 2022; 29:730-733. [PMID: 35948770 DOI: 10.1038/s41594-022-00818-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Conner L Olson
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Alexandra T Barbour
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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45
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Structure of Tetrahymena telomerase-bound CST with polymerase α-primase. Nature 2022; 608:813-818. [PMID: 35831498 PMCID: PMC9728385 DOI: 10.1038/s41586-022-04931-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 06/06/2022] [Indexed: 02/03/2023]
Abstract
Telomeres are the physical ends of linear chromosomes. They are composed of short repeating sequences (such as TTGGGG in the G-strand for Tetrahymena thermophila) of double-stranded DNA with a single-strand 3' overhang of the G-strand and, in humans, the six shelterin proteins: TPP1, POT1, TRF1, TRF2, RAP1 and TIN21,2. TPP1 and POT1 associate with the 3' overhang, with POT1 binding the G-strand3 and TPP1 (in complex with TIN24) recruiting telomerase via interaction with telomerase reverse transcriptase5 (TERT). The telomere DNA ends are replicated and maintained by telomerase6, for the G-strand, and subsequently DNA polymerase α-primase7,8 (PolαPrim), for the C-strand9. PolαPrim activity is stimulated by the heterotrimeric complex CTC1-STN1-TEN110-12 (CST), but the structural basis of the recruitment of PolαPrim and CST to telomere ends remains unknown. Here we report cryo-electron microscopy (cryo-EM) structures of Tetrahymena CST in the context of the telomerase holoenzyme, in both the absence and the presence of PolαPrim, and of PolαPrim alone. Tetrahymena Ctc1 binds telomerase subunit p50, a TPP1 orthologue, on a flexible Ctc1 binding motif revealed by cryo-EM and NMR spectroscopy. The PolαPrim polymerase subunit POLA1 binds Ctc1 and Stn1, and its interface with Ctc1 forms an entry port for G-strand DNA to the POLA1 active site. We thus provide a snapshot of four key components that are required for telomeric DNA synthesis in a single active complex-telomerase-core ribonucleoprotein, p50, CST and PolαPrim-that provides insights into the recruitment of CST and PolαPrim and the handoff between G-strand and C-strand synthesis.
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46
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Knockout of Shelterin subunit genes in zebrafish results in distinct outcomes. Biochem Biophys Res Commun 2022; 617:22-29. [DOI: 10.1016/j.bbrc.2022.05.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022]
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47
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Structure of active human telomerase with telomere shelterin protein TPP1. Nature 2022; 604:578-583. [PMID: 35418675 PMCID: PMC9912816 DOI: 10.1038/s41586-022-04582-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/23/2022] [Indexed: 12/13/2022]
Abstract
Human telomerase is a RNA-protein complex that extends the 3' end of linear chromosomes by synthesizing multiple copies of the telomeric repeat TTAGGG1. Its activity is a determinant of cancer progression, stem cell renewal and cellular aging2-5. Telomerase is recruited to telomeres and activated for telomere repeat synthesis by the telomere shelterin protein TPP16,7. Human telomerase has a bilobal structure with a catalytic core ribonuclear protein and a H and ACA box ribonuclear protein8,9. Here we report cryo-electron microscopy structures of human telomerase catalytic core of telomerase reverse transcriptase (TERT) and telomerase RNA (TER (also known as hTR)), and of telomerase with the shelterin protein TPP1. TPP1 forms a structured interface with the TERT-unique telomerase essential N-terminal domain (TEN) and the telomerase RAP motif (TRAP) that are unique to TERT, and conformational dynamics of TEN-TRAP are damped upon TPP1 binding, defining the requirements for recruitment and activation. The structures further reveal that the elements of TERT and TER that are involved in template and telomeric DNA handling-including the TEN domain and the TRAP-thumb helix channel-are largely structurally homologous to those in Tetrahymena telomerase10, and provide unique insights into the mechanism of telomerase activity. The binding site of the telomerase inhibitor BIBR153211,12 overlaps a critical interaction between the TER pseudoknot and the TERT thumb domain. Numerous mutations leading to telomeropathies13,14 are located at the TERT-TER and TEN-TRAP-TPP1 interfaces, highlighting the importance of TER-TERT and TPP1 interactions for telomerase activity, recruitment and as drug targets.
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48
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Sekne Z, Ghanim GE, van Roon AMM, Nguyen THD. Structural basis of human telomerase recruitment by TPP1-POT1. Science 2022; 375:1173-1176. [PMID: 35201900 DOI: 10.1126/science.abn6840] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Telomerase maintains genome stability by extending the 3' telomeric repeats at eukaryotic chromosome ends, thereby counterbalancing progressive loss caused by incomplete genome replication. In mammals, telomerase recruitment to telomeres is mediated by TPP1, which assembles as a heterodimer with POT1. We report structures of DNA-bound telomerase in complex with TPP1 and with TPP1-POT1 at 3.2- and 3.9-angstrom resolution, respectively. Our structures define interactions between telomerase and TPP1-POT1 that are crucial for telomerase recruitment to telomeres. The presence of TPP1-POT1 stabilizes the DNA, revealing an unexpected path by which DNA exits the telomerase active site and a DNA anchor site on telomerase that is important for telomerase processivity. Our findings rationalize extensive prior genetic and biochemical findings and provide a framework for future mechanistic work on telomerase regulation.
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Affiliation(s)
- Zala Sekne
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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49
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Hong X, Wang L, Zhang K, Liu J, Liu JP. Molecular Mechanisms of Alveolar Epithelial Stem Cell Senescence and Senescence-Associated Differentiation Disorders in Pulmonary Fibrosis. Cells 2022; 11:cells11050877. [PMID: 35269498 PMCID: PMC8909789 DOI: 10.3390/cells11050877] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 02/04/2023] Open
Abstract
Pulmonary senescence is accelerated by unresolved DNA damage response, underpinning susceptibility to pulmonary fibrosis. Recently it was reported that the SARS-Cov-2 viral infection induces acute pulmonary epithelial senescence followed by fibrosis, although the mechanism remains unclear. Here, we examine roles of alveolar epithelial stem cell senescence and senescence-associated differentiation disorders in pulmonary fibrosis, exploring the mechanisms mediating and preventing pulmonary fibrogenic crisis. Notably, the TGF-β signalling pathway mediates alveolar epithelial stem cell senescence by mechanisms involving suppression of the telomerase reverse transcriptase gene in pulmonary fibrosis. Alternatively, telomere uncapping caused by stress-induced telomeric shelterin protein TPP1 degradation mediates DNA damage response, pulmonary senescence and fibrosis. However, targeted intervention of cellular senescence disrupts pulmonary remodelling and fibrosis by clearing senescent cells using senolytics or preventing senescence using telomere dysfunction inhibitor (TELODIN). Studies indicate that the development of senescence-associated differentiation disorders is reprogrammable and reversible by inhibiting stem cell replicative senescence in pulmonary fibrosis, providing a framework for targeted intervention of the molecular mechanisms of alveolar stem cell senescence and pulmonary fibrosis. Abbreviations: DPS, developmental programmed senescence; IPF, idiopathic pulmonary fibrosis; OIS, oncogene-induced replicative senescence; SADD, senescence-associated differentiation disorder; SALI, senescence-associated low-grade inflammation; SIPS, stress-induced premature senescence; TERC, telomerase RNA component; TERT, telomerase reverse transcriptase; TIFs, telomere dysfunction-induced foci; TIS, therapy-induced senescence; VIS, virus-induced senescence.
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Affiliation(s)
- Xiaojing Hong
- Institute of Ageing Research, Hangzhou Normal University School of Medicine, Hangzhou 311121, China; (X.H.); (L.W.); (K.Z.); (J.L.)
| | - Lihui Wang
- Institute of Ageing Research, Hangzhou Normal University School of Medicine, Hangzhou 311121, China; (X.H.); (L.W.); (K.Z.); (J.L.)
| | - Kexiong Zhang
- Institute of Ageing Research, Hangzhou Normal University School of Medicine, Hangzhou 311121, China; (X.H.); (L.W.); (K.Z.); (J.L.)
| | - Jun Liu
- Institute of Ageing Research, Hangzhou Normal University School of Medicine, Hangzhou 311121, China; (X.H.); (L.W.); (K.Z.); (J.L.)
| | - Jun-Ping Liu
- Institute of Ageing Research, Hangzhou Normal University School of Medicine, Hangzhou 311121, China; (X.H.); (L.W.); (K.Z.); (J.L.)
- Department of Immunology and Pathology, Monash University Faculty of Medicine, Prahran, VIC 3181, Australia
- Hudson Institute of Medical Research, Monash University Department of Molecular and Translational Science, Clayton, VIC 3168, Australia
- Correspondence:
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Lu R, Pickett HA. Telomeric replication stress: the beginning and the end for alternative lengthening of telomeres cancers. Open Biol 2022; 12:220011. [PMID: 35259951 PMCID: PMC8905155 DOI: 10.1098/rsob.220011] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Telomeres are nucleoprotein structures that cap the ends of linear chromosomes. Telomeric DNA comprises terminal tracts of G-rich tandem repeats, which are inherently difficult for the replication machinery to navigate. Structural aberrations that promote activation of the alternative lengthening of telomeres (ALT) pathway of telomere maintenance exacerbate replication stress at ALT telomeres, driving fork stalling and fork collapse. This form of telomeric DNA damage perpetuates recombination-mediated repair pathways and break-induced telomere synthesis. The relationship between replication stress and DNA repair is tightly coordinated for the purpose of regulating telomere length in ALT cells, but has been shown to be experimentally manipulatable. This raises the intriguing possibility that induction of replication stress can be used as a means to cause toxic levels of DNA damage at ALT telomeres, thereby selectively disrupting the viability of ALT cancers.
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Affiliation(s)
- Robert Lu
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Hilda A. Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
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