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Maksiutenko EM, Merkureva V, Barbitoff YA, Tsay VV, Aseev MV, Glotov AS, Glotov OS. Exome sequencing in extreme altitude mountaineers identifies pathogenic variants in RTEL1 and COL6A1 previously associated with respiratory failure. Physiol Rep 2024; 12:e16015. [PMID: 38653581 PMCID: PMC11039409 DOI: 10.14814/phy2.16015] [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: 12/14/2023] [Revised: 04/02/2024] [Accepted: 04/02/2024] [Indexed: 04/25/2024] Open
Abstract
Adaptation of humans to challenging environmental conditions, such as extreme temperature, malnutrition, or hypoxia, is an interesting phenomenon for both basic and applied research. Identification of the genetic factors contributing to human adaptation to these conditions enhances our understanding of the underlying molecular and physiological mechanisms. In our study, we analyzed the exomes of 22 high altitude mountaineers to uncover genetic variants contributing to hypoxic adaptation. To our surprise, we identified two putative loss-of-function variants, rs1385101139 in RTEL1 and rs1002726737 in COL6A1 in two extremely high altitude (personal record of more than 8500 m) professional climbers. Both variants can be interpreted as pathogenic according to medical geneticists' guidelines, and are linked to inherited conditions involving respiratory failure (late-onset pulmonary fibrosis and severe Ullrich muscular dystrophy for rs1385101139 and rs1002726737, respectively). Our results suggest that a loss of gene function may act as an important factor of human adaptation, which is corroborated by previous reports in other human subjects.
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Affiliation(s)
- Evgeniia M. Maksiutenko
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
| | - Valeriia Merkureva
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- CerbaLab Ltd.St. PetersburgRussia
| | - Yury A. Barbitoff
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- Department of Genetics and BiotechnologySt. Petersburg State UniversitySt. PetersburgRussia
| | - Victoria V. Tsay
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- CerbaLab Ltd.St. PetersburgRussia
- Department of Experimental Medical VirologyMolecular Genetics and Biobanking of Pediatric Research and Clinical Center for Infectious DiseasesSt. PetersburgRussia
| | - Mikhail V. Aseev
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- CerbaLab Ltd.St. PetersburgRussia
| | - Andrey S. Glotov
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- Department of Genetics and BiotechnologySt. Petersburg State UniversitySt. PetersburgRussia
| | - Oleg S. Glotov
- Department of Genomic MedicineD.O. Ott Research Institute of Obstetrics, Gynaecology, and ReproductologySt. PetersburgRussia
- Department of Experimental Medical VirologyMolecular Genetics and Biobanking of Pediatric Research and Clinical Center for Infectious DiseasesSt. PetersburgRussia
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Smoom R, May CL, Skordalakes E, Kaestner KH, Tzfati Y. Separation of telomere protection from length regulation by two different point mutations at amino acid 492 of RTEL1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582005. [PMID: 38464183 PMCID: PMC10925190 DOI: 10.1101/2024.02.26.582005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
RTEL1 is an essential DNA helicase that plays multiple roles in genome stability and telomere length regulation. A variant of RTEL1 with a lysine at position 492 is associated with short telomeres in Mus spretus , while a conserved methionine at this position is found in M. musculus, which has ultra-long telomeres. In humans, a missense mutation at this position ( RTEL1 M492I ) causes a fatal telomere biology disease termed Hoyeraal-Hreidarsson syndrome (HHS). We previously described a M. musculus mouse model termed 'Telomouse', in which changing methionine 492 to a lysine (M492K) shortened the telomeres to their length in humans. Here, we report on the derivation of a mouse strain carrying the M492I mutation, termed 'HHS mouse'. The HHS mouse telomeres are not as short as those of Telomice but nevertheless they display higher levels of telomeric DNA damage, fragility and recombination, associated with anaphase bridges and micronuclei. These observations indicate that the two mutations separate critical functions of RTEL1: M492K mainly reduces the telomere length setpoint, while M492I predominantly disrupts telomere protection. The two mouse models enable dissecting the mechanistic roles of RTEL1 and the different contributions of short telomeres and DNA damage to telomere biology diseases, genomic instability, cancer, and aging.
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Hourvitz N, Awad A, Tzfati Y. The many faces of the helicase RTEL1 at telomeres and beyond. Trends Cell Biol 2024; 34:109-121. [PMID: 37532653 DOI: 10.1016/j.tcb.2023.07.002] [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: 04/13/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 08/04/2023]
Abstract
Regulator of telomere elongation 1 (RTEL1) is known as a DNA helicase that is important for telomeres and genome integrity. However, the diverse phenotypes of RTEL1 dysfunction, the wide spectrum of symptoms caused by germline RTEL1 mutations, and the association of RTEL1 mutations with cancers suggest that RTEL1 is a complex machine that interacts with DNA, RNA, and proteins, and functions in diverse cellular pathways. We summarize the proposed functions of RTEL1 and discuss their implications for telomere maintenance. Studying RTEL1 is crucial for understanding the complex interplay between telomere maintenance and other nuclear pathways, and how compromising these pathways causes telomere biology diseases, various aging-associated pathologies, and cancer.
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Affiliation(s)
- Noa Hourvitz
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Aya Awad
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel.
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Ito M, Fujita Y, Shinohara A. Positive and negative regulators of RAD51/DMC1 in homologous recombination and DNA replication. DNA Repair (Amst) 2024; 134:103613. [PMID: 38142595 DOI: 10.1016/j.dnarep.2023.103613] [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: 08/02/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023]
Abstract
RAD51 recombinase plays a central role in homologous recombination (HR) by forming a nucleoprotein filament on single-stranded DNA (ssDNA) to catalyze homology search and strand exchange between the ssDNA and a homologous double-stranded DNA (dsDNA). The catalytic activity of RAD51 assembled on ssDNA is critical for the DNA-homology-mediated repair of DNA double-strand breaks in somatic and meiotic cells and restarting stalled replication forks during DNA replication. The RAD51-ssDNA complex also plays a structural role in protecting the regressed/reversed replication fork. Two types of regulators control RAD51 filament formation, stability, and dynamics, namely positive regulators, including mediators, and negative regulators, so-called remodelers. The appropriate balance of action by the two regulators assures genome stability. This review describes the roles of positive and negative RAD51 regulators in HR and DNA replication and its meiosis-specific homolog DMC1 in meiotic recombination. We also provide future study directions for a comprehensive understanding of RAD51/DMC1-mediated regulation in maintaining and inheriting genome integrity.
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Affiliation(s)
- Masaru Ito
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Yurika Fujita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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Schertzer M, Jullien L, Pinto AL, Calado RT, Revy P, Londoño-Vallejo A. Human RTEL1 Interacts with KPNB1 (Importin β) and NUP153 and Connects Nuclear Import to Nuclear Envelope Stability in S-Phase. Cells 2023; 12:2798. [PMID: 38132118 PMCID: PMC10741959 DOI: 10.3390/cells12242798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023] Open
Abstract
Regulator of TElomere Length Helicase 1 (RTEL1) is a helicase required for telomere maintenance and genome replication and repair. RTEL1 has been previously shown to participate in the nuclear export of small nuclear RNAs. Here we show that RTEL1 deficiency leads to a nuclear envelope destabilization exclusively in cells entering S-phase and in direct connection to origin firing. We discovered that inhibiting protein import also leads to similar, albeit non-cell cycle-related, nuclear envelope disruptions. Remarkably, overexpression of wild-type RTEL1, or of its C-terminal part lacking the helicase domain, protects cells against nuclear envelope anomalies mediated by protein import inhibition. We identified distinct domains in the C-terminus of RTEL1 essential for the interaction with KPNB1 (importin β) and NUP153, respectively, and we demonstrated that, on its own, the latter domain can promote the dynamic nuclear internalization of peptides that freely diffuse through the nuclear pore. Consistent with putative functions exerted in protein import, RTEL1 can be visualized on both sides of the nuclear pore using high-resolution microscopy. In all, our work points to an unanticipated, helicase-independent, role of RTEL1 in connecting both nucleocytoplasmic trafficking and nuclear envelope integrity to genome replication initiation in S-phase.
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Affiliation(s)
- Michael Schertzer
- Institut Curie, PSL Research University, CNRS, UMR3244, F-75005 Paris, France;
- Sorbonne Universités, CNRS, UMR3244, F-75005 Paris, France
| | - Laurent Jullien
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Contre le Cancer, F-75006 Paris, France; (L.J.); (P.R.)
- Paris Descartes–Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - André L. Pinto
- Department of Medical Imaging, Hematology, and Oncology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, Brazil; (A.L.P.); (R.T.C.)
| | - Rodrigo T. Calado
- Department of Medical Imaging, Hematology, and Oncology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, Brazil; (A.L.P.); (R.T.C.)
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Contre le Cancer, F-75006 Paris, France; (L.J.); (P.R.)
- Paris Descartes–Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - Arturo Londoño-Vallejo
- Institut Curie, PSL Research University, CNRS, UMR3244, F-75005 Paris, France;
- Sorbonne Universités, CNRS, UMR3244, F-75005 Paris, France
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Zhang T, Zhou C, Guo J, Chang J, Wu H, He J. RTEL1 gene polymorphisms and neuroblastoma risk in Chinese children. BMC Cancer 2023; 23:1145. [PMID: 38001404 PMCID: PMC10675872 DOI: 10.1186/s12885-023-11642-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
BACKGROUND Neuroblastoma, a neuroendocrine tumor originating from the sympathetic ganglia, is one of the most common malignancies in childhood. RTEL1 is critical in many fundamental cellular processes, such as DNA replication, DNA damage repair, genomic integrity, and telomere stability. Single nucleotide polymorphisms (SNPs) in the RTEL1 gene have been reported to confer susceptibility to multiple cancers, but their contributing roles in neuroblastoma remain unclear. METHODS We conducted a study on 402 neuroblastoma cases and 473 controls to assess the association between four RTEL1 SNPs (rs3761124 T>C, rs3848672 T>C, rs3208008 A>C and rs2297441 G>A) and neuroblastoma susceptibility. RESULTS Our results show that rs3848672 T>C is significantly associated with an increased risk of neuroblastoma [CC vs. TT/TC: adjusted odds ratio (OR)=1.39, 95% confidence interval (CI)=1.02-1.90, P=0.038]. The stratified analysis further indicated that boy carriers of the rs3848672 CC genotype had a higher risk of neuroblastoma, and all carriers had an increased risk of developing neuroblastoma of mediastinum origin. Moreover, the rs2297441 AA genotype increased neuroblastoma risk in girls and predisposed children to neuroblastoma arising from retroperitoneal. CONCLUSION Our study indicated that the rs3848672 CC and rs2297441 AA genotypes of the RTEL1 gene are significantly associated with an increased risk of neuroblastoma in Chinese children in a gender- and site-specific manner.
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Affiliation(s)
- Ting Zhang
- Department of Clinical Laboratory, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, 317500, Zhejiang, China
| | - Chunlei Zhou
- Department of Pathology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, Jiangsu, China
| | - Jiejie Guo
- Department of Clinical Laboratory, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, 317500, Zhejiang, China
| | - Jiamin Chang
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, 9 Jinsui Road, Guangzhou, 510623, Guangdong, China
| | - Haiyan Wu
- Department of Pathology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, Jiangsu, China.
| | - Jing He
- Department of Clinical Laboratory, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, 317500, Zhejiang, China.
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, 9 Jinsui Road, Guangzhou, 510623, Guangdong, China.
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7
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Smoom R, May CL, Ortiz V, Tigue M, Kolev HM, Rowe M, Reizel Y, Morgan A, Egyes N, Lichtental D, Skordalakes E, Kaestner KH, Tzfati Y. Telomouse-a mouse model with human-length telomeres generated by a single amino acid change in RTEL1. Nat Commun 2023; 14:6708. [PMID: 37872177 PMCID: PMC10593777 DOI: 10.1038/s41467-023-42534-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/14/2023] [Indexed: 10/25/2023] Open
Abstract
Telomeres, the ends of eukaryotic chromosomes, protect genome integrity and enable cell proliferation. Maintaining optimal telomere length in the germline and throughout life limits the risk of cancer and enables healthy aging. Telomeres in the house mouse, Mus musculus, are about five times longer than human telomeres, limiting the use of this common laboratory animal for studying the contribution of telomere biology to aging and cancer. We identified a key amino acid variation in the helicase RTEL1, naturally occurring in the short-telomere mouse species M. spretus. Introducing this variation into M. musculus is sufficient to reduce the telomere length set point in the germline and generate mice with human-length telomeres. While these mice are fertile and appear healthy, the regenerative capacity of their colonic epithelium is compromised. The engineered Telomouse reported here demonstrates a dominant role of RTEL1 in telomere length regulation and provides a unique model for aging and cancer.
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Affiliation(s)
- Riham Smoom
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Catherine Lee May
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Vivian Ortiz
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mark Tigue
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hannah M Kolev
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Melissa Rowe
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yitzhak Reizel
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Faculty of Biotechnology and Food Engineering, Technion, Haifa, 3200003, Israel
| | - Ashleigh Morgan
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nachshon Egyes
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Dan Lichtental
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Emmanuel Skordalakes
- Department of Pharmacology and Toxicology, Massey Cancer Center, Virginia Commonwealth University, 401 College St, Richmond, VA, 23298, USA
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
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Sato K, Knipscheer P. G-quadruplex resolution: From molecular mechanisms to physiological relevance. DNA Repair (Amst) 2023; 130:103552. [PMID: 37572578 DOI: 10.1016/j.dnarep.2023.103552] [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: 05/24/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/14/2023]
Abstract
Guanine-rich DNA sequences can fold into stable four-stranded structures called G-quadruplexes or G4s. Research in the past decade demonstrated that G4 structures are widespread in the genome and prevalent in regulatory regions of actively transcribed genes. The formation of G4s has been tightly linked to important biological processes including regulation of gene expression and genome maintenance. However, they can also pose a serious threat to genome integrity especially by impeding DNA replication, and G4-associated somatic mutations have been found accumulated in the cancer genomes. Specialised DNA helicases and single stranded DNA binding proteins that can resolve G4 structures play a crucial role in preventing genome instability. The large variety of G4 unfolding proteins suggest the presence of multiple G4 resolution mechanisms in cells. Recently, there has been considerable progress in our detailed understanding of how G4s are resolved, especially during DNA replication. In this review, we first discuss the current knowledge of the genomic G4 landscapes and the impact of G4 structures on DNA replication and genome integrity. We then describe the recent progress on the mechanisms that resolve G4 structures and their physiological relevance. Finally, we discuss therapeutic opportunities to target G4 structures.
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Affiliation(s)
- Koichi Sato
- Oncode Institute, Hubrecht Institute-KNAW & University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Puck Knipscheer
- Oncode Institute, Hubrecht Institute-KNAW & University Medical Center Utrecht, Utrecht, the Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands.
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Valeeva LR, Abdulkina LR, Agabekian IA, Shakirov EV. Telomere biology and ribosome biogenesis: structural and functional interconnections. Biochem Cell Biol 2023; 101:394-409. [PMID: 36989538 DOI: 10.1139/bcb-2022-0383] [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: 03/31/2023] Open
Abstract
Telomeres are nucleoprotein structures that play a pivotal role in the protection and maintenance of eukaryotic chromosomes. Telomeres and the enzyme telomerase, which replenishes telomeric DNA lost during replication, are important factors necessary to ensure continued cell proliferation. Cell proliferation is also dependent on proper and efficient protein synthesis, which is carried out by ribosomes. Mutations in genes involved in either ribosome biogenesis or telomere biology result in cellular abnormalities and can cause human genetic diseases, defined as ribosomopathies and telomeropathies, respectively. Interestingly, recent discoveries indicate that many of the ribosome assembly and rRNA maturation factors have additional noncanonical functions in telomere biology. Similarly, several key proteins and enzymes involved in telomere biology, including telomerase, have unexpected roles in rRNA transcription and maturation. These observations point to an intriguing cross-talk mechanism potentially explaining the multiple pleiotropic symptoms of mutations in many causal genes identified in various telomeropathy and ribosomopathy diseases. In this review, we provide a brief summary of eukaryotic telomere and rDNA loci structures, highlight several universal features of rRNA and telomerase biogenesis, evaluate intriguing interconnections between telomere biology and ribosome assembly, and conclude with an assessment of overlapping features of human diseases of telomeropathies and ribosomopathies.
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Affiliation(s)
- Liia R Valeeva
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
| | - Liliia R Abdulkina
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia
| | - Inna A Agabekian
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia
| | - Eugene V Shakirov
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
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10
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Shin U, Lee Y. Unraveling DNA Repair Processes In Vivo: Insights from Zebrafish Studies. Int J Mol Sci 2023; 24:13120. [PMID: 37685935 PMCID: PMC10487404 DOI: 10.3390/ijms241713120] [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: 07/21/2023] [Revised: 08/16/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The critical role of the DNA repair system in preserving the health and survival of living organisms is widely recognized as dysfunction within this system can result in a broad range of severe conditions, including neurodegenerative diseases, blood disorders, infertility, and cancer. Despite comprehensive research on the molecular and cellular mechanisms of DNA repair pathways, there remains a significant knowledge gap concerning these processes at an organismal level. The teleost zebrafish has emerged as a powerful model organism for investigating these intricate DNA repair mechanisms. Their utility arises from a combination of their well-characterized genomic information, the ability to visualize specific phenotype outcomes in distinct cells and tissues, and the availability of diverse genetic experimental approaches. In this review, we provide an in-depth overview of recent advancements in our understanding of the in vivo roles of DNA repair pathways. We cover a variety of critical biological processes including neurogenesis, hematopoiesis, germ cell development, tumorigenesis, and aging, with a specific emphasis on findings obtained from the use of zebrafish as a model system. Our comprehensive review highlights the importance of zebrafish in enhancing our understanding of the functions of DNA repair systems at the organismal level and paves the way for future investigations in this field.
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Affiliation(s)
- Unbeom Shin
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yoonsung Lee
- Clinical Research Institute, Kyung Hee University Hospital at Gangdong, School of Medicine, Kyung Hee University, Seoul 05278, Republic of Korea
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11
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Vijay Kumar MJ, Morales R, Tsvetkov AS. G-quadruplexes and associated proteins in aging and Alzheimer's disease. FRONTIERS IN AGING 2023; 4:1164057. [PMID: 37323535 PMCID: PMC10267416 DOI: 10.3389/fragi.2023.1164057] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
Aging is a prominent risk factor for many neurodegenerative disorders, such as Alzheimer's disease (AD). Alzheimer's disease is characterized by progressive cognitive decline, memory loss, and neuropsychiatric and behavioral symptoms, accounting for most of the reported dementia cases. This disease is now becoming a major challenge and burden on modern society, especially with the aging population. Over the last few decades, a significant understanding of the pathophysiology of AD has been gained by studying amyloid deposition, hyperphosphorylated tau, synaptic dysfunction, oxidative stress, calcium dysregulation, and neuroinflammation. This review focuses on the role of non-canonical secondary structures of DNA/RNA G-quadruplexes (G4s, G4-DNA, and G4-RNA), G4-binding proteins (G4BPs), and helicases, and their roles in aging and AD. Being critically important for cellular function, G4s are involved in the regulation of DNA and RNA processes, such as replication, transcription, translation, RNA localization, and degradation. Recent studies have also highlighted G4-DNA's roles in inducing DNA double-strand breaks that cause genomic instability and G4-RNA's participation in regulating stress granule formation. This review emphasizes the significance of G4s in aging processes and how their homeostatic imbalance may contribute to the pathophysiology of AD.
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Affiliation(s)
- M. J. Vijay Kumar
- The Department of Neurology, The University of Texas McGovern Medical School at Houston, Houston, TX, United States
| | - Rodrigo Morales
- The Department of Neurology, The University of Texas McGovern Medical School at Houston, Houston, TX, United States
- Centro Integrativo de Biologia y Quimica Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago, Chile
| | - Andrey S. Tsvetkov
- The Department of Neurology, The University of Texas McGovern Medical School at Houston, Houston, TX, United States
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, United States
- UTHealth Consortium on Aging, The University of Texas McGovern Medical School, Houston, TX, United States
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12
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Emmenecker C, Mézard C, Kumar R. Repair of DNA double-strand breaks in plant meiosis: role of eukaryotic RecA recombinases and their modulators. PLANT REPRODUCTION 2023; 36:17-41. [PMID: 35641832 DOI: 10.1007/s00497-022-00443-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Homologous recombination during meiosis is crucial for the DNA double-strand breaks (DSBs) repair that promotes the balanced segregation of homologous chromosomes and enhances genetic variation. In most eukaryotes, two recombinases RAD51 and DMC1 form nucleoprotein filaments on single-stranded DNA generated at DSB sites and play a central role in the meiotic DSB repair and genome stability. These nucleoprotein filaments perform homology search and DNA strand exchange to initiate repair using homologous template-directed sequences located elsewhere in the genome. Multiple factors can regulate the assembly, stability, and disassembly of RAD51 and DMC1 nucleoprotein filaments. In this review, we summarize the current understanding of the meiotic functions of RAD51 and DMC1 and the role of their positive and negative modulators. We discuss the current models and regulators of homology searches and strand exchange conserved during plant meiosis. Manipulation of these repair factors during plant meiosis also holds a great potential to accelerate plant breeding for crop improvements and productivity.
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Affiliation(s)
- Côme Emmenecker
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France
- University of Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Christine Mézard
- Institut Jean-Pierre Bourgin (IJPB), CNRS, Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
| | - Rajeev Kumar
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
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13
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Chen X, Hao Z, Pan H, Liu W, Lu L, Zhang M, He X, Yi H, Tang S. Relationship between common telomere length-related genetic variations, telomere length, and risk of antituberculosis drug-induced hepatotoxicity in Chinese Han population: As assessed for causality using the updated Roussel Uclaf Causality Assessment Method. Fundam Clin Pharmacol 2023. [PMID: 36855016 DOI: 10.1111/fcp.12885] [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: 10/24/2022] [Revised: 02/05/2023] [Accepted: 02/15/2023] [Indexed: 03/02/2023]
Abstract
Antituberculosis drug-induced hepatotoxicity (ATDH) is a significant threat to tuberculosis control, and two recent studies indicated that leukocyte telomere length (LTL) might be a potential biomarker for ATDH. This study aimed to investigate the relationship between common telomere length-related genetic variations, LTL, and risk of ATDH in Eastern Chinese antituberculosis treatment patients. A 1:4 matched case-control study was conducted among 79 ATDH cases assessed for causality using the updated RUCAM and 316 controls. LTL was determined by quantitative real-time PCR, and nine SNPs involved in telomere biology reported by previous GWAS were assessed. Conditional logistic regression model was used to estimate the association between genotypes and risk of ATDH with odds ratios (ORs) and 95% confidence intervals (CIs). The average RUCAM score of cases was 7.1. The average LTL in cases was significantly shorter than that in controls (median = 1.239 vs. 1.481, P = 0.032). Differences in the distribution of LTL were statistically significant among three genotypes of SNP rs2736098 (CC vs. CT vs. TT, median = 1.544 vs. 1.356 vs. 1.337, P = 0.026) and rs2853677 (AA vs. AG vs. GG, median = 1.511 vs. 1.544 vs. 1.159, P = 0.005) in TERT. SNP rs7675998 in NAF1 was statistically associated with the risk of ATDH under the dominant model (adjusted OR = 1.725, 95% CI: 1.021-2.913, P = 0.042). This is the first study to investigate the relationship of LTL, common telomere length-related variations, and risk of ATDH. SNP rs2736098 and rs2853677 in TERT were significantly associated with LTL, and SNP rs7675998 in NAF1 may be associated with ATDH in Chinese population.
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Affiliation(s)
- Xinyu Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Zhuolu Hao
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Hongqiu Pan
- Department of Tuberculosis, The Third People's Hospital of Zhenjiang Affiliated to Jiangsu University, Zhenjiang, China
| | - Wenpei Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Lihuan Lu
- Department of Tuberculosis, The Second People's Hospital of Changshu, Changshu, China
| | - Meiling Zhang
- Department of Infectious Disease, The Jurong Hospital Affiliated to Jiangsu University, Jurong, China
| | - Xiaomin He
- Department of Infectious Disease, The People's Hospital of Taixing, Taixing, China
| | - Honggang Yi
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Shaowen Tang
- Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
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14
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Roles of G4-DNA and G4-RNA in Class Switch Recombination and Additional Regulations in B-Lymphocytes. Molecules 2023; 28:molecules28031159. [PMID: 36770824 PMCID: PMC9921937 DOI: 10.3390/molecules28031159] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
Mature B cells notably diversify immunoglobulin (Ig) production through class switch recombination (CSR), allowing the junction of distant "switch" (S) regions. CSR is initiated by activation-induced deaminase (AID), which targets cytosines adequately exposed within single-stranded DNA of transcribed targeted S regions, with a specific affinity for WRCY motifs. In mammals, G-rich sequences are additionally present in S regions, forming canonical G-quadruplexes (G4s) DNA structures, which favor CSR. Small molecules interacting with G4-DNA (G4 ligands), proved able to regulate CSR in B lymphocytes, either positively (such as for nucleoside diphosphate kinase isoforms) or negatively (such as for RHPS4). G4-DNA is also implicated in the control of transcription, and due to their impact on both CSR and transcriptional regulation, G4-rich sequences likely play a role in the natural history of B cell malignancies. Since G4-DNA stands at multiple locations in the genome, notably within oncogene promoters, it remains to be clarified how it can more specifically promote legitimate CSR in physiology, rather than pathogenic translocation. The specific regulatory role of G4 structures in transcribed DNA and/or in corresponding transcripts and recombination hereby appears as a major issue for understanding immune responses and lymphomagenesis.
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15
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Petronek MS, Allen BG. Maintenance of genome integrity by the late-acting cytoplasmic iron-sulfur assembly (CIA) complex. Front Genet 2023; 14:1152398. [PMID: 36968611 PMCID: PMC10031043 DOI: 10.3389/fgene.2023.1152398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 02/24/2023] [Indexed: 03/29/2023] Open
Abstract
Iron-sulfur (Fe-S) clusters are unique, redox-active co-factors ubiquitous throughout cellular metabolism. Fe-S cluster synthesis, trafficking, and coordination result from highly coordinated, evolutionarily conserved biosynthetic processes. The initial Fe-S cluster synthesis occurs within the mitochondria; however, the maturation of Fe-S clusters culminating in their ultimate insertion into appropriate cytosolic/nuclear proteins is coordinated by a late-acting cytosolic iron-sulfur assembly (CIA) complex in the cytosol. Several nuclear proteins involved in DNA replication and repair interact with the CIA complex and contain Fe-S clusters necessary for proper enzymatic activity. Moreover, it is currently hypothesized that the late-acting CIA complex regulates the maintenance of genome integrity and is an integral feature of DNA metabolism. This review describes the late-acting CIA complex and several [4Fe-4S] DNA metabolic enzymes associated with maintaining genome stability.
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Hassani MA, Murid J, Yan J. Regulator of telomere elongation helicase 1 gene and its association with malignancy. Cancer Rep (Hoboken) 2022; 6:e1735. [PMID: 36253342 PMCID: PMC9875622 DOI: 10.1002/cnr2.1735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND With the progression of next-generation sequencing technologies, researchers have identified numerous variants of the regulator of telomere elongation helicase 1 (RTEL1) gene that are associated with a broad spectrum of phenotypic manifestations, including malignancies. At the molecular level, RTEL1 is involved in the regulation of the repair, replication, and transcription of deoxyribonucleic acid (DNA) and the maintenance of telomere length. RTEL1 can act both as a promotor and inhibitor of tumorigenesis. Here, we review the potential mechanisms implicated in the malignant transformation of tissues under conditions of RTEL1 deficiency or its aberrant overexpression. RECENT FINDINGS A major hemostatic challenge during RTEL1 dysfunction could arise from its unbalanced activity for unwinding guanine-rich quadruplex DNA (G4-DNA) structures. In contrast, RTEL1 deficiency leads to alterations in telomeric and genome-wide DNA maintenance mechanisms, ribonucleoprotein metabolism, and the creation of an inflammatory and immune-deficient microenvironment, all promoting malignancy. Additionally, we hypothesize that functionally similar molecules could act to compensate for the deteriorated functions of RTEL1, thereby facilitating the survival of malignant cells. On the contrary, RTEL1 over-expression was directed toward G4-unwinding, by promoting replication fork progression and maintaining intact telomeres, may facilitate malignant transformation and proliferation of various pre-malignant cellular compartments. CONCLUSIONS Therefore, restoring the equilibrium of RTEL1 functions could serve as a therapeutic approach for preventing and treating malignancies.
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Affiliation(s)
- Mohammad Arian Hassani
- Department of Hematology, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Dalian Key Laboratory of HematologySecond Hospital of Dalian Medical UniversityDalianChina,Department of Hematology, Endocrinology and Rheumatology, Ali Abad Teaching HospitalKabul University of Medical SciencesJamal menaKabulAfghanistan
| | - Jamshid Murid
- Department of Hematology, Endocrinology and Rheumatology, Ali Abad Teaching HospitalKabul University of Medical SciencesJamal menaKabulAfghanistan
| | - Jinsong Yan
- Department of Hematology, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Dalian Key Laboratory of HematologySecond Hospital of Dalian Medical UniversityDalianChina,Diamond Bay Institute of HematologySecond Hospital of Dalian Medical UniversityDalianChina
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17
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Kohzaki M. Mammalian Resilience Revealed by a Comparison of Human Diseases and Mouse Models Associated With DNA Helicase Deficiencies. Front Mol Biosci 2022; 9:934042. [PMID: 36032672 PMCID: PMC9403131 DOI: 10.3389/fmolb.2022.934042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/23/2022] [Indexed: 12/01/2022] Open
Abstract
Maintaining genomic integrity is critical for sustaining individual animals and passing on the genome to subsequent generations. Several enzymes, such as DNA helicases and DNA polymerases, are involved in maintaining genomic integrity by unwinding and synthesizing the genome, respectively. Indeed, several human diseases that arise caused by deficiencies in these enzymes have long been known. In this review, the author presents the DNA helicases associated with human diseases discovered to date using recent analyses, including exome sequences. Since several mouse models that reflect these human diseases have been developed and reported, this study also summarizes the current knowledge regarding the outcomes of DNA helicase deficiencies in humans and mice and discusses possible mechanisms by which DNA helicases maintain genomic integrity in mammals. It also highlights specific diseases that demonstrate mammalian resilience, in which, despite the presence of genomic instability, patients and mouse models have lifespans comparable to those of the general population if they do not develop cancers; finally, this study discusses future directions for therapeutic applications in humans that can be explored using these mouse models.
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Abstract
The number of (TTAGGG)n repeats at the ends of chromosomes is highly variable between individual chromosomes, between different cells and between species. Progressive loss of telomere repeats limits the proliferation of pre-malignant human cells but also contributes to aging by inducing apoptosis and senescence in normal cells. Despite enormous progress in understanding distinct pathways that result in loss and gain of telomeric DNA in different cell types, many questions remain. Further studies are needed to delineate the role of damage to telomeric DNA, replication errors, chromatin structure, liquid-liquid phase transition, telomeric transcripts (TERRA) and secondary DNA structures such as guanine quadruplex structures, R-loops and T-loops in inducing gains and losses of telomere repeats in different cell types. Limitations of current telomere length measurements techniques and differences in telomere biology between species and different cell types complicate generalizations about the role of telomeres in aging and cancer. Here some of the factors regulating the telomere length in embryonic and adult cells in mammals are discussed from a mechanistic and evolutionary perspective.
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Affiliation(s)
- Peter Lansdorp
- Terry Fox Laboratory, British Columbia (BC) Cancer Agency, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Peter Lansdorp,
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Shakirov EV, Chen JJL, Shippen DE. Plant telomere biology: The green solution to the end-replication problem. THE PLANT CELL 2022; 34:2492-2504. [PMID: 35511166 PMCID: PMC9252485 DOI: 10.1093/plcell/koac122] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/14/2022] [Indexed: 05/04/2023]
Abstract
Telomere maintenance is a fundamental cellular process conserved across all eukaryotic lineages. Although plants and animals diverged over 1.5 billion years ago, lessons learned from plants continue to push the boundaries of science, revealing detailed molecular mechanisms in telomere biology with broad implications for human health, aging biology, and stress responses. Recent studies of plant telomeres have unveiled unexpected divergence in telomere sequence and architecture, and the proteins that engage telomeric DNA and telomerase. The discovery of telomerase RNA components in the plant kingdom and some algae groups revealed new insight into the divergent evolution and the universal core of telomerase across major eukaryotic kingdoms. In addition, resources cataloging the abundant natural variation in Arabidopsis thaliana, maize (Zea mays), and other plants are providing unparalleled opportunities to understand the genetic networks that govern telomere length polymorphism and, as a result, are uncovering unanticipated crosstalk between telomeres, environmental factors, organismal fitness, and plant physiology. Here we recap current advances in plant telomere biology and put this field in perspective relative to telomere and telomerase research in other eukaryotic lineages.
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Affiliation(s)
- Eugene V Shakirov
- Department of Biological Sciences, College of Science, Marshall University, Huntington, West Virginia 25701, USA
| | - Julian J -L Chen
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, USA
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20
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Lansdorp PM. Sex differences in telomere length, lifespan, and embryonic dyskerin levels. Aging Cell 2022; 21:e13614. [PMID: 35441417 PMCID: PMC9124296 DOI: 10.1111/acel.13614] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/20/2022] [Accepted: 04/03/2022] [Indexed: 01/22/2023] Open
Abstract
Telomerase levels in most human cells are insufficient to prevent loss of telomeric DNA with each replication cycle. The resulting “Hayflick” limit may have allowed lifespan to increase by suppressing the development of tumors early in life be it at the expense of compromised cellular responses late in life. At any given age, the average telomere length in leukocytes shows considerably variation between individuals with females having, on average, longer telomeres than males. Sex differences in average telomere length are already present at birth and correspond to reported differences in the average life expectancy between the sexes. Levels of telomerase RNA and dyskerin, encoded by DKC1, are known to limit telomerase activity in embryonic stem cells. X‐linked DKC1 is expressed from both alleles in female embryo cells and higher levels of dyskerin and telomerase could elongate telomeres prior to embryo implantation. The hypothesis that embryonic telomerase levels set the stage for the sex differences in telomere length and lifespan deserves further study.
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Affiliation(s)
- Peter M. Lansdorp
- Terry Fox Laboratory BC Cancer Agency Vancouver BC Canada
- Department of Medical Genetics University of British Columbia Vancouver BC Canada
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21
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Yuan H, Wu Y, Wang J, Qin X, Huang Y, Yan L, Fana Y, Zedenius J, Juhlin CC, Larsson C, Lui WO, Xu D. Synergistic effects of telomerase reverse transcriptase and regulator of telomere elongation helicase 1 on aggressiveness and outcomes in adrenocortical carcinoma. Biomed Pharmacother 2022; 149:112796. [PMID: 35279598 DOI: 10.1016/j.biopha.2022.112796] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 11/16/2022] Open
Abstract
Adrenocortical carcinoma (ACC) is one of the deadliest endocrine malignancies and telomere maintenance by activated telomerase is critically required for ACC development and progression. Because telomerase reverse transcriptase (TERT) and regulator of telomere elongation helicase 1 (RTEL1) play key roles in telomere homeostasis, we determined their effect on ACC pathogenesis and outcomes. Analyses of TCGA and GEO datasets showed significantly higher expression of RTEL1 but not TERT in ACC tumors, compared to their benign or normal counterparts. Furthermore, gains/amplifications of both TERT and RTEL1 genes were widespread in ACC tumors and their expression correlated with their gene copy numbers. Higher expression of either TERT or RTEL1 was associated with shorter overall and progression-free survival (OS and PFS) in the TCGA ACC patient cohort, and higher levels of both TERT and RTEL1 mRNA predicted the shortest patient OS and PFS. However, multivariate analyses showed that only RTEL1 independently predicted patient OS and PFS. Gene set enrichment analysis further showed enrichments of wnt/β-catenin, MYC, glycolysis, MTOR, and DNA repair signaling pathways in ACC tumors expressing high TERT and RTEL1 mRNA levels. Taken together, TERT and RTEL1 promote ACC aggressiveness synergistically and may serve as prognostic factors and therapeutic targets for ACC.
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Affiliation(s)
- Huiyang Yuan
- Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Yujiao Wu
- Department of Medicine, Division of Hematology, Bioclinicum and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden
| | - Jing Wang
- Department of Urologic Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230036, China
| | - Xin Qin
- Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Yongsheng Huang
- Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Lei Yan
- Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China.
| | - Yidong Fana
- Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; Department of Medicine, Division of Hematology, Bioclinicum and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Urologic Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230036, China; Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Breast, Endocrine Tumors and Sarcoma, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Pathology and Cancer Diagnostics, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Oncology-Pathology, Karolinska Institutet and Karolinska University Hospital Solna, Bioclinicum, Stockholm SE-171 64, Sweden.
| | - Jan Zedenius
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Breast, Endocrine Tumors and Sarcoma, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden
| | - C Christofer Juhlin
- Department of Pathology and Cancer Diagnostics, Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden; Department of Oncology-Pathology, Karolinska Institutet and Karolinska University Hospital Solna, Bioclinicum, Stockholm SE-171 64, Sweden
| | - Catharina Larsson
- Department of Oncology-Pathology, Karolinska Institutet and Karolinska University Hospital Solna, Bioclinicum, Stockholm SE-171 64, Sweden
| | - Weng-Onn Lui
- Department of Oncology-Pathology, Karolinska Institutet and Karolinska University Hospital Solna, Bioclinicum, Stockholm SE-171 64, Sweden
| | - Dawei Xu
- Department of Medicine, Division of Hematology, Bioclinicum and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm SE-171 64, Sweden.
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22
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Sakellariou D, Bak ST, Isik E, Barroso SI, Porro A, Aguilera A, Bartek J, Janscak P, Peña-Diaz J. MutSβ regulates G4-associated telomeric R-loops to maintain telomere integrity in ALT cancer cells. Cell Rep 2022; 39:110602. [PMID: 35385755 DOI: 10.1016/j.celrep.2022.110602] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/17/2021] [Accepted: 03/10/2022] [Indexed: 12/24/2022] Open
Abstract
Up to 15% of human cancers maintain their telomeres through a telomerase-independent mechanism, termed "alternative lengthening of telomeres" (ALT) that relies on homologous recombination between telomeric sequences. Emerging evidence suggests that the recombinogenic nature of ALT telomeres results from the formation of RNA:DNA hybrids (R-loops) between telomeric DNA and the long-noncoding telomeric repeat-containing RNA (TERRA). Here, we show that the mismatch repair protein MutSβ, a heterodimer of MSH2 and MSH3 subunits, is enriched at telomeres in ALT cancer cells, where it prevents the accumulation of telomeric G-quadruplex (G4) structures and R-loops. Cells depleted of MSH3 display increased incidence of R-loop-dependent telomere fragility and accumulation of telomeric C-circles. We also demonstrate that purified MutSβ recognizes and destabilizes G4 structures in vitro. These data suggest that MutSβ destabilizes G4 structures in ALT telomeres to regulate TERRA R-loops, which is a prerequisite for maintenance of telomere integrity during ALT.
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Affiliation(s)
- Despoina Sakellariou
- Center for Healthy Aging, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark; Danish Cancer Society Research Center, 2100 Copenhagen, Denmark
| | - Sara Thornby Bak
- Center for Healthy Aging, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Esin Isik
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zürich, Switzerland
| | - Sonia I Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, University of Seville-CSIC-UPO, Seville, Spain
| | - Antonio Porro
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zürich, Switzerland
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, University of Seville-CSIC-UPO, Seville, Spain
| | - Jiri Bartek
- Danish Cancer Society Research Center, 2100 Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, 17177 Stockholm, Sweden; Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 14300 Prague, Czech Republic
| | - Pavel Janscak
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zürich, Switzerland; Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 14300 Prague, Czech Republic.
| | - Javier Peña-Diaz
- Center for Healthy Aging, Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen, Denmark.
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23
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Campitelli BE, Razzaque S, Barbero B, Abdulkina LR, Hall MH, Shippen DE, Juenger TE, Shakirov EV. Plasticity, pleiotropy and fitness trade-offs in Arabidopsis genotypes with different telomere lengths. THE NEW PHYTOLOGIST 2022; 233:1939-1952. [PMID: 34826163 PMCID: PMC9218941 DOI: 10.1111/nph.17880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/14/2021] [Indexed: 05/12/2023]
Abstract
Telomere length has been implicated in the organismal response to stress, but the underlying mechanisms are unknown. Here we examine the impact of telomere length changes on the responses to three contrasting abiotic environments in Arabidopsis, and measure 32 fitness, developmental, physiological and leaf-level anatomical traits. We report that telomere length in wild-type and short-telomere mutants is resistant to abiotic stress, while the elongated telomeres in ku70 mutants are more plastic. We detected significant pleiotropic effects of telomere length on flowering time and key leaf physiological and anatomical traits. Furthermore, our data reveal a significant genotype by environment (G × E) interaction for reproductive fitness, with the benefits and costs to performance depending on the growth conditions. These results imply that life-history trade-offs between flowering time and reproductive fitness are impacted by telomere length variation. We postulate that telomere length in plants is subject to natural selection imposed by different environments.
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Affiliation(s)
- Brandon E. Campitelli
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
- Texas Institute for Discovery Education in Sciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Samsad Razzaque
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Borja Barbero
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - Liliia R. Abdulkina
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Republic of Tatarstan 420008, Russia
| | - Mitchell H. Hall
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
| | - Dorothy E. Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - Thomas E. Juenger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Eugene V. Shakirov
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Republic of Tatarstan 420008, Russia
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
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24
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Roger L, Tomas F, Gire V. Mechanisms and Regulation of Cellular Senescence. Int J Mol Sci 2021; 22:ijms222313173. [PMID: 34884978 PMCID: PMC8658264 DOI: 10.3390/ijms222313173] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/25/2021] [Accepted: 12/02/2021] [Indexed: 12/23/2022] Open
Abstract
Cellular senescence entails a state of an essentially irreversible proliferative arrest in which cells remain metabolically active and secrete a range of pro-inflammatory and proteolytic factors as part of the senescence-associated secretory phenotype. There are different types of senescent cells, and senescence can be induced in response to many DNA damage signals. Senescent cells accumulate in different tissues and organs where they have distinct physiological and pathological functions. Despite this diversity, all senescent cells must be able to survive in a nondividing state while protecting themselves from positive feedback loops linked to the constant activation of the DNA damage response. This capacity requires changes in core cellular programs. Understanding how different cell types can undergo extensive changes in their transcriptional programs, metabolism, heterochromatin patterns, and cellular structures to induce a common cellular state is crucial to preventing cancer development/progression and to improving health during aging. In this review, we discuss how senescent cells continuously evolve after their initial proliferative arrest and highlight the unifying features that define the senescent state.
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Affiliation(s)
- Lauréline Roger
- Structure and Instability of Genomes Laboratory, Muséum National d’Histoire Naturelle (MNHN), CNRS-UMR 7196/INSERM U1154, 43 Rue Cuvier, 75005 Paris, France;
| | - Fanny Tomas
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier, France;
| | - Véronique Gire
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier, France;
- Correspondence: ; Tel.: +33-(0)-434359513; Fax: +33-(0)-434359410
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Yang Y, Kong R, Goh FG, Somers WG, Hime GR, Li Z, Cai Y. dRTEL1 is essential for the maintenance of Drosophila male germline stem cells. PLoS Genet 2021; 17:e1009834. [PMID: 34644293 PMCID: PMC8513875 DOI: 10.1371/journal.pgen.1009834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 09/23/2021] [Indexed: 11/19/2022] Open
Abstract
Stem cells have the potential to maintain undifferentiated state and differentiate into specialized cell types. Despite numerous progress has been achieved in understanding stem cell self-renewal and differentiation, many fundamental questions remain unanswered. In this study, we identify dRTEL1, the Drosophila homolog of Regulator of Telomere Elongation Helicase 1, as a novel regulator of male germline stem cells (GSCs). Our genome-wide transcriptome analysis and ChIP-Seq results suggest that dRTEL1 affects a set of candidate genes required for GSC maintenance, likely independent of its role in DNA repair. Furthermore, dRTEL1 prevents DNA damage-induced checkpoint activation in GSCs. Finally, dRTEL1 functions to sustain Stat92E protein levels, the key player in GSC maintenance. Together, our findings reveal an intrinsic role of the DNA helicase dRTEL1 in maintaining male GSC and provide insight into the function of dRTEL1.
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Affiliation(s)
- Ying Yang
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Pathology, Peking University Health Science Center, Beijing, China
| | - Ruiyan Kong
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Feng Guang Goh
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
| | - W. Gregory Somers
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
| | - Gary R. Hime
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
| | - Zhouhua Li
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Yu Cai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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Sato K, Martin-Pintado N, Post H, Altelaar M, Knipscheer P. Multistep mechanism of G-quadruplex resolution during DNA replication. SCIENCE ADVANCES 2021; 7:eabf8653. [PMID: 34559566 PMCID: PMC8462899 DOI: 10.1126/sciadv.abf8653] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
G-quadruplex (or G4) structures form in guanine-rich DNA sequences and threaten genome stability when not properly resolved. G4 unwinding occurs during S phase via an unknown mechanism. Using Xenopus egg extracts, we define a three-step G4 unwinding mechanism that acts during DNA replication. First, the replicative helicase composed of Cdc45, MCM2-7 and GINS (CMG) stalls at a leading strand G4 structure. Second, the DEAH-box helicase 36 (DHX36) mediates bypass of the CMG past the intact G4 structure, allowing approach of the leading strand to the G4. Third, G4 structure unwinding by the Fanconi anemia complementation group J helicase (FANCJ) enables DNA polymerase to synthesize past the G4 motif. A G4 on the lagging strand template does not stall CMG but still requires DNA replication for unwinding. DHX36 and FANCJ have partially redundant roles, conferring pathway robustness. This previously unknown genome maintenance pathway promotes faithful G4 replication, thereby avoiding genome instability.
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Affiliation(s)
- Koichi Sato
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Uppsalalaan 8, Utrecht 3584 CT, Netherlands
| | - Nerea Martin-Pintado
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Uppsalalaan 8, Utrecht 3584 CT, Netherlands
| | - Harm Post
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, Netherlands
| | - Puck Knipscheer
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Uppsalalaan 8, Utrecht 3584 CT, Netherlands
- Corresponding author.
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Pavlova AV, Kubareva EA, Monakhova MV, Zvereva MI, Dolinnaya NG. Impact of G-Quadruplexes on the Regulation of Genome Integrity, DNA Damage and Repair. Biomolecules 2021; 11:1284. [PMID: 34572497 PMCID: PMC8472537 DOI: 10.3390/biom11091284] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/19/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022] Open
Abstract
DNA G-quadruplexes (G4s) are known to be an integral part of the complex regulatory systems in both normal and pathological cells. At the same time, the ability of G4s to impede DNA replication plays a critical role in genome integrity. This review summarizes the results of recent studies of G4-mediated genomic and epigenomic instability, together with associated DNA damage and repair processes. Although the underlying mechanisms remain to be elucidated, it is known that, among the proteins that recognize G4 structures, many are linked to DNA repair. We analyzed the possible role of G4s in promoting double-strand DNA breaks, one of the most deleterious DNA lesions, and their repair via error-prone mechanisms. The patterns of G4 damage, with a focus on the introduction of oxidative guanine lesions, as well as their removal from G4 structures by canonical repair pathways, were also discussed together with the effects of G4s on the repair machinery. According to recent findings, there must be a delicate balance between G4-induced genome instability and G4-promoted repair processes. A broad overview of the factors that modulate the stability of G4 structures in vitro and in vivo is also provided here.
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Affiliation(s)
- Anzhela V. Pavlova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
| | - Elena A. Kubareva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (E.A.K.); (M.V.M.)
| | - Mayya V. Monakhova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (E.A.K.); (M.V.M.)
| | - Maria I. Zvereva
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
| | - Nina G. Dolinnaya
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
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Multifunctionality of the Telomere-Capping Shelterin Complex Explained by Variations in Its Protein Composition. Cells 2021; 10:cells10071753. [PMID: 34359923 PMCID: PMC8305809 DOI: 10.3390/cells10071753] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/03/2021] [Accepted: 07/09/2021] [Indexed: 12/31/2022] Open
Abstract
Protecting telomere from the DNA damage response is essential to avoid the entry into cellular senescence and organismal aging. The progressive telomere DNA shortening in dividing somatic cells, programmed during development, leads to critically short telomeres that trigger replicative senescence and thereby contribute to aging. In several organisms, including mammals, telomeres are protected by a protein complex named Shelterin that counteract at various levels the DNA damage response at chromosome ends through the specific function of each of its subunits. The changes in Shelterin structure and function during development and aging is thus an intense area of research. Here, we review our knowledge on the existence of several Shelterin subcomplexes and the functional independence between them. This leads us to discuss the possibility that the multifunctionality of the Shelterin complex is determined by the formation of different subcomplexes whose composition may change during aging.
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Large-scale generation and phenotypic characterization of zebrafish CRISPR mutants of DNA repair genes. DNA Repair (Amst) 2021; 107:103173. [PMID: 34390914 DOI: 10.1016/j.dnarep.2021.103173] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/06/2021] [Indexed: 11/20/2022]
Abstract
A systematic knowledge of the roles of DNA repair genes at the level of the organism has been limited due to the lack of appropriate experimental approaches using animal model systems. Zebrafish has become a powerful vertebrate genetic model system with availability due to the ease of genome editing and large-scale phenotype screening. Here, we generated zebrafish mutants for 32 DNA repair and replication genes through multiplexed CRISPR/Cas9-mediated mutagenesis. Large-scale phenotypic characterization of our mutant collection revealed that three genes (atad5a, ddb1, pcna) are essential for proper embryonic development and hematopoiesis; seven genes (apex1, atrip, ino80, mre11a, shfm1, telo2, wrn) are required for growth and development during juvenile stage and six genes (blm, brca2, fanci, rad51, rad54l, rtel1) play critical roles in sex development. Furthermore, mutation in six genes (atad5a, brca2, polk, rad51, shfm1, xrcc1) displayed hypersensitivity to DNA damage agents. Our zebrafish mutant collection provides a unique resource for understanding of the roles of DNA repair genes at the organismal level.
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Shyian M, Shore D. Approaching Protein Barriers: Emerging Mechanisms of Replication Pausing in Eukaryotes. Front Cell Dev Biol 2021; 9:672510. [PMID: 34124054 PMCID: PMC8194067 DOI: 10.3389/fcell.2021.672510] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/03/2021] [Indexed: 11/13/2022] Open
Abstract
During nuclear DNA replication multiprotein replisome machines have to jointly traverse and duplicate the total length of each chromosome during each cell cycle. At certain genomic locations replisomes encounter tight DNA-protein complexes and slow down. This fork pausing is an active process involving recognition of a protein barrier by the approaching replisome via an evolutionarily conserved Fork Pausing/Protection Complex (FPC). Action of the FPC protects forks from collapse at both programmed and accidental protein barriers, thus promoting genome integrity. In addition, FPC stimulates the DNA replication checkpoint and regulates topological transitions near the replication fork. Eukaryotic cells have been proposed to employ physiological programmed fork pausing for various purposes, such as maintaining copy number at repetitive loci, precluding replication-transcription encounters, regulating kinetochore assembly, or controlling gene conversion events during mating-type switching. Here we review the growing number of approaches used to study replication pausing in vivo and in vitro as well as the characterization of additional factors recently reported to modulate fork pausing in different systems. Specifically, we focus on the positive role of topoisomerases in fork pausing. We describe a model where replisome progression is inherently cautious, which ensures general preservation of fork stability and genome integrity but can also carry out specialized functions at certain loci. Furthermore, we highlight classical and novel outstanding questions in the field and propose venues for addressing them. Given how little is known about replisome pausing at protein barriers in human cells more studies are required to address how conserved these mechanisms are.
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Affiliation(s)
- Maksym Shyian
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - David Shore
- Department of Molecular Biology, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
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31
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RTEL1 influences the abundance and localization of TERRA RNA. Nat Commun 2021; 12:3016. [PMID: 34021146 PMCID: PMC8140157 DOI: 10.1038/s41467-021-23299-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 04/22/2021] [Indexed: 12/13/2022] Open
Abstract
Telomere repeat containing RNAs (TERRAs) are a family of long non-coding RNAs transcribed from the subtelomeric regions of eukaryotic chromosomes. TERRA transcripts can form R-loops at chromosome ends; however the importance of these structures or the regulation of TERRA expression and retention in telomeric R-loops remain unclear. Here, we show that the RTEL1 (Regulator of Telomere Length 1) helicase influences the abundance and localization of TERRA in human cells. Depletion of RTEL1 leads to increased levels of TERRA RNA while reducing TERRA-containing R loops at telomeres. In vitro, RTEL1 shows a strong preference for binding G-quadruplex structures which form in TERRA. This binding is mediated by the C-terminal region of RTEL1, and is independent of the RTEL1 helicase domain. RTEL1 binding to TERRA appears to be essential for cell viability, underscoring the importance of this function. Degradation of TERRA-containing R-loops by overexpression of RNAse H1 partially recapitulates the increased TERRA levels and telomeric instability associated with RTEL1 deficiency. Collectively, these data suggest that regulation of TERRA is a key function of the RTEL1 helicase, and that loss of that function may contribute to the disease phenotypes of patients with RTEL1 mutations. Long non coding RNA TERRA transcripts can form R-loops at chromosome ends. Here, the authors reveal a role for the helicase RTEL in affecting TERRA levels and localization.
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32
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Bonnell E, Pasquier E, Wellinger RJ. Telomere Replication: Solving Multiple End Replication Problems. Front Cell Dev Biol 2021; 9:668171. [PMID: 33869233 PMCID: PMC8047117 DOI: 10.3389/fcell.2021.668171] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/10/2021] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic genomes are highly complex and divided into linear chromosomes that require end protection from unwarranted fusions, recombination, and degradation in order to maintain genomic stability. This is accomplished through the conserved specialized nucleoprotein structure of telomeres. Due to the repetitive nature of telomeric DNA, and the unusual terminal structure, namely a protruding single stranded 3′ DNA end, completing telomeric DNA replication in a timely and efficient manner is a challenge. For example, the end replication problem causes a progressive shortening of telomeric DNA at each round of DNA replication, thus telomeres eventually lose their protective capacity. This phenomenon is counteracted by the recruitment and the activation at telomeres of the specialized reverse transcriptase telomerase. Despite the importance of telomerase in providing a mechanism for complete replication of telomeric ends, the majority of telomere replication is in fact carried out by the conventional DNA replication machinery. There is significant evidence demonstrating that progression of replication forks is hampered at chromosomal ends due to telomeric sequences prone to form secondary structures, tightly DNA-bound proteins, and the heterochromatic nature of telomeres. The telomeric loop (t-loop) formed by invasion of the 3′-end into telomeric duplex sequences may also impede the passage of replication fork. Replication fork stalling can lead to fork collapse and DNA breaks, a major cause of genomic instability triggered notably by unwanted repair events. Moreover, at chromosomal ends, unreplicated DNA distal to a stalled fork cannot be rescued by a fork coming from the opposite direction. This highlights the importance of the multiple mechanisms involved in overcoming fork progression obstacles at telomeres. Consequently, numerous factors participate in efficient telomeric DNA duplication by preventing replication fork stalling or promoting the restart of a stalled replication fork at telomeres. In this review, we will discuss difficulties associated with the passage of the replication fork through telomeres in both fission and budding yeasts as well as mammals, highlighting conserved mechanisms implicated in maintaining telomere integrity during replication, thus preserving a stable genome.
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Affiliation(s)
- Erin Bonnell
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Cancer Research Pavilion, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Emeline Pasquier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Cancer Research Pavilion, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Raymund J Wellinger
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Cancer Research Pavilion, Université de Sherbrooke, Sherbrooke, QC, Canada
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Lejault P, Mitteaux J, Sperti FR, Monchaud D. How to untie G-quadruplex knots and why? Cell Chem Biol 2021; 28:436-455. [PMID: 33596431 DOI: 10.1016/j.chembiol.2021.01.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/08/2020] [Accepted: 01/20/2021] [Indexed: 12/12/2022]
Abstract
For over two decades, the prime objective of the chemical biology community studying G-quadruplexes (G4s) has been to use chemicals to interact with and stabilize G4s in cells to obtain mechanistic interpretations. This strategy has been undoubtedly successful, as demonstrated by recent advances. However, these insights have also led to a fundamental rethinking of G4-targeting strategies: due to the prevalence of G4s in the human genome, transcriptome, and ncRNAome (collectively referred to as the G4ome), and their involvement in human diseases, should we continue developing G4-stabilizing ligands or should we invest in designing molecular tools to unfold G4s? Here, we first focus on how, when, and where G4s fold in cells; then, we describe the enzymatic systems that have evolved to counteract G4 folding and how they have been used as tools to manipulate G4s in cells; finally, we present strategies currently being implemented to devise new molecular G4 unwinding agents.
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Affiliation(s)
- Pauline Lejault
- Institut de Chimie Moléculaire de l'Université de Bourgogne, ICMUB CNRS UMR 6302, UBFC Dijon, France
| | - Jérémie Mitteaux
- Institut de Chimie Moléculaire de l'Université de Bourgogne, ICMUB CNRS UMR 6302, UBFC Dijon, France
| | - Francesco Rota Sperti
- Institut de Chimie Moléculaire de l'Université de Bourgogne, ICMUB CNRS UMR 6302, UBFC Dijon, France
| | - David Monchaud
- Institut de Chimie Moléculaire de l'Université de Bourgogne, ICMUB CNRS UMR 6302, UBFC Dijon, France.
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34
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Martins C, Jehangir M. A genomic glimpse of B chromosomes in cichlids. Genes Genomics 2021; 43:199-208. [PMID: 33547625 DOI: 10.1007/s13258-021-01049-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 01/25/2023]
Abstract
BACKGROUND B chromosomes (Bs) are extra karyotype elements in addition to A chromosomes and are found in all major eukaryotic taxa. Among hundreds of investigated species, cichlid fishes have emerged as an interesting group of model and have contributed to unravel the complex biology of B chromosome. OBJECTIVE We review the current state of knowledge on B chromosome investigation in cichlid fish and discuss the recent genomic advances over gene and sequences hunting on Bs and their impact on the current concept of B chromosomes. RESULTS The Bs of cichlids have been under the subject of classical cytogenetics and high scale DNA, RNA and epigenetics analysis and a list of B chromosome genes and functional sequences has been generated. B chromosomes of cichlids are restricted to females in some species and are enriched with genes, relics of genes, transposable elements and sequences transcribing for many significant biological functions. Diverse potentially functional sequences have been described in the B chromosome of cichlids and could influence important biological characteristics as well seems to affect transcription and epigenetic modifications of the whole genome. CONCLUSION One of the most enigmatic characteristics of Bs in cichlids is their genic content related to cell cycle and chromosome structure, and their influence over sex rates. The relationship of Bs with cell cycle and sex determination looks like to be connected with the drive of the Bs during cell divisions.
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Affiliation(s)
- Cesar Martins
- Department of Structural and Functional Biology, Institute of Biosciences at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil.
| | - Maryam Jehangir
- Department of Structural and Functional Biology, Institute of Biosciences at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil
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35
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Ruis P, Van Ly D, Borel V, Kafer GR, McCarthy A, Howell S, Blassberg R, Snijders AP, Briscoe J, Niakan KK, Marzec P, Cesare AJ, Boulton SJ. TRF2-independent chromosome end protection during pluripotency. Nature 2021; 589:103-109. [PMID: 33239783 PMCID: PMC7614352 DOI: 10.1038/s41586-020-2960-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022]
Abstract
Mammalian telomeres protect chromosome ends from aberrant DNA repair1. TRF2, a component of the telomere-specific shelterin protein complex, facilitates end protection through sequestration of the terminal telomere repeat sequence within a lariat T-loop structure2,3. Deleting TRF2 (also known as TERF2) in somatic cells abolishes T-loop formation, which coincides with telomere deprotection, chromosome end-to-end fusions and inviability3-9. Here we establish that, by contrast, TRF2 is largely dispensable for telomere protection in mouse pluripotent embryonic stem (ES) and epiblast stem cells. ES cell telomeres devoid of TRF2 instead activate an attenuated telomeric DNA damage response that lacks accompanying telomere fusions, and propagate for multiple generations. The induction of telomere dysfunction in ES cells, consistent with somatic deletion of Trf2 (also known as Terf2), occurs only following the removal of the entire shelterin complex. Consistent with TRF2 being largely dispensable for telomere protection specifically during early embryonic development, cells exiting pluripotency rapidly switch to TRF2-dependent end protection. In addition, Trf2-null embryos arrest before implantation, with evidence of strong DNA damage response signalling and apoptosis specifically in the non-pluripotent compartment. Finally, we show that ES cells form T-loops independently of TRF2, which reveals why TRF2 is dispensable for end protection during pluripotency. Collectively, these data establish that telomere protection is solved by distinct mechanisms in pluripotent and somatic tissues.
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Affiliation(s)
- Phil Ruis
- The Francis Crick Institute, London, UK
| | - David Van Ly
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia
- School of Medicine, The University of Notre Dame Australia, Sydney, New South Wales, Australia
| | | | - Georgia R Kafer
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia
| | | | | | | | | | | | | | | | - Anthony J Cesare
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Sydney, New South Wales, Australia.
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Wang T, Zhang Y, Cui B, Wang M, Li Y, Gao K. miR-4530 inhibits the malignant biological behaviors of human glioma cells by directly targeting RTEL1. Acta Biochim Biophys Sin (Shanghai) 2020; 52:1394-1403. [PMID: 33200790 DOI: 10.1093/abbs/gmaa126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Indexed: 11/14/2022] Open
Abstract
Human glioma is the most common primary brain tumor and is associated with high morbidity and mortality. Aberrant expressions of microRNAs (miRNAs) are involved in glioma progression. In the present study, we aimed to elucidate the roles of miR-4530 in the pathogenesis of gliomas. miR-4530 expression was examined in human glioma clinical tissues and cell lines including U251 and T98G. The target gene of miR-4530, RTEL1, was predicted with online tools and validated by luciferase reporter assay. Lentivirus infection, transfection of plasmids, and miRNA mimics were used to manipulate gene expression. Cell proliferation was determined using the CCK-8 method, and migration and invasion assays were determined with transwell experiments. Colony formation was measured by crystal violet staining, while apoptosis was determined by Annexin V/PI staining. The anti-tumor effects of miR-4530 were evaluated in nude mice xenografted using U251 cells. Our results showed that miR-4530 was significantly down-regulated in human glioma tissues and cell lines. miR-4530 over-expression inhibited the malignant behaviors of U251 and T98G cells, including reduced proliferation, diminished colony formation, migration and invasion, and increased apoptosis. Further mechanistic investigations revealed that RTEL1 is a direct functional target of miR-4530 in gliomas, and its over-expression remarkably reverses the effects of miR-4530 mimics on inhibiting these malignant behaviors. In addition, miR-4530 over-expression inhibited the growth of xenografted U251 glioma in nude mice. Therefore, miR-4530 acts as a tumor-suppressor gene and inhibits the malignant biological behaviors of human glioma cells, which is associated with directly targeting RTEL1. The miR-4530/RTEL1 axis is a potential therapeutic target for gliomas.
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Affiliation(s)
- Tuo Wang
- Department of Neurosurgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yan Zhang
- Department of Operation, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Bo Cui
- Department of Endocrinology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Maode Wang
- Department of Neurosurgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Ya Li
- Department of Anesthesia Surgery, Affiliated Baoji Hospital of Xi'an Medical University, Baoji 721006, China
| | - Ke Gao
- Department of Neurosurgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
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Abstract
In this perspective, we introduce shelterin and the mechanisms of ATM activation and NHEJ at telomeres, before discussing the following questions: How are t-loops proposed to protect chromosome ends and what is the evidence for this model? Can other models explain how TRF2 mediates end protection? Could t-loops be pathological structures? How is end protection achieved in pluripotent cells? What do the insights into telomere end protection in pluripotent cells mean for the t-loop model of end protection? Why might different cell states have evolved different mechanisms of end protection? Finally, we offer support for an updated t-loop model of end protection, suggesting that the data is supportive of a critical role for t-loops in protecting chromosome ends from NHEJ and ATM activation, but that other mechanisms are involved. Finally, we propose that t-loops are likely dynamic, rather than static, structures.
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Affiliation(s)
- Phil Ruis
- The Francis Crick Institute, London NW1 1AT, United Kingdom
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38
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Kotsantis P, Segura-Bayona S, Margalef P, Marzec P, Ruis P, Hewitt G, Bellelli R, Patel H, Goldstone R, Poetsch AR, Boulton SJ. RTEL1 Regulates G4/R-Loops to Avert Replication-Transcription Collisions. Cell Rep 2020; 33:108546. [PMID: 33357438 PMCID: PMC7773548 DOI: 10.1016/j.celrep.2020.108546] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/29/2020] [Accepted: 12/01/2020] [Indexed: 11/21/2022] Open
Abstract
Regulator of telomere length 1 (RTEL1) is an essential helicase that maintains telomere integrity and facilitates DNA replication. The source of replication stress in Rtel1-deficient cells remains unclear. Here, we report that loss of RTEL1 confers extensive transcriptional changes independent of its roles at telomeres. The majority of affected genes in Rtel1-/- cells possess G-quadruplex (G4)-DNA-forming sequences in their promoters and are similarly altered at a transcriptional level in wild-type cells treated with the G4-DNA stabilizer TMPyP4 (5,10,15,20-Tetrakis-(N-methyl-4-pyridyl)porphine). Failure to resolve G4-DNAs formed in the displaced strand of RNA-DNA hybrids in Rtel1-/- cells is suggested by increased R-loops and elevated transcription-replication collisions (TRCs). Moreover, removal of R-loops by RNaseH1 overexpression suppresses TRCs and alleviates the global replication defects observed in Rtel1-/- and Rtel1PIP_box knockin cells and in wild-type cells treated with TMPyP4. We propose that RTEL1 unwinds G4-DNA/R-loops to avert TRCs, which is important to prevent global deregulation in both transcription and DNA replication.
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Affiliation(s)
| | | | - Pol Margalef
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Paulina Marzec
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Phil Ruis
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Graeme Hewitt
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Harshil Patel
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Anna R Poetsch
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; UCL Genetics Institute, University College London, Gower Street, London WC1E 6BT, UK
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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Awad A, Glousker G, Lamm N, Tawil S, Hourvitz N, Smoom R, Revy P, Tzfati Y. Full length RTEL1 is required for the elongation of the single-stranded telomeric overhang by telomerase. Nucleic Acids Res 2020; 48:7239-7251. [PMID: 32542379 PMCID: PMC7367169 DOI: 10.1093/nar/gkaa503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 12/17/2022] Open
Abstract
Telomeres cap the ends of eukaryotic chromosomes and distinguish them from broken DNA ends to suppress DNA damage response, cell cycle arrest and genomic instability. Telomeres are elongated by telomerase to compensate for incomplete replication and nuclease degradation and to extend the proliferation potential of germ and stem cells and most cancers. However, telomeres in somatic cells gradually shorten with age, ultimately leading to cellular senescence. Hoyeraal-Hreidarsson syndrome (HHS) is characterized by accelerated telomere shortening and diverse symptoms including bone marrow failure, immunodeficiency, and neurodevelopmental defects. HHS is caused by germline mutations in telomerase subunits, factors essential for its biogenesis and recruitment to telomeres, and in the helicase RTEL1. While diverse phenotypes were associated with RTEL1 deficiency, the telomeric role of RTEL1 affected in HHS is yet unknown. Inducible ectopic expression of wild-type RTEL1 in patient fibroblasts rescued the cells, enabled telomerase-dependent telomere elongation and suppressed the abnormal cellular phenotypes, while silencing its expression resulted in gradual telomere shortening. Our observations reveal an essential role of the RTEL1 C-terminus in facilitating telomerase action at the telomeric 3′ overhang. Thus, the common etiology for HHS is the compromised telomerase action, resulting in telomere shortening and reduced lifespan of telomerase positive cells.
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Affiliation(s)
- Aya Awad
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Galina Glousker
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Noa Lamm
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Shadi Tawil
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Noa Hourvitz
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Riham Smoom
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer and Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
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40
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De Magis A, Götz S, Hajikazemi M, Fekete-Szücs E, Caterino M, Juranek S, Paeschke K. Zuo1 supports G4 structure formation and directs repair toward nucleotide excision repair. Nat Commun 2020; 11:3907. [PMID: 32764578 PMCID: PMC7413387 DOI: 10.1038/s41467-020-17701-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 07/14/2020] [Indexed: 01/02/2023] Open
Abstract
Nucleic acids can fold into G-quadruplex (G4) structures that can fine-tune biological processes. Proteins are required to recognize G4 structures and coordinate their function. Here we identify Zuo1 as a novel G4-binding protein in vitro and in vivo. In vivo in the absence of Zuo1 fewer G4 structures form, cell growth slows and cells become UV sensitive. Subsequent experiments reveal that these cellular changes are due to reduced levels of G4 structures. Zuo1 function at G4 structures results in the recruitment of nucleotide excision repair (NER) factors, which has a positive effect on genome stability. Cells lacking functional NER, as well as Zuo1, accumulate G4 structures, which become accessible to translesion synthesis. Our results suggest a model in which Zuo1 supports NER function and regulates the choice of the DNA repair pathway nearby G4 structures.
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Affiliation(s)
- Alessio De Magis
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Silvia Götz
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
- European Research Institute for the Biology of Ageing, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands
| | - Mona Hajikazemi
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Enikő Fekete-Szücs
- European Research Institute for the Biology of Ageing, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands
| | - Marco Caterino
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Stefan Juranek
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Katrin Paeschke
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
- European Research Institute for the Biology of Ageing, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
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41
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Björkman A, Johansen SL, Lin L, Schertzer M, Kanellis DC, Katsori AM, Christensen ST, Luo Y, Andersen JS, Elsässer SJ, Londono-Vallejo A, Bartek J, Schou KB. Human RTEL1 associates with Poldip3 to facilitate responses to replication stress and R-loop resolution. Genes Dev 2020; 34:1065-1074. [PMID: 32561545 PMCID: PMC7397856 DOI: 10.1101/gad.330050.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 05/18/2020] [Indexed: 02/07/2023]
Abstract
In this study from Björkman et al., the authors sought to understand how RTEL1 helicase preserves genomic stability during replication. They demonstrate that RTEL1 and the Polδ subunit Poldip3 form a complex and are mutually dependent in chromatin binding after replication stress, and loss of RTEL1 and Poldip3 leads to marked R-loop accumulation that is confined to sites of active replication, thus highlighting a previously unknown role of RTEL1 and Poldip3 in R-loop suppression at genomic regions where transcription and replication intersect. RTEL1 helicase is a component of DNA repair and telomere maintenance machineries. While RTEL1's role in DNA replication is emerging, how RTEL1 preserves genomic stability during replication remains elusive. Here we used a range of proteomic, biochemical, cell, and molecular biology and gene editing approaches to provide further insights into potential role(s) of RTEL1 in DNA replication and genome integrity maintenance. Our results from complementary human cell culture models established that RTEL1 and the Polδ subunit Poldip3 form a complex and are/function mutually dependent in chromatin binding after replication stress. Loss of RTEL1 and Poldip3 leads to marked R-loop accumulation that is confined to sites of active replication, enhances endogenous replication stress, and fuels ensuing genomic instability. The impact of depleting RTEL1 and Poldip3 is epistatic, consistent with our proposed concept of these two proteins operating in a shared pathway involved in DNA replication control under stress conditions. Overall, our data highlight a previously unsuspected role of RTEL1 and Poldip3 in R-loop suppression at genomic regions where transcription and replication intersect, with implications for human diseases including cancer.
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Affiliation(s)
- Andrea Björkman
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Søren L Johansen
- Department of Cell Biology and Physiology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, Aarhus 8200, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Mike Schertzer
- 3UMR 3244 (Telomere and Cancer Laboratory), Centre National de la Recherche Scientifique, Institut Curie, PSL Research University, Sorbonne Universités, Paris 75005, France
| | - Dimitris C Kanellis
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Anna-Maria Katsori
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Søren T Christensen
- Department of Cell Biology and Physiology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yonglun Luo
- Department of Biomedicine, Aarhus University, Aarhus 8200, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Simon J Elsässer
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Arturo Londono-Vallejo
- 3UMR 3244 (Telomere and Cancer Laboratory), Centre National de la Recherche Scientifique, Institut Curie, PSL Research University, Sorbonne Universités, Paris 75005, France
| | - Jiri Bartek
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden.,Danish Cancer Society Research Centre, DK-2100 Copenhagen, Denmark
| | - Kenneth B Schou
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
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42
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SLX4 interacts with RTEL1 to prevent transcription-mediated DNA replication perturbations. Nat Struct Mol Biol 2020; 27:438-449. [PMID: 32398829 DOI: 10.1038/s41594-020-0419-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 03/17/2020] [Indexed: 12/20/2022]
Abstract
The SLX4 tumor suppressor is a scaffold that plays a pivotal role in several aspects of genome protection, including homologous recombination, interstrand DNA crosslink repair and the maintenance of common fragile sites and telomeres. Here, we unravel an unexpected direct interaction between SLX4 and the DNA helicase RTEL1, which, until now, were viewed as having independent and antagonistic functions. We identify cancer and Hoyeraal-Hreidarsson syndrome-associated mutations in SLX4 and RTEL1, respectively, that abolish SLX4-RTEL1 complex formation. We show that both proteins are recruited to nascent DNA, tightly co-localize with active RNA pol II, and that SLX4, in complex with RTEL1, promotes FANCD2/RNA pol II co-localization. Importantly, disrupting the SLX4-RTEL1 interaction leads to DNA replication defects in unstressed cells, which are rescued by inhibiting transcription. Our data demonstrate that SLX4 and RTEL1 interact to prevent replication-transcription conflicts and provide evidence that this is independent of the nuclease scaffold function of SLX4.
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43
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Huselid E, Bunting SF. The Regulation of Homologous Recombination by Helicases. Genes (Basel) 2020; 11:genes11050498. [PMID: 32369918 PMCID: PMC7290689 DOI: 10.3390/genes11050498] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 11/16/2022] Open
Abstract
Homologous recombination is essential for DNA repair, replication and the exchange of genetic material between parental chromosomes during meiosis. The stages of recombination involve complex reorganization of DNA structures, and the successful completion of these steps is dependent on the activities of multiple helicase enzymes. Helicases of many different families coordinate the processing of broken DNA ends, and the subsequent formation and disassembly of the recombination intermediates that are necessary for template-based DNA repair. Loss of recombination-associated helicase activities can therefore lead to genomic instability, cell death and increased risk of tumor formation. The efficiency of recombination is also influenced by the ‘anti-recombinase’ effect of certain helicases, which can direct DNA breaks toward repair by other pathways. Other helicases regulate the crossover versus non-crossover outcomes of repair. The use of recombination is increased when replication forks and the transcription machinery collide, or encounter lesions in the DNA template. Successful completion of recombination in these situations is also regulated by helicases, allowing normal cell growth, and the maintenance of genomic integrity.
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44
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Zhao S, Wang F, Liu L. Alternative Lengthening of Telomeres (ALT) in Tumors and Pluripotent Stem Cells. Genes (Basel) 2019; 10:genes10121030. [PMID: 31835618 PMCID: PMC6947546 DOI: 10.3390/genes10121030] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/28/2019] [Accepted: 12/02/2019] [Indexed: 12/22/2022] Open
Abstract
A telomere consists of repeated DNA sequences (TTAGGG)n as part of a nucleoprotein structure at the end of the linear chromosome, and their progressive shortening induces DNA damage response (DDR) that triggers cellular senescence. The telomere can be maintained by telomerase activity (TA) in the majority of cancer cells (particularly cancer stem cells) and pluripotent stem cells (PSCs), which exhibit unlimited self-proliferation. However, some cells, such as telomerase-deficient cancer cells, can add telomeric repeats by an alternative lengthening of the telomeres (ALT) pathway, showing telomere length heterogeneity. In this review, we focus on the mechanisms of the ALT pathway and potential clinical implications. We also discuss the characteristics of telomeres in PSCs, thereby shedding light on the therapeutic significance of telomere length regulation in age-related diseases and regenerative medicine.
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Affiliation(s)
- Shuang Zhao
- College of Life Sciences, Nankai University, Tianjin 300071, China;
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Feng Wang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China;
| | - Lin Liu
- College of Life Sciences, Nankai University, Tianjin 300071, China;
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
- Correspondence:
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45
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Components of the ribosome biogenesis pathway underlie establishment of telomere length set point in Arabidopsis. Nat Commun 2019; 10:5479. [PMID: 31792215 PMCID: PMC6889149 DOI: 10.1038/s41467-019-13448-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022] Open
Abstract
Telomeres cap the physical ends of eukaryotic chromosomes to ensure complete DNA replication and genome stability. Heritable natural variation in telomere length exists in yeast, mice, plants and humans at birth; however, major effect loci underlying such polymorphism remain elusive. Here, we employ quantitative trait locus (QTL) mapping and transgenic manipulations to identify genes controlling telomere length set point in a multi-parent Arabidopsis thaliana mapping population. We detect several QTL explaining 63.7% of the total telomere length variation in the Arabidopsis MAGIC population. Loss-of-function mutants of the NOP2A candidate gene located inside the largest effect QTL and of two other ribosomal genes RPL5A and RPL5B establish a shorter telomere length set point than wild type. These findings indicate that evolutionarily conserved components of ribosome biogenesis and cell proliferation pathways promote telomere elongation. Major effect loci controlling natural, heritable variation in telomere length are not known. Here, the authors use QTL mapping and transgenic manipulations in Arabidopsis to implicate the rRNA-processing genes NOP2A and RPL5 in telomere length set point regulation in this model species.
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46
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Gutierrez‑Rodrigues F, Masri N, Chouery E, Diamond C, Jalkh N, Vicente A, Kajigaya S, Abillama F, Bejjani N, Serhal W, Calado RT, Young NS, Farhat H, Coussa ML. A novel homozygous RTEL1 variant in a consanguineous Lebanese family: phenotypic heterogeneity and disease anticipation. Hum Genet 2019; 138:1323-1330. [PMID: 31677132 PMCID: PMC9809984 DOI: 10.1007/s00439-019-02076-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/22/2019] [Indexed: 01/06/2023]
Abstract
Phenotypic heterogeneity is often observed in patients with telomeropathies caused by pathogenic variants in telomere biology genes. However, the roles of recessive variants in these different phenotypes are not fully characterized. Our goal is to describe the biological roles of a novel homozygous RTEL1 variant identified in a consanguineous Lebanese family with unusual presentation of telomeropathies. A proband was screened for germline variants in telomere biology genes by whole exome sequencing. Leukocytes' telomere length was measured in the proband and eight relatives. We identified a novel homozygous p.E665K RTEL1 variant in the proband, his mother, and seven siblings that associated with telomere shortening and a broad spectrum of clinical manifestations, ranging from mild unspecific findings to severe phenotypes. Consanguinity in at least three family generations led to increased frequency of the homozygous p.E665K variant in the youngest generation and progressive telomere shortening. The increased frequency of the homozygous RTEL1 variant due to consanguinity in this Lebanese family allowed us to infer novel behaviors of recessive RTEL1 variants, as the expressivity and penetrance of this gene are very heterogenous between inter- and intra-generations. Progressive telomere shortening was associated with disease anticipation, first reported in recessive autosomal telomeropathies. Both genetic testing and telomere length measurement were critical for the clinical diagnosis of this family with telomere diseases marked by phenotypic heterogeneity.
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Affiliation(s)
| | - Nohad Masri
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
| | - Eliane Chouery
- Unité de Génétique Médicale, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon
| | - Carrie Diamond
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD 20892-1202, USA
| | - Nadine Jalkh
- Unité de Génétique Médicale, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon
| | - Alana Vicente
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD 20892-1202, USA
| | - Sachiko Kajigaya
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD 20892-1202, USA
| | - Fayez Abillama
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
| | - Noha Bejjani
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
| | - Wassim Serhal
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
| | - Rodrigo T. Calado
- Department of Medical Imaging, Hematology, and Clinical Oncology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Neal S. Young
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD 20892-1202, USA
| | - Hussein Farhat
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
| | - Marie Louise Coussa
- LAU Gilbert and Rose-Marie Chagoury School of Medicine, LAUMC/RH, Zahar Street, Achrafieh, Beirut 1110, Lebanon
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47
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Lansdorp P, van Wietmarschen N. Helicases FANCJ, RTEL1 and BLM Act on Guanine Quadruplex DNA in Vivo. Genes (Basel) 2019; 10:genes10110870. [PMID: 31683575 PMCID: PMC6896191 DOI: 10.3390/genes10110870] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/29/2019] [Accepted: 10/29/2019] [Indexed: 02/03/2023] Open
Abstract
Guanine quadruplex (G4) structures are among the most stable secondary DNA structures that can form in vitro, and evidence for their existence in vivo has been steadily accumulating. Originally described mainly for their deleterious effects on genome stability, more recent research has focused on (potential) functions of G4 structures in telomere maintenance, gene expression, and other cellular processes. The combined research on G4 structures has revealed that properly regulating G4 DNA structures in cells is important to prevent genome instability and disruption of normal cell function. In this short review we provide some background and historical context of our work resulting in the identification of FANCJ, RTEL1 and BLM as helicases that act on G4 structures in vivo. Taken together these studies highlight important roles of different G4 DNA structures and specific G4 helicases at selected genomic locations and telomeres in regulating gene expression and maintaining genome stability.
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Affiliation(s)
- Peter Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, BC V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada.
- European Research Institute for the Biology of Ageing, University of Groningen, 9713 AV Groningen, The Netherlands.
| | - Niek van Wietmarschen
- European Research Institute for the Biology of Ageing, University of Groningen, 9713 AV Groningen, The Netherlands.
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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48
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DNA- and DNA-Protein-Crosslink Repair in Plants. Int J Mol Sci 2019; 20:ijms20174304. [PMID: 31484324 PMCID: PMC6747210 DOI: 10.3390/ijms20174304] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 12/12/2022] Open
Abstract
DNA-crosslinks are one of the most severe types of DNA lesions. Crosslinks (CLs) can be subdivided into DNA-intrastrand CLs, DNA-interstrand CLs (ICLs) and DNA-protein crosslinks (DPCs), and arise by various exogenous and endogenous sources. If left unrepaired before the cell enters S-phase, ICLs and DPCs pose a major threat to genomic integrity by blocking replication. In order to prevent the collapse of replication forks and impairment of cell division, complex repair pathways have emerged. In mammals, ICLs are repaired by the so-called Fanconi anemia (FA) pathway, which includes 22 different FANC genes, while in plants only a few of these genes are conserved. In this context, two pathways of ICL repair have been defined, each requiring the interaction of a helicase (FANCJB/RTEL1) and a nuclease (FAN1/MUS81). Moreover, homologous recombination (HR) as well as postreplicative repair factors are also involved. Although DPCs possess a comparable toxic potential to cells, it has only recently been shown that at least three parallel pathways for DPC repair exist in plants, defined by the protease WSS1A, the endonuclease MUS81 and tyrosyl-DNA phosphodiesterase 1 (TDP1). The importance of crosslink repair processes are highlighted by the fact that deficiencies in the respective pathways are associated with diverse hereditary disorders.
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49
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Rare variants and loci for age-related macular degeneration in the Ohio and Indiana Amish. Hum Genet 2019; 138:1171-1182. [PMID: 31367973 PMCID: PMC6745026 DOI: 10.1007/s00439-019-02050-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 07/21/2019] [Indexed: 01/10/2023]
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness in the world. While dozens of independent genomic variants are associated with AMD, about one-third of AMD heritability is still unexplained. To identify novel variants and loci for AMD, we analyzed Illumina HumanExome chip data from 87 Amish individuals with early or late AMD, 79 unaffected Amish individuals, and 15 related Amish individuals with unknown AMD affection status. We retained 37,428 polymorphic autosomal variants across 175 samples for association and linkage analyses. After correcting for multiple testing (n = 37,428), we identified four variants significantly associated with AMD: rs200437673 (LCN9, p = 1.50 × 10−11), rs151214675 (RTEL1, p = 3.18 × 10−8), rs140250387 (DLGAP1, p = 4.49 × 10−7), and rs115333865 (CGRRF1, p = 1.05 × 10−6). These variants have not been previously associated with AMD and are not in linkage disequilibrium with the 52 known AMD-associated variants reported by the International AMD Genomics Consortium based on physical distance. Genome-wide significant linkage peaks were observed on chromosomes 8q21.11–q21.13 (maximum recessive HLOD = 4.03) and 18q21.2–21.32 (maximum dominant HLOD = 3.87; maximum recessive HLOD = 4.27). These loci do not overlap with loci previously linked to AMD. Through gene ontology enrichment analysis with ClueGO in Cytoscape, we determined that several genes in the 1-HLOD support interval of the chromosome 8 locus are involved in fatty acid binding and triglyceride catabolic processes, and the 1-HLOD support interval of the linkage region on chromosome 18 is enriched in genes that participate in serine-type endopeptidase inhibitor activity and the positive regulation of epithelial to mesenchymal transition. These results nominate novel variants and loci for AMD that require further investigation.
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50
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Abstract
Many recent advances have emerged in the telomere and telomerase fields. This Timeline article highlights the key advances that have expanded our views on the mechanistic underpinnings of telomeres and telomerase and their roles in ageing and disease. Three decades ago, the classic view was that telomeres protected the natural ends of linear chromosomes and that telomerase was a specific telomere-terminal transferase necessary for the replication of chromosome ends in single-celled organisms. While this concept is still correct, many diverse fields associated with telomeres and telomerase have substantially matured. These areas include the discovery of most of the key molecular components of telomerase, implications for limits to cellular replication, identification and characterization of human genetic disorders that result in premature telomere shortening, the concept that inhibiting telomerase might be a successful therapeutic strategy and roles for telomeres in regulating gene expression. We discuss progress in these areas and conclude with challenges and unanswered questions in the field.
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Affiliation(s)
- Jerry W Shay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Woodring E Wright
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
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