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Rafat A, Dizaji Asl K, Mazloumi Z, Movassaghpour AA, Farahzadi R, Nejati B, Nozad Charoudeh H. Telomerase-based therapies in haematological malignancies. Cell Biochem Funct 2022; 40:199-212. [PMID: 35103334 DOI: 10.1002/cbf.3687] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/10/2022] [Indexed: 02/02/2023]
Abstract
Telomeres are specialized genetic structures present at the end of all eukaryotic linear chromosomes. They progressively get shortened after each cell division due to end replication problems. Telomere shortening (TS) and chromosomal instability cause apoptosis and massive cell death. Following oncogene activation and inactivation of tumour suppressor genes, cells acquire mechanisms such as telomerase expression and alternative lengthening of telomeres to maintain telomere length (TL) and prevent initiation of cellular senescence or apoptosis. Significant TS, telomerase activation and alteration in expression of telomere-associated proteins are frequent features of different haematological malignancies that reflect on the progression, response to therapy and recurrence of these diseases. Telomerase is a ribonucleoprotein enzyme that has a pivotal role in maintaining the TL. However, telomerase activity in most somatic cells is insufficient to prevent TS. In 85-90% of tumour cells, the critically short telomeric length is maintained by telomerase activation. Thus, overexpression of telomerase in most tumour cells is a potential target for cancer therapy. In this review, alteration of telomeres, telomerase and telomere-associated proteins in different haematological malignancies and related telomerase-based therapies are discussed.
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Affiliation(s)
- Ali Rafat
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Khadijeh Dizaji Asl
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Zeinab Mazloumi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Raheleh Farahzadi
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Babak Nejati
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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2
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Mojiri A, Walther BK, Jiang C, Matrone G, Holgate R, Xu Q, Morales E, Wang G, Gu J, Wang R, Cooke JP. Telomerase therapy reverses vascular senescence and extends lifespan in progeria mice. Eur Heart J 2021; 42:4352-4369. [PMID: 34389865 PMCID: PMC8603239 DOI: 10.1093/eurheartj/ehab547] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/29/2021] [Accepted: 08/12/2021] [Indexed: 12/28/2022] Open
Abstract
AIMS Hutchinson-Gilford progeria syndrome (HGPS) is an accelerated ageing syndrome associated with premature vascular disease and death due to heart attack and stroke. In HGPS a mutation in lamin A (progerin) alters nuclear morphology and gene expression. Current therapy increases the lifespan of these children only modestly. Thus, greater understanding of the underlying mechanisms of HGPS is required to improve therapy. Endothelial cells (ECs) differentiated from induced pluripotent stem cells (iPSCs) derived from these patients exhibit hallmarks of senescence including replication arrest, increased expression of inflammatory markers, DNA damage, and telomere erosion. We hypothesized that correction of shortened telomeres may reverse these measures of vascular ageing. METHODS AND RESULTS We generated ECs from iPSCs belonging to children with HGPS and their unaffected parents. Telomerase mRNA (hTERT) was used to treat HGPS ECs. Endothelial morphology and functions were assessed, as well as proteomic and transcriptional profiles with attention to inflammatory markers, DNA damage, and EC identity genes. In a mouse model of HGPS, we assessed the effects of lentiviral transfection of mTERT on measures of senescence, focusing on the EC phenotype in various organs. hTERT treatment of human HGPS ECs improved replicative capacity; restored endothelial functions such as nitric oxide generation, acetylated low-density lipoprotein uptake and angiogenesis; and reduced the elaboration of inflammatory cytokines. In addition, hTERT treatment improved cellular and nuclear morphology, in association with a normalization of the transcriptional profile, effects that may be mediated in part by a reduction in progerin expression and an increase in sirtuin 1 (SIRT1). Progeria mice treated with mTERT lentivirus manifested similar improvements, with a reduction in inflammatory and DNA damage markers and increased SIRT1 in their vasculature and other organs. Furthermore, mTERT therapy increased the lifespan of HGPS mice. CONCLUSION Vascular rejuvenation using telomerase mRNA is a promising approach for progeria and other age-related diseases.
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Affiliation(s)
- Anahita Mojiri
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Brandon K Walther
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell St., College Station, TX 77840, USA
| | - Chongming Jiang
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gianfranco Matrone
- British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Rhonda Holgate
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Qiu Xu
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Elisa Morales
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Guangyu Wang
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
- Center for Bioinformatics and Computational Biology, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Jianhua Gu
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Rongfu Wang
- Department of Medicine, and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - John P Cooke
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
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Schmidt J, Goergens J, Pochechueva T, Kotter A, Schwenzer N, Sitte M, Werner G, Altmüller J, Thiele H, Nürnberg P, Isensee J, Li Y, Müller C, Leube B, Reinhardt HC, Hucho T, Salinas G, Helm M, Jachimowicz RD, Wieczorek D, Kohl T, Lehnart SE, Yigit G, Wollnik B. Biallelic variants in YRDC cause a developmental disorder with progeroid features. Hum Genet 2021; 140:1679-1693. [PMID: 34545459 PMCID: PMC8553732 DOI: 10.1007/s00439-021-02347-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/13/2021] [Indexed: 12/28/2022]
Abstract
The highly conserved YrdC domain-containing protein (YRDC) interacts with the well-described KEOPS complex, regulating specific tRNA modifications to ensure accurate protein synthesis. Previous studies have linked the KEOPS complex to a role in promoting telomere maintenance and controlling genome integrity. Here, we report on a newborn with a severe neonatal progeroid phenotype including generalized loss of subcutaneous fat, microcephaly, growth retardation, wrinkled skin, renal failure, and premature death at the age of 12 days. By trio whole-exome sequencing, we identified a novel homozygous missense mutation, c.662T > C, in YRDC affecting an evolutionary highly conserved amino acid (p.Ile221Thr). Functional characterization of patient-derived dermal fibroblasts revealed that this mutation impairs YRDC function and consequently results in reduced t6A modifications of tRNAs. Furthermore, we established and performed a novel and highly sensitive 3-D Q-FISH analysis based on single-telomere detection to investigate the impact of YRDC on telomere maintenance. This analysis revealed significant telomere shortening in YRDC-mutant cells. Moreover, single-cell RNA sequencing analysis of YRDC-mutant fibroblasts revealed significant transcriptome-wide changes in gene expression, specifically enriched for genes associated with processes involved in DNA repair. We next examined the DNA damage response of patient’s dermal fibroblasts and detected an increased susceptibility to genotoxic agents and a global DNA double-strand break repair defect. Thus, our data suggest that YRDC may affect the maintenance of genomic stability. Together, our findings indicate that biallelic variants in YRDC result in a developmental disorder with progeroid features and might be linked to increased genomic instability and telomere shortening.
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Affiliation(s)
- Julia Schmidt
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany.
| | - Jonas Goergens
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Department I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Tatiana Pochechueva
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Annika Kotter
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Niko Schwenzer
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Maren Sitte
- NGS-Integrative Genomics Core Unit (NIG), Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Gesa Werner
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Core Facility Genomics, Charitéplatz 1, 10117, Berlin, Germany.,Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Jörg Isensee
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, University Hospital of Cologne, Cologne, Germany
| | - Yun Li
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany
| | - Christian Müller
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany
| | - Barbara Leube
- Institute of Human Genetics, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - H Christian Reinhardt
- Department of Hematology and Stem Cell Transplantation, University Hospital Essen, University Duisburg-Essen, German Cancer Consortium (DKTK Partner Site Essen), Essen, Germany
| | - Tim Hucho
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, University Hospital of Cologne, Cologne, Germany
| | - Gabriela Salinas
- NGS-Integrative Genomics Core Unit (NIG), Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Ron D Jachimowicz
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Department I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Dagmar Wieczorek
- Institute of Human Genetics, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Tobias Kohl
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, Göttingen, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site, Göttingen, Germany.,Collaborative Research Unit SFB 1002, University of Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.,Collaborative Research Unit SFB 1190, University of Göttingen, Göttingen, Germany.,Transatlantic Network of Excellence CURE-PLaN, Fondation Leducq, Paris, France
| | - Gökhan Yigit
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Heinrich-Düker-Weg 12, 37073, Göttingen, Germany. .,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
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Fouquerel E, Opresko P. Analysis of Telomere Length and Aberrations by Quantitative FISH. Methods Mol Biol 2020; 2102:237-249. [PMID: 31989559 DOI: 10.1007/978-1-0716-0223-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A key component of sustained cellular proliferation is the preservation of telomere integrity. Telomeres are nucleoprotein structures that cap and protect linear chromosomes. Their linearity and repetitive sequence represent a challenge for the replication machinery and cause telomere shortening, fragility, and losses. Here we describe the common technique of quantitative fluorescent in situ hybridization that allows for the scoring of telomere aberrations and measurement of telomere length directly on metaphase chromosomes through the use of highly specific peptide nucleic acid probes.
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Affiliation(s)
- Elise Fouquerel
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Patricia Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA.,UPMC Hillman Cancer Center, Pittsburgh, PA, USA
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5
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Essentiality of CTNNB1 in Malignant Transformation of Human Embryonic Stem Cells under Long-Term Suboptimal Conditions. Stem Cells Int 2020; 2020:5823676. [PMID: 33029148 PMCID: PMC7532415 DOI: 10.1155/2020/5823676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/14/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
Human embryonic stem cells (hESCs) gradually accumulate abnormal karyotypes during long-term suboptimal culture, which hinder their application in regenerative medicine. Previous studies demonstrated that the activation of CTNNB1 might be implicated in this process. Hence, the hESC line with stably silenced CTNNB1 was established to further explore the role of CTNNB1 in the malignant transformation of hESCs. It was shown to play a vital role in the maintenance of the physiological properties of stem cells, such as proliferation, migration, differentiation, and telomere regulation. Furthermore, the malignant transformation of hESCs was induced by continuous exposure to 0.001 μg/ml mitomycin C (MMC). The results showed that CTNNB1 and its target genes, including proto-oncogenes CCND1 and C-MYC, were aberrantly upregulated in hESCs after MMC treatment. Moreover, the high expression of CTNNB1 accelerated cell transition from G0/G1 phase to the S phase and stimulated the growth of cells containing breakage-fusion-bridge (BFB) cycles. Conversely, CTNNB1 silencing inhibited these effects and triggered a survival crisis. The current data indicated that CTNNB1 is intimately associated with the physiological properties of stem cells; however, the aberrant expression of CTNNB1 is involved in the malignant transformation of hESCs, which might advance the process by facilitating telomere-related unstable cell proliferation. Thus, the aberrant CTNNB1 level might serve as a potential biomarker for detecting the malignant transformation of hESCs.
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6
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de Pedro N, Díez M, García I, García J, Otero L, Fernández L, García B, González R, Rincón S, Pérez D, Rodríguez E, Segovia E, Najarro P. Analytical Validation of Telomere Analysis Technology® for the High-Throughput Analysis of Multiple Telomere-Associated Variables. Biol Proced Online 2020; 22:2. [PMID: 31956299 PMCID: PMC6961256 DOI: 10.1186/s12575-019-0115-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/23/2019] [Indexed: 02/07/2023] Open
Abstract
Background A large number of studies have suggested a correlation between the status of telomeres and disease risk. High-throughput quantitative fluorescence in situ hybridization (HT Q-FISH) is a highly accurate telomere measurement technique that can be applied to the study of large cell populations. Here we describe the analytical performance testing and validation of Telomere Analysis Technology (TAT®), a laboratory-developed HT Q-FISH-based methodology that includes HT imaging and software workflows that provide a highly detailed view of telomere populations. Methods TAT was developed for the analysis of telomeres in peripheral blood mononuclear cells (PBMCs). TAT was compared with Terminal Restriction Fragment (TRF) length analysis, and tested for accuracy, precision, limits of detection (LOD) and specificity, reportable range and reference range. Results Using 6 different lymphocyte cell lines, we found a high correlation between TAT and TRF for telomere length (R2 ≥ 0.99). The standard variation (assay error) of TAT was 454 base pairs, and the limit of detection of 800 base pairs. A standard curve was constructed to cover human median reportable range values and defined its lower limit at 4700 bp and upper limits at 14,400 bp. Using TAT, up to 223 telomere associated variables (TAVs) can be obtained from a single sample. A pilot, population study, of telomere analysis using TAT revealed high accuracy and reliability of the methodology. Conclusions Analytical validation of TAT shows that is a robust and reliable technique for the characterization of a detailed telomere profile in large cell populations. The combination of high-throughput imaging and software workflows allows for the collection of a large number of telomere-associated variables from each sample, which can then be used in epidemiological and clinical studies.
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Affiliation(s)
| | - María Díez
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | - Irene García
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | - Jorge García
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | | | | | | | - Rut González
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | - Sara Rincón
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | - Diego Pérez
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
| | | | | | - Pilar Najarro
- Life Length SL, Miguel Ángel 11, 28010 Madrid, Spain
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7
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Dodson LM, Baldan A, Nissbeck M, Gunja SMR, Bonnen PE, Aubert G, Birchansky S, Virtanen A, Bertuch AA. From incomplete penetrance with normal telomere length to severe disease and telomere shortening in a family with monoallelic and biallelic PARN pathogenic variants. Hum Mutat 2019; 40:2414-2429. [PMID: 31448843 DOI: 10.1002/humu.23898] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/24/2019] [Accepted: 08/19/2019] [Indexed: 12/21/2022]
Abstract
PARN encodes poly(A)-specific ribonuclease. Biallelic and monoallelic PARN variants are associated with Hoyeraal-Hreidarsson syndrome/dyskeratosis congenita and idiopathic pulmonary fibrosis (IPF), respectively. The molecular features associated with incomplete penetrance of PARN-associated IPF have not been described. We report a family with a rare missense, p.Y91C, and a novel insertion, p.(I274*), PARN variant. We found PARN p.Y91C had reduced deadenylase activity and the p.(I274*) transcript was depleted. Detailed analysis of the consequences of these variants revealed that, while PARN protein was lowest in the severely affected biallelic child who had the shortest telomeres, it was also reduced in his mother with the p.(I274*) variant but telomeres at the 50th percentile. Increased adenylation of telomerase RNA, human telomerase RNA, and certain small nucleolar RNAs, and impaired ribosomal RNA maturation were observed in cells derived from the severely affected biallelic carrier, but not in the other, less affected biallelic carrier, who had less severely shortened telomeres, nor in the monoallelic carriers who were unaffected and had telomeres ranging from the 1st to the 50th percentiles. We identified hsa-miR-202-5p as a potential negative regulator of PARN. We propose one or more genetic modifiers influence the impact of PARN variants on its targets and this underlies incomplete penetrance of PARN-associated disease.
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Affiliation(s)
- Lois M Dodson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Alessandro Baldan
- Department of Pediatrics, Hematology/Oncology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - Mikael Nissbeck
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Sethu M R Gunja
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Geraldine Aubert
- Repeat Diagnostics Inc., North Vancouver, British Columbia, Canada
| | - Sherri Birchansky
- Department of Radiology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
| | - Anders Virtanen
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Alison A Bertuch
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Hematology/Oncology, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas
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Verma P, Dilley RL, Zhang T, Gyparaki MT, Li Y, Greenberg RA. RAD52 and SLX4 act nonepistatically to ensure telomere stability during alternative telomere lengthening. Genes Dev 2019; 33:221-235. [PMID: 30692206 PMCID: PMC6362809 DOI: 10.1101/gad.319723.118] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 12/05/2018] [Indexed: 11/25/2022]
Abstract
Approximately 15% of cancers use homologous recombination for alternative lengthening of telomeres (ALT). How the initiating genomic lesions invoke homology-directed telomere synthesis remains enigmatic. Here, we show that distinct dependencies exist for telomere synthesis in response to replication stress or DNA double-strand breaks (DSBs). RAD52 deficiency reduced spontaneous telomeric DNA synthesis and replication stress-associated recombination in G2, concomitant with telomere shortening and damage. However, viability and proliferation remained unaffected, suggesting that alternative telomere recombination mechanisms compensate in the absence of RAD52. In agreement, RAD52 was dispensable for DSB-induced telomere synthesis. Moreover, a targeted CRISPR screen revealed that loss of the structure-specific endonuclease scaffold SLX4 reduced the proliferation of RAD52-null ALT cells. While SLX4 was dispensable for RAD52-mediated ALT telomere synthesis in G2, combined SLX4 and RAD52 loss resulted in elevated telomere loss, unresolved telomere recombination intermediates, and mitotic infidelity. These findings establish that RAD52 and SLX4 mediate distinct postreplicative DNA repair processes that maintain ALT telomere stability and cancer cell viability.
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Affiliation(s)
- Priyanka Verma
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Robert L Dilley
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tianpeng Zhang
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Melina T Gyparaki
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yiwen Li
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Roger A Greenberg
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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