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Ghosh S, Nguyen MT, Choi HE, Stahl M, Kühn AL, Van der Auwera S, Grabe HJ, Völzke H, Homuth G, Myers SA, Hogaboam CM, Noth I, Martinez FJ, Petsko GA, Glimcher LH. RIOK2 transcriptionally regulates TRiC and dyskerin complexes to prevent telomere shortening. Nat Commun 2024; 15:7138. [PMID: 39164231 PMCID: PMC11335878 DOI: 10.1038/s41467-024-51336-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 08/02/2024] [Indexed: 08/22/2024] Open
Abstract
Telomere shortening is a prominent hallmark of aging and is emerging as a characteristic feature of Myelodysplastic Syndromes (MDS) and Idiopathic Pulmonary Fibrosis (IPF). Optimal telomerase activity prevents progressive shortening of telomeres that triggers DNA damage responses. However, the upstream regulation of telomerase holoenzyme components remains poorly defined. Here, we identify RIOK2, a master regulator of human blood cell development, as a critical transcription factor for telomere maintenance. Mechanistically, loss of RIOK2 or its DNA-binding/transactivation properties downregulates mRNA expression of both TRiC and dyskerin complex subunits that impairs telomerase activity, thereby causing telomere shortening. We further show that RIOK2 expression is diminished in aged individuals and IPF patients, and it strongly correlates with shortened telomeres in MDS patient-derived bone marrow cells. Importantly, ectopic expression of RIOK2 alleviates telomere shortening in IPF patient-derived primary lung fibroblasts. Hence, increasing RIOK2 levels prevents telomere shortening, thus offering therapeutic strategies for telomere biology disorders.
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Affiliation(s)
- Shrestha Ghosh
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.
- Department of Immunology, Harvard Medical School, Boston, MA, USA.
| | - Mileena T Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
- Yale University, New Haven, CT, USA
| | - Ha Eun Choi
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Maximilian Stahl
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Annemarie Luise Kühn
- Department for Psychiatry and Psychotherapy, University Medicine Greifswald, Greifswald, Germany
| | - Sandra Van der Auwera
- Department for Psychiatry and Psychotherapy, University Medicine Greifswald, Greifswald, Germany
- German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald, Greifswald, Germany
| | - Hans J Grabe
- Department for Psychiatry and Psychotherapy, University Medicine Greifswald, Greifswald, Germany
- German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald, Greifswald, Germany
| | - Henry Völzke
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Greifswald, Greifswald, Germany
| | - Georg Homuth
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | | | - Cory M Hogaboam
- Women's Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Imre Noth
- Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | - Fernando J Martinez
- Division of Pulmonary and Critical Care Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Gregory A Petsko
- Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurie H Glimcher
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.
- Department of Immunology, Harvard Medical School, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
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Qin J, Garus A, Autexier C. The C-terminal extension of dyskerin is a dyskeratosis congenita mutational hotspot that modulates interaction with telomerase RNA and subcellular localization. Hum Mol Genet 2024; 33:318-332. [PMID: 37879098 PMCID: PMC10840380 DOI: 10.1093/hmg/ddad180] [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: 08/24/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
Dyskerin is a component of the human telomerase complex and is involved in stabilizing the human telomerase RNA (hTR). Many mutations in the DKC1 gene encoding dyskerin are found in X-linked dyskeratosis congenita (X-DC), a premature aging disorder and other related diseases. The C-terminal extension (CTE) of dyskerin contributes to its interaction with the molecular chaperone SHQ1 during the early stage of telomerase biogenesis. Disease mutations in this region were proposed to disrupt dyskerin-SHQ1 interaction and destabilize dyskerin, reducing hTR levels indirectly. However, biochemical evidence supporting this hypothesis is still lacking. In addition, the effects of many CTE disease mutations on hTR have not been examined. In this study, we tested eight dyskerin CTE variants and showed that they failed to maintain hTR levels. These mutants showed slightly reduced but not abolished interaction with SHQ1, and caused defective binding to hTR. Deletion of the CTE further reduced binding to hTR, and perturbed localization of dyskerin to the Cajal bodies and the nucleolus, and the interaction with TCAB1 as well as GAR1. Our findings suggest impaired dyskerin-hTR interaction in cells as a previously overlooked mechanism through which dyskerin CTE mutations cause X-DC and related telomere syndromes.
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Affiliation(s)
- Jian Qin
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, Quebec, QC H3A 0C7, Canada
- Lady Davis Institute, Jewish General Hospital, 3755 Chem, de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada
| | - Alexandre Garus
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, Quebec, QC H3A 0C7, Canada
- Lady Davis Institute, Jewish General Hospital, 3755 Chem, de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, Quebec, QC H3A 0C7, Canada
- Lady Davis Institute, Jewish General Hospital, 3755 Chem, de la Côte-Sainte-Catherine, Montréal, QC H3T 1E2, Canada
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Ghanim GE, Sekne Z, Balch S, van Roon AMM, Nguyen THD. 2.7 Å cryo-EM structure of human telomerase H/ACA ribonucleoprotein. Nat Commun 2024; 15:746. [PMID: 38272871 PMCID: PMC10811338 DOI: 10.1038/s41467-024-45002-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024] Open
Abstract
Telomerase is a ribonucleoprotein (RNP) enzyme that extends telomeric repeats at eukaryotic chromosome ends to counterbalance telomere loss caused by incomplete genome replication. Human telomerase is comprised of two distinct functional lobes tethered by telomerase RNA (hTR): a catalytic core, responsible for DNA extension; and a Hinge and ACA (H/ACA) box RNP, responsible for telomerase biogenesis. H/ACA RNPs also have a general role in pseudouridylation of spliceosomal and ribosomal RNAs, which is critical for the biogenesis of the spliceosome and ribosome. Much of our structural understanding of eukaryotic H/ACA RNPs comes from structures of the human telomerase H/ACA RNP. Here we report a 2.7 Å cryo-electron microscopy structure of the telomerase H/ACA RNP. The significant improvement in resolution over previous 3.3 Å to 8.2 Å structures allows us to uncover new molecular interactions within the H/ACA RNP. Many disease mutations are mapped to these interaction sites. The structure also reveals unprecedented insights into a region critical for pseudouridylation in canonical H/ACA RNPs. Together, our work advances understanding of telomerase-related disease mutations and the mechanism of pseudouridylation by eukaryotic H/ACA RNPs.
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Affiliation(s)
| | - Zala Sekne
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
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Pederiva C, Trevisan DM, Peirasmaki D, Chen S, Savage SA, Larsson O, Ule J, Baranello L, Agostini F, Farnebo M. Control of protein synthesis through mRNA pseudouridylation by dyskerin. SCIENCE ADVANCES 2023; 9:eadg1805. [PMID: 37506213 PMCID: PMC10381945 DOI: 10.1126/sciadv.adg1805] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 06/26/2023] [Indexed: 07/30/2023]
Abstract
Posttranscriptional modifications of mRNA have emerged as regulators of gene expression. Although pseudouridylation is the most abundant, its biological role remains poorly understood. Here, we demonstrate that the pseudouridine synthase dyskerin associates with RNA polymerase II, binds to thousands of mRNAs, and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a guide RNA with full complementarity. In cells lacking dyskerin, mRNA pseudouridylation is reduced, while at the same time, de novo protein synthesis is enhanced, indicating that this modification interferes with translation. Accordingly, mRNAs with fewer pseudouridines due to knockdown of dyskerin are translated more efficiently. Moreover, mRNA pseudouridylation is severely reduced in patients with dyskeratosis congenita caused by inherited mutations in the gene encoding dyskerin (i.e., DKC1). Our findings demonstrate that pseudouridylation by dyskerin modulates mRNA translatability, with important implications for both normal development and disease.
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Affiliation(s)
- Chiara Pederiva
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna 17165, Sweden
| | - Davide M. Trevisan
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge 14152, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna 17165, Sweden
| | - Shan Chen
- Department of Oncology and Pathology, Karolinska Institutet, Solna 17165, Sweden
- Science for Life Laboratory, Stockholm 17165, Sweden
| | - Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD 20852, USA
| | - Ola Larsson
- Department of Oncology and Pathology, Karolinska Institutet, Solna 17165, Sweden
- Science for Life Laboratory, Stockholm 17165, Sweden
| | - Jernej Ule
- The Francis Crick Institute, London NW1 1AT, UK
- UK Dementia Research Institute, King’s College London, London W1T 7NF, UK
- National Institute of Chemistry, 1001 Ljubljana, Slovenia
| | - Laura Baranello
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna 17165, Sweden
| | - Federico Agostini
- Science for Life Laboratory, Stockholm 17165, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna 17165, Sweden
| | - Marianne Farnebo
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna 17165, Sweden
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge 14152, Sweden
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Nelson N, Feurstein S, Niaz A, Truong J, Holien JK, Lucas S, Fairfax K, Dickinson J, Bryan TM. Functional genomics for curation of variants in telomere biology disorder associated genes: A systematic review. Genet Med 2023; 25:100354. [PMID: 36496180 DOI: 10.1016/j.gim.2022.11.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Patients with an underlying telomere biology disorder (TBD) have variable clinical presentations, and they can be challenging to diagnose clinically. A genomic diagnosis for patients presenting with TBD is vital for optimal treatment. Unfortunately, many variants identified during diagnostic testing are variants of uncertain significance. This complicates management decisions, delays treatment, and risks nonuptake of potentially curative therapies. Improved application of functional genomic evidence may reduce variants of uncertain significance classifications. METHODS We systematically searched the literature for published functional assays interrogating TBD gene variants. When possible, established likely benign/benign and likely pathogenic/pathogenic variants were used to estimate the assay sensitivity, specificity, positive predictive value, negative predictive value, and odds of pathogenicity. RESULTS In total, 3131 articles were screened and 151 met inclusion criteria. Sufficient data to enable a PS3/BS3 recommendation were available for TERT variants only. We recommend that PS3 and BS3 can be applied at a moderate and supportive level, respectively. PS3/BS3 application was limited by a lack of assay standardization and limited inclusion of benign variants. CONCLUSION Further assay standardization and assessment of benign variants are required for optimal use of the PS3/BS3 criterion for TBD gene variant classification.
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Affiliation(s)
- Niles Nelson
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia; Department of Molecular Medicine, The Royal Hobart Hospital, Hobart, Tasmania, Australia; Department of Molecular Haematology, The Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
| | - Simone Feurstein
- Section of Hematology, Oncology, and Rheumatology, Department of Internal Medicine, Heidelberg University Hospital, Heidelberg, Germany
| | - Aram Niaz
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, New South Wales, Australia
| | - Jia Truong
- School of Science, STEM College, RMIT University, Bundoora, Victoria, Australia
| | - Jessica K Holien
- School of Science, STEM College, RMIT University, Bundoora, Victoria, Australia
| | - Sionne Lucas
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Kirsten Fairfax
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Joanne Dickinson
- The Menzies Institute for Medical Research, College of Health and Medicine, The University of Tasmania, Hobart, Tasmania, Australia
| | - Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, New South Wales, Australia
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Batista LFZ, Dokal I, Parker R. Telomere biology disorders: time for moving towards the clinic? Trends Mol Med 2022; 28:882-891. [PMID: 36057525 PMCID: PMC9509473 DOI: 10.1016/j.molmed.2022.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 11/19/2022]
Abstract
Telomere biology disorders (TBDs) are a group of rare diseases caused by mutations that impair telomere maintenance. Mutations that cause reduced levels of TERC/hTR, the telomerase RNA component, are found in most TBD patients and include loss-of-function mutations in hTR itself, in hTR-binding proteins [NOP10, NHP2, NAF1, ZCCHC8, and dyskerin (DKC1)], and in proteins required for hTR processing (PARN). These patients show diverse clinical presentations that most commonly include bone marrow failure (BMF)/aplastic anemia (AA), pulmonary fibrosis, and liver cirrhosis. There are no curative therapies for TBD patients. An understanding of hTR biogenesis, maturation, and degradation has identified pathways and pharmacological agents targeting the poly(A) polymerase PAPD5, which adds 3'-oligoadenosine tails to hTR to promote hTR degradation, and TGS1, which modifies the 5'-cap structure of hTR to enhance degradation, as possible therapeutic approaches. Critical next steps will be clinical trials to establish the effectiveness and potential side effects of these compounds in TBD patients.
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Affiliation(s)
- Luis F Z Batista
- Department of Medicine, Washington University in St. Louis, St. Louis, MO, USA; Center for Genome Integrity, Washington University in St. Louis, St. Louis, MO, USA; Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, MO, USA.
| | - Inderjeet Dokal
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Roy Parker
- Department of Biochemistry and Biofrontiers Instiute, University of Colorado, Boulder, CO, USA; Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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7
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Nagpal N, Tai AK, Nandakumar J, Agarwal S. Domain specific mutations in dyskerin disrupt 3' end processing of scaRNA13. Nucleic Acids Res 2022; 50:9413-9425. [PMID: 36018809 PMCID: PMC9458449 DOI: 10.1093/nar/gkac706] [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: 12/06/2021] [Revised: 07/27/2022] [Accepted: 08/10/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in DKC1 (encoding dyskerin) cause telomere diseases including dyskeratosis congenita (DC) by decreasing steady-state levels of TERC, the non-coding RNA component of telomerase. How DKC1 mutations variably impact numerous other snoRNAs remains unclear, which is a barrier to understanding disease mechanisms in DC beyond impaired telomere maintenance. Here, using DC patient iPSCs, we show that mutations in the dyskerin N-terminal extension domain (NTE) dysregulate scaRNA13. In iPSCs carrying the del37L NTE mutation or engineered to carry NTE mutations via CRISPR/Cas9, but not in those with C-terminal mutations, we found scaRNA13 transcripts with aberrant 3' extensions, as seen when the exoribonuclease PARN is mutated in DC. Biogenesis of scaRNA13 was rescued by repair of the del37L DKC1 mutation by genome-editing, or genetic or pharmacological inactivation of the polymerase PAPD5, which counteracts PARN. Inspection of the human telomerase cryo-EM structure revealed that in addition to mediating intermolecular dyskerin interactions, the NTE interacts with terminal residues of the associated snoRNA, indicating a role for this domain in 3' end definition. Our results provide mechanistic insights into the interplay of dyskerin and the PARN/PAPD5 axis in the biogenesis and accumulation of snoRNAs beyond TERC, broadening our understanding of ncRNA dysregulation in human diseases.
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Affiliation(s)
- Neha Nagpal
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital; Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; Department of Pediatrics, Harvard Medical School; Manton Center for Orphan Disease Research; Harvard Initiative in RNA Medicine; Boston, MA, USA
| | - Albert K Tai
- Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
- Data Intensive Studies Center, Tufts University, Medford, MA, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Suneet Agarwal
- To whom correspondence should be addressed. Tel: +1 617 919 4610; Fax: +1 617 919 3359;
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Dyskerin Downregulation Can Induce ER Stress and Promote Autophagy via AKT-mTOR Signaling Deregulation. Biomedicines 2022; 10:biomedicines10051092. [PMID: 35625829 PMCID: PMC9138296 DOI: 10.3390/biomedicines10051092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/28/2022] [Accepted: 05/04/2022] [Indexed: 02/05/2023] Open
Abstract
Dyskerin is an evolutionarily conserved nucleolar protein implicated in a wide range of fundamental biological roles, including telomere maintenance and ribosome biogenesis. Germline mutations of DKC1, the human gene encoding dyskerin, cause the hereditary disorders known as X-linked dyskeratosis congenita (X-DC). Moreover, dyskerin is upregulated in several cancers. Due to the pleiotropic functions of dyskerin, the X-DC clinical features overlap with those of both telomeropathies and ribosomopathies. In this paper, we evaluate the telomerase-independent effects of dyskerin depletion on cellular physiology by using inducible DCK1 knockdown. This system allows the downregulation of DKC1 expression within a short timeframe. We report that, in these cellular systems, dyskerin depletion induces the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum, which in turn induces the activation of the PERK branch of the unfolded protein response. We also demonstrate that the PERK-eIF2a-ATF4-CHOP signaling pathway, activated by dyskerin downregulation, triggers a functional autophagic flux through the inhibition of the PI3K/AKT/mTOR pathway. By revealing a novel unpredicted connection between the loss of dyskerin, autophagy and UPR, our results establish a firm link between the lowering of dyskerin levels and the activation of the ER stress response, that plays a key role in the pathogenesis of several diseases.
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Ruiz A, Flores-Gonzalez J, Buendia-Roldan I, Chavez-Galan L. Telomere Shortening and Its Association with Cell Dysfunction in Lung Diseases. Int J Mol Sci 2021; 23:425. [PMID: 35008850 PMCID: PMC8745057 DOI: 10.3390/ijms23010425] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 01/10/2023] Open
Abstract
Telomeres are localized at the end of chromosomes to provide genome stability; however, the telomere length tends to be shortened with each cell division inducing a progressive telomere shortening (TS). In addition to age, other factors, such as exposure to pollutants, diet, stress, and disruptions in the shelterin protein complex or genes associated with telomerase induce TS. This phenomenon favors cellular senescence and genotoxic stress, which increases the risk of the development and progression of lung diseases such as idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, SARS-CoV-2 infection, and lung cancer. In an infectious environment, immune cells that exhibit TS are associated with severe lymphopenia and death, whereas in a noninfectious context, naïve T cells that exhibit TS are related to cancer progression and enhanced inflammatory processes. In this review, we discuss how TS modifies the function of the immune system cells, making them inefficient in maintaining homeostasis in the lung. Finally, we discuss the advances in drug and gene therapy for lung diseases where TS could be used as a target for future treatments.
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Affiliation(s)
| | | | | | - Leslie Chavez-Galan
- Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City 14080, Mexico; (A.R.); (J.F.-G.); (I.B.-R.)
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Garus A, Autexier C. Dyskerin: an essential pseudouridine synthase with multifaceted roles in ribosome biogenesis, splicing, and telomere maintenance. RNA (NEW YORK, N.Y.) 2021; 27:1441-1458. [PMID: 34556550 PMCID: PMC8594475 DOI: 10.1261/rna.078953.121] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Dyskerin and its homologs are ancient and conserved enzymes that catalyze the most common post-transcriptional modification found in cells, pseudouridylation. The resulting pseudouridines provide stability to RNA molecules and regulate ribosome biogenesis and splicing events. Dyskerin does not act independently-it is the core component of a protein heterotetramer, which associates with RNAs that contain the H/ACA motif. The variety of H/ACA RNAs that guide the function of this ribonucleoprotein (RNP) complex highlights the diversity of cellular processes in which dyskerin participates. When associated with small nucleolar (sno) RNAs, it regulates ribosomal (r) RNAs and ribosome biogenesis. By interacting with small Cajal body (sca) RNAs, it targets small nuclear (sn) RNAs to regulate pre-mRNA splicing. As a component of the telomerase holoenzyme, dyskerin binds to the telomerase RNA to modulate telomere maintenance. In a disease context, dyskerin malfunction can result in multiple detrimental phenotypes. Mutations in DKC1, the gene that encodes dyskerin, cause the premature aging syndrome X-linked dyskeratosis congenita (X-DC), a still incurable disorder that typically leads to bone marrow failure. In this review, we present the classical and most recent findings on this essential protein, discussing the evolutionary, structural, and functional aspects of dyskerin and the H/ACA RNP. The latest research underscores the role that dyskerin plays in the regulation of gene expression, translation efficiency, and telomere maintenance, along with the impacts that defective dyskerin has on aging, cell proliferation, haematopoietic potential, and cancer.
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Affiliation(s)
- Alexandre Garus
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
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11
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Kan G, Wang Z, Sheng C, Chen G, Yao C, Mao Y, Chen S. Dual Inhibition of DKC1 and MEK1/2 Synergistically Restrains the Growth of Colorectal Cancer Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004344. [PMID: 34026451 PMCID: PMC8132060 DOI: 10.1002/advs.202004344] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/28/2021] [Indexed: 05/09/2023]
Abstract
Colorectal cancer, one of the most commonly diagnosed cancers worldwide, is often accompanied by uncontrolled proliferation of tumor cells. Dyskerin pseudouridine synthase 1 (DKC1), screened using the genome-wide RNAi strategy, is a previously unidentified key regulator that promotes colorectal cancer cell proliferation. Enforced expression of DKC1, but not its catalytically inactive mutant D125A, accelerates cell growth in vitro and in vivo. DKC1 knockdown or its inhibitor pyrazofurin attenuates cell proliferation. Proteomics, RNA immunoprecipitation (RIP)-seq, and RNA decay analyses reveal that DKC1 binds to and stabilizes the mRNA of several ribosomal proteins (RPs), including RPL10A, RPL22L1, RPL34, and RPS3. DKC1 depletion significantly accelerates mRNA decay of these RPs, which mediates the oncogenic function of DKC1. Interestingly, these DKC1-regulated RPs also interact with HRAS and suppress the RAS/RAF/MEK/ERK pathway. Pyrazofurin and trametinib combination synergistically restrains colorectal cancer cell growth in vitro and in vivo. Furthermore, DKC1 is markedly upregulated in colorectal cancer tissues compared to adjacent normal tissues. Colorectal cancer patients with higher DKC1 expression has consistently poorer overall survival and progression-free survival outcomes. Taken together, these data suggest that DKC1 is an essential gene and candidate therapeutic target for colorectal cancer.
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Affiliation(s)
- Guangyan Kan
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Ziyang Wang
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Chunjie Sheng
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Gong Chen
- Department of Colorectal SurgeryState Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Chen Yao
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Yizhi Mao
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
| | - Shuai Chen
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouGuangdong510060P. R. China
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SUMOylation- and GAR1-Dependent Regulation of Dyskerin Nuclear and Subnuclear Localization. Mol Cell Biol 2021; 41:MCB.00464-20. [PMID: 33526451 DOI: 10.1128/mcb.00464-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 01/20/2021] [Indexed: 12/29/2022] Open
Abstract
The nuclear and subnuclear compartmentalization of the telomerase-associated protein and H/ACA ribonucleoprotein component dyskerin is an important although incompletely understood aspect of H/ACA ribonucleoprotein function. Four SUMOylation sites were previously identified in the C-terminal nuclear/nucleolar localization signal (N/NoLS) of dyskerin. We found that a cytoplasmic localized C-terminal truncation variant of dyskerin lacking most of the C-terminal N/NoLS represents an under-SUMOylated variant of dyskerin compared to wild-type dyskerin. We demonstrate that mimicking constitutive SUMOylation of dyskerin using a SUMO3 fusion construct can drive nuclear accumulation of this variant and that the SUMO site K467 in this N/NoLS is particularly important for the subnuclear localization of dyskerin to the nucleolus in a mature H/ACA complex assembly- and SUMO-dependent manner. We also characterize a novel SUMO-interacting motif in the mature H/ACA complex component GAR1 that mediates the interaction between dyskerin and GAR1. Mislocalization of dyskerin, either in the cytoplasm or excluded from the nucleolus, disrupts dyskerin function and leads to reduced interaction of dyskerin with the telomerase RNA. These data indicate a role for dyskerin C-terminal N/NoLS SUMOylation in regulating the nuclear and subnuclear localization of dyskerin, which is essential for dyskerin function as both a telomerase-associated protein and as an H/ACA ribonucleoprotein.
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13
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Chen L, Roake CM, Galati A, Bavasso F, Micheli E, Saggio I, Schoeftner S, Cacchione S, Gatti M, Artandi SE, Raffa GD. Loss of Human TGS1 Hypermethylase Promotes Increased Telomerase RNA and Telomere Elongation. Cell Rep 2021; 30:1358-1372.e5. [PMID: 32023455 PMCID: PMC7156301 DOI: 10.1016/j.celrep.2020.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/09/2019] [Accepted: 12/31/2019] [Indexed: 02/08/2023] Open
Abstract
Biogenesis of the human telomerase RNA (hTR) involves a complex series of posttranscriptional modifications, including hypermethylation of the 5' mono-methylguanosine cap to a tri-methylguanosine cap (TMG). How the TMG cap affects hTR maturation is unknown. Here, we show that depletion of trimethylguanosine synthase 1 (TGS1), the enzyme responsible for cap hypermethylation, increases levels of hTR and telomerase. Diminished trimethylation increases hTR association with the cap-binding complex (CBC) and with Sm chaperone proteins. Loss of TGS1 causes an increase in accumulation of mature hTR in both the nucleus and the cytoplasm compared with controls. In TGS1 mutant cells, increased hTR assembles with telomerase reverse transcriptase (TERT) protein to yield elevated active telomerase complexes and increased telomerase activity, resulting in telomere elongation in cultured human cells. Our results show that TGS1-mediated hypermethylation of the hTR cap inhibits hTR accumulation, restrains levels of assembled telomerase, and limits telomere elongation.
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Affiliation(s)
- Lu Chen
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Caitlin M Roake
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Francesca Bavasso
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Emanuela Micheli
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Isabella Saggio
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Stefan Schoeftner
- Cancer Epigenetic Group, Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie, Trieste, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy; Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Roma, Italy
| | - Steven E Artandi
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Grazia D Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy.
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14
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Qin J, Autexier C. Regulation of human telomerase RNA biogenesis and localization. RNA Biol 2021; 18:305-315. [PMID: 32813614 PMCID: PMC7954027 DOI: 10.1080/15476286.2020.1809196] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/03/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022] Open
Abstract
Maintenance of telomeres is essential for genome integrity and replicative capacity in eukaryotic cells. Telomerase, the ribonucleoprotein complex that catalyses telomere synthesis is minimally composed of a reverse transcriptase and an RNA component. The sequence and structural domains of human telomerase RNA (hTR) have been extensively characterized, while the regulation of hTR transcription, maturation, and localization, is not fully understood. Here, we provide an up-to-date review of hTR, with an emphasis on current breakthroughs uncovering the mechanisms of hTR maturation and localization.
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Affiliation(s)
- Jian Qin
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, Canada
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15
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Grill S, Nandakumar J. Molecular mechanisms of telomere biology disorders. J Biol Chem 2021; 296:100064. [PMID: 33482595 PMCID: PMC7948428 DOI: 10.1074/jbc.rev120.014017] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
Genetic mutations that affect telomerase function or telomere maintenance result in a variety of diseases collectively called telomeropathies. This wide spectrum of disorders, which include dyskeratosis congenita, pulmonary fibrosis, and aplastic anemia, is characterized by severely short telomeres, often resulting in hematopoietic stem cell failure in the most severe cases. Recent work has focused on understanding the molecular basis of these diseases. Mutations in the catalytic TERT and TR subunits of telomerase compromise activity, while others, such as those found in the telomeric protein TPP1, reduce the recruitment of telomerase to the telomere. Mutant telomerase-associated proteins TCAB1 and dyskerin and the telomerase RNA maturation component poly(A)-specific ribonuclease affect the maturation and stability of telomerase. In contrast, disease-associated mutations in either CTC1 or RTEL1 are more broadly associated with telomere replication defects. Yet even with the recent surge in studies decoding the mechanisms underlying these diseases, a significant proportion of dyskeratosis congenita mutations remain uncharacterized or poorly understood. Here we review the current understanding of the molecular basis of telomeropathies and highlight experimental data that illustrate how genetic mutations drive telomere shortening and dysfunction in these patients. This review connects insights from both clinical and molecular studies to create a comprehensive view of the underlying mechanisms that drive these diseases. Through this, we emphasize recent advances in therapeutics and pinpoint disease-associated variants that remain poorly defined in their mechanism of action. Finally, we suggest future avenues of research that will deepen our understanding of telomere biology and telomere-related disease.
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Affiliation(s)
- Sherilyn Grill
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA.
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16
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Kamal S, Junaid M, Ejaz A, Bibi I, Akash MSH, Rehman K. The secrets of telomerase: Retrospective analysis and future prospects. Life Sci 2020; 257:118115. [PMID: 32698073 DOI: 10.1016/j.lfs.2020.118115] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
Telomerase plays a significant role to maintain and regulate the telomere length, cellular immortality and senescence by the addition of guanine-rich repetitive sequences. Chronic inflammation or oxidative stress-induced infection downregulates TERT gene modifying telomerase activity thus contributing to the early steps of gastric carcinogenesis process. Furthermore, telomere-telomerase system performs fundamental role in the pathogenesis and progression of diabetes mellitus as well as in its vascular intricacy. The cessation of cell proliferation in cultured cells by inhibiting the telomerase activity of transformed cells renders the rationale for culling of telomerase as a target therapy for the treatment of metabolic disorders and various types of cancers. In this article, we have briefly described the role of immune system and malignant cells in the expression of telomerase with critical analysis on the gaps and potential for future studies. The key findings regarding the secrets of the telomerase summarized in this article will help in future treatment modalities for the prevention of various types of cancers and metabolic disorders notably diabetes mellitus.
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Affiliation(s)
- Shagufta Kamal
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Muhammad Junaid
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Arslan Ejaz
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Ismat Bibi
- Department of Chemistry, Islamia University, Bahawalpur, Pakistan
| | | | - Kanwal Rehman
- Department of Pharmacy, University of Agriculture, Faisalabad, Pakistan.
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17
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Bratkovič T, Božič J, Rogelj B. Functional diversity of small nucleolar RNAs. Nucleic Acids Res 2020; 48:1627-1651. [PMID: 31828325 PMCID: PMC7038934 DOI: 10.1093/nar/gkz1140] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/17/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022] Open
Abstract
Small nucleolar RNAs (snoRNAs) are short non-protein-coding RNAs with a long-recognized role in tuning ribosomal and spliceosomal function by guiding ribose methylation and pseudouridylation at targeted nucleotide residues of ribosomal and small nuclear RNAs, respectively. SnoRNAs are increasingly being implicated in regulation of new types of post-transcriptional processes, for example rRNA acetylation, modulation of splicing patterns, control of mRNA abundance and translational efficiency, or they themselves are processed to shorter stable RNA species that seem to be the principal or alternative bioactive isoform. Intriguingly, some display unusual cellular localization under exogenous stimuli, or tissue-specific distribution. Here, we discuss the new and unforeseen roles attributed to snoRNAs, focusing on the presumed mechanisms of action. Furthermore, we review the experimental approaches to study snoRNA function, including high resolution RNA:protein and RNA:RNA interaction mapping, techniques for analyzing modifications on targeted RNAs, and cellular and animal models used in snoRNA biology research.
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Affiliation(s)
- Tomaž Bratkovič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI1000 Ljubljana, Slovenia
| | - Janja Božič
- Jozef Stefan Institute, Department of Biotechnology, Jamova cesta 39, SI1000 Ljubljana, Slovenia.,Biomedical Research Institute BRIS, Puhova ulica 10, SI1000 Ljubljana, Slovenia
| | - Boris Rogelj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI1000 Ljubljana, Slovenia.,Jozef Stefan Institute, Department of Biotechnology, Jamova cesta 39, SI1000 Ljubljana, Slovenia.,Biomedical Research Institute BRIS, Puhova ulica 10, SI1000 Ljubljana, Slovenia.,University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, SI1000 Ljubljana, Slovenia
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Dyskerin Mutations Present in Dyskeratosis Congenita Patients Increase Oxidative Stress and DNA Damage Signalling in Dictyostelium Discoideum. Cells 2019; 8:cells8111406. [PMID: 31717312 PMCID: PMC6912284 DOI: 10.3390/cells8111406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/17/2022] Open
Abstract
Dyskerin is a protein involved in the formation of small nucleolar and small Cajal body ribonucleoproteins. These complexes participate in RNA pseudouridylation and are also components of the telomerase complex required for telomere elongation. Dyskerin mutations cause a rare disease, X-linked dyskeratosis congenita, with no curative treatment. The social amoeba Dictyostelium discoideum contains a gene coding for a dyskerin homologous protein. In this article D. discoideum mutant strains that have mutations corresponding to mutations found in dyskeratosis congenita patients are described. The phenotype of the mutant strains has been studied and no alterations were observed in pseudouridylation activity and telomere structure. Mutant strains showed increased proliferation on liquid culture but reduced growth feeding on bacteria. The results obtained indicated the existence of increased DNA damage response and reactive oxygen species, as also reported in human Dyskeratosis congenita cells and some other disease models. These data, together with the haploid character of D. discoideum vegetative cells, that resemble the genomic structure of the human dyskerin gene, located in the X chromosome, support the conclusion that D. discoideum can be a good model system for the study of this disease.
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