1
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Nitschke NJ, Jelsig AM, Lautrup C, Lundsgaard M, Severinsen MT, Cowland JB, Maroun LL, Andersen MK, Grønbæk K. Expanding the understanding of telomere biology disorder with reports from two families harboring variants in ZCCHC8 and TERC. Clin Genet 2024; 106:187-192. [PMID: 38606545 DOI: 10.1111/cge.14534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/04/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024]
Abstract
Telomere biology disorder (TBD) can present within a wide spectrum of symptoms ranging from severe congenital malformations to isolated organ dysfunction in adulthood. Diagnosing TBD can be challenging given the substantial variation in symptoms and age of onset across generations. In this report, we present two families, one with a pathogenic variant in ZCCHC8 and another with a novel variant in TERC. In the literature, only one family has previously been reported with a ZCCHC8 variant and TBD symptoms. This family had multiple occurrences of pulmonary fibrosis and one case of bone marrow failure. In this paper, we present a second family with the same ZCCHC8 variant (p.Pro186Leu) and symptoms of TBD including pulmonary fibrosis, hematological disease, and elevated liver enzymes. The suspicion of TBD was confirmed with the measurement of short telomeres in the proband. In another family, we report a novel likely pathogenic variant in TERC. Our comprehensive description encompasses hematological manifestations, as well as pulmonary and hepatic fibrosis. Notably, there are no other reports which associate this variant to disease. The families expand our understanding of the clinical implications and genetic causes of TBD.
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Affiliation(s)
- Nikolaj Juul Nitschke
- Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Anne Marie Jelsig
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Charlotte Lautrup
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
- Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Malene Lundsgaard
- Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark
| | - Marianne Tang Severinsen
- Department of Hematology, Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Jack Bernard Cowland
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lisa Leth Maroun
- Department of Pathology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mette Klarskov Andersen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kirsten Grønbæk
- Department of Hematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Davis JA, Chakrabarti K. Molecular and Evolutionary Analysis of RNA-Protein Interactions in Telomerase Regulation. Noncoding RNA 2024; 10:36. [PMID: 38921833 PMCID: PMC11206666 DOI: 10.3390/ncrna10030036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/30/2024] [Accepted: 06/10/2024] [Indexed: 06/27/2024] Open
Abstract
Telomerase is an enzyme involved in the maintenance of telomeres. Telomere shortening due to the end-replication problem is a threat to the genome integrity of all eukaryotes. Telomerase inside cells depends on a myriad of protein-protein and RNA-protein interactions to properly assemble and regulate the function of the telomerase holoenzyme. These interactions are well studied in model eukaryotes, like humans, yeast, and the ciliated protozoan known as Tetrahymena thermophila. Emerging evidence also suggests that deep-branching eukaryotes, such as the parasitic protist Trypanosoma brucei require conserved and novel RNA-binding proteins for the assembly and function of their telomerase. In this review, we will discuss telomerase regulatory pathways in the context of telomerase-interacting proteins, with special attention paid to RNA-binding proteins. We will discuss these interactors on an evolutionary scale, from parasitic protists to humans, to provide a broader perspective on the extensive role that protein-protein and RNA-protein interactions play in regulating telomerase activity in eukaryotes.
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Affiliation(s)
| | - Kausik Chakrabarti
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA;
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3
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Lee YH, Hass EP, Campodonico W, Lee YK, Lasda E, Shah J, Rinn J, Hwang T. Massively parallel dissection of RNA in RNA-protein interactions in vivo. Nucleic Acids Res 2024; 52:e48. [PMID: 38726866 PMCID: PMC11162807 DOI: 10.1093/nar/gkae334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/10/2024] [Accepted: 04/16/2024] [Indexed: 06/11/2024] Open
Abstract
Many of the biological functions performed by RNA are mediated by RNA-binding proteins (RBPs), and understanding the molecular basis of these interactions is fundamental to biology. Here, we present massively parallel RNA assay combined with immunoprecipitation (MPRNA-IP) for in vivo high-throughput dissection of RNA-protein interactions and describe statistical models for identifying RNA domains and parsing the structural contributions of RNA. By using custom pools of tens of thousands of RNA sequences containing systematically designed truncations and mutations, MPRNA-IP is able to identify RNA domains, sequences, and secondary structures necessary and sufficient for protein binding in a single experiment. We show that this approach is successful for multiple RNAs of interest, including the long noncoding RNA NORAD, bacteriophage MS2 RNA, and human telomerase RNA, and we use it to interrogate the hitherto unknown sequence or structural RNA-binding preferences of the DNA-looping factor CTCF. By integrating systematic mutation analysis with crosslinking immunoprecipitation, MPRNA-IP provides a novel high-throughput way to elucidate RNA-based mechanisms behind RNA-protein interactions in vivo.
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Affiliation(s)
- Yu Hsuan Lee
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Evan P Hass
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Will Campodonico
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Yong Kyu Lee
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Erika Lasda
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Jaynish S Shah
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - John L Rinn
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Taeyoung Hwang
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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4
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Chen B, Weng Y, Li M, Bian Z, Tao Y, Zhou W, Lu H, He S, Liao R, Huang J, Wang Q, Xu M, Ge Y, Cao W, Lei M, Zhang Y. LINC02454-CCT complex interaction is essential for telomerase activity and cell proliferation in head and neck squamous cell carcinoma. Cancer Lett 2024; 588:216734. [PMID: 38401886 DOI: 10.1016/j.canlet.2024.216734] [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: 10/27/2023] [Revised: 02/03/2024] [Accepted: 02/13/2024] [Indexed: 02/26/2024]
Abstract
Telomerase activity is upregulated in head and neck squamous cell carcinoma (HNSCC), yet its regulatory mechanisms remain unclear. Here, we identified a cancer-specific lncRNA (LINC02454) associated with poor prognosis by using LncRNA chip of our HNSCC cohorts and external datasets. Through employing negative-stain transmission electron microscopy (NS-TEM), we discovered an interaction between LINC02454 and CCT complex which would augment telomerase activity for maintaining telomere homeostasis. Supporting this, in the telomerase repeat amplification protocol (TRAP) assay and quantitative fluorescence in situ hybridization (Q-FISH) analysis, LINC02454 depletion significantly reduced telomerase activity and shortened telomere length. Consistently, pathways related to telomerase, mitosis, and apoptosis were significantly impacted upon LINC02454 knockdown in RNAseq analysis. Functionally, LINC02454-deficient cells exhibited a more significant senescence phenotype in β-galactosidase staining, cell cycle, and apoptosis assays. We further confirmed the role of LINC02454 in HNSCC proliferation through a combination of in vitro and in vivo experiments. The therapeutic potential of targeting LINC02454 was verified by adenovirus-shRNA approach in HNSCC patient-derived xenograft (PDX) models. In summary, our findings provided valuable insights into the molecular mechanisms of HNSCC tumorigenesis and potential targets for future treatment modalities.
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Affiliation(s)
- Biying Chen
- Department of Oncology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201900, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Yue Weng
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Mingyue Li
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zhouliang Bian
- Department of Oncology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201900, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Ye Tao
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wenkai Zhou
- Department of Oral Maxillofacial-Head Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200011, China
| | - Hong Lu
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Shufang He
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Rijing Liao
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jie Huang
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qian Wang
- Department of Oncology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201900, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Ming Xu
- Department of Oncology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201900, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Yunhui Ge
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wei Cao
- Department of Oral Maxillofacial-Head Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200011, China.
| | - Ming Lei
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Yanjie Zhang
- Department of Oncology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 201900, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China.
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5
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Baek M, McHugh R, Anishchenko I, Jiang H, Baker D, DiMaio F. Accurate prediction of protein-nucleic acid complexes using RoseTTAFoldNA. Nat Methods 2024; 21:117-121. [PMID: 37996753 PMCID: PMC10776382 DOI: 10.1038/s41592-023-02086-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 10/16/2023] [Indexed: 11/25/2023]
Abstract
Protein-RNA and protein-DNA complexes play critical roles in biology. Despite considerable recent advances in protein structure prediction, the prediction of the structures of protein-nucleic acid complexes without homology to known complexes is a largely unsolved problem. Here we extend the RoseTTAFold machine learning protein-structure-prediction approach to additionally predict nucleic acid and protein-nucleic acid complexes. We develop a single trained network, RoseTTAFoldNA, that rapidly produces three-dimensional structure models with confidence estimates for protein-DNA and protein-RNA complexes. Here we show that confident predictions have considerably higher accuracy than current state-of-the-art methods. RoseTTAFoldNA should be broadly useful for modeling the structure of naturally occurring protein-nucleic acid complexes, and for designing sequence-specific RNA and DNA-binding proteins.
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Affiliation(s)
- Minkyung Baek
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Ryan McHugh
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Ivan Anishchenko
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Hanlun Jiang
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
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6
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da Silva VL, de Paiva SC, de Oliveira HC, Fernandes CAH, Salvador GHM, Fontes MRDM, Cano MIN. Biochemical and structural characterization of the RT domain of Leishmania sp. telomerase reverse transcriptase. Biochim Biophys Acta Gen Subj 2023; 1867:130451. [PMID: 37751810 DOI: 10.1016/j.bbagen.2023.130451] [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: 12/13/2022] [Revised: 07/22/2023] [Accepted: 08/25/2023] [Indexed: 09/28/2023]
Abstract
BACKGROUND The Leishmania genus comprises parasites that cause leishmaniasis, a neglected disease spread worldwide. Leishmania sp. telomeres are composed of TTAGGG repeats maintained by telomerase. In most eukaryotes, the enzyme minimal complex contains the TER (telomerase RNA) and the TERT (telomerase reverse transcriptase) components. The TERT holds the enzyme catalytic core and is formed by four structural and functional domains (TEN, Telomerase Essential N-terminal; TRBD, Telomerase RNA Binding Domain; RT, the reverse transcriptase domain and CTE, C-Terminal Extension domain). METHODS AND RESULTS Amino acid sequence alignments, protein structure prediction analysis, and protein: nucleic acid interaction assays were used to show that the Leishmania major RT domain preserves the canonical structural elements found in higher eukaryotes, including the canonical motifs and the aspartic acid residues that stabilize the Mg2+ ion cofactor. Furthermore, amino acid substitutions specific to the Leishmania genus and partial conservation of the residues involved with nucleic acid interactions are shown. The purified recombinant Leishmania RT protein is biochemically active and interacts with the G-rich telomeric strand and the TER template sequence. CONCLUSION Our results highlight that the telomerase catalysis mechanism is conserved in a pathogen of medical importance despite the structural peculiarities present in the parasite's RT domain.
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Affiliation(s)
- Vitor Luiz da Silva
- Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Stephany Cacete de Paiva
- Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Hamine Cristina de Oliveira
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Carlos Alexandre H Fernandes
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, IRD, Institut de Minéralogie, Physique des Matériaux et de Cosmochimie, IMPMC, Sorbonne Université, Paris, France
| | | | - Marcos Roberto de M Fontes
- Department of Biophysics and Pharmacology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil; Institute for Advanced Studies of the Sea (IEAMAR), São Paulo State University (UNESP), São Vicente, SP, Brazil
| | - Maria Isabel N Cano
- Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil.
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7
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Udroiu I, Marinaccio J, Sgura A. Many Functions of Telomerase Components: Certainties, Doubts, and Inconsistencies. Int J Mol Sci 2022; 23:ijms232315189. [PMID: 36499514 PMCID: PMC9736166 DOI: 10.3390/ijms232315189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
A growing number of studies have evidenced non-telomeric functions of "telomerase". Almost all of them, however, investigated the non-canonical effects of the catalytic subunit TERT, and not the telomerase ribonucleoprotein holoenzyme. These functions mainly comprise signal transduction, gene regulation and the increase of anti-oxidative systems. Although less studied, TERC (the RNA component of telomerase) has also been shown to be involved in gene regulation, as well as other functions. All this has led to the publication of many reviews on the subject, which, however, are often disseminating personal interpretations of experimental studies of other researchers as original proofs. Indeed, while some functions such as gene regulation seem ascertained, especially because mechanistic findings have been provided, other ones remain dubious and/or are contradicted by other direct or indirect evidence (e.g., telomerase activity at double-strand break site, RNA polymerase activity of TERT, translation of TERC, mitochondrion-processed TERC). In a critical study of the primary evidence so far obtained, we show those functions for which there is consensus, those showing contradictory results and those needing confirmation. The resulting picture, together with some usually neglected aspects, seems to indicate a link between TERT and TERC functions and cellular stemness and gives possible directions for future research.
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8
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Functional Interactions of Kluyveromyces lactis Telomerase Reverse Transcriptase with the Three-Way Junction and the Template Domains of Telomerase RNA. Int J Mol Sci 2022; 23:ijms231810757. [PMID: 36142669 PMCID: PMC9504884 DOI: 10.3390/ijms231810757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/23/2022] Open
Abstract
The ribonucleoprotein telomerase contains two essential components: telomerase RNA (TER) and telomerase reverse transcriptase (TERT, Est2 in yeast). A small portion of TER, termed the template, is copied by TERT onto the chromosome ends, thus compensating for sequence loss due to incomplete DNA replication and nuclease action. Although telomerase RNA is highly divergent in sequence and length across fungi and mammals, structural motifs essential for telomerase function are conserved. Here, we show that Est2 from the budding yeast Kluyveromyces lactis (klEst2) binds specifically to an essential three-way junction (TWJ) structure in K. lactis TER, which shares a conserved structure and sequence features with the essential CR4-CR5 domain of vertebrate telomerase RNA. klEst2 also binds specifically to the template domain, independently and mutually exclusive of its interaction with TWJ. Furthermore, we present the high-resolution structure of the klEst2 telomerase RNA-binding domain (klTRBD). Mutations introduced in vivo in klTRBD based on the solved structure or in TWJ based on its predicted RNA structure caused severe telomere shortening. These results demonstrate the conservation and importance of these domains and the multiple protein–RNA interactions between Est2 and TER for telomerase function.
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9
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Rubtsova M, Dontsova O. How Structural Features Define Biogenesis and Function of Human Telomerase RNA Primary Transcript. Biomedicines 2022; 10:biomedicines10071650. [PMID: 35884955 PMCID: PMC9313293 DOI: 10.3390/biomedicines10071650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/06/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Telomerase RNA has been uncovered as a component of the telomerase enzyme, which acts as a reverse transcriptase and maintains the length of telomeres in proliferated eukaryotic cells. Telomerase RNA is considered to have major functions as a template for telomeric repeat synthesis and as a structural scaffold for telomerase. However, investigations of its biogenesis and turnover, as well as structural data, have provided evidence of functions of telomerase RNA that are not associated with telomerase activity. The primary transcript produced from the human telomerase RNA gene encodes for the hTERP protein, which presents regulatory functions related to autophagy, cellular proliferation, and metabolism. This review focuses on the specific features relating to the biogenesis and structure of human telomerase RNA that support the existence of an isoform suitable for functioning as an mRNA. We believe that further investigation into human telomerase RNA biogenesis mechanisms will provide more levels for manipulating cellular homeostasis, survival, and transformation mechanisms, and may contribute to a deeper understanding of the mechanisms of aging.
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Affiliation(s)
- Maria Rubtsova
- Department of Chemistry, A.N. Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 117997 Moscow, Russia
- Correspondence:
| | - Olga Dontsova
- Department of Chemistry, A.N. Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 117997 Moscow, Russia
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 121205 Moscow, Russia
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10
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Liu B, He Y, Wang Y, Song H, Zhou ZH, Feigon J. Structure of active human telomerase with telomere shelterin protein TPP1. Nature 2022; 604:578-583. [PMID: 35418675 PMCID: PMC9912816 DOI: 10.1038/s41586-022-04582-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/23/2022] [Indexed: 12/13/2022]
Abstract
Human telomerase is a RNA-protein complex that extends the 3' end of linear chromosomes by synthesizing multiple copies of the telomeric repeat TTAGGG1. Its activity is a determinant of cancer progression, stem cell renewal and cellular aging2-5. Telomerase is recruited to telomeres and activated for telomere repeat synthesis by the telomere shelterin protein TPP16,7. Human telomerase has a bilobal structure with a catalytic core ribonuclear protein and a H and ACA box ribonuclear protein8,9. Here we report cryo-electron microscopy structures of human telomerase catalytic core of telomerase reverse transcriptase (TERT) and telomerase RNA (TER (also known as hTR)), and of telomerase with the shelterin protein TPP1. TPP1 forms a structured interface with the TERT-unique telomerase essential N-terminal domain (TEN) and the telomerase RAP motif (TRAP) that are unique to TERT, and conformational dynamics of TEN-TRAP are damped upon TPP1 binding, defining the requirements for recruitment and activation. The structures further reveal that the elements of TERT and TER that are involved in template and telomeric DNA handling-including the TEN domain and the TRAP-thumb helix channel-are largely structurally homologous to those in Tetrahymena telomerase10, and provide unique insights into the mechanism of telomerase activity. The binding site of the telomerase inhibitor BIBR153211,12 overlaps a critical interaction between the TER pseudoknot and the TERT thumb domain. Numerous mutations leading to telomeropathies13,14 are located at the TERT-TER and TEN-TRAP-TPP1 interfaces, highlighting the importance of TER-TERT and TPP1 interactions for telomerase activity, recruitment and as drug targets.
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Affiliation(s)
- Baocheng Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yao He
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, USA
| | - Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - He Song
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
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11
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Davis JA, Chakrabarti K. Telomerase ribonucleoprotein and genome integrity-An emerging connection in protozoan parasites. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 13:e1710. [PMID: 34973045 DOI: 10.1002/wrna.1710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 12/20/2022]
Abstract
Telomerase has an established role in telomere maintenance in eukaryotes. However, recent studies have begun to implicate telomerase in cellular roles beyond telomere maintenance. Specifically, evidence is emerging of cross-talks between telomerase mediated telomere homeostasis and DNA repair pathways. Telomere shortening due to the end replication problem is a constant threat to genome integrity in eukaryotic cells. This poses a particular problem in unicellular parasitic protists because their major virulence genes are located at the subtelomeric loci. Although telomerase is the major regulator of telomere lengthening in eukaryotes, it is less studied in the ancient eukaryotes, including clinically important human pathogens. Recent research is highlighting interplay between telomerase and the DNA damage response in human parasites. The importance of this interplay in pathogen virulence is only beginning to be illuminated, including the potential to highlight novel developmental regulation of telomerase in parasites who transition between multiple developmental stages throughout their life cycle. In this review, we will discuss the telomerase ribonucleoprotein enzyme and DNA repair pathways with emerging views in human parasites to give a broader perspective of the possible connection of telomere, telomerase, and DNA repair pathways across eukaryotic lineages and highlight their potential role in pathogen virulence. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
| | - Kausik Chakrabarti
- University of North Carolina at Charlotte, Charlotte, North Carolina, USA
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12
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Zipper head mechanism of telomere synthesis by human telomerase. Cell Res 2021; 31:1275-1290. [PMID: 34782750 PMCID: PMC8648750 DOI: 10.1038/s41422-021-00586-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/08/2021] [Indexed: 11/08/2022] Open
Abstract
Telomerase, a multi-subunit ribonucleoprotein complex, is a unique reverse transcriptase that catalyzes the processive addition of a repeat sequence to extend the telomere end using a short fragment of its own RNA component as the template. Despite recent structural characterizations of human and Tetrahymena telomerase, it is still a mystery how telomerase repeatedly uses its RNA template to synthesize telomeric DNA. Here, we report the cryo-EM structure of human telomerase holoenzyme bound with telomeric DNA at resolutions of 3.5 Å and 3.9 Å for the catalytic core and biogenesis module, respectively. The structure reveals that a leucine residue Leu980 in telomerase reverse transcriptase (TERT) catalytic subunit functions as a zipper head to limit the length of the short primer-template duplex in the active center. Moreover, our structural and computational analyses suggest that TERT and telomerase RNA (hTR) are organized to harbor a preformed active site that can accommodate short primer-template duplex substrates for catalysis. Furthermore, our findings unveil a double-fingers architecture in TERT that ensures nucleotide addition processivity of human telomerase. We propose that the zipper head Leu980 is a structural determinant for the sequence-based pausing signal of DNA synthesis that coincides with the RNA element-based physical template boundary. Functional analyses unveil that the non-glycine zipper head plays an essential role in both telomerase repeat addition processivity and telomere length homeostasis. In addition, we also demonstrate that this zipper head mechanism is conserved in all eukaryotic telomerases. Together, our study provides an integrated model for telomerase-mediated telomere synthesis.
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Assis LHC, Andrade-Silva D, Shiburah ME, de Oliveira BCD, Paiva SC, Abuchery BE, Ferri YG, Fontes VS, de Oliveira LS, da Silva MS, Cano MIN. Cell Cycle, Telomeres, and Telomerase in Leishmania spp.: What Do We Know So Far? Cells 2021; 10:cells10113195. [PMID: 34831418 PMCID: PMC8621916 DOI: 10.3390/cells10113195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 12/18/2022] Open
Abstract
Leishmaniases belong to the inglorious group of neglected tropical diseases, presenting different degrees of manifestations severity. It is caused by the transmission of more than 20 species of parasites of the Leishmania genus. Nevertheless, the disease remains on the priority list for developing new treatments, since it affects millions in a vast geographical area, especially low-income people. Molecular biology studies are pioneers in parasitic research with the aim of discovering potential targets for drug development. Among them are the telomeres, DNA–protein structures that play an important role in the long term in cell cycle/survival. Telomeres are the physical ends of eukaryotic chromosomes. Due to their multiple interactions with different proteins that confer a likewise complex dynamic, they have emerged as objects of interest in many medical studies, including studies on leishmaniases. This review aims to gather information and elucidate what we know about the phenomena behind Leishmania spp. telomere maintenance and how it impacts the parasite’s cell cycle.
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Affiliation(s)
- Luiz H. C. Assis
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Débora Andrade-Silva
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Mark E. Shiburah
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Beatriz C. D. de Oliveira
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Stephany C. Paiva
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Bryan E. Abuchery
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
| | - Yete G. Ferri
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
| | - Veronica S. Fontes
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Leilane S. de Oliveira
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
| | - Marcelo S. da Silva
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (B.E.A.); (Y.G.F.)
- Correspondence: (M.S.d.S.); (M.I.N.C.)
| | - Maria Isabel N. Cano
- Telomeres Laboratory, Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu 18618-689, Brazil; (L.H.C.A.); (D.A.-S.); (M.E.S.); (B.C.D.d.O.); (S.C.P.); (V.S.F.); (L.S.d.O.)
- Correspondence: (M.S.d.S.); (M.I.N.C.)
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14
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Nguyen THD. Structural biology of human telomerase: progress and prospects. Biochem Soc Trans 2021; 49:1927-1939. [PMID: 34623385 PMCID: PMC8589416 DOI: 10.1042/bst20200042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 12/28/2022]
Abstract
Telomerase ribonucleoprotein was discovered over three decades ago as a specialized reverse transcriptase that adds telomeric repeats to the ends of linear eukaryotic chromosomes. Telomerase plays key roles in maintaining genome stability; and its dysfunction and misregulation have been linked to different types of cancers and a spectrum of human genetic disorders. Over the years, a wealth of genetic and biochemical studies of human telomerase have illuminated its numerous fascinating features. Yet, structural studies of human telomerase have lagged behind due to various challenges. Recent technical developments in cryo-electron microscopy have allowed for the first detailed visualization of the human telomerase holoenzyme, revealing unprecedented insights into its active site and assembly. This review summarizes the cumulative work leading to the recent structural advances, as well as highlights how the future structural work will further advance our understanding of this enzyme.
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Affiliation(s)
- Thi Hoang Duong Nguyen
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, U.K
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15
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Reilly CR, Myllymäki M, Redd R, Padmanaban S, Karunakaran D, Tesmer V, Tsai FD, Gibson CJ, Rana HQ, Zhong L, Saber W, Spellman SR, Hu ZH, Orr EH, Chen MM, De Vivo I, DeAngelo DJ, Cutler C, Antin JH, Neuberg D, Garber JE, Nandakumar J, Agarwal S, Lindsley RC. The clinical and functional effects of TERT variants in myelodysplastic syndrome. Blood 2021; 138:898-911. [PMID: 34019641 PMCID: PMC8432045 DOI: 10.1182/blood.2021011075] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/20/2021] [Indexed: 11/20/2022] Open
Abstract
Germline pathogenic TERT variants are associated with short telomeres and an increased risk of developing myelodysplastic syndrome (MDS) among patients with a telomere biology disorder. We identified TERT rare variants in 41 of 1514 MDS patients (2.7%) without a clinical diagnosis of a telomere biology disorder who underwent allogeneic transplantation. Patients with a TERT rare variant had shorter telomere length (P < .001) and younger age at MDS diagnosis (52 vs 59 years, P = .03) than patients without a TERT rare variant. In multivariable models, TERT rare variants were associated with inferior overall survival (P = .034) driven by an increased incidence of nonrelapse mortality (NRM; P = .015). Death from a noninfectious pulmonary cause was more frequent among patients with a TERT rare variant. Most variants were missense substitutions and classified as variants of unknown significance. Therefore, we cloned all rare missense variants and quantified their impact on telomere elongation in a cell-based assay. We found that 90% of TERT rare variants had severe or intermediate impairment in their capacity to elongate telomeres. Using a homology model of human TERT bound to the shelterin protein TPP1, we inferred that TERT rare variants disrupt domain-specific functions, including catalysis, protein-RNA interactions, and recruitment to telomeres. Our results indicate that the contribution of TERT rare variants to MDS pathogenesis and NRM risk is underrecognized. Routine screening for TERT rare variants in MDS patients regardless of age or clinical suspicion may identify clinically inapparent telomere biology disorders and improve transplant outcomes through risk-adapted approaches.
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Affiliation(s)
| | - Mikko Myllymäki
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | - Robert Redd
- Department of Data Sciences, Dana Farber Cancer Institute, Boston MA
| | - Shilpa Padmanaban
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Druha Karunakaran
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | - Valerie Tesmer
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Frederick D Tsai
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | | | - Huma Q Rana
- Division of Population Sciences, Center for Cancer Genetics and Prevention, and
| | - Liang Zhong
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston MA
- Harvard Stem Cell Institute, Boston MA
| | - Wael Saber
- Center for International Blood andMarrow Transplant Research, Medical College of Wisconsin, Milwaukee, WI
| | - Stephen R Spellman
- Center for International Blood and Marrow Transplant Research, National Marrow Donor Program/Be The Match, Minneapolis, MN
| | - Zhen-Huan Hu
- Center for International Blood andMarrow Transplant Research, Medical College of Wisconsin, Milwaukee, WI
| | - Esther H Orr
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA; and
| | - Maxine M Chen
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA; and
| | - Immaculata De Vivo
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA; and
- Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Daniel J DeAngelo
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | - Corey Cutler
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | - Joseph H Antin
- Division of Hematological Malignancies, Department of Medical Oncology, and
| | - Donna Neuberg
- Department of Data Sciences, Dana Farber Cancer Institute, Boston MA
| | - Judy E Garber
- Division of Population Sciences, Center for Cancer Genetics and Prevention, and
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Suneet Agarwal
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston MA
- Harvard Stem Cell Institute, Boston MA
| | - R Coleman Lindsley
- Division of Hematological Malignancies, Department of Medical Oncology, and
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16
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Logeswaran D, Li Y, Podlevsky JD, Chen JJL. Monophyletic Origin and Divergent Evolution of Animal Telomerase RNA. Mol Biol Evol 2021; 38:215-228. [PMID: 32770221 PMCID: PMC8480181 DOI: 10.1093/molbev/msaa203] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Telomerase RNA (TR) is a noncoding RNA essential for the function of telomerase ribonucleoprotein. TRs from vertebrates, fungi, ciliates, and plants exhibit extreme diversity in size, sequence, secondary structure, and biogenesis pathway. However, the evolutionary pathways leading to such unusual diversity among eukaryotic kingdoms remain elusive. Within the metazoan kingdom, the study of TR has been limited to vertebrates and echinoderms. To understand the origin and evolution of TR across the animal kingdom, we employed a phylogeny-guided, structure-based bioinformatics approach to identify 82 novel TRs from eight previously unexplored metazoan phyla, including the basal-branching sponges. Synthetic TRs from two representative species, a hemichordate and a mollusk, reconstitute active telomerase in vitro with their corresponding telomerase reverse transcriptase components, confirming that they are authentic TRs. Comparative analysis shows that three functional domains, template-pseudoknot (T-PK), CR4/5, and box H/ACA, are conserved between vertebrate and the basal metazoan lineages, indicating a monophyletic origin of the animal TRs with a snoRNA-related biogenesis mechanism. Nonetheless, TRs along separate animal lineages evolved with divergent structural elements in the T-PK and CR4/5 domains. For example, TRs from echinoderms and protostomes lack the canonical CR4/5 and have independently evolved functionally equivalent domains with different secondary structures. In the T-PK domain, a P1.1 stem common in most metazoan clades defines the template boundary, which is replaced by a P1-defined boundary in vertebrates. This study provides unprecedented insight into the divergent evolution of detailed TR secondary structures across broad metazoan lineages, revealing ancestral and later-diversified elements.
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Affiliation(s)
| | - Yang Li
- School of Molecular Sciences, Arizona State University, Tempe, AZ
| | | | - Julian J-L Chen
- School of Molecular Sciences, Arizona State University, Tempe, AZ
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17
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Zhai LT, Rety S, Chen WF, Song ZY, Auguin D, Sun B, Dou SX, Xi XG. Crystal structures of N-terminally truncated telomerase reverse transcriptase from fungi‡. Nucleic Acids Res 2021; 49:4768-4781. [PMID: 33856462 PMCID: PMC8096264 DOI: 10.1093/nar/gkab261] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/28/2021] [Accepted: 04/05/2021] [Indexed: 12/12/2022] Open
Abstract
Telomerase plays critical roles in cellular aging, in the emergence and/or development of cancer, and in the capacity for stem-cell renewal, consists of a catalytic telomerase reverse transcriptase (TERT) and a template-encoding RNA (TER). TERs from diverse organisms contain two conserved structural elements: the template-pseudoknot (T-PK) and a helical three-way junction (TWJ). Species-specific features of the structure and function of telomerase make obtaining a more in-depth understanding of the molecular mechanism of telomerase particularly important. Here, we report the first structural studies of N-terminally truncated TERTs from Candida albicans and Candida tropicalis in apo form and complexed with their respective TWJs in several conformations. We found that Candida TERT proteins perform only one round of telomere addition in the presence or absence of PK/TWJ and display standard reverse transcriptase activity. The C-terminal domain adopts at least two extreme conformations and undergoes conformational interconversion, which regulates the catalytic activity. Most importantly, we identified a conserved tertiary structural motif, called the U-motif, which interacts with the reverse transcriptase domain and is crucial for catalytic activity. Together these results shed new light on the structure and mechanics of fungal TERTs, which show common TERT characteristics, but also display species-specific features.
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Affiliation(s)
- Liu-Tao Zhai
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Stephane Rety
- University Lyon, ENS de Lyon, University Claude Bernard, CNRS UMR 5239, INSERM U1210, LBMC, 46 Allée d’Italie Site Jacques Monod, F-69007 Lyon, France
| | - Wei-Fei Chen
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ze-Yu Song
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Daniel Auguin
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d’Orléans, INRA, USC1328, 45067 Orléans; Structural Motility, Institut Curie, CNRS, UMR 144 Paris, France
| | - Bo Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shuo-Xing Dou
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xu-Guang Xi
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France
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18
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Hu X, Kim JK, Yu C, Jun HI, Liu J, Sankaran B, Huang L, Qiao F. Quality-Control Mechanism for Telomerase RNA Folding in the Cell. Cell Rep 2020; 33:108568. [PMID: 33378677 DOI: 10.1016/j.celrep.2020.108568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 11/12/2020] [Accepted: 12/07/2020] [Indexed: 01/28/2023] Open
Abstract
Long non-coding RNAs can often fold into different conformations. Telomerase RNA, an essential component of the telomerase ribonucleoprotein (RNP) enzyme, must fold into a defined structure to fulfill its function with the protein catalytic subunit (TERT) and other accessory factors. However, the mechanism by which the correct folding of telomerase RNA is warranted in a cell is still unknown. Here we show that La-related protein Pof8 specifically recognizes the conserved pseudoknot region of telomerase RNA and instructs the binding of the Lsm2-8 complex to its mature 3' end, thus selectively protecting the correctly folded RNA from exonucleolytic degradation. In the absence of Pof8, TERT assembles with misfolded RNA and produces little telomerase activity. Therefore, Pof8 plays a key role in telomerase RNA folding quality control, ensuring that TERT only assembles with functional telomerase RNA to form active telomerase. Our finding reveals a mechanism for non-coding RNA folding quality control.
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Affiliation(s)
- Xichan Hu
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Jin-Kwang Kim
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697-4560, USA
| | - Hyun-Ik Jun
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Jinqiang Liu
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA
| | - Lan Huang
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697-4560, USA
| | - Feng Qiao
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA.
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19
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Palka C, Forino NM, Hentschel J, Das R, Stone MD. Folding heterogeneity in the essential human telomerase RNA three-way junction. RNA (NEW YORK, N.Y.) 2020; 26:1787-1800. [PMID: 32817241 PMCID: PMC7668248 DOI: 10.1261/rna.077255.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
Telomeres safeguard the genome by suppressing illicit DNA damage responses at chromosome termini. To compensate for incomplete DNA replication at telomeres, most continually dividing cells, including many cancers, express the telomerase ribonucleoprotein (RNP) complex. Telomerase maintains telomere length by catalyzing de novo synthesis of short DNA repeats using an internal telomerase RNA (TR) template. TRs from diverse species harbor structurally conserved domains that contribute to RNP biogenesis and function. In vertebrate TRs, the conserved regions 4 and 5 (CR4/5) fold into a three-way junction (TWJ) that binds directly to the telomerase catalytic protein subunit and is required for telomerase function. We have analyzed the structural properties of the human TR (hTR) CR4/5 domain using a combination of in vitro chemical mapping, secondary structural modeling, and single-molecule structural analysis. Our data suggest the essential P6.1 stem-loop within CR4/5 is not stably folded in the absence of the telomerase reverse transcriptase in vitro. Rather, the hTR CR4/5 domain adopts a heterogeneous ensemble of conformations. Finally, single-molecule FRET measurements of CR4/5 and a mutant designed to stabilize the P6.1 stem demonstrate that TERT binding selects for a structural conformation of CR4/5 that is not the dominant state of the TERT-free in vitro RNA ensemble.
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Affiliation(s)
- Christina Palka
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
| | - Nicholas M Forino
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064, USA
| | - Jendrik Hentschel
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
| | - Rhiju Das
- Biophysics Program, Stanford University, Stanford, California 94305, USA
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
- Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064, USA
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20
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A structurally conserved human and Tetrahymena telomerase catalytic core. Proc Natl Acad Sci U S A 2020; 117:31078-31087. [PMID: 33229538 DOI: 10.1073/pnas.2011684117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Telomerase is a ribonucleoprotein complex that counteracts the shortening of chromosome ends due to incomplete replication. Telomerase contains a catalytic core of telomerase reverse transcriptase (TERT) and telomerase RNA (TER). However, what defines TERT and separates it from other reverse transcriptases remains a subject of debate. A recent cryoelectron microscopy map of Tetrahymena telomerase revealed the structure of a previously uncharacterized TERT domain (TRAP) with unanticipated interactions with the telomerase essential N-terminal (TEN) domain and roles in telomerase activity. Both TEN and TRAP are absent in the putative Tribolium TERT that has been used as a model for telomerase for over a decade. To investigate the conservation of TRAP and TEN across species, we performed multiple sequence alignments and statistical coupling analysis on all identified TERTs and find that TEN and TRAP have coevolved as telomerase-specific domains. Integrating the data from bioinformatic analysis and the structure of Tetrahymena telomerase, we built a pseudoatomic model of human telomerase catalytic core that accounts for almost all of the cryoelectron microscopy density in a published map, including TRAP in previously unassigned density as well as telomerase RNA domains essential for activity. This more complete model of the human telomerase catalytic core illustrates how domains of TER and TERT, including the TEN-TRAP complex, can interact in a conserved manner to regulate telomere synthesis.
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21
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Schrumpfová PP, Fajkus J. Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes. Biomolecules 2020; 10:biom10101425. [PMID: 33050064 PMCID: PMC7658794 DOI: 10.3390/biom10101425] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- Correspondence:
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65 Brno, Czech Republic
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22
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Zappulla DC. Yeast Telomerase RNA Flexibly Scaffolds Protein Subunits: Results and Repercussions. Molecules 2020; 25:E2750. [PMID: 32545864 PMCID: PMC7356895 DOI: 10.3390/molecules25122750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/25/2022] Open
Abstract
It is said that "hindsight is 20-20", so, given the current year, it is an opportune time to review and learn from experiences studying long noncoding RNAs. Investigation of the Saccharomyces cerevisiae telomerase RNA, TLC1, has unveiled striking flexibility in terms of both structural and functional features. Results support the "flexible scaffold" hypothesis for this 1157-nt telomerase RNA. This model describes TLC1 acting as a tether for holoenzyme protein subunits, and it also may apply to a plethora of RNAs beyond telomerase, such as types of lncRNAs. In this short perspective review, I summarize findings from studying the large yeast telomerase ribonucleoprotein (RNP) complex in the hope that this hindsight will sharpen foresight as so many of us seek to mechanistically understand noncoding RNA molecules from vast transcriptomes.
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Affiliation(s)
- David C Zappulla
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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23
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Human Telomerase RNA: Telomerase Component or More? Biomolecules 2020; 10:biom10060873. [PMID: 32517215 PMCID: PMC7355840 DOI: 10.3390/biom10060873] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 12/16/2022] Open
Abstract
Telomerase is a ribonucleoprotein complex that maintains the lengths of telomeres. Most studies of telomerase function have focused on the involvement of telomerase activation in the immortalization of cancer cells and cellular rejuvenation. However, some studies demonstrated that the results do not meet expectations for telomerase action in telomere maintenance. Recent results give reason to think that major telomerase components-the reverse transcriptase protein subunit and telomerase RNA-may participate in many cellular processes, including the regulation of apoptosis and autophagy, cell survival, pro-proliferative effects, regulation of gene expression, and protection against oxidative stress. However, the difficulties faced by scientist when researching telomerase component functions often reduce confidence in the minor effects observed in experiments. In this review, we focus on the analysis of the functions of telomerase components (paying more attention to the telomerase RNA component), both as a complex and as independent components, providing effects that are not associated with telomerase activity and telomere length maintenance. Despite the fact that the data on alternative roles of telomerase components look illusory, it would be wrong to completely reject the possibility of their involvement in other biological processes excluded from research/discussion. Investigations to improve the understanding of every aspect of the functioning of telomerase components will provide the basis for a more precise development of approaches to regulate cellular homeostasis, which is important for carcinogenesis and aging.
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24
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Brown JA. Unraveling the structure and biological functions of RNA triple helices. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1598. [PMID: 32441456 PMCID: PMC7583470 DOI: 10.1002/wrna.1598] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/06/2020] [Accepted: 04/15/2020] [Indexed: 02/06/2023]
Abstract
It has been nearly 63 years since the first characterization of an RNA triple helix in vitro by Gary Felsenfeld, David Davies, and Alexander Rich. An RNA triple helix consists of three strands: A Watson–Crick RNA double helix whose major‐groove establishes hydrogen bonds with the so‐called “third strand”. In the past 15 years, it has been recognized that these major‐groove RNA triple helices, like single‐stranded and double‐stranded RNA, also mediate prominent biological roles inside cells. Thus far, these triple helices are known to mediate catalysis during telomere synthesis and RNA splicing, bind to ligands and ions so that metabolite‐sensing riboswitches can regulate gene expression, and provide a clever strategy to protect the 3′ end of RNA from degradation. Because RNA triple helices play important roles in biology, there is a renewed interest in better understanding the fundamental properties of RNA triple helices and developing methods for their high‐throughput discovery. This review provides an overview of the fundamental biochemical and structural properties of major‐groove RNA triple helices, summarizes the structure and function of naturally occurring RNA triple helices, and describes prospective strategies to isolate RNA triple helices as a means to establish the “triplexome”. This article is categorized under:RNA Structure and Dynamics > RNA Structure and Dynamics RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems
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Affiliation(s)
- Jessica A Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
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25
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Smith EM, Pendlebury DF, Nandakumar J. Structural biology of telomeres and telomerase. Cell Mol Life Sci 2020; 77:61-79. [PMID: 31728577 PMCID: PMC6986361 DOI: 10.1007/s00018-019-03369-x] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 01/16/2023]
Abstract
Telomeres are protein-DNA complexes that protect chromosome ends from illicit ligation and resection. Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA to counter telomere shortening. Human telomeres are composed of complexes between telomeric DNA and a six-protein complex known as shelterin. The shelterin proteins TRF1 and TRF2 provide the binding affinity and specificity for double-stranded telomeric DNA, while the POT1-TPP1 shelterin subcomplex coats the single-stranded telomeric G-rich overhang that is characteristic of all our chromosome ends. By capping chromosome ends, shelterin protects telomeric DNA from unwanted degradation and end-to-end fusion events. Structures of the human shelterin proteins reveal a network of constitutive and context-specific interactions. The shelterin protein-DNA structures reveal the basis for both the high affinity and DNA sequence specificity of these interactions, and explain how shelterin efficiently protects chromosome ends from genome instability. Several protein-protein interactions, many provided by the shelterin component TIN2, are critical for upholding the end-protection function of shelterin. A survey of these protein-protein interfaces within shelterin reveals a series of "domain-peptide" interactions that allow for efficient binding and adaptability towards new functions. While the modular nature of shelterin has facilitated its part-by-part structural characterization, the interdependence of subunits within telomerase has made its structural solution more challenging. However, the exploitation of several homologs in combination with recent advancements in cryo-EM capabilities has led to an exponential increase in our knowledge of the structural biology underlying telomerase function. Telomerase homologs from a wide range of eukaryotes show a typical retroviral reverse transcriptase-like protein core reinforced with elements that deliver telomerase-specific functions including recruitment to telomeres and high telomere-repeat addition processivity. In addition to providing the template for reverse transcription, the RNA component of telomerase provides a scaffold for the catalytic and accessory protein subunits, defines the limits of the telomeric repeat sequence, and plays a critical role in RNP assembly, stability, and trafficking. While a high-resolution definition of the human telomerase structure is only beginning to emerge, the quick pace of technical progress forecasts imminent breakthroughs in this area. Here, we review the structural biology surrounding telomeres and telomerase to provide a molecular description of mammalian chromosome end protection and end replication.
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Affiliation(s)
- Eric M Smith
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Devon F Pendlebury
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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26
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Rodríguez-Arce E, Cancino P, Arias-Calderón M, Silva-Matus P, Saldías M. Oxoisoaporphines and Aporphines: Versatile Molecules with Anticancer Effects. Molecules 2019; 25:E108. [PMID: 31892146 PMCID: PMC6983244 DOI: 10.3390/molecules25010108] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 02/07/2023] Open
Abstract
Cancer is a disease that involves impaired genome stability with a high mortality index globally. Since its discovery, many have searched for effective treatment, assessing different molecules for their anticancer activity. One of the most studied sources for anticancer therapy is natural compounds and their derivates, like alkaloids, which are organic molecules containing nitrogen atoms in their structure. Among them, oxoisoaporphine and sampangine compounds are receiving increased attention due to their potential anticancer effects. Boldine has also been tested as an anticancer molecule. Boldine is the primary alkaloid extract from boldo, an endemic tree in Chile. These compounds and their derivatives have unique structural properties that potentially have an anticancer mechanism. Different studies showed that this molecule can target cancer cells through several mechanisms, including reactive oxygen species generation, DNA binding, and telomerase enzyme inhibition. In this review, we summarize the state-of-art research related to oxoisoaporphine, sampangine, and boldine, with emphasis on their structural characteristics and the relationship between structure, activity, methods of extraction or synthesis, and anticancer mechanism. With an effective cancer therapy still lacking, these three compounds are good candidates for new anticancer research.
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Affiliation(s)
- Esteban Rodríguez-Arce
- Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago 8370178, Chile;
| | - Patricio Cancino
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380544, Chile;
| | - Manuel Arias-Calderón
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370146, Chile;
| | - Paul Silva-Matus
- Departamento de Ciencias de la Salud, Universidad de Aysén, Coyhaique 5951537, Chile;
| | - Marianela Saldías
- Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago 8370178, Chile;
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27
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Wang Y, Sušac L, Feigon J. Structural Biology of Telomerase. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032383. [PMID: 31451513 DOI: 10.1101/cshperspect.a032383] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Telomerase is a DNA polymerase that extends the 3' ends of chromosomes by processively synthesizing multiple telomeric repeats. It is a unique ribonucleoprotein (RNP) containing a specialized telomerase reverse transcriptase (TERT) and telomerase RNA (TER) with its own template and other elements required with TERT for activity (catalytic core), as well as species-specific TER-binding proteins important for biogenesis and assembly (core RNP); other proteins bind telomerase transiently or constitutively to allow association of telomerase and other proteins with telomere ends for regulation of DNA synthesis. Here we describe how nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography of TER and protein domains helped define the structure and function of the core RNP, laying the groundwork for interpreting negative-stain and cryo electron microscopy (cryo-EM) density maps of Tetrahymena thermophila and human telomerase holoenzymes. As the resolution has improved from ∼30 Å to ∼5 Å, these studies have provided increasingly detailed information on telomerase architecture and mechanism.
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Affiliation(s)
- Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California Los Angeles (UCLA), Los Angeles, California 90095-1569
| | - Lukas Sušac
- Department of Chemistry and Biochemistry, University of California Los Angeles (UCLA), Los Angeles, California 90095-1569
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California Los Angeles (UCLA), Los Angeles, California 90095-1569
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28
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Jansson LI, Stone MD. Single-Molecule Analysis of Reverse Transcriptase Enzymes. Cold Spring Harb Perspect Biol 2019; 11:11/9/a032458. [PMID: 31481455 DOI: 10.1101/cshperspect.a032458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The original discovery of enzymes that synthesize DNA using an RNA template appeared to contradict the central dogma of biology, in which information is transferred, in a unidirectional way, from DNA genes into RNA molecules. The paradigm-shifting discovery of RNA-dependent DNA polymerases, also called reverse transcriptases (RTs), reshaped existing views for how cells function; however, the scope of the impact RTs impose on biology had yet to be realized. In the decades of research since the early 1970s, the biomedical and biotechnological significance of retroviral RTs, as well as the evolutionarily related telomerase enzyme, has become exceedingly clear. One common theme that has emerged in the course of RT-related research is the central role of nucleic acid binding and dynamics during enzyme function. However, directly interrogating these dynamic properties is challenging because of the stochastic properties of biological macromolecules. In this review, we describe how the development of single-molecule biophysical techniques has opened new windows through which to observe the dynamic behavior of this remarkable class of enzymes. Specifically, we focus on how the powerful single-molecule Förster resonance energy transfer (FRET) method has been exploited to study the structure and function of the human immunodeficiency virus (HIV) RT and telomerase ribonucleoprotein (RNP) enzymes. These exciting studies have refined our understanding of RT catalysis, have revealed unforeseen structural rearrangements between RTs and their nucleic acid substrates, and have helped to characterize the mode of action of RT-inhibiting drugs. We conclude with a discussion of how the ongoing development of single-molecule technologies will continue to empower researchers to probe RT mechanisms in new and exciting ways.
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Affiliation(s)
- Linnea I Jansson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064.,The Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064.,The Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064
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29
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Chen X, Tang WJ, Shi JB, Liu MM, Liu XH. Therapeutic strategies for targeting telomerase in cancer. Med Res Rev 2019; 40:532-585. [PMID: 31361345 DOI: 10.1002/med.21626] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
Telomere and telomerase play important roles in abnormal cell proliferation, metastasis, stem cell maintenance, and immortalization in various cancers. Therefore, designing of drugs targeting telomerase and telomere is of great significance. Over the past two decades, considerable knowledge regarding telomere and telomerase has been accumulated, which provides theoretical support for the design of therapeutic strategies such as telomere elongation. Therefore, the development of telomere-based therapies such as nucleoside analogs, non-nucleoside small molecules, antisense technology, ribozymes, and dominant negative human telomerase reverse transcriptase are being prioritized for eradicating a majority of tumors. While the benefits of telomere-based therapies are obvious, there is a need to address the limitations of various therapeutic strategies to improve the possibility of clinical applications. In this study, current knowledge of telomere and telomerase is discussed, and therapeutic strategies based on recent research are reviewed.
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Affiliation(s)
- Xing Chen
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Wen-Jian Tang
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Jing Bo Shi
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Ming Ming Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Xin-Hua Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
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30
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Petrova OA, Mantsyzov AB, Rodina EV, Efimov SV, Hackenberg C, Hakanpää J, Klochkov VV, Lebedev AA, Chugunova AA, Malyavko AN, Zatsepin TS, Mishin AV, Zvereva MI, Lamzin VS, Dontsova OA, Polshakov VI. Structure and function of the N-terminal domain of the yeast telomerase reverse transcriptase. Nucleic Acids Res 2019; 46:1525-1540. [PMID: 29294091 PMCID: PMC5814841 DOI: 10.1093/nar/gkx1275] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/19/2017] [Indexed: 12/19/2022] Open
Abstract
The elongation of single-stranded DNA repeats at the 3′-ends of chromosomes by telomerase is a key process in maintaining genome integrity in eukaryotes. Abnormal activation of telomerase leads to uncontrolled cell division, whereas its down-regulation is attributed to ageing and several pathologies related to early cell death. Telomerase function is based on the dynamic interactions of its catalytic subunit (TERT) with nucleic acids—telomerase RNA, telomeric DNA and the DNA/RNA heteroduplex. Here, we present the crystallographic and NMR structures of the N-terminal (TEN) domain of TERT from the thermotolerant yeast Hansenula polymorpha and demonstrate the structural conservation of the core motif in evolutionarily divergent organisms. We identify the TEN residues that are involved in interactions with the telomerase RNA and in the recognition of the ‘fork’ at the distal end of the DNA product/RNA template heteroduplex. We propose that the TEN domain assists telomerase biological function and is involved in restricting the size of the heteroduplex during telomere repeat synthesis.
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Affiliation(s)
- Olga A Petrova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alexey B Mantsyzov
- Centre for Magnetic Tomography and Spectroscopy, Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena V Rodina
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Sergey V Efimov
- NMR Laboratory, Institute of Physics, Kazan Federal University, 18 Kremlevskaya, Kazan 420008, Russia
| | - Claudia Hackenberg
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Johanna Hakanpää
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Vladimir V Klochkov
- NMR Laboratory, Institute of Physics, Kazan Federal University, 18 Kremlevskaya, Kazan 420008, Russia
| | - Andrej A Lebedev
- Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, UK
| | - Anastasia A Chugunova
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Alexander N Malyavko
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Timofei S Zatsepin
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Alexey V Mishin
- Laboratory for Structural Biology of GPCRs, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Maria I Zvereva
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Victor S Lamzin
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Olga A Dontsova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Vladimir I Polshakov
- Centre for Magnetic Tomography and Spectroscopy, Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
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31
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An Activity Switch in Human Telomerase Based on RNA Conformation and Shaped by TCAB1. Cell 2018; 174:218-230.e13. [PMID: 29804836 DOI: 10.1016/j.cell.2018.04.039] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/22/2018] [Accepted: 04/27/2018] [Indexed: 12/24/2022]
Abstract
Ribonucleoprotein enzymes require dynamic conformations of their RNA constituents for regulated catalysis. Human telomerase employs a non-coding RNA (hTR) with a bipartite arrangement of domains-a template-containing core and a distal three-way junction (CR4/5) that stimulates catalysis through unknown means. Here, we show that telomerase activity unexpectedly depends upon the holoenzyme protein TCAB1, which in turn controls conformation of CR4/5. Cells lacking TCAB1 exhibit a marked reduction in telomerase catalysis without affecting enzyme assembly. Instead, TCAB1 inactivation causes unfolding of CR4/5 helices that are required for catalysis and for association with the telomerase reverse-transcriptase (TERT). CR4/5 mutations derived from patients with telomere biology disorders provoke defects in catalysis and TERT binding similar to TCAB1 inactivation. These findings reveal a conformational "activity switch" in human telomerase RNA controlling catalysis and TERT engagement. The identification of two discrete catalytic states for telomerase suggests an intramolecular means for controlling telomerase in cancers and progenitor cells.
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32
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Jiang J, Wang Y, Sušac L, Chan H, Basu R, Zhou ZH, Feigon J. Structure of Telomerase with Telomeric DNA. Cell 2018; 173:1179-1190.e13. [PMID: 29775593 PMCID: PMC5995583 DOI: 10.1016/j.cell.2018.04.038] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/22/2018] [Accepted: 04/26/2018] [Indexed: 01/05/2023]
Abstract
Telomerase is an RNA-protein complex (RNP) that extends telomeric DNA at the 3' ends of chromosomes using its telomerase reverse transcriptase (TERT) and integral template-containing telomerase RNA (TER). Its activity is a critical determinant of human health, affecting aging, cancer, and stem cell renewal. Lack of atomic models of telomerase, particularly one with DNA bound, has limited our mechanistic understanding of telomeric DNA repeat synthesis. We report the 4.8 Å resolution cryoelectron microscopy structure of active Tetrahymena telomerase bound to telomeric DNA. The catalytic core is an intricately interlocked structure of TERT and TER, including a previously structurally uncharacterized TERT domain that interacts with the TEN domain to physically enclose TER and regulate activity. This complete structure of a telomerase catalytic core and its interactions with telomeric DNA from the template to telomere-interacting p50-TEB complex provides unanticipated insights into telomerase assembly and catalytic cycle and a new paradigm for a reverse transcriptase RNP.
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Affiliation(s)
- Jiansen Jiang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lukas Sušac
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Henry Chan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ritwika Basu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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33
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Nguyen THD, Tam J, Wu RA, Greber BJ, Toso D, Nogales E, Collins K. Cryo-EM structure of substrate-bound human telomerase holoenzyme. Nature 2018; 557:190-195. [PMID: 29695869 PMCID: PMC6223129 DOI: 10.1038/s41586-018-0062-x] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/28/2018] [Indexed: 11/29/2022]
Abstract
Telomerase adds telomeric repeats to chromosome ends to balance incomplete replication. Telomerase regulation is implicated in cancer, aging and other human diseases, but progress towards telomerase clinical manipulation is hampered by the lack of structural data. Here we present the cryo-electron microscopy structure of substrate-bound human telomerase holoenzyme at subnanometer resolution, describing two flexibly RNA-tethered lobes: the catalytic core with telomerase reverse transcriptase (TERT) and conserved motifs of telomerase RNA (hTR), and an H/ACA ribonucleoprotein (RNP). In the catalytic core, RNA encircles TERT, adopting a well-ordered tertiary structure with surprisingly limited protein-RNA interactions. The H/ACA RNP lobe comprises two sets of heterotetrameric H/ACA proteins and one Cajal body protein, TCAB1, representing a pioneering structure of a large eukaryotic family of ribosome and spliceosome biogenesis factors. Our findings provide a structural framework for understanding human telomerase disease mutations and represent an important step towards telomerase-related clinical therapeutics.
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Affiliation(s)
- Thi Hoang Duong Nguyen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.,California Institute for Quantitative Biology, University of California, Berkeley, CA, USA.,Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Miller Institute for Basic Research in Science, University of California, Berkeley, CA, USA
| | - Jane Tam
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Robert A Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.,Harvard Medical School, Boston, MA, USA
| | - Basil J Greber
- California Institute for Quantitative Biology, University of California, Berkeley, CA, USA.,Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Daniel Toso
- California Institute for Quantitative Biology, University of California, Berkeley, CA, USA
| | - Eva Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA. .,California Institute for Quantitative Biology, University of California, Berkeley, CA, USA. .,Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA. .,California Institute for Quantitative Biology, University of California, Berkeley, CA, USA.
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34
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LARP7-like protein Pof8 regulates telomerase assembly and poly(A)+TERRA expression in fission yeast. Nat Commun 2018; 9:586. [PMID: 29422503 PMCID: PMC5805695 DOI: 10.1038/s41467-018-02874-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/05/2018] [Indexed: 02/06/2023] Open
Abstract
Telomerase is a reverse transcriptase complex that ensures stable maintenance of linear eukaryotic chromosome ends by overcoming the end replication problem, posed by the inability of replicative DNA polymerases to fully replicate linear DNA. The catalytic subunit TERT must be assembled properly with its telomerase RNA for telomerase to function, and studies in Tetrahymena have established that p65, a La-related protein 7 (LARP7) family protein, utilizes its C-terminal xRRM domain to promote assembly of the telomerase ribonucleoprotein (RNP) complex. However, LARP7-dependent telomerase complex assembly has been considered as unique to ciliates that utilize RNA polymerase III to transcribe telomerase RNA. Here we show evidence that fission yeast Schizosaccharomyces pombe utilizes the p65-related protein Pof8 and its xRRM domain to promote assembly of RNA polymerase II-encoded telomerase RNA with TERT. Furthermore, we show that Pof8 contributes to repression of the transcription of noncoding RNAs at telomeres. A functional telomerase complex requires that the catalytic TERT subunit be assembled with the template RNA TER1. Here the authors show that Pof8, a possible LARP7 family protein, is required for assembly of the telomerase complex, and repression of lncRNA transcripts at telomeres in S. pombe.
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Current Perspectives of Telomerase Structure and Function in Eukaryotes with Emerging Views on Telomerase in Human Parasites. Int J Mol Sci 2018; 19:ijms19020333. [PMID: 29364142 PMCID: PMC5855555 DOI: 10.3390/ijms19020333] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/10/2018] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
Replicative capacity of a cell is strongly correlated with telomere length regulation. Aberrant lengthening or reduction in the length of telomeres can lead to health anomalies, such as cancer or premature aging. Telomerase is a master regulator for maintaining replicative potential in most eukaryotic cells. It does so by controlling telomere length at chromosome ends. Akin to cancer cells, most single-cell eukaryotic pathogens are highly proliferative and require persistent telomerase activity to maintain constant length of telomere and propagation within their host. Although telomerase is key to unlimited cellular proliferation in both cases, not much was known about the role of telomerase in human parasites (malaria, Trypanosoma, etc.) until recently. Since telomerase regulation is mediated via its own structural components, interactions with catalytic reverse transcriptase and several factors that can recruit and assemble telomerase to telomeres in a cell cycle-dependent manner, we compare and discuss here recent findings in telomerase biology in cancer, aging and parasitic diseases to give a broader perspective of telomerase function in human diseases.
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Wang Y, Feigon J. Structural biology of telomerase and its interaction at telomeres. Curr Opin Struct Biol 2017; 47:77-87. [PMID: 28732250 PMCID: PMC5564310 DOI: 10.1016/j.sbi.2017.06.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 06/29/2017] [Indexed: 12/21/2022]
Abstract
Telomerase is an RNP that synthesizes the 3' ends of linear chromosomes and is an important regulator of telomere length. It contains a single long non-coding telomerase RNA (TER), telomerase reverse transcriptase (TERT), and other proteins that vary among organisms. Recent progress in structural biology of telomerase includes reports of the first cryo-electron microscopy structure of telomerase, from Tetrahymena, new crystal structures of TERT domains, telomerase RNA structures and models, and identification in Tetrahymena telomerase holoenzyme of human homologues of telomere-associated proteins that have provided a more unified view of telomerase interaction at telomeres as well as insights into the role of telomerase RNA in activity and assembly.
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Affiliation(s)
- Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA.
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37
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Mahbub MM, Chowdhury SM, Christensen SM. Globular domain structure and function of restriction-like-endonuclease LINEs: similarities to eukaryotic splicing factor Prp8. Mob DNA 2017; 8:16. [PMID: 29151899 PMCID: PMC5678591 DOI: 10.1186/s13100-017-0097-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/17/2017] [Indexed: 12/16/2022] Open
Abstract
Background R2 elements are a clade of early branching Long Interspersed Elements (LINEs). LINEs are retrotransposable elements whose replication can have profound effects on the genomes in which they reside. No crystal or EM structures exist for the reverse transcriptase (RT) and linker regions of LINEs. Results Using limited proteolysis as a probe for globular domain structure, we show that the protein encoded by the Bombyx mori R2 element has two major globular domains: (1) a small globular domain consisting of the N-terminal zinc finger and Myb motifs, and (2) a large globular domain consisting of the RT, linker, and type II restriction-like endonuclease (RLE). Further digestion of the large globular domain occurred within the RT. Mapping these RT cleavages onto an updated model of the R2Bm RT indicated that the thumb of the RT was largely protected from proteolytic cleavage. The crystal structure of the large globular domain of Prp8, a eukaryotic splicing factor, was a major template used in building the R2Bm RT model, particularly the thumb region. The large fragment of Prp8 consists not only of a RT similar to R2Bm, but also an RLE and a linker connecting the two regions. The linker sequences adjacent to the RLE in LINEs and Prp8 share a set of two important α-helices and a (presumptive) knuckle/ββα structural motif that are closely associated with the thumb. The RLEs of LINEs and Prp8 share a unique catalytic core residue spacing as well as other key residues. Conclusions The protein encoded by RLE LINEs consists of two major globular domains. The larger of the two globular domain contains the RT, linker, and RLE and is similar to the large fragment of the spliceosomal protein Prp8. The similarities are suggestive of possible common ancestry. Electronic supplementary material The online version of this article (10.1186/s13100-017-0097-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- M Murshida Mahbub
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Room 337, Arlington, TX 76010 USA
| | - Saiful M Chowdhury
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 700 Planetarium Place, Room 130, Arlington, TX 76010 USA
| | - Shawn M Christensen
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Room 337, Arlington, TX 76010 USA
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Musgrove C, Jansson LI, Stone MD. New perspectives on telomerase RNA structure and function. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 9. [PMID: 29124890 DOI: 10.1002/wrna.1456] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/08/2017] [Accepted: 09/18/2017] [Indexed: 12/20/2022]
Abstract
Telomerase is an ancient ribonucleoprotein (RNP) that protects the ends of linear chromosomes from the loss of critical coding sequences through repetitive addition of short DNA sequences. These repeats comprise the telomere, which together with many accessory proteins, protect chromosomal ends from degradation and unwanted DNA repair. Telomerase is a unique reverse transcriptase (RT) that carries its own RNA to use as a template for repeat addition. Over decades of research, it has become clear that there are many diverse, crucial functions played by telomerase RNA beyond simply acting as a template. In this review, we highlight recent findings in three model systems: ciliates, yeast and vertebrates, that have shifted the way the field views the structural and mechanistic role(s) of RNA within the functional telomerase RNP complex. Viewed in this light, we hope to demonstrate that while telomerase RNA is just one example of the myriad functional RNA in the cell, insights into its structure and mechanism have wide-ranging impacts. WIREs RNA 2018, 9:e1456. doi: 10.1002/wrna.1456 This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution.
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Affiliation(s)
- Cherie Musgrove
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA
| | - Linnea I Jansson
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.,Center for Molecular Biology of RNA, University of California, Santa Cruz, CA, USA
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Abstract
Telomerase is an RNA-protein complex that extends the 3' ends of linear chromosomes, using a unique telomerase reverse transcriptase (TERT) and template in the telomerase RNA (TR), thereby helping to maintain genome integrity. TR assembles with TERT and species-specific proteins, and telomerase function in vivo requires interaction with telomere-associated proteins. Over the past two decades, structures of domains of TR and TERT as well as other telomerase- and telomere-interacting proteins have provided insights into telomerase function. A recently reported 9-Å cryo-electron microscopy map of the Tetrahymena telomerase holoenzyme has provided a framework for understanding how TR, TERT, and other proteins from ciliate as well as vertebrate telomerase fit and function together as well as unexpected insight into telomerase interaction at telomeres. Here we review progress in understanding the structural basis of human and Tetrahymena telomerase activity, assembly, and interactions.
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Affiliation(s)
- Henry Chan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569; , ,
| | - Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569; , ,
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569; , ,
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40
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Kellermann G, Dingli F, Masson V, Dauzonne D, Ségal-Bendirdjian E, Teulade-Fichou MP, Loew D, Bombard S. Exploring the mechanism of inhibition of human telomerase by cysteine-reactive compounds. FEBS Lett 2017; 591:863-874. [DOI: 10.1002/1873-3468.12589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 01/30/2017] [Accepted: 02/04/2017] [Indexed: 11/05/2022]
Affiliation(s)
| | - Florent Dingli
- Laboratoire de Spectrometrie de Masse Protéomique; Institut Curie; University PSL; Paris France
| | - Vanessa Masson
- Laboratoire de Spectrometrie de Masse Protéomique; Institut Curie; University PSL; Paris France
| | - Daniel Dauzonne
- Département Recherche; CNRS UMR3666/INSERM U1143; Institut Curie; Paris Cedex 05 France
| | | | | | - Damarys Loew
- Laboratoire de Spectrometrie de Masse Protéomique; Institut Curie; University PSL; Paris France
| | - Sophie Bombard
- INSERM UMR-S 1007; Université Paris Descartes; France
- CNRS UMR9187/INSERM U1196; Institut Curie; Centre Universitaire; University Paris Sud; Orsay France
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41
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Hoffman H, Rice C, Skordalakes E. Structural Analysis Reveals the Deleterious Effects of Telomerase Mutations in Bone Marrow Failure Syndromes. J Biol Chem 2017; 292:4593-4601. [PMID: 28154186 DOI: 10.1074/jbc.m116.771204] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/27/2017] [Indexed: 12/17/2022] Open
Abstract
Naturally occurring mutations in the ribonucleoprotein reverse transcriptase, telomerase, are associated with the bone marrow failure syndromes dyskeratosis congenita, aplastic anemia, and idiopathic pulmonary fibrosis. However, the mechanism by which these mutations impact telomerase function remains unknown. Here we present the structure of the human telomerase C-terminal extension (or thumb domain) determined by the method of single-wavelength anomalous diffraction to 2.31 Å resolution. We also used direct telomerase activity and nucleic acid binding assays to explain how naturally occurring mutations within this portion of telomerase contribute to human disease. The single mutations localize within three highly conserved regions of the telomerase thumb domain referred to as motifs E-I (thumb loop and helix), E-II, and E-III (the FVYL pocket, comprising the hydrophobic residues Phe-1012, Val-1025, Tyr-1089, and Leu-1092). Biochemical data show that the mutations associated with dyskeratosis congenita, aplastic anemia, and idiopathic pulmonary fibrosis disrupt the binding between the protein subunit reverse transcriptase of the telomerase and its nucleic acid substrates leading to loss of telomerase activity and processivity. Collectively our data show that although these mutations do not alter the overall stability or expression of telomerase reverse transcriptase, these rare genetic disorders are associated with an impaired telomerase holoenzyme that is unable to correctly assemble with its nucleic acid substrates, leading to incomplete telomere extension and telomere attrition, which are hallmarks of these diseases.
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Affiliation(s)
- Hunter Hoffman
- From the Department of Gene Expression and Regulation, Wistar Institute, Philadelphia, Pennsylvania 19104 and
| | - Cory Rice
- From the Department of Gene Expression and Regulation, Wistar Institute, Philadelphia, Pennsylvania 19104 and.,the Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Emmanuel Skordalakes
- From the Department of Gene Expression and Regulation, Wistar Institute, Philadelphia, Pennsylvania 19104 and .,the Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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42
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Parks JW, Kappel K, Das R, Stone MD. Single-molecule FRET-Rosetta reveals RNA structural rearrangements during human telomerase catalysis. RNA (NEW YORK, N.Y.) 2017; 23:175-188. [PMID: 28096444 PMCID: PMC5238793 DOI: 10.1261/rna.058743.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 09/23/2016] [Indexed: 06/06/2023]
Abstract
Maintenance of telomeres by telomerase permits continuous proliferation of rapidly dividing cells, including the majority of human cancers. Despite its direct biomedical significance, the architecture of the human telomerase complex remains unknown. Generating homogeneous telomerase samples has presented a significant barrier to developing improved structural models. Here we pair single-molecule Förster resonance energy transfer (smFRET) measurements with Rosetta modeling to map the conformations of the essential telomerase RNA core domain within the active ribonucleoprotein. FRET-guided modeling places the essential pseudoknot fold distal to the active site on a protein surface comprising the C-terminal element, a domain that shares structural homology with canonical polymerase thumb domains. An independently solved medium-resolution structure of Tetrahymena telomerase provides a blind test of our modeling methodology and sheds light on the structural homology of this domain across diverse organisms. Our smFRET-Rosetta models reveal nanometer-scale rearrangements within the RNA core domain during catalysis. Taken together, our FRET data and pseudoatomic molecular models permit us to propose a possible mechanism for how RNA core domain rearrangement is coupled to template hybrid elongation.
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Affiliation(s)
- Joseph W Parks
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
- Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064, USA
| | - Kalli Kappel
- Biophysics Program, Stanford University, Stanford, California 94305, USA
| | - Rhiju Das
- Biophysics Program, Stanford University, Stanford, California 94305, USA
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
- Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064, USA
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43
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Abstract
Telomerase is the essential reverse transcriptase required for linear chromosome maintenance in most eukaryotes. Telomerase supplements the tandem array of simple-sequence repeats at chromosome ends to compensate for the DNA erosion inherent in genome replication. The template for telomerase reverse transcriptase is within the RNA subunit of the ribonucleoprotein complex, which in cells contains additional telomerase holoenzyme proteins that assemble the active ribonucleoprotein and promote its function at telomeres. Telomerase is distinct among polymerases in its reiterative reuse of an internal template. The template is precisely defined, processively copied, and regenerated by release of single-stranded product DNA. New specificities of nucleic acid handling that underlie the catalytic cycle of repeat synthesis derive from both active site specialization and new motif elaborations in protein and RNA subunits. Studies of telomerase provide unique insights into cellular requirements for genome stability, tissue renewal, and tumorigenesis as well as new perspectives on dynamic ribonucleoprotein machines.
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Affiliation(s)
- R Alex Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202; , , ,
| | - Heather E Upton
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202; , , ,
| | - Jacob M Vogan
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202; , , ,
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202; , , ,
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44
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Martin WJ, Reiter NJ. Structural Roles of Noncoding RNAs in the Heart of Enzymatic Complexes. Biochemistry 2016; 56:3-13. [PMID: 27935277 DOI: 10.1021/acs.biochem.6b01106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Over billions of years of evolution, nature has embraced proteins as the major workhorse molecules of the cell. However, nearly every aspect of metabolism is dependent upon how structured RNAs interact with proteins, ligands, and other nucleic acids. Key processes, including telomere maintenance, RNA processing, and protein synthesis, require large RNAs that assemble into elaborate three-dimensional shapes. These RNAs can (i) act as flexible scaffolds for protein subunits, (ii) participate directly in substrate recognition, and (iii) serve as catalytic components. Here, we juxtapose the near atomic level interactions of three ribonucleoprotein complexes: ribonuclease P (involved in 5' pre-tRNA processing), the spliceosome (responsible for pre-mRNA splicing), and telomerase (an RNA-directed DNA polymerase that extends the ends of chromosomes). The focus of this perspective is profiling the structural and dynamic roles of RNAs at the core of these enzymes, highlighting how large RNAs contribute to molecular recognition and catalysis.
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Affiliation(s)
- William J Martin
- Department of Biochemistry, Vanderbilt University , Nashville, Tennessee 37232, United States
| | - Nicholas J Reiter
- Department of Biochemistry, Vanderbilt University , Nashville, Tennessee 37232, United States
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45
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Cash DD, Feigon J. Structure and folding of the Tetrahymena telomerase RNA pseudoknot. Nucleic Acids Res 2016; 45:482-495. [PMID: 27899638 PMCID: PMC5224487 DOI: 10.1093/nar/gkw1153] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/26/2016] [Accepted: 11/03/2016] [Indexed: 12/21/2022] Open
Abstract
Telomerase maintains telomere length at the ends of linear chromosomes using an integral telomerase RNA (TER) and telomerase reverse transcriptase (TERT). An essential part of TER is the template/pseudoknot domain (t/PK) which includes the template, for adding telomeric repeats, template boundary element (TBE), and pseudoknot, enclosed in a circle by stem 1. The Tetrahymena telomerase holoenzyme catalytic core (p65-TER-TERT) was recently modeled in our 9 Å resolution cryo-electron microscopy map by fitting protein and TER domains, including a solution NMR structure of the Tetrahymena pseudoknot. Here, we describe in detail the structure and folding of the isolated pseudoknot, which forms a compact structure with major groove U•A-U and novel C•G-A+ base triples. Base substitutions that disrupt the base triples reduce telomerase activity in vitro. NMR studies also reveal that the pseudoknot does not form in the context of full-length TER in the absence of TERT, due to formation of a competing structure that sequesters pseudoknot residues. The residues around the TBE remain unpaired, potentially providing access by TERT to this high affinity binding site during an early step in TERT-TER assembly. A model for the assembly pathway of the catalytic core is proposed.
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Affiliation(s)
- Darian D Cash
- Department of Chemistry and Biochemistry, and Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, and Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
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46
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Boyraz B, Bellomo CM, Fleming MD, Cutler CS, Agarwal S. A novel TERC CR4/CR5 domain mutation causes telomere disease via decreased TERT binding. Blood 2016; 128:2089-2092. [PMID: 27587879 PMCID: PMC5073186 DOI: 10.1182/blood-2016-04-710160] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Baris Boyraz
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Harvard Stem Cell Institute, Boston, MA
- Department of Pediatrics, Harvard Medical School, Boston, MA
- Department of Basic Oncology, Hacettepe University Cancer Institute, Ankara, Turkey
| | | | - Mark D Fleming
- Department of Pathology, Boston Children's Hospital, Boston, MA; and
| | - Corey S Cutler
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Suneet Agarwal
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Harvard Stem Cell Institute, Boston, MA
- Department of Pediatrics, Harvard Medical School, Boston, MA
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47
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Structural conservation in the template/pseudoknot domain of vertebrate telomerase RNA from teleost fish to human. Proc Natl Acad Sci U S A 2016; 113:E5125-34. [PMID: 27531956 DOI: 10.1073/pnas.1607411113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Telomerase is an RNA-protein complex that includes a unique reverse transcriptase that catalyzes the addition of single-stranded telomere DNA repeats onto the 3' ends of linear chromosomes using an integral telomerase RNA (TR) template. Vertebrate TR contains the template/pseudoknot (t/PK) and CR4/5 domains required for telomerase activity in vitro. All vertebrate pseudoknots include two subdomains: P2ab (helices P2a and P2b with a 5/6-nt internal loop) and the minimal pseudoknot (P2b-P3 and associated loops). A helical extension of P2a, P2a.1, is specific to mammalian TR. Using NMR, we investigated the structures of the full-length TR pseudoknot and isolated subdomains in Oryzias latipes (Japanese medaka fish), which has the smallest vertebrate TR identified to date. We determined the solution NMR structure and studied the dynamics of medaka P2ab, and identified all base pairs and tertiary interactions in the minimal pseudoknot. Despite differences in length and sequence, the structure of medaka P2ab is more similar to human P2ab than predicted, and the medaka minimal pseudoknot has the same tertiary interactions as the human pseudoknot. Significantly, although P2a.1 is not predicted to form in teleost fish, we find that it forms in the full-length pseudoknot via an unexpected hairpin. Model structures of the subdomains are combined to generate a model of t/PK. These results provide evidence that the architecture for the vertebrate t/PK is conserved from teleost fish to human. The organization of the t/PK on telomerase reverse transcriptase for medaka and human is modeled based on the cryoEM structure of Tetrahymena telomerase, providing insight into function.
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48
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Podlevsky JD, Li Y, Chen JJL. The functional requirement of two structural domains within telomerase RNA emerged early in eukaryotes. Nucleic Acids Res 2016; 44:9891-9901. [PMID: 27378779 PMCID: PMC5175330 DOI: 10.1093/nar/gkw605] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 11/30/2022] Open
Abstract
Telomerase emerged during evolution as a prominent solution to the eukaryotic linear chromosome end-replication problem. Telomerase minimally comprises the catalytic telomerase reverse transcriptase (TERT) and telomerase RNA (TR) that provides the template for telomeric DNA synthesis. While the TERT protein is well-conserved across taxa, TR is highly divergent amongst distinct groups of species. Herein, we have identified the essential functional domains of TR from the basal eukaryotic species Trypanosoma brucei, revealing the ancestry of TR comprising two distinct structural core domains that can assemble in trans with TERT and reconstitute active telomerase enzyme in vitro. The upstream essential domain of T. brucei TR, termed the template core, constitutes three short helices in addition to the 11-nt template. Interestingly, the trypanosome template core domain lacks the ubiquitous pseudoknot found in all known TRs, suggesting later evolution of this critical structural element. The template-distal domain is a short stem-loop, termed equivalent CR4/5 (eCR4/5). While functionally similar to vertebrate and fungal CR4/5, trypanosome eCR4/5 is structurally distinctive, lacking the essential P6.1 stem-loop. Our functional study of trypanosome TR core domains suggests that the functional requirement of two discrete structural domains is a common feature of TRs and emerged early in telomerase evolution.
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Affiliation(s)
- Joshua D Podlevsky
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Yang Li
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Julian J-L Chen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
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49
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Chen Y, Zhang Y. Functional and mechanistic analysis of telomerase: An antitumor drug target. Pharmacol Ther 2016; 163:24-47. [DOI: 10.1016/j.pharmthera.2016.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/29/2016] [Indexed: 01/26/2023]
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50
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Abstract
Telomerase is the eukaryotic solution to the ‘end-replication problem’ of linear chromosomes by synthesising the highly repetitive DNA constituent of telomeres, the nucleoprotein cap that protects chromosome termini. Functioning as a ribonucleoprotein (RNP) enzyme, telomerase is minimally composed of the highly conserved catalytic telomerase reverse transcriptase (TERT) and essential telomerase RNA (TR) component. Beyond merely providing the template for telomeric DNA synthesis, TR is an innate telomerase component and directly facilitates enzymatic function. TR accomplishes this by having evolved structural elements for stable assembly with the TERT protein and the regulation of the telomerase catalytic cycle. Despite its prominence and prevalence, TR has profoundly diverged in length, sequence, and biogenesis pathway among distinct evolutionary lineages. This diversity has generated numerous structural and mechanistic solutions for ensuring proper RNP formation and high fidelity telomeric DNA synthesis. Telomerase provides unique insights into RNA and protein coevolution within RNP enzymes.
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Affiliation(s)
- Joshua D Podlevsky
- a School of Molecular Sciences, Arizona State University , Tempe , AZ , USA
| | - Julian J-L Chen
- a School of Molecular Sciences, Arizona State University , Tempe , AZ , USA
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