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Červenák F, Sepšiová R, Peška V, Nosek J, Tomáška Ľ. Primary Scientific Literature Represents an Essential Source of Telomeric Repeat Sequences. Microbiol Spectr 2023; 11:e0123023. [PMID: 37310973 PMCID: PMC10433822 DOI: 10.1128/spectrum.01230-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023] Open
Affiliation(s)
- Filip Červenák
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Regina Sepšiová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Vratislav Peška
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Ľubomír Tomáška
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
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2
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Lue NF, Autexier C. Orchestrating nucleic acid-protein interactions at chromosome ends: telomerase mechanisms come into focus. Nat Struct Mol Biol 2023; 30:878-890. [PMID: 37400652 PMCID: PMC10539978 DOI: 10.1038/s41594-023-01022-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/16/2023] [Indexed: 07/05/2023]
Abstract
Telomerase is a special reverse transcriptase ribonucleoprotein dedicated to the synthesis of telomere repeats that protect chromosome ends. Among reverse transcriptases, telomerase is unique in using a stably associated RNA with an embedded template to synthesize a specified sequence. Moreover, it is capable of iteratively copying the same template region (repeat addition processivity) through multiple rounds of RNA-DNA unpairing and reannealing, that is, the translocation reaction. Biochemical analyses of telomerase over the past 3 decades in protozoa, fungi and mammals have identified structural elements that underpin telomerase mechanisms and have led to models that account for the special attributes of telomerase. Notably, these findings and models can now be interpreted and adjudicated through recent cryo-EM structures of Tetrahymena and human telomerase holoenzyme complexes in association with substrates and regulatory proteins. Collectively, these structures reveal the intricate protein-nucleic acid interactions that potentiate telomerase's unique translocation reaction and clarify how this enzyme reconfigures the basic reverse transcriptase scaffold to craft a polymerase dedicated to the synthesis of telomere DNA. Among the many new insights is the resolution of the telomerase 'anchor site' proposed more than 3 decades ago. The structures also highlight the nearly universal conservation of a protein-protein interface between an oligonucleotide/oligosaccharide-binding (OB)-fold regulatory protein and the telomerase catalytic subunit, which enables spatial and temporal regulation of telomerase function in vivo. In this Review, we discuss key features of the structures in combination with relevant functional analyses. We also examine conserved and divergent aspects of telomerase mechanisms as gleaned from studies in different model organisms.
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Affiliation(s)
- Neal F Lue
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA.
| | - Chantal Autexier
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Anatomy and Cell Biology and Department of Medicine, McGill University, Montreal, Quebec, Canada.
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3
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Sanpedro-Luna JA, Jacinto-Vázquez JJ, Anastacio-Marcelino E, Posadas-Gutiérrez CM, Olmos-Pineda I, González-Bernal JA, Carcaño-Montiel M, Vega-Alvarado L, Vázquez-Cruz C, Sánchez-Alonso P. Telomerase RNA plays a major role in the completion of the life cycle in Ustilago maydis and shares conserved domains with other Ustilaginales. PLoS One 2023; 18:e0281251. [PMID: 36952474 PMCID: PMC10035886 DOI: 10.1371/journal.pone.0281251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 03/25/2023] Open
Abstract
The RNA subunit of telomerase is an essential component whose primary sequence and length are poorly conserved among eukaryotic organisms. The phytopathogen Ustilago maydis is a dimorphic fungus of the order Ustilaginales. We analyzed several species of Ustilaginales to computationally identify the TElomere RNA (TER) gene ter1. To confirm the identity of the TER gene, we disrupted the gene and characterized telomerase-negative mutants. Similar to catalytic TERT mutants, ter1Δ mutants exhibit phenotypes of growth delay, telomere shortening and low replicative potential. ter1-disrupted mutants were unable to infect maize seedlings in heterozygous crosses and showed defects such as cell cycle arrest and segregation failure. We concluded that ter1, which encodes the TER subunit of the telomerase of U. maydis, have similar and perhaps more extensive functions than trt1.
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Affiliation(s)
- Juan Antonio Sanpedro-Luna
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - José Juan Jacinto-Vázquez
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Estela Anastacio-Marcelino
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | | | - Iván Olmos-Pineda
- Facultad de Ciencias de la Computación, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Jesús Antonio González-Bernal
- Department of Computer Science and Engineering, The University of Texas Arlington, Arlington, Texas, United States of America
| | - Moisés Carcaño-Montiel
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Leticia Vega-Alvarado
- Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México, México
| | - Candelario Vázquez-Cruz
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Patricia Sánchez-Alonso
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
- * E-mail:
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4
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Post-Transcriptional and Post-Translational Modifications in Telomerase Biogenesis and Recruitment to Telomeres. Int J Mol Sci 2023; 24:ijms24055027. [PMID: 36902458 PMCID: PMC10003056 DOI: 10.3390/ijms24055027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Telomere length is associated with the proliferative potential of cells. Telomerase is an enzyme that elongates telomeres throughout the entire lifespan of an organism in stem cells, germ cells, and cells of constantly renewed tissues. It is activated during cellular division, including regeneration and immune responses. The biogenesis of telomerase components and their assembly and functional localization to the telomere is a complex system regulated at multiple levels, where each step must be tuned to the cellular requirements. Any defect in the function or localization of the components of the telomerase biogenesis and functional system will affect the maintenance of telomere length, which is critical to the processes of regeneration, immune response, embryonic development, and cancer progression. An understanding of the regulatory mechanisms of telomerase biogenesis and activity is necessary for the development of approaches toward manipulating telomerase to influence these processes. The present review focuses on the molecular mechanisms involved in the major steps of telomerase regulation and the role of post-transcriptional and post-translational modifications in telomerase biogenesis and function in yeast and vertebrates.
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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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6
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Gray M, Chester S, Jabbari H. KnotAli: informed energy minimization through the use of evolutionary information. BMC Bioinformatics 2022; 23:159. [PMID: 35505276 PMCID: PMC9063079 DOI: 10.1186/s12859-022-04673-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 04/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Improving the prediction of structures, especially those containing pseudoknots (structures with crossing base pairs) is an ongoing challenge. Homology-based methods utilize structural similarities within a family to predict the structure. However, their prediction is limited to the consensus structure, and by the quality of the alignment. Minimum free energy (MFE) based methods, on the other hand, do not rely on familial information and can predict structures of novel RNA molecules. Their prediction normally suffers from inaccuracies due to their underlying energy parameters. RESULTS We present a new method for prediction of RNA pseudoknotted secondary structures that combines the strengths of MFE prediction and alignment-based methods. KnotAli takes a multiple RNA sequence alignment as input and uses covariation and thermodynamic energy minimization to predict possibly pseudoknotted secondary structures for each individual sequence in the alignment. We compared KnotAli's performance to that of three other alignment-based programs, two that can handle pseudoknotted structures and one control, on a large data set of 3034 RNA sequences with varying lengths and levels of sequence conservation from 10 families with pseudoknotted and pseudoknot-free reference structures. We produced sequence alignments for each family using two well-known sequence aligners (MUSCLE and MAFFT). CONCLUSIONS We found KnotAli's performance to be superior in 6 of the 10 families for MUSCLE and 7 of the 10 for MAFFT. While both KnotAli and Cacofold use background noise correction strategies, we found KnotAli's predictions to be less dependent on the alignment quality. KnotAli can be found online at the Zenodo image: https://doi.org/10.5281/zenodo.5794719.
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Affiliation(s)
- Mateo Gray
- Department of Computer Science, University of Victoria, Victoria, Canada
| | - Sean Chester
- Department of Computer Science, University of Victoria, Victoria, Canada
| | - Hosna Jabbari
- Department of Computer Science, University of Victoria, Victoria, Canada. .,Institute on Aging and Lifelong Health, University of Victoria, Victoria, Canada.
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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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8
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Telomeric-Like Repeats Flanked by Sequences Retrotranscribed from the Telomerase RNA Inserted at DNA Double-Strand Break Sites during Vertebrate Genome Evolution. Int J Mol Sci 2021; 22:ijms222011048. [PMID: 34681704 PMCID: PMC8537989 DOI: 10.3390/ijms222011048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 01/28/2023] Open
Abstract
Interstitial telomeric sequences (ITSs) are stretches of telomeric-like repeats located at internal chromosomal sites. We previously demonstrated that ITSs have been inserted during the repair of DNA double-strand breaks in the course of evolution and that some rodent ITSs, called TERC-ITSs, are flanked by fragments retrotranscribed from the telomerase RNA component (TERC). In this work, we carried out an extensive search of TERC-ITSs in 30 vertebrate genomes and identified 41 such loci in 22 species, including in humans and other primates. The fragment retrotranscribed from the TERC RNA varies in different lineages and its sequence seems to be related to the organization of TERC. Through comparative analysis of TERC-ITSs with orthologous empty loci, we demonstrated that, at each locus, the TERC-like sequence and the ITS have been inserted in one step in the course of evolution. Our findings suggest that telomerase participated in a peculiar pathway of DNA double-strand break repair involving retrotranscription of its RNA component and that this mechanism may be active in all vertebrate species. These results add new evidence to the hypothesis that RNA-templated DNA repair mechanisms are active in vertebrate cells.
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9
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Fajkus P, Kilar A, Nelson ADL, Holá M, Peška V, Goffová I, Fojtová M, Zachová D, Fulnečková J, Fajkus J. Evolution of plant telomerase RNAs: farther to the past, deeper to the roots. Nucleic Acids Res 2021; 49:7680-7694. [PMID: 34181710 PMCID: PMC8287931 DOI: 10.1093/nar/gkab545] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 01/10/2023] Open
Abstract
The enormous sequence heterogeneity of telomerase RNA (TR) subunits has thus far complicated their characterization in a wider phylogenetic range. Our recent finding that land plant TRs are, similarly to known ciliate TRs, transcribed by RNA polymerase III and under the control of the type-3 promoter, allowed us to design a novel strategy to characterize TRs in early diverging Viridiplantae taxa, as well as in ciliates and other Diaphoretickes lineages. Starting with the characterization of the upstream sequence element of the type 3 promoter that is conserved in a number of small nuclear RNAs, and the expected minimum TR template region as search features, we identified candidate TRs in selected Diaphoretickes genomes. Homologous TRs were then used to build covariance models to identify TRs in more distant species. Transcripts of the identified TRs were confirmed by transcriptomic data, RT-PCR and Northern hybridization. A templating role for one of our candidates was validated in Physcomitrium patens. Analysis of secondary structure demonstrated a deep conservation of motifs (pseudoknot and template boundary element) observed in all published TRs. These results elucidate the evolution of the earliest eukaryotic TRs, linking the common origin of TRs across Diaphoretickes, and underlying evolutionary transitions in telomere repeats.
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Affiliation(s)
- Petr Fajkus
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno CZ-61265, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic
| | - Agata Kilar
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | | | - Marcela Holá
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague CZ-16000, Czech Republic
| | - Vratislav Peška
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno CZ-61265, Czech Republic
| | - Ivana Goffová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Dagmar Zachová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic
| | - Jana Fulnečková
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno CZ-61265, Czech Republic
| | - Jiří Fajkus
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno CZ-61265, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno CZ-62500, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
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10
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Diotti R, Esposito M, Shen CH. Telomeric and Sub-Telomeric Structure and Implications in Fungal Opportunistic Pathogens. Microorganisms 2021; 9:microorganisms9071405. [PMID: 34209786 PMCID: PMC8305976 DOI: 10.3390/microorganisms9071405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/11/2021] [Accepted: 06/25/2021] [Indexed: 12/28/2022] Open
Abstract
Telomeres are long non-coding regions found at the ends of eukaryotic linear chromosomes. Although they have traditionally been associated with the protection of linear DNA ends to avoid gene losses during each round of DNA replication, recent studies have demonstrated that the role of these sequences and their adjacent regions go beyond just protecting chromosomal ends. Regions nearby to telomeric sequences have now been identified as having increased variability in the form of duplications and rearrangements that result in new functional abilities and biodiversity. Furthermore, unique fungal telomeric and chromatin structures have now extended clinical capabilities and understanding of pathogenicity levels. In this review, telomere structure, as well as functional implications, will be examined in opportunistic fungal pathogens, including Aspergillus fumigatus, Candida albicans, Candida glabrata, and Pneumocystis jirovecii.
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Affiliation(s)
- Raffaella Diotti
- Department of Biological Sciences, Bronx Community College, City University of New York, New York, NY 10453, USA;
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
| | - Michelle Esposito
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
- Department of Biology, College of Staten Island, City University of New York, New York, NY 10314, USA
| | - Chang Hui Shen
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
- Department of Biology, College of Staten Island, City University of New York, New York, NY 10314, USA
- The Graduate Center, PhD Program in Biochemistry, City University of New York, New York, NY 10016, USA
- Institute for Macromolecular Assemblies, City University of New York, New York, NY 10031, USA
- Correspondence: ; Tel.: +1-(718)-982-3998; Fax: +1-(718)-982-3852
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11
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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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12
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Peska V, Fajkus P, Bubeník M, Brázda V, Bohálová N, Dvořáček V, Fajkus J, Garcia S. Extraordinary diversity of telomeres, telomerase RNAs and their template regions in Saccharomycetaceae. Sci Rep 2021; 11:12784. [PMID: 34140564 PMCID: PMC8211666 DOI: 10.1038/s41598-021-92126-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 06/03/2021] [Indexed: 01/08/2023] Open
Abstract
Telomerase RNA (TR) carries the template for synthesis of telomere DNA and provides a scaffold for telomerase assembly. Fungal TRs are long and have been compared to higher eukaryotes, where they show considerable diversity within phylogenetically close groups. TRs of several Saccharomycetaceae were recently identified, however, many of these remained uncharacterised in the template region. Here we show that this is mainly due to high variability in telomere sequence. We predicted the telomere sequences using Tandem Repeats Finder and then we identified corresponding putative template regions in TR candidates. Remarkably long telomere units and the corresponding putative TRs were found in Tetrapisispora species. Notably, variable lengths of the annealing sequence of the template region (1–10 nt) were found. Consequently, species with the same telomere sequence may not harbour identical TR templates. Thus, TR sequence alone can be used to predict a template region and telomere sequence, but not to determine these exactly. A conserved feature of telomere sequences, tracts of adjacent Gs, led us to test the propensity of individual telomere sequences to form G4. The results show highly diverse values of G4-propensity, indicating the lack of ubiquitous conservation of this feature across Saccharomycetaceae.
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Affiliation(s)
- Vratislav Peska
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic.
| | - Petr Fajkus
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno, 62500, Czech Republic
| | - Michal Bubeník
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno, 62500, Czech Republic
| | - Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic
| | - Natália Bohálová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic.,Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 62500, Czech Republic
| | - Vojtěch Dvořáček
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic
| | - Jiří Fajkus
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, 61265, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno, 62500, Czech Republic
| | - Sònia Garcia
- Institut Botànic de Barcelona (IBB-CSIC, Ajuntament de Barcelona), Passeig del Migdia s/n, 08038, Barcelona, Catalonia, Spain.
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13
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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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14
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Červenák F, Sepšiová R, Nosek J, Tomáška Ľ. Step-by-Step Evolution of Telomeres: Lessons from Yeasts. Genome Biol Evol 2020; 13:6127219. [PMID: 33537752 PMCID: PMC7857110 DOI: 10.1093/gbe/evaa268] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 12/23/2022] Open
Abstract
In virtually every eukaryotic species, the ends of nuclear chromosomes are protected by telomeres, nucleoprotein structures counteracting the end-replication problem and suppressing recombination and undue DNA repair. Although in most cases, the primary structure of telomeric DNA is conserved, there are several exceptions to this rule. One is represented by the telomeric repeats of ascomycetous yeasts, which encompass a great variety of sequences, whose evolutionary origin has been puzzling for several decades. At present, the key questions concerning the driving force behind their rapid evolution and the means of co-evolution of telomeric repeats and telomere-binding proteins remain largely unanswered. Previously published studies addressed mostly the general concepts of the evolutionary origin of telomeres, key properties of telomeric proteins as well as the molecular mechanisms of telomere maintenance; however, the evolutionary process itself has not been analyzed thoroughly. Here, we aimed to inspect the evolution of telomeres in ascomycetous yeasts from the subphyla Saccharomycotina and Taphrinomycotina, with special focus on the evolutionary origin of species-specific telomeric repeats. We analyzed the sequences of telomeric repeats from 204 yeast species classified into 20 families and as a result, we propose a step-by-step model, which integrates the diversity of telomeric repeats, telomerase RNAs, telomere-binding protein complexes and explains a propensity of certain species to generate the repeat heterogeneity within a single telomeric array.
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Affiliation(s)
- Filip Červenák
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Regina Sepšiová
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Jozef Nosek
- Department of Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Ľubomír Tomáška
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
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15
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Jurikova K, Gajarsky M, Hajikazemi M, Nosek J, Prochazkova K, Paeschke K, Trantirek L, Tomaska L. Role of folding kinetics of secondary structures in telomeric G-overhangs in the regulation of telomere maintenance in Saccharomyces cerevisiae. J Biol Chem 2020; 295:8958-8971. [PMID: 32385108 PMCID: PMC7335780 DOI: 10.1074/jbc.ra120.012914] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/07/2020] [Indexed: 12/15/2022] Open
Abstract
The ends of eukaryotic chromosomes typically contain a 3' ssDNA G-rich protrusion (G-overhang). This overhang must be protected against detrimental activities of nucleases and of the DNA damage response machinery and participates in the regulation of telomerase, a ribonucleoprotein complex that maintains telomere integrity. These functions are mediated by DNA-binding proteins, such as Cdc13 in Saccharomyces cerevisiae, and the propensity of G-rich sequences to form various non-B DNA structures. Using CD and NMR spectroscopies, we show here that G-overhangs of S. cerevisiae form distinct Hoogsteen pairing-based secondary structures, depending on their length. Whereas short telomeric oligonucleotides form a G-hairpin, their longer counterparts form parallel and/or antiparallel G-quadruplexes (G4s). Regardless of their topologies, non-B DNA structures exhibited impaired binding to Cdc13 in vitro as demonstrated by electrophoretic mobility shift assays. Importantly, whereas G4 structures formed relatively quickly, G-hairpins folded extremely slowly, indicating that short G-overhangs, which are typical for most of the cell cycle, are present predominantly as single-stranded oligonucleotides and are suitable substrates for Cdc13. Using ChIP, we show that the occurrence of G4 structures peaks at the late S phase, thus correlating with the accumulation of long G-overhangs. We present a model of how time- and length-dependent formation of non-B DNA structures at chromosomal termini participates in telomere maintenance.
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Affiliation(s)
- Katarina Jurikova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Martin Gajarsky
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Mona Hajikazemi
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Katarina Prochazkova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Katrin Paeschke
- Department of Oncology, Hematology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Lukas Trantirek
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic.
| | - Lubomir Tomaska
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia.
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16
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Dew-Budd K, Cheung J, Palos K, Forsythe ES, Beilstein MA. Evolutionary and biochemical analyses reveal conservation of the Brassicaceae telomerase ribonucleoprotein complex. PLoS One 2020; 15:e0222687. [PMID: 32271752 PMCID: PMC7145096 DOI: 10.1371/journal.pone.0222687] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/22/2020] [Indexed: 11/27/2022] Open
Abstract
The telomerase ribonucleoprotein complex (RNP) is essential for genome stability and performs this role through the addition of repetitive DNA to the ends of chromosomes. The telomerase enzyme is composed of a reverse transcriptase (TERT), which utilizes a template domain in an RNA subunit (TER) to reiteratively add telomeric DNA at the ends of chromosomes. Multiple TERs have been identified in the model plant Arabidopsis thaliana. Here we combine a phylogenetic and biochemical approach to understand how the telomerase RNP has evolved in Brassicaceae, the family that includes A. thaliana. Because of the complex phylogenetic pattern of template domain loss and alteration at the previously characterized A. thaliana TER loci, TER1 and TER2, across the plant family Brassicaceae, we bred double mutants from plants with a template deletion at AtTER1 and T-DNA insertion at AtTER2. These double mutants exhibited no telomere length deficiency, a definitive indication that neither of these loci encode a functional telomerase RNA. Moreover, we determined that the telomerase components TERT, Dyskerin, and the KU heterodimer are under strong purifying selection, consistent with the idea that the TER with which they interact is also conserved. To test this hypothesis further, we analyzed the substrate specificity of telomerase from species across Brassicaceae and determined that telomerase from close relatives bind and extend substrates in a similar manner, supporting the idea that TERs in different species are highly similar to one another and are likely encoded from an orthologous locus. Lastly, TERT proteins from across Brassicaceae were able to complement loss of function tert mutants in vivo, indicating TERTs from other species have the ability to recognize the native TER of A. thaliana. Finally, we immunoprecipitated the telomerase complex and identified associated RNAs via RNA-seq. Using our evolutionary data we constrained our analyses to conserved RNAs within Brassicaceae that contained a template domain. These analyses revealed a highly expressed locus whose disruption by a T-DNA resulted in a telomeric phenotype similar to the loss of other telomerase core proteins, indicating that the RNA has an important function in telomere maintenance.
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Affiliation(s)
- Kelly Dew-Budd
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Julie Cheung
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Kyle Palos
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Evan S. Forsythe
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Mark A. Beilstein
- School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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17
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Tomáška Ľ, Nosek J. Co-evolution in the Jungle: From Leafcutter Ant Colonies to Chromosomal Ends. J Mol Evol 2020; 88:293-318. [PMID: 32157325 DOI: 10.1007/s00239-020-09935-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/25/2020] [Indexed: 02/06/2023]
Abstract
Biological entities are multicomponent systems where each part is directly or indirectly dependent on the others. In effect, a change in a single component might have a consequence on the functioning of its partners, thus affecting the fitness of the entire system. In this article, we provide a few examples of such complex biological systems, ranging from ant colonies to a population of amino acids within a single-polypeptide chain. Based on these examples, we discuss one of the central and still challenging questions in biology: how do such multicomponent consortia co-evolve? More specifically, we ask how telomeres, nucleo-protein complexes protecting the integrity of linear DNA chromosomes, originated from the ancestral organisms having circular genomes and thus not dealing with end-replication and end-protection problems. Using the examples of rapidly evolving topologies of mitochondrial genomes in eukaryotic microorganisms, we show what means of co-evolution were employed to accommodate various types of telomere-maintenance mechanisms in mitochondria. We also describe an unprecedented runaway evolution of telomeric repeats in nuclei of ascomycetous yeasts accompanied by co-evolution of telomere-associated proteins. We propose several scenarios derived from research on telomeres and supported by other studies from various fields of biology, while emphasizing that the relevant answers are still not in sight. It is this uncertainty and a lack of a detailed roadmap that makes the journey through the jungle of biological systems still exciting and worth undertaking.
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Affiliation(s)
- Ľubomír Tomáška
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia.
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15, Bratislava, Slovakia
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18
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Fajkus P, Peška V, Závodník M, Fojtová M, Fulnečková J, Dobias Š, Kilar A, Dvořáčková M, Zachová D, Nečasová I, Sims J, Sýkorová E, Fajkus J. Telomerase RNAs in land plants. Nucleic Acids Res 2019; 47:9842-9856. [PMID: 31392988 PMCID: PMC6765143 DOI: 10.1093/nar/gkz695] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 02/07/2023] Open
Abstract
To elucidate the molecular nature of evolutionary changes of telomeres in the plant order Asparagales, we aimed to characterize telomerase RNA subunits (TRs) in these plants. The unusually long telomere repeat unit in Allium plants (12 nt) allowed us to identify TRs in transcriptomic data of representative species of the Allium genus. Orthologous TRs were then identified in Asparagales plants harbouring telomere DNA composed of TTAGGG (human type) or TTTAGGG (Arabidopsis-type) repeats. Further, we identified TRs across the land plant phylogeny, including common model plants, crop plants, and plants with unusual telomeres. Several lines of functional testing demonstrate the templating telomerase function of the identified TRs and disprove a functionality of the only previously reported plant telomerase RNA in Arabidopsis thaliana. Importantly, our results change the existing paradigm in plant telomere biology which has been based on the existence of a relatively conserved telomerase reverse transcriptase subunit (TERT) associating with highly divergent TRs even between closely related plant taxa. The finding of a monophyletic origin of genuine TRs across land plants opens the possibility to identify TRs directly in transcriptomic or genomic data and/or predict telomere sequences synthesized according to the respective TR template region.
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Affiliation(s)
- Petr Fajkus
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Vratislav Peška
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic
| | - Michal Závodník
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Miloslava Fojtová
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Jana Fulnečková
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Šimon Dobias
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Agata Kilar
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Dagmar Zachová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Ivona Nečasová
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
| | - Jason Sims
- Max Perutz Labs, University of Vienna, Dr. Bohr Gasse 9, A-1030, Vienna, Austria
| | - Eva Sýkorová
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic
| | - Jiří Fajkus
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno CZ-61265, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic.,Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno CZ-62500, Czech Republic
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19
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Červenák F, Juríková K, Devillers H, Kaffe B, Khatib A, Bonnell E, Sopkovičová M, Wellinger RJ, Nosek J, Tzfati Y, Neuvéglise C, Tomáška Ľ. Identification of telomerase RNAs in species of the Yarrowia clade provides insights into the co-evolution of telomerase, telomeric repeats and telomere-binding proteins. Sci Rep 2019; 9:13365. [PMID: 31527614 PMCID: PMC6746865 DOI: 10.1038/s41598-019-49628-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
Telomeric repeats in fungi of the subphylum Saccharomycotina exhibit great inter- and intra-species variability in length and sequence. Such variations challenged telomeric DNA-binding proteins that co-evolved to maintain their functions at telomeres. Here, we compare the extent of co-variations in telomeric repeats, encoded in the telomerase RNAs (TERs), and the repeat-binding proteins from 13 species belonging to the Yarrowia clade. We identified putative TER loci, analyzed their sequence and secondary structure conservation, and predicted functional elements. Moreover, in vivo complementation assays with mutant TERs showed the functional importance of four novel TER substructures. The TER-derived telomeric repeat unit of all species, except for one, is 10 bp long and can be represented as 5′-TTNNNNAGGG-3′, with repeat sequence variations occuring primarily outside the vertebrate telomeric motif 5′-TTAGGG-3′. All species possess a homologue of the Yarrowia lipolytica Tay1 protein, YlTay1p. In vitro, YlTay1p displays comparable DNA-binding affinity to all repeat variants, suggesting a conserved role among these species. Taken together, these results add significant insights into the co-evolution of TERs, telomeric repeats and telomere-binding proteins in yeasts.
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Affiliation(s)
- Filip Červenák
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Katarína Juríková
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Hugo Devillers
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Binyamin Kaffe
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Areej Khatib
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Erin Bonnell
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Martina Sopkovičová
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Raymund J Wellinger
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Jozef Nosek
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel.
| | - Cécile Neuvéglise
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
| | - Ľubomír Tomáška
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia.
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20
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Abstract
Patients with suppressed immunity are at the highest risk for hospital-acquired infections. Among these, invasive candidiasis is the most prevalent systemic fungal nosocomial infection. Over recent decades, the combined prevalence of non-albicans Candida species outranked Candida albicans infections in several geographical regions worldwide, highlighting the need to understand their pathobiology in order to develop effective treatment and to prevent future outbreaks. Candida parapsilosis is the second or third most frequently isolated Candida species from patients. Besides being highly prevalent, its biology differs markedly from that of C. albicans, which may be associated with C. parapsilosis' increased incidence. Differences in virulence, regulatory and antifungal drug resistance mechanisms, and the patient groups at risk indicate that conclusions drawn from C. albicans pathobiology cannot be simply extrapolated to C. parapsilosis Such species-specific characteristics may also influence their recognition and elimination by the host and the efficacy of antifungal drugs. Due to the availability of high-throughput, state-of-the-art experimental tools and molecular genetic methods adapted to C. parapsilosis, genome and transcriptome studies are now available that greatly contribute to our understanding of what makes this species a threat. In this review, we summarize 10 years of findings on C. parapsilosis pathogenesis, including the species' genetic properties, transcriptome studies, host responses, and molecular mechanisms of virulence. Antifungal susceptibility studies and clinician perspectives are discussed. We also present regional incidence reports in order to provide an updated worldwide epidemiology summary.
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21
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Telomeres in Plants and Humans: Not So Different, Not So Similar. Cells 2019; 8:cells8010058. [PMID: 30654521 PMCID: PMC6356271 DOI: 10.3390/cells8010058] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 01/01/2023] Open
Abstract
Parallel research on multiple model organisms shows that while some principles of telomere biology are conserved among all eukaryotic kingdoms, we also find some deviations that reflect different evolutionary paths and life strategies, which may have diversified after the establishment of telomerase as a primary mechanism for telomere maintenance. Much more than animals, plants have to cope with environmental stressors, including genotoxic factors, due to their sessile lifestyle. This is, in principle, made possible by an increased capacity and efficiency of the molecular systems ensuring maintenance of genome stability, as well as a higher tolerance to genome instability. Furthermore, plant ontogenesis differs from that of animals in which tissue differentiation and telomerase silencing occur during early embryonic development, and the “telomere clock” in somatic cells may act as a preventive measure against carcinogenesis. This does not happen in plants, where growth and ontogenesis occur through the serial division of apical meristems consisting of a small group of stem cells that generate a linear series of cells, which differentiate into an array of cell types that make a shoot and root. Flowers, as generative plant organs, initiate from the shoot apical meristem in mature plants which is incompatible with the human-like developmental telomere shortening. In this review, we discuss differences between human and plant telomere biology and the implications for aging, genome stability, and cell and organism survival. In particular, we provide a comprehensive comparative overview of telomere proteins acting in humans and in Arabidopsis thaliana model plant, and discuss distinct epigenetic features of telomeric chromatin in these species.
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22
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Tomáška Ĺ, Nosek J, Sepšiová R, Červenák F, Juríková K, Procházková K, Neboháčová M, Willcox S, Griffith JD. Commentary: Single-stranded telomere-binding protein employs a dual rheostat for binding affinity and specificity that drives function. Front Genet 2019; 9:742. [PMID: 30697232 PMCID: PMC6341069 DOI: 10.3389/fgene.2018.00742] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/22/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Ĺubomír Tomáška
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Regina Sepšiová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Filip Červenák
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Katarína Juríková
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Katarína Procházková
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Martina Neboháčová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, United States
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, United States
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23
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Brejová B, Lichancová H, Brázdovič F, Hegedűsová E, Forgáčová Jakúbková M, Hodorová V, Džugasová V, Baláž A, Zeiselová L, Cillingová A, Neboháčová M, Raclavský V, Tomáška Ľ, Lang BF, Vinař T, Nosek J. Genome sequence of the opportunistic human pathogen Magnusiomyces capitatus. Curr Genet 2018; 65:539-560. [PMID: 30456648 DOI: 10.1007/s00294-018-0904-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 01/12/2023]
Abstract
The yeast Magnusiomyces capitatus is an opportunistic human pathogen causing rare yet severe infections, especially in patients with hematological malignancies. Here, we report the 20.2 megabase genome sequence of an environmental strain of this species as well as the genome sequences of eight additional isolates from human and animal sources providing an insight into intraspecies variation. The distribution of single-nucleotide variants is indicative of genetic recombination events, supporting evidence for sexual reproduction in this heterothallic yeast. Using RNAseq-aided annotation, we identified genes for 6518 proteins including several expanded families such as kexin proteases and Hsp70 molecular chaperones. Several of these families are potentially associated with the ability of M. capitatus to infect and colonize humans. For the purpose of comparative analysis, we also determined the genome sequence of a closely related yeast, Magnusiomyces ingens. The genome sequences of M. capitatus and M. ingens exhibit many distinct features and represent a basis for further comparative and functional studies.
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Affiliation(s)
- Bronislava Brejová
- Faculty of Mathematics, Physics, and Informatics, Comenius University in Bratislava, Bratislava, Slovakia.
| | - Hana Lichancová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Filip Brázdovič
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Eva Hegedűsová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia.,Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | | | - Viktória Hodorová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Vladimíra Džugasová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Andrej Baláž
- Faculty of Mathematics, Physics, and Informatics, Comenius University in Bratislava, Bratislava, Slovakia
| | - Lucia Zeiselová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Andrea Cillingová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Martina Neboháčová
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Vladislav Raclavský
- Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Ľubomír Tomáška
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - B Franz Lang
- Robert Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
| | - Tomáš Vinař
- Faculty of Mathematics, Physics, and Informatics, Comenius University in Bratislava, Bratislava, Slovakia
| | - Jozef Nosek
- Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia.
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24
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Laterreur N, Lemieux B, Neumann H, Berger-Dancause JC, Lafontaine D, Wellinger RJ. The yeast telomerase module for telomere recruitment requires a specific RNA architecture. RNA (NEW YORK, N.Y.) 2018; 24:1067-1079. [PMID: 29777050 PMCID: PMC6049500 DOI: 10.1261/rna.066696.118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Telomerases are ribonucleoprotein (RNP) reverse transcriptases. While telomerases maintain genome stability, their composition varies significantly between species. Yeast telomerase RNPs contain an RNA that is comparatively large, and its overall folding shows long helical segments with distal functional parts. Here we investigated the essential stem IVc module of the budding yeast telomerase RNA, called Tlc1. The distal part of stem IVc includes a conserved sequence element CS2a and structurally conserved features for binding Pop1/Pop6/Pop7 proteins, which together function analogously to the P3 domains of the RNase P/MRP RNPs. A more proximal bulged stem with the CS2 element is thought to associate with Est1, a telomerase protein required for telomerase recruitment to telomeres. Previous work found that changes in CS2a cause a loss of all stem IVc proteins, not just the Pop proteins. Here we show that the association of Est1 with stem IVc indeed requires both the proximal bulged stem and the P3 domain with the associated Pop proteins. Separating the P3 domain from the Est1 binding site by inserting only 2 base pairs into the helical stem between the two sites causes a complete loss of Est1 from the RNP and hence a telomerase-negative phenotype in vivo. Still, the distal P3 domain with the associated Pop proteins remains intact. Moreover, the P3 domain ensures Est2 stability on the RNP independently of Est1 association. Therefore, the Tlc1 stem IVc recruitment module of the RNA requires a very tight architectural organization for telomerase function in vivo.
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Affiliation(s)
- Nancy Laterreur
- Department of Microbiology and Infectiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, PRAC, Sherbrooke, Québec J1E 4K8, Canada
| | - Bruno Lemieux
- Department of Microbiology and Infectiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, PRAC, Sherbrooke, Québec J1E 4K8, Canada
| | - Hannah Neumann
- Department of Microbiology and Infectiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, PRAC, Sherbrooke, Québec J1E 4K8, Canada
| | | | - Daniel Lafontaine
- Department of Biology, Faculty of Sciences, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Raymund J Wellinger
- Department of Microbiology and Infectiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, PRAC, Sherbrooke, Québec J1E 4K8, Canada
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25
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Waldl M, Thiel BC, Ochsenreiter R, Holzenleiter A, de Araujo Oliveira JV, Walter MEMT, Wolfinger MT, Stadler PF. TERribly Difficult: Searching for Telomerase RNAs in Saccharomycetes. Genes (Basel) 2018; 9:genes9080372. [PMID: 30049970 PMCID: PMC6115765 DOI: 10.3390/genes9080372] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 11/20/2022] Open
Abstract
The telomerase RNA in yeasts is large, usually >1000 nt, and contains functional elements that have been extensively studied experimentally in several disparate species. Nevertheless, they are very difficult to detect by homology-based methods and so far have escaped annotation in the majority of the genomes of Saccharomycotina. This is a consequence of sequences that evolve rapidly at nucleotide level, are subject to large variations in size, and are highly plastic with respect to their secondary structures. Here, we report on a survey that was aimed at closing this gap in RNA annotation. Despite considerable efforts and the combination of a variety of different methods, it was only partially successful. While 27 new telomerase RNAs were identified, we had to restrict our efforts to the subgroup Saccharomycetacea because even this narrow subgroup was diverse enough to require different search models for different phylogenetic subgroups. More distant branches of the Saccharomycotina remain without annotated telomerase RNA.
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Affiliation(s)
- Maria Waldl
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria.
| | - Bernhard C Thiel
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria.
| | - Roman Ochsenreiter
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria.
| | - Alexander Holzenleiter
- BioInformatics Group, Fakultät CB Hochschule Mittweida, Technikumplatz 17, D-09648 Mittweida, Germany.
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstraße 16-18, D-04107 Leipzig, Germany.
| | - João Victor de Araujo Oliveira
- Departamento de Ciência da Computação, Instituto de Ciências Exatas, Universidade de Brasília, Campus Universitário⁻Asa Norte, Brasília, DF CEP: 70910-900, Brazil.
| | - Maria Emília M T Walter
- Departamento de Ciência da Computação, Instituto de Ciências Exatas, Universidade de Brasília, Campus Universitário⁻Asa Norte, Brasília, DF CEP: 70910-900, Brazil.
| | - Michael T Wolfinger
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria.
- Center for Anatomy and Cell Biology, Medical University of Vienna, Währingerstraße 13, 1090 Vienna, Austria.
| | - Peter F Stadler
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria.
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions, and Leipzig Research Center for Civilization Diseases, Universität Leipzig, D-04107 Leipzig, Germany.
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany.
- Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM 87501, USA.
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26
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Páez-Moscoso DJ, Pan L, Sigauke RF, Schroeder MR, Tang W, Baumann P. Pof8 is a La-related protein and a constitutive component of telomerase in fission yeast. Nat Commun 2018; 9:587. [PMID: 29422664 PMCID: PMC5805746 DOI: 10.1038/s41467-017-02284-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/17/2017] [Indexed: 01/06/2023] Open
Abstract
Telomerase reverse transcriptase (TERT) and the non-coding telomerase RNA subunit (TR) constitute the core of telomerase. Here we now report that the putative F-box protein Pof8 is also a constitutive component of active telomerase in fission yeast. Pof8 functions in a hierarchical assembly pathway by promoting the binding of the Lsm2-8 complex to telomerase RNA, which in turn promotes binding of the catalytic subunit. Loss of Pof8 reduces TER1 stability, causes a severe assembly defect, and results in critically short telomeres. Structure profile searches identified similarities between Pof8 and telomerase subunits from ciliated protozoa, making Pof8 next to TERT the most widely conserved telomerase subunits identified to date.
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Affiliation(s)
| | - Lili Pan
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | | | | | - Wen Tang
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA.,RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Peter Baumann
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA. .,Howard Hughes Medical Institute, Kansas City, MO, 64110, USA. .,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, MO, 66160, USA. .,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, 55099, Mainz, Germany.
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27
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Hsu M, Lue NF. Analysis of Yeast Telomerase by Primer Extension Assays. Methods Mol Biol 2018; 1587:83-93. [PMID: 28324500 DOI: 10.1007/978-1-4939-6892-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Telomeres are specialized nucleoprotein structures located at eukaryotic chromosomal termini, which are required for chromosome stability and are maintained by a reverse transcriptase named telomerase. Budding yeast has served as an extremely useful model system for analyzing telomere maintenance because the organism offers a wide range of genetic and biochemical tools. Several milestones in telomerase research have been reached through investigation of the yeast system. For example, the consequence of telomerase loss was first characterized in the budding yeast Saccharomyces cerevisiae. The catalytic component of telomerase (telomerase reverse transcriptase; TERT) was likewise initially cloned from this organism. Moreover, much of the current understanding of the structure and function of the telomerase complex was derived from yeast studies. In this chapter, we discuss one of the most useful tools for investigating yeast telomerase mechanisms and regulation: the primer extension assay. This assay can be used to examine the overall activity as well as the processivity of telomerase, which represents a unique aspect of telomerase enzymology. It can also be employed to analyze the mechanisms of telomerase regulatory proteins.
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Affiliation(s)
- Min Hsu
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY, 10021, USA
| | - Neal F Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY, 10021, USA.
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28
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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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29
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Laterreur N, Wellinger RJ. [A rejuvenation for yeast telomerase]. Med Sci (Paris) 2017; 33:1051-1054. [PMID: 29261492 DOI: 10.1051/medsci/20173312011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Nancy Laterreur
- Département de microbiologie et infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3201 Rue Jean Mignault Sherbrooke, Québec, J1E 4K8, Canada
| | - Raymund J Wellinger
- Département de microbiologie et infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3201 Rue Jean Mignault Sherbrooke, Québec, J1E 4K8, Canada
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30
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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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31
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Červenák F, Juríková K, Sepšiová R, Neboháčová M, Nosek J, Tomáška L. Double-stranded telomeric DNA binding proteins: Diversity matters. Cell Cycle 2017; 16:1568-1577. [PMID: 28749196 DOI: 10.1080/15384101.2017.1356511] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Telomeric sequences constitute only a small fraction of the whole genome yet they are crucial for ensuring genomic stability. This function is in large part mediated by protein complexes recruited to telomeric sequences by specific telomere-binding proteins (TBPs). Although the principal tasks of nuclear telomeres are the same in all eukaryotes, TBPs in various taxa exhibit a surprising diversity indicating their distinct evolutionary origin. This diversity is especially pronounced in ascomycetous yeasts where they must have co-evolved with rapidly diversifying sequences of telomeric repeats. In this article we (i) provide a historical overview of the discoveries leading to the current list of TBPs binding to double-stranded (ds) regions of telomeres, (ii) describe examples of dsTBPs highlighting their diversity in even closely related species, and (iii) speculate about possible evolutionary trajectories leading to a long list of various dsTBPs fulfilling the same general role(s) in their own unique ways.
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Affiliation(s)
- Filip Červenák
- a Department of Genetics , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
| | - Katarína Juríková
- a Department of Genetics , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
| | - Regina Sepšiová
- a Department of Genetics , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
| | - Martina Neboháčová
- b Department of Biochemistry , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
| | - Jozef Nosek
- b Department of Biochemistry , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
| | - L'ubomír Tomáška
- a Department of Genetics , Comenius University in Bratislava, Faculty of Natural Sciences , Bratislava , Slovakia
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32
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Allegra A, Innao V, Penna G, Gerace D, Allegra AG, Musolino C. Telomerase and telomere biology in hematological diseases: A new therapeutic target. Leuk Res 2017; 56:60-74. [PMID: 28196338 DOI: 10.1016/j.leukres.2017.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/24/2017] [Accepted: 02/05/2017] [Indexed: 11/29/2022]
Abstract
Telomeres are structures confined at the ends of eukaryotic chromosomes. With each cell division, telomeric repeats are lost because DNA polymerases are incapable to fully duplicate the very ends of linear chromosomes. Loss of repeats causes cell senescence, and apoptosis. Telomerase neutralizes loss of telomeric sequences by adding telomere repeats at the 3' telomeric overhang. Telomere biology is frequently associated with human cancer and dysfunctional telomeres have been proved to participate to genetic instability. This review covers the information on telomerase expression and genetic alterations in the most relevant types of hematological diseases. Telomere erosion hampers the capability of hematopoietic stem cells to effectively replicate, clinically resulting in bone marrow failure. Furthermore, telomerase mutations are genetic risk factors for the occurrence of some hematologic cancers. New discoveries in telomere structure and telomerase functions have led to an increasing interest in targeting telomeres and telomerase in anti-cancer therapy.
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Affiliation(s)
- Alessandro Allegra
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy.
| | - Vanessa Innao
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy
| | - Giuseppa Penna
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy
| | - Demetrio Gerace
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy
| | - Andrea G Allegra
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy
| | - Caterina Musolino
- Dipartimento di Patologia Umana dell'Adulto e dell'Età Evolutiva "Gaetano Barresi", University of Messina Via Consolare Valeria, 1, 98125 Messina, Italy
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33
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Vasianovich Y, Wellinger RJ. Life and Death of Yeast Telomerase RNA. J Mol Biol 2017; 429:3242-3254. [PMID: 28115201 DOI: 10.1016/j.jmb.2017.01.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/10/2017] [Accepted: 01/14/2017] [Indexed: 12/20/2022]
Abstract
Telomerase reverse transcriptase elongates telomeres to overcome their natural attrition and allow unlimited cellular proliferation, a characteristic shared by stem cells and the majority of malignant cancerous cells. The telomerase holoenzyme comprises a core RNA molecule, a catalytic protein subunit, and other accessory proteins. Malfunction of certain telomerase components can cause serious genetic disorders including dyskeratosis congenita and aplastic anaemia. A hierarchy of tightly regulated steps constitutes the process of telomerase biogenesis, which, if interrupted or misregulated, can impede the production of a functional enzyme and severely affect telomere maintenance. Here, we take a closer look at the budding yeast telomerase RNA component, TLC1, in its long lifetime journey around the cell. We review the extensive knowledge on TLC1 transcription and processing. We focus on exciting recent studies on telomerase assembly, trafficking, and nuclear dynamics, which for the first time unveil striking similarities between the yeast and human telomerase ribonucleoproteins. Finally, we identify questions yet to be answered and new directions to be followed, which, in the future, might improve our knowledge of telomerase biology and trigger the development of new therapies against cancer and other telomerase-related diseases.
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Affiliation(s)
- Yulia Vasianovich
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Applied Cancer Research Pavillion, 3201 rue Jean-Mignault, Sherbrooke, Quebec, J1E 4K8, Canada.
| | - Raymund J Wellinger
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Applied Cancer Research Pavillion, 3201 rue Jean-Mignault, Sherbrooke, Quebec, J1E 4K8, Canada.
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34
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Xu C, Ishikawa H, Izumikawa K, Li L, He H, Nobe Y, Yamauchi Y, Shahjee HM, Wu XH, Yu YT, Isobe T, Takahashi N, Min J. Structural insights into Gemin5-guided selection of pre-snRNAs for snRNP assembly. Genes Dev 2016; 30:2376-2390. [PMID: 27881600 PMCID: PMC5131778 DOI: 10.1101/gad.288340.116] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/26/2016] [Indexed: 12/26/2022]
Abstract
Xu et al. show that the WD40 domain of Gemin5 is both necessary and sufficient for binding the Sm site of pre-snRNAs. They also determined the crystal structures of the WD40 domain of Gemin5 in complex with the Sm site or m7G cap of pre-snRNA. In cytoplasm, the survival of motor neuron (SMN) complex delivers pre-small nuclear RNAs (pre-snRNAs) to the heptameric Sm ring for the assembly of the ring complex on pre-snRNAs at the conserved Sm site [A(U)4–6G]. Gemin5, a WD40 protein component of the SMN complex, is responsible for recognizing pre-snRNAs. In addition, Gemin5 has been reported to specifically bind to the m7G cap. In this study, we show that the WD40 domain of Gemin5 is both necessary and sufficient for binding the Sm site of pre-snRNAs by isothermal titration calorimetry (ITC) and mutagenesis assays. We further determined the crystal structures of the WD40 domain of Gemin5 in complex with the Sm site or m7G cap of pre-snRNA, which reveal that the WD40 domain of Gemin5 recognizes the Sm site and m7G cap of pre-snRNAs via two distinct binding sites by respective base-specific interactions. In addition, we also uncovered a novel role of Gemin5 in escorting the truncated forms of U1 pre-snRNAs for proper disposal. Overall, the elucidated Gemin5 structures will contribute to a better understanding of Gemin5 in small nuclear ribonucleic protein (snRNP) biogenesis as well as, potentially, other cellular activities.
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Affiliation(s)
- Chao Xu
- Hefei National Laboratory for Physical Sciences at Microscale, Hefei Science Center of CAS, Chinese Academy of Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.,Key Laboratory of Structural Biology, Hefei Science Center of CAS, Chinese Academy of Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.,Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Hideaki Ishikawa
- Department of Applied Biological Science, Graduate School of Agriculture and Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Fuchu-Shi, Tokyo 183-8509, Japan
| | - Keiichi Izumikawa
- Department of Applied Biological Science, Graduate School of Agriculture and Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Fuchu-Shi, Tokyo 183-8509, Japan
| | - Li Li
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Hao He
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Yuko Nobe
- Department of Chemistry, Tokyo Metropolitan University, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Yoshio Yamauchi
- Department of Chemistry, Tokyo Metropolitan University, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Hanief M Shahjee
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Xian-Hui Wu
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | - Toshiaki Isobe
- Department of Chemistry, Tokyo Metropolitan University, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Nobuhiro Takahashi
- Department of Applied Biological Science, Graduate School of Agriculture and Global Innovation Research Organization, Tokyo University of Agriculture and Technology, Fuchu-Shi, Tokyo 183-8509, Japan
| | - Jinrong Min
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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MacNeil DE, Bensoussan HJ, Autexier C. Telomerase Regulation from Beginning to the End. Genes (Basel) 2016; 7:genes7090064. [PMID: 27649246 PMCID: PMC5042394 DOI: 10.3390/genes7090064] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 12/11/2022] Open
Abstract
The vast body of literature regarding human telomere maintenance is a true testament to the importance of understanding telomere regulation in both normal and diseased states. In this review, our goal was simple: tell the telomerase story from the biogenesis of its parts to its maturity as a complex and function at its site of action, emphasizing new developments and how they contribute to the foundational knowledge of telomerase and telomere biology.
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Affiliation(s)
- Deanna Elise MacNeil
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
| | - Hélène Jeanne Bensoussan
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
| | - Chantal Autexier
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
- Department of Experimental Medicine, McGill University, 1110 Pins Avenue West, Room 101, Montréal, QC H3A 1A3, Canada.
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Peška V, Sitová Z, Fajkus P, Fajkus J. BAL31-NGS approach for identification of telomeres de novo in large genomes. Methods 2016; 114:16-27. [PMID: 27595912 DOI: 10.1016/j.ymeth.2016.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/22/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022] Open
Abstract
This article describes a novel method to identify as yet undiscovered telomere sequences, which combines next generation sequencing (NGS) with BAL31 digestion of high molecular weight DNA. The method was applied to two groups of plants: i) dicots, genus Cestrum, and ii) monocots, Allium species (e.g. A. ursinum and A. cepa). Both groups consist of species with large genomes (tens of Gb) and a low number of chromosomes (2n=14-16), full of repeat elements. Both genera lack typical telomeric repeats and multiple studies have attempted to characterize alternative telomeric sequences. However, despite interesting hypotheses and suggestions of alternative candidate telomeres (retrotransposons, rDNA, satellite repeats) these studies have not resolved the question. In a novel approach based on the two most general features of eukaryotic telomeres, their repetitive character and sensitivity to BAL31 nuclease digestion, we have taken advantage of the capacity and current affordability of NGS in combination with the robustness of classical BAL31 nuclease digestion of chromosomal termini. While representative samples of most repeat elements were ensured by low-coverage (less than 5%) genomic shot-gun NGS, candidate telomeres were identified as under-represented sequences in BAL31-treated samples.
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Affiliation(s)
- Vratislav Peška
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic
| | - Zdeňka Sitová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
| | - Petr Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic.
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37
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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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38
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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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Abstract
The addition of telomeric DNA to chromosome ends is an essential cellular activity that compensates for the loss of genomic DNA that is due to the inability of the conventional DNA replication apparatus to duplicate the entire chromosome. The telomerase reverse transcriptase and its associated RNA bind to the very end of the telomere via a sequence in the RNA and specific protein-protein interactions. Telomerase RNA also provides the template for addition of new telomeric repeats by the reverse-transcriptase protein subunit. In addition to the template, there are 3 other conserved regions in telomerase RNA that are essential for normal telomerase activity. Here we briefly review the conserved core regions of telomerase RNA and then focus on a recent study in fission yeast that determined the function of another conserved region in telomerase RNA called the Stem Terminus Element (STE). (1) The STE is distant from the templating core of telomerase in both the linear and RNA secondary structure, but, nonetheless, affects the fidelity of telomere sequence addition and, in turn, the ability of telomere binding proteins to bind and protect chromosome ends. We will discuss possible mechanisms of STE action and the suitability of the STE as an anti-cancer target.
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Affiliation(s)
- Christopher J Webb
- a Department of Molecular Biology , Princeton University , Princeton , NJ , USA
| | - Virginia A Zakian
- a Department of Molecular Biology , Princeton University , Princeton , NJ , USA
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40
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Lemieux B, Laterreur N, Perederina A, Noël JF, Dubois ML, Krasilnikov AS, Wellinger RJ. Active Yeast Telomerase Shares Subunits with Ribonucleoproteins RNase P and RNase MRP. Cell 2016; 165:1171-1181. [PMID: 27156450 DOI: 10.1016/j.cell.2016.04.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/20/2016] [Accepted: 04/01/2016] [Indexed: 01/01/2023]
Abstract
Telomerase is the ribonucleoprotein enzyme that replenishes telomeric DNA and maintains genome integrity. Minimally, telomerase activity requires a templating RNA and a catalytic protein. Additional proteins are required for activity on telomeres in vivo. Here, we report that the Pop1, Pop6, and Pop7 proteins, known components of RNase P and RNase MRP, bind to yeast telomerase RNA and are essential constituents of the telomerase holoenzyme. Pop1/Pop6/Pop7 binding is specific and involves an RNA domain highly similar to a protein-binding domain in the RNAs of RNase P/MRP. The results also show that Pop1/Pop6/Pop7 function to maintain the essential components Est1 and Est2 on the RNA in vivo. Consistently, addition of Pop1 allows for telomerase activity reconstitution with wild-type telomerase RNA in vitro. Thus, the same chaperoning module has allowed the evolution of functionally and, remarkably, structurally distinct RNPs, telomerase, and RNases P/MRP from unrelated progenitor RNAs.
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Affiliation(s)
- Bruno Lemieux
- Department of Microbiology and Infectious Diseases, Center of Excellence in RNA Biology, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Nancy Laterreur
- Department of Microbiology and Infectious Diseases, Center of Excellence in RNA Biology, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Anna Perederina
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jean-François Noël
- Department of Microbiology and Infectious Diseases, Center of Excellence in RNA Biology, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Marie-Line Dubois
- Department of Anatomy and Cellular Biology,Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Andrey S Krasilnikov
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Raymund J Wellinger
- Department of Microbiology and Infectious Diseases, Center of Excellence in RNA Biology, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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Sepsiova R, Necasova I, Willcox S, Prochazkova K, Gorilak P, Nosek J, Hofr C, Griffith JD, Tomaska L. Evolution of Telomeres in Schizosaccharomyces pombe and Its Possible Relationship to the Diversification of Telomere Binding Proteins. PLoS One 2016; 11:e0154225. [PMID: 27101289 PMCID: PMC4839565 DOI: 10.1371/journal.pone.0154225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 04/11/2016] [Indexed: 11/30/2022] Open
Abstract
Telomeres of nuclear chromosomes are usually composed of an array of tandemly repeated sequences that are recognized by specific Myb domain containing DNA-binding proteins (telomere-binding proteins, TBPs). Whereas in many eukaryotes the length and sequence of the telomeric repeat is relatively conserved, telomeric sequences in various yeasts are highly variable. Schizosaccharomyces pombe provides an excellent model for investigation of co-evolution of telomeres and TBPs. First, telomeric repeats of S. pombe differ from the canonical mammalian type TTAGGG sequence. Second, S. pombe telomeres exhibit a high degree of intratelomeric heterogeneity. Third, S. pombe contains all types of known TBPs (Rap1p [a version unable to bind DNA], Tay1p/Teb1p, and Taz1p) that are employed by various yeast species to protect their telomeres. With the aim of reconstructing evolutionary paths leading to a separation of roles between Teb1p and Taz1p, we performed a comparative analysis of the DNA-binding properties of both proteins using combined qualitative and quantitative biochemical approaches. Visualization of DNA-protein complexes by electron microscopy revealed qualitative differences of binding of Teb1p and Taz1p to mammalian type and fission yeast telomeres. Fluorescence anisotropy analysis quantified the binding affinity of Teb1p and Taz1p to three different DNA substrates. Additionally, we carried out electrophoretic mobility shift assays using mammalian type telomeres and native substrates (telomeric repeats, histone-box sequences) as well as their mutated versions. We observed relative DNA sequence binding flexibility of Taz1p and higher binding stringency of Teb1p when both proteins were compared directly to each other. These properties may have driven replacement of Teb1p by Taz1p as the TBP in fission yeast.
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Affiliation(s)
- Regina Sepsiova
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Ivona Necasova
- Chromatin Molecular Complexes, Central European Institute of Technology, Masaryk University, Brno, CZ-62500, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, CZ-62500, Czech Republic
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States of America
| | - Katarina Prochazkova
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Peter Gorilak
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Jozef Nosek
- Department of Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
| | - Ctirad Hofr
- Chromatin Molecular Complexes, Central European Institute of Technology, Masaryk University, Brno, CZ-62500, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, CZ-62500, Czech Republic
| | - Jack D. Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States of America
| | - Lubomir Tomaska
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic
- * E-mail:
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Podlevsky JD, Li Y, Chen JJL. Structure and function of echinoderm telomerase RNA. RNA (NEW YORK, N.Y.) 2016; 22:204-215. [PMID: 26598712 PMCID: PMC4712671 DOI: 10.1261/rna.053280.115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/23/2015] [Indexed: 06/05/2023]
Abstract
Telomerase is a ribonucleoprotein (RNP) enzyme that requires an integral telomerase RNA (TR) subunit, in addition to the catalytic telomerase reverse transcriptase (TERT), for enzymatic function. The secondary structures of TRs from the three major groups of species, ciliates, fungi, and vertebrates, have been studied extensively and demonstrate dramatic diversity. Herein, we report the first comprehensive secondary structure of TR from echinoderms-marine invertebrates closely related to vertebrates-determined by phylogenetic comparative analysis of 16 TR sequences from three separate echinoderm classes. Similar to vertebrate TR, echinoderm TR contains the highly conserved template/pseudoknot and H/ACA domains. However, echinoderm TR lacks the ancestral CR4/5 structural domain found throughout vertebrate and fungal TRs. Instead, echinoderm TR contains a distinct simple helical region, termed eCR4/5, that is functionally equivalent to the CR4/5 domain. The urchin and brittle star eCR4/5 domains bind specifically to their respective TERT proteins and stimulate telomerase activity. Distinct from vertebrate telomerase, the echinoderm TR template/pseudoknot domain with the TERT protein is sufficient to reconstitute significant telomerase activity. This gain-of-function of the echinoderm template/pseudoknot domain for conferring telomerase activity presumably facilitated the rapid structural evolution of the eCR4/5 domain throughout the echinoderm lineage. Additionally, echinoderm TR utilizes the template-adjacent P1.1 helix as a physical template boundary element to prevent nontelomeric DNA synthesis, a mechanism used by ciliate and fungal TRs. Thus, the chimeric and eccentric structural features of echinoderm TR provide unparalleled insights into the rapid evolution of telomerase RNP structure and function.
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Affiliation(s)
- Joshua D Podlevsky
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Yang Li
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Julian J-L Chen
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, USA
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43
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Tseng CK, Wang HF, Burns A, Schroeder M, Gaspari M, Baumann P. Human Telomerase RNA Processing and Quality Control. Cell Rep 2015; 13:2232-43. [DOI: 10.1016/j.celrep.2015.10.075] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/02/2015] [Accepted: 10/27/2015] [Indexed: 12/11/2022] Open
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44
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Pryszcz LP, Németh T, Saus E, Ksiezopolska E, Hegedűsová E, Nosek J, Wolfe KH, Gacser A, Gabaldón T. The Genomic Aftermath of Hybridization in the Opportunistic Pathogen Candida metapsilosis. PLoS Genet 2015; 11:e1005626. [PMID: 26517373 PMCID: PMC4627764 DOI: 10.1371/journal.pgen.1005626] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/05/2015] [Indexed: 01/17/2023] Open
Abstract
Candida metapsilosis is a rarely-isolated, opportunistic pathogen that belongs to a clade of pathogenic yeasts known as the C. parapsilosis sensu lato species complex. To gain insight into the recent evolution of C. metapsilosis and the genetic basis of its virulence, we sequenced the genome of 11 clinical isolates from various locations, which we compared to each other and to the available genomes of the two remaining members of the complex: C. orthopsilosis and C. parapsilosis. Unexpectedly, we found compelling genomic evidence that C. metapsilosis is a highly heterozygous hybrid species, with all sequenced clinical strains resulting from the same past hybridization event involving two parental lineages that were approximately 4.5% divergent in sequence. This result indicates that the parental species are non-pathogenic, but that hybridization between them formed a new opportunistic pathogen, C. metapsilosis, that has achieved a worldwide distribution. We show that these hybrids are diploid and we identified strains carrying loci for both alternative mating types, which supports mating as the initial mechanism for hybrid formation. We trace the aftermath of this hybridization at the genomic level, and reconstruct the evolutionary relationships among the different strains. Recombination and introgression -resulting in loss of heterozygosis- between the two subgenomes have been rampant, and includes the partial overwriting of the MTLa mating locus in all strains. Collectively, our results shed light on the recent genomic evolution within the C. parapsilosis sensu lato complex, and argue for a re-definition of species within this clade, with at least five distinct homozygous lineages, some of which having the ability to form hybrids.
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Affiliation(s)
- Leszek P. Pryszcz
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Tibor Németh
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Ester Saus
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Ewa Ksiezopolska
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Eva Hegedűsová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Kenneth H. Wolfe
- UCD Conway Institute, School of Medicine & Medical Science, University College Dublin, Dublin, Ireland
| | - Attila Gacser
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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45
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Steinberg-Neifach O, Wellington K, Vazquez L, Lue NF. Combinatorial recognition of a complex telomere repeat sequence by the Candida parapsilosis Cdc13AB heterodimer. Nucleic Acids Res 2015; 43:2164-76. [PMID: 25662607 PMCID: PMC4344524 DOI: 10.1093/nar/gkv092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The telomere repeat units of Candida species are substantially longer and more complex than those in other organisms, raising interesting questions concerning the recognition mechanisms of telomere-binding proteins. Herein we characterized the properties of Candida parapsilosis Cdc13A and Cdc13B, two paralogs that are responsible for binding and protecting the telomere G-strand tails. We found that Cdc13A and Cdc13B can each form complexes with itself and a heterodimeric complex with each other. However, only the heterodimer exhibits high-affinity and sequence-specific binding to the telomere G-tail. EMSA and crosslinking analysis revealed a combinatorial mechanism of DNA recognition, which entails the A and B subunit making contacts to the 3′ and 5′ region of the repeat unit. While both the DBD and OB4 domain of Cdc13A can bind to the equivalent domain in Cdc13B, only the OB4 complex behaves as a stable heterodimer. The unstable Cdc13ABDBD complex binds G-strand with greatly reduced affinity but the same sequence specificity. Thus the OB4 domains evidently contribute to binding by promoting dimerization of the DBDs. Our investigation reveals a rare example of combinatorial recognition of single-stranded DNA and offers insights into the co-evolution of telomere DNA and cognate binding proteins.
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Affiliation(s)
- Olga Steinberg-Neifach
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
- Hostos Community College, City University of New York, 500 Grand Concourse, Bronx, NY 10451, USA
| | - Kemar Wellington
- Hostos Community College, City University of New York, 500 Grand Concourse, Bronx, NY 10451, USA
| | - Leslie Vazquez
- Hostos Community College, City University of New York, 500 Grand Concourse, Bronx, NY 10451, USA
| | - Neal F. Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
- To whom correspondence should be addressed. Tel: +1 212 746 6506; Fax: +1 212 746 8587;
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Lebo KJ, Niederer RO, Zappulla DC. A second essential function of the Est1-binding arm of yeast telomerase RNA. RNA (NEW YORK, N.Y.) 2015; 21:862-876. [PMID: 25737580 PMCID: PMC4408794 DOI: 10.1261/rna.049379.114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 12/29/2014] [Indexed: 06/04/2023]
Abstract
The enzymatic ribonucleoprotein telomerase maintains telomeres in many eukaryotes, including humans, and plays a central role in aging and cancer. Saccharomyces cerevisiae telomerase RNA, TLC1, is a flexible scaffold that tethers telomerase holoenzyme protein subunits to the complex. Here we test the hypothesis that a lengthy conserved region of the Est1-binding TLC1 arm contributes more than simply Est1-binding function. We separated Est1 binding from potential other functions by tethering TLC1 to Est1 via a heterologous RNA-protein binding module. We find that Est1-tethering rescues in vivo function of telomerase RNA alleles missing nucleotides specifically required for Est1 binding, but not those missing the entire conserved region. Notably, however, telomerase function is restored for this condition by expressing the arm of TLC1 in trans. Mutational analysis shows that the Second Essential Est1-arm Domain (SEED) maps to an internal loop of the arm, which SHAPE chemical mapping and 3D modeling suggest could be regulated by conformational change. Finally, we find that the SEED has an essential, Est1-independent role in telomerase function after telomerase recruitment to the telomere. The SEED may be required for establishing telomere extendibility or promoting telomerase RNP holoenzyme activity.
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Affiliation(s)
- Kevin J Lebo
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
| | - Rachel O Niederer
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
| | - David C Zappulla
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218-2685, USA
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47
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Školáková P, Foldynová-Trantírková S, Bednářová K, Fiala R, Vorlíčková M, Trantírek L. Unique C. elegans telomeric overhang structures reveal the evolutionarily conserved properties of telomeric DNA. Nucleic Acids Res 2015; 43:4733-45. [PMID: 25855805 PMCID: PMC4482068 DOI: 10.1093/nar/gkv296] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 03/25/2015] [Indexed: 11/16/2022] Open
Abstract
There are two basic mechanisms that are associated with the maintenance of the telomere length, which endows cancer cells with unlimited proliferative potential. One mechanism, referred to as alternative lengthening of telomeres (ALT), accounts for approximately 10–15% of all human cancers. Tumours engaged in the ALT pathway are characterised by the presence of the single stranded 5′-C-rich telomeric overhang (C-overhang). This recently identified hallmark of ALT cancers distinguishes them from healthy tissues and renders the C-overhang as a clear target for anticancer therapy. We analysed structures of the 5′-C-rich and 3′-G-rich telomeric overhangs from human and Caenorhabditis elegans, the recently established multicellular in vivo model of ALT tumours. We show that the telomeric DNA from C. elegans and humans forms fundamentally different secondary structures. The unique structural characteristics of C. elegans telomeric DNA that are distinct not only from those of humans but also from those of other multicellular eukaryotes allowed us to identify evolutionarily conserved properties of telomeric DNA. Differences in structural organisation of the telomeric DNA between the C. elegans and human impose limitations on the use of the C. elegans as an ALT tumour model.
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Affiliation(s)
- Petra Školáková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska, 135, 612 65 Brno, Czech Republic
| | - Silvie Foldynová-Trantírková
- Central European Institute of Technology, Masaryk University, Kamenice 735/5, 625 00 Brno, Czech Republic Institute of Parasitology, Academy of Sciences of the Czech Republic, Branisovska, 31, 375 05 Ceske Budejovice, Czech Republic
| | - Klára Bednářová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska, 135, 612 65 Brno, Czech Republic Central European Institute of Technology, Masaryk University, Kamenice 735/5, 625 00 Brno, Czech Republic
| | - Radovan Fiala
- Central European Institute of Technology, Masaryk University, Kamenice 735/5, 625 00 Brno, Czech Republic
| | - Michaela Vorlíčková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska, 135, 612 65 Brno, Czech Republic Central European Institute of Technology, Masaryk University, Kamenice 735/5, 625 00 Brno, Czech Republic
| | - Lukáš Trantírek
- Central European Institute of Technology, Masaryk University, Kamenice 735/5, 625 00 Brno, Czech Republic
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Niederer RO, Zappulla DC. Refined secondary-structure models of the core of yeast and human telomerase RNAs directed by SHAPE. RNA (NEW YORK, N.Y.) 2015; 21:254-261. [PMID: 25512567 PMCID: PMC4338352 DOI: 10.1261/rna.048959.114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/14/2014] [Indexed: 06/04/2023]
Abstract
Telomerase catalyzes the addition of nucleotides to the ends of chromosomes to complete genomic DNA replication in eukaryotes and is implicated in multiple diseases, including most cancers. The core enzyme is composed of a reverse transcriptase and an RNA subunit, which provides the template for DNA synthesis. Despite extensive divergence at the sequence level, telomerase RNAs share several structural features within the catalytic core, suggesting a conserved enzyme mechanism. We have investigated the structure of the core of the human and yeast telomerase RNAs using SHAPE, which interrogates flexibility of each nucleotide. We present improved secondary-structure models, refined by addition of five base triples within the yeast pseudoknot and an alternate pairing within the human-specific element J2a.1 in the human pseudoknot, both of which have implications for thermodynamic stability. We also identified a potentially structured CCC region within the template that may facilitate substrate binding and enzyme mechanism. Overall, the SHAPE findings reveal multiple similarities between the Saccharomyces cerevisiae and Homo sapiens telomerase RNA cores.
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Affiliation(s)
- Rachel O Niederer
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - David C Zappulla
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Prevalent and distinct spliceosomal 3'-end processing mechanisms for fungal telomerase RNA. Nat Commun 2015; 6:6105. [PMID: 25598218 PMCID: PMC4299825 DOI: 10.1038/ncomms7105] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 12/15/2014] [Indexed: 11/19/2022] Open
Abstract
Telomerase RNA (TER) is an essential component of the telomerase ribonucleoprotein complex. The mechanism for TER 3′-end processing is highly divergent among different organisms. Here we report a unique spliceosome-mediated TER 3′-end cleavage mechanism in Neurospora crassa which is distinct from that found specifically in the fission yeast Schizosaccharomyces pombe. While the S. pombe TER intron contains the canonical 5′-splice site GUAUGU, the N. crassa TER intron contains a non-canonical 5′-splice site AUAAGU that alone prevents the second step of splicing and promotes spliceosomal cleavage. The unique N. crassa TER 5′-splice site sequence is evolutionarily conserved in TERs from Pezizomycotina and early branching Taphrinomycotina species. This suggests that the widespread and basal N. crassa-type spliceosomal cleavage mechanism is more ancestral than the S. pombe-type. The discovery of a prevalent, yet distinct, spliceosomal cleavage mechanism throughout diverse fungal clades furthers our understanding of TER evolution and non-coding RNA processing.
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50
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Kannan R, Helston RM, Dannebaum RO, Baumann P. Diverse mechanisms for spliceosome-mediated 3' end processing of telomerase RNA. Nat Commun 2015; 6:6104. [PMID: 25598145 PMCID: PMC4299874 DOI: 10.1038/ncomms7104] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 12/15/2014] [Indexed: 11/13/2022] Open
Abstract
The 3′ end of Schizosaccharomyces pombe telomerase RNA (SpTER1) is generated by spliceosomal cleavage, a reaction that corresponds to the first step of splicing. The observation that the spliceosome functions in 3′ end processing raised questions about the evolutionary origin and conservation of this mechanism. We now present data in support of spliceosomes generating 3′ ends of telomerase RNAs in other fungi. Strikingly, the mechanistic basis for restricting spliceosomal splicing to the first transesterification reaction differs substantially among species. Unlike S. pombe, two other fission yeasts rely on hyperstabilization of the U6 snRNA—5′ splice site interaction to impede the 2nd step of splicing. In contrast, a non-canonical 5′ splice site blocks the second transesterification reaction in Aspergillus species. These results demonstrate a conserved role for spliceosomes functioning in 3′ end processing. Divergent mechanisms of uncoupling the two steps of splicing argue for multiple origins of this pathway. In fission yeast, the telomerase RNA (TER) is produced through spliceosomal cleavage. Here, Kannan et al. find that spliceosome-generated 3′ ends also occurs in other fungal TERs using distinct molecular mechanisms, suggesting multiple origins for this type of TER maturation pathway.
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Affiliation(s)
- Ram Kannan
- 1] Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA [2] Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - Rachel M Helston
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | | | - Peter Baumann
- 1] Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA [2] Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA [3] Howard Hughes Medical Institute, Kansas City, Missouri 64110, USA
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