1
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Valeeva LR, Sannikova AV, Shafigullina NR, Abdulkina LR, Sharipova MR, Shakirov EV. Telomere Length Variation in Model Bryophytes. PLANTS (BASEL, SWITZERLAND) 2024; 13:387. [PMID: 38337920 PMCID: PMC10856949 DOI: 10.3390/plants13030387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024]
Abstract
The ends of linear chromosomes of most eukaryotes consist of protein-bound DNA arrays called telomeres, which play essential roles in protecting genome integrity. Despite general evolutionary conservation in function, telomeric DNA is known to drastically vary in length and sequence between different eukaryotic lineages. Bryophytes are a group of early diverging land plants that include mosses, liverworts, and hornworts. This group of ancient land plants recently emerged as a new model for important discoveries in genomics and evolutionary biology, as well as for understanding plant adaptations to a terrestrial lifestyle. We measured telomere length in different ecotypes of model bryophyte species, including Physcomitrium patens, Marchantia polymorpha, Ceratodon purpureus, and in Sphagnum isolates. Our data indicate that all analyzed moss and liverwort genotypes have relatively short telomeres. Furthermore, all analyzed ecotypes and isolates of model mosses and liverworts display evidence of substantial natural variation in telomere length. Interestingly, telomere length also differs between male and female strains of the dioecious liverwort M. polymorpha and dioecious moss C. purpureus. Given that bryophytes are extraordinarily well adapted to different ecological niches from polar to tropical environments, our data will contribute to understanding the impact of natural telomere length variation on evolutionary adaptations in this ancient land plant lineage.
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Affiliation(s)
- Liia R. Valeeva
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia; (A.V.S.); (L.R.A.)
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
| | - Anastasia V. Sannikova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia; (A.V.S.); (L.R.A.)
| | - Nadiya R. Shafigullina
- Institute of Environmental Sciences, Department of General Ecology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia
| | - Liliia R. Abdulkina
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia; (A.V.S.); (L.R.A.)
| | - Margarita R. Sharipova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Republic of Tatarstan, Russia; (A.V.S.); (L.R.A.)
| | - Eugene V. Shakirov
- Department of Biological Sciences, College of Science, Marshall University, Huntington, WV 25701, USA
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
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2
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Barcenilla BB, Meyers AD, Castillo-González C, Young P, Min JH, Song J, Phadke C, Land E, Canaday E, Perera IY, Bailey SM, Aquilano R, Wyatt SE, Shippen DE. Arabidopsis telomerase takes off by uncoupling enzyme activity from telomere length maintenance in space. Nat Commun 2023; 14:7854. [PMID: 38030615 PMCID: PMC10686995 DOI: 10.1038/s41467-023-41510-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/07/2023] [Indexed: 12/01/2023] Open
Abstract
Spaceflight-induced changes in astronaut telomeres have garnered significant attention in recent years. While plants represent an essential component of future long-duration space travel, the impacts of spaceflight on plant telomeres and telomerase have not been examined. Here we report on the telomere dynamics of Arabidopsis thaliana grown aboard the International Space Station. We observe no changes in telomere length in space-flown Arabidopsis seedlings, despite a dramatic increase in telomerase activity (up to 150-fold in roots), as well as elevated genome oxidation. Ground-based follow up studies provide further evidence that telomerase is induced by different environmental stressors, but its activity is uncoupled from telomere length. Supporting this conclusion, genetically engineered super-telomerase lines with enhanced telomerase activity maintain wildtype telomere length. Finally, genome oxidation is inversely correlated with telomerase activity levels. We propose a redox protective capacity for Arabidopsis telomerase that may promote survivability in harsh environments.
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Affiliation(s)
- Borja Barbero Barcenilla
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Alexander D Meyers
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA
- NASA Postdoctoral Program, Oak Ridge Associated Universities, Kennedy Space Center FL, Merritt Island, FL, 32899, USA
| | - Claudia Castillo-González
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Pierce Young
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Ji-Hee Min
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Jiarui Song
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Chinmay Phadke
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Eric Land
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Emma Canaday
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA
| | - Imara Y Perera
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Susan M Bailey
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Roberto Aquilano
- National Technological University, Rosario Regional Faculty, Zeballos 1341, S2000, Rosario, Argentina
| | - Sarah E Wyatt
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA.
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA.
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA.
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3
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Závodník M, Fajkus P, Franek M, Kopecký D, Garcia S, Dodsworth S, Orejuela A, Kilar A, Ptáček J, Mátl M, Hýsková A, Fajkus J, Peška V. Telomerase RNA gene paralogs in plants - the usual pathway to unusual telomeres. THE NEW PHYTOLOGIST 2023; 239:2353-2366. [PMID: 37391893 DOI: 10.1111/nph.19110] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/06/2023] [Indexed: 07/02/2023]
Abstract
Telomerase, telomeric DNA and associated proteins together represent a complex, finely tuned and functionally conserved mechanism that ensures genome integrity by protecting and maintaining chromosome ends. Changes in its components can threaten an organism's viability. Nevertheless, molecular innovation in telomere maintenance has occurred multiple times during eukaryote evolution, giving rise to species/taxa with unusual telomeric DNA sequences, telomerase components or telomerase-independent telomere maintenance. The central component of telomere maintenance machinery is telomerase RNA (TR) as it templates telomere DNA synthesis, its mutation can change telomere DNA and disrupt its recognition by telomere proteins, thereby leading to collapse of their end-protective and telomerase recruitment functions. Using a combination of bioinformatic and experimental approaches, we examine a plausible scenario of evolutionary changes in TR underlying telomere transitions. We identified plants harbouring multiple TR paralogs whose template regions could support the synthesis of diverse telomeres. In our hypothesis, formation of unusual telomeres is associated with the occurrence of TR paralogs that can accumulate mutations, and through their functional redundancy, allow for the adaptive evolution of the other telomere components. Experimental analyses of telomeres in the examined plants demonstrate evolutionary telomere transitions corresponding to TR paralogs with diverse template regions.
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Affiliation(s)
- 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
| | - Petr Fajkus
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno, CZ-62500, Czech Republic
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno, CZ-61265, Czech Republic
| | - Michal Franek
- Mendel Centre for Plant Genomics and Proteomics, CEITEC Masaryk University, Brno, CZ-62500, Czech Republic
| | - David Kopecký
- Centre of Plant Structural and Functional Genomics, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, CZ-779 00, Czech Republic
| | - Sònia Garcia
- Institut Botànic de Barcelona (IBB-CSIC), Passeig del Migdia S/N, Barcelona, 08038, Catalonia, Spain
| | - Steven Dodsworth
- School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry I St., Portsmouth, PO1 2DY, UK
| | - Andrés Orejuela
- Grupo de Investigación en Recursos Naturales Amazónicos - GRAM, Facultad de Ingenierías y Ciencias Básicas and Herbario Etnobotánico del Piedemonte Andino Amazónico (HEAA), Instituto Tecnológico del Putumayo - ITP, Mocoa, Putumayo, Colombia
| | - 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
| | - Jiří Ptáček
- Potato Research Institute Havlíčkův Brod Ltd, Havlíčkův Brod, CZ-58001, Czech Republic
| | - Martin Mátl
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno, CZ-61265, Czech Republic
| | - Anna Hýsková
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, CZ-61137, Czech Republic
| | - Jiří Fajkus
- 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
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno, CZ-61265, Czech Republic
| | - Vratislav Peška
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Brno, CZ-61265, Czech Republic
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4
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Konečná KP, Kilar A, Kováčiková P, Fajkus J, Sýkorová E, Fojtová M. Compromised function of ARM, the interactor of Arabidopsis telomerase, suggests its role in stress responses. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 325:111453. [PMID: 36087885 DOI: 10.1016/j.plantsci.2022.111453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/02/2022] [Accepted: 09/03/2022] [Indexed: 06/15/2023]
Abstract
ARM was identified previously as an interaction partner of the telomerase protein subunit (TERT) in Arabidopsis thaliana. To investigate the interconnection between ARM and telomerase and to identify ARM cellular functions, we analyzed a set of arm mutant lines and arm/tert double mutants. Telomere length was not affected in arm single mutant plants, in contrast to double mutants. In the second generation of homozygous arm-1/tert double mutants following the heterozygous state during the double mutant construction, telomeres shortened dramatically, even below levels in tert plants displaying severe morphological defects. Intriguingly, homozygous arm-1/tert double mutants with short telomeres grew without obvious phenotypic changes for next two generations. Then, in agreement with the onset of phenotypic changes in tert, morphological defects were timed to the 5th arm-1/tert homozygous generation. RNAseq analyses of arm-1/tert and respective single mutants displayed markedly overlapping sets of differentially expressed genes in arm-1/tert double mutant and arm-1 single mutant lines, indicating a dominant effect of the ARM mutation. RNAseq data further implied ARM involvement in circadian rhythms, responses to drugs and to biotic and abiotic stimuli. In agreement with it, we observed sensitivity of arm-1 single mutant to the heat stress during germination. Altogether, our results suggest ARM involvement in crucial cellular processes without evidencing its role in the telomerase canonical function.
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Affiliation(s)
- Klára Přikrylová Konečná
- Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic; Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Agata Kilar
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Petra Kováčiková
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic; Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic.
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5
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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6
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Choi JY, Abdulkina LR, Yin J, Chastukhina IB, Lovell JT, Agabekian IA, Young PG, Razzaque S, Shippen DE, Juenger TE, Shakirov EV, Purugganan MD. Natural variation in plant telomere length is associated with flowering time. THE PLANT CELL 2021; 33:1118-1134. [PMID: 33580702 PMCID: PMC8599780 DOI: 10.1093/plcell/koab022] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/14/2021] [Indexed: 05/05/2023]
Abstract
Telomeres are highly repetitive DNA sequences found at the ends of chromosomes that protect the chromosomes from deterioration duringcell division. Here, using whole-genome re-sequencing and terminal restriction fragment assays, we found substantial natural intraspecific variation in telomere length in Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays). Genome-wide association study (GWAS) mapping in A. thaliana identified 13 regions with GWAS-significant associations underlying telomere length variation, including a region that harbors the telomerase reverse transcriptase (TERT) gene. Population genomic analysis provided evidence for a selective sweep at the TERT region associated with longer telomeres. We found that telomere length is negatively correlated with flowering time variation not only in A. thaliana, but also in maize and rice, indicating a link between life-history traits and chromosome integrity. Our results point to several possible reasons for this correlation, including the possibility that longer telomeres may be more adaptive in plants that have faster developmental rates (and therefore flower earlier). Our work suggests that chromosomal structure itself might be an adaptive trait associated with plant life-history strategies.
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Affiliation(s)
- Jae Young Choi
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York 10003, NY, USA
- Author for correspondence: (J.Y.C), (E.V.S.) or (M.D.P.)
| | - Liliia R Abdulkina
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan 420008, Russia
| | - Jun Yin
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA
| | - Inna B Chastukhina
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan 420008, Russia
| | - John T Lovell
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Alabama 35806, USA
| | - Inna A Agabekian
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan 420008, Russia
| | - Pierce G Young
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, USA
| | - Samsad Razzaque
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, Texas 77843-2128, USA
| | - Thomas E Juenger
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA
| | - Eugene V Shakirov
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Republic of Tatarstan 420008, Russia
- Department of Biological Sciences, College of Science, Marshall University, West Virginia 25701, USA
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, West Virginia 25755, USA
- Author for correspondence: (J.Y.C), (E.V.S.) or (M.D.P.)
| | - Michael D Purugganan
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York 10003, NY, USA
- Author for correspondence: (J.Y.C), (E.V.S.) or (M.D.P.)
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D'Amico-Willman KM, Anderson ES, Gradziel TM, Fresnedo-Ramírez J. Relative Telomere Length and Telomerase Reverse Transcriptase (TERT) Expression Are Associated with Age in Almond ( Prunus dulcis [Mill.] D.A.Webb). PLANTS (BASEL, SWITZERLAND) 2021; 10:189. [PMID: 33498228 PMCID: PMC7909263 DOI: 10.3390/plants10020189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 01/02/2023]
Abstract
While all organisms age, our understanding of how aging occurs varies among species. The aging process in perennial plants is not well-defined, yet can have implications on production and yield of valuable fruit and nut crops. Almond exhibits an age-related disorder known as non-infectious bud failure (BF) that affects vegetative bud development, indirectly affecting kernel yield. This species and disorder present an opportunity to address aging in a commercially relevant and vegetatively propagated perennial crop. The hypothesis tested in this study was that relative telomere length and/or telomerase reverse transcriptase (TERT) expression can serve as biomarkers of aging in almond. Relative telomere lengths and expression of TERT, a subunit of the enzyme telomerase, were measured via qPCR methods using bud and leaf samples collected from distinct age cohorts over a two-year period. Results from this work show a marginal but significant association between both relative telomere length and TERT expression, and age, suggesting that as almonds age, telomeres shorten and TERT expression decreases. This work provides information on potential biomarkers of perennial plant aging, contributing to our knowledge of this process. In addition, these results provide opportunities to address BF in almond breeding and nursery propagation.
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Affiliation(s)
- Katherine M. D'Amico-Willman
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 446911, USA;
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 432102, USA
| | | | - Thomas M. Gradziel
- Department of Plant Sciences, University of California, Davis, CA 95616, USA;
| | - Jonathan Fresnedo-Ramírez
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 446911, USA;
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 432102, USA
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8
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Teymouri M, Parvini Kohneh Shahri M, Darvishzadeh R. Salt-Induced Differences During the Gene Expression of Telomerase Enzyme in Sunflower. IRANIAN JOURNAL OF BIOTECHNOLOGY 2021; 19:e2579. [PMID: 34179190 PMCID: PMC8217534 DOI: 10.30498/ijb.2021.2579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background: Salinity is one of the most important environmental stresses which reduces the nutrient uptake, growth and yield of crops including sunflower. Objectives: The aim of this study was evaluating the expression pattern of telomerase gene, TERT, in sunflower plants under salinity stress. Materials and Methods: Sunflower plants of both sensitive and resistant lines were grown in greenhouse and treated with different levels of NaCl (2, 5 and 8 dSm-1).
The expression pattern of TERT gene was evaluated at 8th leaf stage 6, 12 and 24 hours post salt treatment using real time-PCR,
since the effects of salt stress are eventually manifested in the leaves. Results: In both lines, salt-subjected plants showed reduced size and dried leaves, due to breakthrough of the growth.
Compared to the control group, treated groups tended to indicate downregulated pattern of TERT gene expression. Conclusions: This study offers TERT as a new gene affected by salt stress when growth is arrested.
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Affiliation(s)
- Mahdi Teymouri
- Department of Biology, Urmia Branch, Islamic Azad University, Urmia, Iran
| | | | - Reza Darvishzadeh
- Department of Biology, Urmia Branch, Islamic Azad University, Urmia, Iran.,Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources,Urmia University, Urmia, Iran
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9
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Sun S, Yi C, Ma J, Wang S, Peirats-Llobet M, Lewsey MG, Whelan J, Shou H. Analysis of Spatio-Temporal Transcriptome Profiles of Soybean ( Glycine max) Tissues during Early Seed Development. Int J Mol Sci 2020; 21:E7603. [PMID: 33066688 PMCID: PMC7589660 DOI: 10.3390/ijms21207603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 01/17/2023] Open
Abstract
Soybean (Glycine max) is an important crop providing oil and protein for both human and animal consumption. Knowing which biological processes take place in specific tissues in a temporal manner will enable directed breeding or synthetic approaches to improve seed quantity and quality. We analyzed a genome-wide transcriptome dataset from embryo, endosperm, endothelium, epidermis, hilum, outer and inner integument and suspensor at the global, heart and cotyledon stages of soybean seed development. The tissue specificity of gene expression was greater than stage specificity, and only three genes were differentially expressed in all seed tissues. Tissues had both unique and shared enriched functional categories of tissue-specifically expressed genes associated with them. Strong spatio-temporal correlation in gene expression was identified using weighted gene co-expression network analysis, with the most co-expression occurring in one seed tissue. Transcription factors with distinct spatiotemporal gene expression programs in each seed tissue were identified as candidate regulators of expression within those tissues. Gene ontology (GO) enrichment of orthogroup clusters revealed the conserved functions and unique roles of orthogroups with similar and contrasting expression patterns in transcript abundance between soybean and Arabidopsis during embryo proper and endosperm development. Key regulators in each seed tissue and hub genes connecting those networks were characterized by constructing gene regulatory networks. Our findings provide an important resource for describing the structure and function of individual soybean seed compartments during early seed development.
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Affiliation(s)
- Shuo Sun
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; (S.S.); (J.M.)
| | - Changyu Yi
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia; (C.Y.); (M.P.-L.)
| | - Jing Ma
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; (S.S.); (J.M.)
| | - Shoudong Wang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Changchun 130102, China;
| | - Marta Peirats-Llobet
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia; (C.Y.); (M.P.-L.)
| | - Mathew G. Lewsey
- Department of Animal, Plant and Soil Science, AgriBio Building, La Trobe University, Bundoora, Victoria 3086, Australia;
- Australian Research Council Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, Victoria 3086, Australia
| | - James Whelan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; (S.S.); (J.M.)
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia; (C.Y.); (M.P.-L.)
- Australian Research Council Research Hub for Medicinal Agriculture, AgriBio Building, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Huixia Shou
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; (S.S.); (J.M.)
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10
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Functional Diversification of Replication Protein A Paralogs and Telomere Length Maintenance in Arabidopsis. Genetics 2020; 215:989-1002. [PMID: 32532801 DOI: 10.1534/genetics.120.303222] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022] Open
Abstract
Replication protein A (RPA) is essential for many facets of DNA metabolism. The RPA gene family expanded in Arabidopsis thaliana with five phylogenetically distinct RPA1 subunits (RPA1A-E), two RPA2 (RPA2A and B), and two RPA3 (RPA3A and B). RPA1 paralogs exhibit partial redundancy and functional specialization in DNA replication (RPA1B and RPA1D), repair (RPA1C and RPA1E), and meiotic recombination (RPA1A and RPA1C). Here, we show that RPA subunits also differentially impact telomere length set point. Loss of RPA1 resets bulk telomeres at a shorter length, with a functional hierarchy for replication group over repair and meiosis group RPA1 subunits. Plants lacking RPA2A, but not RPA2B, harbor short telomeres similar to the replication group. Telomere shortening does not correlate with decreased telomerase activity or deprotection of chromosome ends in rpa mutants. However, in vitro assays show that RPA1B2A3B unfolds telomeric G-quadruplexes known to inhibit replications fork progression. We also found that ATR deficiency can partially rescue short telomeres in rpa2a mutants, although plants exhibit defects in growth and development. Unexpectedly, the telomere shortening phenotype of rpa2a mutants is completely abolished in plants lacking the RTEL1 helicase. RTEL1 has been implicated in a variety of nucleic acid transactions, including suppression of homologous recombination. Thus, the lack of telomere shortening in rpa2a mutants upon RTEL1 deletion suggests that telomere replication defects incurred by loss of RPA may be bypassed by homologous recombination. Taken together, these findings provide new insight into how RPA cooperates with replication and recombination machinery to sustain telomeric DNA.
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11
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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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12
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De la Torre-Espinosa ZY, Barredo-Pool F, Castaño de la Serna E, Sánchez-Teyer LF. Active telomerase during leaf growth and increase of age in plants from Agave tequilana var. Azul. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:639-647. [PMID: 32255928 PMCID: PMC7113356 DOI: 10.1007/s12298-020-00781-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/28/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
In plants, previous studies show that telomerase activity contributes to the maintenance of telomeric length for the proper development of organs and tissues. In this work, we investigated telomerase activity in A. tequilana during several years of cultivation. We found that during growth of the leaf there are two crucial phases: (1) the onset of cell elongation in 3 years and (2) differentiation of vascular bundles in 6 years. This coincides with the ages where the highest telomerase activity is seen. Therefore indicates that telomerase is associated with cellular activities such as; elongation, division, and cell differentiation. Likewise, we detected high activity during the period of vegetative growth, indicating that telomerase also contributes to telomeric maintenance on the leaf in A. tequilana.
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Affiliation(s)
- Zamaria Yoselin De la Torre-Espinosa
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Felipe Barredo-Pool
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Enrique Castaño de la Serna
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Lorenzo Felipe Sánchez-Teyer
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
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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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A telomerase with novel non-canonical roles: TERT controls cellular aggregation and tissue size in Dictyostelium. PLoS Genet 2019; 15:e1008188. [PMID: 31237867 PMCID: PMC6592521 DOI: 10.1371/journal.pgen.1008188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/10/2019] [Indexed: 11/19/2022] Open
Abstract
Telomerase, particularly its main subunit, the reverse transcriptase, TERT, prevents DNA erosion during eukaryotic chromosomal replication, but also has poorly understood non-canonical functions. Here, in the model social amoeba Dictyostelium discoideum, we show that the protein encoded by tert has telomerase-like motifs, and regulates, non-canonically, important developmental processes. Expression levels of wild-type (WT) tert were biphasic, peaking at 8 and 12 h post-starvation, aligning with developmental events, such as the initiation of streaming (~7 h) and mound formation (~10 h). In tert KO mutants, however, aggregation was delayed until 16 h. Large, irregular streams formed, then broke up, forming small mounds. The mound-size defect was not induced when a KO mutant of countin (a master size-regulating gene) was treated with TERT inhibitors, but anti-countin antibodies did rescue size in the tert KO. Although, conditioned medium (CM) from countin mutants failed to rescue size in the tert KO, tert KO CM rescued the countin KO phenotype. These and additional observations indicate that TERT acts upstream of smlA/countin: (i) the observed expression levels of smlA and countin, being respectively lower and higher (than WT) in the tert KO; (ii) the levels of known size-regulation intermediates, glucose (low) and adenosine (high), in the tert mutant, and the size defect's rescue by supplemented glucose or the adenosine-antagonist, caffeine; (iii) the induction of the size defect in the WT by tert KO CM and TERT inhibitors. The tert KO's other defects (delayed aggregation, irregular streaming) were associated with changes to cAMP-regulated processes (e.g. chemotaxis, cAMP pulsing) and their regulatory factors (e.g. cAMP; acaA, carA expression). Overexpression of WT tert in the tert KO rescued these defects (and size), and restored a single cAMP signaling centre. Our results indicate that TERT acts in novel, non-canonical and upstream ways, regulating key developmental events in Dictyostelium.
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15
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Schořová Š, Fajkus J, Záveská Drábková L, Honys D, Schrumpfová PP. The plant Pontin and Reptin homologues, RuvBL1 and RuvBL2a, colocalize with TERT and TRB proteins in vivo, and participate in telomerase biogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:195-212. [PMID: 30834599 DOI: 10.1111/tpj.14306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 05/15/2023]
Abstract
Telomerase maturation and recruitment to telomeres is regulated by several telomerase- and telomere-associated proteins. Among a number of proteins, human Pontin and Reptin play critical roles in telomerase biogenesis. Here we characterized plant orthologues of Pontin and Reptin, RuvBL1 and RuvBL2a, respectively, and show association of Arabidopsis thaliana RuvBL1 (AtRuvBL1) with the catalytic subunit of telomerase (AtTERT) in the nucleolus in vivo. In contrast to mammals, interactions between AtTERT and AtRuvBL proteins in A. thaliana are not direct and they are rather mediated by one of the Arabidopsis thaliana Telomere Repeat Binding (AtTRB) proteins. We further show that plant orthologue of dyskerin, named AtCBF5, is indirectly associated with AtTRB proteins but not with the AtRuvBL proteins in the plant nucleus/nucleolus, and interacts with the Protection of telomere 1 (AtPOT1a) in the nucleolus or cytoplasmic foci. Our genome-wide phylogenetic analyses identify orthologues in RuvBL protein family within the plant kingdom. Dysfunction of AtRuvBL genes in heterozygous T-DNA insertion A. thaliana mutants results in reduced telomerase activity and indicate the involvement of AtRuvBL in plant telomerase biogenesis.
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Affiliation(s)
- Šárka Schořová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno, Czech Republic
| | - Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
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16
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Crhák T, Zachová D, Fojtová M, Sýkorová E. The region upstream of the telomerase reverse transcriptase gene is essential for in planta telomerase complementation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:41-51. [PMID: 30824060 DOI: 10.1016/j.plantsci.2019.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/29/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
Telomerase is essential for the maintenance of telomeres, structures located at the ends of linear eukaryotic chromosomes that are crucial for genomic stability. Telomerase has been frequently explored in mammals because of its activity in many types of cancers, but knowledge in plants is rather sketchy despite plants representing useful models due to peculiarities in their telomeres and telomerase biology. We studied in planta complementation of telomerase in Arabidopsis thaliana mutant plants with disrupted expression of the gene encoding the telomerase protein subunit (AtTERT) and significantly shortened telomeres. We found that the upstream region of AtTERT, previously identified as a putative minimal promoter, was essential for reconstitution of telomerase function, as demonstrated by the full or partial recovery of the telomere phenotype in mutants. In contrast, transformation by the full length AtTERT gene construct resulted in more progressive telomere shortening in mutants and even in wild type plants, despite the high level of AtTERT transcript and telomerase activity detected by in vitro assay. Thus, the telomerase protein subunit putative promoter is essential for in planta telomerase reconstitution and restoration of its catalytical activity. Contributions from other factors, including those tissue-specific, for proper telomerase function are discussed.
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Affiliation(s)
- Tomáš Crhák
- The Czech Academy of Sciences, Institute of Biophysics, Brno, Czech Republic; Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Dagmar Zachová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Eva Sýkorová
- The Czech Academy of Sciences, Institute of Biophysics, Brno, Czech Republic.
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17
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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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Sováková PP, Magdolenová A, Konečná K, Rájecká V, Fajkus J, Fojtová M. Telomere elongation upon transfer to callus culture reflects the reprogramming of telomere stability control in Arabidopsis. PLANT MOLECULAR BIOLOGY 2018; 98:81-99. [PMID: 30128721 DOI: 10.1007/s11103-018-0765-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 08/12/2018] [Indexed: 05/23/2023]
Abstract
KEY MESSAGE Standard pathways involved in the regulation of telomere stability do not contribute to gradual telomere elongation observed in the course of A. thaliana calli propagation. Genetic and epigenetic changes accompanying the culturing of plant cells have frequently been reported. Here we aimed to characterize the telomere homeostasis during long term callus propagation. While in Arabidopsis thaliana calli gradual telomere elongation was observed, telomeres were stable in Nicotiana tabacum and N. sylvestris cultures. Telomere elongation during callus propagation is thus not a general feature of plant cells. The long telomere phenotype in Arabidopsis calli was correlated neither with changes in telomerase activity nor with activation of alternative mechanisms of telomere elongation. The dynamics of telomere length changes was maintained in mutant calli with loss of function of important epigenetic modifiers but compromised in the presence of epigenetically active drug zebularine. To examine whether the cell culture-induced disruption of telomere homeostasis is associated with the modulated structure of chromosome ends, epigenetic properties of telomere chromatin were analysed. Albeit distinct changes in epigenetic modifications of telomere histones were observed, these were broadly stochastic. Our results show that contrary to animal cells, the structure and function of plant telomeres is not determined significantly by the epigenetic character of telomere chromatin. Set of differentially transcribed genes was identified in calli, but considering the known telomere- or telomerase-related functions of respective proteins, none of these changes per se was apparently related to the elongated telomere phenotype. Based on our data, we propose that the disruption in telomere homeostasis in Arabidopsis calli arises from the interplay of multiple factors, as a part of reprogramming of plant cells to long-term culture conditions.
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Affiliation(s)
- Pavla Polanská Sováková
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic
| | - Alžbeta Magdolenová
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic
| | - Klára Konečná
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic
| | - Veronika Rájecká
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, 625 00, Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., 612 65, Brno, Czech Republic
| | - Miloslava Fojtová
- Laboratory of Functional Genomics and Proteomics, Faculty of Science, National Centre for Biomolecular Research, Masaryk University, 625 00, Brno, Czech Republic.
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, 625 00, Brno, Czech Republic.
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Dokládal L, Benková E, Honys D, Dupľáková N, Lee LY, Gelvin SB, Sýkorová E. An armadillo-domain protein participates in a telomerase interaction network. PLANT MOLECULAR BIOLOGY 2018; 97:407-420. [PMID: 29948659 DOI: 10.1007/s11103-018-0747-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Arabidopsis and human ARM protein interact with telomerase. Deregulated mRNA levels of DNA repair and ribosomal protein genes in an Arabidopsis arm mutant suggest non-telomeric ARM function. The human homolog ARMC6 interacts with hTRF2. Telomerase maintains telomeres and has proposed non-telomeric functions. We previously identified interaction of the C-terminal domain of Arabidopsis telomerase reverse transcriptase (AtTERT) with an armadillo/β-catenin-like repeat (ARM) containing protein. Here we explore protein-protein interactions of the ARM protein, AtTERT domains, POT1a, TRF-like family and SMH family proteins, and the chromatin remodeling protein CHR19 using bimolecular fluorescence complementation (BiFC), yeast two-hybrid (Y2H) analysis, and co-immunoprecipitation. The ARM protein interacts with both the N- and C-terminal domains of AtTERT in different cellular compartments. ARM interacts with CHR19 and TRF-like I family proteins that also bind AtTERT directly or through interaction with POT1a. The putative human ARM homolog co-precipitates telomerase activity and interacts with hTRF2 protein in vitro. Analysis of Arabidopsis arm mutants shows no obvious changes in telomere length or telomerase activity, suggesting that ARM is not essential for telomere maintenance. The observed interactions with telomerase and Myb-like domain proteins (TRF-like family I) may therefore reflect possible non-telomeric functions. Transcript levels of several DNA repair and ribosomal genes are affected in arm mutants, and ARM, likely in association with other proteins, suppressed expression of XRCC3 and RPSAA promoter constructs in luciferase reporter assays. In conclusion, ARM can participate in non-telomeric functions of telomerase, and can also perform its own telomerase-independent functions.
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Affiliation(s)
- Ladislav Dokládal
- Institute of Biophysics, The Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Biology, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Eva Benková
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - David Honys
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojova 263, 16502, Prague, Czech Republic
| | - Nikoleta Dupľáková
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojova 263, 16502, Prague, Czech Republic
| | - Lan-Ying Lee
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907-1392, USA
| | - Stanton B Gelvin
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907-1392, USA
| | - Eva Sýkorová
- Institute of Biophysics, The Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic.
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Xie X, Shippen DE. DDM1 guards against telomere truncation in Arabidopsis. PLANT CELL REPORTS 2018; 37:501-513. [PMID: 29392401 PMCID: PMC5880217 DOI: 10.1007/s00299-017-2245-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/26/2017] [Indexed: 05/20/2023]
Abstract
Prolonged hypomethylation of DNA leads to telomere truncation correlated with increased telomere recombination, transposon mobilization and stem cell death. Epigenetic pathways, including DNA methylation, are crucial for telomere maintenance. Deficient in DNA Methylation 1 (DDM1) encodes a nucleosome remodeling protein, required to maintain DNA methylation in Arabidopsis thaliana. Plants lacking DDM1 can be self-propagated, but in the sixth generation (G6) hypomethylation leads to rampant transposon activation and infertility. Here we examine the role of DDM1 in telomere length homeostasis through a longitudinal study of successive generations of ddm1-2 mutants. We report that bulk telomere length remains within the wild-type range for the first five generations (G1-G5), and then precipitously drops in G6. While telomerase activity becomes more variable in later generation ddm1-2 mutants, there is no correlation between enzyme activity and telomere length. Plants lacking DDM1 also exhibit no dysregulation of several known telomere-associated transcripts, including TERRA. Instead, telomere shortening coincides with increased G-overhangs and extra-chromosomal circles, consistent with deletional recombination. Telomere shortening also correlates with transcriptional activation of retrotransposons, and a hypersensitive DNA damage response in root apical meristems. Since abiotic stresses, including DNA damage, stimulate homologous recombination, we hypothesize that telomere deletion in G6 ddm1-2 mutants is a by-product of elevated genome-wide recombination in response to transposon mobilization. Further, we speculate that telomere truncation may be beneficial in adverse environmental conditions by accelerating the elimination of stem cells with aberrant genomes.
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Affiliation(s)
- Xiaoyuan Xie
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA.
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21
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Macovei A, Sahoo RK, Faè M, Balestrazzi A, Carbonera D, Tuteja N. Overexpression of PDH45 or SUV3 helicases in rice leads to delayed leaf senescence-associated events. PROTOPLASMA 2017; 254:1103-1113. [PMID: 27586643 DOI: 10.1007/s00709-016-1017-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Senescence is a very complex process characterized by a highly regulated series of degenerative events which include changes in cell structure, metabolism and gene expression. In animals, one of the indicators of senescence is telomere shortening. In plants, this aspect is more puzzling because telomere shortening is not always correlated with senescence. In some cases, there were no differences in telomere length during plant developmental stages while in other cases both shortening and lengthening have been observed. Several genes involved in telomere homeostasis have been identified in plants, including some helicases. In the present study, the salinity stress-tolerant transgenic IR64 rice plants overexpressing the PDH45 (Pea DNA Helicase 45) or SUV3 (Suppressor of Var1-3) genes were used to test their performance during natural senescence at flowering (S2) and seed maturation (S4) developmental stages. Our results reveal that both PDH45 and SUV3 transgenic rice lines present decreased levels of necrosis/apoptosis as compared to wild type plants. Additionally, in these plants, some senescence-associated genes (SAGs) were downregulated at S2 and S4 stages, while genes involved in the maintenance of genome stability and DNA repair were upregulated. More interestingly, the telomeres were up to 3.8-fold longer in the SUV3 overexpressing lines as compared to wild type plants. This was associated with an increase (2.5-fold) in telomerase (OsTERT) transcript level. This is an interesting result reporting a possible involvement of SUV3 in telomere homeostasis in plants.
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Affiliation(s)
- Anca Macovei
- Plant Molecular Biology Group, International Center for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, 110067, New Delhi, India
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Ferrata 9, 27100, Pavia, Italy
| | - Ranjan K Sahoo
- Plant Molecular Biology Group, International Center for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, 110067, New Delhi, India
| | - Matteo Faè
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Ferrata 9, 27100, Pavia, Italy
| | - Alma Balestrazzi
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Ferrata 9, 27100, Pavia, Italy
| | - Daniela Carbonera
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Ferrata 9, 27100, Pavia, Italy
| | - Narendra Tuteja
- Plant Molecular Biology Group, International Center for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, 110067, New Delhi, India.
- Amity Institute of Microbial Technology, Amity University Uttar Pradesh, E2-Block, Sector 125, Noida, UP, 201313, India.
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22
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Jurečková JF, Sýkorová E, Hafidh S, Honys D, Fajkus J, Fojtová M. Tissue-specific expression of telomerase reverse transcriptase gene variants in Nicotiana tabacum. PLANTA 2017; 245:549-561. [PMID: 27900472 DOI: 10.1007/s00425-016-2624-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
MAIN CONCLUSION In tobacco, three sequence variants of the TERT gene have been described. We revealed unbalanced levels of TERT variant transcripts in vegetative tobacco tissues and enhanced TERT transcription and telomerase activity in reproductive tissues. Telomerase is a ribonucleoprotein complex responsible for the maintenance of telomeres, structures delimiting ends of linear eukaryotic chromosomes. In the Nicotiana tabacum (tobacco) allotetraploid plant, three sequence variants (paralogs) of the gene coding for the telomerase reverse transcriptase subunit (TERT) have been described, two of them derived from the maternal N. sylvestris genome (TERT_Cs, TERT_D) and one originated from the N. tomentosiformis paternal genome (TERT_Ct). In this work, we analyzed the transcription of TERT variants in correlation with telomerase activity in tobacco tissues. High and approximately comparable levels of TERT_Ct and TERT_Cs transcripts were detected in seedlings, roots, flower buds and leaves, while the transcript of the TERT_D variant was markedly underrepresented. Similarly, in N. sylvestris tissues, TERT_Cs transcript significantly predominated. A specific pattern of TERT transcripts was found in samples of tobacco pollen with the TERT_Cs variant clearly dominating particularly at the early stage of pollen development. Detailed analysis of TERT_C variants representation in functionally distinct fractions of pollen transcriptome revealed their prevalence in large ribonucleoprotein particles encompassing translationally silent mRNA; only a minority of TERT_Ct and TERT_Cs transcripts were localized in actively translated polysomes. Histones of the TERT_C chromatin were decorated predominantly with the euchromatin-specific epigenetic modification in both telomerase-positive and telomerase-negative tobacco tissues. We conclude that the existence and transcription pattern of tobacco TERT paralogs represents an interesting phenomenon and our results indicate its functional significance. Nicotiana species have again proved to be appropriate and useful model plants in telomere biology studies.
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Affiliation(s)
- Jana Fišerová Jurečková
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Said Hafidh
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic v.v.i., Rozvojová 263, 165 02, Prague, Czech Republic
| | - David Honys
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic v.v.i., Rozvojová 263, 165 02, Prague, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
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23
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Uzlíková M, Fulnečková J, Weisz F, Sýkorová E, Nohýnková E, Tůmová P. Characterization of telomeres and telomerase from the single-celled eukaryote Giardia intestinalis. Mol Biochem Parasitol 2017; 211:31-38. [DOI: 10.1016/j.molbiopara.2016.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/08/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
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24
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Arora A, Beilstein MA, Shippen DE. Evolution of Arabidopsis protection of telomeres 1 alters nucleic acid recognition and telomerase regulation. Nucleic Acids Res 2016; 44:9821-9830. [PMID: 27651456 PMCID: PMC5175356 DOI: 10.1093/nar/gkw807] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 09/01/2016] [Accepted: 09/03/2016] [Indexed: 11/14/2022] Open
Abstract
Protection of telomeres (POT1) binds chromosome ends, recognizing single-strand telomeric DNA via two oligonucleotide/oligosaccharide binding folds (OB-folds). The Arabidopsis thaliana POT1a and POT1b paralogs are atypical: they do not exhibit telomeric DNA binding, and they have opposing roles in regulating telomerase activity. AtPOT1a stimulates repeat addition processivity of the canonical telomerase enzyme, while AtPOT1b interacts with a regulatory lncRNA that represses telomerase activity. Here, we show that OB1 of POT1a, but not POT1b, has an intrinsic affinity for telomeric DNA. DNA binding was dependent upon a highly conserved Phe residue (F65) that in human POT1 directly contacts telomeric DNA. F65A mutation of POT1aOB1 abolished DNA binding and diminished telomerase repeat addition processivity. Conversely, AtPOT1b and other POT1b homologs from Brassicaceae and its sister family, Cleomaceae, naturally bear a non-aromatic amino acid at this position. By swapping Val (V63) with Phe, AtPOT1bOB1 gained the capacity to bind telomeric DNA and to stimulate telomerase repeat addition processivity. We conclude that, in the context of DNA binding, variation at a single amino acid position promotes divergence of the AtPOT1b paralog from the ancestral POT1 protein.
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Affiliation(s)
- Amit Arora
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843, USA
| | - Mark A Beilstein
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843, USA
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25
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Santos-Serejo JA, Aguiar-Perecin MLR. Breakage-fusion-bridge cycles and de novo telomere formation on broken chromosomes in maize callus cultures. Genome 2016; 59:367-78. [PMID: 27203556 DOI: 10.1139/gen-2015-0211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Breakpoints involved in chromosome alterations associated with heterochromatin have been detected in maize plants regenerated from callus culture. A cytogenetic analysis of plants regenerated from a maize callus was performed aiming to analyze the stability of a chromosome 7 bearing a deficiency-duplication (Df-Dp), which was interpreted as derived from a chromatid type breakage-fusion-bridge (BFB) cycle. The Df-Dp chromosome 7 was stable in mitotic and meiotic cells of the regenerated plants. Fluorescence in situ hybridization showed signals of telomeric sequences on the broken chromosome arm and provided evidence of de novo telomere formation. The stability of two types of altered chromosome 7 was investigated in C-banded metaphases from samples of the original callus that were collected during a period of 30-42 months after culture initiation. New alterations involving heterochromatic knobs of chromosomes 7 and 9 were observed. The aberrant chromosomes were stable in the subcultures, thus providing evidence of broken chromosome healing. The examination of anaphases showed the presence of bridges, which was consistent with the occurrence of BFB cycles. De novo telomere formation occurred in euchromatic and heterochromatic chromosome termini. The results point to events of chromosomal evolution that might occur in plants.
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Affiliation(s)
- Janay A Santos-Serejo
- Department of Genetics, Luiz de Queiroz Agriculture College, University of São Paulo, 13418-900 Piracicaba, SP, Brazil.,Department of Genetics, Luiz de Queiroz Agriculture College, University of São Paulo, 13418-900 Piracicaba, SP, Brazil
| | - Margarida L R Aguiar-Perecin
- Department of Genetics, Luiz de Queiroz Agriculture College, University of São Paulo, 13418-900 Piracicaba, SP, Brazil.,Department of Genetics, Luiz de Queiroz Agriculture College, University of São Paulo, 13418-900 Piracicaba, SP, Brazil
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26
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Fajkus P, Peška V, Sitová Z, Fulnečková J, Dvořáčková M, Gogela R, Sýkorová E, Hapala J, Fajkus J. Allium telomeres unmasked: the unusual telomeric sequence (CTCGGTTATGGG)n is synthesized by telomerase. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:337-47. [PMID: 26716914 DOI: 10.1111/tpj.13115] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 05/25/2023]
Abstract
Phylogenetic divergence in Asparagales plants is associated with switches in telomere sequences. The last switch occurred with divergence of the genus Allium (Amaryllidaceae) from the other Allioideae (formerly Alliaceae) genera, resulting in uncharacterized telomeres maintained by an unknown mechanism. To characterize the unknown Allium telomeres, we applied a combination of bioinformatic processing of transcriptomic and genomic data with standard approaches in telomere biology such as BAL31 sensitivity tests, terminal restriction fragment analysis, the telomere repeat amplification protocol (TRAP), and fluorescence in situ hybridization (FISH). Using these methods, we characterize the unusual telomeric sequence (CTCGGTTATGGG)n present in Allium species, demonstrate its synthesis by telomerase, and characterize the telomerase reverse transcriptase (TERT) subunit of Allium cepa. Our findings open up the possibility of studying the molecular details of the evolutionary genetic change in Allium telomeres and its possible role in speciation. Experimental studies addressing the implications of this change in terms of the interplay of telomere components may now be designed to shed more light on telomere functions and evolution in general.
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Affiliation(s)
- 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
| | - Vratislav Peška
- 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
| | - Jana Fulnečková
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265, Brno, Czech Republic
| | - Martina Dvořáčková
- 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
| | - Roman Gogela
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265, Brno, Czech Republic
| | - Jan Hapala
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, 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
- 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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27
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Tran TD, Cao HX, Jovtchev G, Neumann P, Novák P, Fojtová M, Vu GTH, Macas J, Fajkus J, Schubert I, Fuchs J. Centromere and telomere sequence alterations reflect the rapid genome evolution within the carnivorous plant genus Genlisea. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:1087-99. [PMID: 26485466 DOI: 10.1111/tpj.13058] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 10/07/2015] [Accepted: 10/15/2015] [Indexed: 05/25/2023]
Abstract
Linear chromosomes of eukaryotic organisms invariably possess centromeres and telomeres to ensure proper chromosome segregation during nuclear divisions and to protect the chromosome ends from deterioration and fusion, respectively. While centromeric sequences may differ between species, with arrays of tandemly repeated sequences and retrotransposons being the most abundant sequence types in plant centromeres, telomeric sequences are usually highly conserved among plants and other organisms. The genome size of the carnivorous genus Genlisea (Lentibulariaceae) is highly variable. Here we study evolutionary sequence plasticity of these chromosomal domains at an intrageneric level. We show that Genlisea nigrocaulis (1C = 86 Mbp; 2n = 40) and G. hispidula (1C = 1550 Mbp; 2n = 40) differ as to their DNA composition at centromeres and telomeres. G. nigrocaulis and its close relative G. pygmaea revealed mainly 161 bp tandem repeats, while G. hispidula and its close relative G. subglabra displayed a combination of four retroelements at centromeric positions. G. nigrocaulis and G. pygmaea chromosome ends are characterized by the Arabidopsis-type telomeric repeats (TTTAGGG); G. hispidula and G. subglabra instead revealed two intermingled sequence variants (TTCAGG and TTTCAGG). These differences in centromeric and, surprisingly, also in telomeric DNA sequences, uncovered between groups with on average a > 9-fold genome size difference, emphasize the fast genome evolution within this genus. Such intrageneric evolutionary alteration of telomeric repeats with cytosine in the guanine-rich strand, not yet known for plants, might impact the epigenetic telomere chromatin modification.
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Affiliation(s)
- Trung D Tran
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
| | - Hieu X Cao
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
| | - Gabriele Jovtchev
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
| | - Pavel Neumann
- Biology Centre of the Academy of Sciences of the Czech Republic, Institute of Plant Molecular Biology, Branišovská 31/1160, 37005, České Budějovice, Czech Republic
| | - Petr Novák
- Biology Centre of the Academy of Sciences of the Czech Republic, Institute of Plant Molecular Biology, Branišovská 31/1160, 37005, České Budějovice, Czech Republic
| | - Miloslava Fojtová
- Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Giang T H Vu
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
| | - Jiří Macas
- Biology Centre of the Academy of Sciences of the Czech Republic, Institute of Plant Molecular Biology, Branišovská 31/1160, 37005, České Budějovice, Czech Republic
| | - Jiří Fajkus
- Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 61265, Brno, Czech Republic
| | - Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
- Central European Institute of Technology (CEITEC) and Faculty of Science, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Joerg Fuchs
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, D-06466, Stadt Seeland, Germany
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28
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Fulnečková J, Ševčíková T, Lukešová A, Sýkorová E. Transitions between the Arabidopsis-type and the human-type telomere sequence in green algae (clade Caudivolvoxa, Chlamydomonadales). Chromosoma 2015; 125:437-51. [PMID: 26596989 DOI: 10.1007/s00412-015-0557-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/04/2015] [Accepted: 11/09/2015] [Indexed: 11/25/2022]
Abstract
Telomeres are nucleoprotein structures that distinguish native chromosomal ends from double-stranded breaks. They are maintained by telomerase that adds short G-rich telomeric repeats at chromosomal ends in most eukaryotes and determines the TnAmGo sequence of canonical telomeres. We employed an experimental approach that was based on detection of repeats added by telomerase to identify the telomere sequence type forming the very ends of chromosomes. Our previous studies that focused on the algal order Chlamydomonadales revealed several changes in telomere motifs that were consistent with the phylogeny and supported the concept of the Arabidopsis-type sequence being the ancestral telomeric motif for green algae. In addition to previously described independent transitions to the Chlamydomonas-type sequence, we report that the ancestral telomeric motif was replaced by the human-type sequence in the majority of algal species grouped within a higher order clade, Caudivolvoxa. The Arabidopsis-type sequence was apparently retained in the Polytominia clade. Regarding the telomere sequence, the Chlorogonia clade within Caudivolvoxa bifurcates into two groups, one with the human-type sequence and the other group with the Arabidopsis-type sequence that is solely formed by the Chlorogonium species. This suggests that reversion to the Arabidopsis-type telomeric motif occurred in the common ancestral Chlorogonium species. The human-type sequence is also synthesized by telomerases of algal strains from Arenicolinia, Dunaliellinia and Stephanosphaerinia, except a distinct subclade within Stephanosphaerinia, where telomerase activity was not detected and a change to an unidentified telomeric motif might arise. We discuss plausible reasons why changes in telomeric motifs were tolerated during evolution of green algae.
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Affiliation(s)
- Jana Fulnečková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic.,Faculty of Science, and CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Tereza Ševčíková
- Department of Biology and Ecology, Life Science Research Centre & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Chittussiho 10, CZ-71000, Ostrava, Czech Republic
| | - Alena Lukešová
- Institute of Soil Biology, Biology Centre Academy of Sciences of the Czech Republic, v.vi., Na Sádkách 7, CZ-37005, České Budějovice, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic. .,Faculty of Science, and CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic.
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29
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Dokládal L, Honys D, Rana R, Lee LY, Gelvin SB, Sýkorová E. cDNA Library Screening Identifies Protein Interactors Potentially Involved in Non-Telomeric Roles of Arabidopsis Telomerase. FRONTIERS IN PLANT SCIENCE 2015; 6:985. [PMID: 26617625 PMCID: PMC4641898 DOI: 10.3389/fpls.2015.00985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/27/2015] [Indexed: 05/27/2023]
Abstract
Telomerase-reverse transcriptase (TERT) plays an essential catalytic role in maintaining telomeres. However, in animal systems telomerase plays additional non-telomeric functional roles. We previously screened an Arabidopsis cDNA library for proteins that interact with the C-terminal extension (CTE) TERT domain and identified a nuclear-localized protein that contains an RNA recognition motif (RRM). This RRM-protein forms homodimers in both plants and yeast. Mutation of the gene encoding the RRM-protein had no detectable effect on plant growth and development, nor did it affect telomerase activity or telomere length in vivo, suggesting a non-telomeric role for TERT/RRM-protein complexes. The gene encoding the RRM-protein is highly expressed in leaf and reproductive tissues. We further screened an Arabidopsis cDNA library for proteins that interact with the RRM-protein and identified five interactors. These proteins are involved in numerous non-telomere-associated cellular activities. In plants, the RRM-protein, both alone and in a complex with its interactors, localizes to nuclear speckles. Transcriptional analyses in wild-type and rrm mutant plants, as well as transcriptional co-analyses, suggest that TERT, the RRM-protein, and the RRM-protein interactors may play important roles in non-telomeric cellular functions.
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Affiliation(s)
- Ladislav Dokládal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology and Faculty of Science, Masaryk UniversityBrno, Czech Republic
- Institute of Biophysics – Academy of Sciences of the Czech Republic v.v.i.Brno, Czech Republic
| | - David Honys
- Institute of Experimental Botany – Academy of Sciences of the Czech Republic v.v.i.Prague, Czech Republic
| | - Rajiv Rana
- Institute of Experimental Botany – Academy of Sciences of the Czech Republic v.v.i.Prague, Czech Republic
| | - Lan-Ying Lee
- Department of Biological Sciences, Purdue University, West LafayetteIN, USA
| | - Stanton B. Gelvin
- Department of Biological Sciences, Purdue University, West LafayetteIN, USA
| | - Eva Sýkorová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology and Faculty of Science, Masaryk UniversityBrno, Czech Republic
- Institute of Biophysics – Academy of Sciences of the Czech Republic v.v.i.Brno, Czech Republic
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31
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Impaired telomerase activity hinders proliferation and in vitro transformation of Penaeus monodon lymphoid cells. Cytotechnology 2015; 68:1301-14. [PMID: 26084784 DOI: 10.1007/s10616-015-9890-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/19/2015] [Indexed: 12/16/2022] Open
Abstract
Retaining terminal transferase activity of telomerase, the ribonucleoprotein enzyme which add telomeric repeats on chromosome end is thought to be required to prevent cellular ageing. Additionally, telomerase considered as a marker for cell proliferation and immortalization in eukaryotes. We examined telomerase activity in tissues and lymphoid cell culture of Penaeus monodon. Along with telomerase activity, telomere repeats and an attempt on identification of telomerase reverse transcriptase (PmTERT) were made. Telomeric repeat amplification protocol revealed that telomerase-dependent telomeric lengthening has been taking place in P. monodon and the adult tissues were retaining this capacity throughout their lifespan with the highest activity in ovary, testis and lymphoid organ. However, telomerase activity could not be detected in lymphoid cells in culture. The canonical telomeric repeats added by telomerase of lymphoid tissue extract were identified as TTAGG, but pentameric repeats GGTTA and AGGTT were also added by the telomerase. PmTERT protein sequence (partial) shared 100 % identity with the TERT sequence of Daphnia pulex, 27 % sequence identity with Purple sea urchin and 24-25 % with Zebra fish. Undetectable telomerase activity in lymphoid cell culture supports the hypothesis that the inadequate telomerase activity or gene expression may be a reason that prevents neoplastic transformation and spontaneous immortalization of the cells in vitro. Thus, it is envisaged that telomerase activation in lymphoid cells may surmount cellular ageing for in vitro transformation and cell line establishment.
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Jankowska M, Fuchs J, Klocke E, Fojtová M, Polanská P, Fajkus J, Schubert V, Houben A. Holokinetic centromeres and efficient telomere healing enable rapid karyotype evolution. Chromosoma 2015; 124:519-28. [PMID: 26062516 DOI: 10.1007/s00412-015-0524-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 05/21/2015] [Accepted: 05/22/2015] [Indexed: 11/24/2022]
Abstract
Species with holocentric chromosomes are often characterized by a rapid karyotype evolution. In contrast to species with monocentric chromosomes where acentric fragments are lost during cell division, breakage of holocentric chromosomes creates fragments with normal centromere activity. To decipher the mechanism that allows holocentric species an accelerated karyotype evolution via chromosome breakage, we analyzed the chromosome complements of irradiated Luzula elegans plants. The resulting chromosomal fragments and rearranged chromosomes revealed holocentromere-typical CENH3 and histone H2AThr120ph signals as well as the same mitotic mobility like unfragmented chromosomes. Newly synthesized telomeres at break points become detectable 3 weeks after irradiation. The presence of active telomerase suggests a telomerase-based mechanism of chromosome healing. A successful transmission of holocentric chromosome fragments across different generations was found for most offspring of irradiated plants. Hence, a combination of holokinetic centromere activity and the fast formation of new telomeres at break points enables holocentric species a rapid karyotype evolution involving chromosome fissions and rearrangements.
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Affiliation(s)
- Maja Jankowska
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Correnstrasse 3, D-06466, Stadt Seeland, Germany
| | - Jörg Fuchs
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Correnstrasse 3, D-06466, Stadt Seeland, Germany
| | - Evelyn Klocke
- Julius Kühn-Institute, Institute for Breeding Research on Horticultural Crops, Erwin-Baur-Straße 27, D-06484, Quedlinburg, Germany
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic
| | - Pavla Polanská
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic.,Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00, Brno, Czech Republic
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Correnstrasse 3, D-06466, Stadt Seeland, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Correnstrasse 3, D-06466, Stadt Seeland, Germany.
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Peška V, Fajkus P, Fojtová M, Dvořáčková M, Hapala J, Dvořáček V, Polanská P, Leitch AR, Sýkorová E, Fajkus J. Characterisation of an unusual telomere motif (TTTTTTAGGG)n in the plant Cestrum elegans (Solanaceae), a species with a large genome. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:644-54. [PMID: 25828846 DOI: 10.1111/tpj.12839] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/20/2015] [Accepted: 03/23/2015] [Indexed: 05/26/2023]
Abstract
The characterization of unusual telomere sequence sheds light on patterns of telomere evolution, maintenance and function. Plant species from the closely related genera Cestrum, Vestia and Sessea (family Solanaceae) lack known plant telomeric sequences. Here we characterize the telomere of Cestrum elegans, work that was a challenge because of its large genome size and few chromosomes (1C 9.76 pg; n = 8). We developed an approach that combines BAL31 digestion, which digests DNA from the ends and chromosome breaks, with next-generation sequencing (NGS), to generate data analysed in RepeatExplorer, designed for de novo repeats identification and quantification. We identify an unique repeat motif (TTTTTTAGGG)n in C. elegans, occurring in ca. 30 400 copies per haploid genome, averaging ca. 1900 copies per telomere, and synthesized by telomerase. We demonstrate that the motif is synthesized by telomerase. The occurrence of an unusual eukaryote (TTTTTTAGGG)n telomeric motif in C. elegans represents a switch in motif from the 'typical' angiosperm telomere (TTTAGGG)n . That switch may have happened with the divergence of Cestrum, Sessea and Vestia. The shift in motif when it arose would have had profound effects on telomere activity. Thus our finding provides a unique handle to study how telomerase and telomeres responded to genetic change, studies that will shed more light on telomere function.
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Affiliation(s)
- Vratislav Peška
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Petr Fajkus
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Miloslava Fojtová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Martina Dvořáčková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Jan Hapala
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Vojtěch Dvořáček
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
| | - Pavla Polanská
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Eva Sýkorová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Jiří Fajkus
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Faculty of Science, and CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
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González-García MP, Pavelescu I, Canela A, Sevillano X, Leehy KA, Nelson ADL, Ibañes M, Shippen DE, Blasco MA, Caño-Delgado AI. Single-cell telomere-length quantification couples telomere length to meristem activity and stem cell development in Arabidopsis. Cell Rep 2015; 11:977-989. [PMID: 25937286 PMCID: PMC4827700 DOI: 10.1016/j.celrep.2015.04.013] [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: 08/15/2014] [Revised: 02/19/2015] [Accepted: 04/05/2015] [Indexed: 01/14/2023] Open
Abstract
Telomeres are specialized nucleoprotein caps that protect chromosome ends assuring cell division. Single-cell telomere quantification in animals established a critical role for telomerase in stem cells, yet, in plants, telomere-length quantification has been reported only at the organ level. Here, a quantitative analysis of telomere length of single cells in Arabidopsis root apex uncovered a heterogeneous telomere-length distribution of different cell lineages showing the longest telomeres at the stem cells. The defects in meristem and stem cell renewal observed in tert mutants demonstrate that telomere lengthening by TERT sets a replicative limit in the root meristem. Conversely, the long telomeres of the columella cells and the premature stem cell differentiation plt1,2 mutants suggest that differentiation can prevent telomere erosion. Overall, our results indicate that telomere dynamics are coupled to meristem activity and continuous growth, disclosing a critical association between telomere length, stem cell function, and the extended lifespan of plants.
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Affiliation(s)
- Mary-Paz González-García
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona 08193, Spain; Centro Nacional de Biotecnología (CSIC), Cantoblanco, 28049 Madrid, Spain
| | - Irina Pavelescu
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona 08193, Spain; Department of Structure and Constituents of Matter, Faculty of Physics, University of Barcelona, Barcelona 08024, Spain
| | - Andrés Canela
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Xavier Sevillano
- Grup de Recerca en Tecnologies Mèdia, La Salle - Universitat Ramon Llull, Barcelona 08022, Spain
| | - Katherine A Leehy
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Andrew D L Nelson
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Marta Ibañes
- Department of Structure and Constituents of Matter, Faculty of Physics, University of Barcelona, Barcelona 08024, Spain
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Ana I Caño-Delgado
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona 08193, Spain.
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Fojtová M, Sýkorová E, Najdekrová L, Polanská P, Zachová D, Vagnerová R, Angelis KJ, Fajkus J. Telomere dynamics in the lower plant Physcomitrella patens. PLANT MOLECULAR BIOLOGY 2015; 87:591-601. [PMID: 25701469 DOI: 10.1007/s11103-015-0299-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/16/2015] [Indexed: 06/04/2023]
Abstract
A comparative approach in biology is needed to assess the universality of rules governing this discipline. In plant telomere research, most of the key principles were established based on studies in only single model plant, Arabidopsis thaliana. These principles include the absence of telomere shortening during plant development and the corresponding activity of telomerase in dividing (meristem) plant cells. Here we examine these principles in Physcomitrella patens as a representative of lower plants. To follow telomerase expression, we first characterize the gene coding for the telomerase reverse transcriptase subunit PpTERT in P. patens, for which only incomplete prediction has been available so far. In protonema cultures of P. patens, growing by filament apical cell division, the proportion of apical (dividing) cells was quantified and telomere length, telomerase expression and activity were determined. Our results show telomere stability and demonstrate proportionality of telomerase activity and expression with the number of apical cells. In addition, we analyze telomere maintenance in mre11, rad50, nbs1, ku70 and lig4 mutants of P. patens and compare the impact of these mutations in double-strand-break (DSB) repair pathways with earlier observations in corresponding A. thaliana mutants. Telomere phenotypes are absent and DSB repair kinetics is not affected in P. patens mutants for DSB factors involved in non-homologous end joining (NHEJ). This is compliant with the overall dominance of homologous recombination over NHEJ pathways in the moss, contrary to the inverse situation in flowering plants.
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Affiliation(s)
- Miloslava Fojtová
- Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
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Analysis of the age of Panax ginseng based on telomere length and telomerase activity. Sci Rep 2015; 5:7985. [PMID: 25614145 PMCID: PMC5379010 DOI: 10.1038/srep07985] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/24/2014] [Indexed: 11/17/2022] Open
Abstract
Ginseng, which is the root of Panax ginseng (Araliaceae), has been used in Oriental medicine as a stimulant and dietary supplement for more than 7,000 years. Older ginseng plants are substantially more medically potent, but ginseng age can be simulated using unscrupulous cultivation practices. Telomeres progressively shorten with each cell division until they reach a critical length, at which point cells enter replicative senescence. However, in some cells, telomerase maintains telomere length. In this study, to determine whether telomere length reflects ginseng age and which tissue is best for such an analysis, we examined telomerase activity in the main roots, leaves, stems, secondary roots and seeds of ginseng plants of known age. Telomere length in the main root (approximately 1 cm below the rhizome) was found to be the best indicator of age. Telomeric terminal restriction fragment (TRF) lengths, which are indicators of telomere length, were determined for the main roots of plants of different ages through Southern hybridization analysis. Telomere length was shown to be positively correlated with plant age, and a simple mathematical model was formulated to describe the relationship between telomere length and age for P. ginseng.
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Renfrew KB, Song X, Lee JR, Arora A, Shippen DE. POT1a and components of CST engage telomerase and regulate its activity in Arabidopsis. PLoS Genet 2014; 10:e1004738. [PMID: 25329641 PMCID: PMC4199523 DOI: 10.1371/journal.pgen.1004738] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/06/2014] [Indexed: 11/18/2022] Open
Abstract
Protection of Telomeres 1 (POT1) is a conserved nucleic acid binding protein implicated in both telomere replication and chromosome end protection. We previously showed that Arabidopsis thaliana POT1a associates with the TER1 telomerase RNP, and is required for telomere length maintenance in vivo. Here we further dissect the function of POT1a and explore its interplay with the CST (CTC1/STN1/TEN1) telomere complex. Analysis of pot1a null mutants revealed that POT1a is not required for telomerase recruitment to telomeres, but is required for telomerase to maintain telomere tracts. We show that POT1a stimulates the synthesis of long telomere repeat arrays by telomerase, likely by enhancing repeat addition processivity. We demonstrate that POT1a binds STN1 and CTC1 in vitro, and further STN1 and CTC1, like POT1a, associate with enzymatically active telomerase in vivo. Unexpectedly, the in vitro interaction of STN1 with TEN1 and POT1a was mutually exclusive, indicating that POT1a and TEN1 may compete for the same binding site on STN1 in vivo. Finally, unlike CTC1 and STN1, TEN1 was not associated with active telomerase in vivo, consistent with our previous data showing that TEN1 negatively regulates telomerase enzyme activity. Altogether, our data support a two-state model in which POT1a promotes an extendable telomere state via contacts with the telomerase RNP as well as STN1 and CTC1, while TEN1 opposes these functions.
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Affiliation(s)
- Kyle B. Renfrew
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Xiangyu Song
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Jung Ro Lee
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Amit Arora
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Dorothy E. Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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Jaiswal A, Lakshmi P. Molecular inhibition of telomerase recruitment using designer peptides: anin silicoapproach. J Biomol Struct Dyn 2014; 33:1442-59. [DOI: 10.1080/07391102.2014.953207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Procházková Schrumpfová P, Vychodilová I, Dvořáčková M, Majerská J, Dokládal L, Schořová Š, Fajkus J. Telomere repeat binding proteins are functional components of Arabidopsis telomeres and interact with telomerase. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:770-81. [PMID: 24397874 PMCID: PMC4282523 DOI: 10.1111/tpj.12428] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/06/2013] [Accepted: 12/23/2013] [Indexed: 05/19/2023]
Abstract
Although telomere-binding proteins constitute an essential part of telomeres, in vivo data indicating the existence of a structure similar to mammalian shelterin complex in plants are limited. Partial characterization of a number of candidate proteins has not identified true components of plant shelterin or elucidated their functional mechanisms. Telomere repeat binding (TRB) proteins from Arabidopsis thaliana bind plant telomeric repeats through a Myb domain of the telobox type in vitro, and have been shown to interact with POT1b (Protection of telomeres 1). Here we demonstrate co-localization of TRB1 protein with telomeres in situ using fluorescence microscopy, as well as in vivo interaction using chromatin immunoprecipitation. Classification of the TRB1 protein as a component of plant telomeres is further confirmed by the observation of shortening of telomeres in knockout mutants of the trb1 gene. Moreover, TRB proteins physically interact with plant telomerase catalytic subunits. These findings integrate TRB proteins into the telomeric interactome of A. thaliana.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- *For correspondence (e-mails or )
| | - Ivona Vychodilová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
| | - Jana Majerská
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- †Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de LausanneStation 19, 1015, Lausanne, Switzerland
| | - Ladislav Dokládal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
| | - Šárka Schořová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
- *For correspondence (e-mails or )
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Ogrocká A, Polanská P, Majerová E, Janeba Z, Fajkus J, Fojtová M. Compromised telomere maintenance in hypomethylated Arabidopsis thaliana plants. Nucleic Acids Res 2013; 42:2919-31. [PMID: 24334955 PMCID: PMC3950684 DOI: 10.1093/nar/gkt1285] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Telomeres, nucleoprotein structures at the ends of linear eukaryotic chromosomes, are important for the maintenance of genomic stability. Telomeres were considered as typical heterochromatic regions, but in light of recent results, this view should be reconsidered. Asymmetrically located cytosines in plant telomeric DNA repeats may be substrates for a DNA methyltransferase enzyme and indeed, it was shown that these repeats are methylated. Here, we analyse the methylation of telomeric cytosines and the length of telomeres in Arabidopsis thaliana methylation mutants (met 1-3 and ddm 1-8), and in their wild-type siblings that were germinated in the presence of hypomethylation drugs. Our results show that cytosine methylation in telomeric repeats depends on the activity of MET1 and DDM1 enzymes. Significantly shortened telomeres occur in later generations of methylation mutants as well as in plants germinated in the presence of hypomethylation drugs, and this phenotype is stably transmitted to the next plant generation. A possible role of compromised in vivo telomerase action in the observed telomere shortening is hypothesized based on telomere analysis of hypomethylated telomerase knockout plants. Results are discussed in connection with previous data in this field obtained using different model systems.
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Affiliation(s)
- Anna Ogrocká
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 62500 Brno, Czech Republic, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Flemingovo nám. 2, 166 10, Prague, Czech Republic and Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
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Fulnecková J, Sevcíková T, Fajkus J, Lukesová A, Lukes M, Vlcek C, Lang BF, Kim E, Eliás M, Sykorová E. A broad phylogenetic survey unveils the diversity and evolution of telomeres in eukaryotes. Genome Biol Evol 2013; 5:468-83. [PMID: 23395982 PMCID: PMC3622300 DOI: 10.1093/gbe/evt019] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Telomeres, ubiquitous and essential structures of eukaryotic chromosomes, are known to come in a variety of forms, but knowledge about their actual diversity and evolution across the whole phylogenetic breadth of the eukaryotic life remains fragmentary. To fill this gap, we employed a complex experimental approach to probe telomeric minisatellites in various phylogenetically diverse groups of algae. Our most remarkable results include the following findings: 1) algae of the streptophyte class Klebsormidiophyceae possess the Chlamydomonas-type telomeric repeat (TTTTAGGG) or, in at least one species, a novel TTTTAGG repeat, indicating an evolutionary transition from the Arabidopsis-type repeat (TTTAGGG) ancestral for Chloroplastida; 2) the Arabidopsis-type repeat is also present in telomeres of Xanthophyceae, in contrast to the presence of the human-type repeat (TTAGGG) in other ochrophytes studied, and of the photosynthetic alveolate Chromera velia, consistent with its phylogenetic position close to apicomplexans and dinoflagellates; 3) glaucophytes and haptophytes exhibit the human-type repeat in their telomeres; and 4) ulvophytes and rhodophytes have unusual telomere structures recalcitrant to standard analysis. To obtain additional details on the distribution of different telomere types in eukaryotes, we performed in silico analyses of genomic data from major eukaryotic lineages, utilizing also genome assemblies from our on-going genome projects for representatives of three hitherto unsampled lineages (jakobids, malawimonads, and goniomonads). These analyses confirm the human-type repeat as the most common and possibly ancestral in eukaryotes, but alternative motifs replaced it along the phylogeny of diverse eukaryotic lineages, some of them several times independently.
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Affiliation(s)
- Jana Fulnecková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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Lee YW, Kim WT. Telomerase-dependent 3' G-strand overhang maintenance facilitates GTBP1-mediated telomere protection from misplaced homologous recombination. THE PLANT CELL 2013; 25:1329-42. [PMID: 23572544 PMCID: PMC3663271 DOI: 10.1105/tpc.112.107573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/17/2013] [Accepted: 03/26/2013] [Indexed: 05/09/2023]
Abstract
At the 3'-end of telomeres, single-stranded G-overhang telomeric repeats form a stable T-loop. Many studies have focused on the mechanisms that generate and regulate the length of telomere 3' G-strand overhangs, but the roles of G-strand overhang length control in proper T-loop formation and end protection remain unclear. Here, we examined functional relationships between the single-stranded telomere binding protein GTBP1 and G-strand overhang lengths maintained by telomerase in tobacco (Nicotiana tabacum). In tobacco plants, telomerase reverse transcriptase subunit (TERT) repression severely worsened the GTBP1 knockdown phenotypes, which were formally characterized as an outcome of telomere destabilization. TERT downregulation shortened the telomere 3' G-overhangs and increased telomere recombinational aberrations in GTBP1-suppressed plants. Correlatively, GTBP1-mediated inhibition of single-strand invasion into the double-strand telomeric sequences was impaired due to shorter single-stranded telomeres. Moreover, TERT/GTBP1 double knockdown amplified misplaced homologous recombination of G-strand overhangs into intertelomeric regions. Thus, proper G-overhang length maintenance is required to protect telomeres against intertelomeric recombination, which is achieved by the balanced functions of GTBP1 and telomerase activity.
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Affiliation(s)
- Yong Woo Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Woo Taek Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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Leehy KA, Lee JR, Song X, Renfrew KB, Shippen DE. MERISTEM DISORGANIZATION1 encodes TEN1, an essential telomere protein that modulates telomerase processivity in Arabidopsis. THE PLANT CELL 2013; 25:1343-54. [PMID: 23572541 PMCID: PMC3663272 DOI: 10.1105/tpc.112.107425] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Telomeres protect chromosome ends from being recognized as DNA damage, and they facilitate the complete replication of linear chromosomes. CST [for CTC1(Cdc13)/STN1/TEN1] is a trimeric chromosome end binding complex implicated in both aspects of telomere function. Here, we characterize TEN1 in the flowering plant Arabidopsis thaliana. We report that TEN1 (for telomeric pathways in association with Stn1, which stands for suppressor of cdc thirteen) is encoded by a previously characterized gene, MERISTEM DISORGANIZATION1 (MDO1). A point mutation in MDO1, mdo1-1/ten1-3 (G77E), triggers stem cell differentiation and death as well as a constitutive DNA damage response. We provide biochemical and genetic evidence that ten1-3 is likely to be a null mutation. As with ctc1 and stn1 null mutants, telomere tracts in ten1-3 are shorter and more heterogeneous than the wild type. Mutants also exhibit frequent telomere fusions, increased single-strand telomeric DNA, and telomeric circles. However, unlike stn1 or ctc1 mutants, telomerase enzyme activity is elevated in ten1-3 mutants due to an increase in repeat addition processivity. In addition, TEN1 is detected at a significantly smaller fraction of telomeres than CTC1. These data indicate that TEN1 is critical for telomere stability and also plays an unexpected role in modulating telomerase enzyme activity.
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Ševčíková T, Bišová K, Fojtová M, Lukešová A, Hrčková K, Sýkorová E. Completion of cell division is associated with maximum telomerase activity in naturally synchronized cultures of the green alga Desmodesmus quadricauda. FEBS Lett 2013; 587:743-8. [PMID: 23395610 DOI: 10.1016/j.febslet.2013.01.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/17/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
Abstract
Telomerase maintains the ends of eukaryotic chromosomes, and its activity is an important parameter correlating with the proliferative capacity of cells. We have investigated cell cycle-specific changes in telomerase activity using cultures of Desmodesmus quadricauda, a model alga naturally synchronized by light/dark entrainment. A quantitative telomerase assay revealed high activity in algal cultures, with slight changes during the light period. Significantly increased telomerase activity was observed at the end of the dark phase, when cell division was complete. In contrast to other models, a natural separation between nuclear and cellular division typical for the cell cycle in D. quadricauda made this observation possible.
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Affiliation(s)
- Tereza Ševčíková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, vvi, 612 65 Brno, Czech Republic
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Cheng C, Peng D, Huang L, Ma X. Years-identification mathematical model ofpaeonia lactiflorapall. based on the allometric-scaling. Microsc Res Tech 2012; 76:201-8. [DOI: 10.1002/jemt.22154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/29/2012] [Indexed: 12/22/2022]
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Ogrocká A, Sýkorová E, Fajkus J, Fojtová M. Developmental silencing of the AtTERT gene is associated with increased H3K27me3 loading and maintenance of its euchromatic environment. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:4233-41. [PMID: 22511802 PMCID: PMC3398451 DOI: 10.1093/jxb/ers107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Telomerase, an enzyme responsible for the maintenance of linear chromosome ends, is precisely regulated during plant development. In animals, involvement of the epigenetic state of the telomerase reverse transcriptase (TERT) gene in the complex regulation of telomerase activity has been reported. To reveal whether epigenetic mechanisms participate in the regulation of plant telomerase, the relationship between telomerase activity in tissues of Arabidopsis thaliana and DNA methylation and histone modifications in the A. thaliana TERT (AtTERT) upstream region was studied. As expected, a gradual decrease of telomerase activity during leaf maturation was observed. A different pattern with a more progressive loss of telomerase activity and AtTERT transcription during leaf development was revealed in MET1 gene-knockout mutants. Analysis of DNA methylation in the AtTERT upstream region showed low levels of methylated cytosines without notable differences between telomerase-positive and telomerase-negative wild-type tissues. Surprisingly, a high level of CG methylation was found in the AtTERT coding region, although this type of methylation is a characteristic attribute of constitutively expressed genes. Analysis of chromatin modifications in the AtTERT upstream region and in exon 5 showed increased loading of the H3K27me3 mark in the telomerase-negative mature leaf compared to telomerase-positive seedlings, whereas H3K4me3, H3K9Ac, and H3K9me2 were approximately at the same level. Consistently, the chromatin structure of the AtTERT gene was maintained. These results are discussed in the context of the general involvement of epigenetic mechanisms in the regulation of gene expression and with respect to similar studies performed in animal models.
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Affiliation(s)
- Anna Ogrocká
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Eva Sýkorová
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 65, 612 65 Brno, Czech Republic
| | - Jiří Fajkus
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 65, 612 65 Brno, Czech Republic
| | - Miloslava Fojtová
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- To whom correspondence should be addressed. E-mail:
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Fulnečková J, Hasíková T, Fajkus J, Lukešová A, Eliáš M, Sýkorová E. Dynamic evolution of telomeric sequences in the green algal order Chlamydomonadales. Genome Biol Evol 2012; 4:248-64. [PMID: 22247428 PMCID: PMC3318450 DOI: 10.1093/gbe/evs007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Telomeres, which form the protective ends of eukaryotic chromosomes, are a ubiquitous and conserved structure of eukaryotic genomes but the basic structural unit of most telomeres, a repeated minisatellite motif with the general consensus sequence TnAmGo, may vary between eukaryotic groups. Previous studies on several species of green algae revealed that this group exhibits at least two types of telomeric sequences, a presumably ancestral type shared with land plants (Arabidopsis type, TTTAGGG) and conserved in, for example, Ostreococcus and Chlorella species, and a novel type (Chlamydomonas type, TTTTAGGG) identified in Chlamydomonas reinhardtii. We have employed several methodical approaches to survey the diversity of telomeric sequences in a phylogenetically wide array of green algal species, focusing on the order Chlamydomonadales. Our results support the view that the Arabidopsis-type telomeric sequence is ancestral for green algae and has been conserved in most lineages, including Mamiellophyceae, Chlorodendrophyceae, Trebouxiophyceae, Sphaeropleales, and most Chlamydomonadales. However, within the Chlamydomonadales, at least two independent evolutionary changes to the Chlamydomonas type occurred, specifically in a subgroup of the Reinhardtinia clade (including C. reinhardtii and Volvox carteri) and in the Chloromonadinia clade. Furthermore, a complex structure of telomeric repeats, including a mix of the ancestral Arabidopsis-type motifs and derived motifs identical to the human-type telomeric repeats (TTAGGG), was found in the chlamydomonadalean clades Dunaliellinia and Stephanosphaeria. Our results indicate that telomere evolution in green algae, particularly in the order Chlamydomonadales, is far more dynamic and complex than thought before. General implications of our findings for the mode of telomere evolution are discussed.
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Affiliation(s)
- Jana Fulnečková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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Fojtová M, Peška V, Dobšáková Z, Mozgová I, Fajkus J, Sýkorová E. Molecular analysis of T-DNA insertion mutants identified putative regulatory elements in the AtTERT gene. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:5531-45. [PMID: 21865176 PMCID: PMC3223050 DOI: 10.1093/jxb/err235] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Analysis of plants bearing a T-DNA insertion is a potent tool of modern molecular biology, providing valuable information about the function and involvement of genes in metabolic pathways. A collection of 12 Arabidopsis thaliana lines with T-DNA insertions in the gene coding for the catalytic subunit of telomerase (AtTERT) and in adjacent regions was screened for telomerase activity [telomere repeat amplification protocol (TRAP) assay], telomere length (terminal restriction fragments), and AtTERT transcription (quantitative reverse transcription-PCR). Lines with the insertion located upstream of the start codon displayed unchanged telomere stability and telomerase activity, defining a putative minimal AtTERT promoter and the presence of a regulatory element linked to increased transcription in the line SALK_048471. Lines bearing a T-DNA insertion inside the protein-coding region showed telomere shortening and lack of telomerase activity. Transcription in most of these lines was unchanged upstream of the T-DNA insertion, while it was notably decreased downstream. The expression profile varied markedly in mutant lines harbouring insertions at the 5' end of AtTERT which showed increased transcription and abolished tissue specificity. Moreover, the line FLAG_385G01 (T-DNA insertion inside intron 1) revealed the presence of a highly abundant downstream transcript with normal splicing but without active telomerase. The role of regulatory elements found along the AtTERT gene is discussed in respect to natural telomerase expression and putative intron-mediated enhancement.
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Affiliation(s)
- Miloslava Fojtová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265 Brno, Czech Republic
- Department of Functional Genomics and Proteomics, Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
| | - Vratislav Peška
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265 Brno, Czech Republic
- Department of Functional Genomics and Proteomics, Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
| | - Zuzana Dobšáková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265 Brno, Czech Republic
- To whom correspondence should be addressed. E-mail:
| | - Iva Mozgová
- Department of Functional Genomics and Proteomics, Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
| | - Jiří Fajkus
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265 Brno, Czech Republic
- Department of Functional Genomics and Proteomics, Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265 Brno, Czech Republic
- Department of Functional Genomics and Proteomics, Faculty of Science and CEITEC - Central European Institute of Technology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
- To whom correspondence should be addressed. E-mail:
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QTL Mapping and Candidate Gene Analysis of Telomere Length Control Factors in Maize (Zea mays L.). G3-GENES GENOMES GENETICS 2011; 1:437-50. [PMID: 22384354 PMCID: PMC3276162 DOI: 10.1534/g3.111.000703] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/16/2011] [Indexed: 11/30/2022]
Abstract
Telomere length is a quantitative trait important for many cellular functions. Failure to regulate telomere length contributes to genomic instability, cellular senescence, cancer, and apoptosis in humans, but the functional significance of telomere regulation in plants is much less well understood. To gain a better understanding of telomere biology in plants, we used quantitative trait locus (QTL) mapping to identify genetic elements that control telomere length variation in maize (Zea mays L.). For this purpose, we measured the median and mean telomere lengths from 178 recombinant inbred lines of the IBM mapping population and found multiple regions that collectively accounted for 33–38% of the variation in telomere length. Two-way analysis of variance revealed interaction between the quantitative trait loci at genetic bin positions 2.09 and 5.04. Candidate genes within these and other significant QTL intervals, along with select genes known a priori to regulate telomere length, were tested for correlations between expression levels and telomere length in the IBM population and diverse inbred lines by quantitative real-time PCR. A slight but significant positive correlation between expression levels and telomere length was observed for many of the candidate genes, but Ibp2 was a notable exception, showing instead a negative correlation. A rad51-like protein (TEL-MD_5.04) was strongly supported as a candidate gene by several lines of evidence. Our results highlight the value of QTL mapping plus candidate gene expression analysis in a genetically diverse model system for telomere research.
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Majerová E, Fojtová M, Mozgová I, Bittová M, Fajkus J. Hypomethylating drugs efficiently decrease cytosine methylation in telomeric DNA and activate telomerase without affecting telomere lengths in tobacco cells. PLANT MOLECULAR BIOLOGY 2011; 77:371-80. [PMID: 21866390 DOI: 10.1007/s11103-011-9816-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 08/11/2011] [Indexed: 05/23/2023]
Abstract
Telomere homeostasis is regulated at multiple levels, including the local chromatin structure of telomeres and subtelomeres. Recent reports demonstrated that a decrease in repressive chromatin marks, such as levels of cytosine methylation in subtelomeric regions, results in telomere elongation in mouse cells. Here we show that a considerable fraction of cytosines is methylated not only in subtelomeric, but also in telomeric DNA of tobacco BY-2 cells. Drug-induced hypomethylation (demonstrated at subtelomeric, telomeric, and global DNA levels) results in activation of telomerase. However, in contrast to mouse cells, the decrease in 5-methylcytosine levels and upregulation of telomerase do not result in any changes of telomere lengths. These results demonstrate the involvement of epigenetic mechanisms in the multilevel process of regulation of telomerase activity in plant cells and, at the same time, they indicate that changes in telomerase activity can be overridden by other factors governing telomere length stability.
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Affiliation(s)
- Eva Majerová
- Department of Functional Genomics and Proteomics, Faculty of Science and Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, Czech Republic
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