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Sun S, Ma W, Mi C, Mao P. Telomerase reverse transcriptase, a telomere length maintenance protein in alfalfa (Medicago sativa), confers Arabidopsis thaliana seeds aging tolerance via modulation of telomere length. Int J Biol Macromol 2024; 277:134388. [PMID: 39116978 DOI: 10.1016/j.ijbiomac.2024.134388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 07/17/2024] [Accepted: 07/30/2024] [Indexed: 08/10/2024]
Abstract
Numerous studies have investigated seed aging, with a particular emphasis on the involvement of reactive oxygen species. Reactive oxygen species diffuse into the nucleus and damage telomeres, resulting in loss of genetic integrity. Telomerase reverse transcriptase (TERT) plays an essential role in maintaining plant genomic stability. Genome-wide analyses of TERT genes in alfalfa (Medicago sativa) have not yet been conducted, leaving a gap in our understanding of the mechanisms underlying seed aging associated with TERT genes. In this study, four MsTERT genes were identified in the alfalfa genome. The expression profiles of the four MsTERT genes during seed germination indicated that MS. gene79077 was significantly upregulated by seed aging. Transgenic seeds overexpressing MS. gene79077 in Arabidopsis exhibited enhanced tolerance to seed aging by reducing the levels of H2O2 and increasing telomere length and telomerase activity. Furthermore, transcript profiling of aging-treated Arabidopsis wild-type and overexpressing seeds showed an aging response in genes related to glutathione-dependent detoxification and antioxidant defense pathways. These results revealed that MS. gene79077 conferred Arabidopsis seed-aging tolerance via modulation of antioxidant defense and telomere homeostasis. This study provides a new way to understand stress-responsive MsTERT genes for the potential genetic improvement of seed vigor.
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Affiliation(s)
- Shoujiang Sun
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China
| | - Wen Ma
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China
| | - Chunjiao Mi
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China
| | - Peisheng Mao
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
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2
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Fajkus P, Peška V, Fajkus J, Sýkorová E. Origin and Fates of TERT Gene Copies in Polyploid Plants. Int J Mol Sci 2021; 22:1783. [PMID: 33670111 PMCID: PMC7916837 DOI: 10.3390/ijms22041783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 12/14/2022] Open
Abstract
The gene coding for the telomerase reverse transcriptase (TERT) is essential for the maintenance of telomeres. Previously we described the presence of three TERT paralogs in the allotetraploid plant Nicotiana tabacum, while a single TERT copy was identified in the paleopolyploid model plant Arabidopsis thaliana. Here we examine the presence, origin and functional status of TERT variants in allotetraploid Nicotiana species of diverse evolutionary ages and their parental genome donors, as well as in other diploid and polyploid plant species. A combination of experimental and in silico bottom-up analyses of TERT gene copies in Nicotiana polyploids revealed various patterns of retention or loss of parental TERT variants and divergence in their functions. RT-qPCR results confirmed the expression of all the identified TERT variants. In representative plant and green algal genomes, our synteny analyses show that their TERT genes were located in a conserved locus that became advantageous after the divergence of eudicots, and the gene was later translocated in several plant groups. In various diploid and polyploid species, translocation of TERT became fixed in target loci that show ancient synapomorphy.
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Affiliation(s)
- Petr Fajkus
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; (P.F.); (V.P.)
| | - Vratislav Peška
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; (P.F.); (V.P.)
| | - Jiří Fajkus
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; (P.F.); (V.P.)
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; (P.F.); (V.P.)
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Schrumpfová PP, Fajkus J. Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes. Biomolecules 2020; 10:biom10101425. [PMID: 33050064 PMCID: PMC7658794 DOI: 10.3390/biom10101425] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- Correspondence:
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65 Brno, Czech Republic
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4
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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: 45] [Impact Index Per Article: 9.0] [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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5
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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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6
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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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7
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Procházková Schrumpfová P, Schořová Š, Fajkus J. Telomere- and Telomerase-Associated Proteins and Their Functions in the Plant Cell. FRONTIERS IN PLANT SCIENCE 2016; 7:851. [PMID: 27446102 PMCID: PMC4924339 DOI: 10.3389/fpls.2016.00851] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/31/2016] [Indexed: 05/20/2023]
Abstract
Telomeres, as physical ends of linear chromosomes, are targets of a number of specific proteins, including primarily telomerase reverse transcriptase. Access of proteins to the telomere may be affected by a number of diverse factors, e.g., protein interaction partners, local DNA or chromatin structures, subcellular localization/trafficking, or simply protein modification. Knowledge of composition of the functional nucleoprotein complex of plant telomeres is only fragmentary. Moreover, the plant telomeric repeat binding proteins that were characterized recently appear to also be involved in non-telomeric processes, e.g., ribosome biogenesis. This interesting finding was not totally unexpected since non-telomeric functions of yeast or animal telomeric proteins, as well as of telomerase subunits, have been reported for almost a decade. Here we summarize known facts about the architecture of plant telomeres and compare them with the well-described composition of telomeres in other organisms.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityBrno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrno, Czech Republic
- *Correspondence: Petra Procházková Schrumpfová,
| | - Šárka Schořová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityBrno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, 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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8
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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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9
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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: 9] [Impact Index Per Article: 1.0] [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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10
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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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