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.

CEITEC Central European Institute of Technology Masaryk University Kamenice 5 625 00 Brno Czech Republic

Zobrazit více v PubMed

Aceituno FF, Moseyko N, Rhee SY, Gutierrez RA. The rules of gene expression in plants: organ identity and gene body methylation are key factors for regulation of gene expression in Arabidopsis thaliana . BMC Genomics. 2008;9:438. PubMed PMC

Alonso JM, Stepanova AN, Leisse TJ, Kim CJ, Chen H, Shinn P, Stevenson DK, Zimmerman J, Barajas P, Cheuk R, et al. Genome-wide insertional mutagenesis of Arabidopsis thaliana . Science. 2003;301:653–657. PubMed

Bastow R, Mylne JS, Lister C, Lippman Z, Martienssen RA, Dean C. Vernalization requires epigenetic silencing of FLC by histone methylation. Nature. 2004;427:164–167. PubMed

Broun P, Ganal MW, Tanksley SD. Telomeric arrays display high levels of heritable polymorphism among closely related plant varieties. Proceedings of the National Academy of Sciences, USA. 1992;89:1354–1357. PubMed PMC

Chatagnon A, Bougel S, Perriaud L, Lachuer J, Benhattar J, Dante R. Specific association between the methyl-CpG-binding domain protein 2 and the hypermethylated region of the human telomerase reverse transcriptase promoter in cancer cells. Carcinogenesis. 2009;30:28–34. PubMed

Cifuentes-Rojas C, Kannan K, Tseng L, Shippen DE. Two RNA subunits and POT1a are components of Arabidopsis telomerase. Proceedings of the National Academy of Sciences, USA. 2011;108:73–78. PubMed PMC

Clark SJ, Harrison J, Paul CL, Frommer M. High sensitivity mapping of methylated cytosines. Nucleic Acids Research. 1994;22:2990–2997. PubMed PMC

Cokus SJ, Feng S, Zhang X, Chen Z, Merriman B, Haudenschild CD, Pradhan S, Nelson SF, Pellegrini M, Jacobsen SE. Shotgun bisulphite sequencing of the Arabidopsis genome reveals DNA methylation patterning. Nature. 2008;452:215–219. PubMed PMC

Deal RB, Henikoff S. Histone variants and modifications in plant gene regulation. Current Opinion in Plant Biology. 2011;14:116–122. PubMed PMC

Dessain SK, Yu H, Reddel RR, Beijersbergen RL, Weinberg RA. Methylation of the human telomerase gene CpG island. Cancer Research. 2000;60:537–541. PubMed

Devereux TR, Horikawa I, Anna CH, Annab LA, Afshari CA, Barrett JC. DNA methylation analysis of the promoter region of the human telomerase reverse transcriptase (hTERT) gene. Cancer Research. 1999;59:6087–6090. PubMed

Fajkus J, Kovarik A, Kralovics R. Telomerase activity in plant cells. FEBS Letters. 1996;391:307–309. PubMed

Fajkus J, Fulneckova J, Hulanova M, Berkova K, Riha K, Matyasek R. Plant cells express telomerase activity upon transfer to callus culture, without extensively changing telomere lengths. Molecular and General Genetics. 1998;260:470–474. PubMed

Fitzgerald MS, McKnight TD, Shippen DE. Characterization and developmental patterns of telomerase expression in plants. Proceedings of the National Academy of Sciences, USA. 1996;93:14422–14427. PubMed PMC

Fojtova M, Peska V, Dobsakova Z, Mozgova I, Fajkus J, Sykorova E. Molecular analysis of the T-DNA insertion mutants identified putative regulatory elements in the AtTERT gene. Journal of Experimental Botany. 2011;62:5531–5545. PubMed PMC

Fransz P, ten Hoopen R, Tessadori F. Composition and formation of heterochromatin in Arabidopsis thaliana . Chromosome Research. 2006;14:71–82. PubMed

Gaudin V, Libault M, Pouteau S, Juul T, Zhao G, Lefebvre D, Grandjean O. Mutations in LIKE HETEROCHROMATIN PROTEIN 1 affect flowering time and plant architecture in Arabidopsis. Development. 2001;128:4847–4858. PubMed

Guilleret I, Benhattar J. Demethylation of the human telomerase catalytic subunit (hTERT) gene promoter reduced hTERT expression and telomerase activity and shortened telomeres. Experimental Cell Research. 2003;289:326–334. PubMed

Ha M, Ng DW, Li WH, Chen ZJ. Coordinated histone modifications are associated with gene expression variation within and between species. Genome Research. 2011;21:590–598. PubMed PMC

Heller K, Kilian A, Piatyszek MA, Kleinhofs A. Telomerase activity in plant extracts. Molecular and General Genetics. 1996;252:342–345. PubMed

Heller-Uszynska K, Schnippenkoetter W, Kilian A. Cloning and characterization of rice (Oryza sativa L) telomerase reverse transcriptase, which reveals complex splicing patterns. Plant Journal. 2002;31:75–86. PubMed

Herbert BS, Hochreiter AE, Wright WE, Shay JW. Nonradioactive detection of telomerase activity using the telomeric repeat amplification protocol. Nature Protocols. 2006;1:1583–1590. PubMed

Hetzl J, Foerster AM, Raidl G, Mittelsten Scheid O. CyMATE: a new tool for methylation analysis of plant genomic DNA after bisulphite sequencing. The Plant Journal. 2007;51:526–536. PubMed

Hon G, Wang W, Ren B. Discovery and annotation of functional chromatin signatures in the human genome. PLoS Computational Biology. 2009;5 e1000566. PubMed PMC

Horikawa I, Chiang YJ, Patterson T, Feigenbaum L, Leem SH, Michishita E, Larionov V, Hodes RJ, Barrett JC. Differential cis-regulation of human versus mouse TERT gene expression in vivo: identification of a human-specific repressive element. Proceedings of the National Academy of Sciences, USA. 2005;102:18437–18442. PubMed PMC

Kovarik A, Van Houdt H, Holy A, Depicker A. Drug-induced hypomethylation of a posttranscriptionally silenced transgene locus of tobacco leads to partial release of silencing. FEBS Letters. 2000;467:47–51. PubMed

Lorincz MC, Dickerson DR, Schmitt M, Groudine M. Intragenic DNA methylation alters chromatin structure and elongation efficiency in mammalian cells. Nature Structural and Molecular Biology. 2004;11:1068–1075. PubMed

Lunerova-Bedrichova J, Bleys A, Fojtova M, Khaitova L, Depicker A, Kovarik A. Trans-generation inheritance of methylation patterns in a tobacco transgene following a post-transcriptional silencing event. Plant Journal. 2008;54:1049–1062. PubMed

Mathieu O, Reinders J, Caikovski M, Smathajitt C, Paszkowski J. Transgenerational stability of the Arabidopsis epigenome is coordinated by CG methylation. Cell. 2007;130:851–862. PubMed

Oguchi K, Liu H, Tamura K, Takahashi H. Molecular cloning and characterization of AtTERT, a telomerase reverse transcriptase homolog in Arabidopsis thaliana . FEBS Letters. 1999;457:465–469. PubMed

Oguchi K, Tamura K, Takahashi H. Characterization of Oryza sativa telomerase reverse transcriptase and possible role of its phosphorylation in the control of telomerase activity. Gene. 2004;342:57–66. PubMed

Pfaffl MW. Quantification strategies in real-time PCR. In: S.A. Bustin., editor. A-Z of Quantitative PCR. International University Line, La Jolla, CA; 2004. pp. 87–112.

Riha K, Fajkus J, Siroky J, Vyskot B. Developmental control of telomere lengths and telomerase activity in plants. The Plant Cell. 1998;10:1691–1698. PubMed PMC

Rossignol P, Collier S, Bush M, Shaw P, Doonan JH. Arabidopsis POT1A interacts with TERT-V(I8), an N-terminal splicing variant of telomerase. Journal of Cellular Sciences. 2007;120:3678–3687. PubMed

Roudier F, Ahmed I, Berard C, Sarazin A, Mary-Huard T, Cortijo S, Bouyer D, Caillieux E, Duvernois-Berthet E, Al-Shikhley L, et al. Integrative epigenomic mapping defines four main chromatin states in Arabidopsis. EMBO Journal. 2011;30:1928–1938. PubMed PMC

Saze H, Mittelsten Scheid O, Paszkowski J. Maintenance of CpG methylation is essential for epigenetic inheritance during plant gametogenesis. Nature Genetics. 2003;34:65–69. PubMed

Sykorova E, Lim KY, Chase MW, Knapp S, Leitch IJ, Leitch AR, Fajkus J. The absence of Arabidopsis-type telomeres in Cestrum and closely related genera Vestia and Sessea (Solanaceae): first evidence from eudicots. Plant Journal. 2003;34:283–291. PubMed

Turck F, Roudier F, Farrona S, Martin-Magniette ML, Guillaume E, Buisine N, Gagnot S, Martienssen RA, Coupland G, Colot V. Arabidopsis TFL2/LHP1 specifically associates with genes marked by trimethylation of histone H3 lysine 27. PLoS Genetics. 2007;3 e86. PubMed PMC

Wang S, Zhao Y, Hu C, Zhu J. Differential repression of human and mouse TERT genes during cell differentiation. Nucleic Acids Research. 2009;37:2618–2629. PubMed PMC

Weinhofer I, Hehenberger E, Roszak P, Hennig L, Kohler C. H3K27me3 profiling of the endosperm implies exclusion of polycomb group protein targeting by DNA methylation. PLoS Genetics. 2010;6 e1001152. PubMed PMC

Vaughn MW, Tanurdzic M, Lippman Z, Jiang H, Carrasquillo R, Rabinowicz PD, Dedhia N, McCombie WR, Agier N, Bulski A, Colot V, Doerge RW, Martienssen RA. Epigenetic natural variation in Arabidopsis thaliana . PLoS Biology. 2007;5 e174. PubMed PMC

Zhang X, Yazaki J, Sundaresan A, Cokus S, Chan SW, Chen H, Henderson IR, Shinn P, Pellegrini M, Jacobsen SE, et al. Genome-wide high-resolution mapping and functional analysis of DNA methylation in Arabidopsis. Cell. 2006;126:1189–1201. PubMed

Zhang X, Clarenz O, Cokus S, Bernatavichute YV, Pellegrini M, Goodrich J, Jacobsen SE. Whole-genome analysis of histone H3 lysine 27 trimethylation in Arabidopsis. PLoS Biology. 2007;5 e129. PubMed PMC

Zhu J, Zhao Y, Wang S. Chromatin and epigenetic regulation of the telomerase reverse transcriptase gene. Protein Cell. 2011;1:22–32. PubMed PMC

Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes

Telomerase RNAs in land plants

Telomeres in Plants and Humans: Not So Different, Not So Similar

An armadillo-domain protein participates in a telomerase interaction network

Tissue-specific expression of telomerase reverse transcriptase gene variants in Nicotiana tabacum

cDNA Library Screening Identifies Protein Interactors Potentially Involved in Non-Telomeric Roles of Arabidopsis Telomerase

Compromised telomere maintenance in hypomethylated Arabidopsis thaliana plants

Epigenetic switches of tobacco transgenes associate with transient redistribution of histone marks in callus culture