220
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Analysis of TET Expression/Activity and 5mC Oxidation during Normal and Malignant Germ Cell Development

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          During mammalian development the fertilized zygote and primordial germ cells lose their DNA methylation within one cell cycle leading to the concept of active DNA demethylation. Recent studies identified the TET hydroxylases as key enzymes responsible for active DNA demethylation, catalyzing the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine. Further oxidation and activation of the base excision repair mechanism leads to replacement of a modified cytosine by an unmodified one. In this study, we analyzed the expression/activity of TET1-3 and screened for the presence of 5mC oxidation products in adult human testis and in germ cell cancers. By analyzing human testis sections, we show that levels of 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine are decreasing as spermatogenesis proceeds, while 5-methylcytosine levels remain constant. These data indicate that during spermatogenesis active DNA demethylation becomes downregulated leading to a conservation of the methylation marks in mature sperm. We demonstrate that all carcinoma in situ and the majority of seminomas are hypomethylated and hypohydroxymethylated compared to non-seminomas. Interestingly, 5-formylcytosine and 5-carboxylcytosine were detectable in all germ cell cancer entities analyzed, but levels did not correlate to the 5-methylcytosine or 5-hydroxymethylcytosine status. A meta-analysis of gene expression data of germ cell cancer tissues and corresponding cell lines demonstrates high expression of TET1 and the DNA glycosylase TDG, suggesting that germ cell cancers utilize the oxidation pathway for active DNA demethylation. During xenograft experiments, where seminoma-like TCam-2 cells transit to an embryonal carcinoma-like state DNMT3B and DNMT3L where strongly upregulated, which correlated to increasing 5-methylcytosine levels. Additionally, 5-hydroxymethylcytosine levels were elevated, demonstrating that de novo methylation and active demethylation accompanies this transition process. Finally, mutations of IDH1 ( IDH1 R132) and IDH2 ( IDH2 R172) leading to production of the TET inhibiting oncometabolite 2-hydroxyglutarate in germ cell cancer cell lines were not detected.

          Related collections

          Most cited references40

          • Record: found
          • Abstract: found
          • Article: not found

          Epigenetic reprogramming in mouse primordial germ cells.

          Genome-wide epigenetic reprogramming in mammalian germ cells, zygote and early embryos, plays a crucial role in regulating genome functions at critical stages of development. We show here that mouse primordial germ cells (PGCs) exhibit dynamic changes in epigenetic modifications between days 10.5 and 12.5 post coitum (dpc). First, contrary to previous suggestions, we show that PGCs do indeed acquire genome-wide de novo methylation during early development and migration into the genital ridge. However, following their entry into the genital ridge, there is rapid erasure of DNA methylation of regions within imprinted and non-imprinted loci. For most genes, the erasure commences simultaneously in PGCs in both male and female embryos, which is completed within 1 day of development. Based on the kinetics of this process, we suggest that this is an active demethylation process initiated upon the entry of PGCs into the gonadal anlagen. The timing of reprogramming in PGCs is crucial since it ensures that germ cells of both sexes acquire an equivalent epigenetic state prior to the differentiation of the definitive male and female germ cells in which new parental imprints are established subsequently. Some repetitive elements, however, show incomplete erasure, which may be essential for chromosome stability and for preventing activation of transposons to reduce the risk of germline mutations. Aberrant epigenetic reprogramming in the germ line would cause the inheritance of epimutations that may have consequences for human diseases as suggested by studies on mouse models. Copyright 2002 Elsevier Science Ireland Ltd.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Uncovering the role of 5-hydroxymethylcytosine in the epigenome.

            Just over 2 years ago, TET1 was found to catalyse the oxidation of 5-methylcytosine, a well-known epigenetic mark, into 5-hydroxymethylcytosine in mammalian DNA. The exciting prospect of a novel epigenetic modification that may dynamically regulate DNA methylation has led to the rapid accumulation of publications from a wide array of fields, from biochemistry to stem cell biology. Although we have only started to scratch the surface, interesting clues on the role of 5-hydroxymethylcytosine are quickly emerging.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Epigenetic events in mammalian germ-cell development: reprogramming and beyond.

              The epigenetic profile of germ cells, which is defined by modifications of DNA and chromatin, changes dynamically during their development. Many of the changes are associated with the acquisition of the capacity to support post-fertilization development. Our knowledge of this aspect has greatly increased- for example, insights into how the re-establishment of parental imprints is regulated. In addition, an emerging theme from recent studies is that epigenetic modifiers have key roles in germ-cell development itself--for example, epigenetics contributes to the gene-expression programme that is required for germ-cell development, regulation of meiosis and genomic integrity. Understanding epigenetic regulation in germ cells has implications for reproductive engineering technologies and human health.
                Bookmark

                Author and article information

                Contributors
                Role: Editor
                Journal
                PLoS One
                PLoS ONE
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, USA )
                1932-6203
                2013
                26 December 2013
                : 8
                : 12
                : e82881
                Affiliations
                [1 ]Institute of Pathology, Department of Developmental Pathology, University Hospital, Bonn, Germany
                [2 ]Institute of Pathology, University Hospital, Bonn, Germany
                [3 ]Institute of Neuropathology, University Hospital, Bonn, Germany
                [4 ]Department of Oncology, Haematology and Bone Marrow Transplantation with Section Pneumology, Hubertus Wald-Tumorzentrum, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
                Virginia Commonwealth University, United States of America
                Author notes

                Competing Interests: The authors have declared that no competing interests exist.

                Conceived and designed the experiments: DN LCH Andreas Waha FH GK HS. Performed the experiments: DN Anke Waha NH FF MJG LCH. Analyzed the data: DN GK Andreas Waha HS. Contributed reagents/materials/analysis tools: FF Andreas Waha LCH HS. Wrote the paper: DN HS.

                [¤a]

                Current address: University Hospital Cologne, Institute of Pathology, Cologne, Germany

                [¤b]

                Current address: FMH Innere Medizin, Spez. Hämatologie Medizinische Onkologie/Hämatologie/Palliativmedizin, Tumor- und Brustzentrum ZeTuP Silberturm, St. Gallen, Switzerland

                Article
                PONE-D-13-33334
                10.1371/journal.pone.0082881
                3873252
                24386123
                e3918e22-0dec-4928-b1bd-8c7e1e5631fc
                Copyright @ 2013

                This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

                History
                : 15 August 2013
                : 28 October 2013
                Page count
                Pages: 12
                Funding
                This work was supported by DFG grant Scho-503/9 and Deutsche Krebshilfe #108249 to HS and the National Genome Research Network, “NGFNplus”, Brain Tumor Network plus grant 01GS08187 to AW. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
                Categories
                Research Article
                Biology
                Anatomy and Physiology
                Reproductive System
                Reproductive Physiology
                Biochemistry
                Nucleic Acids
                DNA
                DNA modification
                Genetics
                Epigenetics
                DNA modification
                Gene Expression
                DNA modification
                Cancer Genetics
                Genetic Mutation
                Human Genetics
                Molecular Genetics
                Molecular Cell Biology
                Gene Expression
                DNA modification
                Medicine
                Anatomy and Physiology
                Reproductive System
                Reproductive Physiology
                Oncology
                Basic Cancer Research
                Cancers and Neoplasms
                Urology
                Testicular Cancer

                Uncategorized
                Uncategorized

                Comments

                Comment on this article