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Uysal F, Sukur G, Bozdemir N, Cinar O. Unveiling the impact of DNA methylation machinery: Dnmt1 and Dnmt3a in orchestrating oocyte development and cellular homeostasis. Genesis 2024; 62:e23579. [PMID: 37985411 DOI: 10.1002/dvg.23579] [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: 09/30/2023] [Revised: 10/27/2023] [Accepted: 11/02/2023] [Indexed: 11/22/2023]
Abstract
DNA methylation can be considered the most prominent in controlling the gene expression responsible for the balance between cell proliferation and cell death. In this study, we aimed to analyze the distinct contributions of Dnmt1 and Dnmt3a enzymes in oocyte maturation, survival, autophagy, reactive oxygen species (ROS) production, and compensation capacity of Dnmt3b and Dnmt3l enzymes in mouse oocytes. Following confirming the suppression of Dnmt1or Dnmt3a through siRNA application, the assessment involved immunofluorescence staining for Dnmts, 5mC, p62, and ROS levels. Cell death rates showed a noticeable increase while oocyte maturation rates exhibited significant reduction. Global DNA methylation showed a decline, concomitant with elevated p62 and ROS levels upon Dnmt1 or Dnmt3a knockdown. Remarkably, silencing of Dnmt1 led to an upsurge in Dnmt3a expression, whereas Dnmt3a knockdown triggered an increase in Dnmt1 levels. Furthermore, Dnmt3l expression exhibited a notable decrease after silencing of either Dnmt1 or Dnmt3a, while Dnmt3b levels remained comparable between control and siRNA-treated groups. Collectively, this study underscores the pivotal roles of Dnmt1 and Dnmt3a in orchestrating various facets of oocyte development, encompassing maturation, survival, autophagy, and ROS production. These findings offer valuable insights into the intricate regulatory network governed by DNA methylation machinery within the context of oocyte physiology.
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Affiliation(s)
- Fatma Uysal
- Department of Histology and Embryology, Ankara Medipol University School of Medicine, Ankara, Turkey
| | - Gozde Sukur
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Nazlican Bozdemir
- Department of Histology and Embryology, Ankara Medipol University School of Medicine, Ankara, Turkey
| | - Ozgur Cinar
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
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Uysal F, Cinar O, Can A. Knockdown of Dnmt1 and Dnmt3a gene expression disrupts preimplantation embryo development through global DNA methylation. J Assist Reprod Genet 2021; 38:3135-3144. [PMID: 34533678 DOI: 10.1007/s10815-021-02316-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 09/08/2021] [Indexed: 11/24/2022] Open
Abstract
PURPOSE DNA methylation is one of the epigenetic mechanisms that plays critical roles in preimplantation embryo development executed by DNA methyltransferase (Dnmt) enzymes. Dnmt1, responsible for the maintenance of methylation, and Dnmt3a, for de novo methylation, are gradually erased from the zygote in succeeding stages and then reestablished in the blastocyst. This study was designed to address the vital role of Dnmt1 and Dnmt3a enzymes by silencing their gene expressions in embryonic development in mice. METHODS Groups were (i) control, (ii) Dnmt1-siRNA, (iii) Dnmt3a-siRNA, and (iv) non-targeted (NT) siRNA. Knockdown of Dnmt genes using siRNAs was confirmed by measuring the targeted proteins using Western blot and immunofluorescence. Following knockdown of Dnmt1 and Dnmt3a in zygotes, the developmental competence and global DNA methylation levels were analyzed after 96 h in embryo cultures. RESULTS A significant number of embryos arrested at the 2-cell stage or had undergone degeneration in the Dnmt1 and Dnmt3a knocked-down groups. By 3D observations in super-resolution microscopy, we noted that Dnmt1 was exclusively found in juxtanuclear cytoplasm, while the Dnmt3a signal was preferentially localized in the nucleus, both in trophoblasts (TBs) and embryoblasts (EBs). Interestingly, the global DNA methylation level decreased in the Dnmt1 knockdown group, while it increased in the Dnmt3a knockdown group. CONCLUSION Precisely aligned expression of Dnmt genes is highly essential for the fate of an embryo in the early developmental period. Our data indicates that further analysis is mandatory to designate the specific targets of these methylation/demethylation processes in mouse and human preimplantation embryos.
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Affiliation(s)
- Fatma Uysal
- Laboratory for Stem Cells and Reproductive Cell Biology, Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Ozgur Cinar
- Laboratory for Stem Cells and Reproductive Cell Biology, Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Alp Can
- Laboratory for Stem Cells and Reproductive Cell Biology, Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey.
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Ruan Z, Zhao X, Li Z, Qin X, Shao Q, Ruan Q, Deng Y, Jiang J, Huang B, Lu F, Shi D. Effect of sex differences in donor foetal fibroblast on the early development and DNA methylation status of buffalo (Bubalus bubalis) nuclear transfer embryos. Reprod Domest Anim 2018; 54:11-22. [PMID: 30051521 DOI: 10.1111/rda.13286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 07/08/2018] [Indexed: 11/27/2022]
Abstract
Low efficiency of somatic cell nuclear transfer (SCNT) embryos is largely attributable to imperfect reprogramming of the donor nucleus. The differences in epigenetic reprogramming between female and male buffalo cloned embryos remain unclear. We explored the effects of donor cell sex differences on the development of SCNT embryos. We and then compared the expression of DNA methylation (5-methylcytosine-5mC and 5-hydroxymethylcytosine-5hmC) and the expression level of relevant genes, and histone methylation (H3K9me2 and H3K9me3) level in SCNT-♀ and SCNT-♂ preimplantation embryos with in vitro fertilization (IVF) counterparts. In the study, we showed that developmental potential of SCNT-♀ embryos was greater than that of SCNT-♂ embryos (p < 0.05). 5mC was mainly expressed in SCNT-♀ embryos, whereas 5hmC was majorly expressed in SCNT-♂ embryos (p < 0.05). The levels of DNA methylation (5mC and 5hmC), Dnmt3b, TET1 and TET3 in the SCNT-♂ embryos were higher than those of SCNT-♀ embryos (p < 0.05). In addition, there were no significant differences in the expression of H3K9me2 at eight-stage of the IVF, SCNT-♀ and SCNT-♂embryos (p < 0.05). However, H3K9me3 was upregulated in SCNT-♂ embryos at the eight-cell stage (p < 0.05). Thus, KDM4B ectopic expression decreased the level of H3K9me3 and significantly improved the developmental rate of two-cell, eight-cell and blastocysts of SCNT-♂ embryos (p < 0.05). Overall, the lower levels of DNA methylation (5mC and 5hmC) and H3K9me3 may introduce the greater developmental potential in buffalo SCNT-♀ embryos than that of SCNT-♂ embryos.
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Affiliation(s)
- Ziyun Ruan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China.,School of Basic Medicine, Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Xin Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Zhengda Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Xiling Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Qiming Shao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Qiuyan Ruan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Yanfei Deng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Jianrong Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China
| | - Ben Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China.,Guangxi High Education Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, Guangxi, China
| | - Fenghua Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China.,Guangxi High Education Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, Guangxi, China
| | - Deshun Shi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, China.,Guangxi High Education Laboratory for Animal Reproduction and Biotechnology, Guangxi University, Nanning, Guangxi, China
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Sepulveda-Rincon LP, Solanas EDL, Serrano-Revuelta E, Ruddick L, Maalouf WE, Beaujean N. Early epigenetic reprogramming in fertilized, cloned, and parthenogenetic embryos. Theriogenology 2016; 86:91-8. [DOI: 10.1016/j.theriogenology.2016.04.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/25/2016] [Accepted: 03/14/2016] [Indexed: 12/17/2022]
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5
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Effect of DNMT inhibitor on bovine parthenogenetic embryo development. Biochem Biophys Res Commun 2015; 466:505-11. [DOI: 10.1016/j.bbrc.2015.09.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/10/2015] [Indexed: 11/20/2022]
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6
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Wan Y, Deng M, Zhang G, Ren C, Zhang H, Zhang Y, Wang L, Wang F. Abnormal expression of DNA methyltransferases and genomic imprinting in cloned goat fibroblasts. Cell Biol Int 2015; 40:74-82. [DOI: 10.1002/cbin.10540] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 08/16/2015] [Accepted: 08/22/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Yongjie Wan
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Mingtian Deng
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Guomin Zhang
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Caifang Ren
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Hao Zhang
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Yanli Zhang
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Lizhong Wang
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Feng Wang
- Jiangsu Livestock Embryo Engineering Laboratory; College of Animal Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
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Petrussa L, Van de Velde H, De Rycke M. Dynamic regulation of DNA methyltransferases in human oocytes and preimplantation embryos after assisted reproductive technologies. Mol Hum Reprod 2014; 20:861-74. [PMID: 24994815 DOI: 10.1093/molehr/gau049] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
DNA methylation is a key epigenetic modification which is essential for normal embryonic development. Major epigenetic reprogramming takes place during gametogenesis and in the early embryo; the complex DNA methylation patterns are established and maintained by DNA methyltransferases (DNMTs). However, the influence of assisted reproductive technologies (ART) on DNA methylation reprogramming enzymes has predominantly been studied in mice and less so in human oocytes and embryos. The expression and localization patterns of the four known DNMTs were analysed in human oocytes and IVF/ICSI embryos by immunocytochemistry and compared between a reference group of good quality fresh embryos and groups of abnormally developing embryos or embryo groups after cryopreservation. In humans, DNMT1o rather than DNMT1s seems to be the key player for maintaining methylation in early embryos. DNMT3b, rather than DNMT3a and DNMT3L, appears to ensure global DNA remethylation in the blastocysts before implantation. DNMT3L, an important regulator of maternal imprint methylation in mouse, was not detected in human oocytes (GV, MI and MII stage). Our study confirms the existence of species differences for mammalian DNA methylation enzymes. In poor quality fresh embryos, the switch towards nuclear DNMT3b expression was delayed and nuclear DNMT1, DNMT1s and DNMT3b expression was less common. Compared with the reference embryos, a smaller number of cryopreserved embryos showed nuclear DNMT1, while a delayed switch to nuclear DNMT3b and an extended DNMT1s temporal expression pattern were also observed. The spatial and temporal expression patterns of DNMTs seem to be disturbed in abnormally developing embryos and in embryos that have been cryopreserved. Further research must be performed in order to understand whether the potentially disturbed embryonic DNMT expression after cryopreservation has any long-term developmental consequences.
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Affiliation(s)
- Laetitia Petrussa
- Department of Reproduction and Genetics (REGE), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Hilde Van de Velde
- Department of Reproduction and Genetics (REGE), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium Centre for Reproductive Medicine (CRM), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Martine De Rycke
- Department of Reproduction and Genetics (REGE), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium Centre for Medical Genetics (CMG), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium
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Giraldo AM, DeCourcy K, Ball SF, Hylan D, Ayares DL. Gene expression of Dnmt1 isoforms in porcine oocytes, embryos, and somatic cells. Cell Reprogram 2013; 15:309-21. [PMID: 23808878 DOI: 10.1089/cell.2012.0088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the mouse, the dynamics of genomic methylation and the initial events of gametic imprinting are controlled by the activity of an oocyte isoform of the DNA methyltransferase-1 (Dnmt1o) enzyme. The objectives of this study were to identify the alternative splicing variants of Dnmt1 in porcine oocytes and determine the gene expression pattern of the different Dnmt1 isoforms during embryo development. A rapid amplification of cDNA ends (RACE ) system was used to amplify the 5' cDNA end of Dnmt1 isoforms in porcine oocytes. RNA levels of the Dnmt1 isoforms were analyzed in porcine oocytes and embryos. DNMT1 protein expression of oocytes and somatic cells were analyzed by western blot and immunostaining. Two new Dnmt1o RNA isoforms were identified--Dnmt1o1 and Dnmt1o2. The previously reported somatic Dnmt1 isoform (Dnmt1s) was expressed at low but constant levels in oocytes and embryos from the two-cell to the blastocyst stage. Abundant RNA levels of Dnmt1o1 and Dnmt1o2 were detected in oocytes and embryos from the two- to the eight- to 16-cell stage. Levels of these Dnmt1o transcripts were low at the morula and blastocyst stages. Although Dnmt1s was present in all the somatic cell types analyzed, Dnmt1o1 and Dnmt1o2 were not detected in any somatic tissues. As predicted by the RNA sequence and verified by western blot analysis, Dnmt1o1 and Dnmt1o2 RNAs translate one DNMT1o enzyme. Western blot analysis confirmed that both the oocyte and the somatic forms of DNMT1 protein are present in porcine oocytes and early embryos, whereas somatic cells produce only DNMT1s protein. DNMT1o is localized mainly in the nuclei of oocytes and early embryos, whereas DNMT1s is expressed in the ooplasm cortex of oocytes and cytoplasm of early embryos.
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O'Connor T, Wilmut I, Taylor J. Quantitative Evaluation of Reference Genes for Real-Time PCR DuringIn VitroMaturation of Ovine Oocytes. Reprod Domest Anim 2012; 48:477-83. [DOI: 10.1111/rda.12112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 09/17/2012] [Indexed: 12/18/2022]
Affiliation(s)
- T O'Connor
- MRC Centre for Regenerative Medicine; The University of Edinburgh; Edinburgh; UK
| | - I Wilmut
- MRC Centre for Regenerative Medicine; The University of Edinburgh; Edinburgh; UK
| | - J Taylor
- MRC Centre for Regenerative Medicine; The University of Edinburgh; Edinburgh; UK
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10
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Van De Voorde L, Speeckaert R, Van Gestel D, Bracke M, De Neve W, Delanghe J, Speeckaert M. DNA methylation-based biomarkers in serum of patients with breast cancer. Mutat Res 2012; 751:304-325. [PMID: 22698615 DOI: 10.1016/j.mrrev.2012.06.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 06/03/2012] [Accepted: 06/05/2012] [Indexed: 12/18/2022]
Abstract
Alterations of genetic and epigenetic features can provide important insights into the natural history of breast cancer. Although DNA methylation analysis is a rapidly developing field, a reproducible epigenetic blood-based assay for diagnosis and follow-up of breast cancer has yet to be successfully developed into a routine clinical test. The aim of this study was to review multiple serum DNA methylation assays and to highlight the value of those novel biomarkers in diagnosis, prognosis and prediction of therapeutic outcome. Serum is readily accessible for molecular diagnosis in all individuals from a peripheral blood sample. The list of hypermethylated genes in breast cancer is heterogeneous and no single gene is methylated in all breast cancer types. There is increasing evidence that a panel of epigenetic markers is essential to achieve a higher sensitivity and specificity in breast cancer detection. However, the reported percentages of methylation are highly variable, which can be partly explained by the different sensitivities and the different intra-/inter-assay coefficients of variability of the analysis methods. Moreover, there is a striking lack of receiver operating characteristic (ROC) curves of the proposed biomarkers. Another point of criticism is the fact that 'normal' patterns of DNA methylation of some tumor suppressor and other cancer-related genes are influenced by several factors and are often poorly characterized. A relatively frequent methylation of those genes has been observed in high-risk asymptomatic women. Finally, there is a call for larger prospective cohort studies to determine methylation patterns during treatment and follow-up. Identification of patterns specific for a differential response to therapeutic interventions should be useful. Only in this way, it will be possible to evaluate the predictive and prognostic characteristics of those novel promising biomarkers.
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Affiliation(s)
- Lien Van De Voorde
- Department of Radiation Oncology and Experimental Cancer Research, Ghent University Hospital, Ghent, Belgium
| | | | - Dirk Van Gestel
- Department of Radiation Oncology, Antwerp University Hospital, Antwerp, Belgium
| | - Marc Bracke
- Department of Radiation Oncology and Experimental Cancer Research, Ghent University Hospital, Ghent, Belgium
| | - Wilfried De Neve
- Department of Radiation Oncology and Experimental Cancer Research, Ghent University Hospital, Ghent, Belgium
| | - Joris Delanghe
- Department of Clinical Chemistry, Ghent University Hospital, Ghent, Belgium
| | - Marijn Speeckaert
- Department of Clinical Chemistry, Ghent University Hospital, Ghent, Belgium; Department of Internal Medicine, Ghent University Hospital, Ghent, Belgium.
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Lodde V, Modina SC, Franciosi F, Zuccari E, Tessaro I, Luciano AM. Localization of DNA methyltransferase-1 during oocyte differentiation, in vitro maturation and early embryonic development in cow. Eur J Histochem 2012; 53:e24. [PMID: 22073356 PMCID: PMC3167337 DOI: 10.4081/ejh.2009.e24] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2009] [Indexed: 12/31/2022] Open
Abstract
DNA methyltransferase-1 (Dnmt1) is involved in the maintenance of DNA methylation patterns and is crucial for normal mammalian development. The aim of the present study was to assess the localization of Dnmt1 in cow, during the latest phases of oocyte differentiation and during the early stages of segmentation. Dnmt1 expression and localization were assessed in oocytes according to the chromatin configuration, which in turn provides an important epigenetic mechanism for the control of global gene expression and represents a morphological marker of oocyte differentiation. We found that the initial chromatin condensation was accompanied by a slight increase in the level of global DNA methylation, as assessed by 5-methyl-cytosine immunostaining followed by laser scanning confocal microscopy analysis (LSCM). RT-PCR confirmed the presence of Dnmt1 transcripts throughout this phase of oocyte differentiation. Analogously, Dnmt1 immunodetection and LSCM indicated that the protein was always present and localized in the cytoplasm, regardless the chromatin configuration and the level of global DNA methylation. Moreover, our data indicate that while Dnmt1 is retained in the cytoplasm in metaphase II stage oocytes and zygotes, it enters the nuclei of 8–16 cell stage embryos. As suggested in mouse, the functional meaning of the presence of Dnmt1 in the bovine embryo nuclei could be the maintainement of the methylation pattern of imprinted genes. In conclusion, the present work provides useful elements for the study of Dnmt1 function during the late stage of oocyte differentiation, maturation and early embryonic development in mammals.
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Affiliation(s)
- V Lodde
- Division of Veterinary Anatomy and Histology, Department of Animal Sciences, Milan, Italy
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Wongtawan T, Taylor JE, Lawson KA, Wilmut I, Pennings S. Histone H4K20me3 and HP1α are late heterochromatin markers in development, but present in undifferentiated embryonic stem cells. J Cell Sci 2011; 124:1878-90. [DOI: 10.1242/jcs.080721] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We report here that the formation of heterochromatin in cell nuclei during mouse development is characterised by dynamic changes in the epigenetic modifications of histones. Our observations reveal that heterochromatin in mouse preimplantation embryos is in an immature state that lacks the constitutive heterochromatin markers histone H4 trimethyl Lys20 (H4K20me3) and chromobox homolog 5 (HP1α, also known as CBX5). Remarkably, these somatic heterochromatin hallmarks are not detectable – except in mural trophoblast – until mid-gestation, increasing in level during foetal development. Our results support a developmentally regulated connection between HP1α and H4K20me3. Whereas inner cell mass (ICM) and epiblast stain negative for H4K20me3 and HP1α, embryonic stem (ES) cell lines, by contrast, stain positive for these markers, indicating substantial chromatin divergence. We conclude that H4K20me3 and HP1α are late developmental epigenetic markers, and slow maturation of heterochromatin in tissues that develop from ICM is ectopically induced during ES cell derivation. Our findings suggest that H4K20me3 and HP1α are markers for cell type commitment that can be triggered by developmental or cell context, independently of the differentiation process.
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Affiliation(s)
- Tuempong Wongtawan
- MRC Centre for Regenerative Medicine, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
- Faculty of Veterinary Science, Mahidol University, Salaya Nakhonpathom 73170, Thailand
| | - Jane E. Taylor
- MRC Centre for Regenerative Medicine, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Kirstie A. Lawson
- Human Genetics Unit, Medical Research Council, Crewe Road, Edinburgh EH4 2XU, UK
| | - Ian Wilmut
- MRC Centre for Regenerative Medicine, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sari Pennings
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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Golding MC, Williamson GL, Stroud TK, Westhusin ME, Long CR. Examination of DNA methyltransferase expression in cloned embryos reveals an essential role for Dnmt1 in bovine development. Mol Reprod Dev 2011; 78:306-17. [PMID: 21480430 DOI: 10.1002/mrd.21306] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Accepted: 02/25/2011] [Indexed: 01/03/2023]
Abstract
In studies of somatic cell nuclear transfer (SCNT), the ability of factors within the oocyte to epigenetically reprogram transferred nuclei is essential for embryonic development of the clone to proceed. However, irregular patterns of X-chromosome inactivation, abnormal expression of imprinted genes, and genomic DNA hypermethylation are frequently observed in reconstructed embryos, suggesting abnormalities in this process. To better understand the epigenetic events underlying SCNT reprogramming, we sought to determine if the abnormal DNA methylation levels observed in cloned embryos result from a failure of the oocyte to properly reprogram transcription versus differential biochemical regulation of the DNA methyltransferase family of enzymes (DNMTs) between embryonic and somatic nuclei. To address this question, we conducted real-time quantitation of Dnmt transcripts in bovine preimplantation embryos generated though in vitro fertilization (IVF), parthenogenic activation, and SCNT. By the 8-cell stage, transcripts encoding Dnmt1 become significantly down-regulated in cloned embryos, likely in response to the state of genomic hypermethylation, while the de novo methyltransferases maintain an expression pattern indistinguishable from their IVF and parthenote counterparts. Depletion of embryonic/maternal Dnmt1 transcripts within IVF embryos using short-interfering RNAs, while able to lower genomic DNA methylation levels, resulted in developmental arrest at the 8/16-cell stage. In contrast, SCNT embryos derived from a stable, Dnmt1-depleted donor cell line develop to blastocyst stage, but failed to carry to term. Our results indicate an essential role for Dnmt1 during bovine preimplantation development, and suggest proper transcriptional reprogramming of this gene family in SCNT embryos.
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Affiliation(s)
- Michael C Golding
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA.
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Yamanaka KI, Sakatani M, Kubota K, Balboula AZ, Sawai K, Takahashi M. Effects of downregulating DNA methyltransferase 1 transcript by RNA interference on DNA methylation status of the satellite I region and in vitro development of bovine somatic cell nuclear transfer embryos. J Reprod Dev 2011; 57:393-402. [PMID: 21343670 DOI: 10.1262/jrd.10-181a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For the successful production of cloned animals by somatic cell nuclear transfer (NT), the epigenetic status of the differentiated donor cell is reversed to an embryonic totipotent status. However, in NT embryos, this process is aberrant, with genomic hypermethylation consistently observed. Here, we investigated the effects of silencing DNA methyltransferase 1 (DNMT1) mRNA by small interfering RNA (siRNA) on the DNA methylation status of the satellite I region and in vitro development of bovine NT embryos. First, the levels of DNMT1 expression were analyzed at 0, 24, 48, 72, 120 and 192 h after in vitro culture. Real-time PCR and western blotting analyses detected a significant decrease in DNMT1 mRNA in the siRNA-injected NT (siRNA-NT) group up to 72 h after in vitro culture. Next, the levels of DNA methylation of the satellite I region were analyzed at several time points after in vitro culture. The level of DNA methylation detected in siRNA-NT embryos was significantly less than those in NT embryos throughout in vitro development. Moreover, the developmental rate of embryos to blastocysts in the siRNA-NT group was significantly higher than that of NT embryos. Our data suggest that knockdown of DNMT1 mRNA in NT embryos can induce DNA demethylation, which may enhance reprogramming efficiency.
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Affiliation(s)
- Ken-ichi Yamanaka
- National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, Japan
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O'Meara CM, Murray JD, Mamo S, Gallagher E, Roche J, Lonergan P. Gene silencing in bovine zygotes: siRNA transfection versus microinjection. Reprod Fertil Dev 2011; 23:534-43. [DOI: 10.1071/rd10175] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 11/10/2010] [Indexed: 11/23/2022] Open
Abstract
The aim of this study was to compare gene silencing in bovine zygotes when small interfering RNAs (siRNAs) were introduced into bovine zygotes by microinjection or lipid-based transfection. In Experiment 1, E-cadherin siRNA was injected at 100 or 375 µM and compared with PBS-injected and non-injected controls. Embryos were then cultured in vitro for 7 days and periodically assessed for development. For transfection, zona-free zygotes were incubated in transfection medium with siRNA for 1 h at 39°C and then cultured to Day 7. Injection of PBS or 375 µM E-cadherin siRNA resulted in a decrease in the number of embryos reaching the 8-cell stage (51.5% and 45.5%) or the blastocyst stage (39.0 and 32.5%) compared with non-injected controls (62.9 and 45.0%, respectively; P < 0.05). Messenger RNA abundance was suppressed by 36 and 46% when siRNA targeting E-cadherin was injected at 100 and 375 µM, respectively, compared with controls (P < 0.05). Transfection with 100 nM E-cadherin siRNA decreased development to the 8-cell stage (20.3 versus 53.0%) and blastocyst stage (7.2 versus 18.2%) compared with controls (P < 0.05). Messenger RNA relative abundance was not different between controls (non-transfected or transfected with GAPDH or scrambled siRNA). However, transfection of zygotes with 100 and 200 nM E-cadherin siRNA led to a 72 and 38% reduction, respectively, in E-cadherin mRNA relative abundance in Day 7 blastocysts compared with controls (P < 0.05).
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Xiang G, Zhenkun F, Shuang C, Jie Z, Hua Z, Wei J, Da P, Dianjun L. Association of DNMT1 Gene Polymorphisms in Exons With Sporadic Infiltrating Ductal Breast Carcinoma Among Chinese Han Women in the Heilongjiang Province. Clin Breast Cancer 2010; 10:373-7. [DOI: 10.3816/cbc.2010.n.049] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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cDNA Cloning of Goat DNA Methyltransferase 1, Screening of shRNA Vectors and Influences to Development of Nuclear Transfer Embryos. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1671-2927(09)60187-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Lan J, Hua S, He X, Zhang Y. DNA methyltransferases and methyl-binding proteins of mammals. Acta Biochim Biophys Sin (Shanghai) 2010; 42:243-52. [PMID: 20383462 DOI: 10.1093/abbs/gmq015] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In mammals, DNA methylation, characterized by the transfer of the methyl group from S-adenosylmethionines to a base (mainly referred to cytosine), acts as a major epigenetic modification. In parallel to DNA sequences arrangement, modification of methylation to DNA sequences has far-reaching influence on biological functions and activities, for it involves controlling gene transcription, regulating chromatin structure, sustaining genome stability and integrity, maintaining parental imprinting and X-chromosome inactivation, suppressing homologous recombination as well as limiting transposable elements, during which DNA methyltransferases (DNMTs) and methyl-binding proteins play important roles. Their aberrance can give rise to dysregulation of gene expression, cell maltransformation and so on. Hence, it is necessary to gain a good understanding of these two important kinds of proteins, which will help to better investigate the epigenetic mechanisms and manipulate the modifications according to our will based on its reversibility. Here we briefly review our current understanding of DNMTs and methyl-binding proteins in mammals.
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Affiliation(s)
- Jie Lan
- Institution of biotechnology, Northwest Sci-Tech University of Agriculture and Forestry, Yangling, China.
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