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Shukla R, Mjoseng HK, Thomson JP, Kling S, Sproul D, Dunican DS, Ramsahoye B, Wongtawan T, Treindl F, Templin MF, Adams IR, Pennings S, Meehan RR. Activation of transcription factor circuity in 2i-induced ground state pluripotency is independent of repressive global epigenetic landscapes. Nucleic Acids Res 2020; 48:7748-7766. [PMID: 32585002 PMCID: PMC7641322 DOI: 10.1093/nar/gkaa529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 06/02/2020] [Accepted: 06/15/2020] [Indexed: 01/07/2023] Open
Abstract
Mouse embryonic stem cells (mESCs) cultured with MEK/ERK and GSK3β (2i) inhibitors transition to ground state pluripotency. Gene expression changes, redistribution of histone H3K27me3 profiles and global DNA hypomethylation are hallmarks of 2i exposure, but it is unclear whether epigenetic alterations are required to achieve and maintain ground state or occur as an outcome of 2i signal induced changes. Here we show that ESCs with three epitypes, WT, constitutively methylated, or hypomethylated, all undergo comparable morphological, protein expression and transcriptome changes independently of global alterations of DNA methylation levels or changes in H3K27me3 profiles. Dazl and Fkbp6 expression are induced by 2i in all three epitypes, despite exhibiting hypermethylated promoters in constitutively methylated ESCs. We identify a number of activated gene promoters that undergo 2i dependent loss of H3K27me3 in all three epitypes, however genetic and pharmaceutical inhibition experiments show that H3K27me3 is not required for their silencing in non-2i conditions. By separating and defining their contributions, our data suggest that repressive epigenetic systems play minor roles in mESC self-renewal and naïve ground state establishment by core sets of dominant pluripotency associated transcription factor networks, which operate independently from these epigenetic processes.
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Affiliation(s)
- Ruchi Shukla
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
- Newcastle University Centre for Cancer, Biosciences Institute, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK
| | - Heidi K Mjoseng
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - John P Thomson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Simon Kling
- NMI Natural and Medical Sciences Institute, Tübingen University, Reutlingen, Germany
| | - Duncan Sproul
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Donncha S Dunican
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Bernard Ramsahoye
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Tuempong Wongtawan
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Fridolin Treindl
- NMI Natural and Medical Sciences Institute, Tübingen University, Reutlingen, Germany
- Pharmaceutical Biotechnology, Tübingen University, Tübingen, Germany
| | - Markus F Templin
- NMI Natural and Medical Sciences Institute, Tübingen University, Reutlingen, Germany
- Pharmaceutical Biotechnology, Tübingen University, Tübingen, Germany
| | - Ian R Adams
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Sari Pennings
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Richard R Meehan
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, WGH, University of Edinburgh, Edinburgh EH4 2XU, UK
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Deng M, Zhang G, Cai Y, Liu Z, Zhang Y, Meng F, Wang F, Wan Y. DNA methylation dynamics during zygotic genome activation in goat. Theriogenology 2020; 156:144-154. [PMID: 32731098 DOI: 10.1016/j.theriogenology.2020.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022]
Abstract
DNA methylation is a crucial element in the epigenetic regulation of mammalian embryonic development. However, the subtle changes in DNA methylation differ in species, and, little information is known regarding the dynamics of DNA methylation at the single-base resolution in goat. In the present study, we studied the DNA methylation dynamics during goat zygotic genome activation (ZGA) at global and single-base resolution using immunostaining and reduced representation bisulfite sequencing, respectively. We showed that DNA methylation was decreased both at global and single-base resolution, and the expression of TET1 was increased while DNMT1 was decreased during ZGA in goat. We identified 51058 tiles of differential methylation regions (DMRs), which were enriched in the developmental process, the regulation of developmental process, AMPK signaling pathway, mTOR signaling pathway, autophagy, and lysosome, as revealed by GO and KEGG enrichment analysis. Furthermore, we found an association between the methylation level and the expression of imprinted genes (IGF2R, PEG3, and ZFP64), maternal genes (TRIM28, SETD1A, SIN3A, and NPM2), and zygotic genes (DUXA, IGF2BP1, WT1, and ZIM3), suggesting that DNA methylation is in the tight control of ZGA in goat by regulating the expression of the critical genes. Our data will help to understand the stochastic ZGA events to achieve better development of goat embryos in vitro and provide an excellent source for further ZGA studies.
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Affiliation(s)
- Mingtian Deng
- Jiangsu Livestock Embryo Engineering Laboratory, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Guomin Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yu Cai
- Jiangsu Livestock Embryo Engineering Laboratory, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zifei Liu
- 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
| | - Fanxing Meng
- National Experimental Teaching Demonstration Center of Animal Science, 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
| | - Yongjie Wan
- Jiangsu Livestock Embryo Engineering Laboratory, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
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Han C, Cui C, Xing X, Lu Z, Zhang J, Liu J, Zhang Y. Functions of intrinsic disorder in proteins involved in DNA demethylation during pre-implantation embryonic development. Int J Biol Macromol 2019; 136:962-979. [PMID: 31229544 DOI: 10.1016/j.ijbiomac.2019.06.143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 01/21/2023]
Abstract
DNA demethylation is involved in many biological processes during pre-implantation embryonic development in mammals. To date, the complicated mechanism of DNA demethylation is still not fully understood. Ten-eleven translocation family (TET3, TET1 and TET2), thymine DNA glycosylase (TDG) and DNA methyltransferase 1 (DNMT1) are considered the major protein enzymes of DNA demethylation in pre-implantation embryos. TET3, TET1, TET2, TDG, and DNMT1 contain abundant levels of intrinsically disordered protein regions (IDPRs), which contribute to increasing the functional diversity of proteins. Thus we tried to explore the complicated DNA demethylation in pre-implantation embryos from the intrinsic disorder perspective. These five biological macromolecules all have DNA demethylation-related functional domains. They can work together to fulfill DNA demethylation in pre-implantation embryos through complex protein-protein interaction networks. Intrinsic disorder analysis results showed these proteins were partial intrinsically disordered proteins. Many identifiable disorder-based DNA-binding sites, protein-binding sites and post-translational modification sites located in the intrinsically disordered regions, and DNA demethylation deficiency point mutations in the IDPRs could significantly change the local disorder propensity of these proteins. To the best of our knowledge, this work provides a new viewpoint for studying the mechanism of DNA methylation reprogramming during mammalian pre-implantation embryonic development.
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Affiliation(s)
- Chengquan Han
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Chenchen Cui
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Xupeng Xing
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Zhenzhen Lu
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jingcheng Zhang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jun Liu
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Yong Zhang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China.
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Oxidative stress in sperm affects the epigenetic reprogramming in early embryonic development. Epigenetics Chromatin 2018; 11:60. [PMID: 30333056 PMCID: PMC6192351 DOI: 10.1186/s13072-018-0224-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 09/17/2018] [Indexed: 12/27/2022] Open
Abstract
Background Reactive oxygen species (ROS)-induced oxidative stress is well known to play a major role in male infertility. Sperm are sensitive to ROS damaging effects because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. However, how oxidative DNA lesions in sperm affect early embryonic development remains elusive. Results Using cattle as model, we show that fertilization using sperm exposed to oxidative stress caused a major developmental arrest at the time of embryonic genome activation. The levels of DNA damage response did not directly correlate with the degree of developmental defects. The early cellular response for DNA damage, γH2AX, is already present at high levels in zygotes that progress normally in development and did not significantly increase at the paternal genome containing oxidative DNA lesions. Moreover, XRCC1, a factor implicated in the last step of base excision repair (BER) pathway, was recruited to the damaged paternal genome, indicating that the maternal BER machinery can repair these DNA lesions induced in sperm. Remarkably, the paternal genome with oxidative DNA lesions showed an impairment of zygotic active DNA demethylation, a process that previous studies linked to BER. Quantitative immunofluorescence analysis and ultrasensitive LC–MS-based measurements revealed that oxidative DNA lesions in sperm impair active DNA demethylation at paternal pronuclei, without affecting 5-hydroxymethylcytosine (5hmC), a 5-methylcytosine modification that has been implicated in paternal active DNA demethylation in mouse zygotes. Thus, other 5hmC-independent processes are implicated in active DNA demethylation in bovine embryos. The recruitment of XRCC1 to damaged paternal pronuclei indicates that oxidative DNA lesions drive BER to repair DNA at the expense of DNA demethylation. Finally, this study highlighted striking differences in DNA methylation dynamics between bovine and mouse zygotes that will facilitate the understanding of the dynamics of DNA methylation in early development. Conclusions The data demonstrate that oxidative stress in sperm has an impact not only on DNA integrity but also on the dynamics of epigenetic reprogramming, which may harm the paternal genetic and epigenetic contribution to the developing embryo and affect embryo development and embryo quality. Electronic supplementary material The online version of this article (10.1186/s13072-018-0224-y) contains supplementary material, which is available to authorized users.
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Han C, Deng R, Mao T, Luo Y, Wei B, Meng P, Zhao L, Zhang Q, Quan F, Liu J, Zhang Y. Overexpression of Tet3 in donor cells enhances goat somatic cell nuclear transfer efficiency. FEBS J 2018; 285:2708-2723. [PMID: 29791079 DOI: 10.1111/febs.14515] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/31/2018] [Accepted: 05/18/2018] [Indexed: 12/14/2022]
Abstract
Ten-eleven translocation 3 (TET3) mediates active DNA demethylation of paternal genomes during mouse embryonic development. However, the mechanism of DNA demethylation in goat embryos remains unknown. In addition, aberrant DNA methylation reprogramming prevalently occurs in embryos cloned by somatic cell nuclear transfer (SCNT). In this study, we reported that TET3 is a key factor in DNA demethylation in goat pre-implantation embryos. Knockdown of Tet3 hindered DNA demethylation at the two- to four-cell stage in goat embryos and decreased Nanog expression in blastocysts. Overexpression of Tet3 in somatic cells can initiate DNA demethylation, reduce 5-methylcytosine level, increase 5-hydroxymethylcytosine level and promote the expression of key pluripotency genes. After SCNT, overexpression of Tet3 in donor cells corrected abnormal DNA hypermethylation of cloned embryos and significantly enhanced in vitro and in vivo developmental rate (P < 0.05). We conclude that overexpression of Tet3 in donor cells significantly improves goat SCNT efficiency.
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Affiliation(s)
- Chengquan Han
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Ruizhi Deng
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Tingchao Mao
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yan Luo
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Biao Wei
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Peng Meng
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Lu Zhao
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Qing Zhang
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Fusheng Quan
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Jun Liu
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
| | - Yong Zhang
- Key Laboratory of Animal Biotechnology, College of Veterinary Medicine, Ministry of Agriculture, Northwest A&F University, Yangling, China
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Heras S, Smits K, De Schauwer C, Van Soom A. Dynamics of 5-methylcytosine and 5-hydroxymethylcytosine during pronuclear development in equine zygotes produced by ICSI. Epigenetics Chromatin 2017; 10:13. [PMID: 28331549 PMCID: PMC5353960 DOI: 10.1186/s13072-017-0120-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/08/2017] [Indexed: 01/12/2023] Open
Abstract
Background Global epigenetic reprogramming is considered to be essential during embryo development to establish totipotency. In the classic model first described in the mouse, the genome-wide DNA demethylation is asymmetric between the paternal and the maternal genome. The paternal genome undergoes ten-eleven translocation (TET)-mediated active DNA demethylation, which is completed before the end of the first cell cycle. Since TET enzymes oxidize 5-methylcytosine to 5-hydroxymethylcytosine, the latter is postulated to be an intermediate stage toward DNA demethylation. The maternal genome, on the other hand, is protected from active demethylation and undergoes replication-dependent DNA demethylation. However, several species do not show the asymmetric DNA demethylation process described in this classic model, since 5-methylcytosine and 5-hydroxymethylcytosine are present during the first cell cycle in both parental genomes. In this study, global changes in the levels of 5-methylcytosine and 5-hydroxymethylcytosine throughout pronuclear development in equine zygotes produced in vitro were assessed using immunofluorescent staining. Results We were able to show that 5-methylcytosine and 5-hydroxymethylcytosine both were explicitly present throughout pronuclear development, with similar intensity levels in both parental genomes, in equine zygotes produced by ICSI. The localization patterns of 5-methylcytosine and 5-hydroxymethylcytosine, however, were different, with 5-hydroxymethylcytosine homogeneously distributed in the DNA, while 5-methylcytosine tended to be clustered in certain regions. Fluorescence quantification showed increased 5-methylcytosine levels in the maternal genome from PN1 to PN2, while no differences were found in PN3 and PN4. No differences were observed in the paternal genome. Normalized levels of 5-hydroxymethylcytosine were preserved throughout all pronuclear stages in both parental genomes. Conclusions In conclusion, the horse does not seem to follow the classic model of asymmetric demethylation as no evidence of global DNA demethylation of the paternal pronucleus during the first cell cycle was demonstrated. Instead, both parental genomes displayed sustained and similar levels of methylation and hydroxymethylation throughout pronuclear development.
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Affiliation(s)
- Sonia Heras
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Katrien Smits
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Catharina De Schauwer
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Ann Van Soom
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
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Xu YN, Cui XS, Sun SC, Jin YX, Kim NH. Cross species fertilization and development investigated by cat sperm injection into mouse oocytes. ACTA ACUST UNITED AC 2011; 315:349-57. [DOI: 10.1002/jez.682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 01/19/2011] [Accepted: 02/21/2011] [Indexed: 11/06/2022]
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Xu YN, Cui XS, Tae JC, Jin YX, Kim NH. DNA synthesis and epigenetic modification during mouse oocyte fertilization by human or hamster sperm injection. J Assist Reprod Genet 2010; 28:325-33. [PMID: 21107900 DOI: 10.1007/s10815-010-9509-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 11/08/2010] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To evaluate DNA synthesis and epigenetic modification in mouse oocytes during the first cell cycle following the injection of human or hamster sperm. METHODS Mouse oocytes following the injection of human and hamster sperm and cultured in M16 medium. RESULTS Male and female pronucleus formation, DNA synthesis, histone protein modification, and heterochromatin formation were similar in mouse oocytes injected with human or hamster sperm. However, DNA methylation patterns were altered in mouse oocytes following human sperm injection. Immunocytochemical staining with a histone H3-MeK9 antibody revealed that human and hamster sperm chromatin associated normally with female mouse chromatin, then entered into the metaphase and formed normal, two-cell stage embryos. CONCLUSIONS Although differences in epigenetic modification of DNA were observed, fertilization and cleavage occurred in a species non-specific manner in mouse oocytes.
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Affiliation(s)
- Yong-Nan Xu
- Department of Animal Sciences, Chungbuk National University, Gaesin-dong, Cheongju, Chungbuk, 361-763, South Korea
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Abdalla H, Yoshizawa Y, Hochi S. Active demethylation of paternal genome in mammalian zygotes. J Reprod Dev 2009; 55:356-60. [PMID: 19721335 DOI: 10.1262/jrd.20234] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epigenetic reprogramming in early preimplantation embryos, that refers to erasing and remodeling epigenetic marks such as DNA methylation, is essential for differentiation and development. In many species, paternal genome is subjected to genome-wide active demethylation before the DNA replication commences, while maternal genome maintains its methylation status until being demethylated passively during the subsequent cleavage divisions. The purpose of this manuscript was to review the available knowledge about the paternal genome active demethylation process concerning the possible mechanisms, species variation and the factors affecting the active demethylation dynamics such as in vitro protocols for production of pronuclear-stage zygotes. Better understanding the mechanisms by which the epigenetic reprogramming is occurred may contribute to clarify the biological significance of this process.
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Affiliation(s)
- Hany Abdalla
- Interdisciplinary Graduate School of Science and Technology, Shinshu University, Nagano, Japan
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ABDALLA H, HIRABAYASHI M, HOCHI S. Demethylation Dynamics of the Paternal Genome in Pronuclear-Stage Bovine Zygotes Produced by In Vitro Fertilization and Ooplasmic Injection of Freeze-Thawed or Freeze-Dried Spermatozoa. J Reprod Dev 2009; 55:433-9. [DOI: 10.1262/jrd.20229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hany ABDALLA
- Interdisciplinary Graduate School of Science and Technology, Shinshu University
| | - Masumi HIRABAYASHI
- National Institute for Physiological Sciences
- The Graduate University of Advanced Studies
| | - Shinichi HOCHI
- Interdisciplinary Graduate School of Science and Technology, Shinshu University
- Faculty of Textile Science and Technology, Shinshu University
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Hou J, Liu L, Zhang J, Cui XH, Yan FX, Guan H, Chen YF, An XR. Epigenetic modification of histone 3 at lysine 9 in sheep zygotes and its relationship with DNA methylation. BMC DEVELOPMENTAL BIOLOGY 2008; 8:60. [PMID: 18507869 PMCID: PMC2430946 DOI: 10.1186/1471-213x-8-60] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 05/29/2008] [Indexed: 12/04/2022]
Abstract
Background Previous studies indicated that, unlike mouse zygotes, sheep zygotes lacked the paternal DNA demethylation event. Another epigenetic mark, histone modification, especially at lysine 9 of histone 3 (H3K9), has been suggested to be mechanically linked to DNA methylation. In mouse zygotes, the absence of methylated H3K9 from the paternal pronucleus has been thought to attribute to the paternal DNA demethylation. Results By using the immunofluorescence staining approach, we show that, despite the difference in DNA methylation, modification of H3K9 is similar between the sheep and mouse zygotes. In both species, H3K9 is hyperacetylated or hypomethylated in paternal pronucleus relative to maternal pronucleus. In fact, sheep zygotes can also undergo paternal DNA demethylation, although to a less extent than the mouse. Further examinations of individual zygotes by double immunostaining revealed that, the paternal levels of DNA methylation were not closely associated with that of H3K9 acetylation or tri-methylation. Treatment of either 5-azacytidine or Trichostatin A did not induce a significant decrease of paternal DNA methylation levels. Conclusion Our results suggest that in sheep lower DNA demethylation of paternal genomes is not due to the H3K9 modification and the methylated DNA sustaining in paternal pronucleus does not come from DNA de novo methylation.
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Affiliation(s)
- Jian Hou
- State Key Laboratory for Agrobiotechnology, College of Biological Science, China Agricultural University, Beijing 100094, PR China.
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Liu L, Hou J, Lei T, Bai J, Guan H, An X. Aberrant DNA methylation in cloned ovine embryos. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11434-008-0130-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fulka H, St John JC, Fulka J, Hozák P. Chromatin in early mammalian embryos: achieving the pluripotent state. Differentiation 2007; 76:3-14. [PMID: 18093226 DOI: 10.1111/j.1432-0436.2007.00247.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gametes of both sexes (sperm and oocyte) are highly specialized and differentiated but within a very short time period post-fertilization the embryonic genome, produced by the combination of the two highly specialized parental genomes, is completely converted into a totipotent state. As a result, the one-cell-stage embryo can give rise to all cell types of all three embryonic layers, including the gametes. Thus, it is evident that extensive and efficient reprogramming steps occur soon after fertilization and also probably during early embryogenesis to reverse completely the differentiated state of the gamete and to achieve toti- or later on pluripotency of embryonic cells. However, after the embryo reaches the blastocyst stage, the first two distinct cell lineages can be clearly distinguished--the trophectoderm and the inner cells mass. The de-differentiation of gametes after fertilization, as well as the differentiation that is associated with the formation of blastocysts, are accompanied by changes in the state and properties of chromatin in individual embryonic nuclei at both the whole genome level as well as at the level of individual genes. In this contribution, we focus mainly on those events that take place soon after fertilization and during early embryogenesis in mammals. We will discuss the changes in DNA methylation and covalent histone modifications that were shown to be highly dynamic during this period; moreover, it has also been documented that abnormalities in these processes have a devastating impact on the developmental ability of embryos. Special attention will be paid to somatic cell nuclear transfer as it has been shown that the aberrant and inefficient reprogramming may be responsible for compromised development of cloned embryos.
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Affiliation(s)
- Helena Fulka
- Institute of Animal Science, Prátelství 815, 104 00 Prague 10, Czech Republic
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Hou J, Liu L, Lei T, Cui X, An X, Chen Y. Genomic DNA methylation patterns in bovine preimplantation embryos derived from in vitro fertilization. ACTA ACUST UNITED AC 2007; 50:56-61. [PMID: 17393083 DOI: 10.1007/s11427-007-0003-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 04/25/2006] [Indexed: 11/29/2022]
Abstract
By using the approach of immunofluorescence staining with an antibody against 5-methylcytosine (5MeC), the present study detected the DNA methylation patterns of bovine zygotes and preimplantation embryos derived from oocyte in vitro maturation (IVM), in vitro fertilization (IVF) and embryo in vitro culture (IVC). The results showed that: a) paternal-specific demethylation occurred in 61.5% of the examined zygotes, while 34.6% of them showed no demethylation; b) decreased methylation level was observed after the 8-cell stage and persisted through the morula stage, however methylation levels were different between blastomeres within the same embryos; c) at the blastocyst stage, the methylation level was very low in inner cell mass, but high in trophectoderm cells. The present study suggests, at least partly, that IVM/IVF/IVC may have effects on DNA methylation reprogramming of bovine zygotes and early embryos.
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Affiliation(s)
- Jian Hou
- State Key Laboratory for Agrobiotechnology and Department of Animal Physiology, College of Biological Science, China Agricultural University, Beijing, 100094, China
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