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Weinberg-Shukron A, Youngson NA, Ferguson-Smith AC, Edwards CA. Epigenetic control and genomic imprinting dynamics of the Dlk1-Dio3 domain. Front Cell Dev Biol 2023; 11:1328806. [PMID: 38155837 PMCID: PMC10754522 DOI: 10.3389/fcell.2023.1328806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023] Open
Abstract
Genomic imprinting is an epigenetic process whereby genes are monoallelically expressed in a parent-of-origin-specific manner. Imprinted genes are frequently found clustered in the genome, likely illustrating their need for both shared regulatory control and functional inter-dependence. The Dlk1-Dio3 domain is one of the largest imprinted clusters. Genes in this region are involved in development, behavior, and postnatal metabolism: failure to correctly regulate the domain leads to Kagami-Ogata or Temple syndromes in humans. The region contains many of the hallmarks of other imprinted domains, such as long non-coding RNAs and parental origin-specific CTCF binding. Recent studies have shown that the Dlk1-Dio3 domain is exquisitely regulated via a bipartite imprinting control region (ICR) which functions differently on the two parental chromosomes to establish monoallelic expression. Furthermore, the Dlk1 gene displays a selective absence of imprinting in the neurogenic niche, illustrating the need for precise dosage modulation of this domain in different tissues. Here, we discuss the following: how differential epigenetic marks laid down in the gametes cause a cascade of events that leads to imprinting in the region, how this mechanism is selectively switched off in the neurogenic niche, and why studying this imprinted region has added a layer of sophistication to how we think about the hierarchical epigenetic control of genome function.
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Affiliation(s)
| | - Neil A. Youngson
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | | | - Carol A. Edwards
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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Matsuzaki H, Takahashi T, Kuramochi D, Hirakawa K, Tanimoto K. Five nucleotides found in RCTG motifs are essential for post-fertilization methylation imprinting of the H19 ICR in YAC transgenic mice. Nucleic Acids Res 2023; 51:7236-7253. [PMID: 37334871 PMCID: PMC10415150 DOI: 10.1093/nar/gkad516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 06/02/2023] [Indexed: 06/21/2023] Open
Abstract
Genomic imprinting at the mouse Igf2/H19 locus is controlled by the H19 ICR, within which paternal allele-specific DNA methylation originating in sperm is maintained throughout development in offspring. We previously found that a 2.9 kb transgenic H19 ICR fragment in mice can be methylated de novo after fertilization only when paternally inherited, despite its unmethylated state in sperm. When the 118 bp sequence responsible for this methylation in transgenic mice was deleted from the endogenous H19 ICR, the methylation level of its paternal allele was significantly reduced after fertilization, suggesting the activity involving this 118 bp sequence is required for methylation maintenance at the endogenous locus. Here, we determined protein binding to the 118 bp sequence using an in vitro binding assay and inferred the binding motif to be RCTG by using a series of mutant competitors. Furthermore, we generated H19 ICR transgenic mice with a 5-bp substitution mutation that disrupts the RCTG motifs within the 118 bp sequence, and observed loss of methylation from the paternally inherited transgene. These results indicate that imprinted methylation of the H19 ICR established de novo during the post-fertilization period involves binding of specific factors to distinct sequence motifs within the 118 bp sequence.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Takuya Takahashi
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Daichi Kuramochi
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Katsuhiko Hirakawa
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
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Matsuzaki H, Sugihara S, Tanimoto K. The transgenic IG-DMR sequence of the mouse Dlk1-Dio3 domain acquired imprinted DNA methylation during the post-fertilization period. Epigenetics Chromatin 2023; 16:7. [PMID: 36797774 PMCID: PMC9936741 DOI: 10.1186/s13072-023-00482-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/07/2023] [Indexed: 02/18/2023] Open
Abstract
BACKGROUND Allele-specific methylation of the imprinting control region (ICR) is the molecular basis for the genomic imprinting phenomenon that is unique to placental mammals. We previously showed that the ICR at the mouse H19 gene locus (H19 ICR) was unexpectedly established after fertilization and not during spermatogenesis in transgenic mice (TgM), and that the same activity was essential for the maintenance of paternal methylation of the H19 ICR at the endogenous locus in pre-implantation embryos. To examine the universality of post-fertilization imprinted methylation across animal species or imprinted loci, we generated TgM with two additional sequences. RESULTS The rat H19 ICR, which is very similar in structure to the mouse H19 ICR, unexpectedly did not acquire imprinted methylation even after fertilization, suggesting a lack of essential sequences in the transgene fragment. In contrast, the mouse IG-DMR, the methylation of which is acquired during spermatogenesis at the endogenous locus, did not acquire methylation in the sperm of TgM, yet became highly methylated in blastocysts after fertilization, but only when the transgene was paternally inherited. Since these two sequences were evaluated at the same genomic site by employing the transgene co-placement strategy, it is likely that the phenotype reflects the intrinsic activity of these fragments rather than position-effect variegation. CONCLUSIONS Our results suggested that post-fertilization imprinted methylation is a versatile mechanism for protecting paternal imprinted methylation from reprogramming during the pre-implantation period.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan
| | - Shokichi Sugihara
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan.
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Chen H, Zhang L, Yue F, Cui C, Li Y, Zhang Q, Liang L, Meng L, Zhang C. Effects of assisted reproductive technology on gene expression in heart and spleen tissues of adult offspring mouse. Front Endocrinol (Lausanne) 2023; 14:1035161. [PMID: 37065763 PMCID: PMC10098333 DOI: 10.3389/fendo.2023.1035161] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 03/10/2023] [Indexed: 04/18/2023] Open
Abstract
OBJECTIVES Assisted reproductive technology (ART) is an important part of reproductive medicine, whose possible effects on offspring's health have drawn widespread attention in recent years. However, relevant studies are limited to postnatal short-term follow-up and lack of diverse sample sources analysis other than blood. METHODS In this study, a mouse model was used to explore the effects of ART on fetal development and gene expression in the organs of offspring in the adulthood using next-generation sequencing. The sequencing results were then analyzed. RESULTS The results showed that it caused abnormal expression in 1060 genes and 179 genes in the heart and spleen, respectively. Differentially expressed genes (DEGs) in the heart are mainly enriched in RNA synthesis and processing, and the cardiovascular system development also shows enrichment. STRING analysis identified Ccl2, Ptgs2, Rock1, Mapk14, Agt, and Wnt5a as the core interacting factors. DEGs in the spleen are significantly enriched in anti-infection and immune responses, which include the core factors Fos, Jun and Il1r2. Further exploration revealed the abnormal expression of 42 and 5 epigenetic modifiers in the heart and spleen, respectively. The expression of the imprinted genes Dhcr7, Igf2, Mest and Smoc1 decreased in the hearts of ART offspring, and the DNA methylation levels of Igf2- and Mest-imprinting control regions (ICRs) increased abnormally. CONCLUSION In the mouse model, ART can interfere with the gene expression pattern in the heart and spleen of the adult offspring and that these changes are related to the aberrant expression of epigenetic regulators.
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Affiliation(s)
- Huanhuan Chen
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Lei Zhang
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Feng Yue
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Chenchen Cui
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Yan Li
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Qingwen Zhang
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Linlin Liang
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
| | - Li Meng
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
- *Correspondence: Li Meng, ; Cuilian Zhang,
| | - Cuilian Zhang
- Reproductive Medicine Center, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital of Henan University, Zhengzhou, Henan, China
- Henan Joint International Research Laboratory of Reproductive Bioengineering, Zhengzhou, Henan, China
- *Correspondence: Li Meng, ; Cuilian Zhang,
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Matsuzaki H, Miyajima Y, Fukamizu A, Tanimoto K. Orientation of mouse H19 ICR affects imprinted H19 gene expression through promoter methylation-dependent and -independent mechanisms. Commun Biol 2021; 4:1410. [PMID: 34921234 PMCID: PMC8683476 DOI: 10.1038/s42003-021-02939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/30/2021] [Indexed: 11/19/2022] Open
Abstract
The mouse Igf2/H19 locus is regulated by genomic imprinting, in which the paternally methylated H19 imprinting control region (ICR) plays a critical role in mono-allelic expression of the genes in the locus. Although the maternal allele-specific insulator activity of the H19 ICR in regulating imprinted Igf2 expression has been well established, the detailed mechanism by which the H19 ICR controls mono-allelic H19 gene expression has not been fully elucidated. In this study, we evaluated the effect of H19 ICR orientation on imprinting regulation in mutant mice in which the H19 ICR sequence was inverted at the endogenous locus. When the inverted-ICR allele was paternally inherited, the methylation level of the H19 promoter was decreased and the H19 gene was derepressed, suggesting that methylation of the H19 promoter is essential for complete repression of H19 gene expression. Unexpectedly, when the inverted allele was maternally inherited, the expression level of the H19 gene was lower than that of the WT allele, even though the H19 promoter remained fully hypomethylated. These observations suggested that the polarity of the H19 ICR is involved in controlling imprinted H19 gene expression on each parental allele, dependent or independent on DNA methylation of the H19 promoter.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan.
| | - Yu Miyajima
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Akiyoshi Fukamizu
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
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Santini L, Halbritter F, Titz-Teixeira F, Suzuki T, Asami M, Ma X, Ramesmayer J, Lackner A, Warr N, Pauler F, Hippenmeyer S, Laue E, Farlik M, Bock C, Beyer A, Perry ACF, Leeb M. Genomic imprinting in mouse blastocysts is predominantly associated with H3K27me3. Nat Commun 2021; 12:3804. [PMID: 34155196 PMCID: PMC8217501 DOI: 10.1038/s41467-021-23510-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 04/30/2021] [Indexed: 02/06/2023] Open
Abstract
In mammalian genomes, differentially methylated regions (DMRs) and histone marks including trimethylation of histone 3 lysine 27 (H3K27me3) at imprinted genes are asymmetrically inherited to control parentally-biased gene expression. However, neither parent-of-origin-specific transcription nor imprints have been comprehensively mapped at the blastocyst stage of preimplantation development. Here, we address this by integrating transcriptomic and epigenomic approaches in mouse preimplantation embryos. We find that seventy-one genes exhibit previously unreported parent-of-origin-specific expression in blastocysts (nBiX: novel blastocyst-imprinted expressed). Uniparental expression of nBiX genes disappears soon after implantation. Micro-whole-genome bisulfite sequencing (µWGBS) of individual uniparental blastocysts detects 859 DMRs. We further find that 16% of nBiX genes are associated with a DMR, whereas most are associated with parentally-biased H3K27me3, suggesting a role for Polycomb-mediated imprinting in blastocysts. nBiX genes are clustered: five clusters contained at least one published imprinted gene, and five clusters exclusively contained nBiX genes. These data suggest that early development undergoes a complex program of stage-specific imprinting involving different tiers of regulation. In most mammals, imprinted genes contain epigenetic marks that differ in each parental genome and control their parent-of-origin-specific expression. Here, the authors map imprinted genes in mouse preimplantation embryos and find that imprinted gene expression in blastocysts is mainly dependent on Polycomb-mediated H3K27me3-associated gene silencing.
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Affiliation(s)
- Laura Santini
- Max Perutz Laboratories Vienna, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Florian Halbritter
- St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Fabian Titz-Teixeira
- Cologne Excellence Cluster Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Toru Suzuki
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Maki Asami
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Xiaoyan Ma
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Julia Ramesmayer
- Max Perutz Laboratories Vienna, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Andreas Lackner
- Max Perutz Laboratories Vienna, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Nick Warr
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell, UK
| | - Florian Pauler
- Institute for Science and Technology Austria, Klosterneuburg, Austria
| | - Simon Hippenmeyer
- Institute for Science and Technology Austria, Klosterneuburg, Austria
| | - Ernest Laue
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Matthias Farlik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.,Institute of Artificial Intelligence and Decision Support, Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Andreas Beyer
- Cologne Excellence Cluster Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Anthony C F Perry
- Laboratory of Mammalian Molecular Embryology, Department of Biology and Biochemistry, University of Bath, Bath, UK.
| | - Martin Leeb
- Max Perutz Laboratories Vienna, University of Vienna, Vienna Biocenter, Vienna, Austria.
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Hirakawa K, Matsuzaki H, Tanimoto K. Transient establishment of imprinted DNA methylation of transgenic human IC1 sequence in mouse during the preimplantation period. Hum Mol Genet 2020; 29:3646-3661. [PMID: 33258474 DOI: 10.1093/hmg/ddaa253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/14/2020] [Accepted: 11/26/2020] [Indexed: 01/31/2023] Open
Abstract
Monoallelic gene expression at the Igf2/H19 locus is controlled by paternal allele-specific DNA methylation of the imprinting control region (H19 ICR) that is established during spermatogenesis. We demonstrated that the H19 ICR fragment in transgenic mice acquires allele-specific methylation only after fertilization, which is essential for maintaining its allelic methylation during early embryogenesis. We identified a DNA element required for establishing postfertilization methylation within a 118 bp (m118) region. A previously generated knock-in mouse whose endogenous H19 ICR was substituted with the human H19 ICR (hIC1; 4.8 kb) sequence revealed that the hIC1 sequence was partially methylated in sperm, although this methylation was lost by the blastocyst stage, which we assume is due to a lack of an m118-equivalent sequence in the hIC1 transgene. To identify a cis sequence involved in postfertilization methylation within the hIC1 region, we generated three transgenic mouse lines (TgM): one carrying an 8.8 kb hIC1 sequence joined to m118 (hIC1+m118), one with the 8.8 kb hIC1 and one with the 5.8 kb hIC1 sequence joined to m118 (hIC1-3'+m118). We found that the hIC1-3' region was resistant to de novo DNA methylation throughout development. In contrast, the 5' portion of the hIC1 (hIC1-5') in both hIC1+m118 and hIC1 TgM were preferentially methylated on the paternal allele only during preimplantation. As DNA methylation levels were higher in hIC1+m118, the m118 sequence could also induce imprinted methylation of the human sequence. Most importantly, the hIC1-5' sequence appears to possess an activity equivalent to that of m118.
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Affiliation(s)
- Katsuhiko Hirakawa
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
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Ma X, Cen S, Wang L, Zhang C, Wu L, Tian X, Wu Q, Li X, Wang X. Genome-wide identification and comparison of differentially expressed profiles of miRNAs and lncRNAs with associated ceRNA networks in the gonads of Chinese soft-shelled turtle, Pelodiscus sinensis. BMC Genomics 2020; 21:443. [PMID: 32600250 PMCID: PMC7322844 DOI: 10.1186/s12864-020-06826-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 06/15/2020] [Indexed: 12/16/2022] Open
Abstract
Background The gonad is the major factor affecting animal reproduction. The regulatory mechanism of the expression of protein-coding genes involved in reproduction still remains to be elucidated. Increasing evidence has shown that ncRNAs play key regulatory roles in gene expression in many life processes. The roles of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in reproduction have been investigated in some species. However, the regulatory patterns of miRNA and lncRNA in the sex biased expression of protein coding genes remains to be elucidated. In this study, we performed an integrated analysis of miRNA, messenger RNA (mRNA), and lncRNA expression profiles to explore their regulatory patterns in the female ovary and male testis of Pelodiscus sinensis. Results We identified 10,446 mature miRNAs, 20,414 mRNAs and 28,500 lncRNAs in the ovaries and testes, and 633 miRNAs, 11,319 mRNAs, and 10,495 lncRNAs showed differential expression. A total of 2814 target genes were identified for miRNAs. The predicted target genes of these differentially expressed (DE) miRNAs and lncRNAs included abundant genes related to reproductive regulation. Furthermore, we found that 189 DEmiRNAs and 5408 DElncRNAs showed sex-specific expression. Of these, 3 DEmiRNAs and 917 DElncRNAs were testis-specific, and 186 DEmiRNAs and 4491 DElncRNAs were ovary-specific. We further constructed complete endogenous lncRNA-miRNA-mRNA networks using bioinformatics, including 103 DEmiRNAs, 636 DEmRNAs, and 1622 DElncRNAs. The target genes for the differentially expressed miRNAs and lncRNAs included abundant genes involved in gonadal development, including Wt1, Creb3l2, Gata4, Wnt2, Nr5a1, Hsd17, Igf2r, H2afz, Lin52, Trim71, Zar1, and Jazf1. Conclusions In animals, miRNA and lncRNA as master regulators regulate reproductive processes by controlling the expression of mRNAs. Considering their importance, the identified miRNAs, lncRNAs, and their targets in P. sinensis might be useful for studying the molecular processes involved in sexual reproduction and genome editing to produce higher quality aquaculture animals. A thorough understanding of ncRNA-based cellular regulatory networks will aid in the improvement of P. sinensis reproductive traits for aquaculture.
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Affiliation(s)
- Xiao Ma
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China.,College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, 410128, People's Republic of China
| | - Shuangshuang Cen
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China
| | - Luming Wang
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China
| | - Chao Zhang
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China
| | - Limin Wu
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China
| | - Xue Tian
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China
| | - Qisheng Wu
- Fisheries Research Institute of Fujian, Xiamen, Fujian, 361000, People's Republic of China
| | - Xuejun Li
- College of Fisheries, Henan Normal University, Xinxiang, Henan, 453007, People's Republic of China.
| | - Xiaoqing Wang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, 410128, People's Republic of China.
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9
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Matsuzaki H, Kuramochi D, Okamura E, Hirakawa K, Ushiki A, Tanimoto K. Recapitulation of gametic DNA methylation and its post-fertilization maintenance with reassembled DNA elements at the mouse Igf2/H19 locus. Epigenetics Chromatin 2020; 13:2. [PMID: 31937365 PMCID: PMC6958606 DOI: 10.1186/s13072-019-0326-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/30/2019] [Indexed: 12/23/2022] Open
Abstract
Background Paternal allele-specific DNA methylation of the H19 imprinting control region (ICR) regulates imprinted expression of the Igf2/H19 genes. The molecular mechanism by which differential methylation of the H19 ICR is established during gametogenesis and maintained after fertilization, however, is not fully understood. We previously showed that a 2.9-kb H19 ICR fragment in transgenic mice was differentially methylated only after fertilization, demonstrating that two separable events, gametic and post-fertilization methylation, occur at the H19 ICR. We then determined that CTCF/Sox-Oct motifs and the 478-bp sequence of the H19 ICR are essential for maintaining its maternal hypomethylation status and for acquisition of paternal methylation, respectively, during the post-fertilization period. Results Using a series of 5′-truncated H19 ICR transgenes to dissect the 478-bp sequence, we identified a 118-bp region required for post-fertilization methylation activity. Deletion of the sequence from the paternal endogenous H19 ICR caused loss of methylation after fertilization, indicating that methylation activity of the sequence is required to protect endogenous H19 ICR from genome-wide reprogramming. We then reconstructed a synthetic DNA fragment in which the CTCF binding sites, Sox-Oct motifs, as well as the 118-bp sequence, were inserted into lambda DNA, and used it to replace the endogenous H19 ICR. The fragment was methylated during spermatogenesis; moreover, its allele-specific methylation status was faithfully maintained after fertilization, and imprinted expression of the both Igf2 and H19 genes was recapitulated. Conclusions Our results identified a 118-bp region within the H19 ICR that is required for de novo DNA methylation of the paternally inherited H19 ICR during pre-implantation period. A lambda DNA-based artificial fragment that contains the 118-bp sequence, in addition to the previously identified cis elements, could fully replace the function of the H19 ICR in the mouse genome.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan
| | - Daichi Kuramochi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Eiichi Okamura
- Department of Stem Cells and Human Disease Models, Research Center for Animal Life Science, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Katsuhiko Hirakawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Aki Ushiki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan.
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10
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Farhadova S, Gomez-Velazquez M, Feil R. Stability and Lability of Parental Methylation Imprints in Development and Disease. Genes (Basel) 2019; 10:genes10120999. [PMID: 31810366 PMCID: PMC6947649 DOI: 10.3390/genes10120999] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 02/06/2023] Open
Abstract
DNA methylation plays essential roles in mammals. Of particular interest are parental methylation marks that originate from the oocyte or the sperm, and bring about mono-allelic gene expression at defined chromosomal regions. The remarkable somatic stability of these parental imprints in the pre-implantation embryo—where they resist global waves of DNA demethylation—is not fully understood despite the importance of this phenomenon. After implantation, some methylation imprints persist in the placenta only, a tissue in which many genes are imprinted. Again here, the underlying epigenetic mechanisms are not clear. Mouse studies have pinpointed the involvement of transcription factors, covalent histone modifications, and histone variants. These and other features linked to the stability of methylation imprints are instructive as concerns their conservation in humans, in which different congenital disorders are caused by perturbed parental imprints. Here, we discuss DNA and histone methylation imprints, and why unravelling maintenance mechanisms is important for understanding imprinting disorders in humans.
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11
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Miki Y, Tsukamoto S, Minami N. How does the promoter of an oocyte-specific gene function in male germ cells? J Reprod Dev 2018; 64:463-468. [PMID: 30197401 PMCID: PMC6305850 DOI: 10.1262/jrd.2018-060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studying gene expression in germ cells is useful for elucidating mechanisms of transcriptional regulation, because different genes are activated in male and female germ cells. The promoter regions of an oocyte-specific gene, Oog1, have been characterized. Driving the expression of green fluorescent protein with these different promoter regions provided us with critical information on the regulation of gene expression. The 3.9 kb long promoter functions in both male and female germ cells in transgenic mice. What is the cause of this sexually dimorphic expression? There may be important factors within and perhaps also outside this 3.9 kb promoter region that are required to maintain proper sex-specific gene expression.
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Affiliation(s)
- Yuka Miki
- Laboratory of Reproductive Biology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Satoshi Tsukamoto
- Laboratory Animal and Genome Sciences Section, National Institute for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Naojiro Minami
- Laboratory of Reproductive Biology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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12
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Matsuzaki H, Okamura E, Kuramochi D, Ushiki A, Hirakawa K, Fukamizu A, Tanimoto K. Synthetic DNA fragments bearing ICR cis elements become differentially methylated and recapitulate genomic imprinting in transgenic mice. Epigenetics Chromatin 2018; 11:36. [PMID: 29958543 PMCID: PMC6027785 DOI: 10.1186/s13072-018-0207-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/01/2018] [Indexed: 11/24/2022] Open
Abstract
Background Genomic imprinting is governed by allele-specific DNA methylation at imprinting control regions (ICRs), and the mechanism controlling its differential methylation establishment during gametogenesis has been a subject of intensive research interest. However, recent studies have reported that gamete methylation is not restricted at the ICRs, thus highlighting the significance of ICR methylation maintenance during the preimplantation period where genome-wide epigenetic reprogramming takes place. Using transgenic mice (TgM), we previously demonstrated that the H19 ICR possesses autonomous activity to acquire paternal-allele-specific DNA methylation after fertilization. Furthermore, this activity is indispensable for the maintenance of imprinted methylation at the endogenous H19 ICR during the preimplantation period. In addition, we showed that a specific 5′ fragment of the H19 ICR is required for its paternal methylation after fertilization, while CTCF and Sox-Oct motifs are essential for its maternal protection from undesirable methylation after implantation. Results To ask whether specific cis elements are sufficient to reconstitute imprinted methylation status, we employed a TgM co-placement strategy for facilitating detection of postfertilization methylation activity and precise comparison of test sequences. Bacteriophage lambda DNA becomes highly methylated regardless of its parental origin and thus can be used as a neutral sequence bearing no inclination for differential DNA methylation. We previously showed that insertion of only CTCF and Sox-Oct binding motifs from the H19 ICR into a lambda DNA (LCb) decreased its methylation level after both paternal and maternal transmission. We therefore appended a 478-bp 5′ sequence from the H19 ICR into the LCb fragment and found that it acquired paternal-allele-specific methylation, the dynamics of which was identical to that of the H19 ICR, in TgM. Crucially, transgene expression also became imprinted. Although there are potential binding sites for ZFP57 (a candidate protein thought to control the methylation imprint) in the larger H19 ICR, they are not found in the 478-bp fragment, rendering the role of ZFP57 in postfertilization H19 ICR methylation a still open question. Conclusions Our results demonstrate that a differentially methylated region can be reconstituted by combining the activities of specific imprinting elements and that these elements together determine the activity of a genomically imprinted region in vivo. Electronic supplementary material The online version of this article (10.1186/s13072-018-0207-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Eiichi Okamura
- Graduate School of Biomedical Sciences, Tokushima University, Tokushima, 770-8503, Japan
| | - Daichi Kuramochi
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Aki Ushiki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan
| | - Katsuhiko Hirakawa
- Graduate school of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Akiyoshi Fukamizu
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki, 305-8577, Japan. .,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
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13
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Oji A, Amano T, Maeta Y, Hori N, Hatsuzawa K, Sato K, Nakanishi T. Fate of methylated/unmethylated H19 imprinting control region after paternal and maternal pronuclear injection. Exp Anim 2017; 66:367-378. [PMID: 28674270 PMCID: PMC5682349 DOI: 10.1538/expanim.17-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The paternal-allele-specific methylation of the Igf2/H19 imprinting
control region (ICR) is established during gametogenesis and maintained throughout
development. To elucidate the requirement of the germline passage in the maintenance of
the imprinting methylation, we established a system introducing a methylated or
unmethylated ICR-containing DNA fragment (ICR-F) into the paternal or maternal genome by
microinjecting into the paternal or maternal pronucleus of fertilized eggs, and traced the
methylation pattern in the ICR-F. When the ICR-F was injected in a methylated form, it was
demethylated approximately to half degree at blastocyst stage but was almost completely
remethylated at 3 weeks of age. In the case of the unmethylated form, the ICR-F remained
unmethylated at the blastocyst stage, but was almost half-methylated at 3 weeks of age.
Interestingly, the paternally injected ICR-F was highly methylated compared with
maternally injected ICR-F at 3 weeks of age, partially mimicking the endogenous
methylation pattern. Moreover, introduction of mutations in the CTCF (CCCTC binding
factor) binding sites of the ICR-F, which are known to be important for the maintenance of
hypomethylated maternal ICR, induced hypermethylation of the mutated ICR-F in both
paternal and maternal pronuclear injected 3-week-old mice. Our results suggest the
presence of a protection-against-methylation activity of the CTCF binding site in
establishing the preferential paternal methylation during post-fertilization development
and the importance of germline passage in the maintenance of the parental specific
methylation at H19 ICR.
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Affiliation(s)
- Asami Oji
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Tomojiro Amano
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Yasuaki Maeta
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Naohiro Hori
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan.,Chromosome Engineering Research Center, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Kiyotaka Hatsuzawa
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Kenzo Sato
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan.,Chromosome Engineering Research Center, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan
| | - Tomoko Nakanishi
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan.,Chromosome Engineering Research Center, Tottori University, 86 Nishicho, Yonago, Tottori 683-8503, Japan.,Present address: Laboratory of Molecular Genetics, The Institute of Medical Science, Tokyo University, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
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Taylor DH, McLean CM, Wu WL, Wang AB, Soloway PD. Imprinted DNA methylation reconstituted at a non-imprinted locus. Epigenetics Chromatin 2016; 9:41. [PMID: 27688812 PMCID: PMC5034545 DOI: 10.1186/s13072-016-0094-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 09/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In mammals, tight regulation of cytosine methylation is required for embryonic development and cellular differentiation. The trans-acting DNA methyltransferases that catalyze this modification have been identified and characterized; however, these proteins lack sequence specificity, leaving the mechanism of targeting unknown. A cis-acting regulator within the Rasgrf1 imprinting control region (ICR) is necessary for establishment and maintenance of local imprinted methylation. Here, we investigate whether 3-kb of sequence from the Rasgrf1 ICR is sufficient to direct appropriate imprinted methylation and target gene expression patterns when ectopically inserted at the Wnt1 locus. RESULTS The Rasgrf1 ICR at Wnt1 lacked somatic methylation when maternally transmitted and was fully methylated upon paternal transmission, consistent with its behavior at the Rasgrf1 locus. It was unmethylated in the female germline and was enriched for methylation in the male germline, though not to the levels seen at the endogenous Rasgrf1 allele. Wnt1 expression was not imprinted by the ectopic ICR, likely due to additional sequences being required for this function. CONCLUSIONS We have identified sequences that are sufficient for partial establishment and full maintenance of the imprinted DNA methylation patterns. Because full somatic methylation can occur without full gametic methylation, we infer that somatic methylation of the Rasgrf1 ICR is not simply a consequence of maintained gametic methylation.
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Affiliation(s)
- David H Taylor
- Field of Genetics, Genomics, and Development, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA
| | - Chelsea M McLean
- Field of Genetics, Genomics, and Development, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA ; Department of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan, Amsterdam, The Netherlands
| | - Warren L Wu
- Division of Nutritional Sciences, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA
| | - Alex B Wang
- Field of Biochemistry, Molecular and Cell Biology, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA
| | - Paul D Soloway
- Field of Genetics, Genomics, and Development, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA ; Division of Nutritional Sciences, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA ; Field of Biochemistry, Molecular and Cell Biology, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY USA
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15
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Gebert C, Rong Q, Jeong S, Iben J, Pfeifer K. H19ICR mediated transcriptional silencing does not require target promoter methylation. Biochem Biophys Res Commun 2016; 476:121-6. [PMID: 27178213 DOI: 10.1016/j.bbrc.2016.05.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
Transcription of the reciprocally imprinted genes Insulin-like growth factor 2 (Igf2) and H19 is orchestrated by the 2.4-kb H19 Imprinting Control Region (H19ICR) located upstream of H19. Three known functions are associated with the H19ICR: (1) it is a germline differentially methylated region, (2) it is a transcriptional insulator, and (3) it is a transcriptional silencer. The molecular mechanisms of the DMR and insulator functions have been well characterized but the basis for the ICR's silencer function is less well understood. In order to study the role the H19ICR intrinsically plays in gene silencing, we transferred the 2.4-kb H19ICR to a heterologous non-imprinted location on chromosome 5, upstream of the alpha fetoprotein (Afp) promoter. Independent of its orientation, the 2.4-kb H19ICR silences transcription from the paternal Afp promoter. Thus silencing is a function intrinsic to this DNA element. Further, ICR mediated silencing is a developmental process that, unexpectedly, does not occur through DNA methylation at the target promoter.
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Affiliation(s)
- Claudia Gebert
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qi Rong
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sangkyun Jeong
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - James Iben
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Karl Pfeifer
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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16
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Li C, Lei B, Huang S, Zheng M, Liu Z, Li Z, Deng Y. H19 derived microRNA-675 regulates cell proliferation and migration through CDK6 in glioma. Am J Transl Res 2015; 7:1747-1764. [PMID: 26692922 PMCID: PMC4656755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 09/24/2015] [Indexed: 06/05/2023]
Abstract
The long non-coding RNA (LncRNA) H19 is one of the most highly abundant and conserved transcripts involved in the mammalian development and tumorigenesis. H19 is expressed in both embryonic cells and tumor cells, but its physical and pathological functions still need to be further studied. Our results showed that microRNA-675, a microRNA in the first exon of H19, expressed in glioma. Over-expression of microRNA-675 in a range of glioma cell lines resulted in their immoderate proliferation and migration. In addition, H19 derived microRNA-675 was down-regulated in the glioma, and CDK6, a pivotal regulator in cell cycle, was a target of microRNA-675. The survival of glioma patients with low CDK6 expression significantly increased as compared to patients with high CDK6 expression. Moreover, the CDK6 expression was inversely correlated with microRNA-675 expression in the glioma. Our results suggest that H19 derived microRNA-675 may regulate giloma cell proliferation and migration through CDK6, and predict a poor prognosis of glioma patients.
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Affiliation(s)
- Chao Li
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Bingxi Lei
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Shuaibin Huang
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Meiguang Zheng
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Zhenghao Liu
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Zhongjun Li
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
| | - Yuefei Deng
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen UniversityGuangzhou 510120, China
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17
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Matsuzaki H, Okamura E, Takahashi T, Ushiki A, Nakamura T, Nakano T, Hata K, Fukamizu A, Tanimoto K. De novo DNA methylation through the 5'-segment of the H19 ICR maintains its imprint during early embryogenesis. Development 2015; 142:3833-44. [PMID: 26417043 DOI: 10.1242/dev.126003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 09/15/2015] [Indexed: 12/30/2022]
Abstract
Genomic imprinting is a major monoallelic gene expression regulatory mechanism in mammals, and depends on gamete-specific DNA methylation of specialized cis-regulatory elements called imprinting control regions (ICRs). Allele-specific DNA methylation of the ICRs is faithfully maintained at the imprinted loci throughout development, even in early embryos where genomes undergo extensive epigenetic reprogramming, including DNA demethylation, to acquire totipotency. We previously found that an ectopically introduced H19 ICR fragment in transgenic mice acquired paternal allele-specific methylation in the somatic cells of offspring, whereas it was not methylated in sperm, suggesting that its gametic and postfertilization modifications were separable events. We hypothesized that this latter activity might contribute to maintenance of the methylation imprint in early embryos. Here, we demonstrate that methylation of the paternally inherited transgenic H19 ICR commences soon after fertilization in a maternal DNMT3A- and DNMT3L-dependent manner. When its germline methylation was partially obstructed by insertion of insulator sequences, the endogenous paternal H19 ICR also exhibited postfertilization methylation. Finally, we refined the responsible sequences for this activity in transgenic mice and found that deletion of the 5' segment of the endogenous paternal H19 ICR decreased its methylation after fertilization and attenuated Igf2 gene expression. These results demonstrate that this segment of the H19 ICR is essential for its de novo postfertilization DNA methylation, and that this activity contributes to the maintenance of imprinted methylation at the endogenous H19 ICR during early embryogenesis.
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Affiliation(s)
- Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Eiichi Okamura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Takuya Takahashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Aki Ushiki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Toshinobu Nakamura
- Department of Animal Bio-Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Toru Nakano
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kenichiro Hata
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Akiyoshi Fukamizu
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
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Insertion of an imprinted insulator into the IgH locus reveals developmentally regulated, transcription-dependent control of V(D)J recombination. Mol Cell Biol 2014; 35:529-43. [PMID: 25403489 DOI: 10.1128/mcb.00235-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The assembly of antigen receptor loci requires a developmentally regulated and lineage-specific recombination between variable (V), diversity (D), and joining (J) segments through V(D)J recombination. The process is regulated by accessibility control elements, including promoters, insulators, and enhancers. The IgH locus undergoes two recombination steps, D-J(H) and then V(H)-DJ(H), but it is unclear how the availability of the DJ(H) substrate could influence the subsequent V(H)-DJ(H) recombination step. The Eμ enhancer plays a critical role in V(D)J recombination and controls a set of sense and antisense transcripts. We epigenetically perturbed the early events at the IgH locus by inserting the imprinting control region (ICR) of the Igf2/H19 locus or a transcriptional insulator devoid of the imprinting function upstream of the Eμ enhancer. The insertions recapitulated the main epigenetic features of their endogenous counterparts, including differential DNA methylation and binding of CTCF/cohesins. Whereas the D-J(H) recombination step was unaffected, both the insulator insertions led to a severe impairment of V(H)-DJ(H) recombination. Strikingly, the inhibition of V(H)-DJ(H) recombination correlated consistently with a strong reduction of DJ(H) transcription and incomplete demethylation. Thus, developmentally regulated transcription following D-J(H) recombination emerges as an important mechanism through which the Eμ enhancer controls V(H)-DJ(H) recombination.
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19
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The chicken HS4 insulator element does not protect the H19 ICR from differential DNA methylation in yeast artificial chromosome transgenic mouse. PLoS One 2013; 8:e73925. [PMID: 24023912 PMCID: PMC3762768 DOI: 10.1371/journal.pone.0073925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 07/25/2013] [Indexed: 12/15/2022] Open
Abstract
Mono-allelic expression at the mouse IGF2/H19 locus is controlled by differential allelic DNA methylation of the imprinting control region (ICR). Because a randomly integrated H19 ICR fragment, when incorporated into the genome of transgenic mice (TgM), was allele-specifically methylated in somatic, but not in germ cells, it was suggested that allele-discriminating epigenetic signature, set within or somewhere outside of the Tg H19 ICR fragment in germ cells, was later translated into a differential DNA methylation pattern. To test if the chicken β-globin HS4 (cHS4) chromatin insulator might interfere with methylation imprinting establishment at the H19 ICR, we inserted the H19 ICR fragment, flanked by a set of floxed cHS4 core sequences, into a human β-globin locus YAC and generated TgM (insulated ICR' TgM). As controls, the cHS4 sequences were removed from one side (5'HS4-deleted ICR') or both sides (pseudo-WT ICR') of the insulated ICR' by in vivo cre-loxP recombination. The data show that while maternally inherited transgenic H19 ICR was not methylated in insulated ICR' TgM, it was significantly methylated upon paternal transmission, though the level was lower than in the pseudo-WT ICR' control. Because this reduced level of methylation was also observed in the 5'HS4-deleted ICR' TgM, we speculate that the phenotype is due to VEZF1-dependent demethylation activity, rather than the insulator function, borne in cHS4. Collectively, although we cannot rule out the possibility that cHS4 is incapable of blocking an allele-discriminating signal from outside of the transgene, the epigenetic signature appears to be marked intrinsically within the H19 ICR.
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20
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Kelsey G, Feil R. New insights into establishment and maintenance of DNA methylation imprints in mammals. Philos Trans R Soc Lond B Biol Sci 2013; 368:20110336. [PMID: 23166397 DOI: 10.1098/rstb.2011.0336] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fundamental to genomic imprinting in mammals is the acquisition of epigenetic marks that differ in male and female gametes at 'imprinting control regions' (ICRs). These marks mediate the allelic expression of imprinted genes in the offspring. Much has been learnt about the nature of imprint marks, the times during gametogenesis at which they are laid down and some of the factors responsible especially for DNA methylation. Recent work has revealed that transcription and histone modifications are critically involved in DNA methylation acquisition, and these findings allow us to propose rational models for methylation establishment. A completely novel perspective on gametic DNA methylation has emerged from epigenomic profiling. Far more differentially methylated loci have been identified in gametes than known imprinted genes, which leads us to revise the notion that methylation of ICRs is a specifically targeted process. Instead, it seems to obey default processes in germ cells, giving rise to distinct patterns of DNA methylation in sperm and oocytes. This new insight, together with the identification of proteins that preserve DNA methylation after fertilization, emphasizes the key role played by mechanisms that selectively retain differential methylation at imprinted loci during early development. Addressing these mechanisms will be essential to understanding the specificity and evolution of genomic imprinting.
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Affiliation(s)
- Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge, UK.
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21
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Okamura E, Matsuzaki H, Sakaguchi R, Takahashi T, Fukamizu A, Tanimoto K. The H19 imprinting control region mediates preimplantation imprinted methylation of nearby sequences in yeast artificial chromosome transgenic mice. Mol Cell Biol 2013; 33:858-71. [PMID: 23230275 PMCID: PMC3571351 DOI: 10.1128/mcb.01003-12] [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] [Received: 07/26/2012] [Accepted: 12/06/2012] [Indexed: 12/30/2022] Open
Abstract
In the mouse Igf2/H19 imprinted locus, differential methylation of the imprinting control region (H19 ICR) is established during spermatogenesis and is maintained in offspring throughout development. Previously, however, we observed that the paternal H19 ICR, when analyzed in yeast artificial chromosome transgenic mice (YAC-TgM), was preferentially methylated only after fertilization. To identify the DNA sequences that confer methylation imprinting, we divided the H19 ICR into two fragments (1.7 and 1.2 kb), ligated them to both ends of a λ DNA fragment into which CTCF binding sites had been inserted, and analyzed this in YAC-TgM. The maternally inherited λ sequence, normally methylated after implantation in the absence of H19 ICR sequences, became hypomethylated, demonstrating protective activity against methylation within the ICR. Meanwhile, the paternally inherited λ sequence was hypermethylated before implantation only when a 1.7-kb fragment was ligated. Consistently, when two subfragments of the H19 ICR were individually investigated for their activities in YAC-TgM, only the 1.7-kb fragment was capable of introducing paternal allele-specific DNA methylation. These results show that postfertilization methylation imprinting is conferred by a paternal allele-specific methylation activity present in a 1.7-kb DNA fragment of the H19 ICR, while maternal allele-specific activities protect the allele from de novo DNA methylation.
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Affiliation(s)
- Eiichi Okamura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Ryuuta Sakaguchi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takuya Takahashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Akiyoshi Fukamizu
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
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22
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Eun B, Sampley ML, Good AL, Gebert CM, Pfeifer K. Promoter cross-talk via a shared enhancer explains paternally biased expression of Nctc1 at the Igf2/H19/Nctc1 imprinted locus. Nucleic Acids Res 2012; 41:817-26. [PMID: 23221643 PMCID: PMC3553941 DOI: 10.1093/nar/gks1182] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Developmentally regulated transcription often depends on physical interactions between distal enhancers and their cognate promoters. Recent genomic analyses suggest that promoter–promoter interactions might play a similarly critical role in organizing the genome and establishing cell-type-specific gene expression. The Igf2/H19 locus has been a valuable model for clarifying the role of long-range interactions between cis-regulatory elements. Imprinted expression of the linked, reciprocally imprinted genes is explained by parent-of-origin-specific chromosomal loop structures between the paternal Igf2 or maternal H19 promoters and their shared tissue-specific enhancer elements. Here, we further analyze these loop structures for their composition and their impact on expression of the linked long non-coding RNA, Nctc1. We show that Nctc1 is co-regulated with Igf2 and H19 and physically interacts with the shared muscle enhancer. In fact, all three co-regulated genes have the potential to interact not only with the shared enhancer but also with each other via their enhancer interactions. Furthermore, developmental and genetic analyses indicate functional significance for these promoter–promoter interactions. Altogether, we present a novel mechanism to explain developmental specific imprinting of Nctc1 and provide new information about enhancer mechanisms and about the role of chromatin domains in establishing gene expression patterns.
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Affiliation(s)
- Bokkee Eun
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 9000 Rockville Pike, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Takahashi T, Matsuzaki H, Tomizawa SI, Okamura E, Ichiyanagi T, Fukamizu A, Sasaki H, Tanimoto K. Sequences in the H19 ICR that are transcribed as small RNA in oocytes are dispensable for methylation imprinting in YAC transgenic mice. Gene 2012; 508:26-34. [PMID: 22890135 DOI: 10.1016/j.gene.2012.07.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022]
Abstract
Allele-specific methylation of the endogenous H19 imprinting control region (ICR) is established in sperm. We previously showed that the paternal H19 ICR in yeast artificial chromosome (YAC) transgenic mice (TgM) was preferentially methylated in somatic cells, but not in germ cells, suggesting that differential methylation could be established after fertilization. In this report, we discovered small RNA molecules in growing oocytes, the nucleotide sequences of which mapped to the H19 ICR. To test if these small RNA sequences play a role in the establishment of differential methylation, we deleted the sequences from the H19 ICR DNA and generated YAC TgM. In somatic cells of these mice, methylation imprinting of the transgene was normally established. In addition, the mutant fragment was not methylated in sperm and eggs. These data demonstrate that sequences in the H19 ICR that correspond to the small RNA sequences are dispensable for methylation imprinting in YAC TgM.
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MESH Headings
- Animals
- Blotting, Southern
- Cells, Cultured
- Chromosomes, Artificial, Yeast
- DNA Methylation
- Female
- Fertilization/genetics
- Genomic Imprinting
- Locus Control Region/genetics
- Male
- Mice
- Mice, Transgenic
- Oocytes/metabolism
- RNA, Long Noncoding
- RNA, Small Untranslated/genetics
- RNA, Small Untranslated/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- Testis/metabolism
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Affiliation(s)
- Takuya Takahashi
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
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24
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Singh P, Lee DH, Szabó PE. More than insulator: multiple roles of CTCF at the H19-Igf2 imprinted domain. Front Genet 2012; 3:214. [PMID: 23087708 PMCID: PMC3471092 DOI: 10.3389/fgene.2012.00214] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/27/2012] [Indexed: 12/28/2022] Open
Abstract
CTCF (CCCTC-binding factor)-mediated insulation at the H19-Insulin-like growth factor 2 (Igf2) imprinted domain is a classic example for imprinted gene regulation. DNA methylation difference in the imprinting control region (ICR) is inherited from the gametes and subsequently determines parental allele-specific enhancer blocking and imprinted expression in the soma. Recent genetic studies showed that proper monoallelic enhancer blocking at the H19-Igf2 ICR is critical for development. Strict biallelic insulation at this locus causes perinatal lethality, whereas leaky biallelic insulation results in smaller size but no lethality. Apart from enhancer blocking, CTCF is also the master organizer of chromatin composition in the maternal allele along this imprinted domain, affecting not only histone tail covalent modifications but also those in the histone core. Additionally, CTCF binding in the soma protects the maternal allele from de novo DNA methylation. CTCF binding is not involved in the establishment of the gametic marks at the ICR, but it slightly delays de novo methylation in the maternally inherited ICR allele in prospermatogonia. This review focuses on the developmental and epigenetic consequences of CTCF binding at the H19-Igf2 ICR.
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Affiliation(s)
- Purnima Singh
- Department of Molecular and Cellular Biology, Beckman Research Institute Duarte, CA, USA
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25
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Henckel A, Chebli K, Kota SK, Arnaud P, Feil R. Transcription and histone methylation changes correlate with imprint acquisition in male germ cells. EMBO J 2011; 31:606-15. [PMID: 22117218 DOI: 10.1038/emboj.2011.425] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 10/24/2011] [Indexed: 11/10/2022] Open
Abstract
Genomic imprinting in mammals is controlled by DNA methylation imprints that are acquired in the gametes, at essential sequence elements called 'imprinting control regions' (ICRs). What signals paternal imprint acquisition in male germ cells remains unknown. To address this question, we explored histone methylation at ICRs in mouse primordial germ cells (PGCs). By 13.5 days post coitum (d.p.c.), H3 lysine-9 and H4 lysine-20 trimethylation are depleted from ICRs in male (and female) PGCs, indicating that these modifications do not signal subsequent imprint acquisition, which initiates at ∼15.5 d.p.c. Furthermore, during male PGC development, H3 lysine-4 trimethylation becomes biallelically enriched at 'maternal' ICRs, which are protected against DNA methylation, and whose promoters are active in the male germ cells. Remarkably, high transcriptional read-through is detected at the paternal ICRs H19-DMR and Ig-DMR at the time of imprint establishment, from one of the strands predominantly. Combined, our data evoke a model in which differential histone modification states linked to transcriptional events may signal the specificity of imprint acquisition during spermatogenesis.
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Affiliation(s)
- Amandine Henckel
- Institute of Molecular Genetics (IGMM), CNRS, Universities of Montpellier I and II, Montpellier, France
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26
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Abstract
Germ cell development is controlled by unique gene expression programs and involves epigenetic reprogramming of histone modifications and DNA methylation. The central event is meiosis, during which homologous chromosomes pair and recombine, processes that involve histone alterations. At unpaired regions, chromatin is repressed by meiotic silencing. After meiosis, male germ cells undergo chromatin remodeling, including histone-to-protamine replacement. Male and female germ cells are also differentially marked by parental imprints, which contribute to sex determination in insects and mediate genomic imprinting in mammals. Here, we review epigenetic transitions during gametogenesis and discuss novel insights from animal and human studies.
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Affiliation(s)
- Satya K Kota
- Institute of Molecular Genetics, CNRS UMR5535 and University of Montpellier I & II, 1919 route de Mende, 34293 Montpellier, France
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27
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MacDonald WA, Menon D, Bartlett NJ, Sperry GE, Rasheva V, Meller V, Lloyd VK. The Drosophila homolog of the mammalian imprint regulator, CTCF, maintains the maternal genomic imprint in Drosophila melanogaster. BMC Biol 2010; 8:105. [PMID: 20673338 PMCID: PMC2922095 DOI: 10.1186/1741-7007-8-105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 07/30/2010] [Indexed: 11/28/2022] Open
Abstract
Background CTCF is a versatile zinc finger DNA-binding protein that functions as a highly conserved epigenetic transcriptional regulator. CTCF is known to act as a chromosomal insulator, bind promoter regions, and facilitate long-range chromatin interactions. In mammals, CTCF is active in the regulatory regions of some genes that exhibit genomic imprinting, acting as insulator on only one parental allele to facilitate parent-specific expression. In Drosophila, CTCF acts as a chromatin insulator and is thought to be actively involved in the global organization of the genome. Results To determine whether CTCF regulates imprinting in Drosophila, we generated CTCF mutant alleles and assayed gene expression from the imprinted Dp(1;f)LJ9 mini-X chromosome in the presence of reduced CTCF expression. We observed disruption of the maternal imprint when CTCF levels were reduced, but no effect was observed on the paternal imprint. The effect was restricted to maintenance of the imprint and was specific for the Dp(1;f)LJ9 mini-X chromosome. Conclusions CTCF in Drosophila functions in maintaining parent-specific expression from an imprinted domain as it does in mammals. We propose that Drosophila CTCF maintains an insulator boundary on the maternal X chromosome, shielding genes from the imprint-induced silencing that occurs on the paternally inherited X chromosome. See commentary: http://www.biomedcentral.com/1741-7007/8/104
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28
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Matsuzaki H, Okamura E, Fukamizu A, Tanimoto K. CTCF binding is not the epigenetic mark that establishes post-fertilization methylation imprinting in the transgenic H19 ICR. Hum Mol Genet 2010; 19:1190-8. [PMID: 20047949 DOI: 10.1093/hmg/ddp589] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Hitomi Matsuzaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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29
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H19 imprinting control region methylation requires an imprinted environment only in the male germ line. Mol Cell Biol 2009; 30:1108-15. [PMID: 20038532 DOI: 10.1128/mcb.00575-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 2.4-kb H19 imprinting control region (H19ICR) is required to establish parent-of-origin-specific epigenetic marks and expression patterns at the Igf2/H19 locus. H19ICR activity is regulated by DNA methylation. The ICR is methylated in sperm but not in oocytes, and this paternal chromosome-specific methylation is maintained throughout development. We recently showed that the H19ICR can work as an ICR even when inserted into the normally nonimprinted alpha fetoprotein locus. Paternal but not maternal copies of the ICR become methylated in somatic tissue. However, the ectopic ICR remains unmethylated in sperm. To extend these findings and investigate the mechanisms that lead to methylation of the H19ICR in the male germ line, we characterized novel mouse knock-in lines. Our data confirm that the 2.4-kb element is an autonomously acting ICR whose function is not dependent on germ line methylation. Ectopic ICRs become methylated in the male germ line, but the timing of methylation is influenced by the insertion site and by additional genetic information. Our results support the idea that DNA methylation is not the primary genomic imprint and that the H19ICR insertion is sufficient to transmit parent-of-origin-dependent DNA methylation patterns independent of its methylation status in sperm.
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