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Milton AM, Marín-Gual L, Lister NC, McIntyre KL, Grady PGS, Laird MK, Bond DM, Hore TA, O'Neill RJ, Pask AJ, Renfree MB, Ruiz-Herrera A, Waters PD. Imprinted X chromosome inactivation in marsupials: The paternal X arrives at the egg with a silent DNA methylation profile. Proc Natl Acad Sci U S A 2024; 121:e2412185121. [PMID: 39190362 DOI: 10.1073/pnas.2412185121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Accepted: 07/22/2024] [Indexed: 08/28/2024] Open
Abstract
X chromosome inactivation (XCI) is an epigenetic process that results in the transcriptional silencing of one X chromosome in the somatic cells of females. This phenomenon is common to both eutherian and marsupial mammals, but there are fundamental differences. In eutherians, the X chosen for silencing is random. DNA methylation on the eutherian inactive X is high at transcription start sites (TSSs) and their flanking regions, resulting in universally high DNA methylation. This contrasts XCI in marsupials where the paternally derived X is always silenced, and in which DNA methylation is low at TSSs and flanking regions. Here, we examined the DNA methylation status of the tammar wallaby X chromosome during spermatogenesis to determine the DNA methylation profile of the paternal X prior to and at fertilization. Whole genome enzymatic methylation sequencing was carried out on enriched flow-sorted populations of premeiotic, meiotic, and postmeiotic cells. We observed that the X displayed a pattern of DNA methylation from spermatogonia to mature sperm that reflected the inactive X in female somatic tissue. Therefore, the paternal X chromosome arrives at the egg with a DNA methylation profile that reflects the transcriptionally silent X in adult female somatic tissue. We present this epigenetic signature as a candidate for the long sought-after imprint for paternal XCI in marsupials.
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Affiliation(s)
- Ashley M Milton
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Laia Marín-Gual
- Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Nicholas C Lister
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Kim L McIntyre
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Patrick G S Grady
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Melanie K Laird
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Donna M Bond
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Timothy A Hore
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Rachel J O'Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Andrew J Pask
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Aurora Ruiz-Herrera
- Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Paul D Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
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Bond DM, Ortega-Recalde O, Laird MK, Hayakawa T, Richardson KS, Reese FCB, Kyle B, McIsaac-Williams BE, Robertson BC, van Heezik Y, Adams AL, Chang WS, Haase B, Mountcastle J, Driller M, Collins J, Howe K, Go Y, Thibaud-Nissen F, Lister NC, Waters PD, Fedrigo O, Jarvis ED, Gemmell NJ, Alexander A, Hore TA. The admixed brushtail possum genome reveals invasion history in New Zealand and novel imprinted genes. Nat Commun 2023; 14:6364. [PMID: 37848431 PMCID: PMC10582058 DOI: 10.1038/s41467-023-41784-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 09/13/2023] [Indexed: 10/19/2023] Open
Abstract
Combining genome assembly with population and functional genomics can provide valuable insights to development and evolution, as well as tools for species management. Here, we present a chromosome-level genome assembly of the common brushtail possum (Trichosurus vulpecula), a model marsupial threatened in parts of their native range in Australia, but also a major introduced pest in New Zealand. Functional genomics reveals post-natal activation of chemosensory and metabolic genes, reflecting unique adaptations to altricial birth and delayed weaning, a hallmark of marsupial development. Nuclear and mitochondrial analyses trace New Zealand possums to distinct Australian subspecies, which have subsequently hybridised. This admixture allowed phasing of parental alleles genome-wide, ultimately revealing at least four genes with imprinted, parent-specific expression not yet detected in other species (MLH1, EPM2AIP1, UBP1 and GPX7). We find that reprogramming of possum germline imprints, and the wider epigenome, is similar to eutherian mammals except onset occurs after birth. Together, this work is useful for genetic-based control and conservation of possums, and contributes to understanding of the evolution of novel mammalian epigenetic traits.
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Affiliation(s)
- Donna M Bond
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | | | - Melanie K Laird
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Takashi Hayakawa
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan
| | - Kyle S Richardson
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Biology Department, University of Montana Western, Dillon, MT, 59725, USA
| | - Finlay C B Reese
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Bruce Kyle
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | | | | | | | - Amy L Adams
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Wei-Shan Chang
- School of Life and Environmental Science, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
- Health and Biosecurity, CSIRO, Canberra, ACT, Australia
| | - Bettina Haase
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | | | | | - Joanna Collins
- Tree of Life, Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Kerstin Howe
- Tree of Life, Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Yasuhiro Go
- Graduate School of Information Science, Hyogo University, Hyogo, Japan
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan
- Department of System Neuroscience, National Institute for Physiological Sciences, Aichi, Japan
| | - Francoise Thibaud-Nissen
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas C Lister
- School of Biotechnology and Biomolecular Science, Faculty of Science, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Paul D Waters
- School of Biotechnology and Biomolecular Science, Faculty of Science, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Olivier Fedrigo
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Erich D Jarvis
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY, 10065, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA
| | - Neil J Gemmell
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Alana Alexander
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Timothy A Hore
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
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Ishihara T, Hickford D, Fenelon JC, Griffith OW, Suzuki S, Renfree MB. Evolution of the short form of DNMT3A, DNMT3A2, occurred in the common ancestor of mammals. Genome Biol Evol 2022; 14:6615359. [PMID: 35749276 PMCID: PMC9254654 DOI: 10.1093/gbe/evac094] [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] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Genomic imprinting is found in marsupial and eutherian mammals, but not in monotremes. While the primary regulator of genomic imprinting in eutherians is differential DNA methylation between parental alleles, conserved imprinted genes in marsupials tend to lack DNA methylation at their promoters. DNA methylation at eutherian imprinted genes is mainly catalysed by a DNA methyltransferase (DNMT) enzyme, DNMT3A. There are two isoforms of eutherian DNMT3A: DNMT3A and DNMT3A2. DNMT3A2 is the primary isoform for establishing DNA methylation at eutherian imprinted genes and is essential for eutherian genomic imprinting. In this study, we investigated whether DNMT3A2 is also present in the two other mammalian lineages, marsupials and monotremes. We identified DNMT3A2 in both marsupials and monotremes, although imprinting has not been identified in monotremes. By analysing genomic sequences and transcriptome data across vertebrates, we concluded that the evolution of DNMT3A2 occurred in the common ancestor of mammals. In addition, DNMT3A/3A2 gene and protein expression during gametogenesis showed distinct sexual dimorphisms in a marsupial, the tammar wallaby, and this pattern coincided with the sex-specific DNA methylation reprogramming in this species as it does in mice. Our results show that DNMT3A2 is present in all mammalian groups and suggests that the basic DNMT3A/3A2-based DNA methylation mechanism is conserved at least in therian mammals.
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Affiliation(s)
- Teruhito Ishihara
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Danielle Hickford
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jane C Fenelon
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Oliver W Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Shunsuke Suzuki
- Department of Agricultural and Life Sciences, Shinshu University, Nagano, Japan
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Peng S, Gao Y, Shi S, Zhao D, Cao H, Fu T, Cai X, Xiao J. LncRNA-AK137033 inhibits the osteogenic potential of adipose-derived stem cells in diabetic osteoporosis by regulating Wnt signaling pathway via DNA methylation. Cell Prolif 2022; 55:e13174. [PMID: 34953002 PMCID: PMC8780896 DOI: 10.1111/cpr.13174] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES Bone tissue engineering based on adipose-derived stem cells (ASCs) is expected to become a new treatment for diabetic osteoporosis (DOP) patients with bone defects. However, compared with control ASCs (CON-ASCs), osteogenic potential of DOP-ASCs is decreased, which increased the difficulty of bone reconstruction in DOP patients. Moreover, the cause of the poor osteogenesis of ASCs in a hyperglycemic microenvironment has not been elucidated. Therefore, this study explored the molecular mechanism of the decline in the osteogenic potential of DOP-ASCs from the perspective of epigenetics to provide a possible therapeutic target for bone repair in DOP patients with bone defects. MATERIALS AND METHODS An animal model of DOP was established in mice. CON-ASCs and DOP-ASCs were isolated from CON and DOP mice, respectively. AK137033 small interfering RNA (SiRNA) and an AK137033 overexpression plasmid were used to regulate the expression of AK137033 in CON-ASCs and DOP-ASCs in vitro. Lentiviruses that carried shRNA-AK137033 or AK137033 cDNA were used to knockdown or overexpress AK137033, respectively, in CON-ASCs and DOP-ASCs in vivo. Hematoxylin and eosin (H&E), Masson's, alizarin red, and alkaline phosphatase (ALP) staining, micro-computed tomography (Micro-CT), flow cytometry, qPCR, western blotting, immunofluorescence, and bisulfite-specific PCR (BSP) were used to analyze the functional changes of ASCs. RESULTS The DOP mouse model was established successfully. Compared with CON-ASCs, AK137033 expression, the DNA methylation level of the sFrp2 promoter region, Wnt signaling pathway markers, and the osteogenic differentiation potential were decreased in DOP-ASCs. In vitro experiments showed that AK137033 silencing inhibited the Wnt signaling pathway and osteogenic ability of CON-ASCs by reducing the DNA methylation level in the sFrp2 promoter region. Additionally, overexpression of AK137033 in DOP-ASCs rescued these changes caused by DOP. Moreover, the same results were obtained in vivo. CONCLUSIONS LncRNA-AK137033 inhibits the osteogenic potential of DOP-ASCs by regulating the Wnt signaling pathway via modulating the DNA methylation level in the sFrp2 promoter region. This study provides an important reference to find new targets for the treatment of bone defects in DOP patients.
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Affiliation(s)
- Shuanglin Peng
- Department of Oral ImplantologyThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- State Key Laboratory of Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengduChina
- National Key Clinical SpecialtyThe Affiliated Hospital of Southwest Medical UniversityLuzhouChina
| | - Yujin Gao
- Department of Oral ImplantologyThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- Orofacial Reconstruction and Regeneration LaboratoryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- Department of Oral and Maxillofacial SurgeryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
| | - Sirong Shi
- State Key Laboratory of Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengduChina
| | - Dan Zhao
- State Key Laboratory of Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengduChina
| | - Huayue Cao
- Department of Oral ImplantologyThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- National Key Clinical SpecialtyThe Affiliated Hospital of Southwest Medical UniversityLuzhouChina
- Department of Oral and Maxillofacial SurgeryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
| | - Ting Fu
- Department of Oral ImplantologyThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- National Key Clinical SpecialtyThe Affiliated Hospital of Southwest Medical UniversityLuzhouChina
- Department of Oral and Maxillofacial SurgeryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
| | - Xiaoxiao Cai
- State Key Laboratory of Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengduChina
| | - Jingang Xiao
- Department of Oral ImplantologyThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- National Key Clinical SpecialtyThe Affiliated Hospital of Southwest Medical UniversityLuzhouChina
- Orofacial Reconstruction and Regeneration LaboratoryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
- Department of Oral and Maxillofacial SurgeryThe Affiliated Stomatology Hospital of Southwest Medical UniversityLuzhouChina
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5
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Cook LE, Newton AH, Hipsley CA, Pask AJ. Postnatal development in a marsupial model, the fat-tailed dunnart (Sminthopsis crassicaudata; Dasyuromorphia: Dasyuridae). Commun Biol 2021; 4:1028. [PMID: 34475507 PMCID: PMC8413461 DOI: 10.1038/s42003-021-02506-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Marsupials exhibit unique biological features that provide fascinating insights into many aspects of mammalian development. These include their distinctive mode of reproduction, altricial stage at birth, and the associated heterochrony that is required for their crawl to the pouch and teat attachment. Marsupials are also an invaluable resource for mammalian comparative biology, forming a distinct lineage from the extant placental and egg-laying monotreme mammals. Despite their unique biology, marsupial resources are lagging behind those available for placentals. The fat-tailed dunnart (Sminthopsis crassicaudata) is a laboratory based marsupial model, with simple and robust husbandry requirements and a short reproductive cycle making it amenable to experimental manipulations. Here we present a detailed staging series for the fat-tailed dunnart, focusing on their accelerated development of the forelimbs and jaws. This study provides the first skeletal developmental series on S. crassicaudata and provides a fundamental resource for future studies exploring mammalian diversification, development and evolution.
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Affiliation(s)
- Laura E Cook
- School of Biosciences, University of Melbourne, Parkville, VIC, Australia
| | - Axel H Newton
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, Australia
| | - Christy A Hipsley
- School of Biosciences, University of Melbourne, Parkville, VIC, Australia
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Department of Sciences, Museums Victoria, Carlton, VIC, Australia
| | - Andrew J Pask
- School of Biosciences, University of Melbourne, Parkville, VIC, Australia.
- Department of Sciences, Museums Victoria, Carlton, VIC, Australia.
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6
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Greenberg MVC. Get Out and Stay Out: New Insights Into DNA Methylation Reprogramming in Mammals. Front Cell Dev Biol 2021; 8:629068. [PMID: 33490089 PMCID: PMC7817772 DOI: 10.3389/fcell.2020.629068] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
Vertebrate genomes are marked by notably high levels of 5-cytosine DNA methylation (5meC). The clearest function of DNA methylation among members of the subphylum is repression of potentially deleterious transposable elements (TEs). However, enrichment in the bodies of protein coding genes and pericentromeric heterochromatin indicate an important role for 5meC in those genomic compartments as well. Moreover, DNA methylation plays an important role in silencing of germline-specific genes. Impaired function of major components of DNA methylation machinery results in lethality in fish, amphibians and mammals. Despite such apparent importance, mammals exhibit a dramatic loss and regain of DNA methylation in early embryogenesis prior to implantation, and then again in the cells specified for the germline. In this minireview we will highlight recent studies that shine light on two major aspects of embryonic DNA methylation reprogramming: (1) The mechanism of DNA methylation loss after fertilization and (2) the protection of discrete loci from ectopic DNA methylation deposition during reestablishment. Finally, we will conclude with some extrapolations for the evolutionary underpinnings of such extraordinary events that seemingly put the genome under unnecessary risk during a particularly vulnerable window of development.
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Affiliation(s)
- Maxim V C Greenberg
- Centre National de la Recherche Scientifique, Institut Jacques Monod, Université de Paris, Paris, France
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7
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Zhu L, Yuan C, Wang M, Liu Y, Wang Z, Seif MM. Bisphenol A-associated alterations in DNA and histone methylation affects semen quality in rare minnow Gobiocypris rarus. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 226:105580. [PMID: 32712368 DOI: 10.1016/j.aquatox.2020.105580] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 07/04/2020] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
Bisphenol A (BPA), a well-known estrogenic endocrine disruptor, is ubiquitously present in the environment, possessing the potential to interfere with the reproductive endocrine system in male mammals. However, there are limited studies on the reproductive toxicity in male aquatic animals associated with epigenetic modifications. In order to evaluate the potential effects of BPA on reproduction and better understand the underlying mechanism, adult male rare minnow (Gobiocypris rarus) were exposed to 15 μg L-1 BPA over a period of 63 d. Results showed that BPA induced congestion of blood vessels and infiltration of inflammatory cells after 21 d exposure, and decreased sperm fertilization after 63 d exposure. The genome DNA methylation levels were significantly increased throughout the treatment, and a strong positive stain were found in the spermatocyte, spermatid and sperm. The H3K4me3 level in all types of germ cell were increased by 21 d exposure while decreased following 63 d exposure. The positive stain of H3K9me3 was decreased in sperms while increased in spermatids by 21 d exposure. In addition, the H3K9me3 level was significantly increased after 63 d exposure, and a strong positive stain were found in spermatocytes, spermatids, and sperms. Our result also revealed that the transcripts of DNA methyltransferase genes (dnmt1 and dnmt3-8) and histone methyltransferase genes (mll2-5, setdb1-2 and ezh2) were also markedly changed under BPA exposure for 21-63 d. These findings indicated that BPA had toxicity in male reproductive, and DNA/histone methylation might play a vital role in the regulation of BPA-triggered the decreased of sperm quality.
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Affiliation(s)
- Long Zhu
- College of Animal Science and Technology, Northwest A&F University, Yang Ling, Shaanxi, 712100, China
| | - Cong Yuan
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Mingrong Wang
- College of Animal Science and Technology, Northwest A&F University, Yang Ling, Shaanxi, 712100, China
| | - Yan Liu
- Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Zaizhao Wang
- College of Animal Science and Technology, Northwest A&F University, Yang Ling, Shaanxi, 712100, China.
| | - Mohamed M Seif
- College of Animal Science and Technology, Northwest A&F University, Yang Ling, Shaanxi, 712100, China; Toxicology and Food Contaminants Department, National Research Centre, Cairo 11435, Egypt
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8
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DNA methylation in the vertebrate germline: balancing memory and erasure. Essays Biochem 2020; 63:649-661. [PMID: 31755927 DOI: 10.1042/ebc20190038] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Cytosine methylation is a DNA modification that is critical for vertebrate development and provides a plastic yet stable information module in addition to the DNA code. DNA methylation memory establishment, maintenance and erasure is carefully balanced by molecular machinery highly conserved among vertebrates. In mammals, extensive erasure of epigenetic marks, including 5-methylcytosine (5mC), is a hallmark of early embryo and germline development. Conversely, global cytosine methylation patterns are preserved in at least some non-mammalian vertebrates over comparable developmental windows. The evolutionary mechanisms which drove this divergence are unknown, nevertheless a direct consequence of retaining epigenetic memory in the form of 5mC is the enhanced potential for transgenerational epigenetic inheritance (TEI). Given that DNA methylation dynamics remains underexplored in most vertebrate lineages, the extent of information transferred to offspring by epigenetic modification might be underestimated.
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Ortega-Recalde O, Day RC, Gemmell NJ, Hore TA. Zebrafish preserve global germline DNA methylation while sex-linked rDNA is amplified and demethylated during feminisation. Nat Commun 2019; 10:3053. [PMID: 31311924 PMCID: PMC6635516 DOI: 10.1038/s41467-019-10894-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/31/2019] [Indexed: 12/24/2022] Open
Abstract
The germline is the only cellular lineage capable of transferring genetic information from one generation to the next. Intergenerational transmission of epigenetic memory through the germline, in the form of DNA methylation, has been proposed; however, in mammals this is largely prevented by extensive epigenetic erasure during germline definition. Here we report that, unlike mammals, the continuously-defined ‘preformed’ germline of zebrafish does not undergo genome-wide erasure of DNA methylation during development. Our analysis also uncovers oocyte-specific germline amplification and demethylation of an 11.5-kb repeat region encoding 45S ribosomal RNA (fem-rDNA). The peak of fem-rDNA amplification coincides with the initial expansion of stage IB oocytes, the poly-nucleolar cell type responsible for zebrafish feminisation. Given that fem-rDNA overlaps with the only zebrafish locus identified thus far as sex-linked, we hypothesise fem-rDNA expansion could be intrinsic to sex determination in this species. Germline cells transfer genetic information to offspring, and in zebrafish, drive sex determination. Here the authors report that, unlike mammals, the germline of zebrafish does not undergo genome-wide DNA methylation erasure, while amplifying and demethylating sex-linked rDNA during feminisation.
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Affiliation(s)
| | - Robert C Day
- Department of Biochemistry, University of Otago, Dunedin, 9016, New Zealand
| | - Neil J Gemmell
- Department of Anatomy, University of Otago, Dunedin, 9016, New Zealand
| | - Timothy A Hore
- Department of Anatomy, University of Otago, Dunedin, 9016, New Zealand.
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