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Cecalev D, Viçoso B, Galupa R. Compensation of gene dosage on the mammalian X. Development 2024; 151:dev202891. [PMID: 39140247 DOI: 10.1242/dev.202891] [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] [Indexed: 08/15/2024]
Abstract
Changes in gene dosage can have tremendous evolutionary potential (e.g. whole-genome duplications), but without compensatory mechanisms, they can also lead to gene dysregulation and pathologies. Sex chromosomes are a paradigmatic example of naturally occurring gene dosage differences and their compensation. In species with chromosome-based sex determination, individuals within the same population necessarily show 'natural' differences in gene dosage for the sex chromosomes. In this Review, we focus on the mammalian X chromosome and discuss recent new insights into the dosage-compensation mechanisms that evolved along with the emergence of sex chromosomes, namely X-inactivation and X-upregulation. We also discuss the evolution of the genetic loci and molecular players involved, as well as the regulatory diversity and potentially different requirements for dosage compensation across mammalian species.
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Affiliation(s)
- Daniela Cecalev
- Molecular, Cellular and Developmental Biology (MCD) Unit, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Beatriz Viçoso
- Institute of Science and Technology Austria (ISTA), Am Campus 1, Klosterneuburg 3400, Austria
| | - Rafael Galupa
- Molecular, Cellular and Developmental Biology (MCD) Unit, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062, Toulouse, France
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2
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de Castro RCF, Buranello TW, Recchia K, de Souza AF, Pieri NCG, Bressan FF. Emerging Contributions of Pluripotent Stem Cells to Reproductive Technologies in Veterinary Medicine. J Dev Biol 2024; 12:14. [PMID: 38804434 PMCID: PMC11130827 DOI: 10.3390/jdb12020014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 04/10/2024] [Accepted: 04/22/2024] [Indexed: 05/29/2024] Open
Abstract
The generation of mature gametes and competent embryos in vitro from pluripotent stem cells has been successfully achieved in a few species, mainly in mice, with recent advances in humans and scarce preliminary reports in other domestic species. These biotechnologies are very attractive as they facilitate the understanding of developmental mechanisms and stages that are generally inaccessible during early embryogenesis, thus enabling advanced reproductive technologies and contributing to the generation of animals of high genetic merit in a short period. Studies on the production of in vitro embryos in pigs and cattle are currently used as study models for humans since they present more similar characteristics when compared to rodents in both the initial embryo development and adult life. This review discusses the most relevant biotechnologies used in veterinary medicine, focusing on the generation of germ-cell-like cells in vitro through the acquisition of totipotent status and the production of embryos in vitro from pluripotent stem cells, thus highlighting the main uses of pluripotent stem cells in livestock species and reproductive medicine.
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Affiliation(s)
- Raiane Cristina Fratini de Castro
- Department of Surgery, Faculty of Veterinary Medicine and Animal Sciences, University of Sao Paulo, São Paulo 01001-010, SP, Brazil; (R.C.F.d.C.); (T.W.B.); (K.R.)
| | - Tiago William Buranello
- Department of Surgery, Faculty of Veterinary Medicine and Animal Sciences, University of Sao Paulo, São Paulo 01001-010, SP, Brazil; (R.C.F.d.C.); (T.W.B.); (K.R.)
| | - Kaiana Recchia
- Department of Surgery, Faculty of Veterinary Medicine and Animal Sciences, University of Sao Paulo, São Paulo 01001-010, SP, Brazil; (R.C.F.d.C.); (T.W.B.); (K.R.)
| | - Aline Fernanda de Souza
- Department of Veterinary Medicine, School of Animal Sciences and Food Engineering, University of Sao Paulo, Pirassununga 13635-900, SP, Brazil;
| | - Naira Caroline Godoy Pieri
- Department of Veterinary Medicine, School of Animal Sciences and Food Engineering, University of Sao Paulo, Pirassununga 13635-900, SP, Brazil;
| | - Fabiana Fernandes Bressan
- Department of Surgery, Faculty of Veterinary Medicine and Animal Sciences, University of Sao Paulo, São Paulo 01001-010, SP, Brazil; (R.C.F.d.C.); (T.W.B.); (K.R.)
- Department of Veterinary Medicine, School of Animal Sciences and Food Engineering, University of Sao Paulo, Pirassununga 13635-900, SP, Brazil;
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3
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Pallier PN, Ferrara M, Romagnolo F, Ferretti MT, Soreq H, Cerase A. Chromosomal and environmental contributions to sex differences in the vulnerability to neurological and neuropsychiatric disorders: Implications for therapeutic interventions. Prog Neurobiol 2022; 219:102353. [PMID: 36100191 DOI: 10.1016/j.pneurobio.2022.102353] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/22/2022] [Accepted: 09/06/2022] [Indexed: 10/14/2022]
Abstract
Neurological and neuropsychiatric disorders affect men and women differently. Multiple sclerosis, Alzheimer's disease, anxiety disorders, depression, meningiomas and late-onset schizophrenia affect women more frequently than men. By contrast, Parkinson's disease, autism spectrum condition, attention-deficit hyperactivity disorder, Tourette's syndrome, amyotrophic lateral sclerosis and early-onset schizophrenia are more prevalent in men. Women have been historically under-recruited or excluded from clinical trials, and most basic research uses male rodent cells or animals as disease models, rarely studying both sexes and factoring sex as a potential source of variation, resulting in a poor understanding of the underlying biological reasons for sex and gender differences in the development of such diseases. Putative pathophysiological contributors include hormones and epigenetics regulators but additional biological and non-biological influences may be at play. We review here the evidence for the underpinning role of the sex chromosome complement, X chromosome inactivation, and environmental and epigenetic regulators in sex differences in the vulnerability to brain disease. We conclude that there is a pressing need for a better understanding of the genetic, epigenetic and environmental mechanisms sustaining sex differences in such diseases, which is critical for developing a precision medicine approach based on sex-tailored prevention and treatment.
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Affiliation(s)
- Patrick N Pallier
- Blizard Institute, Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK.
| | - Maria Ferrara
- Institute of Psychiatry, Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy; Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States; Women's Brain Project (WBP), Switzerland
| | - Francesca Romagnolo
- Institute of Psychiatry, Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy
| | | | - Hermona Soreq
- The Edmond and Lily Safra Center of Brain Science, The Hebrew University of Jerusalem, 9190401, Israel
| | - Andrea Cerase
- EMBL-Rome, Via Ramarini 32, 00015 Monterotondo, RM, Italy; Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK; Department of Biology, University of Pisa, SS12 Abetone e Brennero 4, 56127 Pisa, Italy.
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4
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Lentini A, Cheng H, Noble JC, Papanicolaou N, Coucoravas C, Andrews N, Deng Q, Enge M, Reinius B. Elastic dosage compensation by X-chromosome upregulation. Nat Commun 2022; 13:1854. [PMID: 35388014 PMCID: PMC8987076 DOI: 10.1038/s41467-022-29414-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 03/14/2022] [Indexed: 12/24/2022] Open
Abstract
X-chromosome inactivation and X-upregulation are the fundamental modes of chromosome-wide gene regulation that collectively achieve dosage compensation in mammals, but the regulatory link between the two remains elusive and the X-upregulation dynamics are unknown. Here, we use allele-resolved single-cell RNA-seq combined with chromatin accessibility profiling and finely dissect their separate effects on RNA levels during mouse development. Surprisingly, we uncover that X-upregulation elastically tunes expression dosage in a sex- and lineage-specific manner, and moreover along varying degrees of X-inactivation progression. Male blastomeres achieve X-upregulation upon zygotic genome activation while females experience two distinct waves of upregulation, upon imprinted and random X-inactivation; and ablation of Xist impedes female X-upregulation. Female cells carrying two active X chromosomes lack upregulation, yet their collective RNA output exceeds that of a single hyperactive allele. Importantly, this conflicts the conventional dosage compensation model in which naïve female cells are initially subject to biallelic X-upregulation followed by X-inactivation of one allele to correct the X dosage. Together, our study provides key insights to the chain of events of dosage compensation, explaining how transcript copy numbers can remain remarkably stable across developmental windows wherein severe dose imbalance would otherwise be experienced by the cell.
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Affiliation(s)
- Antonio Lentini
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Huaitao Cheng
- Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
| | - J C Noble
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Natali Papanicolaou
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Christos Coucoravas
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nathanael Andrews
- Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Qiaolin Deng
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Martin Enge
- Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Björn Reinius
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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5
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Boltsis I, Grosveld F, Giraud G, Kolovos P. Chromatin Conformation in Development and Disease. Front Cell Dev Biol 2021; 9:723859. [PMID: 34422840 PMCID: PMC8371409 DOI: 10.3389/fcell.2021.723859] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/16/2021] [Indexed: 01/23/2023] Open
Abstract
Chromatin domains and loops are important elements of chromatin structure and dynamics, but much remains to be learned about their exact biological role and nature. Topological associated domains and functional loops are key to gene expression and hold the answer to many questions regarding developmental decisions and diseases. Here, we discuss new findings, which have linked chromatin conformation with development, differentiation and diseases and hypothesized on various models while integrating all recent findings on how chromatin architecture affects gene expression during development, evolution and disease.
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Affiliation(s)
- Ilias Boltsis
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, Netherlands
| | - Frank Grosveld
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, Netherlands
| | - Guillaume Giraud
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, Netherlands
- Cancer Research Center of Lyon – INSERM U1052, Lyon, France
| | - Petros Kolovos
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
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6
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Cerase A, Young AN, Ruiz NB, Buness A, Sant GM, Arnold M, Di Giacomo M, Ascolani M, Kumar M, Hierholzer A, Trigiante G, Marzi SJ, Avner P. Chd8 regulates X chromosome inactivation in mouse through fine-tuning control of Xist expression. Commun Biol 2021; 4:485. [PMID: 33859315 PMCID: PMC8050208 DOI: 10.1038/s42003-021-01945-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 02/25/2021] [Indexed: 01/22/2023] Open
Abstract
Female mammals achieve dosage compensation by inactivating one of their two X chromosomes during development, a process entirely dependent on Xist, an X-linked long non-coding RNA (lncRNA). At the onset of X chromosome inactivation (XCI), Xist is up-regulated and spreads along the future inactive X chromosome. Contextually, it recruits repressive histone and DNA modifiers that transcriptionally silence the X chromosome. Xist regulation is tightly coupled to differentiation and its expression is under the control of both pluripotency and epigenetic factors. Recent evidence has suggested that chromatin remodelers accumulate at the X Inactivation Center (XIC) and here we demonstrate a new role for Chd8 in Xist regulation in differentiating ES cells, linked to its control and prevention of spurious transcription factor interactions occurring within Xist regulatory regions. Our findings have a broader relevance, in the context of complex, developmentally-regulated gene expression.
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Affiliation(s)
- Andrea Cerase
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy.
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Alexander N Young
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Nerea Blanes Ruiz
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Andreas Buness
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Core Unit for Bioinformatics Data Analysis Universitätsklinikum Bonn, Bonn, Germany
| | - Gabrielle M Sant
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Institute of Molecular Biology gGmbH (IMB), Mainz, Germany
| | - Mirjam Arnold
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Max Planck Institute for Molecular Genetics, Otto Warburg Laboratory, Berlin, Germany
| | | | - Michela Ascolani
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
| | - Manish Kumar
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Department of Allied Health Science, Shri B. M. Patil Medical College, Hospital and Research Centre, BLDE, Vijaypura, Karnataka, India
| | - Andreas Hierholzer
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Giuseppe Trigiante
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Sarah J Marzi
- UK Dementia Research Institute, Imperial College London, London, UK
| | - Philip Avner
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo, Italy.
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7
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Young AN, Perlas E, Ruiz-Blanes N, Hierholzer A, Pomella N, Martin-Martin B, Liverziani A, Jachowicz JW, Giannakouros T, Cerase A. Deletion of LBR N-terminal domains recapitulates Pelger-Huet anomaly phenotypes in mouse without disrupting X chromosome inactivation. Commun Biol 2021; 4:478. [PMID: 33846535 PMCID: PMC8041748 DOI: 10.1038/s42003-021-01944-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 02/24/2021] [Indexed: 11/08/2022] Open
Abstract
Mutations in the gene encoding Lamin B receptor (LBR), a nuclear-membrane protein with sterol reductase activity, have been linked to rare human disorders. Phenotypes range from a benign blood disorder, such as Pelger-Huet anomaly (PHA), affecting the morphology and chromatin organization of white blood cells, to embryonic lethality as for Greenberg dysplasia (GRBGD). Existing PHA mouse models do not fully recapitulate the human phenotypes, hindering efforts to understand the molecular etiology of this disorder. Here we show, using CRISPR/Cas-9 gene editing technology, that a 236bp N-terminal deletion in the mouse Lbr gene, generating a protein missing the N-terminal domains of LBR, presents a superior model of human PHA. Further, we address recent reports of a link between Lbr and defects in X chromosome inactivation (XCI) and show that our mouse mutant displays minor X chromosome inactivation defects that do not lead to any overt phenotypes in vivo. We suggest that our N-terminal deletion model provides a valuable pre-clinical tool to the research community and will aid in further understanding the etiology of PHA and the diverse functions of LBR.
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Affiliation(s)
- Alexander Neil Young
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Emerald Perlas
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
| | - Nerea Ruiz-Blanes
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Andreas Hierholzer
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Nicola Pomella
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Belen Martin-Martin
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - Joanna W Jachowicz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Thomas Giannakouros
- Laboratory of Biochemistry, Department of Chemistry, Aristotelian University, Thessaloniki, Greece
| | - Andrea Cerase
- EMBL-Rome, Epigenetics and Neurobiology Unit, Monterotondo (RM), Italy.
- Blizard Institute, Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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8
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Mendonça ADS, Silveira MM, Rios ÁFL, Mangiavacchi PM, Caetano AR, Dode MAN, Franco MM. DNA methylation and functional characterization of the XIST gene during in vitro early embryo development in cattle. Epigenetics 2019; 14:568-588. [PMID: 30925851 DOI: 10.1080/15592294.2019.1600828] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
XIST, in association with the shorter ncRNA RepA, are essential for the initiation of X chromosome inactivation (XCI) in mice. The molecular mechanisms controlling XIST and RepA expression are well characterized in that specie. However, little is known in livestock. We aimed to characterize the DNA methylation status along the 5' portion of XIST and to characterize its transcriptional profile during early development in cattle. Three genomic regions of XIST named here as promoter, RepA and DMR1 had their DNA methylation status characterized in gametes and embryos. Expression profile of XIST was evaluated, including sense and antisense transcription. Oocytes showed higher levels of methylation than spermatozoa that was demethylated. DMR1 was hypermethylated throughout oogenesis. At the 8-16-cell embryo stage DMR1 was completed demethylated. Interestingly, RepA gain methylation during oocyte maturation and was demethylated at the blastocyst stage, later than DMR1. These results suggest that DMR1 and RepA are transient differentially methylated regions in cattle. XIST RNA was detected in matured oocytes and in single cells from the 2-cell to the morula stage, confirming the presence of maternal and embryonic transcripts. Sense and antisense transcripts were detected along the XIST in blastocyst. In silico analysis identified 63 novel transcript candidates at bovine XIST locus from both the plus and minus strands. Taking together these results improve our understanding of the molecular mechanisms involved in XCI initiation in cattle. This information may be useful for the improvement of assisted reproductive technologies in livestock considering that in vitro conditions may impair epigenetic reprogramming.
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Affiliation(s)
- Anelise Dos Santos Mendonça
- a Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology , Parque Estação Biológica , Brasília , Brazil.,b Institute of Genetics and Biochemistry , Federal University of Uberlândia , Umuarama , Brazil.,c Federal Institute of Education, Science and Technology of Piauí , Uruçuí Campus , Portal dos Cerrados , Brazil
| | - Márcia Marques Silveira
- a Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology , Parque Estação Biológica , Brasília , Brazil.,b Institute of Genetics and Biochemistry , Federal University of Uberlândia , Umuarama , Brazil
| | - Álvaro Fabrício Lopes Rios
- d Biotechnology Laboratory, Center of Biosciences and Biotechnology , North Fluminense State University , Campos dos Goytacazes , Brazil
| | - Paula Magnelli Mangiavacchi
- e Laboratory of Reproduction and Animal Genetic Improvement, Center for Agricultural Sciences and Technologies , North Fluminense State University , Campos dos Goytacazes , Brazil
| | - Alexandre Rodrigues Caetano
- f Embrapa Genetic Resources and Biotechnology , Parque Estação Biológica , Brasília , Brazil.,g School of Agriculture and Veterinary Medicine , University of Brasília, Darcy Ribeiro Campus , Brasília , Brazil
| | - Margot Alves Nunes Dode
- a Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology , Parque Estação Biológica , Brasília , Brazil.,g School of Agriculture and Veterinary Medicine , University of Brasília, Darcy Ribeiro Campus , Brasília , Brazil
| | - Maurício Machaim Franco
- a Laboratory of Animal Reproduction, Embrapa Genetic Resources and Biotechnology , Parque Estação Biológica , Brasília , Brazil.,b Institute of Genetics and Biochemistry , Federal University of Uberlândia , Umuarama , Brazil.,h Faculty of Veterinary Medicine , Federal University of Uberlândia , Umuarama , Brazil
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9
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Tikhodeyev ON. The mechanisms of epigenetic inheritance: how diverse are they? Biol Rev Camb Philos Soc 2018; 93:1987-2005. [PMID: 29790249 DOI: 10.1111/brv.12429] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/22/2018] [Accepted: 04/27/2018] [Indexed: 12/18/2022]
Abstract
Although epigenetic inheritance (EI) is a rapidly growing field of modern biology, it still has no clear place in fundamental genetic concepts which are traditionally based on the hereditary role of DNA. Moreover, not all mechanisms of EI attract the same attention, with most studies focused on DNA methylation, histone modification, RNA interference and amyloid prionization, but relatively few considering other mechanisms such as stable inhibition of plastid translation. Herein, we discuss all known and some hypothetical mechanisms that can underlie the stable inheritance of phenotypically distinct hereditary factors that lack differences in DNA sequence. These mechanisms include (i) regulation of transcription by DNA methylation, histone modifications, and transcription factors, (ii) RNA splicing, (iii) RNA-mediated post-transcriptional silencing, (iv) organellar translation, (v) protein processing by truncation, (vi) post-translational chemical modifications, (vii) protein folding, and (viii) homologous and non-homologous protein interactions. The breadth of this list suggests that any or almost any regulatory mechanism that participates in gene expression or gene-product functioning, under certain circumstances, may produce EI. Although the modes of EI are highly variable, in many epigenetic systems, stable allelic variants can be distinguished. Irrespective of their nature, all such alleles have an underlying similarity: each is a bimodular hereditary unit, whose features depend on (i) a certain epigenetic mark (epigenetic determinant) in the DNA sequence or its product, and (ii) the DNA sequence itself (DNA determinant; if this is absent, the epigenetic allele fails to perpetuate). Thus, stable allelic epigenetic inheritance (SAEI) does not contradict the hereditary role of DNA, but involves additional molecular mechanisms with no or almost no limitations to their variety.
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Affiliation(s)
- Oleg N Tikhodeyev
- Department of Genetics & Biotechnology, Saint-Petersburg State University, Saint-Petersburg 199034, Russia
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10
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Abstract
The advent of next-generation sequencing has demonstrated that eukaryotic genomes are extremely complex than what were previously thought. Recent studies revealed that in addition to protein-coding genes, nonprotein-coding genes have allocated a large fraction of the genome. Long noncoding RNA (lncRNA) genes are classified as nonprotein-coding genes, serving as a molecular signal, decoy, guide and scaffold. They were suggested to play important roles in chromatin states, epigenetic and posttranscriptional regulation of genes. Aberrant expression of lncRNAs and changes in their structure are associated with a wide spectrum of diseases ranging from different types of cancer and neurodegeneration to ?-thalassaemia. The purpose of this study was to summarize the current progress in understanding the genomic bases and origin of lncRNAs. Moreover, this study focusses on the diverse functions of lncRNAs in normal cells as well as various types of disease to illustrate the potential impacts of lncRNAs on diverse biological processes and their therapeutic significance.
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12
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Abstract
Differentiated sex chromosomes in mammals and other vertebrates evolved independently but in strikingly similar ways. Vertebrates with differentiated sex chromosomes share the problems of the unequal expression of the genes borne on sex chromosomes, both between the sexes and with respect to autosomes. Dosage compensation of genes on sex chromosomes is surprisingly variable - and can even be absent - in different vertebrate groups. Systems that compensate for different gene dosages include a wide range of global, regional and gene-by-gene processes that differ in their extent and their molecular mechanisms. However, many elements of these control systems are similar across distant phylogenetic divisions and show parallels to other gene silencing systems. These dosage systems cannot be identical by descent but were probably constructed from elements of ancient silencing mechanisms that are ubiquitous among vertebrates and shared throughout eukaryotes.
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13
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Abstract
X chromosome inactivation (XCI) is the dosage compensation mechanism that evolved in female mammals to correct the genetic imbalance of X-linked genes between sexes. X chromosome inactivation occurs in early development when one of the two X chromosomes of females is nearly-completely silenced. Differentiating Embryonic Stem cells (ESC) are regarded as a useful tool to study XCI, since they recapitulate many events occurring during early development. In this review we aim to summarise the advances in the field and to discuss the close connection between cell differentiation and X chromosome inactivation, with a particular focus on mouse ESCs.
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Affiliation(s)
- Greta Pintacuda
- />Department of Biochemistry, University of Oxford, Oxford, OX1 3QU UK
| | - Andrea Cerase
- />EMBL Mouse Biology Unit, Monterotondo, 00015 RM Italy
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14
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Abstract
Most animal genomes are diploid, and mammalian development depends on specific adaptations that have evolved secondary to diploidy. Genomic imprinting and dosage compensation restrict haploid development to early embryos. Recently, haploid mammalian development has been reinvestigated since the establishment of haploid embryonic stem cells (ESCs) from mouse embryos. Haploid cells possess one copy of each gene, facilitating the generation of loss-of-function mutations in a single step. Recessive mutations can then be assessed in forward genetic screens. Applications of haploid mammalian cell systems in screens have been illustrated in several recent publications. Haploid ESCs are characterized by a wide developmental potential and can contribute to chimeric embryos and mice. Different strategies for introducing genetic modifications from haploid ESCs into the mouse germline have been further developed. Haploid ESCs therefore introduce new possibilities in mammalian genetics and could offer an unprecedented tool for genome exploration in the future.
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Affiliation(s)
- Anton Wutz
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Hönggerberg, 8049 Zürich, Switzerland;
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15
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Igarashi M, Mikami H, Katsumi M, Miyado M, Izumi Y, Ogata T, Fukami M. SOX3 Overdosage Permits Normal Sex Development in Females with Random X Inactivation. Sex Dev 2015; 9:125-9. [PMID: 25791725 DOI: 10.1159/000377653] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2015] [Indexed: 11/19/2022] Open
Abstract
Submicroscopic duplications involving SOX3 and/or its flanking regions have been identified in 46,XX individuals both with and without disorders of sex development, raising the question whether SOX3 overdosage is sufficient to induce testicular development in genetically female individuals. Here, we report a mother-daughter pair with female phenotypes and random X inactivation. The individuals carry complex X chromosomal rearrangements leading to a copy number gain of genomic regions involving SOX3 and its upstream region. The amplified DNA fragments were detected at Xq27. These results provide evidence that SOX3 overdosage permits normal sex development in 46,XX individuals with random X inactivation.
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Affiliation(s)
- Maki Igarashi
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
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16
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Veitia RA, Veyrunes F, Bottani S, Birchler JA. X chromosome inactivation and active X upregulation in therian mammals: facts, questions, and hypotheses. J Mol Cell Biol 2015; 7:2-11. [PMID: 25564545 DOI: 10.1093/jmcb/mjv001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
X chromosome inactivation is a mechanism that modulates the expression of X-linked genes in eutherian females (XX). Ohno proposed that to achieve a proper balance between X-linked and autosomal genes, those on the active X should also undergo a 2-fold upregulation. Although some support for Ohno's hypothesis has been provided through the years, recent genomic studies testing this hypothesis have brought contradictory results and fueled debate. Thus far, there are as many results in favor as against Ohno's hypothesis, depending on the nature of the datasets and the various assumptions and thresholds involved in the analyses. However, they have confirmed the importance of dosage balance between X-linked and autosomal genes involved in stoichiometric relationships. These facts as well as questions and hypotheses are discussed below.
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Affiliation(s)
- Reiner A Veitia
- Institut Jacques Monod, Paris, France Université Paris Diderot, Paris, France
| | - Frédéric Veyrunes
- Institut des Sciences de l'Evolution de Montpellier, CNRS/Université Montpellier II, Montpellier, France
| | - Samuel Bottani
- Université Paris Diderot, Paris, France Matière et Systèmes Complexes, Paris, France
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
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Abstract
In many animals, males have one X and females have two X chromosomes. The difference in X chromosome dosage between the two sexes is compensated by mechanisms that regulate X chromosome transcription. Recent advances in genomic techniques have provided new insights into the molecular mechanisms of X chromosome dosage compensation. In this review, I summarize our current understanding of dosage imbalance in general, and then review the molecular mechanisms of X chromosome dosage compensation with an emphasis on the parallels and differences between the three well-studied model systems, M. musculus, D. melanogaster and C. elegans.
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Affiliation(s)
- Sevinç Ercan
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA
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18
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Kota SK, Roy Chowdhury D, Rao LK, Padmalatha V, Singh L, Bhadra U. Uncoupling of X-linked gene silencing from XIST binding by DICER1 and chromatin modulation on human inactive X chromosome. Chromosoma 2014; 124:249-62. [PMID: 25428210 DOI: 10.1007/s00412-014-0495-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 10/24/2014] [Accepted: 11/07/2014] [Indexed: 12/18/2022]
Abstract
In mammals, X-inactivation process is achieved by the cis-spreading of long noncoding Xist RNA over one of the female X chromosomes. The Xist binding accumulates histones H3 methylation and H4 hypoacetylation required for X inactivation that leads to proper dosage compensation of the X-linked genes. Co-transcription of Tsix, an antisense copy of Xist, blocks the Xist coating on the Xi. In mice ES cells, an RNase III enzyme Dicer1 disrupts Xist binding and methylated H3K27me3 accumulation on the Xi. Later, multiple reports opposed these findings raising a question regarding the possible role of Dicer1 in murine X silencing. Here, we show that reduction of DICER1 in human female cells increases XIST transcripts without compromising the binding of the XIST and histone tail modifications on the Xi. Moreover, DICER1-depleted cells show differential upregulation of many human X-linked genes by binding different amounts of acetylated histone predominantly on their active promoter sites. Therefore, X-linked gene silencing, which is thought to be coupled with the accumulation of XIST and heterochromatin markers on Xi can be disrupted in DICER1 depleted human cells. These results suggest that DICER1 has no apparent effect on the recruitment of heterochromatic markers on the Xi but is required for inactivation of differentially regulated genes for the maintenance of proper dosage compensation in differentiated cells.
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Affiliation(s)
- Satya Keerthi Kota
- Functional Genomics and Gene Silencing Group, Centre For Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
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19
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Abstract
Studies of X chromosome evolution in various organisms have indicated that sex-biased genes are nonrandomly distributed between the X and autosomes. Here, to extend these studies to nematodes, we annotated and analyzed X chromosome gene content in four Caenorhabditis species and in Pristionchus pacificus. Our gene expression analyses comparing young adult male and female mRNA-seq data indicate that, in general, nematode X chromosomes are enriched for genes with high female-biased expression and depleted of genes with high male-biased expression. Genes with low sex-biased expression do not show the same trend of X chromosome enrichment and depletion. Combined with the observation that highly sex-biased genes are primarily expressed in the gonad, differential distribution of sex-biased genes reflects differences in evolutionary pressures linked to tissue-specific regulation of X chromosome transcription. Our data also indicate that X dosage imbalance between males (XO) and females (XX) is influential in shaping both expression and gene content of the X chromosome. Predicted upregulation of the single male X to match autosomal transcription (Ohno's hypothesis) is supported by our observation that overall transcript levels from the X and autosomes are similar for highly expressed genes. However, comparison of differentially located one-to-one orthologs between C. elegans and P. pacificus indicates lower expression of X-linked orthologs, arguing against X upregulation. These contradicting observations may be reconciled if X upregulation is not a global mechanism but instead acts locally on a subset of tissues and X-linked genes that are dosage sensitive.
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Pessia E, Engelstädter J, Marais GAB. The evolution of X chromosome inactivation in mammals: the demise of Ohno's hypothesis? Cell Mol Life Sci 2014; 71:1383-94. [PMID: 24173285 PMCID: PMC11113734 DOI: 10.1007/s00018-013-1499-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 12/24/2022]
Abstract
Ohno's hypothesis states that dosage compensation in mammals evolved in two steps: a twofold hyperactivation of the X chromosome in both sexes to compensate for gene losses on the Y chromosome, and silencing of one X (X-chromosome inactivation, XCI) in females to restore optimal dosage. Recent tests of this hypothesis have returned contradictory results. In this review, we explain this ongoing controversy and argue that a novel view on dosage compensation evolution in mammals is starting to emerge. Ohno's hypothesis may be true for a few, dosage-sensitive genes only. If so few genes are compensated, then why has XCI evolved as a chromosome-wide mechanism? This and several other questions raised by the new data in mammals are discussed, and future research directions are proposed.
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Affiliation(s)
- Eugénie Pessia
- Laboratoire de Biométrie et Biologie Évolutive, Centre National de la Recherche Scientifique, Université Lyon 1, Bat. Gregor Mendel, 16 rue Raphaël Dubois, 69622, Villeurbanne Cedex, France,
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21
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Barakat TS, Loos F, van Staveren S, Myronova E, Ghazvini M, Grootegoed JA, Gribnau J. The trans-activator RNF12 and cis-acting elements effectuate X chromosome inactivation independent of X-pairing. Mol Cell 2014; 53:965-78. [PMID: 24613346 DOI: 10.1016/j.molcel.2014.02.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 12/18/2013] [Accepted: 01/24/2014] [Indexed: 11/27/2022]
Abstract
X chromosome inactivation (XCI) in female placental mammals is a vital mechanism for dosage compensation between X-linked and autosomal genes. XCI starts with activation of Xist and silencing of the negative regulator Tsix, followed by cis spreading of Xist RNA over the future inactive X chromosome (Xi). Here, we show that XCI does not require physical contact between the two X chromosomes (X-pairing) but is regulated by trans-acting diffusible factors. We found that the X-encoded trans-acting and dose-dependent XCI-activator RNF12 acts in concert with the cis-regulatory region containing Jpx, Ftx, and Xpr to activate Xist and to overcome repression by Tsix. RNF12 acts at two subsequent steps; two active copies of Rnf12 drive initiation of XCI, and one copy needs to remain active to maintain XCI toward establishment of the Xi. This two-step mechanism ensures that XCI is very robust and fine-tuned, preventing XCI of both X chromosomes.
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Affiliation(s)
- Tahsin Stefan Barakat
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Friedemann Loos
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Selma van Staveren
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Elvira Myronova
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Mehrnaz Ghazvini
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Erasmus Stem Cell Institute, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J Anton Grootegoed
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Joost Gribnau
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
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Assessment of gene expression in peripheral blood using RNAseq before and after weight restoration in anorexia nervosa. Psychiatry Res 2013; 210:287-93. [PMID: 23778302 PMCID: PMC3805820 DOI: 10.1016/j.psychres.2013.05.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 05/06/2013] [Accepted: 05/20/2013] [Indexed: 12/30/2022]
Abstract
We examined gene expression in the blood of six females with anorexia nervosa (AN) before and after weight restoration using RNAseq. AN cases (aged 19-39) completed clinical assessments and had blood drawn for RNA at hospital admission (T1,<~75% ideal body weight, IBW) and again at discharge (T2,≥ ~ 85% IBW). To examine the relationship between weight restoration and differential gene expression, normalized gene expression levels were analyzed using a paired design. We found 564 genes whose expression was nominally significantly different following weight restoration (p<0.01, 231 increased and 333 decreased). With a more stringent significance threshold (false discovery rate q<0.05), 67 genes met criteria for differential expression. Of the top 20 genes, CYP11A1, C16orf11, LINC00235, and CPA3 were down-regulated more than two-fold after weight restoration while multiple olfactory receptor genes (OR52J3, OR51L1, OR51A4, and OR51A2) were up-regulated more than two-fold after weight restoration. Pathway analysis revealed up-regulation of two broad pathways with largely overlapping genes, one related to protein secretion and signaling and the other associated with defense response to bacterial regulation. Although results are preliminary secondary to a small sample size, these data provide initial evidence of transcriptional alterations during weight restoration in AN.
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Dupont C, Gribnau J. Different flavors of X-chromosome inactivation in mammals. Curr Opin Cell Biol 2013; 25:314-21. [PMID: 23578369 DOI: 10.1016/j.ceb.2013.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/27/2013] [Accepted: 03/13/2013] [Indexed: 12/22/2022]
Abstract
Dosage compensation of X-linked gene products between the sexes in therians has culminated in the inactivation of one of the two X chromosomes in female cells. Over the years, the mouse has been the preferred animal model to study this X-chromosome inactivation (XCI) process in placental mammals (eutherians). Similar to the imprinted inactivation of the paternally inherited X chromosome (Xp) in marsupials (methatherians), the Xp is inactivated during early mouse development. In this eutherian model, cell derivatives of the primitive endoderm (PE) and trophectoderm (TE) will continue to display this imprinted form of XCI. Cells developing from the mouse epiblast will reactivate the Xp, and subsequently initiate XCI of either the Xp or the maternally inherited Xm, in a random manner. Examination of XCI in other eutherians and in metatherians, however, indicates clear differences in the form and timing of XCI. This review highlights and discusses imprinted and random XCI from such a comparative viewpoint.
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Affiliation(s)
- Cathérine Dupont
- Department of Reproduction and Development, Erasmus MC, University Medical Center, 3015GE Rotterdam, The Netherlands
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24
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Regulation of Mammalian Gene Dosage by Long Noncoding RNAs. Biomolecules 2013; 3:124-42. [PMID: 24970160 PMCID: PMC4030888 DOI: 10.3390/biom3010124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/23/2013] [Accepted: 01/25/2013] [Indexed: 12/14/2022] Open
Abstract
Recent transcriptome studies suggest that long noncoding RNAs (lncRNAs) are key components of the mammalian genome, and their study has become a new frontier in biomedical research. In fact, lncRNAs in the mammalian genome were identified and studied at particular epigenetic loci, including imprinted loci and X-chromosome inactivation center, at least two decades ago—long before development of high throughput sequencing technology. Since then, researchers have found that lncRNAs play essential roles in various biological processes, mostly during development. Since much of our understanding of lncRNAs originates from our knowledge of these well-established lncRNAs, in this review we will focus on lncRNAs from the X-chromosome inactivation center and the Dlk1-Dio3 imprinted cluster as examples of lncRNA mechanisms functioning in the epigenetic regulation of mammalian genes.
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25
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Abstract
Marsupial and eutherian mammals inactivate one X chromosome in female somatic cells in what is thought to be a means of compensating for the unbalanced X chromosome dosage between XX females and XY males. The hypothesis of X chromosome inactivation (XCI) was first published by Mary Lyon just over 50 years ago, with the discovery of XCI in marsupials occurring a decade later. However, we are still piecing together the evolutionary origins of this fascinating epigenetic mechanism. From the very first studies on marsupial X inactivation, it was apparent that, although there were some similarities between marsupial and eutherian XCI, there were also some striking differences. For instance, the paternally derived X was found to be preferentially silenced in marsupials, although the silencing was often incomplete, which was in contrast to the random and more tightly controlled inactivation of the X chromosome in eutherians. Many of these earlier studies used isozymes to study the activity of just a few genes in marsupials. The sequencing of several marsupial genomes and the advent of molecular cytogenetic techniques have facilitated more in-depth studies into marsupial X chromosome inactivation and allowed more detailed comparisons of the features of XCI to be made. Several important findings have come from such comparisons, among which is the absence of the XIST gene in marsupials, a non-coding RNA gene with a critical role in eutherian XCI, and the discovery of the marsupial RSX gene, which appears to perform a similar role to XIST. Here I review the history of marsupial XCI studies, the latest advances that have been made and the impact they have had towards unravelling the evolution of XCI in mammals.
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26
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Chan WL, Chang YS, Yang WK, Huang HD, Chang JG. Very long non-coding RNA and human disease. Biomedicine (Taipei) 2012. [DOI: 10.1016/j.biomed.2012.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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