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Schuff M, Strong AD, Welborn LK, Ziermann-Canabarro JM. Imprinting as Basis for Complex Evolutionary Novelties in Eutherians. BIOLOGY 2024; 13:682. [PMID: 39336109 PMCID: PMC11428813 DOI: 10.3390/biology13090682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2024] [Revised: 08/24/2024] [Accepted: 08/28/2024] [Indexed: 09/30/2024]
Abstract
The epigenetic phenomenon of genomic imprinting is puzzling. While epigenetic modifications in general are widely known in most species, genomic imprinting in the animal kingdom is restricted to autosomes of therian mammals, mainly eutherians, and to a lesser extent in marsupials. Imprinting causes monoallelic gene expression. It represents functional haploidy of certain alleles while bearing the evolutionary cost of diploidization, which is the need of a complex cellular architecture and the danger of producing aneuploid cells by mitotic and meiotic errors. The parent-of-origin gene expression has stressed many theories. Most prominent theories, such as the kinship (parental conflict) hypothesis for maternally versus paternally derived alleles, explain only partial aspects of imprinting. The implementation of single-cell transcriptome analyses and epigenetic research allowed detailed study of monoallelic expression in a spatial and temporal manner and demonstrated a broader but much more complex and differentiated picture of imprinting. In this review, we summarize all these aspects but argue that imprinting is a functional haploidy that not only allows a better gene dosage control of critical genes but also increased cellular diversity and plasticity. Furthermore, we propose that only the occurrence of allele-specific gene regulation mechanisms allows the appearance of evolutionary novelties such as the placenta and the evolutionary expansion of the eutherian brain.
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Affiliation(s)
- Maximillian Schuff
- Next Fertility St. Gallen, Kürsteinerstrasse 2, 9015 St. Gallen, Switzerland
| | - Amanda D Strong
- Department of Anatomy, Howard University College of Medicine, 520 W St. NW, Washington, DC 20059, USA
| | - Lyvia K Welborn
- Department of Anatomy, Howard University College of Medicine, 520 W St. NW, Washington, DC 20059, USA
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2
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Tyson HR, Harrison DJ, Higgs MJ, Isles AR, John RM. Deficiency of the paternally-expressed imprinted Peg3 gene in mice has sexually dimorphic consequences for offspring communication and social behaviour. Front Neurosci 2024; 18:1374781. [PMID: 38595977 PMCID: PMC11002209 DOI: 10.3389/fnins.2024.1374781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
Introduction Imprinted genes are expressed from one parental allele as a consequence of epigenetic processes initiated in the germline. Consequently, their ability to influence phenotype depends on their parent-of-origin. Recent research suggests that the sex of the individual expressing the imprinted gene is also important. We have previously reported that genetically wildtype (WT) dams carrying and caring for pups mutant for PEG3 exhibit anxiety-like behaviours and their mutant pups show a reduction in ultrasonic vocalisation when separated from their mothers. Sex-specificity was not examined. Methods WT female mice were mated with WT, heterozygous Peg3-/+ or homozygous Peg3-/- studs to generate all WT (control), 50:50 mixed or 100% mutant litters, respectively, followed by behavioural assessment of both dams and their pups. Results We reproduced our original finding that WT dams carrying and caring for 100% mutant litters exhibit postpartum anxiety-like symptoms and delayed pup retrieval. Additionally, these WT dams were found to allocate less time to pup-directed care behaviours relative to controls. Male Peg3-deficient pups demonstrated significantly reduced vocalisation with a more subtle communication deficit in females. Postweaning, male mutants exhibited deficits across a number of key social behaviours as did WT males sharing their environment with mutants. Only modest variations in social behaviour were detected in experimental females. Discussion We have experimentally demonstrated that Peg3 deficiency confined to the offspring causes anxiety in mouse mothers and atypical behaviour including deficits in communication in their male offspring. A male-specific reduction in expression PEG3 in the fetally-derived placenta has previously been associated with maternal depression in human pregnancy. Maternal mood disorders such as depression and anxiety are associated with delays in language development and neuroatypical behaviour more common in sons. Peg3 deficiency could drive the association of maternal and offspring behavioural disorders reported in humans.
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Affiliation(s)
- Hannah R. Tyson
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - David J. Harrison
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Mathew J. Higgs
- Behavioural Genetics Group, MRC Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Anthony R. Isles
- Behavioural Genetics Group, MRC Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Rosalind M. John
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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3
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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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4
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John RM, Higgs MJ, Isles AR. Imprinted genes and the manipulation of parenting in mammals. Nat Rev Genet 2023; 24:783-796. [PMID: 37714957 DOI: 10.1038/s41576-023-00644-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2023] [Indexed: 09/17/2023]
Abstract
Genomic imprinting refers to the parent-of-origin expression of genes, which originates from epigenetic events in the mammalian germ line. The evolution of imprinting may reflect a conflict over resource allocation early in life, with silencing of paternal genes in offspring soliciting increased maternal provision and silencing of maternal genes limiting demands on the mother. Parental caregiving has been identified as an area of potential conflict, with several imprinted genes serendipitously found to directly influence the quality of maternal care. Recent systems biology approaches, based on single-cell RNA sequencing data, support a more deliberate relationship, which is reinforced by the finding that imprinted genes expressed in the offspring influence the quality of maternal caregiving. These bidirectional, reiterative relationships between parents and their offspring are critical both for short-term survival and for lifelong wellbeing, with clear implications for human health.
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Scagliotti V, Vignola ML, Willis T, Howard M, Marinelli E, Gaston-Massuet C, Andoniadou C, Charalambous M. Imprinted Dlk1 dosage as a size determinant of the mammalian pituitary gland. eLife 2023; 12:e84092. [PMID: 37589451 PMCID: PMC10468206 DOI: 10.7554/elife.84092] [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: 10/10/2022] [Accepted: 08/16/2023] [Indexed: 08/18/2023] Open
Abstract
Co-regulated genes of the Imprinted Gene Network are involved in the control of growth and body size, and imprinted gene dysfunction underlies human paediatric disorders involving the endocrine system. Imprinted genes are highly expressed in the pituitary gland, among them, Dlk1, a paternally expressed gene whose membrane-bound and secreted protein products can regulate proliferation and differentiation of multiple stem cell populations. Dosage of circulating DLK1 has been previously implicated in the control of growth through unknown molecular mechanisms. Here we generate a series of mouse genetic models to modify levels of Dlk1 expression in the pituitary gland and demonstrate that the dosage of DLK1 modulates the process of stem cell commitment with lifelong impact on pituitary gland size. We establish that stem cells are a critical source of DLK1, where embryonic disruption alters proliferation in the anterior pituitary, leading to long-lasting consequences on growth hormone secretion later in life.
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Affiliation(s)
- Valeria Scagliotti
- Department of Medical and Molecular Genetics, Faculty of Life Sciences and Medicine, King’s College LondonLondonUnited Kingdom
| | - Maria Lillina Vignola
- Department of Medical and Molecular Genetics, Faculty of Life Sciences and Medicine, King’s College LondonLondonUnited Kingdom
| | - Thea Willis
- Department of Medical and Molecular Genetics, Faculty of Life Sciences and Medicine, King’s College LondonLondonUnited Kingdom
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College LondonLondonUnited Kingdom
| | - Mark Howard
- MRC Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College LondonLondonUnited Kingdom
| | - Eugenia Marinelli
- Department of Medical and Molecular Genetics, Faculty of Life Sciences and Medicine, King’s College LondonLondonUnited Kingdom
| | - Carles Gaston-Massuet
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of LondonLondonUnited Kingdom
| | - Cynthia Andoniadou
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College LondonLondonUnited Kingdom
| | - Marika Charalambous
- Department of Medical and Molecular Genetics, Faculty of Life Sciences and Medicine, King’s College LondonLondonUnited Kingdom
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6
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Chou MY, Cao X, Hou KC, Tsai MH, Lee CY, Kuo MF, Wu VC, Huang HY, Akbarian S, Chang SK, Hu CY, Lin SW, Huang HS. Mir125b-2 imprinted in human but not mouse brain regulates hippocampal function and circuit in mice. Commun Biol 2023; 6:267. [PMID: 36918719 PMCID: PMC10014956 DOI: 10.1038/s42003-023-04655-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 03/03/2023] [Indexed: 03/16/2023] Open
Abstract
Genomic imprinting predominantly occurs in the placenta and brain. Few imprinted microRNAs have been identified in the brain, and their functional roles in the brain are not clear. Here we show paternal, but not maternal, expression of MIR125B2 in human but not mouse brain. Moreover, Mir125b-2m-/p- mice showed impaired learning and memory, and anxiety, whose functions were hippocampus-dependent. Hippocampal granule cells from Mir125b-2m-/p- mice displayed increased neuronal excitability, increased excitatory synaptic transmission, and decreased inhibitory synaptic transmission. Glutamate ionotropic receptor NMDA type subunit 2A (Grin2a), a key regulator of synaptic plasticity, was physically bound by miR-125b-2 and upregulated in the hippocampus of Mir125b-2m-/p- mice. Taken together, our findings demonstrate MIR125B2 imprinted in human but not mouse brain, mediated learning, memory, and anxiety, regulated excitability and synaptic transmission in hippocampal granule cells, and affected hippocampal expression of Grin2a. Our work provides functional mechanisms of a species-specific imprinted microRNA in the brain.
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Affiliation(s)
- Ming-Yi Chou
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Xuhui Cao
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Kuan-Chu Hou
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Meng-Han Tsai
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Chih-Yu Lee
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Meng-Fai Kuo
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, 10051, Taiwan
| | - Vin-Cent Wu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Hsin-Yi Huang
- Department of Pathology, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Schahram Akbarian
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sheng-Kai Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Chung-Yi Hu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Shu-Wha Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan
| | - Hsien-Sung Huang
- Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan.
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7
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Weinberg-Shukron A, Ben-Yair R, Takahashi N, Dunjić M, Shtrikman A, Edwards CA, Ferguson-Smith AC, Stelzer Y. Balanced gene dosage control rather than parental origin underpins genomic imprinting. Nat Commun 2022; 13:4391. [PMID: 35906226 PMCID: PMC9338321 DOI: 10.1038/s41467-022-32144-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 07/19/2022] [Indexed: 11/25/2022] Open
Abstract
Mammalian parental imprinting represents an exquisite form of epigenetic control regulating the parent-specific monoallelic expression of genes in clusters. While imprinting perturbations are widely associated with developmental abnormalities, the intricate regional interplay between imprinted genes makes interpreting the contribution of gene dosage effects to phenotypes a challenging task. Using mouse models with distinct deletions in an intergenic region controlling imprinting across the Dlk1-Dio3 domain, we link changes in genetic and epigenetic states to allelic-expression and phenotypic outcome in vivo. This determined how hierarchical interactions between regulatory elements orchestrate robust parent-specific expression, with implications for non-imprinted gene regulation. Strikingly, flipping imprinting on the parental chromosomes by crossing genotypes of complete and partial intergenic element deletions rescues the lethality of each deletion on its own. Our work indicates that parental origin of an epigenetic state is irrelevant as long as appropriate balanced gene expression is established and maintained at imprinted loci. Here the authors investigate whether for imprinted genes the parent-of-origin of the expressed allele or rather appropriate gene dosage is more important for normal development. Using the differentially methylated region of Dlk1-Dio3 gene involved in imprinting, they show that correct parent-of-origin imprinting pattern is secondary to balanced gene dosage.
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Affiliation(s)
- Ariella Weinberg-Shukron
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel.,Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, United Kingdom
| | - Raz Ben-Yair
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Nozomi Takahashi
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, United Kingdom
| | - Marko Dunjić
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Alon Shtrikman
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Carol A Edwards
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, United Kingdom
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, United Kingdom.
| | - Yonatan Stelzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel.
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8
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Van de Pette M, Dimond A, Galvão AM, Millership SJ, To W, Prodani C, McNamara G, Bruno L, Sardini A, Webster Z, McGinty J, French PMW, Uren AG, Castillo-Fernandez J, Watkinson W, Ferguson-Smith AC, Merkenschlager M, John RM, Kelsey G, Fisher AG. Epigenetic changes induced by in utero dietary challenge result in phenotypic variability in successive generations of mice. Nat Commun 2022; 13:2464. [PMID: 35513363 PMCID: PMC9072353 DOI: 10.1038/s41467-022-30022-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/13/2022] [Indexed: 11/22/2022] Open
Abstract
Transmission of epigenetic information between generations occurs in nematodes, flies and plants, mediated by specialised small RNA pathways, modified histones and DNA methylation. Similar processes in mammals can also affect phenotype through intergenerational or trans-generational mechanisms. Here we generate a luciferase knock-in reporter mouse for the imprinted Dlk1 locus to visualise and track epigenetic fidelity across generations. Exposure to high-fat diet in pregnancy provokes sustained re-expression of the normally silent maternal Dlk1 in offspring (loss of imprinting) and increased DNA methylation at the somatic differentially methylated region (sDMR). In the next generation heterogeneous Dlk1 mis-expression is seen exclusively among animals born to F1-exposed females. Oocytes from these females show altered gene and microRNA expression without changes in DNA methylation, and correct imprinting is restored in subsequent generations. Our results illustrate how diet impacts the foetal epigenome, disturbing canonical and non-canonical imprinting mechanisms to modulate the properties of successive generations of offspring.
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Affiliation(s)
- Mathew Van de Pette
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Andrew Dimond
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - António M Galvão
- Epigenetics Programme, The Babraham Institute, Cambridge, CB22 3AT, UK
- Institute of Animal Reproduction and Food Research of PAS, Department of Reproductive Immunology and Pathology, Olsztyn, Poland
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Steven J Millership
- Department of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Wilson To
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Chiara Prodani
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Gráinne McNamara
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Ludovica Bruno
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Alessandro Sardini
- Whole Animal Physiology and Imaging, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Zoe Webster
- Transgenics and Embryonic Stem Cell Laboratory, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - James McGinty
- Photonics Group, Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Anthony G Uren
- Cancer Genomics Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | | | - William Watkinson
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Matthias Merkenschlager
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Rosalind M John
- Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge, CB22 3AT, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK
- Wellcome-MRC Institute of Metabolic Science-Metabolic Research Laboratories, Cambridge, CB2 0QQ, UK
| | - Amanda G Fisher
- Lymphocyte Development & Epigenetic Memory Groups, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.
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Gutherz OR, Deyssenroth M, Li Q, Hao K, Jacobson JL, Chen J, Jacobson SW, Carter RC. Potential roles of imprinted genes in the teratogenic effects of alcohol on the placenta, somatic growth, and the developing brain. Exp Neurol 2021; 347:113919. [PMID: 34752786 DOI: 10.1016/j.expneurol.2021.113919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 12/22/2022]
Abstract
Despite several decades of research and prevention efforts, fetal alcohol spectrum disorders (FASD) remain the most common preventable cause of neurodevelopmental disabilities worldwide. Animal and human studies have implicated fetal alcohol-induced alterations in epigenetic programming as a chief mechanism in FASD. Several studies have demonstrated fetal alcohol-related alterations in methylation and expression of imprinted genes in placental, brain, and embryonic tissue. Imprinted genes are epigenetically regulated in a parent-of-origin-specific manner, in which only the maternal or paternal allele is expressed, and the other allele is silenced. The chief functions of imprinted genes are in placental development, somatic growth, and neurobehavior-three domains characteristically affected in FASD. In this review, we summarize the growing body of literature characterizing prenatal alcohol-related alterations in imprinted gene methylation and/or expression and discuss potential mechanistic roles for these alterations in the teratogenic effects of prenatal alcohol exposure. Future research is needed to examine potential physiologic mechanisms by which alterations in imprinted genes disrupt development in FASD, which may, in turn, elucidate novel targets for intervention. Furthermore, mechanistic alterations in imprinted gene expression and/or methylation in FASD may inform screening assays that identify individuals with FASD neurobehavioral deficits who may benefit from early interventions.
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Affiliation(s)
- Olivia R Gutherz
- Institute of Human Nutrition, Columbia University Medical Center, United States of America
| | - Maya Deyssenroth
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, United States of America
| | - Qian Li
- Department of Environmental Medicine & Public Health, Icahn School of Medicine at Mount Sinai, United States of America
| | - Ke Hao
- Department of Environmental Medicine & Public Health, Icahn School of Medicine at Mount Sinai, United States of America
| | - Joseph L Jacobson
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, United States of America; Department of Human Biology, University of Cape Town Faculty of Health Sciences, South Africa
| | - Jia Chen
- Department of Environmental Medicine & Public Health, Icahn School of Medicine at Mount Sinai, United States of America
| | - Sandra W Jacobson
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, United States of America; Department of Human Biology, University of Cape Town Faculty of Health Sciences, South Africa
| | - R Colin Carter
- Institute of Human Nutrition, Columbia University Medical Center, United States of America; Departments of Emergency Medicine and Pediatrics, Columbia University Medical Center, United States of America.
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10
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Abstract
DLK1 is a maternally imprinted, paternally expressed gene coding for the transmembrane protein Delta-like homologue 1 (DLK1), a non-canonical NOTCH ligand with well-described roles during development, and tumor-supportive functions in several aggressive cancer forms. Here, we review the many functions of DLK1 as a regulator of stem cell pools and tissue differentiation in tissues such as brain, muscle, and liver. Furthermore, we review recent evidence supporting roles for DLK1 in the maintenance of aggressive stem cell characteristics of tumor cells, specifically focusing on central nervous system tumors, neuroblastoma, and hepatocellular carcinoma. We discuss NOTCH -dependent as well as NOTCH-independent functions of DLK1, and focus particularly on the complex pattern of DLK1 expression and cleavage that is finely regulated from a spatial and temporal perspective. Progress in recent years suggest differential functions of extracellular, soluble DLK1 as a paracrine stem cell niche-secreted factor, and has revealed a role for the intracellular domain of DLK1 in cell signaling and tumor stemness. A better understanding of DLK1 regulation and signaling may enable therapeutic targeting of cancer stemness by interfering with DLK1 release and/or intracellular signaling.
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Affiliation(s)
- Elisa Stellaria Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Alexander Pietras
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
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11
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Montalbán-Loro R, Lassi G, Lozano-Ureña A, Perez-Villalba A, Jiménez-Villalba E, Charalambous M, Vallortigara G, Horner AE, Saksida LM, Bussey TJ, Trejo JL, Tucci V, Ferguson-Smith AC, Ferrón SR. Dlk1 dosage regulates hippocampal neurogenesis and cognition. Proc Natl Acad Sci U S A 2021; 118:e2015505118. [PMID: 33712542 PMCID: PMC7980393 DOI: 10.1073/pnas.2015505118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Neurogenesis in the adult brain gives rise to functional neurons, which integrate into neuronal circuits and modulate neural plasticity. Sustained neurogenesis throughout life occurs in the subgranular zone (SGZ) of the dentate gyrus in the hippocampus and is hypothesized to be involved in behavioral/cognitive processes such as memory and in diseases. Genomic imprinting is of critical importance to brain development and normal behavior, and exemplifies how epigenetic states regulate genome function and gene dosage. While most genes are expressed from both alleles, imprinted genes are usually expressed from either the maternally or the paternally inherited chromosome. Here, we show that in contrast to its canonical imprinting in nonneurogenic regions, Delta-like homolog 1 (Dlk1) is expressed biallelically in the SGZ, and both parental alleles are required for stem cell behavior and normal adult neurogenesis in the hippocampus. To evaluate the effects of maternally, paternally, and biallelically inherited mutations within the Dlk1 gene in specific behavioral domains, we subjected Dlk1-mutant mice to a battery of tests that dissociate and evaluate the effects of Dlk1 dosage on spatial learning ability and on anxiety traits. Importantly, reduction in Dlk1 levels triggers specific cognitive abnormalities that affect aspects of discriminating differences in environmental stimuli, emphasizing the importance of selective absence of imprinting in this neurogenic niche.
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Affiliation(s)
- Raquel Montalbán-Loro
- ERI Biotecmed-Departamento de Biología Celular, Universidad de Valencia, 46010 Valencia,Spain
| | - Glenda Lassi
- Genetics and Epigenetics of Behaviour (GEB) Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Translational Science and Experimental Medicine Research and Early Development, Respiratory and Immunology, BioPharmaceuticals R&D, AstraZeneca, Cambridge Biomedical Campus, Cambridge CB2 0AA, United Kingdom
| | - Anna Lozano-Ureña
- ERI Biotecmed-Departamento de Biología Celular, Universidad de Valencia, 46010 Valencia,Spain
| | - Ana Perez-Villalba
- ERI Biotecmed-Departamento de Biología Celular, Universidad de Valencia, 46010 Valencia,Spain
- Faculty of Psychology, Laboratory of Animal Behavior Phenotype (LABP), Universidad Católica de Valencia, 46100 Valencia, Spain
| | | | - Marika Charalambous
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | | | - Alexa E Horner
- Synome Ltd, Babraham, Cambridge CB22 3AT, United Kingdom
| | - Lisa M Saksida
- Department of Psychology, Medical Research Council and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Molecular Medicine Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5K8, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
- The Brain and Mind Institute, Western University, London, ON N6A 5B7, Canada
| | - Timothy J Bussey
- Department of Psychology, Medical Research Council and Wellcome Trust Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge CB2 3EB, United Kingdom
- Molecular Medicine Research Laboratories, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5K8, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
- The Brain and Mind Institute, Western University, London, ON N6A 5B7, Canada
| | - José Luis Trejo
- Department of Translational Neuroscience, Cajal Institute, The Spanish National Research Council, Madrid 28002, Spain
| | - Valter Tucci
- Genetics and Epigenetics of Behaviour (GEB) Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | | | - Sacri R Ferrón
- ERI Biotecmed-Departamento de Biología Celular, Universidad de Valencia, 46010 Valencia,Spain;
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12
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Chen Y, Gao H, Liu Q, Xie W, Li B, Cheng S, Guo J, Fang Q, Zhu H, Wang Z, Wang J, Li C, Zhang Y. Functional characterization of DLK1/MEG3 locus on chromosome 14q32.2 reveals the differentiation of pituitary neuroendocrine tumors. Aging (Albany NY) 2020; 13:1422-1439. [PMID: 33472171 PMCID: PMC7835058 DOI: 10.18632/aging.202376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
Pituitary neuroendocrine tumors (PitNETs) represent the neoplastic proliferation of the anterior pituitary gland. Transcription factors play a key role in the differentiation of PitNETs. However, for a substantial proportion of PitNETs, the etiology is poorly understood. According to the transcription data of 172 patients, we found the imprinting disorders of the 14q32.2 region and DLK1/MEG3 locus associated with the differentiation of PitNETs. DLK1/MEG3 locus promoted somatotroph differentiation and inhibited tumor proliferation in PIT1(+) patients, furthermore, the level of DLK1 played a critical role in the trend of somatotroph or lactotroph differentiation. Anti-DLK1 monoclonal antibody blockade or siMEG3 both indicated that the DLK1/MEG3 significantly promoted the synthesis and secretion of GH/IGF-1 and inhibited cell proliferation. In addition, loss of DLK1 activated the mTOR signaling pathway in high DLK1-expressing and PIT1(+) GH3 cell lines, a mild effect in the low DLK1-expressing and PIT1(+) MMQ cell lines and no effect in the PIT1(-) ATT20 cell line. These findings emphasize that expression at the DLK1/MEG3 locus plays a key role in the differentiation of PitNETs, especially somatotroph adenomas, and provide potential molecular target data for patient stratification and treatment in the future.
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Affiliation(s)
- Yiyuan Chen
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Hua Gao
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Qian Liu
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Weiyan Xie
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Bin Li
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Sen Cheng
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Jing Guo
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Qiuyue Fang
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
| | - Haibo Zhu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
| | - Zhuang Wang
- Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Jichao Wang
- Department of Neurosurgery, People's Hospital of Xinjiang Uygur Autonomous Region, Xinjiang 830001, China
| | - Chuzhong Li
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing 100070, China
- Brain Tumor Center, Beijing Institute for Brain Disorders, Beijing 100070, China
| | - Yazhuo Zhang
- Department of Cell Biology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100070, China
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing 100070, China
- Brain Tumor Center, Beijing Institute for Brain Disorders, Beijing 100070, China
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13
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Finn J, Sottoriva K, Pajcini KV, Kitajewski JK, Chen C, Zhang W, Malik AB, Liu Y. Dlk1-Mediated Temporal Regulation of Notch Signaling Is Required for Differentiation of Alveolar Type II to Type I Cells during Repair. Cell Rep 2020; 26:2942-2954.e5. [PMID: 30865885 PMCID: PMC6464111 DOI: 10.1016/j.celrep.2019.02.046] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 01/15/2019] [Accepted: 02/12/2019] [Indexed: 01/26/2023] Open
Abstract
Lung alveolar type I cells (AT1) and alveolar type II cells (AT2) regulate the structural integrity and function of alveoli. AT1, covering ∼95% of the surface area, are responsible for gas exchange, whereas AT2 serve multiple functions, including alveolar repair through proliferation and differentiation into AT1. However, the signaling mechanisms for alveolar repair remain unclear. Here, we demonstrate, in Pseudomonas aeruginosa-induced acute lung injury in mice, that non-canonical Notch ligand Dlk1 (delta-like 1 homolog) is essential for AT2-to-AT1 differentiation. Notch signaling was activated in AT2 at the onset of repair but later suppressed by Dlk1. Deletion of Dlk1 in AT2 induced persistent Notch activation, resulting in stalled transition to AT1 and accumulation of an intermediate cell population that expressed low levels of both AT1 and AT2 markers. Thus, Dlk1 expression leads to precisely timed inhibition of Notch signaling and activates AT2-to-AT1 differentiation, leading to alveolar repair.
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Affiliation(s)
- Johanna Finn
- Department of Pharmacology, The University of Illinois College of Medicine, Chicago, IL 60612, USA; The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Kilian Sottoriva
- Department of Pharmacology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Kostandin V Pajcini
- Department of Pharmacology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Jan K Kitajewski
- Department of Physiology and Biophysics, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Chang Chen
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Wei Zhang
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Asrar B Malik
- Department of Pharmacology, The University of Illinois College of Medicine, Chicago, IL 60612, USA; The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Yuru Liu
- Department of Pharmacology, The University of Illinois College of Medicine, Chicago, IL 60612, USA; The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
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14
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Hanin G, Ferguson-Smith AC. The evolution of genomic imprinting: Epigenetic control of mammary gland development and postnatal resource control. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2019; 12:e1476. [PMID: 31877240 DOI: 10.1002/wsbm.1476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 12/11/2022]
Abstract
Genomic imprinting is an epigenetically regulated process leading to gene expression according to its parental origin. Imprinting is essential for prenatal growth and development, regulating nutritional resources to offspring, and contributing to a favored theory about the evolution of imprinting being due to a conflict between maternal and paternal genomes for the control of prenatal resources-the so-called kinship hypothesis. Genomic imprinting has been mainly studied during embryonic and placental development; however, maternal nutrient provisioning is not restricted to the prenatal period. In this context, the mammary gland acts at the maternal-offspring interface providing milk to the newborn. Maternal care including lactation supports the offspring, delivering nutrients and bioactive molecules protecting against infections and contributing to healthy organ development and immune maturation. The normal developmental cycle of the mammary gland-pregnancy, lactation, involution-is vital for this process, raising the question of whether genomic imprinting might also play a role in postnatal nutrient transfer by controlling mammary gland development. Characterizing the function and epigenetic regulation of imprinted genes in the mammary gland cycle may therefore provide novel insights into the evolution of imprinting since the offspring's paternal genome is absent from the mammary gland, in addition to increasing our knowledge of postnatal nutrition and its relation to life-long health. This article is categorized under: Developmental Biology > Developmental Processes in Health and Disease.
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Affiliation(s)
- Geula Hanin
- Department of Genetics, University of Cambridge, Cambridge, UK
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15
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Millership SJ, Van de Pette M, Withers DJ. Genomic imprinting and its effects on postnatal growth and adult metabolism. Cell Mol Life Sci 2019; 76:4009-4021. [PMID: 31270580 PMCID: PMC6785587 DOI: 10.1007/s00018-019-03197-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/10/2019] [Accepted: 06/17/2019] [Indexed: 12/25/2022]
Abstract
Imprinted genes display parent-of-origin-specific expression with this epigenetic system of regulation found exclusively in therian mammals. Historically, defined imprinted gene functions were almost solely focused on pregnancy and the influence on the growth parameters of the developing embryo and placenta. More recently, a number of postnatal functions have been identified which converge on resource allocation, both for animals in the nest and in adults. While many of the prenatal functions of imprinted genes that have so far been described adhere to the "parental conflict" hypothesis, no clear picture has yet emerged on the functional role of imprints on postnatal metabolism. As these roles are uncovered, interest in the potential for these genes to influence postnatal metabolism and associated adult-onset disease outcomes when dysregulated has gathered pace. Here, we review the published data on imprinted genes and their influence on postnatal metabolism, starting in the nest, and then progressing through to adulthood. When observing the functional effects of these genes on adult metabolism, we must always be careful to acknowledge the influence both of direct expression in the relevant metabolic tissue, but also indirect metabolic programming effects caused by their modulation of both in utero and postnatal growth trajectories.
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Affiliation(s)
- Steven J Millership
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
| | - Mathew Van de Pette
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Dominic J Withers
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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16
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Garcia-Gallastegi P, Ruiz-García A, Ibarretxe G, Rivero-Hinojosa S, González-Siccha AD, Laborda J, Crende O, Unda F, García-Ramírez JJ. Similarities and differences in tissue distribution of DLK1 and DLK2 during E16.5 mouse embryogenesis. Histochem Cell Biol 2019; 152:47-60. [DOI: 10.1007/s00418-019-01778-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2019] [Indexed: 10/27/2022]
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17
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Correra RM, Ollitrault D, Valente M, Mazzola A, Adalsteinsson BT, Ferguson-Smith AC, Marazzi G, Sassoon DA. The imprinted gene Pw1/Peg3 regulates skeletal muscle growth, satellite cell metabolic state, and self-renewal. Sci Rep 2018; 8:14649. [PMID: 30279563 PMCID: PMC6168517 DOI: 10.1038/s41598-018-32941-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/18/2018] [Indexed: 12/16/2022] Open
Abstract
Pw1/Peg3 is an imprinted gene expressed from the paternally inherited allele. Several imprinted genes, including Pw1/Peg3, have been shown to regulate overall body size and play a role in adult stem cells. Pw1/Peg3 is expressed in muscle stem cells (satellite cells) as well as a progenitor subset of muscle interstitial cells (PICs) in adult skeletal muscle. We therefore examined the impact of loss-of-function of Pw1/Peg3 during skeletal muscle growth and in muscle stem cell behavior. We found that constitutive loss of Pw1/Peg3 function leads to a reduced muscle mass and myofiber number. In newborn mice, the reduction in fiber number is increased in homozygous mutants as compared to the deletion of only the paternal Pw1/Peg3 allele, indicating that the maternal allele is developmentally functional. Constitutive and a satellite cell-specific deletion of Pw1/Peg3, revealed impaired muscle regeneration and a reduced capacity of satellite cells for self-renewal. RNA sequencing analyses revealed a deregulation of genes that control mitochondrial function. Consistent with these observations, Pw1/Peg3 mutant satellite cells displayed increased mitochondrial activity coupled with accelerated proliferation and differentiation. Our data show that Pw1/Peg3 regulates muscle fiber number determination during fetal development in a gene-dosage manner and regulates satellite cell metabolism in the adult.
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Affiliation(s)
- Rosa Maria Correra
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
| | - David Ollitrault
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France
| | - Mariana Valente
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France
| | - Alessia Mazzola
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France
| | - Bjorn T Adalsteinsson
- Department of Physiology Development and Neuroscience, Downing Street, University of Cambridge, Cambridge, United Kingdom
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Giovanna Marazzi
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France.
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France.
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France.
| | - David A Sassoon
- UMR S 1166 INSERM (Stem Cells and Regenerative Medicine Team), University of Pierre and Marie Curie Paris VI, Paris, 75634, France.
- Institute of Cardiometabolism and Nutrition (ICAN), Paris, 75013, France.
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 970, Paris Cardiovascular Research Center, Université René Descartes Paris, Paris, France.
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18
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Abstract
ABSTRACT
In the 1980s, mouse nuclear transplantation experiments revealed that both male and female parental genomes are required for successful development to term (McGrath and Solter, 1983; Surani and Barton, 1983). This non-equivalence of parental genomes is because imprinted genes are predominantly expressed from only one parental chromosome. Uniparental inheritance of these genomic regions causes paediatric growth disorders such as Beckwith–Wiedemann and Silver–Russell syndromes (reviewed in Peters, 2014). More than 100 imprinted genes have now been discovered and the functions of many of these genes have been assessed in murine models. The first such genes described were the fetal growth factor insulin-like growth factor 2 (Igf2) and its inhibitor Igf2 receptor (Igf2r) (DeChiara et al., 1991; Lau et al., 1994; Wang et al., 1994). Since then, it has emerged that most imprinted genes modulate fetal growth and resource acquisition in a variety of ways. First, imprinted genes are required for the development of a functional placenta, the organ that mediates the exchange of nutrients between mother and fetus. Second, these genes act in an embryo-autonomous manner to affect the growth rate and organogenesis. Finally, imprinted genes can signal the nutritional status between mother and fetus, and can modulate levels of maternal care. Importantly, many imprinted genes have been shown to affect postnatal growth and energy homeostasis. Given that abnormal birthweight correlates with adverse adult metabolic health, including obesity and cardiovascular disease, it is crucial to understand how the modulation of this dosage-sensitive, epigenetically regulated class of genes can contribute to fetal and postnatal growth, with implications for lifelong health and disease.
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Affiliation(s)
- Féaron C. Cassidy
- Queen Mary University of London, Charterhouse Square, LondonEC1M 6BQ, UK
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19
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Van de Pette M, Abbas A, Feytout A, McNamara G, Bruno L, To WK, Dimond A, Sardini A, Webster Z, McGinty J, Paul EJ, Ungless MA, French PMW, Withers DJ, Uren A, Ferguson-Smith AC, Merkenschlager M, John RM, Fisher AG. Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults. Cell Rep 2017; 18:1090-1099. [PMID: 28147266 PMCID: PMC5300902 DOI: 10.1016/j.celrep.2017.01.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/22/2016] [Accepted: 01/07/2017] [Indexed: 12/13/2022] Open
Abstract
Imprinted genes are regulated according to parental origin and can influence embryonic growth and metabolism and confer disease susceptibility. Here, we designed sensitive allele-specific reporters to non-invasively monitor imprinted Cdkn1c expression in mice and showed that expression was modulated by environmental factors encountered in utero. Acute exposure to chromatin-modifying drugs resulted in de-repression of paternally inherited (silent) Cdkn1c alleles in embryos that was temporary and resolved after birth. In contrast, deprivation of maternal dietary protein in utero provoked permanent de-repression of imprinted Cdkn1c expression that was sustained into adulthood and occurred through a folate-dependent mechanism of DNA methylation loss. Given the function of imprinted genes in regulating behavior and metabolic processes in adults, these results establish imprinting deregulation as a credible mechanism linking early-life adversity to later-life outcomes. Furthermore, Cdkn1c-luciferase mice offer non-invasive tools to identify factors that disrupt epigenetic processes and strategies to limit their long-term impact. Allele-specific expression of imprinted Cdkn1c imaged in vivo using bioluminescence Chromatin-modifying drugs applied in utero transiently de-repress Cdkn1c imprinting In utero exposure to low-protein diet permanently disrupts the Cdkn1c imprint Folate supplements during gestation protect against loss of Cdkn1c imprinting
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Affiliation(s)
- Mathew Van de Pette
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Allifia Abbas
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Amelie Feytout
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Gráinne McNamara
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Ludovica Bruno
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Wilson K To
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Andrew Dimond
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Alessandro Sardini
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Zoe Webster
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - James McGinty
- Photonics Group, Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ, UK
| | - Eleanor J Paul
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Mark A Ungless
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ, UK
| | - Dominic J Withers
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Anthony Uren
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Matthias Merkenschlager
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Rosalind M John
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Amanda G Fisher
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK.
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20
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Crespi BJ, Procyshyn TL. Williams syndrome deletions and duplications: Genetic windows to understanding anxiety, sociality, autism, and schizophrenia. Neurosci Biobehav Rev 2017; 79:14-26. [DOI: 10.1016/j.neubiorev.2017.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 04/06/2017] [Accepted: 05/06/2017] [Indexed: 12/30/2022]
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21
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Enterina JR, Enfield KSS, Anderson C, Marshall EA, Ng KW, Lam WL. DLK1-DIO3 imprinted locus deregulation in development, respiratory disease, and cancer. Expert Rev Respir Med 2017; 11:749-761. [PMID: 28715922 DOI: 10.1080/17476348.2017.1355241] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
INTRODUCTION The imprinted DLK1-DIO3 locus at 14q32.1-32.31 holds biological significance in fetal development, whereby imprinting errors are causal to developmental disorders. Emerging evidence has implicated this locus in other diseases including cancer, highlighting the biological parallels between fetal organ and tumour development. Areas covered: Controlled regulation of gene expression from the imprinted DLK1-DIO3 locus at 14q32.1-32.31 is crucial for proper fetal development. Deregulation of locus gene expression due to imprinting errors has been mechanistically linked to the developmental disorders Kagami-Ogata Syndrome and Temple Syndrome. In adult tissues, deregulation of locus genes has been associated with multiple malignancies although the causal genetic mechanisms remain largely uncharacterised. Here, we summarize the genetic mechanisms underlying the developmental disorders that arise as a result of improper locus imprinting and the resulting developmental phenotypes, emphasizing both the coding and noncoding components of the locus. We further highlight biological parallels common to both fetal development and disease, with a specific focus on lung development, respiratory disease, and lung cancer. Expert commentary: Many commonalities between respiratory and developmental defects have emerged with respect to the 14q32 locus, emphasizing the importance of studying the effects of imprinting on gene regulation patterns at this locus in both biological settings.
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Affiliation(s)
- Jhon R Enterina
- a British Columbia Cancer Research Centre , Vancouver , BC , Canada
| | | | | | - Erin A Marshall
- a British Columbia Cancer Research Centre , Vancouver , BC , Canada
| | - Kevin W Ng
- a British Columbia Cancer Research Centre , Vancouver , BC , Canada
| | - Wan L Lam
- a British Columbia Cancer Research Centre , Vancouver , BC , Canada
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22
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Mitchell M, Strick R, Strissel PL, Dittrich R, McPherson NO, Lane M, Pliushch G, Potabattula R, Haaf T, El Hajj N. Gene expression and epigenetic aberrations in F1-placentas fathered by obese males. Mol Reprod Dev 2017; 84:316-328. [PMID: 28186371 DOI: 10.1002/mrd.22784] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/06/2017] [Indexed: 12/17/2022]
Abstract
Gene expression and/or epigenetic deregulation may have consequences for sperm and blastocysts, as well as for the placenta, together potentially contributing to problems observed in offspring. We previously demonstrated specific perturbations of fertilization, blastocyst formation, implantation, as well as aberrant glucose metabolism and adiposity in offspring using a mouse model of paternal obesity. The current investigation analyzed gene expression and methylation of specific CpG residues in F1 placentas of pregnancies fathered by obese and normal-weight male mice, using real-time PCR and bisulfite pyrosequencing. Our aim was to determine if paternal obesity deregulated placental gene expression and DNA methylation when compared to normal-weight males. Gene methylation of sperm DNA was analyzed and compared to placentas to address epigenetic transmission. Of the 10 paternally expressed genes (Pegs), 11 genes important for development and transport of nutrients, and the long-terminal repeat Intracisternal A particle (IAP) elements, derived from a member of the class II endogenous retroviral gene family, we observed a significant effect of paternal diet-induced obesity on deregulated expression of Peg3, Peg9, Peg10, and the nutrient transporter gene Slc38a2, and aberrant DNA methylation of the Peg9 promoter in F1 placental tissue. Epigenetic changes in Peg9 were also found in sperm from obese fathers. We therefore propose that paternal obesity renders changes in gene expression and/or methylation throughout the placental genome, which could contribute to the reproductive problems related to fertility and to the metabolic, long-term health impact on offspring.
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Affiliation(s)
- Megan Mitchell
- Department of Obstetrics and Gynaecology, Erlangen University Hospital, Laboratory for Molecular Medicine, Universitaetsstrasse, Erlangen, Germany.,School of Paediatrics and Reproductive Health, The Robinson Institute, University of Adelaide, South Australia, Australia
| | - Reiner Strick
- Department of Obstetrics and Gynaecology, Erlangen University Hospital, Laboratory for Molecular Medicine, Universitaetsstrasse, Erlangen, Germany
| | - Pamela L Strissel
- Department of Obstetrics and Gynaecology, Erlangen University Hospital, Laboratory for Molecular Medicine, Universitaetsstrasse, Erlangen, Germany
| | - Ralf Dittrich
- Department of Obstetrics and Gynaecology, Erlangen University Hospital, Laboratory for Molecular Medicine, Universitaetsstrasse, Erlangen, Germany
| | - Nicole O McPherson
- School of Paediatrics and Reproductive Health, The Robinson Institute, University of Adelaide, South Australia, Australia
| | - Michelle Lane
- School of Paediatrics and Reproductive Health, The Robinson Institute, University of Adelaide, South Australia, Australia.,Repromed, Dulwich, Adelaide, South Australia
| | - Galyna Pliushch
- Institute of Human Genetics, Julius Maximillians University, Biozentrum, Am Hubland, Würzburg, Germany
| | - Ramya Potabattula
- Institute of Human Genetics, Julius Maximillians University, Biozentrum, Am Hubland, Würzburg, Germany
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximillians University, Biozentrum, Am Hubland, Würzburg, Germany
| | - Nady El Hajj
- Institute of Human Genetics, Julius Maximillians University, Biozentrum, Am Hubland, Würzburg, Germany
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23
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Cleaton MAM, Dent CL, Howard M, Corish JA, Gutteridge I, Sovio U, Gaccioli F, Takahashi N, Bauer SR, Charnock-Jones DS, Powell TL, Smith GCS, Ferguson-Smith AC, Charalambous M. Fetus-derived DLK1 is required for maternal metabolic adaptations to pregnancy and is associated with fetal growth restriction. Nat Genet 2016; 48:1473-1480. [PMID: 27776119 DOI: 10.1038/ng.3699] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/23/2016] [Indexed: 01/16/2023]
Abstract
Pregnancy is a state of high metabolic demand. Fasting diverts metabolism to fatty acid oxidation, and the fasted response occurs much more rapidly in pregnant women than in non-pregnant women. The product of the imprinted DLK1 gene (delta-like homolog 1) is an endocrine signaling molecule that reaches a high concentration in the maternal circulation during late pregnancy. By using mouse models with deleted Dlk1, we show that the fetus is the source of maternal circulating DLK1. In the absence of fetally derived DLK1, the maternal fasting response is impaired. Furthermore, we found that maternal circulating DLK1 levels predict embryonic mass in mice and can differentiate healthy small-for-gestational-age (SGA) infants from pathologically small infants in a human cohort. Therefore, measurement of DLK1 concentration in maternal blood may be a valuable method for diagnosing human disorders associated with impaired DLK1 expression and to predict poor intrauterine growth and complications of pregnancy.
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Affiliation(s)
- Mary A M Cleaton
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Claire L Dent
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Mark Howard
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | | | - Ulla Sovio
- Department of Obstetrics and Gynaecology, University of Cambridge and NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, UK
| | - Francesca Gaccioli
- Department of Obstetrics and Gynaecology, University of Cambridge and NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, UK
| | | | - Steven R Bauer
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, USA
| | - D Steven Charnock-Jones
- Department of Obstetrics and Gynaecology, University of Cambridge and NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, UK
| | - Theresa L Powell
- Department of Pediatrics, Section for Neonatology, University of Colorado Anschutz Medical Campus, Denver, Colorado, USA
| | - Gordon C S Smith
- Department of Obstetrics and Gynaecology, University of Cambridge and NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, UK
| | - Anne C Ferguson-Smith
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Department of Genetics, University of Cambridge, Cambridge, UK
| | - Marika Charalambous
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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24
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Lahbib-Mansais Y, Barasc H, Marti-Marimon M, Mompart F, Iannuccelli E, Robelin D, Riquet J, Yerle-Bouissou M. Expressed alleles of imprinted IGF2, DLK1 and MEG3 colocalize in 3D-preserved nuclei of porcine fetal cells. BMC Cell Biol 2016; 17:35. [PMID: 27716032 PMCID: PMC5045652 DOI: 10.1186/s12860-016-0113-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/20/2016] [Indexed: 11/23/2022] Open
Abstract
Background To explore the relationship between spatial genome organization and gene expression in the interphase nucleus, we used a genomic imprinting model, which offers parental-specific gene expression. Using 3D FISH in porcine fetal liver cells, we compared the nuclear organization of the two parental alleles (expressed or not) of insulin-like growth factor 2 (IGF2), a paternally imprinted gene located on chromosome 2. We investigated whether its nuclear positioning favors specific locus associations. We also tested whether IGF2 is implicated in long-range chromatin trans-associations as previously shown in the mouse model species for its reciprocal imprinted gene H19. Results We focused on the 3D position of IGF2 alleles, with respect to their individual chromosome 2 territories. The paternally expressed allele was tagged with nascent RNA. There were no significant differences in the position of the two alleles (p = 0.06). To determine long-range chromatin trans-interactions, we chose 12 genes, some of which are known to be imprinted in mammalian model species and belong to a network of imprinted genes (i.e. SLC38A4, DLK1, MEG3, and ZAC1). We screened them and ABCG2, OSBP2, OSBPL1, RPL32, NF1, ZAR1, SEP15, GPC3 for associations with IGF2 in liver cells. All imprinted genes tested showed an association with IGF2. The DLK1/MEG3 locus showed the highest rate of colocalization. This gene association was confirmed by 3D FISH (in 20 % of the nuclei analyzed), revealing also the close proximity of chromosomes 2 and 7 (in 60 % of nuclei). Furthermore, our observations showed that the expressed paternal IGF2 allele is involved in this association. This IGF2-(DLK1/MEG3) association also occurred in a high percentage of fetal muscle cells (36 % of nuclei). Finally, we showed that nascent IGF2, DLK1 and MEG3 RNAs can associate in pairs or in a three-way combination. Conclusion Our results show that trans-associations occur between three imprinted genes IGF2, DLK1 and MEG3 both in fetal liver and muscle cells. All three expressed alleles associated in muscle cells. Our findings suggest that the 3D nuclear organization is linked to the transcriptional state of these genes. Electronic supplementary material The online version of this article (doi:10.1186/s12860-016-0113-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Harmonie Barasc
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
| | - Maria Marti-Marimon
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
| | - Florence Mompart
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
| | - Eddie Iannuccelli
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
| | - David Robelin
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
| | - Juliette Riquet
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan, France
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25
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Hu J, Zhao W, Zhan S, Xiao P, Zhou J, Wang L, Li L, Zhang H, Niu L, Zhong T. Delta-like 1 homolog in Capra hircus: molecular characteristics, expression pattern and phylogeny. Mol Biol Rep 2016; 43:563-71. [PMID: 27108112 DOI: 10.1007/s11033-016-3989-8] [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: 12/28/2015] [Accepted: 04/19/2016] [Indexed: 01/24/2023]
Abstract
To research the molecular characteristics, expression pattern and phylogeny of the Delta-like 1 homolog gene (Dlk1) in goats. Dlk1 transcripts were identified in the Jianyang Da'er goats by reverse-transcription polymerase chain reaction (RT-PCR). Phylogenetic trees were constructed by Bayesian inference and neighbor-joining methods. Quantitative real-time PCR (qPCR), western blotting and in situ hybridization were performed to analyze the expression pattern of Dlk1. Five alternatively transcripts were identified in different tissues and designated as Dlk1-AS1, 2, 3, 4 and 5. Compared with the normal transcript Dlk1-AS1, Dlk1-AS4 and Dlk1-AS5 retained the identical open reading frame (ORF) and encoded proteins with truncated epidermal-growth-factor like repeats of 121 and 83 amino acids, respectively. Using the Bayesian inference method, the consensus phylogenetic tree indicated that caprine Dlk1 had a closer relationship with bovine Dlk1 than with Dlk1 from pigs, humans and mice. qPCR revealed high expression levels of Dlk1 in the kidney (P < 0.01). However, mRNA and protein levels presented an inconsistent correlation, possibly because of post-transcriptional regulation. RNA in situ hybridization indicated that Dlk1 mRNA was localized in the interlobular bile duct and alongside the hepatocyte nuclei, in the epithelial cells of proximal and distal convoluted tubules and in the connective region between the mesothelium and myocardium in the heart. The Dlk1 gene in goats produces alternatively spliced transcripts, with specific expression and cellular localization patterns. These findings would lay the foundation for further study.
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Affiliation(s)
- Jiangtao Hu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Wei Zhao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Siyuan Zhan
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Ping Xiao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Jingxuan Zhou
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Linjie Wang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Li Li
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Hongping Zhang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Lili Niu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Tao Zhong
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China.
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26
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García-Gallastegui P, Luzuriaga J, Aurrekoetxea M, Baladrón V, Ruiz-Hidalgo MJ, García-Ramírez JJ, Laborda J, Unda F, Ibarretxe G. Reduced salivary gland size and increased presence of epithelial progenitor cells in DLK1-deficient mice. Cell Tissue Res 2015; 364:513-525. [DOI: 10.1007/s00441-015-2344-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/10/2015] [Indexed: 01/23/2023]
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27
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Xu X, Ectors F, Davis EE, Pirottin D, Cheng H, Farnir F, Hadfield T, Cockett N, Charlier C, Georges M, Takeda H. Ectopic Expression of Retrotransposon-Derived PEG11/RTL1 Contributes to the Callipyge Muscular Hypertrophy. PLoS One 2015; 10:e0140594. [PMID: 26474044 PMCID: PMC4608697 DOI: 10.1371/journal.pone.0140594] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 09/27/2015] [Indexed: 11/18/2022] Open
Abstract
The callipyge phenotype is an ovine muscular hypertrophy characterized by polar overdominance: only heterozygous +Mat/CLPGPat animals receiving the CLPG mutation from their father express the phenotype. +Mat/CLPGPat animals are characterized by postnatal, ectopic expression of Delta-like 1 homologue (DLK1) and Paternally expressed gene 11/Retrotransposon-like 1 (PEG11/RTL1) proteins in skeletal muscle. We showed previously in transgenic mice that ectopic expression of DLK1 alone induces a muscular hypertrophy, hence demonstrating a role for DLK1 in determining the callipyge hypertrophy. We herein describe newly generated transgenic mice that ectopically express PEG11 in skeletal muscle, and show that they also exhibit a muscular hypertrophy phenotype. Our data suggest that both DLK1 and PEG11 act together in causing the muscular hypertrophy of callipyge sheep.
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Affiliation(s)
- Xuewen Xu
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Fabien Ectors
- Transgenic platform, FARAH and GIGA Research Center, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Erica E. Davis
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Dimitri Pirottin
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Huijun Cheng
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Frédéric Farnir
- Unit of Biostatistics, FARAH and Faculty of Veterinary Medicine, University of Liège, Boulevard de Colonster, Liège, Belgium
| | - Tracy Hadfield
- Department of Animal, Dairy and Veterinary sciences, Utah State University, Logan, Utah, United States of America
| | - Noelle Cockett
- Department of Animal, Dairy and Veterinary sciences, Utah State University, Logan, Utah, United States of America
| | - Carole Charlier
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Michel Georges
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
| | - Haruko Takeda
- Unit of Animal Genomics, GIGA Research Center and Faculty of Veterinary Medicine, University of Liège, 1 Avenue de l’Hôpital, Liège, Belgium
- * E-mail:
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28
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Exogenous administration of DLK1 ameliorates hepatic steatosis and regulates gluconeogenesis via activation of AMPK. Int J Obes (Lond) 2015; 40:356-65. [PMID: 26315841 DOI: 10.1038/ijo.2015.173] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/07/2015] [Accepted: 08/13/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND/OBJECTIVES Activation of Notch signaling pathologically enhances lipogenesis and gluconeogenesis in the liver causing non-alcoholic fatty liver disease (NAFLD) and diabetes. Delta-like 1 homolog (DLK1), an imprinted gene that can modulate adipogenesis and muscle development in mice, was found as an inhibitory regulator of Notch signaling. Therefore, we investigated the metabolic effect of exogenous DLK1 in vitro and in vivo. SUBJECTS/METHODS A soluble DLK1 peptide was generated with fusion between a human Fc fragment and extracellular domain of DLK1. Male db/db mice were randomly assigned to two groups: vehicle treated and DLK1-treated group (25 mg kg(-1), intraperitoneal injection, twice a week for 4 weeks). Primary mice hepatocytes and HepG2 cells were used for in vitro experiments. RESULTS After 4 weeks of DLK1 administration, hepatic triglyceride content and lipid droplets in liver tissues, as well as serum levels of liver enzymes, were markedly decreased in db/db mice. DLK1 treatment induced phosphorylation of AMPK and ACC and suppressed nuclear expression of SREBP-1c in the mouse liver or hepatocytes, indicating regulation of fatty acid oxidation and synthesis pathways. Furthermore, DLK1-treated mice showed significantly lower levels of fasting and random glucose, with improved glucose and insulin tolerance compared with the vehicle-treated group. Macrophage infiltration and proinflammatory cytokine levels in the epididymal fat were decreased in DLK1-treated db/db mice. Moreover, DLK1 suppressed glucose production from hepatocytes, which was blocked after co-administration of an AMPK inhibitor, compound C. DLK1-treated hepatocytes and mouse liver tissues showed lower PEPCK and G6Pase expression. DLK1 triggered AKT phosphorylation followed by cytosolic translocation of FOXO1 from the nucleus in hepatocytes. CONCLUSIONS The present study demonstrated that exogenous administration of DLK1 reduced hepatic steatosis and hyperglycemia via AMPK activation in the liver. This result suggests that DLK1 may be a novel therapeutic approach for treating NAFLD and diabetes.
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29
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Zwierzina ME, Ejaz A, Bitsche M, Blumer MJF, Mitterberger MC, Mattesich M, Amann A, Kaiser A, Pechriggl EJ, Hörl S, Rostek U, Pierer G, Fritsch H, Zwerschke W. Characterization of DLK1(PREF1)+/CD34+ cells in vascular stroma of human white adipose tissue. Stem Cell Res 2015; 15:403-18. [PMID: 26342195 DOI: 10.1016/j.scr.2015.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/07/2015] [Accepted: 08/13/2015] [Indexed: 02/07/2023] Open
Abstract
Sorting of native (unpermeabilized) SVF-cells from human subcutaneous (s)WAT for cell surface staining (cs) of DLK1 and CD34 identified three main populations: ~10% stained cs-DLK1+/cs-CD34-, ~20% cs-DLK1+/cs-CD34+dim and ~45% cs-DLK1-/cs-CD34+. FACS analysis after permeabilization showed that all these cells stained positive for intracellular DLK1, while CD34 was undetectable in cs-DLK1+/cs-CD34- cells. Permeabilized cs-DLK1-/cs-CD34+ cells were positive for the pericyte marker α-SMA and the mesenchymal markers CD90 and CD105, albeit CD105 staining was dim (cs-DLK1-/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45-/CD31-). Only these cells showed proliferative and adipogenic capacity. Cs-DLK1+/cs-CD34- and cs-DLK1+/cs-CD34+dim cells were also α-SMA+ but expressed CD31, had a mixed hematopoietic and mesenchymal phenotype, and could neither proliferate nor differentiate into adipocytes. Histological analysis of sWAT detected DLK1+/CD34+ and DLK1+/CD90+ cells mainly in the outer ring of vessel-associated stroma and at capillaries. DLK1+/α-SMA+ cells were localized in the CD34- perivascular ring and in adventitial vascular stroma. All these DLK1+ cells possess a spindle-shaped morphology with extremely long processes. DLK1+/CD34+ cells were also detected in vessel endothelium. Additionally, we show that sWAT contains significantly more DLK1+ cells than visceral (v)WAT. We conclude that sWAT has more DKL1+ cells than vWAT and contains different DLK1/CD34 populations, and only cs-DLK1-/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45-/CD31- cells in the adventitial vascular stroma exhibit proliferative and adipogenic capacity.
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Affiliation(s)
- Marit E Zwierzina
- Division for Clinical and Functional Anatomy, Department for Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
| | - Asim Ejaz
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Mario Bitsche
- Division for Clinical and Functional Anatomy, Department for Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
| | - Michael J F Blumer
- Division for Clinical and Functional Anatomy, Department for Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
| | - Maria C Mitterberger
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Monika Mattesich
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Austria
| | - Arno Amann
- Department of Internal Medicine V, Medical University of Innsbruck, Austria
| | - Andreas Kaiser
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Elisabeth J Pechriggl
- Division for Clinical and Functional Anatomy, Department for Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
| | - Susanne Hörl
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Ursula Rostek
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria
| | - Gerhard Pierer
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Austria
| | - Helga Fritsch
- Division for Clinical and Functional Anatomy, Department for Anatomy, Histology and Embryology, Medical University of Innsbruck, Austria
| | - Werner Zwerschke
- Cell Metabolism and Differentiation Research Group, Institute for Biomedical Aging Research, University of Innsbruck, Austria.
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30
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Howard M, Charalambous M. Molecular basis of imprinting disorders affecting chromosome 14: lessons from murine models. Reproduction 2015; 149:R237-49. [DOI: 10.1530/rep-14-0660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Uniparental inheritance of chromosome 14q32 causes developmental failure during gestation and early postnatal development due to mis-expression of a cluster of imprinted genes under common epigenetic control. Two syndromes associated with chromosome 14q32 abnormalities have been described, Kagami–Ogata and Temple syndromes. Both of these syndromes are characterised by specific impairments of intrauterine development, placentation and early postnatal survival. Such abnormalities arise because the processes of intrauterine growth and postnatal adaptation are critically modulated by the dosage of imprinted genes in the chromosome 14q32 cluster. Much of our understanding of how the imprinted genes in this cluster are regulated, as well as their individual functions in the molecular pathways controlling growth and postnatal adaptation, has come from murine models. Mouse chromosome 12qF1 contains an imprinted region syntenic to human chromosome 14q32, collectively referred to as the Dlk1–Dio3 cluster. In this review, we will summarise the wealth of information derived from animal models of chromosome 12 imprinted gene mis-regulation, and explore the relationship between the functions of individual genes and the phenotypic result of their mis-expression. As there is often a considerable overlap between the functions of genes in the Dlk1–Dio3 cluster, we propose that the expression dosage of these genes is controlled by common regulatory mechanisms to co-ordinate the timing of growth and postnatal adaptation. While the diseases associated with mis-regulated chromosome 14 imprinting are rare, studies carried out in mice on the functions of the affected genes as well as their normal regulatory mechanisms have revealed new mechanistic pathways for the control of growth and survival in early life.
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31
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Imprinted genes in myeloid lineage commitment in normal and malignant hematopoiesis. Leukemia 2015; 29:1233-42. [PMID: 25703588 DOI: 10.1038/leu.2015.47] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 01/27/2015] [Accepted: 02/16/2015] [Indexed: 12/12/2022]
Abstract
Genomic imprinting is characterized by the parent-of-origin monoallelic expression of several diploid genes because of epigenetic regulation. Imprinted genes (IGs) are key factors in development, supporting the ability of a genotype to produce phenotypes in response to environmental stimuli. IGs are highly expressed during prenatal stages but are downregulated after birth. They also affect aspects of life other than growth such as cognition, behavior, adaption to novel environments, social dominance and memory consolidation. Deregulated genomic imprinting leads to developmental disorders and is associated with solid and blood cancer as well. Several data have been published highlighting the involvement of IGs in as early as the very small embryonic-like stem cells stage and further during myeloid lineage commitment in normal and malignant hematopoiesis. Therefore, we have assembled the current knowledge on the topic, based mainly on recent findings, trying not to focus on a particular cluster but rather to have a global view of several different IGs in hematopoiesis.
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32
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Comprehensive clinical studies in 34 patients with molecularly defined UPD(14)pat and related conditions (Kagami-Ogata syndrome). Eur J Hum Genet 2015; 23:1488-98. [PMID: 25689926 PMCID: PMC4613461 DOI: 10.1038/ejhg.2015.13] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 01/07/2015] [Accepted: 01/14/2015] [Indexed: 11/08/2022] Open
Abstract
Paternal uniparental disomy 14 (UPD(14)pat) and epimutations and microdeletions affecting the maternally derived 14q32.2 imprinted region lead to a unique constellation of clinical features such as facial abnormalities, small bell-shaped thorax with a coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly, and polyhydramnios. In this study, we performed comprehensive clinical studies in patients with UPD(14)pat (n=23), epimutations (n=5), and microdeletions (n=6), and revealed several notable findings. First, a unique facial appearance with full cheeks and a protruding philtrum and distinctive chest roentgenograms with increased coat-hanger angles to the ribs constituted the pathognomonic features from infancy through childhood. Second, birth size was well preserved, with a median birth length of ±0 SD (range, -1.7 to +3.0 SD) and a median birth weight of +2.3 SD (range, +0.1 to +8.8 SD). Third, developmental delay and/or intellectual disability was invariably present, with a median developmental/intellectual quotient of 55 (range, 29-70). Fourth, hepatoblastoma was identified in three infantile patients (8.8%), and histological examination in two patients showed a poorly differentiated embryonal hepatoblastoma with focal macrotrabecular lesions and well-differentiated hepatoblastoma, respectively. These findings suggest the necessity of an adequate support for developmental delay and periodical screening for hepatoblastoma in the affected patients, and some phenotypic overlap between UPD(14)pat and related conditions and Beckwith-Wiedemann syndrome. On the basis of our previous and present studies that have made a significant contribution to the clarification of underlying (epi)genetic factors and the definition of clinical findings, we propose the name 'Kagami-Ogata syndrome' for UPD(14)pat and related conditions.
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33
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Abdallah BM, Jafari A, Zaher W, Qiu W, Kassem M. Skeletal (stromal) stem cells: an update on intracellular signaling pathways controlling osteoblast differentiation. Bone 2015; 70:28-36. [PMID: 25138551 DOI: 10.1016/j.bone.2014.07.028] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 01/06/2023]
Abstract
Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy for identifying druggable targets for enhancing bone formation. This review will discuss the functions and the molecular mechanisms of action on osteoblast differentiation and bone formation; of a number of recently identified regulatory molecules: the non-canonical Notch signaling molecule Delta-like 1/preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone.
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Affiliation(s)
- Basem M Abdallah
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology, Odense University Hospital & University of Southern Denmark, Odense, Denmark
| | - Abbas Jafari
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology, Odense University Hospital & University of Southern Denmark, Odense, Denmark; DanStem (Danish Stem Cell Center), Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Walid Zaher
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology, Odense University Hospital & University of Southern Denmark, Odense, Denmark; Stem Cell Unit, Department of Anatomy, College of Medicine, King Saud University, Saudi Arabia
| | - Weimin Qiu
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology, Odense University Hospital & University of Southern Denmark, Odense, Denmark
| | - Moustapha Kassem
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology, Odense University Hospital & University of Southern Denmark, Odense, Denmark; DanStem (Danish Stem Cell Center), Panum Institute, University of Copenhagen, Copenhagen, Denmark; Stem Cell Unit, Department of Anatomy, College of Medicine, King Saud University, Saudi Arabia.
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Delta-Like Homologue 1 and Its Role in the Bone Marrow Niche and Hematologic Malignancies. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2014; 14:451-5. [DOI: 10.1016/j.clml.2014.06.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/08/2014] [Accepted: 06/17/2014] [Indexed: 01/08/2023]
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Benetatos L, Vartholomatos G, Hatzimichael E. DLK1-DIO3 imprinted cluster in induced pluripotency: landscape in the mist. Cell Mol Life Sci 2014; 71:4421-30. [PMID: 25098353 PMCID: PMC11113449 DOI: 10.1007/s00018-014-1698-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 12/20/2022]
Abstract
DLK1-DIO3 represents an imprinted cluster which genes are involved in physiological cell biology as early as the stem cell level and in the pathogenesis of several diseases. Transcription factor-mediated induced pluripotent cells (iPSCs) are considered an unlimited source of patient-specific hematopoietic stem cells for clinical application in patient-tailored regenerative medicine. However, to date there is no marker established able to distinguish embryonic stem cell-equivalent iPSCs or safe human iPSCs. Recent findings suggest that the DLK1-DIO3 locus possesses the potential to represent such a marker but there are also contradictory data. This review aims to report the current data on the topic describing both sides of the coin.
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Affiliation(s)
- Leonidas Benetatos
- Blood Bank, Selefkeias 2, Preveza General Hospital, 48100, Preveza, Greece,
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance and obesity, as well as progressive liver dysfunction. Recent animal studies have underscored the importance of hepatic growth hormone (GH) signaling in the development of NAFLD. The imprinted Delta-like homolog 1 (Dlk1)/preadipocyte factor 1 (Pref1) gene encodes a complex protein producing both circulating and membrane-tethered isoforms whose expression dosage is functionally important because even modest elevation during embryogenesis causes lethality. DLK1 is up-regulated during embryogenesis, during suckling, and in the mother during pregnancy. We investigated the normal role for elevated DLK1 dosage by overexpressing Dlk1 from endogenous control elements. This increased DLK1 dosage caused improved glucose tolerance with no primary defect in adipose tissue expansion even under extreme metabolic stress. Rather, Dlk1 overexpression caused reduced fat stores, pituitary insulin-like growth factor 1 (IGF1) resistance, and a defect in feedback regulation of GH. Increased circulatory GH culminated in a switch in whole body fuel metabolism and a reduction in hepatic steatosis. We propose that the function of DLK1 is to shift the metabolic mode of the organism toward peripheral lipid oxidation and away from lipid storage, thus mediating important physiological adaptations associated with early life and with implications for metabolic disease resistance.
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Delta-like 1 homolog (DLK1) inhibits proliferation and myotube formation of avian QM7 myoblasts. Comp Biochem Physiol B Biochem Mol Biol 2014; 179:37-43. [PMID: 25250736 DOI: 10.1016/j.cbpb.2014.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/12/2014] [Accepted: 09/13/2014] [Indexed: 11/23/2022]
Abstract
Delta-like 1 homolog (DLK1) has been implicated as an important regulator in mammalian muscle development. Our previous studies showed that different alternative splicing isoforms have distinct functions in the regulation of myogenesis in mice. Unlike most mammals, including mice, pigs, cattle, and sheep, DLK1 mRNA for avian species has a single form without alternative splicing. In the current study, we have used QM7 cells, a quail myoblast, to study the role of DLK1 in the regulation of avian myogenesis. Overexpression of DLK1 inhibited myogenesis with a lower fusion rate and thinner myotube compared to the control QM7 cells. Comparison of relative levels of protein and mRNA showed down-regulation of PAX7, MYOG, and MHC, and up-regulation of MYOD by DLK1, suggesting that quail DLK1 inhibits myogenesis at later stages of myogenic differentiation and myotube formation. DLK1 reduced the QM7 cell growth rate which is accompanied by a lower percentage of bromodeoxyuridine positive cells, indicating an inhibitory role of DLK1 in proliferation. During the early post-hatch ages, the relatively slower increase in the amount of total DNA mass in breast muscle of the heavy weight quail line, that has been selected for over 40 generations, could be partially explained by the higher expression of DLK1 compared to the control quail. Taken together, DLK1 inhibits myogenic differentiation and proliferation by regulating the expression levels of myogenic factors in quail. In addition, the regulation of expression level and cleavage of full-length DLK1 may be important factors for regulating myogenesis in quail having no splicing variants of DLK1.
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Cleaton MA, Edwards CA, Ferguson-Smith AC. Phenotypic Outcomes of Imprinted Gene Models in Mice: Elucidation of Pre- and Postnatal Functions of Imprinted Genes. Annu Rev Genomics Hum Genet 2014; 15:93-126. [DOI: 10.1146/annurev-genom-091212-153441] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Carol A. Edwards
- Department of Genetics, University of Cambridge, Cambridge CB2 3EG, United Kingdom;
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Peters J. The role of genomic imprinting in biology and disease: an expanding view. Nat Rev Genet 2014; 15:517-30. [PMID: 24958438 DOI: 10.1038/nrg3766] [Citation(s) in RCA: 288] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression according to parental origin. It has long been established that imprinted genes have major effects on development and placental biology before birth. More recently, it has become evident that imprinted genes also have important roles after birth. In this Review, I bring together studies of the effects of imprinted genes from the prenatal period onwards. Recent work on postnatal stages shows that imprinted genes influence an extraordinarily wide-ranging array of biological processes, the effects of which extend into adulthood, and play important parts in common diseases that range from obesity to psychiatric disorders.
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Affiliation(s)
- Jo Peters
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Oxfordshire OX11 0RD, UK
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Stridh P, Ruhrmann S, Bergman P, Thessén Hedreul M, Flytzani S, Beyeen AD, Gillett A, Krivosija N, Öckinger J, Ferguson-Smith AC, Jagodic M. Parent-of-origin effects implicate epigenetic regulation of experimental autoimmune encephalomyelitis and identify imprinted Dlk1 as a novel risk gene. PLoS Genet 2014; 10:e1004265. [PMID: 24676147 PMCID: PMC3967983 DOI: 10.1371/journal.pgen.1004265] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 02/02/2014] [Indexed: 12/17/2022] Open
Abstract
Parent-of-origin effects comprise a range of genetic and epigenetic mechanisms of inheritance. Recently, detection of such effects implicated epigenetic mechanisms in the etiology of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. We here sought to dissect the magnitude and the type of parent-of-origin effects in the pathogenesis of experimental neuroinflammation under controlled environmental conditions. We investigated inheritance of an MS-like disease in rat, experimental autoimmune encephalomyelitis (EAE), using a backcross strategy designed to identify the parental origin of disease-predisposing alleles. A striking 37–54% of all detected disease-predisposing loci depended on parental transmission. Additionally, the Y chromosome from the susceptible strain contributed to disease susceptibility. Accounting for parent-of-origin enabled more powerful and precise identification of novel risk factors and increased the disease variance explained by the identified factors by 2-4-fold. The majority of loci displayed an imprinting–like pattern whereby a gene expressed only from the maternal or paternal copy exerts an effect. In particular, a locus on chromosome 6 comprises a well-known cluster of imprinted genes including the paternally expressed Dlk1, an atypical Notch ligand. Disease-predisposing alleles at the locus conferred lower Dlk1 expression in rats and, together with data from transgenic overexpressing Dlk1 mice, demonstrate that reduced Dlk1 drives more severe disease and modulates adaptive immune reactions in EAE. Our findings suggest a significant epigenetic contribution to the etiology of EAE. Incorporating these effects enables more powerful and precise identification of novel risk factors with diagnostic and prognostic implications for complex disease. Even with recent progress in determining the genetic basis of complex diseases, the issue of ‘missing heritability’ remains and its potential sources are frequently speculated about but rarely explained. Parent-of-origin effects might contribute to the ‘missing heritability’ and involve genetic and epigenetic mechanisms of inheritance. Our study is the first that establishes (i) the magnitude and (ii) the type of parent-of-origin effects in the pathogenesis of a multiple sclerosis-like disease, experimental autoimmune encephalomyelitis (EAE) in rat, using a strategy designed to identify genes that confer risk only when inherited from either mother or father. A striking 37-54% of all risk loci depended on parental origin. Accounting for parent-of-origin enabled more powerful and precise identification of novel risk factors for EAE, such as the imprinted Dlk1gene. Disease-predisposing alleles conferred lower Dlk1 expression in rats and transgenic Dlk1 mice demonstrated that lower Dlk1 drives more severe EAE and modulates adaptive immune responses. Because parental-origin effects are epigenetically regulated, our data implicate a contributory role for epigenetic mechanisms in complex diseases. Considering parent-of-origin effects in complex disease has enabled more powerful and precise identification of novel risk factors.
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Affiliation(s)
- Pernilla Stridh
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Sabrina Ruhrmann
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Petra Bergman
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mélanie Thessén Hedreul
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Sevasti Flytzani
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Amennai Daniel Beyeen
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Alan Gillett
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Nina Krivosija
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Johan Öckinger
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Maja Jagodic
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Reamon-Buettner SM, Buschmann J, Lewin G. Identifying placental epigenetic alterations in an intrauterine growth restriction (IUGR) rat model induced by gestational protein deficiency. Reprod Toxicol 2014; 45:117-24. [PMID: 24607647 DOI: 10.1016/j.reprotox.2014.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/04/2014] [Accepted: 02/26/2014] [Indexed: 12/13/2022]
Abstract
Poor maternal nutrition during gestation can lead to intrauterine growth retardation (IUGR), a main cause of low birth weight associated with high neonatal morbidity and mortality. Such early uterine environmental exposures can impact the neonatal epigenome to render later-in-life disease susceptibility. We established in Wistar Han rats a mild IUGR model induced by gestational protein deficiency (i.e. 9% crude protein in low protein diet vs. 21% in control, from GD 0 to 21) to identify alterations in gene expression and methylation patterns in certain genes implicated in human IUGR or in placental development. We found differential gene expression of Wnt2 and Dlk1 between IUGR and control. Notably, Wnt2 exhibited significant decrease while Dlk1 increase in IUGR placentas, correlating to decrease in fetal and placental weight. Methylation patterns encompassing 30 CpGs in the Wnt2 promoter region revealed variability in both IUGR and control placentas, but a site-specific hypomethylation was evident in IUGR placentas. Our present findings further support a key role of maternal gestational nutrition in defining the neonatal epigenome.
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Affiliation(s)
- Stella Marie Reamon-Buettner
- Toxicology and Environmental Hygiene, Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs Strasse 1, 30625 Hannover, Germany.
| | - Jochen Buschmann
- Toxicology and Environmental Hygiene, Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs Strasse 1, 30625 Hannover, Germany
| | - Geertje Lewin
- Toxicology and Environmental Hygiene, Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs Strasse 1, 30625 Hannover, Germany
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Charalambous M, da Rocha ST, Hernandez A, Ferguson‐Smith AC. Perturbations to the IGF1 growth pathway and adult energy homeostasis following disruption of mouse chromosome 12 imprinting. Acta Physiol (Oxf) 2014; 210:174-87. [PMID: 24034272 PMCID: PMC3992899 DOI: 10.1111/apha.12160] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/10/2013] [Accepted: 08/19/2013] [Indexed: 02/04/2023]
Abstract
Aim Disruption to insulin-like growth factor (IGF) signalling pathways during early life causes growth retardation and defects of developing metabolic organs that can alter set points of energy homeostasis for a lifetime. Inheritance of two maternal copies of human chromosome 14q32.2 (Temple syndrome) causes severe foetal growth retardation and post-natal failure to thrive. Disruption of imprinted gene dosage in the orthologous region on mouse chromosome 12 also affects growth. Here, we investigated whether altering chromosome 12-imprinted gene dosage can affect IGF signalling. Methods We investigated mice with a transgene insertion at the imprinted domain of chromosome 12. This lesion causes misexpression of neighbouring genes such that the expression of non-coding RNAs is elevated, and levels of delta-like homologue 1 (Dlk1), retrotransposon-like 1 (Rtl1) and deiodinase 3 (Dio3) transcripts are reduced. Results We observed three key phenotypes in these mice: (i) embryonic growth retardation associated with altered expression of IGF1 binding proteins, (ii) peri-natal failure to thrive accompanied by hypothyroidism and low serum IGF1. Unexpectedly this phenotype was growth hormone independent. (iii) Adult animals had reduced glucose tolerance as a result of endocrine pancreatic insufficiency. Conclusions We propose that all of these phenotypes are attributable to impaired IGF action and show for the first time that the chromosome 12 cluster in the mouse is an imprinted locus that modulates the IGF signalling pathway. We propose that growth retardation observed in human Temple syndrome might have a similar cause.
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Affiliation(s)
- M. Charalambous
- Department of Physiology, Development and Neuroscience University of Cambridge Cambridge UK
| | - S. T. da Rocha
- Department of Physiology, Development and Neuroscience University of Cambridge Cambridge UK
| | - A. Hernandez
- Maine Medical Center Research Institute Scarborough MEUSA
| | - A. C. Ferguson‐Smith
- Department of Physiology, Development and Neuroscience University of Cambridge Cambridge UK
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Influencing the Social Group. EPIGENETIC SHAPING OF SOCIOSEXUAL INTERACTIONS - FROM PLANTS TO HUMANS 2014; 86:107-34. [DOI: 10.1016/b978-0-12-800222-3.00006-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Dosage-sensitivity of imprinted genes expressed in the brain: 15q11-q13 and neuropsychiatric illness. Biochem Soc Trans 2013; 41:721-6. [PMID: 23697931 DOI: 10.1042/bst20130008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Imprinted genes, those genes subject to parent-of-origin-specific epigenetic marking resulting in monoallelic parent-specific expression, are sensitive to subtle changes in expression dosage. This has been illustrated in a number of experimental models and the fact that both decreased (or complete loss) and increased imprinted gene expression can lead to human diseases. In the present paper, we discuss the consequence of increased dosage of imprinted genes for brain function, focusing on the PWS (Prader-Willi syndrome) locus on human chromosome 15q11-q13 and how predicted increases in dosage of maternally expressed imprinted genes from this interval are associated with a higher risk of developing psychotic illness. The evidence for this comes from individuals with PWS itself and also non-syndromic cases of psychosis in carriers of a maternally derived copy number variant spanning this locus. Of the known imprinted genes in this region, the prime candidate is maternally expressed UBE3A, which encodes E6-AP (E6-associated protein) ubiquitin ligase and has an influence on a number of important neurotransmitter systems. Furthermore, these findings point to the fact that brain function is exquisitely sensitive to both decreases and increases in the expression of imprinted genes.
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Hirasawa R, Matoba S, Inoue K, Ogura A. Somatic donor cell type correlates with embryonic, but not extra-embryonic, gene expression in postimplantation cloned embryos. PLoS One 2013; 8:e76422. [PMID: 24146866 PMCID: PMC3797840 DOI: 10.1371/journal.pone.0076422] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/23/2013] [Indexed: 11/19/2022] Open
Abstract
The great majority of embryos generated by somatic cell nuclear transfer (SCNT) display defined abnormal phenotypes after implantation, such as an increased likelihood of death and abnormal placentation. To gain better insight into the underlying mechanisms, we analyzed genome-wide gene expression profiles of day 6.5 postimplantation mouse embryos cloned from three different cell types (cumulus cells, neonatal Sertoli cells and fibroblasts). The embryos retrieved from the uteri were separated into embryonic (epiblast) and extraembryonic (extraembryonic ectoderm and ectoplacental cone) tissues and were subjected to gene microarray analysis. Genotype- and sex-matched embryos produced by in vitro fertilization were used as controls. Principal component analysis revealed that whereas the gene expression patterns in the embryonic tissues varied according to the donor cell type, those in extraembryonic tissues were relatively consistent across all groups. Within each group, the embryonic tissues had more differentially expressed genes (DEGs) (>2-fold vs. controls) than did the extraembryonic tissues (P<1.0×10–26). In the embryonic tissues, one of the common abnormalities was upregulation of Dlk1, a paternally imprinted gene. This might be a potential cause of the occasional placenta-only conceptuses seen in SCNT-generated mouse embryos (1–5% per embryos transferred in our laboratory), because dysregulation of the same gene is known to cause developmental failure of embryos derived from induced pluripotent stem cells. There were also some DEGs in the extraembryonic tissues, which might explain the poor development of SCNT-derived placentas at early stages. These findings suggest that SCNT affects the embryonic and extraembryonic development differentially and might cause further deterioration in the embryonic lineage in a donor cell-specific manner. This could explain donor cell-dependent variations in cloning efficiency using SCNT.
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Affiliation(s)
| | - Shogo Matoba
- RIKEN BioResouce Center, Tsukuba, Ibaraki, Japan
| | - Kimiko Inoue
- RIKEN BioResouce Center, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Atsuo Ogura
- RIKEN BioResouce Center, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
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Li L, Liu B, Wapinski OL, Tsai MC, Qu K, Zhang J, Carlson JC, Lin M, Fang F, Gupta RA, Helms JA, Chang HY. Targeted disruption of Hotair leads to homeotic transformation and gene derepression. Cell Rep 2013; 5:3-12. [PMID: 24075995 DOI: 10.1016/j.celrep.2013.09.003] [Citation(s) in RCA: 258] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/22/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) are thought to be prevalent regulators of gene expression, but the consequences of lncRNA inactivation in vivo are mostly unknown. Here, we show that targeted deletion of mouse Hotair lncRNA leads to derepression of hundreds of genes, resulting in homeotic transformation of the spine and malformation of metacarpal-carpal bones. RNA sequencing and conditional inactivation reveal an ongoing requirement of Hotair to repress HoxD genes and several imprinted loci such as Dlk1-Meg3 and Igf2-H19 without affecting imprinting choice. Hotair binds to both Polycomb repressive complex 2, which methylates histone H3 at lysine 27 (H3K27), and Lsd1 complex, which demethylates histone H3 at lysine 4 (H3K4) in vivo. Hotair inactivation causes H3K4me3 gain and, to a lesser extent, H3K27me3 loss at target genes. These results reveal the function and mechanisms of Hotair lncRNA in enforcing a silent chromatin state at Hox and additional genes.
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Affiliation(s)
- Lingjie Li
- Howard Hughes Medical Institute and Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Khan QES, Sehic A, Skalleberg N, Landin MA, Khuu C, Risnes S, Osmundsen H. Expression of delta-like 1 homologue and insulin-like growth factor 2 through epigenetic regulation of the genes during development of mouse molar. Eur J Oral Sci 2013; 120:292-302. [PMID: 22813219 DOI: 10.1111/j.1600-0722.2012.00976.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Delta-like 1 homolog (Dlk1) and insulin-like growth factor 2 (Igf2) are two of six well-studied mouse imprinted gene clusters that are paternally expressed. Their expression is also linked to their maternally expressed non-coding RNAs, encoded by Gene trap locus 2 (Gtl2) and Imprinted maternally expressed transcript (H19), co-located as imprinted gene clusters. Using deoxyoligonucleotide microarrays and real-time RT-PCR analysis we showed Dlk1 and Gtl2 to exhibit a time-course of expression during tooth development that was similar to that of Igf2 and H19. Western blot analysis of proteins encoded by Dlk1 and Igf2 suggested that the levels of these proteins reflected those of the corresponding mRNAs. Immunohistochemical studies of DLK1 in murine molars detected the protein in both epithelial and mesenchymal regions, in developing cusp mesenchyme, and in newly synthesized enamel and dentin tubules. IGF2 protein was detected primarily at prenatal stages, suggesting that it may be active before birth. Analysis of methylation of cytosine-phosphate-guanine (CpG) islands in both Dlk1 and Igf2 suggested the presence of an increasing fraction of hypermethylated bases with increasing time of development. The increased levels of hypermethylation coincided both with the diminished levels of expression of Dlk1 and Igf2 and with decreased levels of DLK1 and IGF2 proteins in the tooth germ, suggesting that their expression is regulated via methylation of CpG islands present in these genes.
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Appelbe OK, Yevtodiyenko A, Muniz-Talavera H, Schmidt JV. Conditional deletions refine the embryonic requirement for Dlk1. Mech Dev 2012; 130:143-59. [PMID: 23059197 DOI: 10.1016/j.mod.2012.09.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 09/13/2012] [Accepted: 09/28/2012] [Indexed: 12/21/2022]
Abstract
Numerous studies have implicated Delta-like 1 (DLK1), a transmembrane protein that shares homology with Notch ligands, in embryonic growth and differentiation. Dlk1 expression is widespread, though not ubiquitous, during early development, but is confined to a few specific cell types in adults. Adult Dlk1-expressing tissues include the Insulin-producing β-cells of the pancreas and the Growth hormone-producing somatotrophs of the pituitary gland. Previously generated Dlk1 null mice (Dlk1(Sul-pat)), display a partially penetrant neonatal lethality and a complex pattern of developmental and adult phenotypes. Here we describe the generation of a conditional Dlk1 mouse line (Dlk1(flox)) to facilitate cell type-specific deletion of the Dlk1 gene, providing a powerful system to explore each aspect of the Dlk1 null phenotype. Four tissue-specific Cre mouse lines were used to produce individual Dlk1 deletions in pancreatic β-cells, pituitary somatotrophs and the endothelial cells of the embryo and placenta, key candidates for the Dlk1 phenotype. Contrary to expectations, all of these conditional mice were fully viable, and none recapitulated any aspect of the Dlk1(Sul-pat) null mice. Dlk1 expression is therefore not essential for the normal development of β-cells, somatotrophs and endothelial cells, and the tissues responsible for the Dlk1 null phenotype remain to be identified. Dlk1(flox) mice will continue to provide an important tool for further research into the function of Dlk1.
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Affiliation(s)
- Oliver K Appelbe
- Department of Biological Sciences, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA.
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Tellam RL, Cockett NE, Vuocolo T, Bidwell CA. Genes contributing to genetic variation of muscling in sheep. Front Genet 2012; 3:164. [PMID: 22952470 PMCID: PMC3429854 DOI: 10.3389/fgene.2012.00164] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/10/2012] [Indexed: 12/24/2022] Open
Abstract
Selective breeding programs aiming to increase the productivity and profitability of the sheep meat industry use elite, progeny tested sires. The broad genetic traits of primary interest in the progeny of these sires include skeletal muscle yield, fat content, eating quality, and reproductive efficiency. Natural mutations in sheep that enhance muscling have been identified, while a number of genome scans have identified and confirmed quantitative trait loci (QTL) for skeletal muscle traits. The detailed phenotypic characteristics of sheep carrying these mutations or QTL affecting skeletal muscle show a number of common biological themes, particularly changes in developmental growth trajectories, alterations of whole animal morphology, and a shift toward fast twitch glycolytic fibers. The genetic, developmental, and biochemical mechanisms underpinning the actions of some of these genetic variants are described. This review critically assesses this research area, identifies gaps in knowledge, and highlights mechanistic linkages between genetic polymorphisms and skeletal muscle phenotypic changes. This knowledge may aid the discovery of new causal genetic variants and in some cases lead to the development of biochemical and immunological strategies aimed at enhancing skeletal muscle.
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Affiliation(s)
- Ross L Tellam
- Division of Animal, Food and Health Sciences, Commonwealth Scientific and Industrial Research Organisation St Lucia, QLD, Australia
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50
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A survey of tissue-specific genomic imprinting in mammals. Mol Genet Genomics 2012; 287:621-30. [PMID: 22821278 DOI: 10.1007/s00438-012-0708-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/03/2012] [Indexed: 01/20/2023]
Abstract
In mammals, most somatic cells contain two copies of each autosomal gene, one inherited from each parent. When a gene is expressed, both parental alleles are usually transcribed. However, a subset of genes is subject to the epigenetic silencing of one of the parental copies by genomic imprinting. In this review, we explore the evidence for variability in genomic imprinting between different tissue and cell types. We also consider why the imprinting of particular genes may be restricted to, or lost in, specific tissues and discuss the potential for high-throughput sequencing technologies in facilitating the characterisation of tissue-specific imprinting and assaying the potentially functional variations in epigenetic marks.
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