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Hu P, Hao Y, Tang W, Diering GH, Zou F, Kafri T. Analysis of hepatic lentiviral vector transduction; implications for preclinical studies and clinical gene therapy protocols. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.20.608805. [PMID: 39229157 PMCID: PMC11370356 DOI: 10.1101/2024.08.20.608805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Lentiviral vector-transduced T-cells were approved by the FDA as gene therapy anti-cancer medications. Little is known about the host genetic variation effects on the safety and efficacy of the lentiviral vector gene delivery system. To narrow this knowledge-gap, we characterized hepatic gene delivery by lentiviral vectors across the Collaborative Cross (CC) mouse genetic reference population. For 24 weeks, we periodically measured hepatic luciferase expression from lentiviral vectors in 41 CC mouse strains. Hepatic and splenic vector copy numbers were determined. We report that CC mouse strains showed highly diverse outcomes following lentiviral gene delivery. For the first time, moderate correlation between mouse strain-specific sleeping patterns and transduction efficiency was observed. We associated two quantitative trait loci (QTLs) with intra-strain variations in transduction phenotypes, which mechanistically relates to the phenomenon of metastable epialleles. An additional QTL was associated with the kinetics of hepatic transgene expression. Genes comprised in the above QTLs are potential targets to personalize gene therapy protocols. Importantly, we identified two mouse strains that open new directions in characterizing continuous viral vector silencing and HIV latency. Our findings suggest that wide range patient-specific outcomes of viral vector-based gene therapy should be expected. Thus, novel escalating dose based clinical protocols should be considered.
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2
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Akimova D, Markova T, Ampleeva M, Skoblov M. Variable clinical presentation of split hand/foot malformation syndrome in a family with microduplication of 10q24.32: a case report. Front Genet 2024; 14:1303807. [PMID: 38250576 PMCID: PMC10796452 DOI: 10.3389/fgene.2023.1303807] [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: 09/28/2023] [Accepted: 12/13/2023] [Indexed: 01/23/2024] Open
Abstract
SHFM (Split Hand/Foot Malformation) is a heterogeneous group of disorders characterized by the presence of clefts in the hands and feet, along with syndactyly of the digits. In this article, we describe a family in which two members exhibit characteristic developmental abnormalities associated with SHFM, presenting with variable clinical features. Using whole-genome sequencing, we identified a microduplication of a chromosomal segment on locus 10q24.32, specifically spanning positions 102934495 to 103496555, encompassing genes BTRC, POLL, FBXW4 and LBX1 in the proband. Genomic duplications, including these genes, were previously described in patients diagnosed with the third type of SHFM. We validated the presence of this structural rearrangement in 7 family members, including the proband and the proband's father. Remarkably, further investigation demonstrated that the detected duplication exhibits a mosaic state in the phenotypically normal paternal grandmother of the proband, thereby providing a plausible explanation for the absence of a pathological phenotype in her.
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Affiliation(s)
- Daria Akimova
- Research Centre for Medical Genetics, Moscow, Russia
| | | | - Maria Ampleeva
- Independent Clinical Bioinformatics Laboratory, Moscow, Russia
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3
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Zhou X, Sam TW, Lee AY, Leung D. Mouse strain-specific polymorphic provirus functions as cis-regulatory element leading to epigenomic and transcriptomic variations. Nat Commun 2021; 12:6462. [PMID: 34753915 PMCID: PMC8578388 DOI: 10.1038/s41467-021-26630-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 10/14/2021] [Indexed: 12/27/2022] Open
Abstract
Polymorphic integrations of endogenous retroviruses (ERVs) have been previously detected in mouse and human genomes. While most are inert, a subset can influence the activity of the host genes. However, the molecular mechanism underlying how such elements affect the epigenome and transcriptome and their roles in driving intra-specific variation remain unclear. Here, by utilizing wildtype murine embryonic stem cells (mESCs) derived from distinct genetic backgrounds, we discover a polymorphic MMERGLN (GLN) element capable of regulating H3K27ac enrichment and transcription of neighboring loci. We demonstrate that this polymorphic element can enhance the neighboring Klhdc4 gene expression in cis, which alters the activity of downstream stress response genes. These results suggest that the polymorphic ERV-derived cis-regulatory element contributes to differential phenotypes from stimuli between mouse strains. Moreover, we identify thousands of potential polymorphic ERVs in mESCs, a subset of which show an association between proviral activity and nearby chromatin states and transcription. Overall, our findings elucidate the mechanism of how polymorphic ERVs can shape the epigenome and transcriptional networks that give rise to phenotypic divergence between individuals.
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Affiliation(s)
- Xuemeng Zhou
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, SAR, China
| | - Tsz Wing Sam
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, SAR, China
| | - Ah Young Lee
- Center for Epigenomics Research, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, SAR, China
| | - Danny Leung
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, SAR, China. .,Center for Epigenomics Research, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, SAR, China.
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4
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Bertozzi TM, Becker JL, Blake GET, Bansal A, Nguyen DK, Fernandez-Twinn DS, Ozanne SE, Bartolomei MS, Simmons RA, Watson ED, Ferguson-Smith AC. Variably methylated retrotransposons are refractory to a range of environmental perturbations. Nat Genet 2021; 53:1233-1242. [PMID: 34326545 PMCID: PMC7611517 DOI: 10.1038/s41588-021-00898-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 06/18/2021] [Indexed: 12/27/2022]
Abstract
The agouti viable yellow (Avy) allele is an insertional mutation in the mouse genome caused by a variably methylated intracisternal A particle (VM-IAP) retrotransposon. Avy expressivity is sensitive to a range of early-life chemical exposures and nutritional interventions, suggesting that environmental perturbations can have long-lasting effects on the methylome. However, the extent to which VM-IAP elements are environmentally labile with phenotypic implications is unknown. Using a recently identified repertoire of VM-IAPs, we assessed the epigenetic effects of different environmental contexts. A longitudinal aging analysis indicated that VM-IAPs are stable across the murine lifespan, with only small increases in DNA methylation detected for a subset of loci. No significant effects were observed after maternal exposure to the endocrine disruptor bisphenol A, an obesogenic diet or methyl donor supplementation. A genetic mouse model of abnormal folate metabolism exhibited shifted VM-IAP methylation levels and altered VM-IAP-associated gene expression, yet these effects are likely largely driven by differential targeting by polymorphic KRAB zinc finger proteins. We conclude that epigenetic variability at retrotransposons is not predictive of environmental susceptibility.
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Affiliation(s)
| | | | - Georgina E T Blake
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | - Amita Bansal
- Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Australian National University Medical School, John Curtin School of Medical Research, College of Health and Medicine, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Duy K Nguyen
- Department of Cell and Developmental Biology, Perelman School of Medicine, Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Denise S Fernandez-Twinn
- University of Cambridge Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust Medical Research Council Institute of Metabolic Science, Cambridge, UK
| | - Susan E Ozanne
- University of Cambridge Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust Medical Research Council Institute of Metabolic Science, Cambridge, UK
| | - Marisa S Bartolomei
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca A Simmons
- Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Erica D Watson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | - Anne C Ferguson-Smith
- Department of Genetics, University of Cambridge, Cambridge, UK.
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK.
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5
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Swanzey E, McNamara TF, Apostolou E, Tahiliani M, Stadtfeld M. A Susceptibility Locus on Chromosome 13 Profoundly Impacts the Stability of Genomic Imprinting in Mouse Pluripotent Stem Cells. Cell Rep 2021; 30:3597-3604.e3. [PMID: 32187532 DOI: 10.1016/j.celrep.2020.02.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/21/2020] [Accepted: 02/19/2020] [Indexed: 01/28/2023] Open
Abstract
Cultured pluripotent cells accumulate detrimental chromatin alterations, including DNA methylation changes at imprinted genes known as loss of imprinting (LOI). Although the occurrence of LOI is considered a stochastic phenomenon, here we document a genetic determinant that segregates mouse pluripotent cells into stable and unstable cell lines. Unstable lines exhibit hypermethylation at Dlk1-Dio3 and other imprinted loci, in addition to impaired developmental potential. Stimulation of demethylases by ascorbic acid prevents LOI and loss of developmental potential. Susceptibility to LOI greatly differs between commonly used mouse strains, which we use to map a causal region on chromosome 13 with quantitative trait locus (QTL) analysis. Our observations identify a strong genetic determinant of locus-specific chromatin abnormalities in pluripotent cells and provide a non-invasive way to suppress them. This highlights the importance of considering genetics in conjunction with culture conditions for assuring the quality of pluripotent cells for biomedical applications.
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Affiliation(s)
- Emily Swanzey
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center, NYU Langone Medical Center, New York, NY 10016, USA; Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Thomas F McNamara
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, NY 10016, USA
| | - Effie Apostolou
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Mamta Tahiliani
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, NY 10016, USA; Department of Biology, New York University, New York, NY 10003, USA
| | - Matthias Stadtfeld
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016, USA; Laura and Isaac Perlmutter Cancer Center, NYU Langone Medical Center, New York, NY 10016, USA; Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
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6
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Dissection of the Fgf8 regulatory landscape by in vivo CRISPR-editing reveals extensive intra- and inter-enhancer redundancy. Nat Commun 2021; 12:439. [PMID: 33469032 PMCID: PMC7815712 DOI: 10.1038/s41467-020-20714-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/11/2020] [Indexed: 01/29/2023] Open
Abstract
Developmental genes are often regulated by multiple elements with overlapping activity. Yet, in most cases, the relative function of those elements and their contribution to endogenous gene expression remain poorly characterized. An example of this phenomenon is that distinct sets of enhancers have been proposed to direct Fgf8 in the limb apical ectodermal ridge and the midbrain-hindbrain boundary. Using in vivo CRISPR/Cas9 genome engineering, we functionally dissect this complex regulatory ensemble and demonstrate two distinct regulatory logics. In the apical ectodermal ridge, the control of Fgf8 expression appears distributed between different enhancers. In contrast, we find that in the midbrain-hindbrain boundary, one of the three active enhancers is essential while the other two are dispensable. We further dissect the essential midbrain-hindbrain boundary enhancer to reveal that it is also composed by a mixture of essential and dispensable modules. Cross-species transgenic analysis of this enhancer suggests that its composition may have changed in the vertebrate lineage.
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7
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Bertozzi TM, Elmer JL, Macfarlan TS, Ferguson-Smith AC. KRAB zinc finger protein diversification drives mammalian interindividual methylation variability. Proc Natl Acad Sci U S A 2020; 117:31290-31300. [PMID: 33239447 PMCID: PMC7733849 DOI: 10.1073/pnas.2017053117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Most transposable elements (TEs) in the mouse genome are heavily modified by DNA methylation and repressive histone modifications. However, a subset of TEs exhibit variable methylation levels in genetically identical individuals, and this is associated with epigenetically conferred phenotypic differences, environmental adaptability, and transgenerational epigenetic inheritance. The evolutionary origins and molecular mechanisms underlying interindividual epigenetic variability remain unknown. Using a repertoire of murine variably methylated intracisternal A-particle (VM-IAP) epialleles as a model, we demonstrate that variable DNA methylation states at TEs are highly susceptible to genetic background effects. Taking a classical genetics approach coupled with genome-wide analysis, we harness these effects and identify a cluster of KRAB zinc finger protein (KZFP) genes that modifies VM-IAPs in trans in a sequence-specific manner. Deletion of the cluster results in decreased DNA methylation levels and altered histone modifications at the targeted VM-IAPs. In some cases, these effects are accompanied by dysregulation of neighboring genes. We find that VM-IAPs cluster together phylogenetically and that this is linked to differential KZFP binding, suggestive of an ongoing evolutionary arms race between TEs and this large family of epigenetic regulators. These findings indicate that KZFP divergence and concomitant evolution of DNA binding capabilities are mechanistically linked to methylation variability in mammals, with implications for phenotypic variation and putative paradigms of mammalian epigenetic inheritance.
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Affiliation(s)
- Tessa M Bertozzi
- Department of Genetics, University of Cambridge, CB2 3EH Cambridge, United Kingdom
| | - Jessica L Elmer
- Department of Genetics, University of Cambridge, CB2 3EH Cambridge, United Kingdom
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD 20892
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8
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Vincent E, Villiard E, Sader F, Dhakal S, Kwok BH, Roy S. BMP signaling is essential for sustaining proximo-distal progression in regenerating axolotl limbs. Development 2020; 147:dev.170829. [PMID: 32665245 DOI: 10.1242/dev.170829] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 06/30/2020] [Indexed: 02/04/2023]
Abstract
Amputation of a salamander limb triggers a regeneration process that is perfect. A limited number of genes have been studied in this context and even fewer have been analyzed functionally. In this work, we use the BMP signaling inhibitor LDN193189 on Ambystoma mexicanum to explore the role of BMPs in regeneration. We find that BMP signaling is required for proper expression of various patterning genes and that its inhibition causes major defects in the regenerated limbs. Fgf8 is downregulated when BMP signaling is blocked, but ectopic injection of either human or axolotl protein did not rescue the defects. By administering LDN193189 treatments at different time points during regeneration, we show clearly that limb regeneration progresses in a proximal to distal fashion. This demonstrates that BMPs play a major role in patterning of regenerated limbs and that regeneration is a progressive process like development.
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Affiliation(s)
- Etienne Vincent
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Eric Villiard
- Department of Stomatology, Faculty of Dentistry, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Fadi Sader
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Sabin Dhakal
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, H3T 1J4, Canada
| | - Benjamin H Kwok
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, H3T 1J4, Canada
| | - Stéphane Roy
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada .,Department of Stomatology, Faculty of Dentistry, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
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9
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Strain-Specific Epigenetic Regulation of Endogenous Retroviruses: The Role of Trans-Acting Modifiers. Viruses 2020; 12:v12080810. [PMID: 32727076 PMCID: PMC7472028 DOI: 10.3390/v12080810] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023] Open
Abstract
Approximately 10 percent of the mouse genome consists of endogenous retroviruses (ERVs), relics of ancient retroviral infections that are classified based on their relatedness to exogenous retroviral genera. Because of the ability of ERVs to retrotranspose, as well as their cis-acting regulatory potential due to functional elements located within the elements, mammalian ERVs are generally subject to epigenetic silencing by DNA methylation and repressive histone modifications. The mobilisation and expansion of ERV elements is strain-specific, leading to ERVs being highly polymorphic between inbred mouse strains, hinting at the possibility of the strain-specific regulation of ERVs. In this review, we describe the existing evidence of mouse strain-specific epigenetic control of ERVs and discuss the implications of differential ERV regulation on epigenetic inheritance models. We consider Krüppel-associated box domain (KRAB) zinc finger proteins as likely candidates for strain-specific ERV modifiers, drawing on insights gained from the study of the strain-specific behaviour of transgenes. We conclude by considering the coevolution of KRAB zinc finger proteins and actively transposing ERV elements, and highlight the importance of cross-strain studies in elucidating the mechanisms and consequences of strain-specific ERV regulation.
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10
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Wolf G, de Iaco A, Sun MA, Bruno M, Tinkham M, Hoang D, Mitra A, Ralls S, Trono D, Macfarlan TS. KRAB-zinc finger protein gene expansion in response to active retrotransposons in the murine lineage. eLife 2020; 9:56337. [PMID: 32479262 PMCID: PMC7289599 DOI: 10.7554/elife.56337] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/31/2020] [Indexed: 11/13/2022] Open
Abstract
The Krüppel-associated box zinc finger protein (KRAB-ZFP) family diversified in mammals. The majority of human KRAB-ZFPs bind transposable elements (TEs), however, since most TEs are inactive in humans it is unclear whether KRAB-ZFPs emerged to suppress TEs. We demonstrate that many recently emerged murine KRAB-ZFPs also bind to TEs, including the active ETn, IAP, and L1 families. Using a CRISPR/Cas9-based engineering approach, we genetically deleted five large clusters of KRAB-ZFPs and demonstrate that target TEs are de-repressed, unleashing TE-encoded enhancers. Homozygous knockout mice lacking one of two KRAB-ZFP gene clusters on chromosome 2 and chromosome 4 were nonetheless viable. In pedigrees of chromosome 4 cluster KRAB-ZFP mutants, we identified numerous novel ETn insertions with a modest increase in mutants. Our data strongly support the current model that recent waves of retrotransposon activity drove the expansion of KRAB-ZFP genes in mice and that many KRAB-ZFPs play a redundant role restricting TE activity.
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Affiliation(s)
- Gernot Wolf
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Alberto de Iaco
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ming-An Sun
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Melania Bruno
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Matthew Tinkham
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Don Hoang
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Apratim Mitra
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Sherry Ralls
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
| | - Didier Trono
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, United States
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11
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Ectopic expression of the Stabilin2 gene triggered by an intracisternal A particle (IAP) element in DBA/2J strain of mice. Mamm Genome 2020; 31:2-16. [PMID: 31912264 PMCID: PMC7060167 DOI: 10.1007/s00335-019-09824-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/29/2019] [Indexed: 12/21/2022]
Abstract
Stabilin2 (Stab2) encodes a large transmembrane protein which is predominantly expressed in the liver sinusoidal endothelial cells (LSECs) and functions as a scavenger receptor for various macromolecules including hyaluronans (HA). In DBA/2J mice, plasma HA concentration is ten times higher than in 129S6 or C57BL/6J mice, and this phenotype is genetically linked to the Stab2 locus. Stab2 mRNA in the LSECs was significantly lower in DBA/2J than in 129S6, leading to reduced STAB2 proteins in the DBA/2J LSECs. We found a retrovirus-derived transposable element, intracisternal A particle (IAP), in the promoter region of Stab2DBA which likely interferes with normal expression in the LSECs. In contrast, in other tissues of DBA/2J mice, the IAP drives high ectopic Stab2DBA transcription starting within the 5′ long terminal repeat of IAP in a reverse orientation and continuing through the downstream Stab2DBA. Ectopic transcription requires the Stab2-IAP element but is dominantly suppressed by the presence of loci on 59.7–73.0 Mb of chromosome (Chr) 13 from C57BL/6J, while the same region in 129S6 requires additional loci for complete suppression. Chr13:59.9–73 Mb contains a large number of genes encoding Krüppel-associated box-domain zinc-finger proteins that target transposable elements-derived sequences and repress their expression. Despite the high amount of ectopic Stab2DBA transcript in tissues other than liver, STAB2 protein was undetectable and unlikely to contribute to the plasma HA levels of DBA/2J mice. Nevertheless, the IAP insertion and its effects on the transcription of the downstream Stab2DBA exemplify that stochastic evolutional events could significantly influence susceptibility to complex but common diseases.
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12
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Bruno M, Mahgoub M, Macfarlan TS. The Arms Race Between KRAB–Zinc Finger Proteins and Endogenous Retroelements and Its Impact on Mammals. Annu Rev Genet 2019; 53:393-416. [DOI: 10.1146/annurev-genet-112618-043717] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nearly half of the human genome consists of endogenous retroelements (EREs) and their genetic remnants, a small fraction of which carry the potential to propagate in the host genome, posing a threat to genome integrity and cell/organismal survival. The largest family of transcription factors in tetrapods, the Krüppel-associated box domain zinc finger proteins (KRAB-ZFPs), binds to specific EREs and represses their transcription. Since their first appearance over 400 million years ago, KRAB-ZFPs have undergone dramatic expansion and diversification in mammals, correlating with the invasions of new EREs. In this article we review our current understanding of the structure, function, and evolution of KRAB-ZFPs and discuss growing evidence that the arms race between KRAB-ZFPs and the EREs they target is a major driving force for the evolution of new traits in mammals, often accompanied by domestication of EREs themselves.
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Affiliation(s)
- Melania Bruno
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Mohamed Mahgoub
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Todd S. Macfarlan
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland 20892, USA
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13
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Umair M, Hayat A. Nonsyndromic Split-Hand/Foot Malformation: Recent Classification. Mol Syndromol 2019; 10:243-254. [PMID: 32021595 DOI: 10.1159/000502784] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2019] [Indexed: 01/05/2023] Open
Abstract
Split-hand/foot malformation (SHFM) is a genetic limb anomaly disturbing the central rays of the autopod. SHFM is a genetically heterogeneous disorder with variable expressivity inherited as syndromic and nonsyndromic forms. We provide an update of the clinical and molecular aspects of nonsyndromic SHFM. This rare condition is highly complex due to the clinical variability and irregular genetic inheritance observed in the affected individuals. Nonsyndromic SHFM types have been reviewed in terms of major molecular genetic alterations reported to date. This updated overview will assist researchers, scientists, and clinicians in making an appropriate molecular diagnosis, providing an accurate recurrence risk assessment, and developing a management plan.
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Affiliation(s)
- Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia.,King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,Ministry of National Guard-Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Amir Hayat
- Department of Biochemistry, Faculty of Life and Chemical Sciences, Abdul Wali Khan University, Mardan, Pakistan.,College of Medicine and Health, RILD Wellcome Wolfson Centre, University of Exeter, Royal Devon & Exeter NHS Foundation, Exeter, UK
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14
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Gagnier L, Belancio VP, Mager DL. Mouse germ line mutations due to retrotransposon insertions. Mob DNA 2019; 10:15. [PMID: 31011371 PMCID: PMC6466679 DOI: 10.1186/s13100-019-0157-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
Transposable element (TE) insertions are responsible for a significant fraction of spontaneous germ line mutations reported in inbred mouse strains. This major contribution of TEs to the mutational landscape in mouse contrasts with the situation in human, where their relative contribution as germ line insertional mutagens is much lower. In this focussed review, we provide comprehensive lists of TE-induced mouse mutations, discuss the different TE types involved in these insertional mutations and elaborate on particularly interesting cases. We also discuss differences and similarities between the mutational role of TEs in mice and humans.
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Affiliation(s)
- Liane Gagnier
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dixie L. Mager
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
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15
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Carter TC, Sicko RJ, Kay DM, Browne ML, Romitti PA, Edmunds ZL, Liu A, Fan R, Druschel CM, Caggana M, Brody LC, Mills JL. Copy-number variants and candidate gene mutations in isolated split hand/foot malformation. J Hum Genet 2017; 62:877-884. [PMID: 28539665 PMCID: PMC5612852 DOI: 10.1038/jhg.2017.56] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/19/2017] [Accepted: 04/25/2017] [Indexed: 12/27/2022]
Abstract
Split hand/foot malformation (SHFM) is a congenital limb deficiency with missing or shortened central digits. Some SHFM genes have been identified but the cause of many SHFM cases is unknown. We used single-nucleotide polymorphism (SNP) microarray analysis to detect copy-number variants (CNVs) in 25 SHFM cases without other birth defects from New York State (NYS), prioritized CNVs absent from population CNV databases, and validated these CNVs using quantitative real-time polymerase chain reaction (qPCR). We tested for the validated CNVs in seven cases from Iowa using qPCR, and also sequenced 36 SHFM candidate genes in all the subjects. Seven NYS cases had a potentially deleterious variant: two had a p.R225H or p.R225L mutation in TP63, one had a 17q25 microdeletion, one had a 10q24 microduplication and three had a 17p13.3 microduplication. In addition, one Iowa case had a de novo 10q24 microduplication. The 17q25 microdeletion has not been reported previously in SHFM and included two SHFM candidate genes (SUMO2 and GRB2), while the 10q24 and 17p13.3 CNVs had breakpoints within genomic regions that contained putative regulatory elements and a limb development gene. In SHFM pathogenesis, the microdeletion may cause haploinsufficiency of SHFM genes and/or deletion of their regulatory regions, and the microduplications could disrupt regulatory elements that control transcription of limb development genes.
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Affiliation(s)
- Tonia C. Carter
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B Building, Room 3117, Bethesda, MD 20892, USA
| | - Robert J. Sicko
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12201-2002, USA
| | - Denise M. Kay
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12201-2002, USA
| | - Marilyn L. Browne
- Congenital Malformations Registry, New York State Department of Health, Empire State Plaza-Corning Tower, Albany, NY 12237, USA
- University at Albany School of Public Health, One University Place, Rensselaer, NY 12144, USA
| | - Paul A. Romitti
- Department of Epidemiology, College of Public Health, The University of Iowa, 145 N. Riverside Drive, Iowa City, IA 52242, USA
| | - Zoë L. Edmunds
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12201-2002, USA
| | - Aiyi Liu
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B Building, Room 3117, Bethesda, MD 20892, USA
| | - Ruzong Fan
- Department of Biostatistics, Bioinformatics, and Biomathematics, 4000 Reservoir Road NW, Building D-180, Georgetown University Medical Center, Washington DC 20057, USA
| | - Charlotte M. Druschel
- Congenital Malformations Registry, New York State Department of Health, Empire State Plaza-Corning Tower, Albany, NY 12237, USA
| | - Michele Caggana
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12201-2002, USA
| | - Lawrence C. Brody
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Building 50, 50 South Drive, MSC 8004, Bethesda, MD 20892, USA
| | - James L. Mills
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B Building, Room 3117, Bethesda, MD 20892, USA
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16
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Li CF, Angione K, Milunsky JM. Identification of Critical Region Responsible for Split Hand/Foot Malformation Type 3 (SHFM3) Phenotype through Systematic Review of Literature and Mapping of Breakpoints Using Microarray Data. MICROARRAYS 2015; 5:microarrays5010002. [PMID: 27600068 PMCID: PMC5003447 DOI: 10.3390/microarrays5010002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/03/2015] [Accepted: 12/16/2015] [Indexed: 01/15/2023]
Abstract
Split hand/foot malformation (SHFM) is a limb malformation with underdeveloped or absent central digital rays, clefts of hands and feet, and variable syndactyly of the remaining digits. There are six types of SHFM. Here, we report a boy with SHFM type 3 having normal 4th and 5th digits, absent 2nd and 3rd digits, and a 4th finger flexion deformity, as well as absent 2nd, 3rd and 4th toes bilaterally. His father, two paternal uncles, and two paternal first cousins have similar phenotype. Chromosome analysis showed a normal male karyotype. A 514 kb gain at 10q24.31-q24.32 (chr10:102,962,134-103,476,346, hg19) was identified using 6.0 Single nucleotide polymorphism (SNP) microarray, resulting in the duplication of nine genes, including BTRC and FBXW4. A detailed systematic review of literature and mapping of breakpoints using microarray data from all reported cases in PubMed and DECIPHER were conducted, and exon 1 of BTRC gene was identified as the critical region responsible for the SHFM3 phenotype. The potential mechanism and future studies of this critical region causing the SHFM3 phenotype are discussed.
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Affiliation(s)
| | - Katie Angione
- Center for Human Genetics, Cambridge, MA 02139, USA.
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17
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Friedli M, Trono D. The developmental control of transposable elements and the evolution of higher species. Annu Rev Cell Dev Biol 2015; 31:429-51. [PMID: 26393776 DOI: 10.1146/annurev-cellbio-100814-125514] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transposable elements (TEs) account for at least 50% of the human genome. They constitute essential motors of evolution through their ability to modify genomic architecture, mutate genes and regulate gene expression. Accordingly, TEs are subject to tight epigenetic control during the earliest phases of embryonic development via histone and DNA methylation. Key to this process is recognition by sequence-specific RNA- and protein-based repressors. Collectively, these mediators are responsible for silencing a very broad range of TEs in an evolutionarily dynamic fashion. As a consequence, mobile elements and their controllers exert a marked influence on transcriptional networks in embryonic stem cells and a variety of adult tissues. The emerging picture is not that of a simple arms race but rather of a massive and sophisticated enterprise of TE domestication for the evolutionary benefit of the host.
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Affiliation(s)
- Marc Friedli
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; ,
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; ,
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18
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Lehoczky JA, Thomas PE, Patrie KM, Owens KM, Villarreal LM, Galbraith K, Washburn J, Johnson CN, Gavino B, Borowsky AD, Millen KJ, Wakenight P, Law W, Van Keuren ML, Gavrilina G, Hughes ED, Saunders TL, Brihn L, Nadeau JH, Innis JW. A novel intergenic ETnII-β insertion mutation causes multiple malformations in polypodia mice. PLoS Genet 2013; 9:e1003967. [PMID: 24339789 PMCID: PMC3854779 DOI: 10.1371/journal.pgen.1003967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 10/04/2013] [Indexed: 11/28/2022] Open
Abstract
Mouse early transposon insertions are responsible for ∼10% of spontaneous mutant phenotypes. We previously reported the phenotypes and genetic mapping of Polypodia, (Ppd), a spontaneous, X-linked dominant mutation with profound effects on body plan morphogenesis. Our new data shows that mutant mice are not born in expected Mendelian ratios secondary to loss after E9.5. In addition, we refined the Ppd genetic interval and discovered a novel ETnII-β early transposon insertion between the genes for Dusp9 and Pnck. The ETn inserted 1.6 kb downstream and antisense to Dusp9 and does not disrupt polyadenylation or splicing of either gene. Knock-in mice engineered to carry the ETn display Ppd characteristic ectopic caudal limb phenotypes, showing that the ETn insertion is the Ppd molecular lesion. Early transposons are actively expressed in the early blastocyst. To explore the consequences of the ETn on the genomic landscape at an early stage of development, we compared interval gene expression between wild-type and mutant ES cells. Mutant ES cell expression analysis revealed marked upregulation of Dusp9 mRNA and protein expression. Evaluation of the 5′ LTR CpG methylation state in adult mice revealed no correlation with the occurrence or severity of Ppd phenotypes at birth. Thus, the broad range of phenotypes observed in this mutant is secondary to a novel intergenic ETn insertion whose effects include dysregulation of nearby interval gene expression at early stages of development. Mobile genetic elements, particularly early transposons (ETn), cause malformations by inserting within genes leading to disruption of exons, splicing or polyadenylation. Few mutagenic early transposon insertions have been found outside genes and the effects of such insertions on surrounding gene regulation is poorly understood. We discovered a novel intergenic ETnII-β insertion in the mouse mutant Polypodia (Ppd). We reproduced the mutant phenotype after engineering the mutation in wild-type cells with homologous recombination, proving that this early transposon insertion is Ppd. Mutant mice are not born in expected Mendelian ratios secondary to loss after E9.5. Embryonic stem cells from mutant mice show upregulated transcription of an adjacent gene, Dusp9. Thus, at an early and critical stage of development, dysregulated gene transcription is one consequence of the insertion mutation. DNA methylation of the ETn 5′ LTR is not correlated with phenotypic outcome in mutant mice. Polypodia is an example of an intergenic mobile element insertion in mice causing dramatic morphogenetic defects and fetal death.
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Affiliation(s)
- Jessica A. Lehoczky
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peedikayil E. Thomas
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kevin M. Patrie
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kailey M. Owens
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lisa M. Villarreal
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kenneth Galbraith
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Joe Washburn
- Biomedical Research Core Facilities, DNA Sequencing Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Craig N. Johnson
- Biomedical Research Core Facilities, DNA Sequencing Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bryant Gavino
- Murine Molecular Constructs Laboratory-MMCL Mouse Biology Program, University of California, Davis, California, United States of America
| | - Alexander D. Borowsky
- University of California, Davis, Center for Comparative Medicine and Comprehensive Cancer Center, Department of Pathology and Laboratory Medicine, Davis, California, United States of America
| | - Kathleen J. Millen
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington, United States of America
| | - Paul Wakenight
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington, United States of America
| | - William Law
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Margaret L. Van Keuren
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Galina Gavrilina
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Elizabeth D. Hughes
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Thomas L. Saunders
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lesil Brihn
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Joseph H. Nadeau
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
| | - Jeffrey W. Innis
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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19
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Gurrieri F, Everman DB. Clinical, genetic, and molecular aspects of split-hand/foot malformation: an update. Am J Med Genet A 2013; 161A:2860-72. [PMID: 24115638 DOI: 10.1002/ajmg.a.36239] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 08/26/2013] [Indexed: 12/26/2022]
Abstract
We here provide an update on the clinical, genetic, and molecular aspects of split-hand/foot malformation (SHFM). This rare condition, affecting 1 in 8,500-25,000 newborns, is extremely complex because of its variability in clinical presentation, irregularities in its inheritance pattern, and the heterogeneity of molecular genetic alterations that can be found in affected individuals. Both syndromal and nonsyndromal forms are reviewed and the major molecular genetic alterations thus far reported in association with SHFM are discussed. This updated overview should be helpful for clinicians in their efforts to make an appropriate clinical and genetic diagnosis, provide an accurate recurrence risk assessment, and formulate a management plan.
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Affiliation(s)
- Fiorella Gurrieri
- Istituto di Genetica Medica, Università Cattolica del Sacro Cuore, Rome, Italy
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20
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Jung YD, Ahn K, Kim YJ, Bae JH, Lee JR, Kim HS. Retroelements: molecular features and implications for disease. Genes Genet Syst 2013; 88:31-43. [PMID: 23676708 DOI: 10.1266/ggs.88.31] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Eukaryotic genomes comprise numerous retroelements that have a major impact on the structure and regulation of gene function. Retroelements are regulated by epigenetic controls, and they generate multiple miRNAs that are involved in the induction and progression of genomic instability. Elucidation of the biological roles of retroelements deserves continuous investigation to better understand their evolutionary features and implications for disease.
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Affiliation(s)
- Yi-Deun Jung
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
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21
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Lockwood WW, Chandel SK, Stewart GL, Erdjument-Bromage H, Beverly LJ. The novel ubiquitin ligase complex, SCF(Fbxw4), interacts with the COP9 signalosome in an F-box dependent manner, is mutated, lost and under-expressed in human cancers. PLoS One 2013; 8:e63610. [PMID: 23658844 PMCID: PMC3642104 DOI: 10.1371/journal.pone.0063610] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 04/05/2013] [Indexed: 12/02/2022] Open
Abstract
Identification of novel proteins that can potentially contribute to carcinogenesis is a requisite venture. Herein, we report the first biochemical characterization of the novel F-box and WD40 containing protein, FBXW4. We have identified interacting protein partners and demonstrated that FBXW4 is part of a ubiquitin ligase complex. Furthermore, the Fbxw4 locus is a common site of proviral insertion in a variety of retroviral insertional mutagenesis murine cancer models and Fbxw4 mRNA is highly expressed in the involuting murine mammary gland. To begin to characterize the biochemical function of Fbxw4, we used proteomic analysis to demonstrate that Fbxw4 interacts with Skp1 (SKP1), Cullin1 (CUL1), Ring-box1 (RBX1) and all components of the COP9 signalosome. All of these interactions are dependent on an intact F-box domain of Fbxw4. Furthermore, Fbxw4 is capable of interacting with ubiquitinated proteins within cells in an F-box dependent manner. Finally, we demonstrate that FBXW4 is mutated, lost and under-expressed in a variety of human cancer cell lines and clinical patient samples. Importantly, expression of FBXW4 correlates with survival of patients with non-small cell lung cancer. Taken together, we suggest that FBXW4 may be a novel tumor suppressor that regulates important cellular processes.
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Affiliation(s)
- William W. Lockwood
- Cancer Biology and Genetics Section, Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sahiba K. Chandel
- Department of Medicine, Division of Hematology and Oncology, James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky, United States of America
| | - Greg L. Stewart
- British Columbia Cancer Research Center, Vancouver, British Columbia, Canada
| | - Hediye Erdjument-Bromage
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Levi J. Beverly
- Department of Medicine, Division of Hematology and Oncology, James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
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23
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Rowe HM, Friedli M, Offner S, Verp S, Mesnard D, Marquis J, Aktas T, Trono D. De novo DNA methylation of endogenous retroviruses is shaped by KRAB-ZFPs/KAP1 and ESET. Development 2013; 140:519-29. [PMID: 23293284 DOI: 10.1242/dev.087585] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endogenous retroviruses (ERVs) undergo de novo DNA methylation during the first few days of mammalian embryogenesis, although the factors that control the targeting of this process are largely unknown. We asked whether KAP1 (KRAB-associated protein 1) is involved in this mechanism because of its previously defined role in maintaining the silencing of ERVs through the histone methyltransferase ESET and histone H3 lysine 9 trimethylation. Here, we demonstrate that introduced ERV sequences are sufficient to direct rapid de novo methylation of a flanked promoter in embryonic stem (ES) cells. This mechanism requires the presence of an ERV sequence-recognizing KRAB zinc-finger protein (ZFP) and both KAP1 and ESET. Furthermore, this process can also take place on a strong cellular promoter and leads to methylation signatures that are subsequently maintained in vivo throughout embryogenesis. Finally, we show that methylation of ERVs residing in the genome is affected by knockout of KAP1 in early embryos. KRAB-ZFPs, KAP1 and ESET are thus likely to be responsible for the early embryonic instatement of stable epigenetic marks at ERV-containing loci.
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Affiliation(s)
- Helen M Rowe
- School of Life Sciences and Frontiers in Genetics Program, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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24
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Vlangos CN, Siuniak AN, Robinson D, Chinnaiyan AM, Lyons RH, Cavalcoli JD, Keegan CE. Next-generation sequencing identifies the Danforth's short tail mouse mutation as a retrotransposon insertion affecting Ptf1a expression. PLoS Genet 2013; 9:e1003205. [PMID: 23437000 PMCID: PMC3578742 DOI: 10.1371/journal.pgen.1003205] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 11/14/2012] [Indexed: 11/29/2022] Open
Abstract
The semidominant Danforth's short tail (Sd) mutation arose spontaneously in the 1920s. The homozygous Sd phenotype includes severe malformations of the axial skeleton with an absent tail, kidney agenesis, anal atresia, and persistent cloaca. The Sd mutant phenotype mirrors features seen in human caudal malformation syndromes including urorectal septum malformation, caudal regression, VACTERL association, and persistent cloaca. The Sd mutation was previously mapped to a 0.9 cM region on mouse chromosome 2qA3. We performed Sanger sequencing of exons and intron/exon boundaries mapping to the Sd critical region and did not identify any mutations. We then performed DNA enrichment/capture followed by next-generation sequencing (NGS) of the critical genomic region. Standard bioinformatic analysis of paired-end sequence data did not reveal any causative mutations. Interrogation of reads that had been discarded because only a single end mapped correctly to the Sd locus identified an early transposon (ETn) retroviral insertion at the Sd locus, located 12.5 kb upstream of the Ptf1a gene. We show that Ptf1a expression is significantly upregulated in Sd mutant embryos at E9.5. The identification of the Sd mutation will lead to improved understanding of the developmental pathways that are misregulated in human caudal malformation syndromes. Birth defects are the leading cause of infant mortality in the United States, accounting for 1 in 5 infant deaths annually. Birth defects that affect development of the caudal portion of the embryo can include malformations of the spine, such as spina bifida, and malformations of the kidneys and lower gastrointestinal tract. Little is known regarding the genetic causes of human caudal birth defects. The Danforth's short tail (Sd) mouse shares many similarities with these caudal birth defects that occur in humans. In this manuscript, we used next-generation sequencing to identify the genetic cause of the Sd mouse phenotype. We found that the Sd mutation is a retrotransposon insertion that inappropriately turns on a nearby gene that is normally important for pancreas development. Future studies of Sd mice will help us understand the pathogenesis of caudal birth defects in humans.
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Affiliation(s)
- Christopher N. Vlangos
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Amanda N. Siuniak
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Dan Robinson
- Center for Translational Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Arul M. Chinnaiyan
- Center for Translational Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Robert H. Lyons
- Biological Chemistry Department, University of Michigan, Ann Arbor, Michigan, United States of America
- University of Michigan DNA Sequencing Core, University of Michigan, Ann Arbor, Michigan, United States of America
| | - James D. Cavalcoli
- Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Catherine E. Keegan
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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25
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Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice. PLoS Genet 2013; 9:e1003204. [PMID: 23436999 PMCID: PMC3578775 DOI: 10.1371/journal.pgen.1003204] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 11/14/2012] [Indexed: 11/19/2022] Open
Abstract
Danforth's short tail (Sd) is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney. Caudal regression syndrome (CRS) is a congenital heterogeneous constellation of caudal anomalies that includes varying degrees of agenesis of the spinal column, anorectal malformations, and genitourinary anomalies. Its pathogenesis is unclear. However, it could be the result of excessive physiologic regression of the embryonic caudal region based on analyses of the various mouse mutants carrying caudal agenesis. Among the mouse mutants, the Danforth's short tail (Sd) mouse is considered a best model for human CRS. Sd is a semidominant mutation, characterized by spinal defects, urogenital defects, and anorectal malformations, thus showing phenotypic similarity to human CRS. Although Sd is known to map to mouse chromosome 2, little is known about the molecular nature of the mutation. Here, we demonstrate an insertion of one type of retrotransposon near the Ptf1a gene. This resulted in ectopic expression of Ptf1a gene in the caudal region of the embryo and downregulation of Cdx2 and its downstream targets, leading to characteristic phenotypes in Sd mouse. Thus, Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.
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Abstract
Modifier genes are an integral part of the genetic landscape in both humans and experimental organisms, but have been less well explored in mammals than other systems. A growing number of modifier genes in mouse models of disease nonetheless illustrate the potential for novel findings, while new technical advances promise many more to come. Modifier genes in mouse models include induced mutations and spontaneous or wild-derived variations captured in inbred strains. Identification of modifiers among wild-derived variants in particular should detect disease modifiers that have been shaped by selection and might therefore be compatible with high fitness and function. Here we review selected examples and argue that modifier genes derived from natural variation may provide a bias for nodes in genetic networks that have greater intrinsic plasticity and whose therapeutic manipulation may therefore be more resilient to side effects than conventional targets.
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Affiliation(s)
- Bruce A Hamilton
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America.
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27
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A MusD retrotransposon insertion in the mouse Slc6a5 gene causes alterations in neuromuscular junction maturation and behavioral phenotypes. PLoS One 2012; 7:e30217. [PMID: 22272310 PMCID: PMC3260239 DOI: 10.1371/journal.pone.0030217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 12/15/2011] [Indexed: 11/20/2022] Open
Abstract
Glycine is the major inhibitory neurotransmitter in the spinal cord and some brain regions. The presynaptic glycine transporter, GlyT2, is required for sustained glycinergic transmission through presynaptic reuptake and recycling of glycine. Mutations in SLC6A5, encoding GlyT2, cause hereditary hyperekplexia in humans, and similar phenotypes in knock-out mice, and variants are associated with schizophrenia. We identified a spontaneous mutation in mouse Slc6a5, caused by a MusD retrotransposon insertion. The GlyT2 protein is undetectable in homozygous mutants, indicating a null allele. Homozygous mutant mice are normal at birth, but develop handling-induced spasms at five days of age, and only survive for two weeks, but allow the study of early activity-regulated developmental processes. At the neuromuscular junction, synapse elimination and the switch from embryonic to adult acetylcholine receptor subunits are hastened, consistent with a presumed increase in motor neuron activity, and transcription of acetylcholine receptors is elevated. Heterozygous mice, which show no reduction in lifespan but nonetheless have reduced levels of GlyT2, have a normal thermal sensitivity with the hot-plate test, but differences in repetitive grooming and decreased sleep time with home-cage monitoring. Open-field and elevated plus-maze tests did not detect anxiety-like behaviors; however, the latter showed a hyperactivity phenotype. Importantly, grooming and hyperactivity are observed in mouse schizophrenia models. Thus, mutations in Slc6a5 show changes in neuromuscular junction development as homozygotes, and behavioral phenotypes as heterozygotes, indicating their usefulness for studies related to glycinergic dysfunction.
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Crombach A, Hogeweg P. Is RNA-dependent RNA polymerase essential for transposon control? BMC SYSTEMS BIOLOGY 2011; 5:104. [PMID: 21714914 PMCID: PMC3155503 DOI: 10.1186/1752-0509-5-104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 06/29/2011] [Indexed: 11/29/2022]
Abstract
Background Eukaryotes use RNA interference and RNA-based epigenetic regulation to control transposon activity. In the standard pathways of RNA-based transcriptional and post-transcriptional silencing the protein complex RNA-dependent RNA polymerase (RdRP) plays a crucial role. However, alternative pathways that bypass RdRP have recently been described. Hence two important questions are: is RdRP truly a necessary component for transposon control, and are the alternative RNA-based strategies also capable of controlling transposable elements? Results We have studied the interplay between host RNAi pathways and transposons using mathematical models. We show that the canonical RdRP-based model controls transposons tightly, mainly via the feedback of cytoplasmic small RNA amplification. Next, we consider two variants lacking RdRP and instead employing antisense transcription of transposons. We show that transposon activity is also controlled by the alternative pathways, although cytoplasmic small RNA amplification is absent. Instead, control occurs in the nucleus, through a feedback in the epigenetic regulation. Conclusions Concluding, our models show that the control of transposon activity can be achieved by alternative pathways that lack RdRP and act through different feedback mechanisms. Thus, although RdRP activity is ubiquitous in eukaryotes, it need not be a general requirement for transposon control.
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Affiliation(s)
- Anton Crombach
- Theoretical Biology and Bioinformatics Group, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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Plamondon JA, Harris MJ, Mager DL, Gagnier L, Juriloff DM. The clf2 gene has an epigenetic role in the multifactorial etiology of cleft lip and palate in the A/WySn mouse strain. ACTA ACUST UNITED AC 2011; 91:716-27. [PMID: 21384535 DOI: 10.1002/bdra.20788] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 12/18/2010] [Accepted: 01/13/2011] [Indexed: 11/07/2022]
Abstract
BACKGROUND The A/WySn mouse strain with 15 to 20% penetrance of cleft lip and palate (CLP) is an animal model for human multifactorial CLP. The CLP is due to two unlinked genes that interact epistatically, Wnt9b(clf1) and clf2, plus a maternal effect. The Wnt9b(clf1) mutation is an IAP transposon insertion. The clf2 gene, with unknown function, was located in a 13.6 Mb region of chromosome 13 containing 145 genes. METHODS To reduce the clf2 candidate region, 1146 mice segregating for A/WySn and C57BL/6J alleles at clf2 were screened for recombinants by simple sequence-length polymorphism haplotypes; recombinants' testcross progeny were typed for CLP and simple-sequence length polymorphisms. To identify the function of clf2, the effect of clf2 genotype on risk of CLP was tested in Wnt9b(null/null) knockouts and in compound mutants (Wnt9b(clf1/null) ), and the methylation of the IAP at Wnt9b was assayed in the Wnt9b(clf1/null) mutants by combined bisulfite restriction analysis. RESULTS The location of clf2 was redefined to 3.0 Mb between Cntnap3 and AK029746 containing 48 genes, of which 30 are Zfp genes. The clf2 genotype had no detectable effect on Wnt9b(null/null) embryos, but strongly affected risk of CLP and methylation of the IAP in Wnt9b(clf1/null) embryos. CLP was associated with low levels of methylation of the IAP. CONCLUSIONS The clf2 gene is the first identified polymorphism that affects the epigenetic methylation and silencing of IAP retrotransposons. This CLP model raises the question of whether parallel epigenetic factors are involved in risk and environmental sensitivity of human CLP.
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Affiliation(s)
- Jenna A Plamondon
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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Rowe HM, Trono D. Dynamic control of endogenous retroviruses during development. Virology 2011; 411:273-87. [PMID: 21251689 DOI: 10.1016/j.virol.2010.12.007] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 12/06/2010] [Indexed: 02/07/2023]
Abstract
Close to half of the human genome encompasses mobile genetic elements, most of which are retrotransposons. These genetic invaders are formidable evolutionary forces that have shaped the architecture of the genomes of higher organisms, with some conserving the ability to induce new integrants within their hosts' genome. Expectedly, the control of endogenous retroviruses is tight and multi-pronged. It is most crucially established in the germ line and during the first steps of embryogenesis, primarily through transcriptional mechanisms that have likely evolved under their very pressure, but are now engaged in controlling gene expression at large, notably during early development.
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Affiliation(s)
- Helen M Rowe
- National Program, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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Amsterdam A, Lai K, Komisarczuk AZ, Becker TS, Bronson RT, Hopkins N, Lees JA. Zebrafish Hagoromo mutants up-regulate fgf8 postembryonically and develop neuroblastoma. Mol Cancer Res 2009; 7:841-50. [PMID: 19531571 DOI: 10.1158/1541-7786.mcr-08-0555] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We screened an existing collection of zebrafish insertional mutants for cancer susceptibility by histologic examination of heterozygotes at 2 years of age. As most mutants had no altered cancer predisposition, this provided the first comprehensive description of spontaneous tumor spectrum and frequency in adult zebrafish. Moreover, the screen identified four lines, each carrying a different dominant mutant allele of Hagoromo previously linked to adult pigmentation defects, which develop tumors with high penetrance and that histologically resemble neuroblastoma. These tumors are clearly neural in origin, although they do not express catecholaminergic neuronal markers characteristic of human neuroblastoma. The zebrafish tumors result from inappropriate maintenance of a cell population within the cranial ganglia that are likely neural precursors. These neoplasias typically remain small but they can become highly aggressive, initially traveling along cranial nerves, and ultimately filling the head. The developmental origin of these tumors is highly reminiscent of human neuroblastoma. The four mutant Hagoromo alleles all contain viral insertions in the fbxw4 gene, which encodes an F-box WD40 domain-containing protein. However, although one allele clearly reduced the levels of fbxw4 mRNA, the other three insertions had no detectable effect on fbw4 expression. Instead, we showed that all four mutations result in the postembryonic up-regulation of the neighboring gene, fibroblast growth factor 8 (fgf8). Moreover, fgf8 is highly expressed in the tumorigenic lesions. Although fgf8 overexpression is known to be associated with breast and prostate cancer in mammals, this study provides the first evidence that fgf8 misregulation can lead to neural tumors.
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Affiliation(s)
- Adam Amsterdam
- David H. Koch Institute of Integrative Cancer Research, Cambridge, MA 02139, USA
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Preferential epigenetic suppression of the autonomous MusD over the nonautonomous ETn mouse retrotransposons. Mol Cell Biol 2009; 29:2456-68. [PMID: 19273603 DOI: 10.1128/mcb.01383-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonautonomous retrotransposon subfamilies are often amplified in preference to their coding-competent relatives. However, the mechanisms responsible for such replicative success are poorly understood. Here, we demonstrate that the autonomous MusD long terminal repeat (LTR) retrotransposons are subject to greater epigenetic silencing than their nonautonomous cousins, the early transposons (ETns), which are expressed at a 170-fold-higher level than MusD in mouse embryonic stem (ES) cells. We show that, in ES cells, 5' LTRs and the downstream region of MusD elements are more heavily methylated and are associated with less-activating and more-repressive histone modifications than the highly similar ETnII sequences. The internal region of MusD likely contributes to their silencing, as transgenes with MusD, compared to those with ETnII sequences, show reduced reporter gene expression and a higher level of repressive histone marks. Genomic distribution patterns of MusD and ETn elements are consistent with stronger selection against MusD elements within introns, suggesting that MusD-associated silencing marks can negatively impact genes. We propose a model in which nonautonomous retrotransposons may gain transcriptional and retrotranspositional advantages over their coding-competent counterparts by elimination of the CpG-rich retroviral sequence targeting the autonomous subfamilies for silencing.
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Monaghan JR, Epp LG, Putta S, Page RB, Walker JA, Beachy CK, Zhu W, Pao GM, Verma IM, Hunter T, Bryant SV, Gardiner DM, Harkins TT, Voss SR. Microarray and cDNA sequence analysis of transcription during nerve-dependent limb regeneration. BMC Biol 2009; 7:1. [PMID: 19144100 PMCID: PMC2630914 DOI: 10.1186/1741-7007-7-1] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 01/13/2009] [Indexed: 02/01/2023] Open
Abstract
Background Microarray analysis and 454 cDNA sequencing were used to investigate a centuries-old problem in regenerative biology: the basis of nerve-dependent limb regeneration in salamanders. Innervated (NR) and denervated (DL) forelimbs of Mexican axolotls were amputated and transcripts were sampled after 0, 5, and 14 days of regeneration. Results Considerable similarity was observed between NR and DL transcriptional programs at 5 and 14 days post amputation (dpa). Genes with extracellular functions that are critical to wound healing were upregulated while muscle-specific genes were downregulated. Thus, many processes that are regulated during early limb regeneration do not depend upon nerve-derived factors. The majority of the transcriptional differences between NR and DL limbs were correlated with blastema formation; cell numbers increased in NR limbs after 5 dpa and this yielded distinct transcriptional signatures of cell proliferation in NR limbs at 14 dpa. These transcriptional signatures were not observed in DL limbs. Instead, gene expression changes within DL limbs suggest more diverse and protracted wound-healing responses. 454 cDNA sequencing complemented the microarray analysis by providing deeper sampling of transcriptional programs and associated biological processes. Assembly of new 454 cDNA sequences with existing expressed sequence tag (EST) contigs from the Ambystoma EST database more than doubled (3935 to 9411) the number of non-redundant human-A. mexicanum orthologous sequences. Conclusion Many new candidate gene sequences were discovered for the first time and these will greatly enable future studies of wound healing, epigenetics, genome stability, and nerve-dependent blastema formation and outgrowth using the axolotl model.
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Affiliation(s)
- James R Monaghan
- Department of Biology and Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40506, USA.
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Friedli M, Nikolaev S, Lyle R, Arcangeli M, Duboule D, Spitz F, Antonarakis SE. Characterization of mouse Dactylaplasia mutations: a model for human ectrodactyly SHFM3. Mamm Genome 2008; 19:272-8. [PMID: 18392654 DOI: 10.1007/s00335-008-9106-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 02/19/2008] [Indexed: 11/29/2022]
Abstract
SHFM3 is a limb malformation characterized by the absence of central digits. It has been shown that this condition is associated with tandem duplications of about 500 kb at 10q24. The Dactylaplasia mice display equivalent limb defects and the two corresponding alleles (Dac1j and Dac2j) map in the region syntenic with the duplications in SHFM3. Dac1j was shown to be associated with an insertion of an unspecified ETn-like mouse endogenous transposon upstream of the Fbxw4 gene. Dac2j was also thought to be an insertion or a small inversion in intron 5 of Fbxw4, but the breakpoints and the exact molecular lesion have not yet been characterized. Here we report precise mapping and characterization of these alleles. We failed to identify any copy number differences within the SHFM3 orthologous genomic locus between Dac mutant and wild-type littermates, showing that the Dactylaplasia alleles are not associated with duplications of the region, in contrast with the described human SHFM3 cases. We further show that both Dac1j and Dac2j are caused by insertions of MusD retroelements that share 98% sequence identity. The differences between the nature of the human and mouse genomic abnormalities argue against models proposed so far that either envisioned SHFM3 as a local trisomy or Dac as a mutant allele of Fbxw4. Instead, both genetic conditions might lead to complex alterations of gene regulation mechanisms that would impair limb morphogenesis. Interestingly, the Dac2j mutation occurs within a highly conserved element that may represent a regulatory sequence for a neighboring gene.
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Affiliation(s)
- Marc Friedli
- Department of Genetic Medicine and Development, University of Geneva Medical School and University Hospitals of Geneva, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland
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