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Czapiewski R, Batrakou DG, de Las Heras JI, Carter RN, Sivakumar A, Sliwinska M, Dixon CR, Webb S, Lattanzi G, Morton NM, Schirmer EC. Genomic loci mispositioning in Tmem120a knockout mice yields latent lipodystrophy. Nat Commun 2022; 13:321. [PMID: 35027552 PMCID: PMC8758788 DOI: 10.1038/s41467-021-27869-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 12/19/2021] [Indexed: 12/13/2022] Open
Abstract
Little is known about how the observed fat-specific pattern of 3D-spatial genome organisation is established. Here we report that adipocyte-specific knockout of the gene encoding nuclear envelope transmembrane protein Tmem120a disrupts fat genome organisation, thus causing a lipodystrophy syndrome. Tmem120a deficiency broadly suppresses lipid metabolism pathway gene expression and induces myogenic gene expression by repositioning genes, enhancers and miRNA-encoding loci between the nuclear periphery and interior. Tmem120a-/- mice, particularly females, exhibit a lipodystrophy syndrome similar to human familial partial lipodystrophy FPLD2, with profound insulin resistance and metabolic defects that manifest upon exposure to an obesogenic diet. Interestingly, similar genome organisation defects occurred in cells from FPLD2 patients that harbour nuclear envelope protein encoding LMNA mutations. Our data indicate TMEM120A genome organisation functions affect many adipose functions and its loss may yield adiposity spectrum disorders, including a miRNA-based mechanism that could explain muscle hypertrophy in human lipodystrophy.
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Affiliation(s)
- Rafal Czapiewski
- Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Dzmitry G Batrakou
- Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | | | - Roderick N Carter
- Molecular Metabolism Group, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | | | | | - Charles R Dixon
- Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Shaun Webb
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Giovanna Lattanzi
- CNR - National Research Council of Italy, Institute of Molecular Genetics "Luigi Luca Cavalli-Sforza", Unit of Bologna, Bologna, 40136, Italy
- IRCCS, Istituto Ortopedico Rizzoli, Bologna, 40136, Italy
| | - Nicholas M Morton
- Molecular Metabolism Group, University/BHF Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Eric C Schirmer
- Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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Dixon CR, Malik P, de las Heras JI, Saiz-Ros N, de Lima Alves F, Tingey M, Gaunt E, Richardson AC, Kelly DA, Goldberg MW, Towers GJ, Yang W, Rappsilber J, Digard P, Schirmer EC. STING nuclear partners contribute to innate immune signaling responses. iScience 2021; 24:103055. [PMID: 34541469 PMCID: PMC8436130 DOI: 10.1016/j.isci.2021.103055] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/19/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023] Open
Abstract
STimulator of INterferon Genes (STING) is an adaptor for cytoplasmic DNA sensing by cGAMP/cGAS that helps trigger innate immune responses (IIRs). Although STING is mostly localized in the ER, we find a separate inner nuclear membrane pool of STING that increases mobility and redistributes to the outer nuclear membrane upon IIR stimulation by transfected dsDNA or dsRNA mimic poly(I:C). Immunoprecipitation of STING from isolated nuclear envelopes coupled with mass spectrometry revealed a distinct nuclear envelope-STING proteome consisting of known nuclear membrane proteins and enriched in DNA- and RNA-binding proteins. Seventeen of these nuclear envelope STING partners are known to bind direct interactors of IRF3/7 transcription factors, and testing a subset of these revealed STING partners SYNCRIP, MEN1, DDX5, snRNP70, RPS27a, and AATF as novel modulators of dsDNA-triggered IIRs. Moreover, we find that SYNCRIP is a novel antagonist of the RNA virus, influenza A, potentially shedding light on reports of STING inhibition of RNA viruses.
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Affiliation(s)
- Charles R. Dixon
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Poonam Malik
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Jose I. de las Heras
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Natalia Saiz-Ros
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Flavia de Lima Alves
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Mark Tingey
- Department of Biology, Temple University, Philadelphia 19121, USA
| | - Eleanor Gaunt
- Division of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, UK
| | | | - David A. Kelly
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Martin W. Goldberg
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, UK
| | - Greg J. Towers
- Department of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia 19121, USA
| | - Juri Rappsilber
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
- Department of Bioanalytics, Institute of Biotechnology, Technische Universitat Berlin, 13355 Berlin, Germany
| | - Paul Digard
- Division of Infection and Immunity, Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Eric C. Schirmer
- Institute of Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Mayfield Road, Edinburgh EH9 3BF, UK
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Meinke P, Kerr ARW, Czapiewski R, de Las Heras JI, Dixon CR, Harris E, Kölbel H, Muntoni F, Schara U, Straub V, Schoser B, Wehnert M, Schirmer EC. A multistage sequencing strategy pinpoints novel candidate alleles for Emery-Dreifuss muscular dystrophy and supports gene misregulation as its pathomechanism. EBioMedicine 2019; 51:102587. [PMID: 31862442 PMCID: PMC7000448 DOI: 10.1016/j.ebiom.2019.11.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/18/2019] [Accepted: 11/26/2019] [Indexed: 12/27/2022] Open
Abstract
Background As genome-wide approaches prove difficult with genetically heterogeneous orphan diseases, we developed a new approach to identify candidate genes. We applied this to Emery-Dreifuss muscular dystrophy (EDMD), characterised by early onset contractures, slowly progressive muscular wasting, and life-threatening heart conduction disturbances with wide intra- and inter-familial clinical variability. Roughly half of EDMD patients are linked to six genes encoding nuclear envelope proteins, but the disease mechanism remains unclear because the affected proteins function in both cell mechanics and genome regulation. Methods A primer library was generated to test for mutations in 301 genes from four categories: (I) all known EDMD-linked genes; (II) genes mutated in related muscular dystrophies; (III) candidates generated by exome sequencing in five families; (IV) functional candidates — other muscle nuclear envelope proteins functioning in mechanical/genome processes affected in EDMD. This was used to sequence 56 unlinked patients with EDMD-like phenotype. Findings Twenty-one patients could be clearly assigned: 18 with mutations in genes of similar muscular dystrophies; 3 with previously missed mutations in EDMD-linked genes. The other categories yielded novel candidate genes, most encoding nuclear envelope proteins with functions in gene regulation. Interpretation Our multi-pronged approach identified new disease alleles and many new candidate EDMD genes. Their known functions strongly argue the EDMD pathomechanism is from altered gene regulation and mechanotransduction due to connectivity of candidates from the nuclear envelope to the plasma membrane. This approach highlights the value of testing for related diseases using primer libraries and may be applied for other genetically heterogeneous orphan diseases. Funding The Wellcome Trust, Muscular Dystrophy UK, Medical Research Council, European Community's Seventh Framework Programme “Integrated European –omics research project for diagnosis and therapy in rare neuromuscular and neurodegenerative diseases (NEUROMICS)”.
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Affiliation(s)
- Peter Meinke
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK; Friedrich Baur Institute at the Department of Neurology, University Hospital, LMU Munich, Germany
| | - Alastair R W Kerr
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Rafal Czapiewski
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | | | - Charles R Dixon
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Elizabeth Harris
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Heike Kölbel
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, University College London Great Ormond Street Institute of Child Health, London, UK; 1 NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Ulrike Schara
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Benedikt Schoser
- Friedrich Baur Institute at the Department of Neurology, University Hospital, LMU Munich, Germany
| | - Manfred Wehnert
- Institute of Human Genetics, University of Greifswald (retired), Greifswald, Germany
| | - Eric C Schirmer
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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Capitanchik C, Dixon CR, Swanson SK, Florens L, Kerr ARW, Schirmer EC. Analysis of RNA-Seq datasets reveals enrichment of tissue-specific splice variants for nuclear envelope proteins. Nucleus 2019; 9:410-430. [PMID: 29912636 PMCID: PMC7000147 DOI: 10.1080/19491034.2018.1469351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Laminopathies yield tissue-specific pathologies, yet arise from mutation of ubiquitously-expressed genes. A little investigated hypothesis to explain this is that the mutated proteins or their partners have tissue-specific splice variants. To test this, we analyzed RNA-Seq datasets, finding novel isoforms or isoform tissue-specificity for: Lap2, linked to cardiomyopathy; Nesprin 2, linked to Emery-Dreifuss muscular dystrophy and Lmo7, that regulates the Emery-Dreifuss muscular dystrophy linked emerin gene. Interestingly, the muscle-specific Lmo7 exon is rich in serine phosphorylation motifs, suggesting regulatory function. Muscle-specific splice variants in non-nuclear envelope proteins linked to other muscular dystrophies were also found. Nucleoporins tissue-specific variants were found for Nup54, Nup133, Nup153 and Nup358/RanBP2. RT-PCR confirmed novel Lmo7 and RanBP2 variants and specific knockdown of the Lmo7 variantreduced myogenic index. Nuclear envelope proteins were enriched for tissue-specific splice variants compared to the rest of the genome, suggesting that splice variants contribute to its tissue-specific functions.
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Affiliation(s)
- Charlotte Capitanchik
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Charles R Dixon
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Selene K Swanson
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Laurence Florens
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Alastair R W Kerr
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Eric C Schirmer
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
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Dixon CR, Platani M, Makarov AA, Schirmer EC. Microinjection of Antibodies Targeting the Lamin A/C Histone-Binding Site Blocks Mitotic Entry and Reveals Separate Chromatin Interactions with HP1, CenpB and PML. Cells 2017; 6:cells6020009. [PMID: 28346356 PMCID: PMC5492013 DOI: 10.3390/cells6020009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 02/24/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023] Open
Abstract
Lamins form a scaffold lining the nucleus that binds chromatin and contributes to spatial genome organization; however, due to the many other functions of lamins, studies knocking out or altering the lamin polymer cannot clearly distinguish between direct and indirect effects. To overcome this obstacle, we specifically targeted the mapped histone-binding site of A/C lamins by microinjecting antibodies specific to this region predicting that this would make the genome more mobile. No increase in chromatin mobility was observed; however, interestingly, injected cells failed to go through mitosis, while control antibody-injected cells did. This effect was not due to crosslinking of the lamin polymer, as Fab fragments also blocked mitosis. The lack of genome mobility suggested other lamin-chromatin interactions. To determine what these might be, mini-lamin A constructs were expressed with or without the histone-binding site that assembled into independent intranuclear structures. HP1, CenpB and PML proteins accumulated at these structures for both constructs, indicating that other sites supporting chromatin interactions exist on lamin A. Together, these results indicate that lamin A-chromatin interactions are highly redundant and more diverse than generally acknowledged and highlight the importance of trying to experimentally separate their individual functions.
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Affiliation(s)
- Charles R Dixon
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Melpomeni Platani
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Alexandr A Makarov
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Eric C Schirmer
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
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Dixon CR. Female physicians become mentors for Girl Scouts. W V Med J 1998; 94:76-7. [PMID: 9581506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- C R Dixon
- West Virginia State Medical Association, Charleston, USA
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Mensah EK, Dixon CR. Research review: reimbursement optimization and the quality of multihospital discharge databases. Top Health Inf Manage 1996; 16:72-87. [PMID: 10156204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- E K Mensah
- School of Public Health, University of Illinois at Chicago, USA
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Dixon CR. Assessing allied health data needs. J AHIMA 1995; 66:44-6; quiz 47-8. [PMID: 10141364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Jackson SA, Stirling JM, Dixon CR. A speech-prompted communication aid for the severely handicapped. J Med Eng Technol 1983; 7:88-91. [PMID: 6223142 DOI: 10.3109/03091908309041241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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