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Boczonadi V, Müller JS, Pyle A, Munkley J, Dor T, Quartararo J, Ferrero I, Karcagi V, Giunta M, Polvikoski T, Birchall D, Princzinger A, Cinnamon Y, Lützkendorf S, Piko H, Reza M, Florez L, Santibanez-Koref M, Griffin H, Schuelke M, Elpeleg O, Kalaydjieva L, Lochmüller H, Elliott DJ, Chinnery PF, Edvardson S, Horvath R. EXOSC8 mutations alter mRNA metabolism and cause hypomyelination with spinal muscular atrophy and cerebellar hypoplasia. Nat Commun 2014; 5:4287. [PMID: 24989451 PMCID: PMC4102769 DOI: 10.1038/ncomms5287] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/03/2014] [Indexed: 12/21/2022] Open
Abstract
The exosome is a multi-protein complex, required for the degradation of AU-rich element (ARE) containing messenger RNAs (mRNAs). EXOSC8 is an essential protein of the exosome core, as its depletion causes a severe growth defect in yeast. Here we show that homozygous missense mutations in EXOSC8 cause progressive and lethal neurological disease in 22 infants from three independent pedigrees. Affected individuals have cerebellar and corpus callosum hypoplasia, abnormal myelination of the central nervous system or spinal motor neuron disease. Experimental downregulation of EXOSC8 in human oligodendroglia cells and in zebrafish induce a specific increase in ARE mRNAs encoding myelin proteins, showing that the imbalanced supply of myelin proteins causes the disruption of myelin, and explaining the clinical presentation. These findings show the central role of the exosomal pathway in neurodegenerative disease. The exosome is responsible for mRNA degradation, which is an important step in the regulation of gene expression. Here the authors report that homozygous missense mutations in the exosome subunit, EXOSC8, may cause neurodegenerative disease in infants through the dysregulation of myelin expression.
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Affiliation(s)
- Veronika Boczonadi
- 1] Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK [2]
| | - Juliane S Müller
- 1] Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK [2]
| | - Angela Pyle
- 1] Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK [2]
| | - Jennifer Munkley
- 1] Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK [2]
| | - Talya Dor
- The Monique and Jacques Roboh Department of Genetic Research, Hadassah- Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Jade Quartararo
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11A, Parma 43124, Italy
| | - Ileana Ferrero
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11A, Parma 43124, Italy
| | - Veronika Karcagi
- Department of Molecular Genetics and Diagnostics, NIEH, Albert Florian ut 2-6, Budapest 1097, Hungary
| | - Michele Giunta
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Tuomo Polvikoski
- Department of Pathology, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Daniel Birchall
- Neuroradiology Department, Regional Neurosciences Centre, Queen Victoria Road, Newcastle upon Tyne NE1 4PL, UK
| | - Agota Princzinger
- Department of Paediatrics, Josa Andras Hospital, Szent Istvan utca 6, Nyiregyhaza 4400, Hungary
| | - Yuval Cinnamon
- 1] The Monique and Jacques Roboh Department of Genetic Research, Hadassah- Hebrew University Medical Center, Jerusalem 91120, Israel [2] Department of Poultry and Aquaculture Sciences, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.Box 6, Bet Dagan 50250, Israel
| | - Susanne Lützkendorf
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité-Universitätsmedizin, Charité-Platz 1, 10117 Berlin, Germany
| | - Henriett Piko
- Department of Molecular Genetics and Diagnostics, NIEH, Albert Florian ut 2-6, Budapest 1097, Hungary
| | - Mojgan Reza
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Laura Florez
- Western Australian Institute for Medical Research/Centre for Medical Research, The University of Western Australia, 35 Stirling Highway Crawley, Western Australia 6009 Perth, Australia
| | - Mauro Santibanez-Koref
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Helen Griffin
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Markus Schuelke
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité-Universitätsmedizin, Charité-Platz 1, 10117 Berlin, Germany
| | - Orly Elpeleg
- The Monique and Jacques Roboh Department of Genetic Research, Hadassah- Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Luba Kalaydjieva
- Western Australian Institute for Medical Research/Centre for Medical Research, The University of Western Australia, 35 Stirling Highway Crawley, Western Australia 6009 Perth, Australia
| | - Hanns Lochmüller
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - David J Elliott
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Patrick F Chinnery
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Shimon Edvardson
- The Monique and Jacques Roboh Department of Genetic Research, Hadassah- Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Rita Horvath
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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von Renesse A, Petkova MV, Lützkendorf S, Heinemeyer J, Gill E, Hübner C, von Moers A, Stenzel W, Schuelke M. POMK mutation in a family with congenital muscular dystrophy with merosin deficiency, hypomyelination, mild hearing deficit and intellectual disability. J Med Genet 2014; 51:275-82. [PMID: 24556084 DOI: 10.1136/jmedgenet-2013-102236] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Congenital muscular dystrophies (CMD) with hypoglycosylation of α-dystroglycan are clinically and genetically heterogeneous disorders that are often associated with brain malformations and eye defects. Presently, 16 proteins are known whose dysfunction impedes glycosylation of α-dystroglycan and leads to secondary dystroglycanopathy. OBJECTIVE To identify the cause of CMD with secondary merosin deficiency, hypomyelination and intellectual disability in two siblings from a consanguineous family. METHODS Autozygosity mapping followed by whole exome sequencing and immunochemistry were used to discover and verify a new genetic defect in two siblings with CMD. RESULTS We identified a homozygous missense mutation (c.325C>T, p.Q109*) in protein O-mannosyl kinase (POMK) that encodes a glycosylation-specific kinase (SGK196) required for function of the dystroglycan complex. The protein was absent from skeletal muscle and skin fibroblasts of the patients. In patient muscle, β-dystroglycan was normally expressed at the sarcolemma, while α-dystroglycan failed to do so. Further, we detected co-localisation of POMK with desmin at the costameres in healthy muscle, and a substantial loss of desmin from the patient muscle. CONCLUSIONS Homozygous truncating mutations in POMK lead to CMD with secondary merosin deficiency, hypomyelination and intellectual disability. Loss of desmin suggests that failure of proper α-dystroglycan glycosylation impedes the binding to extracellular matrix proteins and also affects the cytoskeleton.
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Affiliation(s)
- Anja von Renesse
- Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Rajab A, Straub V, McCann LJ, Seelow D, Varon R, Barresi R, Schulze A, Lucke B, Lützkendorf S, Karbasiyan M, Bachmann S, Spuler S, Schuelke M. Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations. PLoS Genet 2010; 6:e1000874. [PMID: 20300641 PMCID: PMC2837386 DOI: 10.1371/journal.pgen.1000874] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 02/05/2010] [Indexed: 11/19/2022] Open
Abstract
We investigated eight families with a novel subtype of congenital generalized lipodystrophy (CGL4) of whom five members had died from sudden cardiac death during their teenage years. ECG studies revealed features of long-QT syndrome, bradycardia, as well as supraventricular and ventricular tachycardias. Further symptoms comprised myopathy with muscle rippling, skeletal as well as smooth-muscle hypertrophy, leading to impaired gastrointestinal motility and hypertrophic pyloric stenosis in some children. Additionally, we found impaired bone formation with osteopenia, osteoporosis, and atlanto-axial instability. Homozygosity mapping located the gene within 2 Mbp on chromosome 17. Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate leading to the detection of homozygous mutations (c.160delG, c.362dupT). PTRF-CAVIN is essential for caveolae biogenesis. These cholesterol-rich plasmalemmal vesicles are involved in signal-transduction and vesicular trafficking and reside primarily on adipocytes, myocytes, and osteoblasts. Absence of PTRF-CAVIN did not influence abundance of its binding partner caveolin-1 and caveolin-3. In patient fibroblasts, however, caveolin-1 failed to localize toward the cell surface and electron microscopy revealed reduction of caveolae to less than 3%. Transfection of full-length PTRF-CAVIN reestablished the presence of caveolae. The loss of caveolae was confirmed by Atomic Force Microscopy (AFM) in combination with fluorescent imaging. PTRF-CAVIN deficiency thus presents the phenotypic spectrum caused by a quintessential lack of functional caveolae. Patients with generalized lipodystrophy have a marked lack of body fat. Several gene defects have been described that impede fat synthesis and maturation of fat cells. Here we report on mutations in a novel gene, called PTRF-CAVIN, causing congenital generalized lipodystrophy type 4 (CGL4) that is additionally associated with muscle disease. Patients' muscles are large but weak and show an involuntary, rolling contraction pattern called “rippling.” Further symptoms comprise life-threatening cardiac arrhythmias and a disorder of bone formation. We searched for shared segments in the genome of seven patients and found the responsible gene, called PTRF-CAVIN, on chromosome 17. This gene is crucial for caveolae (latin for “small caves”) formation. These small indentations of the cell membrane are found on the surface of muscle, bone, fat, and immune cells and facilitate cell-to-cell communication and the absorption of substances from the extracellular space. Patients lack more than 97% of caveolae and artificial insertion of the correct gene into patient skin cells led to the reappearance of caveolae. As cardiac arrhythmia is a severe and potentially life-threatening condition, patients with CGL4 should be closely monitored by ECG and, if necessary, fitted with an implanted pacemaker and cardioverter defibrillator (ICD) device.
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Affiliation(s)
- Anna Rajab
- Genetics Unit, Ministry of Health, Directorate General of Health Affairs, Royal Hospital, Muscat, Oman
| | - Volker Straub
- Institute of Human Genetics, International Center for Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Liza J. McCann
- Department of Rheumatology, Alder Hey Children's Hospital, Liverpool, United Kingdom
| | - Dominik Seelow
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
| | - Raymonda Varon
- Institute of Human Genetics, Charité University Medical School, Berlin, Germany
| | - Rita Barresi
- Institute of Human Genetics, International Center for Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anne Schulze
- Muscle Research Unit, Experimental and Clinical Research Center, Charité University Medical School, Berlin, Germany
| | - Barbara Lucke
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
| | - Susanne Lützkendorf
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
| | - Mohsen Karbasiyan
- Institute of Human Genetics, Charité University Medical School, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité University Medical School, Berlin, Germany
- Core Facility for Electron Microscopy, Charité University Medical School, Berlin, Germany
| | - Simone Spuler
- Muscle Research Unit, Experimental and Clinical Research Center, Charité University Medical School, Berlin, Germany
| | - Markus Schuelke
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
- * E-mail:
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Vidal VPI, Chaboissier MC, Lützkendorf S, Cotsarelis G, Mill P, Hui CC, Ortonne N, Ortonne JP, Schedl A. Sox9 is essential for outer root sheath differentiation and the formation of the hair stem cell compartment. Curr Biol 2006; 15:1340-51. [PMID: 16085486 DOI: 10.1016/j.cub.2005.06.064] [Citation(s) in RCA: 319] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 06/03/2005] [Accepted: 06/21/2005] [Indexed: 12/17/2022]
Abstract
BACKGROUND The mammalian hair represents an unparalleled model system to understand both developmental processes and stem cell biology. The hair follicle consists of several concentric epithelial sheaths with the outer root sheath (ORS) forming the outermost layer. Functionally, the ORS has been implicated in the migration of hair stem cells from the stem cell niche toward the hair bulb. However, factors required for the differentiation of this critical cell lineage remain to be identified. Here, we describe an unexpected role of the HMG-box-containing gene Sox9 in hair development. RESULTS Sox9 expression can be first detected in the epithelial component of the hair placode but then becomes restricted to the outer root sheath (ORS) and the hair stem cell compartment (bulge). Using tissue-specific inactivation of Sox9, we demonstrate that this gene serves a crucial role in hair differentiation and that skin deleted for Sox9 lacks external hair. Strikingly, the ORS acquires epidermal characteristics with ectopic expression of GATA3. Moreover, Sox9 knock hair show severe proliferative defects and the stem cell niche never forms. Finally, we show that Sox9 expression depends on sonic hedgehog (Shh) signaling and demonstrate overexpression in skin tumors in mouse and man. CONCLUSIONS We conclude that although Sox9 is dispensable for hair induction, it directs differentiation of the ORS and is required for the formation of the hair stem cell compartment. Our genetic analysis places Sox9 in a molecular cascade downstream of sonic hedgehog and suggests that this gene is involved in basal cell carcinoma.
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Affiliation(s)
- Valerie P I Vidal
- INSERM U636, Centre de Biochimie, Faculté des Sciences, Parc Valrose, 06108 Nice, France
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Chaboissier MC, Kobayashi A, Vidal VIP, Lützkendorf S, van de Kant HJG, Wegner M, de Rooij DG, Behringer RR, Schedl A. Functional analysis of Sox8 and Sox9 during sex determination in the mouse. Development 2004; 131:1891-901. [PMID: 15056615 DOI: 10.1242/dev.01087] [Citation(s) in RCA: 412] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sex determination in mammals directs an initially bipotential gonad to differentiate into either a testis or an ovary. This decision is triggered by the expression of the sex-determining gene Sry, which leads to the activation of male-specific genes including the HMG-box containing gene Sox9. From transgenic studies in mice it is clear that Sox9 is sufficient to induce testis formation. However, there is no direct confirmation for an essential role for Sox9 in testis determination. The studies presented here are the first experimental proof for an essential role for Sox9 in mediating a switch from the ovarian pathway to the testicular pathway. Using conditional gene targeting, we show that homozygous deletion of Sox9 in XY gonads interferes with sex cord development and the activation of the male-specific markers Mis and P450scc, and leads to the expression of the female-specific markers Bmp2 and follistatin. Moreover, using a tissue specific knock-out approach, we show that Sox9 is involved in Sertoli cell differentiation, the activation of Mis and Sox8, and the inactivation of Sry. Finally, double knock-out analyses suggest that Sox8 reinforces Sox9 function in testis differentiation of mice.
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