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Nayak A, S B A, Bardhan M, Rashmi R, Arunachal G, Prathyusha P, Nalini A, Sathyaprabha T, Udupa K. Evaluation of Cardiac, Autonomic Functions in Ambulant Patients with Duchenne Muscular Dystrophy. SN COMPREHENSIVE CLINICAL MEDICINE 2023; 5:138. [PMID: 37193318 PMCID: PMC10160717 DOI: 10.1007/s42399-023-01473-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 05/18/2023]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder caused by dystrophin gene mutation resulting in muscle weakness, motor delays, difficulty in standing, and inability to walk by 12 years. As disease progresses, it leads to cardiac and respiratory failure. Evaluation of cardiac autonomic status and echocardiography in DMD patients at a young age can be a potential biomarker to assess disease progression. This study aimed to investigate the younger DMD population of 5-11years of age with mild to moderate cardiac involvement for early detection using non-invasive and cost-effective tools. Genetically confirmed male DMD patients, aged 5-11 years (n = 47), screened from the outpatient department of a tertiary neuroscience institution were subjected to heart rate variability and echocardiographic analysis, and values were correlated with their clinical variables. DMD patients showed a significantly higher difference in HR, interventricular septum, E m/s, and E-wave to A-wave (E/A) ratio than normal values (p < 0.001). Significantly higher HR indicates initial sinus tachycardia and decreased IVD (d), and increased E m/s and E/A ratio mark the onset of cardiac symptoms in DMD patients even though its chamber dimension remains normal and are associated with cardiac muscle fibrosis.
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Affiliation(s)
- Amritharekha Nayak
- Department of Neurophysiology, National Institute of Mental Health And Neurosciences (NIMHANS), Hosur Road, Bengaluru, 560029 India
| | - Apoorva S B
- Department of Neurophysiology, National Institute of Mental Health And Neurosciences (NIMHANS), Hosur Road, Bengaluru, 560029 India
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health And Neurosciences (NIMHANS), Bengaluru, 560029 India
| | - R. Rashmi
- Department of Neurophysiology, National Institute of Mental Health And Neurosciences (NIMHANS), Hosur Road, Bengaluru, 560029 India
| | - G. Arunachal
- Department of Human Genetics, National Institute of Mental Health And Neurosciences (NIMHANS), Bengaluru, 560029 India
| | - P.V. Prathyusha
- Department of Biostatistics, National Institute of Mental Health And Neurosciences (NIMHANS), Bengaluru, 560029 India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health And Neurosciences (NIMHANS), Bengaluru, 560029 India
| | - T.N. Sathyaprabha
- Department of Neurophysiology, National Institute of Mental Health And Neurosciences (NIMHANS), Hosur Road, Bengaluru, 560029 India
| | - Kaviraja Udupa
- Department of Neurophysiology, National Institute of Mental Health And Neurosciences (NIMHANS), Hosur Road, Bengaluru, 560029 India
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Oliveira-Santos A, Dagda M, Burkin DJ. Sunitinib inhibits STAT3 phosphorylation in cardiac muscle and prevents cardiomyopathy in the mdx mouse model of Duchenne muscular dystrophy. Hum Mol Genet 2022; 31:2358-2369. [PMID: 35157045 PMCID: PMC9307308 DOI: 10.1093/hmg/ddac042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/31/2022] [Accepted: 02/09/2022] [Indexed: 11/14/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal X-linked genetic disorder affecting approximately 1 in 5000 male births worldwide. DMD is caused by mutations in the dystrophin gene. Dystrophin is essential for maintaining muscle cell membrane integrity and stability by linking the cytoskeleton to the extracellular matrix, which protects myofibers from contraction-induced damage. Loss of dystrophin leads to mechanically induced skeletal and cardiac muscle damage. Although the disease is not evident in DMD patients at birth, muscular dystrophy rapidly progresses and results in respiratory and cardiac muscle failure as early as the teenage years. Premature death in DMD patients is due to cardiac arrhythmias and left ventricular dysfunction. Currently, there is no effective treatment for DMD-related cardiac failure. Recently, we have shown that a Food and Drug Administration-approved small molecule, sunitinib, a multi-targeted tyrosine kinase inhibitor can mitigate skeletal muscle disease through an increase in myogenic capacity, cell membrane integrity, and improvement of skeletal muscle function via regulation of STAT3-related signaling pathway. Chronic activation of STAT3 has been shown to promote cardiac hypertrophy and failure. In this study, we examined the effects of long-term sunitinib treatment on cardiac pathology and function. Our results showed sunitinib treatment reduced STAT3 phosphorylation in the heart muscle of mdx mice, improved cardiac electrical function, increased cardiac output and stroke volume, decreased ventricular hypertrophy, reduced cardiomyocytes membrane damage, fibrotic tissue deposition and slightly decreased cardiac inflammation. Together, our studies support the idea that sunitinib could serve as a novel treatment to slow cardiomyopathy progression in DMD. One Sentence Summary In this study, we determined if sunitinib, a Food and Drug Administration-approved drug, could reduce the pathology and improve cardiac function in an animal model for DMD.
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Affiliation(s)
- Ariany Oliveira-Santos
- Department of Pharmacology, University of Nevada Reno, School of Medicine, Center for Molecular Medicine, Reno NV 89557, USA
| | - Marisela Dagda
- Department of Pharmacology, University of Nevada Reno, School of Medicine, Center for Molecular Medicine, Reno NV 89557, USA
| | - Dean J Burkin
- Department of Pharmacology, University of Nevada Reno, School of Medicine, Center for Molecular Medicine, Reno NV 89557, USA
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3
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Hildyard JCW, Rawson F, Wells DJ, Piercy RJ. Multiplex in situ hybridization within a single transcript: RNAscope reveals dystrophin mRNA dynamics. PLoS One 2020; 15:e0239467. [PMID: 32970731 PMCID: PMC7514052 DOI: 10.1371/journal.pone.0239467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/08/2020] [Indexed: 01/22/2023] Open
Abstract
Dystrophin plays a vital role in maintaining muscle health, yet low mRNA expression, lengthy transcription time and the limitations of traditional in-situ hybridization (ISH) methodologies mean that the dynamics of dystrophin transcription remain poorly understood. RNAscope is highly sensitive ISH method that can be multiplexed, allowing detection of individual transcript molecules at sub-cellular resolution, with different target mRNAs assigned to distinct fluorophores. We instead multiplex within a single transcript, using probes targeted to the 5' and 3' regions of muscle dystrophin mRNA. Our approach shows this method can reveal transcriptional dynamics in health and disease, resolving both nascent myonuclear transcripts and exported mature mRNAs in quantitative fashion (with the latter absent in dystrophic muscle, yet restored following therapeutic intervention). We show that even in healthy muscle, immature dystrophin mRNA predominates (60-80% of total), with the surprising implication that the half-life of a mature transcript is markedly shorter than the time invested in transcription: at the transcript level, supply may exceed demand. Our findings provide unique spatiotemporal insight into the behaviour of this long transcript (with implications for therapeutic approaches), and further suggest this modified multiplex ISH approach is well-suited to long genes, offering a highly tractable means to reveal complex transcriptional dynamics.
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Affiliation(s)
- John C. W. Hildyard
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London, United Kingdom
| | - Faye Rawson
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London, United Kingdom
| | - Dominic J. Wells
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Richard J. Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Science and Services, Royal Veterinary College, London, United Kingdom
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4
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Hildyard JCW, Crawford AH, Rawson F, Riddell DO, Harron RCM, Piercy RJ. Single-transcript multiplex in situ hybridisation reveals unique patterns of dystrophin isoform expression in the developing mammalian embryo. Wellcome Open Res 2020; 5:76. [PMID: 32724863 PMCID: PMC7372313 DOI: 10.12688/wellcomeopenres.15762.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2020] [Indexed: 12/24/2022] Open
Abstract
Background: The dystrophin gene has multiple isoforms: full-length dystrophin (dp427) is principally known for its expression in skeletal and cardiac muscle, but is also expressed in the brain, and several internal promoters give rise to shorter, N-terminally truncated isoforms with wider tissue expression patterns (dp260 in the retina, dp140 in the brain and dp71 in many tissues). These isoforms are believed to play unique cellular roles both during embryogenesis and in adulthood, but their shared sequence identity at both mRNA and protein levels makes study of distinct isoforms challenging by conventional methods. Methods: RNAscope is a novel in-situ hybridisation technique that offers single-transcript resolution and the ability to multiplex, with different target sequences assigned to distinct fluorophores. Using probes designed to different regions of the dystrophin transcript (targeting 5', central and 3' sequences of the long dp427 mRNA), we can simultaneously detect and distinguish multiple dystrophin mRNA isoforms at sub-cellular histological levels. We have used these probes in healthy and dystrophic canine embryos to gain unique insights into isoform expression and distribution in the developing mammal. Results: Dp427 is found in developing muscle as expected, apparently enriched at nascent myotendinous junctions. Endothelial and epithelial surfaces express dp71 only. Within the brain and spinal cord, all three isoforms are expressed in spatially distinct regions: dp71 predominates within proliferating germinal layer cells, dp140 within maturing, migrating cells and dp427 appears within more established cell populations. Dystrophin is also found within developing bones and teeth, something previously unreported, and our data suggests orchestrated involvement of multiple isoforms in formation of these tissues. Conclusions: Overall, shorter isoforms appear associated with proliferation and migration, and longer isoforms with terminal lineage commitment: we discuss the distinct structural contributions and transcriptional demands suggested by these findings.
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Affiliation(s)
- John C. W. Hildyard
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Abbe H. Crawford
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Faye Rawson
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Dominique O. Riddell
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Rachel C. M. Harron
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Richard J. Piercy
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
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5
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Pioner JM, Fornaro A, Coppini R, Ceschia N, Sacconi L, Donati MA, Favilli S, Poggesi C, Olivotto I, Ferrantini C. Advances in Stem Cell Modeling of Dystrophin-Associated Disease: Implications for the Wider World of Dilated Cardiomyopathy. Front Physiol 2020; 11:368. [PMID: 32477154 PMCID: PMC7235370 DOI: 10.3389/fphys.2020.00368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 12/26/2022] Open
Abstract
Familial dilated cardiomyopathy (DCM) is mostly caused by mutations in genes encoding cytoskeletal and sarcomeric proteins. In the pediatric population, DCM is the predominant type of primitive myocardial disease. A severe form of DCM is associated with mutations in the DMD gene encoding dystrophin, which are the cause of Duchenne Muscular Dystrophy (DMD). DMD-associated cardiomyopathy is still poorly understood and orphan of a specific therapy. In the last 5 years, a rise of interest in disease models using human induced pluripotent stem cells (hiPSCs) has led to more than 50 original studies on DCM models. In this review paper, we provide a comprehensive overview on the advances in DMD cardiomyopathy disease modeling and highlight the most remarkable findings obtained from cardiomyocytes differentiated from hiPSCs of DMD patients. We will also describe how hiPSCs based studies have contributed to the identification of specific myocardial disease mechanisms that may be relevant in the pathogenesis of DCM, representing novel potential therapeutic targets.
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Affiliation(s)
- Josè Manuel Pioner
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | | | - Raffaele Coppini
- Department of NeuroFarBa, Università degli Studi di Firenze, Florence, Italy
| | - Nicole Ceschia
- Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Leonardo Sacconi
- LENS, Università degli Studi di Firenze and National Institute of Optics (INO-CNR), Florence, Italy
| | | | - Silvia Favilli
- Pediatric Cardiology, Meyer Children's Hospital, Florence, Italy
| | - Corrado Poggesi
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Iacopo Olivotto
- Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Cecilia Ferrantini
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
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6
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Hildyard JCW, Crawford AH, Rawson F, Riddell DO, Harron RCM, Piercy RJ. Single-transcript multiplex in situ hybridisation reveals unique patterns of dystrophin isoform expression in the developing mammalian embryo. Wellcome Open Res 2020; 5:76. [PMID: 32724863 PMCID: PMC7372313 DOI: 10.12688/wellcomeopenres.15762.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2020] [Indexed: 07/30/2023] Open
Abstract
Background: The dystrophin gene has multiple isoforms: full-length dystrophin (dp427) is principally known for its expression in skeletal and cardiac muscle, but is also expressed in the brain, and several internal promoters give rise to shorter, N-terminally truncated isoforms with wider tissue expression patterns (dp260 in the retina, dp140 in the brain and dp71 in many tissues). These isoforms are believed to play unique cellular roles both during embryogenesis and in adulthood, but their shared sequence identity at both mRNA and protein levels makes study of distinct isoforms challenging by conventional methods. Methods: RNAscope is a novel in-situ hybridisation technique that offers single-transcript resolution and the ability to multiplex, with different target sequences assigned to distinct fluorophores. Using probes designed to different regions of the dystrophin transcript (targeting 5', central and 3' sequences of the long dp427 mRNA), we can simultaneously detect and distinguish multiple dystrophin mRNA isoforms at sub-cellular histological levels. We have used these probes in healthy and dystrophic canine embryos to gain unique insights into isoform expression and distribution in the developing mammal. Results: Dp427 is found in developing muscle as expected, apparently enriched at nascent myotendinous junctions. Endothelial and epithelial surfaces express dp71 only. Within the brain and spinal cord, all three isoforms are expressed in spatially distinct regions: dp71 predominates within proliferating germinal layer cells, dp140 within maturing, migrating cells and dp427 appears within more established cell populations. Dystrophin is also found within developing bones and teeth, something previously unreported, and our data suggests orchestrated involvement of multiple isoforms in formation of these tissues. Conclusions: Overall, shorter isoforms appear associated with proliferation and migration, and longer isoforms with terminal lineage commitment: we discuss the distinct structural contributions and transcriptional demands suggested by these findings.
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Affiliation(s)
- John C. W. Hildyard
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Abbe H. Crawford
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Faye Rawson
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Dominique O. Riddell
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Rachel C. M. Harron
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
| | - Richard J. Piercy
- Department of Clinical Science and Services, Royal Veterinary College, London, Camden, London, NW1 0TU, UK
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7
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Dystrophin Cardiomyopathies: Clinical Management, Molecular Pathogenesis and Evolution towards Precision Medicine. J Clin Med 2018; 7:jcm7090291. [PMID: 30235804 PMCID: PMC6162458 DOI: 10.3390/jcm7090291] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/02/2018] [Accepted: 09/14/2018] [Indexed: 12/16/2022] Open
Abstract
Duchenne’s muscular dystrophy is an X-linked neuromuscular disease that manifests as muscle atrophy and cardiomyopathy in young boys. However, a considerable percentage of carrier females are often diagnosed with cardiomyopathy at an advanced stage. Existing therapy is not disease-specific and has limited effect, thus many patients and symptomatic carrier females prematurely die due to heart failure. Early detection is one of the major challenges that muscular dystrophy patients, carrier females, family members and, research and medical teams face in the complex course of dystrophic cardiomyopathy management. Despite the widespread adoption of advanced imaging modalities such as cardiac magnetic resonance, there is much scope for refining the diagnosis and treatment of dystrophic cardiomyopathy. This comprehensive review will focus on the pertinent clinical aspects of cardiac disease in muscular dystrophy while also providing a detailed consideration of the known and developing concepts in the pathophysiology of muscular dystrophy and forthcoming therapeutic options.
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8
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England J, Loughna S, Rutland CS. Multiple Species Comparison of Cardiac Troponin T and Dystrophin: Unravelling the DNA behind Dilated Cardiomyopathy. J Cardiovasc Dev Dis 2017; 4:E8. [PMID: 29367539 PMCID: PMC5715711 DOI: 10.3390/jcdd4030008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/01/2017] [Accepted: 07/05/2017] [Indexed: 12/14/2022] Open
Abstract
Animals have frequently been used as models for human disorders and mutations. Following advances in genetic testing and treatment options, and the decreasing cost of these technologies in the clinic, mutations in both companion and commercial animals are now being investigated. A recent review highlighted the genes associated with both human and non-human dilated cardiomyopathy. Cardiac troponin T and dystrophin were observed to be associated with both human and turkey (troponin T) and canine (dystrophin) dilated cardiomyopathies. This review gives an overview of the work carried out in cardiac troponin T and dystrophin to date in both human and animal dilated cardiomyopathy.
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Affiliation(s)
- Jennifer England
- School of Life Sciences, Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Siobhan Loughna
- School of Life Sciences, Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Catrin Sian Rutland
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, UK.
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9
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Suh MR, Lee KA, Kim EY, Jung J, Choi WA, Kang SW. Multiplex Ligation-Dependent Probe Amplification in X-linked Recessive Muscular Dystrophy in Korean Subjects. Yonsei Med J 2017; 58:613-618. [PMID: 28332368 PMCID: PMC5368148 DOI: 10.3349/ymj.2017.58.3.613] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are similar genetic disorders whose patterns of mutation and disease phenotypes might be expected to show differences among different countries. We analyzed multiplex ligation-dependent probe amplification (MLPA) data in a large number of Korean patients with DMD/BMD. MATERIALS AND METHODS We obtained 130 positive MLPA results (86 DMD, 27 BMD, and 17 female carriers) from 272 candidates (237 clinically suspected patients and 35 possible female carriers) who took part in this study. We analyzed the mutation patterns among 113 patients diagnosed by MLPA and calculated deletion/duplication percentages from a total of 128 patients, including 15 patients who were diagnosed using methods other than MLPA. We also analyzed hot spot locations among the 130 MLPA-positive results. RESULTS Most mutations were detected in a central hot spot region between exons 44 and 55 (80 samples, 60.6%). Unlike previous reports, a second frequently observed hot spot near the 5'-end was not distinctive. MLPA detected deletions in specific exons in 92 patients with DMD/BMD (71.8%) and duplications in 21 patients (16.4%). CONCLUSION Our MLPA study of a large number of Korean patients with DMD/BMD identified the most frequent mutation hot spot, as well as a unique hot spot pattern. DMD gene mutation patterns do not appear to show significant ethnic differences.
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Affiliation(s)
- Mi Ri Suh
- Department of Rehabilitation Medicine, Gangnam Severance Hospital and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Kyung A Lee
- Department of Laboratory Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Eun Young Kim
- Department of Rehabilitation Medicine, Gangnam Severance Hospital and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Jiho Jung
- Department of Rehabilitation Medicine, Gangnam Severance Hospital and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Won Ah Choi
- Department of Rehabilitation Medicine, Gangnam Severance Hospital and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Woong Kang
- Department of Rehabilitation Medicine, Gangnam Severance Hospital and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea.
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Forsberg LA, Absher D, Dumanski JP. Republished: Non-heritable genetics of human disease: spotlight on post-zygotic genetic variation acquired during lifetime. Postgrad Med J 2014; 89:417-26. [PMID: 23781115 PMCID: PMC3711362 DOI: 10.1136/postgradmedj-2012-101322rep] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The heritability of most common, multifactorial diseases is rather modest and known genetic effects account for a small part of it. The remaining portion of disease aetiology has been conventionally ascribed to environmental effects, with an unknown part being stochastic. This review focuses on recent studies highlighting stochastic events of potentially great importance in human disease—the accumulation of post-zygotic structural aberrations with age in phenotypically normal humans. These findings are in agreement with a substantial mutational load predicted to occur during lifetime within the human soma. A major consequence of these results is that the genetic profile of a single tissue collected at one time point should be used with caution as a faithful portrait of other tissues from the same subject or the same tissue throughout life. Thus, the design of studies in human genetics interrogating a single sample per subject or applying lymphoblastoid cell lines may come into question. Sporadic disorders are common in medicine. We wish to stress the non-heritable genetic variation as a potentially important factor behind the development of sporadic diseases. Moreover, associations between post-zygotic mutations, clonal cell expansions and their relation to cancer predisposition are central in this context. Post-zygotic mutations are amenable to robust examination and are likely to explain a sizable part of non-heritable disease causality, which has routinely been thought of as synonymous with environmental factors. In view of the widespread accumulation of genetic aberrations with age and strong predictions of disease risk from such analyses, studies of post-zygotic mutations may be a fruitful approach for delineation of variants that are causative for common human disorders.
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Affiliation(s)
- Lars Anders Forsberg
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, Uppsala, Sweden
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11
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Capillary electrophoresis for analysis of deletion and duplication in exon 44-55 of Duchenne muscular dystrophy gene. Electrophoresis 2013; 34:2503-10. [DOI: 10.1002/elps.201300207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 05/28/2013] [Accepted: 05/28/2013] [Indexed: 01/30/2023]
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12
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Forsberg LA, Absher D, Dumanski JP. Non-heritable genetics of human disease: spotlight on post-zygotic genetic variation acquired during lifetime. J Med Genet 2013; 50:1-10. [PMID: 23172682 PMCID: PMC3534255 DOI: 10.1136/jmedgenet-2012-101322] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 01/06/2023]
Abstract
The heritability of most common, multifactorial diseases is rather modest and known genetic effects account for a small part of it. The remaining portion of disease aetiology has been conventionally ascribed to environmental effects, with an unknown part being stochastic. This review focuses on recent studies highlighting stochastic events of potentially great importance in human disease-the accumulation of post-zygotic structural aberrations with age in phenotypically normal humans. These findings are in agreement with a substantial mutational load predicted to occur during lifetime within the human soma. A major consequence of these results is that the genetic profile of a single tissue collected at one time point should be used with caution as a faithful portrait of other tissues from the same subject or the same tissue throughout life. Thus, the design of studies in human genetics interrogating a single sample per subject or applying lymphoblastoid cell lines may come into question. Sporadic disorders are common in medicine. We wish to stress the non-heritable genetic variation as a potentially important factor behind the development of sporadic diseases. Moreover, associations between post-zygotic mutations, clonal cell expansions and their relation to cancer predisposition are central in this context. Post-zygotic mutations are amenable to robust examination and are likely to explain a sizable part of non-heritable disease causality, which has routinely been thought of as synonymous with environmental factors. In view of the widespread accumulation of genetic aberrations with age and strong predictions of disease risk from such analyses, studies of post-zygotic mutations may be a fruitful approach for delineation of variants that are causative for common human disorders.
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Affiliation(s)
- Lars Anders Forsberg
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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13
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Juan-Mateu J, Gallano P, Trujillo-Tiebas MJ. Recomendaciones de buena práctica para el diagnóstico genético de las distrofias musculares de Duchenne y de Becker. Med Clin (Barc) 2012; 139:307-12. [DOI: 10.1016/j.medcli.2012.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 01/15/2023]
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14
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Lin YY. Muscle diseases in the zebrafish. Neuromuscul Disord 2012; 22:673-84. [PMID: 22647769 DOI: 10.1016/j.nmd.2012.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/09/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
Abstract
Animal models in biomedical research are important for understanding the pathological mechanisms of human diseases at a molecular and cellular level. Several aspects of mammalian animals, however, may limit their use in modelling neuromuscular disorders. Many attributes of zebrafish (Danio rerio) are complementary to mammalian experimental systems, establishing the zebrafish as a powerful model organism in disease biology. This review focuses on a number of key studies using the zebrafish to model hereditary muscle diseases with additional emphasis on recent advances in zebrafish functional genomics and drug discovery. Increasing research in zebrafish disease models, combined with knowledge from mammalian models, will bring novel insights into the disease pathogenesis of neuromuscular disorders, as well as facilitate the development of effective therapeutic strategies.
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Affiliation(s)
- Yung-Yao Lin
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1HH, United Kingdom.
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Abstract
Somatic mosaicism is the result of postzygotic de novo mutation occurring in a portion of the cells making up an organism. Structural genetic variation is a very heterogeneous group of changes, in terms of numerous types of aberrations that are included in this category, involvement of many mechanisms behind the generation of structural variants, and because structural variation can encompass genomic regions highly variable in size. Structural variation rapidly evolved as the dominating type of changes behind human genetic diversity, and the importance of this variation in biology and medicine is continuously increasing. In this review, we combine the evidence of structural variation in the context of somatic cells. We discuss the normal and disease-related somatic structural variation. We review the recent advances in the field of monozygotic twins and other models that have been studied for somatic mutations, including other vertebrates. We also discuss chromosomal mosaicism in a few prime examples of disease genes that contributed to understanding of the importance of somatic heterogeneity. We further highlight challenges and opportunities related to this field, including methodological and practical aspects of detection of somatic mosaicism. The literature devoted to interindividual variation versus papers reporting on somatic variation suggests that the latter is understudied and underestimated. It is important to increase our awareness about somatic mosaicism, in particular, related to structural variation. We believe that further research of somatic mosaicism will prove beneficial for better understanding of common sporadic disorders.
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Wu Y, Yin G, Fu K, Wu D, Zhai Q, Du H, Huang Z, Niu Y. Gene diagnosis for nine Chinese patients with DMD/BMD by multiplex ligation-dependent probe amplification and prenatal diagnosis for one of them. J Clin Lab Anal 2010; 23:380-6. [PMID: 19927354 DOI: 10.1002/jcla.20349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
This study aims to perform gene diagnosis for nine patients with Duchenne/Becker muscular dystrophy (DMD/BMD) and their parents with multiplex ligation-dependent probe amplification (MLPA), and to carry out prenatal gene diagnosis for one of them. Genomic DNA of the peripheral blood and fetal amniotic fluid cell was extracted from the pedigrees' members with DMD/BMD. Gene diagnosis was performed for theses pedigrees' members using a SALSA KIT. Short tandem repeats (STR) genotyping and X-linkage analysis were performed for the pedigree members of the fetus, which was used in the prenatal diagnosis. MLPA analysis results show that five of nine patients (DMD-1, DMD-2, DMD-4, DMD-8, and DMD-9) with DMD/BMD were found to have several hemizygous exon deletions in the dystrophin gene. The other patients and the fetus did not have any hemizygous deletion or duplication of any exons. The genomic DNA of the fetus was not contaminated by his mother's DNA as identified by STR genotyping. In addition, X-linkage analysis results show that the only X chromosome of the fetus comes from one of his mother's normal X chromosomes. Combined with STR genotyping and X-linkage analysis, MLPA is a convenient, highly effective and reliable gene diagnosis technique for congenital genetic disease.
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Affiliation(s)
- Yupeng Wu
- Anhui Research Institute for Family Planning, Hefei, Anhui, China.
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Hwa HL, Chang YY, Huang CH, Chen CH, Kao YS, Jong YJ, Chao MC, Ko TM. Small Mutations of the DMD Gene in Taiwanese Families. J Formos Med Assoc 2008; 107:463-9. [DOI: 10.1016/s0929-6646(08)60154-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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18
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Takatoh J, Kudoh H, Kondo S, Hanaoka K. Loss of short dystrophin isoform Dp71 in olfactory ensheathing cells causes vomeronasal nerve defasciculation in mouse olfactory system. Exp Neurol 2008; 213:36-47. [PMID: 18586242 DOI: 10.1016/j.expneurol.2008.04.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 04/14/2008] [Accepted: 04/20/2008] [Indexed: 10/22/2022]
Abstract
The Duchenne muscular dystrophy (DMD) gene encodes dystrophin, which is a protein defective in DMD patients, as well as a number of shorter isoforms, which have been shown to be expressed in various non-muscle, primarily neural, tissues. As of yet, the physiological function of the various dystrophin isoforms is not fully understood. In the present study, we investigated the neurological phenotype that arises in the DMD-null mice, where expression of all dystrophin isoforms had been disrupted. We demonstrate that vomeronasal axons in the DMD-null mice are defasciculated, and some of the defasciculated vomeronasal axons aberrantly entered into the main olfactory bulb, which indicates that the product(s) of the DMD gene plays an important role in vomeronasal nerve organization. Through western blot and immunofluorescence analyses, we determined that the dystrophin isoform Dp71 was exclusively expressed in the mouse olfactory system: mainly in the olfactory ensheathing cells (OECs), an olfactory system-specific glia cell that ensheaths fascicles of the olfactory nerve. In the OECs, Dp71 was co-localized with beta-dystroglycan, utrophin, laminin, and perlecan. Since beta-dystroglycan and perlecan expression was decreased in the OECs of DMD-null mice, we hypothesize that Dp71 expressed in the OECs participates in fasciculation of the vomeronasal nerve, most likely through interactions with extracellular matrix.
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Affiliation(s)
- Jun Takatoh
- Laboratory of Molecular Embryology, Department of Bioscience, Kitasato University School of Science, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan
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Wang X, Wang Z, Yan M, Huang S, Chen TJ, Zhong N. Similarity of DMD gene deletion and duplication in the Chinese patients compared to global populations. Behav Brain Funct 2008; 4:20. [PMID: 18445268 PMCID: PMC2386868 DOI: 10.1186/1744-9081-4-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/29/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND DNA deletion and duplication were determined as the major mutation underlying Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). METHOD Applying multiplex ligation-dependent probe amplification (MLPA), we have analyzed 179 unrelated DMD/BMD subjects from northern China. RESULTS Seventy-three percent of the subjects were found having a deletion (66.25%) or duplication (6.25%). Exons 51-52 were detected as the most common fragment deleted in single-exon deletion, and the region of exons 45-50 was the most common exons deleted in multi-exon deletions. About 90% of DMD/BMD cases carry a small size deletion that involves 10 exons or less, 26.67% of which carry a single-exon deletion. Most of the smaller deletions resulted in an out-of-frame mutation. The most common exons deleted were determined to be between exon 48 and exon 52, with exon 50 was the model allele. Verifying single-exon deletion, one sample with a deletion of exon 53 that was initially observed from MLPA showed that there was a single base deletion that abolished the ligation site in MLPA. Confirmation of single-exon deletion is recommended to exclude single base deletion or mutation at the MLPA ligation site. CONCLUSION The frequency of deletion and duplication in northern China is similar to global ethnic populations.
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Affiliation(s)
- Xiaozhu Wang
- Peking University Center of Medical Genetics, Peking University, Beijing, China.
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20
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Hwa HL, Chang YY, Chen CH, Kao YS, Jong YJ, Chao MC, Ko TM. Multiplex Ligation-dependent Probe Amplification Identification of Deletions and Duplications of the Duchenne Muscular Dystrophy Gene in Taiwanese Subjects. J Formos Med Assoc 2007; 106:339-46. [PMID: 17561468 DOI: 10.1016/s0929-6646(09)60318-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND/PURPOSE Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive disorders caused by mutations in the DMD gene. We intended to determine the distribution of DMD gene deletions and duplications in local Taiwanese male patients and potential female carriers. METHODS A total of 102 unrelated subjects, including 89 unrelated DMD/BMD male patients and another 13 unrelated potential female carriers, were recruited for this study. Multiplex ligation-dependent probe amplification (MLPA) was employed to detect DMD gene deletions and duplications in the 102 subjects. RESULTS MLPA was informative in 60.7% (54/89) of these patients, identifying deletions in 36.0% (32/89) and duplications in 24.7% (22/89) of these patients. This assay revealed deletions in 30.8% (4/13) and duplications in 30.8% (4/13) of the 13 potential carriers. Deletions and duplications were detected in 35.3% (36/102) and 25.5% (26/102) of a total of 102 affected families, respectively in this series. The "hotspot" regions of the duplications were close to those of the deletions. CONCLUSION MLPA was proven to be a powerful tool for the detection of DMD gene deletions and duplications in male patients and female carriers. There was a relatively lower frequency of deletion and a higher frequency of duplication of DMD gene in this population compared to previous reports.
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Affiliation(s)
- Hsiao-Lin Hwa
- Department of Obstetrics and Gynecology, National Taiwan University Hospital, and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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Gatta V, Scarciolla O, Gaspari AR, Palka C, De Angelis MV, Di Muzio A, Guanciali-Franchi P, Calabrese G, Uncini A, Stuppia L. Identification of deletions and duplications of the DMD gene in affected males and carrier females by multiple ligation probe amplification (MLPA). Hum Genet 2005; 117:92-8. [PMID: 15841391 DOI: 10.1007/s00439-005-1270-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 01/13/2005] [Indexed: 11/30/2022]
Abstract
Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused in the majority of cases by deletions of the DMD gene and are readily detectable in affected males by multiplex polymerase chain reaction (PCR). However, different approaches must be used for the identification of female carriers, in which deletions are not detectable by PCR, because of the presence of a normal X chromosome. In this study, we used the multiple ligation probe amplification (MLPA) tool for the identification of female carriers of DMD deletions or duplications in 12 families with a single affected male, 10 of which were previously diagnosed as carriers of a DMD rearrangement, and the remaining two as having an unknown disease-causing mutation. In all the investigated affected males, MLPA analysis confirmed the presence of a DMD rearrangement, and in six of them allowed the refinement of the breakpoints. In 12 female relatives of the affected patients, MLPA analysis showed a DMD deletion or duplication, confirming their carrier status. Two of these were the mother and the sister of a patient whose disease-causing mutation was not known. MLPA analysis thus proved to be an useful tool for the analysis of both affected males and females carriers of DMD rearrangements in cases in which the disease-causing mutation in the affected male was not known, providing useful information for the genetic counselling of the family.
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Affiliation(s)
- Valentina Gatta
- Department of Biomedical Sciences, G. D'Annunzio University Foundation, Chieti, Italy
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22
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Kudoh H, Ikeda H, Kakitani M, Ueda A, Hayasaka M, Tomizuka K, Hanaoka K. A new model mouse for Duchenne muscular dystrophy produced by 2.4 Mb deletion of dystrophin gene using Cre-loxP recombination system. Biochem Biophys Res Commun 2005; 328:507-16. [PMID: 15694376 DOI: 10.1016/j.bbrc.2004.12.191] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2004] [Indexed: 11/28/2022]
Abstract
Duchenne muscular dystrophy (DMD) is caused by mutation in the 2.4-Mb dystrophin (DMD) gene . This gene encodes a number of tissue-specific isoforms of dystrophin generated by transcription from at least seven promoters and also by alternative splicing. We deleted entire genomic region of the DMD gene on mouse chromosome X using a Cre-loxP recombination system. Introduction of a loxP site in dystrophin's first and last exon by homologous recombination in mouse embryonic stem (ES) cells generated "DMD-floxed" (flanked by loxP sites) ES cells, which we subjected to Cre-mediated excision leading to establishment of "DMD-null" ES cell lines. The DMD-null mice produced from the DMD-null ES cells were viable but displayed severe muscular hypertrophy and dystrophy. In addition to the muscular impairment, the DMD-null mouse exhibited some behavioral abnormality and male sterility. The DMD-floxed mice produced from the DMD-floxed ES cells were viable, phenotypically normal, and were born with the expected Mendelian frequency, despite the absence of brain (cortical)-type dystrophin (Dp427c) expression. Since production of multiple dystrophin isoforms due to alternative splicing or exon skipping is totally prevented in the DMD-null mouse, these new mutants will provide an improved model system for functional studies of dystrophin and its isoforms.
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Affiliation(s)
- Hiroe Kudoh
- Laboratory of Molecular Embryology, Department of Bioscience, Kitasato University School of Science, Sagamihara, Kanagawa 228-8555, Japan
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23
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Sawada H, Kikukawa Y, Ban S, Kakudo T, Yokosawa H. Expression of trypsin-like proteases and protease nexin-1 in mdx mouse muscles. Biochem Biophys Res Commun 2004; 314:654-8. [PMID: 14733957 DOI: 10.1016/j.bbrc.2003.12.143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In order to examine the possible participation of trypsin-like proteases in the onset and progress of muscular dystrophy, we investigated the expression of the trypsin-like protease in muscular tissues in mdx mice. We found that the mRNAs of several trypsin-like proteases, including hepsin and t-PA, were expressed in the muscular tissues of mdx mice, but at levels not significantly different from normal mice. Since the enzymatic properties of dystrypsin, a muscle trypsin-like protease activated before onset of the disease, are similar to those of thrombin, we investigated the expression pattern of thrombin in mdx mouse muscles. The results showed that prothrombin mRNA is up-regulated in mdx mice at 20-30 days of age but not before the age of 15 days (preclinical). Since protease nexin-1 (PN-1) is known to be a physiological inhibitor of thrombin, we also examined the expression pattern of PN-1. We found that PN-1 transcription and translation is down-regulated in the muscular tissues of mdx mice, before the onset of clinical symptoms. These results suggest that thrombin may be involved in the progression of muscular dystrophy or the regeneration of muscle fibers after the onset of the disease and that the reduced level of PN-1 may enhance the activities stimulate the activities of muscle proteases, including dystrypsin, at a preclinical stage in mdx mice.
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Affiliation(s)
- Hitoshi Sawada
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, 517-0004 Toba, Japan.
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24
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Muntoni F, Torelli S, Ferlini A. Dystrophin and mutations: one gene, several proteins, multiple phenotypes. Lancet Neurol 2003; 2:731-40. [PMID: 14636778 DOI: 10.1016/s1474-4422(03)00585-4] [Citation(s) in RCA: 723] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A large and complex gene on the X chromosome encodes dystrophin. Many mutations have been described in this gene, most of which affect the expression of the muscle isoform, the best-known protein product of this locus. These mutations result in the Duchenne and Becker muscular dystrophies (DMD and BMD). However, there are several other tissue specific isoforms of dystrophin, some exclusively or predominantly expressed in the brain or the retina. Mutations affecting the correct expression of these tissue-specific isoforms have been associated with the CNS involvement common in DMD. Rare mutations also account for the allelic disorder X-linked dilated cardiomyopathy, in which dystrophin expression or function is affected mostly or exclusively in the heart. Genotype definition of the dystrophin gene in patients with dystrophinopathies has taught us much about functionally important domains of the protein itself and has provided insights into several regulatory mechanisms governing the gene expression profile. Here, we focus on current understanding of the genotype-phenotype relation for mutations in the dystrophin gene and their implications for gene functions.
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Affiliation(s)
- Francesco Muntoni
- Department of Paediatrics, Imperial College London, Hammersmith Hospital Campus, London, UK.
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25
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Sawada H, Nagahiro K, Kikukawa Y, Ban S, Kakefuda R, Shiomi T, Yokosawa H. Therapeutic effect of camostat mesilate on Duchenne muscular dystrophy in mdx mice. Biol Pharm Bull 2003; 26:1025-7. [PMID: 12843632 DOI: 10.1248/bpb.26.1025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Duchenne muscular dystrophy is known to be caused by a defective gene of dystrophin, a 427-kDa cytoskeletal protein, but the effective therapeutic drug is presently unavailable. We previously reported that a trypsin-like protease designated as dystrypsin is markedly activated in the muscle microsomal fraction immediately before onset of the clinical signs in mdx mice, a dystrophin-deficient hereditary animal model for human Duchenne muscular dystrophy. In order to examine the possible participation of dystrypsin in the occurrence of the disease, we investigated the therapeutic effects of dystrypsin inhibitors on the occurrence and progress of muscular dystrophy. Here, we show that camostat mesilate, a low-molecular-weight inhibitor of trypsin-like proteases, including dystrypsin, is a candidate drug for Duchenne muscular dystrophy.
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Affiliation(s)
- Hitoshi Sawada
- Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
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26
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Akusjärvi G, Stévenin J. Remodelling of the host cell RNA splicing machinery during an adenovirus infection. Curr Top Microbiol Immunol 2003; 272:253-86. [PMID: 12747553 DOI: 10.1007/978-3-662-05597-7_9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adenovirus makes extensive use of RNA splicing to produce a complex set of spliced mRNAs during virus replication. All transcription units, except pIX and IVa2, encode multiple alternatively spliced mRNAs. The accumulation of viral mRNAs is subjected to a temporal regulation, a mechanism that ensures that proteins that are needed at certain stages of the viral life cycle are produced. The complex interaction between host cell RNA splicing factors and viral regulatory elements has been studied intensely during the last decade. Such studies have begun to produce a picture of how adenovirus remodels the host cell RNA splicing machinery to orchestrate the shift from the early to the late profile of viral mRNA accumulation. Recent progress has to a large extent focused on the mechanisms regulating E1A and L1 alternative splicing. Here we will review the current knowledge of cis-acting sequence element, trans-acting factors and mechanisms controlling E1A and L1 alternative splicing.
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Affiliation(s)
- G Akusjärvi
- Department of Medical Biochemistry and Microbiology, BMC, Uppsala University, 751 23 Uppsala, Sweden
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27
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Krupnick AS, Zhu J, Nguyen T, Kreisel D, Balsara KR, Lankford EB, Clark CC, Levine S, Stedman HH, Shrager JB. Inspiratory loading does not accelerate dystrophy in mdx mouse diaphragm: implications for regenerative therapy. J Appl Physiol (1985) 2003; 94:411-9. [PMID: 12531909 DOI: 10.1152/japplphysiol.00689.2002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Since the finding that the mdx mouse diaphragm, in contrast to limb muscles, undergoes progressive degeneration analogous to that seen in Duchenne muscular dystrophy, the relationship between the workload on a muscle and the pathogenesis of dystrophy has remained controversial. We increased the work performed by the mdx mouse diaphragm in vivo by tracheal banding and evaluated the progression of dystrophic changes in that muscle. Despite the establishment of dramatically increased respiratory workload and accelerated myofiber damage documented by Evans blue dye, no change in the pace of progression of dystrophy was seen in banded animals vs. unbanded, sham-operated controls. At the completion of the study, more centrally nucleated fibers were evident in the diaphragms of banded mdx mice than in sham-operated mdx controls, indicating that myofiber regeneration increases to meet the demands of the work-induced damage. These data suggest that there is untapped regenerative capacity in dystrophin-deficient muscle and validates experimental efforts aimed at augmenting regeneration within skeletal muscle as a therapeutic strategy in the treatment of dystrophinopathies.
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Affiliation(s)
- Alexander S Krupnick
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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28
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Abstract
The molecular epidemiology of factor IX germline mutations in patients with hemophilia B has been studied in detail because it is an advantageous model for analyzing recent germline mutations in humans. It is estimated that mutations have been defined in the majority of nucleotides that are the target for mutation. The likelihood that a factor IX missense mutation will cause disease correlates with the degree of evolutionary conservation of the amino acid. Mutation rates per base-pair have been estimated after careful consideration and correction for biases, predicting about 76 de novo mutations per generation per individual resulting in 0.3 deleterious changes. The male-to-female sex ratio of mutation varies with the type of mutation. There is evidence for a maternal age effect and an excess of non-CpG G:C to A:T transitions. The factor IX mutation pattern is similar among geographically, racially and ethnically diverse human populations. The data support primarily endogenous mechanisms of germline mutation in the factor IX gene. Mutations at splice junctions are compatible with simple rules for predicting disease causing mutations.
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Affiliation(s)
- S S Sommer
- Department of Molecular Genetics, Beckman Research Institute, 1450 East Duarte Road, City of Hope, Duarte, CA 91010-0269, USA.
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29
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De la Porte S, Morin S, Koenig J. Characteristics of skeletal muscle in mdx mutant mice. INTERNATIONAL REVIEW OF CYTOLOGY 1999; 191:99-148. [PMID: 10343393 DOI: 10.1016/s0074-7696(08)60158-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We review the extensive research conducted on the mdx mouse since 1987, when demonstration of the absence of dystrophin in mdx muscle led to X-chromosome-linked muscular dystrophy (mdx) being considered as a homolog of Duchenne muscular dystrophy. Certain results are contradictory. We consider most aspects of mdx skeletal muscle: (i) the distribution and roles of dystrophin, utrophin, and associated proteins; (ii) morphological characteristics of the skeletal muscle and hypotheses put forward to explain the regeneration characteristic of the mdx mouse; (iii) special features of the diaphragm; (iv) changes in basic fibroblast growth factor, ion flux, innervation, cytoskeleton, adhesive proteins, mastocytes, and metabolism; and (v) different lines of therapeutic research.
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Affiliation(s)
- S De la Porte
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS UPR 9040, Gif sur Yvette, France
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30
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McIntosh TJ. Chapter 2 Structure and Physical Properties of the Lipid Membrane. CURRENT TOPICS IN MEMBRANES 1999. [DOI: 10.1016/s0070-2161(08)61040-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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31
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Sommer SS, Ketterling RP. The factor IX gene as a model for analysis of human germline mutations: an update. Hum Mol Genet 1996; 5 Spec No:1505-14. [PMID: 8875257 DOI: 10.1093/hmg/5.supplement_1.1505] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The variation generated by germline mutation is essential for evolution, but individuals pay a steep price in the form of Mendelian disease and genetic predisposition to complex disease. Indeed, the health of a species is determined ultimately by the rate of germline mutation. Analysis of the factor IX gene in patients with hemophilia B has provided insights into the human germline mutational process. Herein, seven topics will be reviewed with emphasis on recent advances: (i) proposed mechanisms of deletions, inversions, and insertions; (ii) discordant sex ratios of mutation and associated age effects; (iii) somatic mosaicism; (iv) founder effects; (v) mutation rates; (vi) the factor IX gene as a germline mutagen test; and (vii) cancer as a possible mechanism for maintaining a constant rate of germline mutation.
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Affiliation(s)
- S S Sommer
- Department of Biochemistry and Molecular Biology, Mayo Clinic/Foundation, Rochester, MN 55905, USA
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32
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Hirtzlin I. Transfer of DNA tests from research to routine laboratories: some lessons from the French experience in the case of Duchenne muscular dystrophy. Health Policy 1996; 35:1-11. [PMID: 10172594 DOI: 10.1016/0168-8510(95)00773-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the last few years, the activity of research laboratories has led to the emergence of new DNA diagnostic tests in France. They permit the origin of genetic diseases to be identified and provide an answer concerning the detection of carriers and prevention. Nevertheless, given this, new actors have emerged on the health care scene: the research workers who developed the tests and who work in public research laboratories. The economic question of the transfer of the test practice from research to hospital laboratories is the main topic of this paper, taking Duchenne Muscular Dystrophy (DMD) DNA diagnostic tests as the example. After a presentation of the complexity of DNA tests for DMD, the fact that financial and human constraints do not allow the actors to continue to produce the DNA tests is discussed. The financial role of the non-profit-making associations is then explained and leads to the conclusion that a more global policy on DNA tests, such as carried out in the UK and the Netherlands, should be adopted in France by the Social Security if it wants DNA testing activity to be pursued.
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33
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Affiliation(s)
- R G Roberts
- Division of Medical and Molecular Genetics, United Medical and Dental Schools, London, United Kingdom
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34
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Imperiale MJ, Akusjnärvi G, Leppard KN. Post-transcriptional control of adenovirus gene expression. Curr Top Microbiol Immunol 1995; 199 ( Pt 2):139-71. [PMID: 7555066 DOI: 10.1007/978-3-642-79499-5_6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- M J Imperiale
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620, USA
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35
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Nobile C, Marchi J. A refined restriction map of YAC clones spanning the entire human dystrophin gene. Mamm Genome 1994; 5:566-71. [PMID: 8000141 DOI: 10.1007/bf00354931] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The enormous size of the human dystrophin gene (2300 kb) has so far hindered the analysis of its organization and the characterization at the genomic level of the deletion and duplication mutations causing Duchenne or Becker muscular dystrophy. A detailed physical map of the gene locus would considerably simplify these studies. We constructed a refined, long-range restriction map of the entire human dystrophin gene, using 12 overlapping YAC clones as DNA sources. The sites for six rare cutting enzymes (SfiI, NruI, EagI, BssHII, SacII, and NotI) were mapped by partial digest analysis of YACs over a region of 2600 kb, within a level of resolution of about 10 kb. Such a map provides the first detailed representation of the physical structure of the dystrophin gene. It will be useful for mapping unlocalized exons and, eventually, for the characterization of deletions and duplications leading to disease.
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Affiliation(s)
- C Nobile
- Istituto di Genetica Molecolare del CNR, Laboratori di Ricaerca Formazione di Porto Conte, Alghero, Italy
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36
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Garrett KP, Tan S, Bradsher JN, Lane WS, Conaway JW, Conaway RC. Molecular cloning of an essential subunit of RNA polymerase II elongation factor SIII. Proc Natl Acad Sci U S A 1994; 91:5237-41. [PMID: 8202474 PMCID: PMC43969 DOI: 10.1073/pnas.91.12.5237] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A transcription factor designated SIII was recently purified from mammalian cells and shown to regulate the activity of the RNA polymerase II elongation complex. SIII is a heterotrimer composed of approximately 110-, 18-, and 15-kDa polypeptides and is capable of increasing the overall rate of RNA chain elongation by RNA polymerase II by suppressing transient pausing of polymerase at multiple sites on the DNA template. Here we describe the molecular cloning and characterization of a cDNA encoding the functional 15-kDa subunit (p15) of SIII. The p15 cDNA encodes a 112-amino-acid polypeptide with a calculated molecular mass of 12,473 Da and an electrophoretic mobility indistinguishable from that of the natural p15 subunit. When combined with the 110- and 18-kDa SIII subunits, bacterially expressed p15 efficiently replaces the natural p15 subunit in reconstitution of transcriptionally active SIII. A homology search revealed that the amino-terminal half of the SIII p15 subunit shares significant sequence similarity with a portion of the RNA-binding domain of Escherichia coli transcription termination protein rho and with the E. coli NusB protein, suggesting that SIII may be evolutionarily related to proteins involved in the control of transcription elongation in eubacteria.
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Affiliation(s)
- K P Garrett
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City 73104
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37
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Sommer SS, Ketterling RP. How precisely can data from transgenic mouse mutation-detection systems be extrapolated to humans?: lesions from the human factor IX gene. Mutat Res 1994; 307:517-31. [PMID: 7514726 DOI: 10.1016/0027-5107(94)90263-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Transgenic mutation-detection systems have been pioneered in mice, but the approach is applicable to any species in which transgenic animals can be generated. The observed mutations seen in mutation-detection systems are influenced by the underlying pattern of mutation, i.e., the mutational pattern that occurs in wild-type organisms in endogenous segments of DNA that are not under selective pressure. Unfortunately, the biology of most genes and assays markedly skew the underlying pattern of mutation. Herein, we raise multiple issues that must be addressed in order to estimate the underlying pattern of spontaneous mutation from transgenic mouse mutation-detection systems. If these issues can be addressed, the underlying pattern of spontaneous mutation can then be deduced for multiple cell types and for transgenes integrated into different parts of the genome. Even though transgenic methodology cannot be applied directly to humans, it is likely that comparable data on the underlying pattern of spontaneous mutation will be available in humans. Such data are currently available for germline mutations in the factor IX gene. These data are reviewed because of their relevance to two of the multiple issues that must be addressed in transgenic mouse mutation-detection systems: (1) How can the underlying pattern of mutation be deduced from the observed pattern? and (2) How similar are the underlying patterns of mutation in humans and in mice? The analysis of recent germ-line mutation in the factor IX gene yield estimates of the mutation rates per base pair per generation. In brief, the mutation rates vary from 0.037 x 10(-10) for deletions (> 20 bp) to 360 x 10(-10) for transitions at the dinucleotide CpG. If these mutation rates are extrapolated to the entire genome, the aggregate mutation rate is estimated to be 36 x 10(-10). This implies that the diploid genome of each person contains about 21 de novo mutations. In the future, the underlying pattern of spontaneous mutation will be deduced for multiple human genes and these will serve as benchmarks to assess the similarity of the mutational process in humans and in mice.
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Affiliation(s)
- S S Sommer
- Department of Biochemistry and Molecular Biology, Mayo Clinic/Foundation, Rochester, MN 55905
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38
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Schmitz F, Holbach M, Drenckhahn D. Colocalization of retinal dystrophin and actin in postsynaptic dendrites of rod and cone photoreceptor synapses. HISTOCHEMISTRY 1993; 100:473-9. [PMID: 8163390 DOI: 10.1007/bf00267828] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this paper we demonstrate immunostaining specific for dystrophin in photoreceptor synapses of human, bovine and rat retinas. Cryosections of retinas incubated with dystrophin-specific monoclonal antibodies displayed a punctuate staining pattern in the outer plexiform layer. This pattern resulted from binding of the antibodies to synaptic complexes of both rods and cones, shown by double-labelling with antibodies to either synaptophysin or actin. Confocal laser fluorescence microscopy demonstrated that dystrophin staining colocalized predominantly with actin, which is concentrated in the postsynaptic portions of the synaptic complex. No significant dystrophin immunolabel was seen in the presynaptic terminals labelled with antibodies to synaptophysin, a marker of synaptic vesicles. Immunoblot analysis confirmed the presence of approximately 420 kDa and approximately 360 kDa dystrophin-like polypeptide bands associated with membranes of the bovine retina. We speculate that retinal dystrophin is involved in the linkage of actin filaments to the postsynaptic plasma membrane. Such a linkage may be important for the generation of synaptic microdomains and for certain phenomena of synaptic plasticity. The absence of dystrophin in patients suffering from Duchenne's muscular dystrophy is accompanied by visual problems and abnormalities of the electroretinogram. Therefore it is likely that retinal dystrophin plays a role in certain stages of synaptic transmission between photoreceptors and the postsynaptic dendritic complex formed by horizontal and bipolar cells.
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Affiliation(s)
- F Schmitz
- Institute of Anatomy, University of Würzburg, Germany
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39
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Topaloğlu H, Dinçer P, Göğüş S, Ayter S, Topçu M. An unusual case of Duchenne muscular dystrophy. Brain Dev 1993; 15:313-5. [PMID: 8250158 DOI: 10.1016/0387-7604(93)90032-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A 10-year-old boy with Duchenne muscular dystrophy (DMD), with quite unusual clinical data, is presented. He was unable to walk until age 6, walked only for 9 months and then became wheel-chair bound. No dystrophin was present on muscle biopsy sections and a large deletion was found in the dystrophin gene. The deletion encompassed the central high frequency deletion region of the gene. Early developmental milestones may be delayed in DMD, but patients usually start to walk around 2-3 years of age. A delay of the extent in this case is very unusual.
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Affiliation(s)
- H Topaloğlu
- Department of Pediatric Neurology, Hacettepe University, Children's Hospital, Ankara, Turkey
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40
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Cartaud J, Changeux JP. Post-transcriptional compartmentalization of acetylcholine receptor biosynthesis in the subneural domain of muscle and electrocyte junctions. Eur J Neurosci 1993; 5:191-202. [PMID: 8261100 DOI: 10.1111/j.1460-9568.1993.tb00485.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J Cartaud
- Biologie Cellulaire des Membranes, Institut Jacques Monod, CNRS, Université Paris VII, France
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41
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Bettecken T, Aissani B, Müller CR, Bernardi G. Compositional mapping of the human dystrophin-encoding gene. Gene 1992; 122:329-35. [PMID: 1487147 DOI: 10.1016/0378-1119(92)90222-b] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The genomes of warm-blooded vertebrates are mosaics of long DNA segments (> 300 kb, on the average), the isochores, homogeneous in GC levels, which belong to a small number of compositional families. In the present work, the human dystrophin-encoding gene, spanning more than 2.3 Mb in Giemsa band Xp21 (on the short arm of the X chromosome), was analyzed in its isochore organization by hybridizing cDNA probes, corresponding to eight contiguous segments of the coding sequence, on compositional fractions from human DNA. Five DNA regions of uniform (+/- 0.5%) GC content, separated by compositional discontinuities of about 2% GC, were found, so providing the first high-resolution compositional map obtained for a human genome locus and the first direct estimate of isochore size (360 kb to more than 770 kb, in the locus under consideration). One of the isochores contains 71% and another one 21% of deletion breakpoints found in patients suffering from Duchenne's and Becker's muscular dystrophies.
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Affiliation(s)
- T Bettecken
- Institut für Humangenetik, Universität Würzburg, Biozentrum, Germany
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42
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Masuda T, Fujimaki N, Ozawa E, Ishikawa H. Confocal laser microscopy of dystrophin localization in guinea pig skeletal muscle fibers. J Cell Biol 1992; 119:543-8. [PMID: 1400591 PMCID: PMC2289681 DOI: 10.1083/jcb.119.3.543] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A confocal laser microscope was used to analyze the localization pattern of dystrophin along the sarcolemma in guinea pig skeletal muscle fibers. Hind leg muscles of the normal animals were freshly dissected and frozen for cryostat sections, which were then stained with a monoclonal antidystrophin antibody. In confocal laser microscopy, immunofluorescence staining in relatively thick sections could be sharply imaged in thin optical sections. When longitudinal and transverse sections of muscle fibers were examined, the immunostaining of dystrophin was seen as linearly aligned fluorescent dots or intermittent lines along the sarcolemma. In longitudinally cut muscle fibers, many fluorescent dots, but not all, corresponded to the sarcomere pattern, especially the I band. Sections cut tangential to the sarcolemma also showed a lattice-like pattern of longitudinal and transverse striations of fluorescent dots. Double staining for dystrophin and vinculin showed that the two proteins were not exactly colocalized. The end portions of muscle fibers were much more intensely stained with antidystrophin antibody than the central portions, following the contour of elaborate surface specializations at the myo-tendon junction. The staining pattern at the myo-tendon junction was also discontinuous. These confocal microscopic observations suggest that dystrophin may be localized in a nonuniform, discontinuous pattern along the sarcolemma and in some relationship with the underlying myofibrils.
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Affiliation(s)
- T Masuda
- Department of Anatomy, Gunma University School of Medicine, Japan
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43
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Peng HB, Chen Q. Induction of dystrophin localization in cultured Xenopus muscle cells by latex beads. J Cell Sci 1992; 103 ( Pt 2):551-63. [PMID: 1478954 DOI: 10.1242/jcs.103.2.551] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The distribution of dystrophin in Xenopus myotomal muscle cells was examined in conventional and confocal immunofluorescence microscopy. By labeling dissociated single muscle fibers with a monoclonal or a polyclonal antibody against dystrophin, we found that dystrophin is ten times more concentrated at the myotendinous junction (MTJ) than at the extrajunctional sarcolemma. At the MTJ, dystrophin lines the membrane invaginations where myofibrils attach to the membrane. It is colocalized with talin, but is not related to the distribution of acetylcholine receptors (AChRs) which are clustered at the postsynaptic membrane in the vicinity of the MTJ in these fibers. We found that the localization of dystrophin can be induced in cultured Xenopus myotomal muscle cells by treating them with polystyrene latex beads. Dystrophin is discretely localized at the bead-muscle contacts. With electron microscopy, a sarcolemma specialization with all the salient features of the MTJ, including basal lamina-lined membrane invaginations along which myofibrils make attachment. Although these beads also induce clustering of AChRs, the patterns of dystrophin and AChR localization are distinct. The appearance of dystrophin at the bead-contacted sarcolemma is coincident with the development of the membrane invaginations. This, together with its concentration along membrane invaginations at the MTJ in vivo, suggests a role for dystrophin in the formation of this junctional specialization. Since the signal for MTJ development can be presented to cultured muscle cells in a temporally and spatially controlled manner by beads, this system offers a simple model for analyzing the mechanism of this sarcolemma specialization.
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Affiliation(s)
- H B Peng
- Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599
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44
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Cartaud A, Ludosky MA, Tomé FM, Collin H, Stetzkowski-Marden F, Khurana TS, Kunkel LM, Fardeau M, Changeux JP, Cartaud J. Localization of dystrophin and dystrophin-related protein at the electromotor synapse and neuromuscular junction in Torpedo marmorata. Neuroscience 1992; 48:995-1003. [PMID: 1630633 DOI: 10.1016/0306-4522(92)90288-d] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The immunological identification of dystrophin isoforms at the neuromuscular junction and Torpedo marmorata electromotor synapse was attempted using various antibodies. A polyclonal antibody raised against electrophoretically purified dystrophin from T. marmorata electrocyte has been thoroughly investigated. This antibody recognized dystrophin in the electric tissue as well as sarcolemmal and synaptic neuromuscular junction dystrophin in all studies species (T. marmorata, rat, mice and human) at serum dilutions as high as 1:10,000. At variance, no staining of either the sarcolemma or neuromuscular junction was observed in Duchenne muscular dystrophy or mdx mice skeletal muscles. In these muscles, other members of the dystrophin superfamily, in particular the dystrophin-related protein(s) encoded by autosomal genes are present. These data thus demonstrate the specificity of our antibodies for dystrophin. Anti-dystrophin-related protein antibodies [Khurana et al. (1991) Neuromusc. Disorders 1, 185-194] which gave a strong immunostaining of the neuromuscular junction in various species, including T. marmorata, cross-reacted weakly with the postsynaptic membrane of the electrocyte. Taken together, these observations are in favor of the existence of a protein very homologous to dystrophin at the electromotor synapse in T. marmorata, whereas both dystrophin and dystrophin-related protein co-localize at the neuromuscular junction as in all species studied. The electrocyte thus offers the unique opportunity to study the interaction of dystrophin with components of the postsynaptic membrane.
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Affiliation(s)
- A Cartaud
- Biologie Cellulaire des Membranes, Institut Jacques Monod du CNRS, Université Paris VII, France
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45
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Way M, Pope B, Cross RA, Kendrick-Jones J, Weeds AG. Expression of the N-terminal domain of dystrophin in E. coli and demonstration of binding to F-actin. FEBS Lett 1992; 301:243-5. [PMID: 1577159 DOI: 10.1016/0014-5793(92)80249-g] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The N-terminal head domain of human dystrophin has been expressed in soluble form and high yield in E. coli, allowing us to test the previously unconfirmed assumption that dystrophin binds actin. DMD246, the first 246 amino acid residues of dystrophin, binds F-actin in a strongly co-operative manner with a Hill constant of 3.5, but does not bind G-actin. Dystrophin heads are thus functionally competent actin-binding proteins. This result opens the way to identifying critical residues in the actin-binding site and encourages us that the other domains of dystrophin might also be treated as functionally autonomous modules, accessible to a similar approach.
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Affiliation(s)
- M Way
- MRC Laboratory of Molecular Biology, Cambridge, UK
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46
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Association of the Mr 58,000 postsynaptic protein of electric tissue with Torpedo dystrophin and the Mr 87,000 postsynaptic protein. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42683-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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47
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Gold R, Kress W, Meurers B, Meng G, Reichmann H, Müller CR. Becker muscular dystrophy: detection of unusual disease courses by combined approach to dystrophin analysis. Muscle Nerve 1992; 15:214-8. [PMID: 1549142 DOI: 10.1002/mus.880150214] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The rapid progress of research on the structure of the dystrophin gene has enormously increased our understanding of the molecular basis of Duchenne (DMD) and Becker (BMD) muscular dystrophy. Apart from "classical" clinical presentations, asymptomatic or only mildly affected individuals with deletions in the dystrophin gene have now been reported. We describe two families which were initially classified as metabolic myopathies, until the diagnosis of atypical BMD was established after dystrophin analysis at the protein and DNA level. A modern diagnostic approach to myopathies should, therefore, not only include morphological and biochemical investigations, but also be extended to the analysis of the dystrophin gene.
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Affiliation(s)
- R Gold
- Department of Neurology, University of Würzburg, Planegg-Martinsried, Germany
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48
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Sakuraba H, Ishii K, Shimmoto M, Yamada H, Suzuki Y. A screening for dystrophin gene deletions in Japanese patients with Duchenne/Becker muscular dystrophy by the multiplex polymerase chain reaction. Brain Dev 1991; 13:339-42. [PMID: 1785656 DOI: 10.1016/s0387-7604(12)80129-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A new screening method involving the multiplex polymerase chain reaction was developed to detect dystrophin gene deletions in Japanese patients with Duchenne and Becker muscular dystrophy (DMD/BMD). Eleven exonic regions including deletion "hot spots" were analyzed. Gene deletions were found in 33% of 92 unrelated Japanese patients, mainly in the central portion (exons 43-52) and at the 5' end (exons 1-17). This is a useful laboratory test for the rapid genetic diagnosis of DMD/BMD.
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Affiliation(s)
- H Sakuraba
- Department of Clinical Genetics, Tokyo Metropolitan Institute of Medical Science, Japan
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49
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Stedman HH, Sweeney HL, Shrager JB, Maguire HC, Panettieri RA, Petrof B, Narusawa M, Leferovich JM, Sladky JT, Kelly AM. The mdx mouse diaphragm reproduces the degenerative changes of Duchenne muscular dystrophy. Nature 1991; 352:536-9. [PMID: 1865908 DOI: 10.1038/352536a0] [Citation(s) in RCA: 706] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Although murine X-linked muscular dystrophy (mdx) and Duchenne muscular dystrophy (DMD) are genetically homologous and both characterized by a complete absence of dystrophin, the limb muscles of adult mdx mice suffer neither the detectable weakness nor the progressive degeneration that are features of DMD. Here we show that the mdx mouse diaphragm exhibits a pattern of degeneration, fibrosis and severe functional deficit comparable to that of DMD limb muscle, although adult mice show no overt respiratory impairment. Progressive functional changes include reductions in strength (to 13.5% of control by two years of age), elasticity, twitch speed and fibre length. The collagen density rises to at least seven times that of control diaphragm and ten times that of mdx hind-limb muscle. By 1.5 years of age, similar but less severe histological changes emerge in the accessory muscles of respiration. On the basis of these findings, we propose that dystrophin deficiency alters the threshold for work-induced injury. Our data provide a quantitative framework for studying the pathogenesis of dystrophy and extend the application of the mdx mouse as an animal model.
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Affiliation(s)
- H H Stedman
- School of Medicine, University of Pennsylvania, Philadelphia 19104
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50
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Abstract
In this brief review, we describe the clinical manifestations of Duchenne's muscular dystrophy (DMD) and other similar syndromes, outline the history of the dystrophin gene's identification and its relationship to these muscular dystrophies, and relate the importance of the gene's discovery to clinical neurology. We do not discuss treatment.
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Affiliation(s)
- B K Evans
- Department of Neurology, University of Alabama, Birmingham Medical School 35294
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