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Hoh JFY. Developmental, Physiological and Phylogenetic Perspectives on the Expression and Regulation of Myosin Heavy Chains in Craniofacial Muscles. Int J Mol Sci 2024; 25:4546. [PMID: 38674131 PMCID: PMC11050549 DOI: 10.3390/ijms25084546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/15/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
This review deals with the developmental origins of extraocular, jaw and laryngeal muscles, the expression, regulation and functional significance of sarcomeric myosin heavy chains (MyHCs) that they express and changes in MyHC expression during phylogeny. Myogenic progenitors from the mesoderm in the prechordal plate and branchial arches specify craniofacial muscle allotypes with different repertoires for MyHC expression. To cope with very complex eye movements, extraocular muscles (EOMs) express 11 MyHCs, ranging from the superfast extraocular MyHC to the slowest, non-muscle MyHC IIB (nmMyH IIB). They have distinct global and orbital layers, singly- and multiply-innervated fibres, longitudinal MyHC variations, and palisade endings that mediate axon reflexes. Jaw-closing muscles express the high-force masticatory MyHC and cardiac or limb MyHCs depending on the appropriateness for the acquisition and mastication of food. Laryngeal muscles express extraocular and limb muscle MyHCs but shift toward expressing slower MyHCs in large animals. During postnatal development, MyHC expression of craniofacial muscles is subject to neural and hormonal modulation. The primary and secondary myotubes of developing EOMs are postulated to induce, via different retrogradely transported neurotrophins, the rich diversity of neural impulse patterns that regulate the specific MyHCs that they express. Thyroid hormone shifts MyHC 2A toward 2B in jaw muscles, laryngeal muscles and possibly extraocular muscles. This review highlights the fact that the pattern of myosin expression in mammalian craniofacial muscles is principally influenced by the complex interplay of cell lineages, neural impulse patterns, thyroid and other hormones, functional demands and body mass. In these respects, craniofacial muscles are similar to limb muscles, but they differ radically in the types of cell lineage and the nature of their functional demands.
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Affiliation(s)
- Joseph Foon Yoong Hoh
- Discipline of Physiology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
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Jansen M, de Brouwer R, Hassanzada F, Schoemaker AE, Schmidt AF, Kooijman-Reumerman MD, Bracun V, Slieker MG, Dooijes D, Vermeer AMC, Wilde AAM, Amin AS, Lekanne Deprez RH, Herkert JC, Christiaans I, de Boer RA, Jongbloed JDH, van Tintelen JP, Asselbergs FW, Baas AF. Penetrance and Prognosis of MYH7 Variant-Associated Cardiomyopathies: Results From a Dutch Multicenter Cohort Study. JACC. HEART FAILURE 2024; 12:134-147. [PMID: 37565978 DOI: 10.1016/j.jchf.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 07/07/2023] [Accepted: 07/11/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND MYH7 variants cause hypertrophic cardiomyopathy (HCM), noncompaction cardiomyopathy (NCCM), and dilated cardiomyopathy (DCM). Screening of relatives of patients with genetic cardiomyopathy is recommended from 10 to 12 years of age onward, irrespective of the affected gene. OBJECTIVES This study sought to study the penetrance and prognosis of MYH7 variant-associated cardiomyopathies. METHODS In this multicenter cohort study, penetrance and major cardiomyopathy-related events (MCEs) were assessed in carriers of (likely) pathogenic MYH7 variants by using Kaplan-Meier curves and log-rank tests. Prognostic factors were evaluated using Cox regression with time-dependent coefficients. RESULTS In total, 581 subjects (30.1% index patients, 48.4% male, median age 37.0 years [IQR: 19.5-50.2 years]) were included. HCM was diagnosed in 226 subjects, NCCM in 70, and DCM in 55. Early penetrance and MCEs (age <12 years) were common among NCCM-associated variant carriers (21.2% and 12.0%, respectively) and DCM-associated variant carriers (15.3% and 10.0%, respectively), compared with HCM-associated variant carriers (2.9% and 2.1%, respectively). Penetrance was significantly increased in carriers of converter region variants (adjusted HR: 1.87; 95% CI: 1.15-3.04; P = 0.012) and at age ≤1 year in NCCM-associated or DCM-associated variant carriers (adjusted HR: 21.17; 95% CI: 4.81-93.20; P < 0.001) and subjects with a family history of early MCEs (adjusted HR: 2.45; 95% CI: 1.09-5.50; P = 0.030). The risk of MCE was increased in subjects with a family history of early MCEs (adjusted HR: 1.82; 95% CI: 1.15-2.87; P = 0.010) and at age ≤5 years in NCCM-associated or DCM-associated variant carriers (adjusted HR: 38.82; 95% CI: 5.16-291.88; P < 0.001). CONCLUSIONS MYH7 variants can cause cardiomyopathies and MCEs at a young age. Screening at younger ages may be warranted, particularly in carriers of NCCM- or DCM-associated variants and/or with a family history of MCEs at <12 years.
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Affiliation(s)
- Mark Jansen
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; Department of Cardiology, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; Netherlands Heart Institute, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart).
| | - Remco de Brouwer
- Netherlands Heart Institute, Utrecht, the Netherlands; Department of Cardiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Fahima Hassanzada
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
| | - Angela E Schoemaker
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
| | - Amand F Schmidt
- Department of Cardiology, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, United Kingdom; Department of Cardiology, University Medical Centre Amsterdam, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, University Medical Centre Amsterdam, Amsterdam, the Netherlands
| | - Maria D Kooijman-Reumerman
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
| | - Valentina Bracun
- Department of Cardiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Martijn G Slieker
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Pediatric Cardiology, University Medical Centre Utrecht, Utrecht University, the Netherlands
| | - Dennis Dooijes
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
| | - Alexa M C Vermeer
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Human Genetics, University Medical Centre Amsterdam Amsterdam, University of Amsterdam, Amsterdam, the Netherlands
| | - Arthur A M Wilde
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Cardiology, University Medical Centre Amsterdam, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, University Medical Centre Amsterdam, Amsterdam, the Netherlands
| | - Ahmad S Amin
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Cardiology, University Medical Centre Amsterdam, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, University Medical Centre Amsterdam, Amsterdam, the Netherlands
| | - Ronald H Lekanne Deprez
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Human Genetics, University Medical Centre Amsterdam Amsterdam, University of Amsterdam, Amsterdam, the Netherlands
| | - Johanna C Herkert
- Department of Genetics, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Imke Christiaans
- Department of Genetics, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Rudolf A de Boer
- European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Department of Cardiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands; Department of Cardiology, Thorax Center, Erasmus University Medical Center, Erasmus University Rotterdam, Rotterdam, the Netherlands
| | - Jan D H Jongbloed
- Department of Genetics, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - J Peter van Tintelen
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; Netherlands Heart Institute, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
| | - Folkert W Asselbergs
- Department of Cardiology, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart); Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, United Kingdom; Department of Cardiology, University Medical Centre Amsterdam, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, University Medical Centre Amsterdam, Amsterdam, the Netherlands; Health Data Research UK and Institute of Health Informatics, University College London, London, United Kingdom
| | - Annette F Baas
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands; European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart (ERN GUARD-Heart)
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Smerdu V. Expression of MyHC-15 and -2x in human muscle spindles: An immunohistochemical study. J Anat 2023; 243:826-841. [PMID: 37420120 PMCID: PMC10557391 DOI: 10.1111/joa.13923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
To build on the existing data on the pattern of myosin heavy chain (MyHC) isoforms expression in the human muscle spindles, we aimed to verify whether the 'novel' MyHC-15, -2x and -2b isoforms are co-expressed with the other known isoforms in the human intrafusal fibres. Using a set of antibodies, we attempted to demonstrate nine isoforms (15, slow-tonic, 1, α, 2a, 2x, 2b, embryonic, neonatal) in different regions of intrafusal fibres in the biceps brachii and flexor digitorum profundus muscles. The reactivity of some antibodies with the extrafusal fibres was also tested in the masseter and laryngeal cricothyreoid muscles. In both upper limb muscles, the expression of slow-tonic isoform was a reliable marker for differentiating positive bag fibres from negative chain fibres. Generally, bag1 and bag2 fibres were distinguished in isoform 1 expression; the latter consistently expressed this isoform over their entire length. Although isoform 15 was not abundantly expressed in intrafusal fibres, its expression was pronounced in the extracapsular region of bag fibres. Using a 2x isoform-specific antibody, this isoform was demonstrated in the intracapsular regions of some intrafusal fibres, particularly chain fibres. To the best of our knowledge, this study is the first to demonstrate 15 and 2x isoforms in human intrafusal fibres. However, whether the labelling with an antibody specific for rat 2b isoform reflects the expression of this isoform in bag fibres and some extrafusal ones in the specialised cranial muscles requires further evaluation. The revealed pattern of isoform co-expression only partially agrees with the results of previous, more extensive studies. Nevertheless, it may be inferred that MyHC isoform expression in intrafusal fibres varies along their length, across different muscle spindles and muscles. Furthermore, the estimation of expression may also depend on the antibodies utilised, which may also react differently with intrafusal and extrafusal fibres.
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Affiliation(s)
- Vika Smerdu
- Institute of Anatomy, Faculty of MedicineUniversity of LjubljanaLjubljanaSlovenia
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Hoh JFY. Developmental, physiologic and phylogenetic perspectives on the expression and regulation of myosin heavy chains in mammalian skeletal muscles. J Comp Physiol B 2023:10.1007/s00360-023-01499-0. [PMID: 37277594 DOI: 10.1007/s00360-023-01499-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/05/2023] [Accepted: 05/12/2023] [Indexed: 06/07/2023]
Abstract
The kinetics of myosin controls the speed and power of muscle contraction. Mammalian skeletal muscles express twelve kinetically different myosin heavy chain (MyHC) genes which provides a wide range of muscle speeds to meet different functional demands. Myogenic progenitors from diverse craniofacial and somitic mesoderm specify muscle allotypes with different repertoires for MyHC expression. This review provides a brief synopsis on the historical and current views on how cell lineage, neural impulse patterns, and thyroid hormone influence MyHC gene expression in muscles of the limb allotype during development and in adult life and the molecular mechanisms thereof. During somitic myogenesis, embryonic and foetal myoblast lineages form slow and fast primary and secondary myotube ontotypes which respond differently to postnatal neural and thyroidal influences to generate fully differentiated fibre phenotypes. Fibres of a given phenotype may arise from myotubes of different ontotypes which retain their capacity to respond differently to neural and thyroidal influences during postnatal life. This gives muscles physiological plasticity to adapt to fluctuations in thyroid hormone levels and patterns of use. The kinetics of MyHC isoforms vary inversely with animal body mass. Fast 2b fibres are specifically absent in muscles involved in elastic energy saving in hopping marsupials and generally absent in large eutherian mammals. Changes in MyHC expression are viewed in the context of the physiology of the whole animal. The roles of myoblast lineage and thyroid hormone in regulating MyHC gene expression are phylogenetically the most ancient while that of neural impulse patterns the most recent.
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Affiliation(s)
- Joseph Foon Yoong Hoh
- Discipline of Physiology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.
- , PO Box 152, Killara, NSW, 2071, Australia.
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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Lee LA, Karabina A, Broadwell LJ, Leinwand LA. The ancient sarcomeric myosins found in specialized muscles. Skelet Muscle 2019; 9:7. [PMID: 30836986 PMCID: PMC6402096 DOI: 10.1186/s13395-019-0192-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/22/2019] [Indexed: 12/17/2022] Open
Abstract
Striated muscles express an array of sarcomeric myosin motors that are tuned to accomplish specific tasks. Each myosin isoform found in muscle fibers confers unique contractile properties to the fiber in order to meet the demands of the muscle. The sarcomeric myosin heavy chain (MYH) genes expressed in the major cardiac and skeletal muscles have been studied for decades. However, three ancient myosins, MYH7b, MYH15, and MYH16, remained uncharacterized due to their unique expression patterns in common mammalian model organisms and due to their relatively recent discovery in these genomes. This article reviews the literature surrounding these three ancient sarcomeric myosins and the specialized muscles in which they are expressed. Further study of these ancient myosins and how they contribute to the functions of the specialized muscles may provide novel insight into the history of striated muscle evolution.
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Affiliation(s)
- Lindsey A. Lee
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Anastasia Karabina
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
| | - Lindsey J. Broadwell
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
- Department of Biochemistry, University of Colorado, Boulder, CO USA
| | - Leslie A. Leinwand
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO USA
- BioFrontiers Institute, University of Colorado, Boulder, CO USA
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The genetic basis of hypertrophic cardiomyopathy in cats and humans. J Vet Cardiol 2016; 17 Suppl 1:S53-73. [PMID: 26776594 DOI: 10.1016/j.jvc.2015.03.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 01/16/2015] [Accepted: 03/16/2015] [Indexed: 12/19/2022]
Abstract
Mutations in genes that encode for muscle sarcomeric proteins have been identified in humans and two breeds of domestic cats with hypertrophic cardiomyopathy (HCM). This article reviews the history, genetics, and pathogenesis of HCM in the two species in order to give veterinarians a perspective on the genetics of HCM. Hypertrophic cardiomyopathy in people is a genetic disease that has been called a disease of the sarcomere because the preponderance of mutations identified that cause HCM are in genes that encode for sarcomeric proteins (Maron and Maron, 2013). Sarcomeres are the basic contractile units of muscle and thus sarcomeric proteins are responsible for the strength, speed, and extent of muscle contraction. In people with HCM, the two most common genes affected by HCM mutations are the myosin heavy chain gene (MYH7), the gene that encodes for the motor protein β-myosin heavy chain (the sarcomeric protein that splits ATP to generate force), and the cardiac myosin binding protein-C gene (MYBPC3), a gene that encodes for the closely related structural and regulatory protein, cardiac myosin binding protein-C (cMyBP-C). To date, the two mutations linked to HCM in domestic cats (one each in Maine Coon and Ragdoll breeds) also occur in MYBPC3 (Meurs et al., 2005, 2007). This is a review of the genetics of HCM in both humans and domestic cats that focuses on the aspects of human genetics that are germane to veterinarians and on all aspects of feline HCM genetics.
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Marques MDA, de Oliveira GAP. Cardiac Troponin and Tropomyosin: Structural and Cellular Perspectives to Unveil the Hypertrophic Cardiomyopathy Phenotype. Front Physiol 2016; 7:429. [PMID: 27721798 PMCID: PMC5033975 DOI: 10.3389/fphys.2016.00429] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/09/2016] [Indexed: 12/12/2022] Open
Abstract
Inherited myopathies affect both skeletal and cardiac muscle and are commonly associated with genetic dysfunctions, leading to the production of anomalous proteins. In cardiomyopathies, mutations frequently occur in sarcomeric genes, but the cause-effect scenario between genetic alterations and pathological processes remains elusive. Hypertrophic cardiomyopathy (HCM) was the first cardiac disease associated with a genetic background. Since the discovery of the first mutation in the β-myosin heavy chain, more than 1400 new mutations in 11 sarcomeric genes have been reported, awarding HCM the title of the “disease of the sarcomere.” The most common macroscopic phenotypes are left ventricle and interventricular septal thickening, but because the clinical profile of this disease is quite heterogeneous, these phenotypes are not suitable for an accurate diagnosis. The development of genomic approaches for clinical investigation allows for diagnostic progress and understanding at the molecular level. Meanwhile, the lack of accurate in vivo models to better comprehend the cellular events triggered by this pathology has become a challenge. Notwithstanding, the imbalance of Ca2+ concentrations, altered signaling pathways, induction of apoptotic factors, and heart remodeling leading to abnormal anatomy have already been reported. Of note, a misbalance of signaling biomolecules, such as kinases and tumor suppressors (e.g., Akt and p53), seems to participate in apoptotic and fibrotic events. In HCM, structural and cellular information about defective sarcomeric proteins and their altered interactome is emerging but still represents a bottleneck for developing new concepts in basic research and for future therapeutic interventions. This review focuses on the structural and cellular alterations triggered by HCM-causing mutations in troponin and tropomyosin proteins and how structural biology can aid in the discovery of new platforms for therapeutics. We highlight the importance of a better understanding of allosteric communications within these thin-filament proteins to decipher the HCM pathological state.
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Affiliation(s)
- Mayra de A Marques
- Programa de Biologia Estrutural, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Guilherme A P de Oliveira
- Programa de Biologia Estrutural, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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Bhuiyan SS, Kinoshita S, Wongwarangkana C, Asaduzzaman M, Asakawa S, Watabe S. Evolution of the myosin heavy chain gene MYH14 and its intronic microRNA miR-499: muscle-specific miR-499 expression persists in the absence of the ancestral host gene. BMC Evol Biol 2013; 13:142. [PMID: 24059862 PMCID: PMC3716903 DOI: 10.1186/1471-2148-13-142] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 06/13/2013] [Indexed: 12/17/2022] Open
Abstract
Background A novel sarcomeric myosin heavy chain gene, MYH14, was identified following the completion of the human genome project. MYH14 contains an intronic microRNA, miR-499, which is expressed in a slow/cardiac muscle specific manner along with its host gene; it plays a key role in muscle fiber-type specification in mammals. Interestingly, teleost fish genomes contain multiple MYH14 and miR-499 paralogs. However, the evolutionary history of MYH14 and miR-499 has not been studied in detail. In the present study, we identified MYH14/miR-499 loci on various teleost fish genomes and examined their evolutionary history by sequence and expression analyses. Results Synteny and phylogenetic analyses depict the evolutionary history of MYH14/miR-499 loci where teleost specific duplication and several subsequent rounds of species-specific gene loss events took place. Interestingly, miR-499 was not located in the MYH14 introns of certain teleost fish. An MYH14 paralog, lacking miR-499, exhibited an accelerated rate of evolution compared with those containing miR-499, suggesting a putative functional relationship between MYH14 and miR-499. In medaka, Oryzias latipes, miR-499 is present where MYH14 is completely absent in the genome. Furthermore, by using in situ hybridization and small RNA sequencing, miR-499 was expressed in the notochord at the medaka embryonic stage and slow/cardiac muscle at the larval and adult stages. Comparing the flanking sequences of MYH14/miR-499 loci between torafugu Takifugu rubripes, zebrafish Danio rerio, and medaka revealed some highly conserved regions, suggesting that cis-regulatory elements have been functionally conserved in medaka miR-499 despite the loss of its host gene. Conclusions This study reveals the evolutionary history of the MYH14/miRNA-499 locus in teleost fish, indicating divergent distribution and expression of MYH14 and miR-499 genes in different teleost fish lineages. We also found that medaka miR-499 was even expressed in the absence of its host gene. To our knowledge, this is the first report that shows the conversion of intronic into non-intronic miRNA during the evolution of a teleost fish lineage.
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Affiliation(s)
- Sharmin Siddique Bhuiyan
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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Myers JM, Fairweather D, Huber SA, Cunningham MW. Autoimmune myocarditis, valvulitis, and cardiomyopathy. CURRENT PROTOCOLS IN IMMUNOLOGY 2013; Chapter 15:Unit 15.14.1-51. [PMID: 23564686 PMCID: PMC3672855 DOI: 10.1002/0471142735.im1514s101] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myocarditis and valvulitis are inflammatory diseases affecting myocardium and valve. Myocarditis, a viral-induced disease of myocardium, may lead to dilated cardiomyopathy and loss of heart function. Valvulitis leads to deformed heart valves and altered blood flow in rheumatic heart disease. Animal models recapitulating these diseases are important in understanding the human condition. Cardiac myosin is a major autoantigen in heart, and antibodies and T cells to cardiac myosin are evident in inflammatory heart diseases. This unit is a practical guide to induction and evaluation of experimental autoimmune myocarditis (EAM) in several mouse strains and the Lewis rat. Purification protocols for cardiac myosin and protocols for induction of EAM by cardiac myosin and its myocarditis-producing peptides, and coxsackievirus CVB3, are defined. Protocols for assessment of myocarditis and valvulitis in humans and animal models provide methods to define functional autoantibodies targeting cardiac myosin, β-adrenergic, and muscarinic receptors, and their deposition in tissues.
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Affiliation(s)
- Jennifer M Myers
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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Abstract
This review provides an historical and personal perspective on the discovery of genetic causes for hypertrophic cardiomyopathy (HCM). Extraordinary insights by physicians who initially detailed remarkable and varied manifestations of the disorder, collaboration among multidisciplinary teams with skills in clinical diagnostics and molecular genetics, and hard work by scores of trainees solved the etiologic riddle of HCM and unexpectedly demonstrated mutations in sarcomere protein genes as the cause of disease. In addition to celebrating 20 years of genetic research in HCM, this article serves as an introductory overview to a thematic review series that will present contemporary advances in the field of hypertrophic heart disease. Through the continued application of advances in genetic methodologies, combined with biochemical and biophysical analyses of the consequences of human mutations, fundamental knowledge about HCM and sarcomere biology has emerged. Expanding research to elucidate the mechanisms by which subtle genetic variation in contractile proteins remodel the human heart remains an exciting opportunity, one with considerable promise to provide new strategies to limit or even prevent HCM pathogenesis.
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Affiliation(s)
- Christine E Seidman
- Cardiovascular Division, Department of Genetics, Brigham & Women's Hospital, Boston, MA 02115, USA.
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Reiser PJ, Bicer S, Patel R, An Y, Chen Q, Quan N. The myosin light chain 1 isoform associated with masticatory myosin heavy chain in mammals and reptiles is embryonic/atrial MLC1. ACTA ACUST UNITED AC 2010; 213:1633-42. [PMID: 20435813 DOI: 10.1242/jeb.039453] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We recently reported that masticatory myosin heavy chain (MHC-M) is expressed as the exclusive or predominant MHC isoform in masseter and temporalis muscles of several rodent species, contrary to the prevailing dogma that rodents express almost exclusively MHC isoforms that are typically found in fast limb muscles and not masticatory myosin. We also reported that the same rodent species express the embryonic/atrial isoform of myosin light chain 1 (MLC1E/A) in jaw-closing muscles and not a unique masticatory MLC1 isoform that others have reported as being expressed in jaw-closing muscles of carnivores that express MHC-M. The objective of this study was to test the hypothesis that MLC1E/A is consistently expressed in jaw-closing muscles whenever MHC-M is expressed as the predominant or exclusive MHC isoform. Jaw-closing muscles, fast and slow limb muscles, and cardiac atria and ventricles of 19 species (six Carnivora species, one Primates species, one Chiroptera species, five marsupial species, an alligator and five turtle species) were analyzed using protein gel electrophoresis, immunoblotting, mass spectrometry and RNA sequencing. Gel electrophoresis and immunoblotting indicate that MHC-M is the exclusive or predominant MHC isoform in the jaw-closing muscles of each of the studied species. The results from all of the approaches collectively show that MLC1E/A is exclusively or predominantly expressed in jaw-closing muscles of the same species. We conclude that MLC1E/A is the exclusive or predominant MLC1 isoform that is expressed in jaw-closing muscles of vertebrates that express MHC-M, and that a unique masticatory isoform of MLC1 probably does not exist.
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Affiliation(s)
- Peter J Reiser
- Department of Oral Biology, The Ohio State University, Postle Hall, Box 192, 305 West 12th Avenue, Columbus, OH 43210, USA.
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13
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Herron TJ, Devaney EJ, Metzger JM. Modulation of cardiac performance by motor protein gene transfer. Ann N Y Acad Sci 2008; 1123:96-104. [PMID: 18375581 DOI: 10.1196/annals.1420.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cardiac muscle performance can be determined by factors intrinsic to each cardiac muscle cell, such as protein isoform expression. One protein whose expression plays a major role in determining cardiac performance is myosin. Myosin is the heart's molecular motor which transduces the chemical energy from ATP hydrolysis into the mechanical energy of each heartbeat. Alterations of myosin isoform expression are routinely associated with acquired and inherited cases of cardiomyopathy. For example, human heart failure is consistently associated with increased expression of a slow myosin motor isoform and a concomitant decreased expression of the heart's fast myosin motor isoform. Further, mutations of the cardiac myosin gene are the most common cause of inherited hypertrophic cardiomyopathy. Transgenic animal studies have provided insight into cardiac functional effects caused by myosin isoform gene switching (fast-to-slow myosin or slow-to-fast myosin) or by expression of a disease-related mutant motor. More direct structure-function analysis using acute gene transfer of myosin motors provides evidence that the inotropic state of cardiac muscle can be affected by motor protein isoform shifting independent of intracellular calcium handling. Because most therapies for the diseased heart target intracellular calcium handling, acute gene transfer of cardiac molecular motors to modulate heart performance offers a novel therapeutic strategy for the compromised heart. Although the development of safe vectors for therapeutic myosin gene delivery are in their infancy, studies focused on acute genetic engineering of the heart's molecular motor will provide a foundation for therapeutic vector development and insight into mechanisms that contribute to cardiomyopathy.
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Affiliation(s)
- Todd J Herron
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
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14
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Thick and thin filament gene mutations in striated muscle diseases. Int J Mol Sci 2008; 9:1259-1275. [PMID: 19325803 PMCID: PMC2635722 DOI: 10.3390/ijms9071259] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 05/23/2008] [Accepted: 06/12/2008] [Indexed: 01/05/2023] Open
Abstract
The sarcomere is the fundamental unit of cardiac and skeletal muscle contraction. During the last ten years, there has been growing awareness of the etiology of skeletal and cardiac muscle diseases originating in the sarcomere, an important evolving field. Many sarcomeric diseases affect newborn children, i. e. are congenital myopathies. The discovery and characterization of several myopathies caused by mutations in myosin heavy chain genes, coding for the major component of skeletal muscle thick filaments, has led to the introduction of a new entity in the field of neuromuscular disorders: myosin myopathies. Recently, mutations in genes coding for skeletal muscle thin filaments, associated with various clinical features, have been identified. These mutations evoke distinct structural changes within the sarcomeric thin filament. Current knowledge regarding contractile protein dysfunction as it relates to disease pathogenesis has failed to decipher the mechanistic links between mutations identified in sarcomeric proteins and skeletal myopathies, which will no doubt require an integrated physiological approach. The discovery of additional genes associated with myopathies and the elucidation of the molecular mechanisms of pathogenesis will lead to improved and more accurate diagnosis, including prenatally, and to enhanced potential for prognosis, genetic counseling and developing possible treatments for these diseases. The goal of this review is to present recent progress in the identification of gene mutations from each of the major structural components of the sarcomere, the thick and thin filaments, related to skeletal muscle disease. The genetics and clinical manifestations of these disorders will be discussed.
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15
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Danzi S, Klein S, Klein I. Differential regulation of the myosin heavy chain genes alpha and beta in rat atria and ventricles: role of antisense RNA. Thyroid 2008; 18:761-8. [PMID: 18631005 PMCID: PMC2879492 DOI: 10.1089/thy.2008.0043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND The myosin heavy chain (MHC) genes are regulated by triiodothyronine (T3) in a reciprocal and chamber-specific manner. To further our understanding of the potential mechanisms involved, we determined the T3 responsiveness of the MHC genes, alpha and beta, and the beta-MHC antisense (AS) gene in the rat ventricles and atria. METHODS Hypothyroid rats were administered a single physiologic (1 microg) or pharmacologic (20 microg) dose of T3, and sequential measurements of beta-MHC hn- and AS RNA and alpha-MHC heterogeneous nuclear RNA from rat ventricular and atrial myocardium were performed with reverse transcription PCR. RESULTS We have demonstrated that T3 treatment increases the myocyte content of an AS beta-MHC RNA in atria and ventricles that includes sequences complementary to both the first 5' and last 3' introns of the beta-MHC sense transcript. In the hypothyroid rat ventricle, beta-MHC sense RNA expression is maximal, while in the euthyroid rat ventricle, beta-MHC AS RNA is maximal. beta-MHC AS expression increased by 52 +/- 9.8% at the peak, 24 hours after injection of a physiologic dose of T3 (1 microg/animal), while beta-MHC sense RNA decreased by 41 +/- 2.2% at 36 hours, the nadir. In hypothyroid atria, beta-MHC AS RNA was induced by threefold within 6 hours of administration of 1 microg T3, demonstrating that in the atria, beta-MHC AS expression is regulated by T3, while alpha-MHC expression is not. CONCLUSIONS In the hypothyroid rat heart ventricle, beta-MHC AS RNA expression increases in response to T3 similar to that of alpha-MHC. Simultaneous measures of beta-MHC sense RNA are decreased, suggesting a possible mechanism for AS to regulate sense expression. In atria, while alpha-MHC is not influenced by thyroid state, beta-MHC sense and AS RNA were simultaneously and inversely altered in response to T3. This confirms a close positive relationship between T3 and beta-MHC AS RNA in both the atria and ventricles, while demonstrating for the first time that alpha- and beta-MHC expression is not coupled in the atria.
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Affiliation(s)
- Sara Danzi
- Feinstein Institute for Medical Research and the Department of Medicine, North Shore University Hospital, Manhasset, New York
- Department of Medicine, NYU School of Medicine, Manhasset, New York
| | - Steven Klein
- Feinstein Institute for Medical Research and the Department of Medicine, North Shore University Hospital, Manhasset, New York
| | - Irwin Klein
- Feinstein Institute for Medical Research and the Department of Medicine, North Shore University Hospital, Manhasset, New York
- Department of Medicine, NYU School of Medicine, Manhasset, New York
- Department of Cell Biology, NYU School of Medicine, Manhasset, New York
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16
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Rinaldi C, Haddad F, Bodell PW, Qin AX, Jiang W, Baldwin KM. Intergenic bidirectional promoter and cooperative regulation of the IIx and IIb MHC genes in fast skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2008; 295:R208-18. [PMID: 18434443 DOI: 10.1152/ajpregu.00134.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated the dynamic regulation of IIx-IIb MHC genes in the fast white medial gastrocnemius (WMG) muscle in response to intermittent resistance exercise training (RE), a model associated with a rapid shift from IIb to IIx expression (11). We investigated the effect of 4 days of RE on the transcriptional activity across the skeletal MHC gene locus in the WMG in female Sprague-Dawley rats. Our results show that RE resulted in significant shifts from IIb to IIx observed at both the pre-mRNA and mRNA levels. An antisense RNA (xII NAT) was detected in the intergenic (IG) region between IIx and IIb, extending across the entire IIx gene and into its promoter. The expression of the xII NAT was positively correlated with IIb pre-mRNA (R = +0.8), and negatively correlated with IIx pre-mRNA (R = -0.8). Transcription mapping of the IIx-IIb IG region revealed the generation of sense IIb and xII NATs from a single promoter region. This bidirectional promoter is highly conserved among species and contains several regulatory elements that may be implicated in its regulation. These results suggest that the IIx and the IIb genes are physically and functionally linked via the bidirectional promoter. In order for the IIx MHC gene to be regulated, a feedback mechanism from the IG xII NAT is needed. In conclusion, the IG bidirectional promoter generating antisense RNA appears to be essential for the coordinated regulation of the skeletal muscle MHC genes during dynamic phenotype shifts.
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Affiliation(s)
- Chiara Rinaldi
- Physiology and Biophysics Department, University of California Irvine, Irvine, CA, USA
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17
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18
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Gupta MP. Factors controlling cardiac myosin-isoform shift during hypertrophy and heart failure. J Mol Cell Cardiol 2007; 43:388-403. [PMID: 17720186 PMCID: PMC2701247 DOI: 10.1016/j.yjmcc.2007.07.045] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 06/25/2007] [Accepted: 07/10/2007] [Indexed: 12/18/2022]
Abstract
Myosin is a molecular motor, which interacts with actin to convert the energy from ATP hydrolysis into mechanical work. In cardiac myocytes, two myosin isoforms are expressed and their relative distribution changes in different developmental and pathophysiologic conditions of the heart. It has been realized for a long time that a shift in myosin isoforms plays a major role in regulating myocardial contractile activity. With the recent evidence implicating that alteration in myosin isoform ratio may be eventually beneficial for the treatment of a stressed heart, a new interest has developed to find out ways of controlling the myosin isoform shift. This article reviews the published data describing the role of myosin isoforms in the heart and highlighting the importance of various factors shown to influence myosin isofrom shift during physiology and disease states of the heart.
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Affiliation(s)
- Mahesh P Gupta
- Department of Surgery, Basic Science Division, MC5040, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, USA.
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19
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Tajsharghi H, Darin N, Rekabdar E, Kyllerman M, Wahlström J, Martinsson T, Oldfors A. Mutations and sequence variation in the human myosin heavy chain IIa gene (MYH2). Eur J Hum Genet 2005; 13:617-22. [PMID: 15741996 DOI: 10.1038/sj.ejhg.5201375] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We recently described a new autosomal dominant myopathy associated with a missense mutation in the myosin heavy chain (MyHC) IIa gene (MYH2). In this study, we performed mutation analysis of MYH2 in eight Swedish patients with familial myopathy of unknown cause. In two of the eight index cases, we identified novel heterozygous missense mutations in MYH2, one in each case: V970I and L1061V. The mutations were located in subfragment 2 of the MyHC and they changed highly conserved residues. Most family members carrying the mutations had signs and symptoms consisting mainly of mild muscle weakness and myalgia. In addition, we analyzed the extent and distribution of nucleotide variation in MYH2 in 50 blood donors, who served as controls, by the complete sequencing of all 38 exons comprising the coding region. We identified only six polymorphic sites, five of which were synonymous polymorphisms. One variant, which occurred at an allele frequency of 0.01, was identical to the L1061V that was also found in one of the families with myopathy. The results of the analysis of normal variation indicate that there is strong selective pressure against mutations in MYH2. On the basis of these results, we suggest that MyHC genes should be regarded as candidate genes in cases of hereditary myopathies of unknown etiology.
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Affiliation(s)
- Homa Tajsharghi
- Departments of Pathology, Sahlgrenska University Hospital, Göteborg, Sweden.
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20
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Sun YM, Da Costa N, Chang KC. Cluster characterisation and temporal expression of porcine sarcomeric myosin heavy chain genes. J Muscle Res Cell Motil 2004; 24:561-70. [PMID: 14870971 DOI: 10.1023/b:jure.0000009895.03111.b3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Members of the myosin heavy chain (MyHC) gene family are subjected to temporal regulation of gene switching during development. One strategy to the identification of cis-acting regulatory elements that are involved in temporal or fibre-type specific regulation is to undertake a comparative analysis of the MyHC gene family between the pig, an important target species, and other mammals, like human whose entire genome has been recently sequenced. Towards this end, we report here on the isolation, and characterisation of the porcine cardiac (MyHC slow/beta and alpha) and skeletal MyHC (embryonic, 2a, 2x, 2b and perinatal) gene clusters, and their structural comparisons with mouse and human clusters. The genome organisation of both clusters in the pig, human and mouse is conserved as having the same gene order, similar intergenic distances, and in the same head-to-tail orientation. For a period of pre-natal muscle growth, relative expression of MyHC isoforms, as determined by TaqMan real-time RT-PCR, correlated with the gene order in the skeletal MyHC cluster (embryonic > 2a > 2x > 2b) suggesting the possible presence of DNA elements on the same side as the MyHC embryonic gene that direct temporal regulation.
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Affiliation(s)
- Y M Sun
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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21
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Haddad F, Bodell PW, Qin AX, Giger JM, Baldwin KM. Role of antisense RNA in coordinating cardiac myosin heavy chain gene switching. J Biol Chem 2003; 278:37132-8. [PMID: 12851393 DOI: 10.1074/jbc.m305911200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel mechanism of regulation of cardiac alpha and beta myosin heavy chain gene by naturally occurring antisense transcription was elucidated via pre-mRNA analysis. Herein, we report the expression of an antisense beta myosin heavy chain RNA in the normal rodent myocardium. The pattern of expression of the antisense betaMHC RNA (beta RNA) under altered thyroid state and in diabetes directly correlates with that of the alpha pre-mRNA/mRNA, whereas it negatively correlates with the beta mRNA expression. Rapid amplification of the 5' end shows that this antisense transcript originates 2 kb downstream of the beta gene, and it is transcribed across the entire beta gene from the opposite strand. Our results demonstrate that the beta-alpha myosin heavy chain intergenic DNA possesses a bidirectional transcriptional activity, one direction transcribing the alpha gene, and the opposite direction transcribing the antisense beta RNA. This process turns on the alpha expression, and it simultaneously turns off that of the beta and thus coordinates alpha and beta expression in an opposite fashion. Comparative analyses of the intergenic DNA sequence across five mammalian species revealed a conserved region that is proposed to be a common regulatory region for the alpha and antisense beta promoter. This finding unravels the mechanism of cardiac alpha-beta gene switching and implicates the role of cardiac myosin gene organization with their function.
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Affiliation(s)
- Fadia Haddad
- Department of Physiology and Biophysics, University of California, Irvine, California 92697-4560, USA
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22
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Abstract
BACKGROUND Chronic cocaine users can have as much as a 69% increase in left ventricular muscle mass without associated increases in arterial blood pressure, heart rate, renin, aldosterone, or cortisol. We determined whether cocaine directly increases cardiomyocyte protein content and whether protein kinase C is important in this process. METHODS AND RESULTS Adult rat cardiomyocytes were isolated and grown in cultures. In Series I experiments, cocaine, 10(-8) to 10(-6) M, or vehicle, in the absence or presence of phentolamine or metoprolol, was added to each culture and the cells were subsequently harvested. In Series II, cocaine, 10(-6) M, cocaine, 10(-6) M, plus bisindolylmaleimide, 10(-6) M, a protein kinase C inhibitor, or vehicle were added to each culture and the cells subsequently harvested. We determined the total protein content, the content of alpha-myosin and fetal beta-myosin heavy-chain protein, and the presence of protein kinase C isoforms in the cardiomyocyte soluble and particulate fractions. Protein kinase C translocation from the soluble to particulate fraction is indicative of activation. In Series III, we determined the cocaine effects on ERK, SAPK/JNK, and p38. In Series I, cocaine, 10(-8) to 10(-6) M, dose-dependently increased myocyte protein content by as much as 28%+/-2% (P<.001) and fetal beta-myosin heavy-chain protein content by 80%+/-2% (P<.001). Neither phentolamine nor metoprolol inhibited this process. In Series II, we determined that ventricular myocytes contain alpha (alpha), beta (beta), delta (delta), epsilon (epsilon), and zeta (zeta) protein kinase C isoforms. Cocaine, 10(-6) M, caused a 45+/-5% increase (P<.001) in protein kinase Calpha in the particulate fraction. The addition of a protein kinase C inhibitor to the myocyte cultures prevented the cocaine-induced translocation of protein kinase Calpha and limited the increase in beta-myosin heavy-chain protein content by >75% (P<.001). However, cocaine did not increase the phosphorylation of ERK, SAPK/JNK or p38 in Series III. CONCLUSIONS Cocaine increases adult cardiomyocyte protein content by protein kinase Calpha-dependent mechanisms, and this process can contribute to the cardiac hypertrophy and cardiomyopathy that results from chronic cocaine use.
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Affiliation(s)
- Robert J Henning
- Department of Medicine, University of South Florida College of Medicine and the James A. Haley Hospital, Tampa, Florida, USA.
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23
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Huey KA, Haddad F, Qin AX, Baldwin KM. Transcriptional regulation of the type I myosin heavy chain gene in denervated rat soleus. Am J Physiol Cell Physiol 2003; 284:C738-48. [PMID: 12444021 DOI: 10.1152/ajpcell.00389.2002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Denervation (DEN) of rat soleus is associated with a decreased expression of slow type I myosin heavy chain (MHC) and an increased expression of the faster MHC isoforms. The molecular mechanisms behind these shifts remain unclear. We first investigated endogenous transcriptional activity of the type I MHC gene in normal and denervated soleus muscles via pre-mRNA analysis. Our results suggest that the type I MHC gene is regulated via transcriptional processes in the denervated soleus. Deletion and mutational analysis of the rat type I MHC promoter was then used to identify cis elements or regions of the promoter involved in this response. DEN significantly decreased in vivo activity of the -3,500, -2,500, -914, -408, -299, and -215 bp type I MHC promoters, relative to the alpha-skeletal actin promoter. In contrast, normalized -171 promoter activity was unchanged. Mutation of the betae3 element (-214/-190) in the -215 promoter and deletion of this element (-171 promoter) blunted type I downregulation with DEN. In contrast, betae3 mutation in the -408 promoters was not effective in attenuating the DEN response, suggesting the existence of additional DEN-responsive sites between -408 and -215. Western blotting and gel mobility supershift assays demonstrated decreased expression and DNA binding of transcription enhancer factor 1 (TEF-1) with DEN, suggesting that this decrease may contribute to type I MHC downregulation in denervated muscle.
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Affiliation(s)
- K A Huey
- Department of Physiology and Biophysics, University of California, Irvine 92697, USA
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24
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Abstract
Myogenesis has been a system central to investigations on mechanisms of diversification within groups of differentiating cells. Diversity among cell types has been well described in striated muscle tissue at the protein and enzymatic-function levels for decades, but it is only in recent years that some understanding of the molecular mechanisms responsible for this diversity has begun to emerge. Study of the expression of the slow isoforms of the myosin heavy chain has contributed to our understanding of how cell diversity arises within skeletal and cardiac muscle. Slow MyHc isoforms are developmentally responsive to a number of cues provided by the nervous systems, the endocrine system and, later in development, to functional demands on these developing tissues. Perhaps most informative have been studies on the mechanism for regulation of slow MyHc expression in mammals and birds where studies on the calcineurin-NF-AT pathways and nuclear hormone action have been shown to control MyHC gene expression in skeletal muscle and in the developing heart. The mechanisms involved in cell diversification in myogenesis are undoubtedly more varied and complex than those currently offered to explain cell diversification, but these recent studies have broadened our understanding of the interplay between the nervous system, the endocrine system and cell lineages in controlling cell diversification. Greater focus on the first fibers and cardiomyocytes to form in the embryo are likely to bring additional insights into the mechanism crucial for establishing the patterns of diversity required for successful formation of embryonic tissues.
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Affiliation(s)
- Frank E Stockdale
- Stanford Medical Center, CCSR 1145, Stanford, California 94305-5151, USA
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25
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Wigmore PM, Evans DJR. Molecular and cellular mechanisms involved in the generation of fiber diversity during myogenesis. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 216:175-232. [PMID: 12049208 DOI: 10.1016/s0074-7696(02)16006-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Skeletal muscles have a characteristic proportion and distribution of fiber types, a pattern which is set up early in development. It is becoming clear that different mechanisms produce this pattern during early and late stages of myogenesis. In addition, there are significant differences between the formation of muscles in head and those found in rest of the body. Early fiber type differentiation is dependent upon an interplay between patterning systems which include the Wnt and Hox gene families and different myoblast populations. During later stages, innervation, hormones, and functional demand increasingly act to determine fiber type, but individual muscles still retain an intrinsic commitment to form particular fiber types. Head muscle is the only muscle not derived from the somites and follows a different development pathway which leads to the formation of particular fiber types not found elsewhere. This review discusses the formation of fiber types in both head and other muscles using results from both chick and mammalian systems.
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Affiliation(s)
- Peter M Wigmore
- School of Biomedical Sciences, Queen's Medical Centre, Nottingham, United Kingdom
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26
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Smerdu V, Erzen I. Dynamic nature of fibre-type specific expression of myosin heavy chain transcripts in 14 different human skeletal muscles. J Muscle Res Cell Motil 2002; 22:647-55. [PMID: 12222825 DOI: 10.1023/a:1016337806308] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The main goal of this study was to find out, whether the appearance of fibres without evident myosin heavy chain (MyHC) transcript expression (negative fibres) implies the existence of additional MyHC transcripts in human muscle fibres. Fourteen different skeletal muscles were analysed also to verify how MyHC transcript expression matches histochemical phenotypes of fibres. For this purpose, the expression of beta-slow, 2a and 2x MyHC transcripts, demonstrated by in situ hybridisation technique, was analysed within type I, IIC, IIA, IIAX and IIX fibres, determined according to the activity of myofibrillar ATPase. Additionally, MyHC isoform expression was immunohistochemically demonstrated and metabolic profiles of negative fibres were estimated. From a total of 4444 muscle fibres analysed, only 0.8% of fibres were negative, among them type I prevailed, the remainder were type IIA and IIX fibres. The majority of fibres expressed only beta, 2a and 2x MyHC transcripts and they mostly matched type I, IIA and IIX fibres respectively, but two minor hybrid fibre groups (beta/2a and 2ax) exhibited variable histochemical phenotype. The infrequency, the prevailing oxidative-glycolytic metabolic profile of negative type I fibres and frequent co-appearance with transitional type IIC fibres imply that the negative fibres rather result from fibre type transition than express an additional slow or even 2b MyHC transcripts. The appearance of hybrid and mismatched fibres additionally indicates that fibre type transition occurs also in presumably normal skeletal muscles, what enables the muscles to tune even with minimal changes in mechanical demands.
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Affiliation(s)
- V Smerdu
- Institute of Anatomy, Medical Faculty, University of Ljubljana, Slovenia.
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27
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Abstract
SUMMARY
Extraocular muscle exhibits higher-velocity and lower-tension contractions than other vertebrate striated muscles. These distinctive physiological properties are associated with the expression of a novel extraocular myosin heavy chain (MYH). Encoded by the MYH13 gene, the extraocular myosin heavy chain is a member of the fast/developmental MYH gene cluster on human chromosome 17 and the syntenic MYH cluster on mouse chromosome 11. Comparison of cDNA sequences reveals that MYH13 also encodes the atypical MYH identified in laryngeal muscles, which have similar fast contractile properties. Comparing the MYH13 sequence with the other members of the fast/developmental cluster, the slow/cardiac MYH genes and two orphan skeletal MYH genes in the human genome provides insights into the origins of specialization in striated muscle myosins. Specifically, these studies indicate (i) that the extraocular myosin is not derived from the adult fast skeletal muscle myosins, but was the first member of the fast/developmental MYH gene cluster to diverge and specialize, (ii) that the motor and rod domains of the MYH13 have evolved under different selective pressures and (iii) that the MYH13 gene has been largely insulated from genomic events that have shaped other members of the fast/developmental cluster. In addition, phylogenetic footprinting suggests that regulation of the extraocular MYH gene is not governed primarily by myogenic factors, but by a hierarchical network of regulatory factors that relate its expression to the development of extraocular muscles.
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Affiliation(s)
- Fred Schachat
- Department of Cell Biology, Division of Physiology, Duke University Medical School, Durham, NC 27710, USA.
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28
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Desjardins PR, Burkman JM, Shrager JB, Allmond LA, Stedman HH. Evolutionary implications of three novel members of the human sarcomeric myosin heavy chain gene family. Mol Biol Evol 2002; 19:375-93. [PMID: 11919279 DOI: 10.1093/oxfordjournals.molbev.a004093] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sarcomeric myosin heavy chain (MyHC) is the major contractile protein of striated muscle. Six tandemly linked skeletal MyHC genes on chromosome 17 and two cardiac MyHC genes on chromosome 14 have been previously described in the human genome. We report the identification of three novel human sarcomeric MyHC genes on chromosomes 3, 7, and 20, which are notable for their atypical size and intron-exon structure. Two of the encoded proteins are structurally most like the slow-beta MyHC, whereas the third one is closest to the adult fast IIb isoform. Data from pairwise comparisons of aligned coding sequences imply the existence of ancestral genomes with four sarcomeric genes before the emergence of a dedicated smooth muscle MyHC gene. To further address the evolutionary relationships of the distinct sarcomeric and nonsarcomeric rod sequences, we have identified and further annotated human genomic DNA sequences corresponding to 14 class-II MyHCs. An extensive analysis provides a timeline for intron gain and loss, gene contraction and expansion, and gene conversion among genes encoding class-II myosins. One of the novel human genes is found to have introns at positions shared only with the molluscan catchin/MyHC gene, providing evidence for the structure of a pre-Cambrian ancestral gene.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Chromosomes, Human, Pair 20/genetics
- Chromosomes, Human, Pair 3/genetics
- Chromosomes, Human, Pair 7/genetics
- Cloning, Molecular
- DNA, Complementary
- Drosophila/genetics
- Evolution, Molecular
- Gene Conversion
- Gene Deletion
- Humans
- Molecular Sequence Data
- Muscle, Skeletal/chemistry
- Myosin Heavy Chains/genetics
- Repetitive Sequences, Nucleic Acid
- Sarcomeres/chemistry
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Philippe R Desjardins
- Department of Surgery, School of Medicine, University of Pennsylvania, 421 Curie Blvd., Philadelphia, PA 19104, USA
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29
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Huey KA, Roy RR, Haddad F, Edgerton VR, Baldwin KM. Transcriptional regulation of the type I myosin heavy chain promoter in inactive rat soleus. Am J Physiol Cell Physiol 2002; 282:C528-37. [PMID: 11832338 DOI: 10.1152/ajpcell.00355.2001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic muscle inactivity with spinal cord isolation (SI) decreases expression of slow type I myosin heavy chain (MHC) while increasing expression of the faster MHC isoforms, primarily IIx. The purpose of this study was to determine whether type I MHC downregulation in the soleus muscle of SI rats is regulated transcriptionally and to identify cis-acting elements or regions of the rat type I MHC gene promoter involved in this response. One week of SI significantly decreased in vivo activity of the -3500-, -408-, -299-, -215-, and -171-bp type I MHC promoters. The activity of all tested deletions of the type I MHC promoter, relative to the human skeletal alpha-actin promoter, were significantly reduced in the SI soleus, except activity of the -171-bp promoter, which increased. Mutation of the betae3 element (-214/-190 bp) in the -215- and -408-bp promoters and deletion of this element (-171-bp promoter) attenuated type I downregulation with SI. Gel mobility shift assays demonstrated a decrease in transcription enhancer factor-1 binding to the betae3 element with SI, despite an increase in total binding to this region. These results demonstrate that type I MHC downregulation with SI is transcriptionally regulated and suggest that interactions between transcription enhancer factor-1 and the betae3 element are likely involved in this response.
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Affiliation(s)
- K A Huey
- Department of Physiology and Biophysics, University of California-Irvine, Irvine, CA 92697, USA
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30
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Abstract
This article reviews the complexity, expression, genetics, regulation, function, and evolution of the avian myosin heavy chain (MyHC). The majority of pertinent studies thus far published have focussed on domestic chicken and, to a much lesser extent, Japanese quail. Where possible, information available about wild species has also been incorporated into this review. While studies of additional species might modify current interpretations, existing data suggest that some fundamental properties of myosin proteins and genes in birds are unique among higher vertebrates. We compare the characteristics of myosins in birds to those of mammals, and discuss potential molecular mechanisms and evolutionary forces that may explain how avian MyHCs acquired these properties.
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Affiliation(s)
- E Bandman
- Department of Food Science and Technology, University of California, Davis, California 95616, USA.
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31
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Nguyen T, Shrager J, Kaiser L, Mei L, Daood M, Watchko J, Rubinstein N, Levine S. Developmental myosin heavy chains in the adult human diaphragm: coexpression patterns and effect of COPD. J Appl Physiol (1985) 2000; 88:1446-56. [PMID: 10749841 DOI: 10.1152/jappl.2000.88.4.1446] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In preliminary experiments we noted developmental (i.e., embryonic and neonatal) myosin heavy chains (MHCs) in the diaphragms of patients with severe chronic obstructive pulmonary disease (COPD). We hypothesized that this finding represented new fiber formation secondary to injury associated with the mechanical stress of COPD or previously undescribed MHCs in the human diaphragm. To distinguish between these possibilities, we analyzed diaphragmatic biopsies obtained from 9 patients with severe COPD (forced expiratory volume in 1 s = 21 +/- 2% predicted, residual volume = 283 +/- 22% predicted) and 10 age-matched controls. First, using immunocytochemistry with specific monoclonal antibodies, we noted that control diaphragms had greater proportions of fibers expressing embryonic (50 +/- 2 vs. 28 +/- 3%, P < 0.0001) and neonatal (52 +/- 2 vs. 32 +/- 3%, P < 0.001) MHCs than COPD diaphragms. Second, SDS-PAGE demonstrated that these developmental MHCs represented only a very small fraction of the diaphragmatic MHC content. Third, the RT-PCR demonstrated mRNA coding for embryonic and neonatal MHCs in COPD and control diaphragms. Last, COPD and control diaphragms exhibited normal histology on light microscopy. We conclude that the presence of developmental MHC isoforms does not indicate new fiber formation in diaphragms of patients with severe COPD. Although these results represent the first systematic description of embryonic and neonatal MHCs in normal adult human diaphragms, their function remains to be elucidated.
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Affiliation(s)
- T Nguyen
- Medical, Surgical, and Research Services, Philadelphia Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
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32
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Croissant JD, Carpenter S, Bader D. Identification and genomic cloning of CMHC1. A unique myosin heavy chain expressed exclusively in the developing chicken heart. J Biol Chem 2000; 275:1944-51. [PMID: 10636896 DOI: 10.1074/jbc.275.3.1944] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report the identification and cloning of a unique chick myosin heavy chain (CMHC1) that is expressed exclusively in the heart during embryogenesis. Using primers specific to myosin heavy chains, we used reverse transcriptase-polymerase chain reaction to clone and isolate CMHC1 from embryonic day 10 chicken heart RNA. Sequence analysis indicated that CMHC1 was a novel member of the myosin heavy chain family. Expression of the CMHC1 transcripts was detected in Hamburger Hamilton stage 10 chick embryos in the fusing myocardium. Expression of CMHC1 was maintained at high levels throughout the tubular heart of later stage embryos. Reverse transcriptase-polymerase chain reaction and in situ hybridizations failed to detect CMHC1 transcripts in the developing somites, limb buds, or skeletal musculature at any stage of chick development. Genomic CMHC1 clones have been isolated that contain sequences approximately 5.2 kilobase upstream of the presumptive CMHC1 transcription start site. Portions of the upstream regulatory region induced a 21-fold increase in reporter gene expression in primary cardiomyocytes. Because of its unique cardiac-restricted expression, CMHC1 will provide an excellent model system to study the molecular mechanisms required for the early developmental regulation of heart-specific genes.
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Affiliation(s)
- J D Croissant
- Gladys P. Stahlman Cardiovascular Research Laboratory, Vanderbilt University Medical Center, Nashville, Tennessee 37212-6300, USA
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33
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Wendel B, Reinhard R, Wachtendorf U, Zacharzowsky UB, Osterziel KJ, Schulte HD, Haase H, Hoehe MR, Morano I. The human ?-myosin heavy chain gene: Sequence diversity and functional characteristics of the protein. J Cell Biochem 2000. [DOI: 10.1002/1097-4644(20001215)79:4<566::aid-jcb50>3.0.co;2-e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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34
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Lu BD, Allen DL, Leinwand LA, Lyons GE. Spatial and temporal changes in myosin heavy chain gene expression in skeletal muscle development. Dev Biol 1999; 216:312-26. [PMID: 10588881 DOI: 10.1006/dbio.1999.9488] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Seven myosin heavy chains (MyHC) are expressed in mammalian skeletal muscle in spatially and temporally regulated patterns. The timing, distribution, and quantitation of MyHC expression during development and early postnatal life of the mouse are reported here. The three adult fast MyHC RNAs (IIa, IIb, and IId/x) are expressed in the mouse embryo and each mRNA has a distinct temporal and spatial distribution. In situ hybridization analysis demonstrates expression of IIb mRNA by 14.5 dpc, which proceeds developmentally in a rostral to caudal pattern. IId/x and IIa mRNAs are detectable 2 days later. Ribonuclease protection assays demonstrate that the three adult fast genes are expressed at approximately equal levels relative to each other in the embryo but at quite low levels relative to the two developmental isoforms, embryonic and perinatal. Just after birth major changes in the relative proportions of different MyHC RNAs and protein occur. In all cases, RNA expression and protein expression appear coincident. The changes in MyHC RNA and protein expression are distinct in different muscles and are restricted in some cases to particular regions of the muscle and do not always reflect their distribution in the adult.
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Affiliation(s)
- B D Lu
- Department of Microbiology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA
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35
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Han Y, Wang J, Fischman DA, Biller HF, Sanders I. Slow tonic muscle fibers in the thyroarytenoid muscles of human vocal folds; a possible specialization for speech. THE ANATOMICAL RECORD 1999; 256:146-57. [PMID: 10486512 DOI: 10.1002/(sici)1097-0185(19991001)256:2<146::aid-ar5>3.0.co;2-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Most of the sounds of human speech are produced by vibration of the vocal folds, yet the biomechanics and control of these vibrations are poorly understood. In this study the muscle within the vocal fold, the thyroarytenoid muscle (TA), was examined for the presence and distribution of slow tonic muscle fibers (STF), a rare muscle fiber type with unique contraction properties. Nine human TAs were frozen and serially sectioned in the frontal plane. The presence and distribution pattern of STF in each TA were examined by immunofluorescence microscopy using the monoclonal antibodies (mAb) ALD-19 and ALD-58 which react with the slow tonic myosin heavy chain (MyHC) isoform. In addition, TA muscle samples from adjacent frozen sections were also examined for slow tonic MyHC isoform by electrophoretic immunoblotting. STF were detected in all nine TAs and the presence of slow tonic MyHC isoform was confirmed in the immunoblots. The STF were distributed predominantly in the medial aspect of the TA, a distinct muscle compartment called the vocalis which is the vibrating part of the vocal fold. STF do not contract with a twitch like most muscle fibers, instead, their contractions are prolonged, stable, precisely controlled, and fatigue resistant. The human voice is characterized by a stable sound with a wide frequency spectrum that can be precisely modulated and the STF may contribute to this ability. At present, the evidence suggests that STF are not presented in the vocal folds of other mammals (including other primates), therefore STF may be a unique human specialization for speech.
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Affiliation(s)
- Y Han
- Department of Otolaryngology, The Mount Sinai Medical Center, New York, New York 10029, USA
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36
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Weiss A, Schiaffino S, Leinwand LA. Comparative sequence analysis of the complete human sarcomeric myosin heavy chain family: implications for functional diversity. J Mol Biol 1999; 290:61-75. [PMID: 10388558 DOI: 10.1006/jmbi.1999.2865] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The conventional myosin motor proteins that drive mammalian skeletal and cardiac muscle contraction include eight sarcomeric myosin heavy chain (MyHC) isoforms. Six skeletal MyHCs are encoded by genes found in tightly linked clusters on human and mouse chromosomes 17 and 11, respectively. The full coding regions of only two out of six mammalian skeletal MyHCs had been sequenced prior to this work. In an effort to assess the extent of sequence diversity within the human MyHC family we present new full-length coding sequences corresponding to four additional human genes: MyHC-IIb, MyHC-extraocular, MyHC-IIa and MyHC-IIx/d. This represents the first opportunity to compare the full coding sequences of all eight sarcomeric MyHC isoforms within a vertebrate organism. Sequence variability has been analyzed in the context of available structure/function data with an emphasis on potential functional diversity within the family. Results indicate that functional diversity among MyHCs is likely to be accomplished by having small pockets of sequence diversity in an otherwise highly conserved molecule.
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Affiliation(s)
- A Weiss
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, 10461, USA
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37
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Abstract
Familial hypertrophic cardiomyopathy (FHC) is a cardiomyopathy that occurs in 0.2% of the general population. It is characterized by asymmetrical hypertrophy of the ventricle, predominantly the intraventricular septum. FHC is caused by genetic mutations in several of the sarcomeric proteins, such as myosin heavy chain, troponin T, troponin I, alpha-tropomyosin, essential and regulatory light chains of myosin, and the cardiac myosin-binding protein C. FHC is genetically heterogeneous, and, therefore, it is associated with a very diverse clinical presentation in terms of altered cardiac structure and clinical manifestations. The most severe manifestation is sudden death. The purpose of this article is to provide the reader with new insights into the genetic mutations that give rise to FHC and to discuss risk factors that are associated with severe hypertrophy and sudden death in this population.
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Affiliation(s)
- M R Piano
- Department of Medical-Surgical Nursing, University of Illinois, Chicago, USA
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38
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Martinsson T, Darin N, Kyllerman M, Oldfors A, Hallberg B, Wahlström J. Dominant hereditary inclusion-body myopathy gene (IBM3) maps to chromosome region 17p13.1. Am J Hum Genet 1999; 64:1420-6. [PMID: 10205275 PMCID: PMC1377880 DOI: 10.1086/302375] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
We recently described an autosomal dominant inclusion-body myopathy characterized by congenital joint contractures, external ophthalmoplegia, and predominantly proximal muscle weakness. A whole-genome scan, performed with 161 polymorphic markers and with DNA from 40 members of one family, indicated strong linkage for markers on chromosome 17p. After analyses with additional markers in the region and with DNA from eight additional family members, a maximum LOD score (Zmax) was detected for marker D17S1303 (Zmax=7.38; recombination fraction (theta)=0). Haplotype analyses showed that the locus (Genome Database locus name: IBM3) is flanked distally by marker D17S945 and proximally by marker D17S969. The positions of cytogenetically localized flanking markers suggest that the location of the IBM3 gene is in chromosome region 17p13.1. Radiation hybrid mapping showed that IBM3 is located in a 2-Mb chromosomal region and that the myosin heavy-chain (MHC) gene cluster, consisting of at least six genes, co-localizes to the same region. This localization raises the possibility that one of the MHC genes clustered in this region may be involved in this disorder.
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Affiliation(s)
- T Martinsson
- Department of Clinical Genetics, Sahlgrenska University Hospital/Ostra, S-416 85 Gothenburg, Sweden.
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39
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Barton PJ, Cullen ME, Townsend PJ, Brand NJ, Mullen AJ, Norman DA, Bhavsar PK, Yacoub MH. Close physical linkage of human troponin genes: organization, sequence, and expression of the locus encoding cardiac troponin I and slow skeletal troponin T. Genomics 1999; 57:102-9. [PMID: 10191089 DOI: 10.1006/geno.1998.5702] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Based on chromosomal mapping data, we recently revealed an unexpected linkage of troponin genes in the human genome: the six genes encoding striated muscle troponin I and troponin T isoforms are located at three chromosomal sites, each of which carries a troponin I-troponin T gene pair. Here we have investigated the organization of these genes at the DNA level in isolated P1 and PAC genomic clones and demonstrate close physical linkage in two cases through the isolation of individual clones containing a complete troponin I-troponin T gene pair. As an initial step toward fully characterizing this pattern of linkage, we have determined the organization and complete sequence of the locus encoding cardiac troponin I and slow skeletal troponin T and thereby also provide the first determination of the structure and sequence of a slow skeletal troponin T gene. Our data show that the genes are organized head to tail and are separated by only 2.6 kb of intervening sequence. In contrast to other troponin genes, and despite their close proximity, the cardiac troponin I and slow skeletal troponin T genes show independent tissue-specific expression. Such close physical linkage has implications for the evolution of the troponin gene families, for their regulation, and for the analysis of mutations implicated in cardiomyopathy.
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Affiliation(s)
- P J Barton
- Imperial College School of Medicine, National Heart and Lung Institute, Dovehouse Street, London, SW3 6LY, United Kingdom.
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40
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Weiss A, McDonough D, Wertman B, Acakpo-Satchivi L, Montgomery K, Kucherlapati R, Leinwand L, Krauter K. Organization of human and mouse skeletal myosin heavy chain gene clusters is highly conserved. Proc Natl Acad Sci U S A 1999; 96:2958-63. [PMID: 10077619 PMCID: PMC15877 DOI: 10.1073/pnas.96.6.2958] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin heavy chains (MyHCs) are highly conserved ubiquitous actin-based motor proteins that drive a wide range of motile processes in eukaryotic cells. MyHC isoforms expressed in skeletal muscles are encoded by a multigene family that is clustered on syntenic regions of human and mouse chromosomes 17 and 11, respectively. In an effort to gain a better understanding of the genomic organization of the skeletal MyHC genes and its effects on the regulation, function, and molecular genetics of this multigene family, we have constructed high-resolution physical maps of both human and mouse loci using PCR-based marker content mapping of P1-artificial chromosome clones. Genes encoding six MyHC isoforms have been mapped with respect to their linear order and transcriptional orientations within a 350-kb region in both human and mouse. These maps reveal that the order, transcriptional orientation, and relative intergenic distances of these genes are remarkably conserved between these species. Unlike many clustered gene families, this order does not reflect the known temporal expression patterns of these genes. However, the conservation of gene organization since the estimated divergence of these species (approximately 75-110 million years ago) suggests that the physical organization of these genes may be significant for their regulation and function.
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Affiliation(s)
- A Weiss
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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41
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Smith KP, Moen PT, Wydner KL, Coleman JR, Lawrence JB. Processing of endogenous pre-mRNAs in association with SC-35 domains is gene specific. J Biophys Biochem Cytol 1999; 144:617-29. [PMID: 10037785 PMCID: PMC2132926 DOI: 10.1083/jcb.144.4.617] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Analysis of six endogenous pre-mRNAs demonstrates that localization at the periphery or within splicing factor-rich (SC-35) domains is not restricted to a few unusually abundant pre-mRNAs, but is apparently a more common paradigm of many protein-coding genes. Different genes are preferentially transcribed and their RNAs processed in different compartments relative to SC-35 domains. These differences do not simply correlate with the complexity, nuclear abundance, or position within overall nuclear space. The distribution of spliceosome assembly factor SC-35 did not simply mirror the distribution of individual pre-mRNAs, but rather suggested that individual domains contain both specific pre-mRNA(s) as well as excess splicing factors. This is consistent with a multifunctional compartment, to which some gene loci and their RNAs have access and others do not. Despite similar molar abundance in muscle fiber nuclei, nascent transcript "trees" of highly complex dystrophin RNA are cotranscriptionally spliced outside of SC-35 domains, whereas posttranscriptional "tracks" of more mature myosin heavy chain transcripts overlap domains. Further analyses supported that endogenous pre-mRNAs exhibit distinct structural organization that may reflect not only the expression and complexity of the gene, but also constraints of its chromosomal context and kinetics of its RNA metabolism.
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Affiliation(s)
- K P Smith
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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42
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Morano M, Boels P, Haworth SG, Haase H, Morano I. Expression and function of atrial myosin light chain 1 in the porcine right ventricle of normal and pulmonary hypertensive animals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 453:481-8; discussion 488-9. [PMID: 9889860 DOI: 10.1007/978-1-4684-6039-1_53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We investigated the expression of atrial myosin light chain 1 (ALC-1) and myosin cycling kinetics in the normal and hypertrophied right ventricle of the neonatal porcine heart. Right ventricular hypertrophy was induced by exposing piglets immediately after birth to hypobaric hypoxia for 3 days. Control piglets were kept under normal conditions for the same time. ALC-1 expression in the hypertrophied right ventricle was 16.9%. No ALC-1 expression could be observed in the right ventricle of control pigs. Force-velocity of chemically skinned right ventricular fibers was analyzed in order to examine the functional role of ALC-1 expression on myosin cross-bridge kinetics. Force generation per cross-section at maximal Ca2+ activation (pCa 4.5) was significantly higher in the hypertrophied group. Maximal shortening velocity (Vmax) of skinned fibers increased statistically significant from 0.69 muscle length per second (ML/s) in the control to 1.2 ML/s in the hypertrophied right ventricle. We conclude that the expression of ALC-1 in the hypertrophied ventricle of neonatal pigs increased cross-bridge cycling kinetics and contractility.
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Affiliation(s)
- M Morano
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
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43
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Bonne G, Carrier L, Richard P, Hainque B, Schwartz K. Familial hypertrophic cardiomyopathy: from mutations to functional defects. Circ Res 1998; 83:580-93. [PMID: 9742053 DOI: 10.1161/01.res.83.6.580] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertrophic cardiomyopathy is characterized by left and/or right ventricular hypertrophy, which is usually asymmetric and involves the interventricular septum. Typical morphological changes include myocyte hypertrophy and disarray surrounding the areas of increased loose connective tissue. Arrhythmias and premature sudden deaths are common. Hypertrophic cardiomyopathy is familial in the majority of cases and is transmitted as an autosomal-dominant trait. The results of molecular genetics studies have shown that familial hypertrophic cardiomyopathy is a disease of the sarcomere involving mutations in 7 different genes encoding proteins of the myofibrillar apparatus: ss-myosin heavy chain, ventricular myosin essential light chain, ventricular myosin regulatory light chain, cardiac troponin T, cardiac troponin I, alpha-tropomyosin, and cardiac myosin binding protein C. In addition to this locus heterogeneity, there is a wide allelic heterogeneity, since numerous mutations have been found in all these genes. The recent development of animal models and of in vitro analyses have allowed a better understanding of the pathophysiological mechanisms associated with familial hypertrophic cardiomyopathy. One can thus tentatively draw the following cascade of events: The mutation leads to a poison polypeptide that would be incorporated into the sarcomere. This would alter the sarcomeric function that would result (1) in an altered cardiac function and then (2) in the alteration of the sarcomeric and myocyte structure. Some mutations induce functional impairment and support the pathogenesis hypothesis of a "hypocontractile" state followed by compensatory hypertrophy. Other mutations induce cardiac hyperfunction and determine a "hypercontractile" state that would directly induce cardiac hypertrophy. The development of other animal models and of other mechanistic studies linking the genetic mutation to functional defects are now key issues in understanding how alterations in the basic contractile unit of the cardiomyocyte alter the phenotype and the function of the heart.
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Affiliation(s)
- G Bonne
- From the INSERM Unit 153, the Service de Biochimie B, and the IFR de Physiologie et Génétique Cardiovasculaire, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
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44
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Affiliation(s)
- M R Bristow
- Division of Cardiology, School of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA
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45
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Sartorius CA, Lu BD, Acakpo-Satchivi L, Jacobsen RP, Byrnes WC, Leinwand LA. Myosin heavy chains IIa and IId are functionally distinct in the mouse. J Cell Biol 1998; 141:943-53. [PMID: 9585413 PMCID: PMC2132782 DOI: 10.1083/jcb.141.4.943] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/1998] [Revised: 04/02/1998] [Indexed: 02/07/2023] Open
Abstract
Myosin in adult murine skeletal muscle is composed primarily of three adult fast myosin heavy chain (MyHC) isoforms. These isoforms, MyHC-IIa, -IId, and -IIb, are >93% identical at the amino acid level and are broadly expressed in numerous muscles, and their genes are tightly linked. Mice with a null mutation in the MyHC-IId gene have phenotypes that include growth inhibition, muscle weakness, histological abnormalities, kyphosis (spinal curvature), and aberrant kinetics of muscle contraction and relaxation. Despite the lack of MyHC-IId, IId null mice have normal amounts of myosin in their muscles because of compensation by the MyHC-IIa gene. In each muscle examined from IId null mice, there was an increase in MyHC-IIa- containing fibers. MyHC-IIb content was unaffected in all muscles except the masseter, where its expression was extinguished in the IId null mice. Cross-sectional fiber areas, total muscle cross-sectional area, and total fiber number were affected in ways particular to each muscle. Developmental expression of adult MyHC genes remained unchanged in IId null mice. Despite this universal compensation of MyHC-IIa expression, IId null mice have severe phenotypes. We conclude that despite the similarity in sequence, MyHC-IIa and -IId have unique roles in the development and function of skeletal muscle.
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Affiliation(s)
- C A Sartorius
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
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46
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Vosberg HP. [Genetic causes of hypertrophic cardiomyopathy]. MEDIZINISCHE KLINIK (MUNICH, GERMANY : 1983) 1998; 93:252-9. [PMID: 9594535 DOI: 10.1007/bf03044801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hypertrophic cardiomyopathy is a dominantly inherited disease of the heart. Heterogeneous sets of mutations responsible for this condition have been identified in seven genes coding for proteins involved in the contraction mechanism or in the control of contraction of the myocardium. Known mutations imply structural and functional changes in the following proteins: in ventricle specific beta-myosin heavy chain, in essential and regulatory myosin light chains, in troponin subunits T and I, in alpha-tropomyosin and in myosin binding protein-C. The gene of one additional genomic HCM-locus is not known. Since two thirds or more of all cases can be traced to one of the respective genes, HCM has been classified as a disease of the cardiac sarcomere. Heterogeneity does not only exist between genes, but also within genes. At least 84 different mutations have been identified to date. More than half of them have been detected in the beta-myosin heavy chain gene. Thus, mutations in this gene account for most of the cases of HCM. The extent of data about causes is in contrast to the lack of definite knowledge about pathogenic mechanisms. Since the disorder is in many cases mild with symptoms developing frequently not before the end of the second decade, myocardial dysfunctions can presumably not directly be traced to altered contractility, but rather to effects which accumulate with a long asymptomatic lag period and which gradually lead to hypertrophy, conduction problems and ultimately to cardiac failure. The disease may be considered as an indirect and secondary response to a mildly distorted contraction process. The rapid progress in the analysis of causes suggests that the study of genes will assume a role in the context of the clinical management of HCM, in particular regarding diagnosis, prognosis, counselling of patients and families and--possibly--therapy.
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Affiliation(s)
- H P Vosberg
- Max-Planck-Institut für physiologische und klinische Forschung, Abteilung Experimentelle Kardiologie, Bad Nauheim.
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47
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Watchko JF, Daood MJ, Sieck GC. Myosin heavy chain transitions during development. Functional implications for the respiratory musculature. Comp Biochem Physiol B Biochem Mol Biol 1998; 119:459-70. [PMID: 9734330 DOI: 10.1016/s0305-0491(98)00006-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The myosin heavy chain (MHC) exists as multiple isoforms that are encoded for by a family of genes. The respiratory musculature demonstrates muscle-specific and temporally-dependent changes in MHC isoform expression during maturation. Developmental expression of MHC isoforms correlate well with postnatal changes in actomyosin ATPase activity, specific force generation (P0/CSA), maximum unloaded velocity of shortening (V0) and and fatigue resistance. More specifically, as the expression of MHCneonatal declines and MHC2A, MHC2X, and MHC2B increase, actomyosin ATPase activity, P0/CSA, V0, and muscle fatigability increase. The increase in actomyosin ATPase activity with maturation is partially offset by a postnatal increase in oxidative capacity; however, as fatigue resistance declines with development it is apparent that the energy costs of contraction are not fully matched by an increase in energy production. Developmental transitions in smooth muscle MHC phenotype also occur although their functional importance remains unclear.
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Affiliation(s)
- J F Watchko
- Department of Pediatrics, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, PA 15213, USA. watchko+@pitt.edu
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Coonar AS, McKenna WJ. Molecular genetics of familial cardiomyopathies. ADVANCES IN GENETICS 1997; 35:285-324. [PMID: 9348651 DOI: 10.1016/s0065-2660(08)60453-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- A S Coonar
- St. George's Hospital Medical School, London, United Kingdom
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Acakpo-Satchivi LJ, Edelmann W, Sartorius C, Lu BD, Wahr PA, Watkins SC, Metzger JM, Leinwand L, Kucherlapati R. Growth and muscle defects in mice lacking adult myosin heavy chain genes. J Cell Biol 1997; 139:1219-29. [PMID: 9382868 PMCID: PMC2140209 DOI: 10.1083/jcb.139.5.1219] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/1997] [Revised: 08/25/1997] [Indexed: 02/05/2023] Open
Abstract
The three adult fast myosin heavy chains (MyHCs) constitute the vast majority of the myosin in adult skeletal musculature, and are >92% identical. We describe mice carrying null mutations in each of two predominant adult fast MyHC genes, IIb and IId/x. Both null strains exhibit growth and muscle defects, but the defects are different between the two strains and do not correlate with the abundance or distribution of each gene product. For example, despite the fact that MyHC-IIb accounts for >70% of the myosin in skeletal muscle and shows the broadest distribution of expression, the phenotypes of IIb null mutants are generally milder than in the MyHC-IId/x null strain. In addition, in a muscle which expresses both IIb and IId/x MyHC in wild-type mice, the histological defects are completely different for null expression of the two genes. Most striking is that while both null strains exhibit physiological defects in isolated muscles, the defects are distinct. Muscle from IIb null mice has significantly reduced ability to generate force while IId null mouse muscle generates normal amounts of force, but has altered kinetic properties. Many of the phenotypes demonstrated by these mice are typical in human muscle disease and should provide insight into their etiology.
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Affiliation(s)
- L J Acakpo-Satchivi
- Department of Molecular Genetics, Albert Einstein College of Medicine, New York 10461, USA
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50
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Lowes BD, Minobe W, Abraham WT, Rizeq MN, Bohlmeyer TJ, Quaife RA, Roden RL, Dutcher DL, Robertson AD, Voelkel NF, Badesch DB, Groves BM, Gilbert EM, Bristow MR. Changes in gene expression in the intact human heart. Downregulation of alpha-myosin heavy chain in hypertrophied, failing ventricular myocardium. J Clin Invest 1997; 100:2315-24. [PMID: 9410910 PMCID: PMC508428 DOI: 10.1172/jci119770] [Citation(s) in RCA: 350] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Using quantitative RT-PCR in RNA from right ventricular (RV) endomyocardial biopsies from intact nonfailing hearts, and subjects with moderate RV failure from primary pulmonary hypertension (PPH) or idiopathic dilated cardiomyopathy (IDC), we measured expression of genes involved in regulation of contractility or hypertrophy. Gene expression was also assessed in LV (left ventricular) and RV free wall and RV endomyocardium of hearts from end-stage IDC subjects undergoing heart transplantation or from nonfailing donors. In intact failing hearts, downregulation of beta1-receptor mRNA and protein, upregulation of atrial natriuretic peptide mRNA expression, and increased myocyte diameter indicated similar degrees of failure and hypertrophy in the IDC and PPH phenotypes. The only molecular phenotypic difference between PPH and IDC RVs was upregulation of beta2-receptor gene expression in PPH but not IDC. The major new findings were that (a) both nonfailing intact and explanted human ventricular myocardium expressed substantial amounts of alpha-myosin heavy chain mRNA (alpha-MHC, 23-34% of total), and (b) in heart failure alpha-MHC was downregulated (by 67-84%) and beta-MHC gene expression was upregulated. We conclude that at the mRNA level nonfailing human heart expresses substantial alpha-MHC. In myocardial failure this alteration in gene expression of MHC isoforms, if translated into protein expression, would decrease myosin ATPase enzyme velocity and slow speed of contraction.
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Affiliation(s)
- B D Lowes
- Division of Cardiology, University of Colorado Health Sciences Center, Denver 80262, USA
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