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Abstract
Atonal homologue 8 (atoh8) is a basic helix-loop-helix transcription factor expressed in a variety of embryonic tissues. While several studies have implicated atoh8 in various developmental pathways in other species, its role in zebrafish development remains uncertain. So far, no studies have dealt with an in-depth in situ analysis of the tissue distribution of atoh8 in embryonic zebrafish. We set out to pinpoint the exact location of atoh8 expression in a detailed spatio-temporal analysis in zebrafish during the first 24 h of development (hpf). To our surprise, we observed transcription from pre-segmentation stages in the paraxial mesoderm and during the segmentation stages in the somitic sclerotome and not—as previously reported—in the myotome. With progressing maturation of the somites, the restriction of atoh8 to the sclerotomal compartment became evident. Double in situ hybridisation with atoh8 and myoD revealed that both genes are expressed in the somites at coinciding developmental stages; however, their domains do not spatially overlap. A second domain of atoh8 expression emerged in the embryonic brain in the developing cerebellum and hindbrain. Here, we observed a specific expression pattern which was again in contrast to the previously published suggestion of atoh8 transcription in neural crest cells. Our findings point towards a possible role of atoh8 in sclerotome, cerebellum and hindbrain development. More importantly, the results of this expression analysis provide new insights into early sclerotome development in zebrafish—a field of research in developmental biology which has not received much attention so far.
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Furukawa Y, Miyaji Y, Kadoya A, Kamiya H, Chiba T, Hokkoku KI, Hatanaka Y, Imafuku I, Miyoshi K, Sonoo M. Determining C5, C6 and C7 myotomes through comparative analyses of clinical, MRI and EMG findings in cervical radiculopathy. Clin Neurophysiol Pract 2021; 6:88-92. [PMID: 33748550 PMCID: PMC7966958 DOI: 10.1016/j.cnp.2021.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 01/02/2021] [Accepted: 02/08/2021] [Indexed: 11/18/2022] Open
Abstract
Objective There are many myotome charts in the literature, but few studies have presented actual data to support their identification. We aimed to determine C5/C6/C7 myotomes based on clinical and EMG data of patients with cervical spondylotic radiculopathy (CSR) having a single-root lesion confirmed by MRI. Methods Medical Research Council (MRC) scores and EMG findings were retrospectively reviewed for patients enrolled from our EMG database. Results Enrolled were 25 patients (10 C5, 6 C6, and 9 C7 CSR). In C5 CSR, weakness or denervation potentials in EMG, or both, were observed in the deltoid (Del) and infraspinatus (Isp) muscles for all patients, and in the biceps brachii (BB) and brachioradialis (BR) muscles for 9/10 and 8/9 patients, respectively. In C6 CSR, weakness of the wrist extensor and/or denervation of the extensor carpi radialis longus (ECRL)/extensor carpi radialis brevis (ECRB), and those of the pronator teres (PT) were observed for all patients. Weakness was not observed for any other muscle in C6 CSR. Denervation potentials of ECRL were found in 5/8 and 3/5 patients with C5 and C6 CSR, respectively, whereas those of ECRB were found in 1/5, 6/6, and 2/5 patients with C5, C6 and C7 CSR, respectively. In C7 CSR, weakness/denervation of the triceps brachii (TB) and denervation potentials of the flexor carpi radialis (FCR) were observed for all patients. Denervation potentials in PT and weakness/denervation of the extensor digitorum (ED) were observed in 2/9 and 4/9 patients, respectively. Conclusion Suggested dominant myotomes are: C5 for the Del, Isp, BB, and BR, C5/6 for the ECRL, C6 > C7 for the ECRB and PT, and C7 for the TB and FCR. Significance The current study identified dominant myotomes that differ from the existing literature.
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Affiliation(s)
- Yuichi Furukawa
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
| | - Yosuke Miyaji
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama-shi, Kanagawa, Japan
| | - Akiko Kadoya
- Department of Neurology, Anti-aging and Vascular Medicine, National Defense Medical College, Namiki 3-2, Tokorozawa-shi, Saitama, Japan
| | - Hisao Kamiya
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
| | - Takashi Chiba
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
| | - Kei-ichi Hokkoku
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
| | - Yuki Hatanaka
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
| | - Ichiro Imafuku
- Department of Neurology, Yokohama Rosai Hospital, Kozukue 3211, Kohoku-ku, Yokohaya-shi, Kanagawa, Japan
| | - Kota Miyoshi
- Department of Orthopedics, Yokohama Rosai Hospital, Kozukue 3211, Kohoku-ku, Yokohaya-shi, Kanagawa, Japan
| | - Masahiro Sonoo
- Department of Neurology, Teikyo University School of Medicine, Kaga 2-11-1, Itabashi-ku, Tokyo, Japan
- Corresponding author.
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Wood WM, Otis C, Etemad S, Goldhamer DJ. Development and patterning of rib primordia are dependent on associated musculature. Dev Biol 2020; 468:133-145. [PMID: 32768399 DOI: 10.1016/j.ydbio.2020.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/20/2020] [Accepted: 07/29/2020] [Indexed: 01/29/2023]
Abstract
The importance of skeletal muscle for rib development and patterning in the mouse embryo has not been resolved, largely because different experimental approaches have yielded disparate results. In this study, we utilize both gene knockouts and muscle cell ablation approaches to re-visit the extent to which rib growth and patterning are dependent on developing musculature. Consistent with previous studies, we show that rib formation is highly dependent on the MYOD family of myogenic regulatory factors (MRFs), and demonstrate that the extent of rib formation is gene-, allele-, and dosage-dependent. In the absence of Myf5 and MyoD, one allele of Mrf4 is sufficient for extensive rib growth, although patterning is abnormal. Under conditions of limiting MRF dosage, MyoD is identified as a positive regulator of rib patterning, presumably due to improved intercostal muscle development. In contrast to previous muscle ablation studies, we show that diphtheria toxin subunit A (DTA)-mediated ablation of muscle progenitors or differentiated muscle, using MyoDiCre or HSA-Cre drivers, respectively, profoundly disrupts rib development. Further, a comparison of three independently derived Rosa26-based DTA knockin alleles demonstrates that the degree of rib perturbations in MyoDiCre/+/DTA embryos is markedly dependent on the DTA allele used, and may in part explain discrepancies with previous findings. The results support the conclusion that the extent and quality of rib formation is largely dependent on the dosage of Myf5 and Mrf4, and that both early myotome-sclerotome interactions, as well as later muscle-rib interactions, are important for proper rib growth and patterning.
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Affiliation(s)
- William M Wood
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT, USA
| | - Chelsea Otis
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT, USA
| | - Shervin Etemad
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT, USA
| | - David J Goldhamer
- Department of Molecular and Cell Biology, University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT, USA.
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Kahane N, Kalcheim C. Neural tube development depends on notochord-derived sonic hedgehog released into the sclerotome. Development 2020; 147:dev183996. [PMID: 32345743 PMCID: PMC7272346 DOI: 10.1242/dev.183996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 04/06/2020] [Indexed: 12/18/2022]
Abstract
Sonic hedgehog (Shh), produced in the notochord and floor plate, is necessary for both neural and mesodermal development. To reach the myotome, Shh has to traverse the sclerotome and a reduction of sclerotomal Shh affects myotome differentiation. By investigating loss and gain of Shh function, and floor-plate deletions, we report that sclerotomal Shh is also necessary for neural tube development. Reducing the amount of Shh in the sclerotome using a membrane-tethered hedgehog-interacting protein or Patched1, but not dominant active Patched, decreased the number of Olig2+ motoneuron progenitors and Hb9+ motoneurons without a significant effect on cell survival or proliferation. These effects were a specific and direct consequence of Shh reduction in the mesoderm. In addition, grafting notochords in a basal but not apical location, vis-à-vis the tube, profoundly affected motoneuron development, suggesting that initial ligand presentation occurs at the basal side of epithelia corresponding to the sclerotome-neural tube interface. Collectively, our results reveal that the sclerotome is a potential site of a Shh gradient that coordinates the development of mesodermal and neural progenitors.
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Affiliation(s)
- Nitza Kahane
- Department of Medical Neurobiology, Institute of Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Hebrew University of Jerusalem-Hadassah Medical School, Jerusalem 9112102, P.O. Box 12272, Israel
| | - Chaya Kalcheim
- Department of Medical Neurobiology, Institute of Medical Research Israel-Canada (IMRIC) and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Hebrew University of Jerusalem-Hadassah Medical School, Jerusalem 9112102, P.O. Box 12272, Israel
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Deries M, Thorsteinsdóttir S. Axial and limb muscle development: dialogue with the neighbourhood. Cell Mol Life Sci 2016; 73:4415-4431. [PMID: 27344602 DOI: 10.1007/s00018-016-2298-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/03/2016] [Accepted: 06/21/2016] [Indexed: 11/29/2022]
Abstract
Skeletal muscles are part of the musculoskeletal system which also includes nerves, tendons, connective tissue, bones and blood vessels. Here we review the development of axial and limb muscles in amniotes within the context of their surrounding tissues in vivo. We highlight the reciprocal dialogue mediated by signalling factors between cells of these adjacent tissues and developing muscles and also demonstrate its importance from the onset of muscle cell differentiation well into foetal development. Early embryonic tissues secrete factors which are important regulators of myogenesis. However, later muscle development relies on other tissue collaborators, such as developing nerves and connective tissue, which are in turn influenced by the developing muscles themselves. We conclude that skeletal muscle development in vivo is a compelling example of the importance of reciprocal interactions between developing tissues for the complete and coordinated development of a functional system.
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Affiliation(s)
- Marianne Deries
- Centro de Ecologia, Evolução e Alterações Ambientais, Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
| | - Sólveig Thorsteinsdóttir
- Centro de Ecologia, Evolução e Alterações Ambientais, Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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Pipalia TG, Koth J, Roy SD, Hammond CL, Kawakami K, Hughes SM. Cellular dynamics of regeneration reveals role of two distinct Pax7 stem cell populations in larval zebrafish muscle repair. Dis Model Mech 2016; 9:671-84. [PMID: 27149989 PMCID: PMC4920144 DOI: 10.1242/dmm.022251] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 04/27/2016] [Indexed: 12/25/2022] Open
Abstract
Heterogeneity of stem cells or their niches is likely to influence tissue regeneration. Here we reveal stem/precursor cell diversity during wound repair in larval zebrafish somitic body muscle using time-lapse 3D confocal microscopy on reporter lines. Skeletal muscle with incision wounds rapidly regenerates both slow and fast muscle fibre types. A swift immune response is followed by an increase in cells at the wound site, many of which express the muscle stem cell marker Pax7. Pax7(+) cells proliferate and then undergo terminal differentiation involving Myogenin accumulation and subsequent loss of Pax7 followed by elongation and fusion to repair fast muscle fibres. Analysis of pax7a and pax7b transgenic reporter fish reveals that cells expressing each of the duplicated pax7 genes are distinctly localised in uninjured larvae. Cells marked by pax7a only or by both pax7a and pax7b enter the wound rapidly and contribute to muscle wound repair, but each behaves differently. Low numbers of pax7a-only cells form nascent fibres. Time-lapse microscopy revealed that the more numerous pax7b-marked cells frequently fuse to pre-existing fibres, contributing more strongly than pax7a-only cells to repair of damaged fibres. pax7b-marked cells are more often present in rows of aligned cells that are observed to fuse into a single fibre, but more rarely contribute to nascent regenerated fibres. Ablation of a substantial portion of nitroreductase-expressing pax7b cells with metronidazole prior to wounding triggered rapid pax7a-only cell accumulation, but this neither inhibited nor augmented pax7a-only cell-derived myogenesis and thus altered the cellular repair dynamics during wound healing. Moreover, pax7a-only cells did not regenerate pax7b cells, suggesting a lineage distinction. We propose a modified founder cell and fusion-competent cell model in which pax7a-only cells initiate fibre formation and pax7b cells contribute to fibre growth. This newly discovered cellular complexity in muscle wound repair raises the possibility that distinct populations of myogenic cells contribute differentially to repair in other vertebrates.
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Affiliation(s)
- Tapan G Pipalia
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Jana Koth
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 9DS, UK
| | - Shukolpa D Roy
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Christina L Hammond
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, and Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Simon M Hughes
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
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Bell SW, Brown MJC, Hems TJ. Refinement of myotome values in the upper limb: Evidence from brachial plexus injuries. Surgeon 2015; 15:1-6. [PMID: 26409623 DOI: 10.1016/j.surge.2015.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/19/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE We reviewed patients with partial supraclavicular brachial plexus injuries in order to refine the myotome values of the upper limb. METHODS Forty-two patients with defined partial injuries to the supraclavicular brachial plexus were reviewed from a prospective database. The injuries patterns covered C5, C5-6, C5-7, C5-8, C7-T1 and C8-T1 roots. Upper plexus injuries were classified on the basis of surgical exploration and intraoperative stimulation and lower plexus injuries from MRI. RESULTS Flexor Carpi Radialis (FCR) was paralyzed in C5-7 injuries, in addition to paralysis of deltoid, supraspinatus, infraspinatus and biceps, when compared to C5-6 injuries. Complete paralysis of Flexor Digitorum Profundus (FDP) and Flexor Digitorum Superficialis (FDS) to all digits was identified in C7-T1 injuries. In C5-8 injuries weakness was noted in FDP of ulnar digits and intrinsics innervated by the ulnar nerve, while in C8-T1 injuries paralysis was noted in the FDP to the radial digits. All patients with C8-T1 injuries had paralysis of FDS and the thenar muscles. CONCLUSIONS In upper plexus injuries paralysis of FCR indicated involvement of C7 root in addition to C5 and C6 roots. The results provide new detail of innervation of muscles acting on the hand. Flexor muscles and intrinsic muscles of the thumb and radial fingers (median nerve) have an important contribution from T1, while for those acting on the ulnar digits (ulnar nerve) the main contribution is from C8 with some input from C7. T1 also gives consistent innervation to extensor pollicis longus. A revised myotome chart for the upper limb is proposed.
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Affiliation(s)
- S W Bell
- Scottish Brachial Plexus Injury Service, Victoria Infirmary, Langside Road, Glasgow G42 9TY, UK.
| | - M J C Brown
- Scottish Brachial Plexus Injury Service, Victoria Infirmary, Langside Road, Glasgow G42 9TY, UK
| | - T J Hems
- Scottish Brachial Plexus Injury Service, Victoria Infirmary, Langside Road, Glasgow G42 9TY, UK
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Musumeci G, Castrogiovanni P, Coleman R, Szychlinska MA, Salvatorelli L, Parenti R, Magro G, Imbesi R. Somitogenesis: From somite to skeletal muscle. Acta Histochem 2015; 117:313-28. [PMID: 25850375 DOI: 10.1016/j.acthis.2015.02.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/31/2015] [Accepted: 02/08/2015] [Indexed: 12/21/2022]
Abstract
Myogenesis is controlled by an elaborate system of extrinsic and intrinsic regulatory mechanisms in all development stages. The aim of this review is to provide an overview of the different stages of myogenesis and muscle differentiation in mammals, starting from somitogenesis and analysis of the different portions that constitute the mature somite. Particular attention was paid to regulatory genes, in addition to mesodermal stem cells, which represent the earliest elements of myogenesis. Finally, the crucial role of growth factors, molecules of vital importance in contractile regulation, hormones and their function in skeletal muscle differentiation, growth and metabolism, and the role played by central nervous system, are discussed.
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Affiliation(s)
- Giuseppe Musumeci
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy.
| | - Paola Castrogiovanni
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
| | - Raymond Coleman
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Marta Anna Szychlinska
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
| | - Lucia Salvatorelli
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rosalba Parenti
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, School of Medicine, University of Catania, Catania, Italy
| | - Gaetano Magro
- Department of Medical and Surgical Sciences and Advanced Technologies, G.F. Ingrassia, Azienda Ospedaliero-Universitaria "Policlinico-Vittorio Emanuele", Anatomic Pathology Section, University of Catania, Catania, Italy
| | - Rosa Imbesi
- Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, School of Medicine, University of Catania, Catania, Italy
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Windner SE, Doris RA, Ferguson CM, Nelson AC, Valentin G, Tan H, Oates AC, Wardle FC, Devoto SH. Tbx6, Mesp-b and Ripply1 regulate the onset of skeletal myogenesis in zebrafish. Development 2015; 142:1159-68. [PMID: 25725067 PMCID: PMC4360180 DOI: 10.1242/dev.113431] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 01/27/2015] [Indexed: 12/20/2022]
Abstract
During embryonic development, the paraxial mesoderm becomes segmented into somites, within which proliferative muscle progenitors and muscle fibers establish the skeletal musculature. Here, we demonstrate that a gene network previously implicated in somite boundary formation, involving the transcriptional regulators Tbx6, Mesp-b and Ripply1, also confers spatial and temporal regulation to skeletal myogenesis in zebrafish. We show that Tbx6 directly regulates mesp-b and ripply1 expression in vivo, and that the interactions within the regulatory network are largely conserved among vertebrates. Mesp-b is necessary and sufficient for the specification of a subpopulation of muscle progenitors, the central proportion of the Pax3(+)/Pax7(+) dermomyotome. Conditional ubiquitous expression indicates that Mesp-b acts by inhibiting myogenic differentiation and by inducing the dermomyotome marker meox1. By contrast, Ripply1 induces a negative-feedback loop by promoting Tbx6 protein degradation. Persistent Tbx6 expression in Ripply1 knockdown embryos correlates with a deficit in dermomyotome and myotome marker gene expression, suggesting that Ripply1 promotes myogenesis by terminating Tbx6-dependent inhibition of myogenic maturation. Together, our data suggest that Mesp-b is an intrinsic upstream regulator of skeletal muscle progenitors and that, in zebrafish, the genes regulating somite boundary formation also regulate the development of the dermomyotome in the anterior somite compartment.
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Affiliation(s)
| | - Rosemarie A Doris
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA
| | | | - Andrew C Nelson
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Guillaume Valentin
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
| | - Haihan Tan
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Andrew C Oates
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
| | - Fiona C Wardle
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Stephen H Devoto
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA
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Abstract
The muscle segments of fish have a folded shape, termed a chevron, which is thought to be optimal for the undulating body movements of swimming. However, the mechanism shaping the chevron during embryogenesis is not understood. Here, we used time-lapse microscopy of developing zebrafish embryos spanning the entire somitogenesis period to quantify the dynamics of chevron shape development. By comparing such time courses with the start of movements in wildtype zebrafish and analysing immobile mutants, we show that the previously implicated body movements do not play a role in chevron formation. Further, the monotonic increase of chevron angle along the anteroposterior axis revealed by our data constrains or rules out possible contributions by previously proposed mechanisms. In particular, we found that muscle pioneers are not required for chevron formation. We put forward a tension-and-resistance mechanism involving interactions between intra-segmental tension and segment boundaries. To evaluate this mechanism, we derived and analysed a mechanical model of a chain of contractile and resisting elements. The predictions of this model were verified by comparison with experimental data. Altogether, our results support the notion that a simple physical mechanism suffices to self-organize the observed spatiotemporal pattern in chevron formation.
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Affiliation(s)
- Fabian Rost
- Center for Information Services and High-Performance Computing, Technische Universität Dresden, 01062 Dresden, Germany
| | - Christina Eugster
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Christian Schröter
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Andrew C Oates
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Lutz Brusch
- Center for Information Services and High-Performance Computing, Technische Universität Dresden, 01062 Dresden, Germany
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Lippacher S, Mueller-Rossberg E, Reichel H, Nelitz M. Correction of malformative patellar instability in patients with nail-patella syndrome: a case report and review of the literature. Orthop Traumatol Surg Res 2013; 99:749-54. [PMID: 24029584 DOI: 10.1016/j.otsr.2013.03.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 03/24/2013] [Accepted: 03/27/2013] [Indexed: 02/02/2023]
Abstract
Nail-patella syndrome (NPS) or hereditary onycho-osteodysplasia is a relatively rare autosomal dominant disorder with the classic tetrad of fingernail abnormalities, hypoplastic patellae, radial head dislocation and iliac horns. The anatomic abnormalities in NPS often lead to subluxation or dislocation of the patellaeca causing knee instability and pain. Although most existing literature regarding the knee manifestation of this syndrome has focused on the clinically and radiological changes, only a few articles discussed the surgical treatment. This study reports the clinical, radiological and arthroscopical findings and a 24-month follow-up after operative stabilisation considering the underlying pathomorphology of malformative patellar instability in an 11-year-old girl. The findings of this study confirm the unique pathology of NPS with a synovial band preventing the engagement of the patella into the trochlear groove. NPS is a rare disorder and has to be considered in cases with untypical patella dislocation. The underlying pathology differs completely from patients with patellofemoral instability. The aim of orthopaedic surgery should be correction of the underlying pathology with resection of the synovial band and an additional realignment of the patella by recentering of the quadriceps muscle. Considering the underlying pathology good clinical results can be expected.
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Affiliation(s)
- S Lippacher
- Department of Orthopedic Surgery, University of Ulm, Germany.
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