51
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Affiliation(s)
- Bernard Brais
- Laboratory of Neurogenetics of Motion, Faculté de Médecine de l'Université de Montréal, Centre de Recherche cu CHUM, Hôpital Notre-Dame-CHUM, Montréal, Québec, Canada.
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52
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Morgan JE, Zammit PS. Direct effects of the pathogenic mutation on satellite cell function in muscular dystrophy. Exp Cell Res 2010; 316:3100-8. [DOI: 10.1016/j.yexcr.2010.05.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 05/03/2010] [Indexed: 12/14/2022]
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53
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Liu JL. Intracellular compartmentation of CTP synthase in Drosophila. J Genet Genomics 2010; 37:281-96. [PMID: 20513629 DOI: 10.1016/s1673-8527(09)60046-1] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 05/06/2010] [Indexed: 02/07/2023]
Abstract
Compartmentation is essential for the localization of biological processes within a eukaryotic cell. ATP synthase localizes to organelles such as mitochondria and chloroplasts. By contrast, little is known about the subcellular distribution of CTP synthase, the critical enzyme in the production of CTP, a high-energy molecule similar to ATP. Here I describe the identification of a novel intracellular structure containing CTP synthase, termed the cytoophidium, in Drosophila cells. I find that cytoophidia are present in all major cell types in the ovary and exist in a wide range of tissues such as brain, gut, trachea, testis, accessory gland, salivary gland and lymph gland. In addition, I find CTP synthase-containing cytoophidia in other fruit fly species. The observation of compartmentation of CTP synthase now permits a broad range of questions to be addressed concerning not only the structure and function of cytoophidia but also the organization and regulation of CTP synthesis.
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Affiliation(s)
- Ji-Long Liu
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3QX, United Kingdom.
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54
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Abstract
Alternative splicing of pre-mRNAs is a major contributor to proteomic diversity and to the control of gene expression in higher eukaryotic cells. For this reasons, alternative splicing is tightly regulated in different tissues and developmental stages and its disruption can lead to a wide range of human disorders. The aim of this review is to focus on the relevance of alternative splicing for muscle function and muscle disease. We begin by giving a brief overview of alternative splicing, muscle-specific gene expression and muscular dystrophy. Next, to illustrate these concepts we focus on two muscular dystrophy, myotonic muscular dystrophy and facioscapulohumeral muscular dystrophy, both associated to disruption of splicing regulation in muscle.
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Affiliation(s)
- Mariaelena Pistoni
- Division of Regenerative Medicine, San Raffaele Scientific Institute, Milan, Italy
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55
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Anthony K, Gallo JM. Aberrant RNA processing events in neurological disorders. Brain Res 2010; 1338:67-77. [DOI: 10.1016/j.brainres.2010.03.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 02/24/2010] [Accepted: 03/03/2010] [Indexed: 12/12/2022]
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56
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Apponi LH, Leung SW, Williams KR, Valentini SR, Corbett AH, Pavlath GK. Loss of nuclear poly(A)-binding protein 1 causes defects in myogenesis and mRNA biogenesis. Hum Mol Genet 2009; 19:1058-65. [PMID: 20035013 DOI: 10.1093/hmg/ddp569] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The nuclear poly(A)-binding protein 1 (PABPN1) is a ubiquitously expressed protein that plays a critical role in polyadenylation. Short expansions of the polyalanine tract in the N-terminus of PABPN1 lead to oculopharyngeal muscular dystrophy (OPMD), which is an adult onset disease characterized by eyelid drooping, difficulty in swallowing and weakness in the proximal limb muscles. Although significant data from in vitro biochemical assays define the function of PABPN1 in control of poly(A) tail length, little is known about the role of PABPN1 in mammalian cells. To assess the function of PABPN1 in mammalian cells and specifically in cells affected in OPMD, we examined the effects of PABPN1 depletion using siRNA in primary mouse myoblasts from extraocular, pharyngeal and limb muscles. PABPN1 knockdown significantly decreased cell proliferation and myoblast differentiation during myogenesis in vitro. At the molecular level, PABPN1 depletion in myoblasts led to a shortening of mRNA poly(A) tails, demonstrating the cellular function of PABPN1 in polyadenylation control in a mammalian cell. In addition, PABPN1 depletion caused nuclear accumulation of poly(A) RNA, revealing that PABPN1 is required for proper poly(A) RNA export from the nucleus. Together, these experiments demonstrate that PABPN1 plays an essential role in myoblast proliferation and differentiation, suggesting that it is required for muscle regeneration and maintenance in vivo.
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Affiliation(s)
- Luciano H Apponi
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
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57
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Abstract
Export of mRNA from the nucleus is a central process in eukaryotic gene expression that has been implicated in several human diseases. Much of our understanding of how an mRNA is transported to the cytoplasm is derived from studies using yeast and fly models. We present here different mechanisms by which aberrant nuclear retention of mRNA can cause human disease. Emerging evidence that implicates the mRNA export factor GLE1 in two lethal motor neuron disorders is discussed and we highlight surprising links to regulatory mechanisms that were first observed many years ago in yeast. These examples illustrate how model organisms have aided in our elucidation of complex human disorders through analysis of basic cellular processes.
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Affiliation(s)
- Jessica A Hurt
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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58
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Chartier A, Raz V, Sterrenburg E, Verrips CT, van der Maarel SM, Simonelig M. Prevention of oculopharyngeal muscular dystrophy by muscular expression of Llama single-chain intrabodies in vivo. Hum Mol Genet 2009; 18:1849-59. [DOI: 10.1093/hmg/ddp101] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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59
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Analysis of growth factor expression in affected and unaffected muscles of oculo-pharyngeal muscular dystrophy (OPMD) patients: A pilot study. Neuromuscul Disord 2009; 19:199-206. [DOI: 10.1016/j.nmd.2008.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/27/2008] [Accepted: 12/07/2008] [Indexed: 11/20/2022]
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60
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Kuo HC, Chen CM, Lee-Chen GJ, Hu FJ, Chu CC, Liou CW, Huang CC. Study of a Taiwanese family with oculopharyngeal muscular dystrophy. J Neurol Sci 2008; 278:21-4. [PMID: 19101703 DOI: 10.1016/j.jns.2008.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 10/14/2008] [Accepted: 11/04/2008] [Indexed: 11/18/2022]
Abstract
BACKGROUND Oculopharyngeal muscular dystrophy (OPMD) is a late onset autosomal dominant muscle disorder. OPMD is caused by a short trinucleotide repeat expansion encoding an expanded polyalanine tract in the polyadenylate binding-protein nuclear 1 (PABPN1) gene. We identified and characterized a PABPN1 mutation in a Taiwanese family with OPMD. METHODS The phenotypic and genotypic characteristics of all subjects were evaluated in a Taiwanese OPMD family. Genetic alterations in the PABPN1 gene were identified using PCR and DNA sequencing. RESULTS Ten subjects with OPMD (6 symptomatic and 4 asymptomatic) within the Taiwanese family carried a novel mutation in the PABPN1 gene. The normal (GCG)6(GCA)3GCG sequence was replaced by (GCG)6(GCA)(GCG)4(GCA)3GCG due to an insertion of (GCG)4GCA into the normal allele in the Taiwanese OPMD subjects. CONCLUSIONS In contrast to a single GCG expansion in most of OPMD patients in the literature, an insertion of (GCG)4GCA in the PABPN1 gene was found in the Taiwanese OPMD subjects. The identification of this mutation appears to support the molecular mechanism of unequal cross-over of two PABPN1 alleles.
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Affiliation(s)
- Hung-Chou Kuo
- Department of Neurology, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taipei, Taiwan.
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61
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The potential of intracellular antibodies for therapeutic targeting of protein-misfolding diseases. Trends Mol Med 2008; 14:373-80. [DOI: 10.1016/j.molmed.2008.07.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/04/2008] [Accepted: 07/04/2008] [Indexed: 12/25/2022]
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62
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Lukong KE, Chang KW, Khandjian EW, Richard S. RNA-binding proteins in human genetic disease. Trends Genet 2008; 24:416-25. [PMID: 18597886 DOI: 10.1016/j.tig.2008.05.004] [Citation(s) in RCA: 490] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 05/22/2008] [Accepted: 05/27/2008] [Indexed: 01/26/2023]
Abstract
RNA-binding proteins (RBPs) are key components in RNA metabolism, regulating the temporal, spatial and functional dynamics of RNAs. Altering the expression of RBPs has profound implications for cellular physiology, affecting RNA processes from pre-mRNA splicing to protein translation. Recent genetic and proteomic data and evidence from animal models reveal that RBPs are involved in many human diseases ranging from neurologic disorders to cancer. Here we review the emerging evidence showing the involvement of RBPs in many disease networks and conclude that defects in RNA metabolism caused by aberrations in RBPs might underlie a broader spectrum of complex human disorders.
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Affiliation(s)
- Kiven E Lukong
- Terry Fox Molecular Oncology Group, and the Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Department of Medicine, McGill University, Montréal, Québec H3T 1E2, Canada
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63
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Sackewitz M, von Einem S, Hause G, Wunderlich M, Schmid FX, Schwarz E. A folded and functional protein domain in an amyloid-like fibril. Protein Sci 2008; 17:1044-54. [PMID: 18424511 DOI: 10.1110/ps.073276308] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The effect of the polypeptide environment on polyalanine-induced fibril formation was investigated with amyloidogenic fragments from PAPBN1, a nuclear protein controlling polyadenylation. Mutation-caused extensions of the natural 10 alanine sequence up to maximally 17 alanines result in fibril formation of PABPN1 and the development of the disease oculopharyngeal muscular dystrophy (OPMD). We explored the influence of fibril formation on the structure and function of a one-domain protein linked to the fibril-forming part of PABPN1. The well-characterized, stably folded, one-domain protein, cold-shock protein CspB from Bacillus subtilis, was fused either to the C terminus of the entire N-terminal domain of PABPN1 or directly to peptides consisting of 10 or 17 alanine residues. The fusion protein between the N-terminal domain of PABPN1 and CspB formed fibrils in which the structure and activity of CspB were retained. In the fibrils formed by fusions in which the polyalanine sequence was directly linked to CspB, CspB was unfolded. These results indicate that the folded conformation and the function of a protein domain can be maintained in amyloid-like fibrils, and that the distance between this domain and the fibril plays an important role.
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Affiliation(s)
- Mirko Sackewitz
- Institut für Biochemie und Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany
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64
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Sirtuin inhibition protects from the polyalanine muscular dystrophy protein PABPN1. Hum Mol Genet 2008; 17:2108-17. [DOI: 10.1093/hmg/ddn109] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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65
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Davies JE, Sarkar S, Rubinsztein DC. Wild-type PABPN1 is anti-apoptotic and reduces toxicity of the oculopharyngeal muscular dystrophy mutation. Hum Mol Genet 2008; 17:1097-108. [DOI: 10.1093/hmg/ddm382] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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66
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Carré A, Castanet M, Sura-Trueba S, Szinnai G, Van Vliet G, Trochet D, Amiel J, Léger J, Czernichow P, Scotet V, Polak M. Polymorphic length of FOXE1 alanine stretch: evidence for genetic susceptibility to thyroid dysgenesis. Hum Genet 2007; 122:467-76. [PMID: 17717707 DOI: 10.1007/s00439-007-0420-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 08/03/2007] [Indexed: 01/31/2023]
Abstract
Familial cases of congenital hypothyroidism from thyroid dysgenesis (TD) (OMIM 218700) occur with a frequency 15-fold higher than by chance, FOXE1 is one of the candidate genes for this genetic predisposition and contains an alanine tract. Our purpose is to assess the influence of length of the alanine tract of FOXE1 on genetic susceptibility to TD. A case-control association study (based on 115 patients affected by TD and 129 controls genotyped by direct sequencing) and transmission disequilibrium testing (TDT) analyses were performed. The transcriptional activities of FOXE1 constructs containing 14 or 16 alanines were also studied. In the case-control association study, the 16/16 and 16/14 genotypes were inversely associated with TD (OR = 0.39, 95%CI = 0.22-0.68, P = 0.0005), strongly suggesting that the presence of 16 alanines in the tract protect against the occurrence of TD. This association was stronger in the subgroup of patients with ectopic thyroid (OR = 0.28, 95%CI = 0.13-0.58, P = 0.00015). The protection was confirmed by the TDT analysis performed in 39 trios (chi(2) = 4.3, P = 0.0374). Alternatively, the presence of the 14/14 genotype is associated with an increase risk of TD (OR = 2.59, 95%CI = 1.56-4.62, P = 0.0005). The expression studies showed that the transcriptional activities of FOXE1 with 16 alanines were significantly higher (1.55-fold) than FOXE1 containing 14 alanines (P < 0.003), while the nuclear localisation of the proteins was not affected. We conclude that FOXE1 through its alanine containing stretch modulates significantly the risk of TD occurrence, enhancing a mechanism linking an alanine containing transcription factor to disease.
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Affiliation(s)
- Aurore Carré
- Faculty of Medicine René Descartes, Paris V, Site Necker, Institut National de la Santé et de la Recherche Médicale U845 and Pediatric Endocrine Unit Assistance Publique-Hôpitaux de PARIS, Hôpital Necker Enfants-Malades, Paris, France
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