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Mukherjee A, Nongthomba U. To RNA-binding and beyond: Emerging facets of the role of Rbfox proteins in development and disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023:e1813. [PMID: 37661850 DOI: 10.1002/wrna.1813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 09/05/2023]
Abstract
The RNA-binding Fox-1 homologue (Rbfox) proteins represent an ancient family of splicing factors, conserved through evolution. All members share an RNA recognition motif (RRM), and a particular affinity for the GCAUG signature in target RNA molecules. The role of Rbfox, as a splice factor, deciding the tissue-specific inclusion/exclusion of an exon, depending on its binding position on the flanking introns, is well known. Rbfox often acts in concert with other splicing factors, and forms splicing regulatory networks. Apart from this canonical role, recent studies show that Rbfox can also function as a transcription co-factor, and affects mRNA stability and translation. The repertoire of Rbfox targets is vast, including genes involved in the development of tissue lineages, such as neurogenesis, myogenesis, and erythropoeiesis, and molecular processes, including cytoskeletal dynamics, and calcium handling. A second layer of complexity is added by the fact that Rbfox expression itself is regulated by multiple mechanisms, and, in vertebrates, exhibits tissue-specific expression. The optimum dosage of Rbfox is critical, and its misexpression is etiological to various disease conditions. In this review, we discuss the contextual roles played by Rbfox as a tissue-specific regulator for the expression of many important genes with diverse functions, through the lens of the emerging data which highlights its involvement in many human diseases. Furthermore, we explore the mechanistic details provided by studies in model organisms, with emphasis on the work with Drosophila. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Turnover and Surveillance > Regulation of RNA Stability RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Amartya Mukherjee
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Upendra Nongthomba
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
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2
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Palo A, Patel SA, Sahoo B, Chowdary TK, Dixit M. FRG1 is a direct transcriptional regulator of nonsense-mediated mRNA decay genes. Genomics 2023; 115:110539. [PMID: 36521634 DOI: 10.1016/j.ygeno.2022.110539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 12/04/2022] [Accepted: 12/10/2022] [Indexed: 12/14/2022]
Abstract
FRG1 is the primary candidate gene for Fascioscapulohumeral Muscular Dystrophy. So far, its role has been reported in muscle development, vasculogenesis, angiogenesis, and tumorigenesis. Mechanistically studies suggest FRG1's role in RNA biogenesis which may have implications in multiple physiological processes and diseases, including tumorigenesis. Its probable role as hnRNP and association with NMD-related genes prompted us to look into FRG1's effect on NMD gene expression and the mechanism. Using microarray profiling in cell lines, we found that FRG1 altered the mRNA surveillance pathway and associated pathways, such as RNA transport and spliceosome machinery molecules. Multiple sequence alignment of core factors, namely, UPF1, UPF3B, and SMG1, showed conserved stretches of nucleotide sequence 'CTGGG'. Structural modeling followed by EMSA, ChIP-qPCR, and luciferase reporter assays showed 'CTGGG' as a FRG1 binding site. Analysis of the publicly available datasets showed that the expression of FRG1 correlates with NMD genes in different tissue types. We validated the effect of FRG1 on NMD gene transcription by qRT-PCR. Overall, FRG1 might be a transcriptional regulator of NMD genes.
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Affiliation(s)
- Ananya Palo
- National Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Saket Awadhesbhai Patel
- National Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Bibekananda Sahoo
- National Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Tirumala Kumar Chowdary
- National Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Manjusha Dixit
- National Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India; Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.
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3
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Shi DL, Grifone R. RNA-Binding Proteins in the Post-transcriptional Control of Skeletal Muscle Development, Regeneration and Disease. Front Cell Dev Biol 2021; 9:738978. [PMID: 34616743 PMCID: PMC8488162 DOI: 10.3389/fcell.2021.738978] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/31/2021] [Indexed: 12/21/2022] Open
Abstract
Embryonic myogenesis is a temporally and spatially regulated process that generates skeletal muscle of the trunk and limbs. During this process, mononucleated myoblasts derived from myogenic progenitor cells within the somites undergo proliferation, migration and differentiation to elongate and fuse into multinucleated functional myofibers. Skeletal muscle is the most abundant tissue of the body and has the remarkable ability to self-repair by re-activating the myogenic program in muscle stem cells, known as satellite cells. Post-transcriptional regulation of gene expression mediated by RNA-binding proteins is critically required for muscle development during embryogenesis and for muscle homeostasis in the adult. Differential subcellular localization and activity of RNA-binding proteins orchestrates target gene expression at multiple levels to regulate different steps of myogenesis. Dysfunctions of these post-transcriptional regulators impair muscle development and homeostasis, but also cause defects in motor neurons or the neuromuscular junction, resulting in muscle degeneration and neuromuscular disease. Many RNA-binding proteins, such as members of the muscle blind-like (MBNL) and CUG-BP and ETR-3-like factors (CELF) families, display both overlapping and distinct targets in muscle cells. Thus they function either cooperatively or antagonistically to coordinate myoblast proliferation and differentiation. Evidence is accumulating that the dynamic interplay of their regulatory activity may control the progression of myogenic program as well as stem cell quiescence and activation. Moreover, the role of RNA-binding proteins that regulate post-transcriptional modification in the myogenic program is far less understood as compared with transcription factors involved in myogenic specification and differentiation. Here we review past achievements and recent advances in understanding the functions of RNA-binding proteins during skeletal muscle development, regeneration and disease, with the aim to identify the fundamental questions that are still open for further investigations.
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Affiliation(s)
- De-Li Shi
- Affiliated Hospital of Guangdong Medical University, Zhanjiang, China.,Developmental Biology Laboratory, CNRS-UMR 7622, Institut de Biologie de Paris-Seine, Sorbonne University, Paris, France
| | - Raphaëlle Grifone
- Developmental Biology Laboratory, CNRS-UMR 7622, Institut de Biologie de Paris-Seine, Sorbonne University, Paris, France
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4
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Chen L, Tang F, Gao H, Zhang X, Li X, Xiao D. CAPN3: A muscle‑specific calpain with an important role in the pathogenesis of diseases (Review). Int J Mol Med 2021; 48:203. [PMID: 34549305 PMCID: PMC8480384 DOI: 10.3892/ijmm.2021.5036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/10/2021] [Indexed: 01/14/2023] Open
Abstract
Calpains are a family of Ca2+‑dependent cysteine proteases that participate in various cellular processes. Calpain 3 (CAPN3) is a classical calpain with unique N‑terminus and insertion sequence 1 and 2 domains that confer characteristics such as rapid autolysis, Ca2+‑independent activation and Na+ activation of the protease. CAPN3 is the only muscle‑specific calpain that has important roles in the promotion of calcium release from skeletal muscle fibers, calcium uptake of sarcoplasmic reticulum, muscle formation and muscle remodeling. Studies have indicated that recessive mutations in CAPN3 cause limb‑girdle muscular dystrophy (MD) type 2A and other types of MD; eosinophilic myositis, melanoma and epilepsy are also closely related to CAPN3. In the present review, the characteristics of CAPN3, its biological functions and roles in the pathogenesis of a number of disorders are discussed.
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Affiliation(s)
- Lin Chen
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Fajuan Tang
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Hu Gao
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Xiaoyan Zhang
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Xihong Li
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Dongqiong Xiao
- Department of Emergency Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
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5
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Alonso-Gonzalez A, Calaza M, Amigo J, González-Peñas J, Martínez-Regueiro R, Fernández-Prieto M, Parellada M, Arango C, Rodriguez-Fontenla C, Carracedo A. Exploring the biological role of postzygotic and germinal de novo mutations in ASD. Sci Rep 2021; 11:319. [PMID: 33431980 PMCID: PMC7801448 DOI: 10.1038/s41598-020-79412-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
De novo mutations (DNMs), including germinal and postzygotic mutations (PZMs), are a strong source of causality for Autism Spectrum Disorder (ASD). However, the biological processes involved behind them remain unexplored. Our aim was to detect DNMs (germinal and PZMs) in a Spanish ASD cohort (360 trios) and to explore their role across different biological hierarchies (gene, biological pathway, cell and brain areas) using bioinformatic approaches. For the majority of the analysis, a combined ASD cohort (N = 2171 trios) was created using previously published data by the Autism Sequencing Consortium (ASC). New plausible candidate genes for ASD such as FMR1 and NFIA were found. In addition, genes harboring PZMs were significantly enriched for miR-137 targets in comparison with germinal DNMs that were enriched in GO terms related to synaptic transmission. The expression pattern of genes with PZMs was restricted to early mid-fetal cortex. In contrast, the analysis of genes with germinal DNMs revealed a spatio-temporal window from early to mid-fetal development stages, with expression in the amygdala, cerebellum, cortex and striatum. These results provide evidence of the pathogenic role of PZMs and suggest the existence of distinct mechanisms between PZMs and germinal DNMs that are influencing ASD risk.
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Affiliation(s)
- A Alonso-Gonzalez
- Grupo de Medicina Xenómica, Fundación Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain
| | - M Calaza
- Grupo de Medicina Xenómica, Fundación Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain
| | - J Amigo
- Fundación Pública Galega de Medicina Xenómica (FPGMX), Centro de Investigación Biomédica en Red, Enfermedades Raras (CIBERER), Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - J González-Peñas
- Centro De Investigación Biomédica en Red de Salud Mental (CIBERSAM), Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, IiSGM, School of Medicine, Universidad Complutense, Madrid, Spain
| | - R Martínez-Regueiro
- Grupo de Medicina Xenómica, Fundación Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain
| | - M Fernández-Prieto
- Grupo de Medicina Xenómica, Fundación Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain
| | - M Parellada
- Centro De Investigación Biomédica en Red de Salud Mental (CIBERSAM), Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, IiSGM, School of Medicine, Universidad Complutense, Madrid, Spain
| | - C Arango
- Centro De Investigación Biomédica en Red de Salud Mental (CIBERSAM), Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, IiSGM, School of Medicine, Universidad Complutense, Madrid, Spain
| | - Cristina Rodriguez-Fontenla
- Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain.
| | - A Carracedo
- Grupo de Medicina Xenómica, Fundación Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Genomics and Bioinformatics Group, Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Av Barcelona 31, 15706, Santiago de Compostela, Spain.,Fundación Pública Galega de Medicina Xenómica (FPGMX), Centro de Investigación Biomédica en Red, Enfermedades Raras (CIBERER), Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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6
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Nikonova E, Kao SY, Ravichandran K, Wittner A, Spletter ML. Conserved functions of RNA-binding proteins in muscle. Int J Biochem Cell Biol 2019; 110:29-49. [PMID: 30818081 DOI: 10.1016/j.biocel.2019.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 02/21/2019] [Accepted: 02/23/2019] [Indexed: 12/13/2022]
Abstract
Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease. Although hundreds of genes predicted to bind RNA are expressed in muscles, many fewer have been functionally characterized. We present a cross-species view summarizing what is known about RNA-binding protein function in muscle, from worms and flies to zebrafish, mice and humans. In particular, we focus on alternative splicing regulated by the CELF, MBNL and RBFOX families of proteins. We discuss the systemic nature of diseases associated with loss of RNA-binding proteins in muscle, focusing on mis-regulation of CELF and MBNL in myotonic dystrophy. These examples illustrate the conservation of RNA-binding protein function and the marked utility of genetic model systems in understanding mechanisms of RNA regulation.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Keshika Ravichandran
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany; Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
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7
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Nakka K, Ghigna C, Gabellini D, Dilworth FJ. Diversification of the muscle proteome through alternative splicing. Skelet Muscle 2018; 8:8. [PMID: 29510724 PMCID: PMC5840707 DOI: 10.1186/s13395-018-0152-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
Background Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. Main body In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved “targeted” proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. Conclusions An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies. Electronic supplementary material The online version of this article (10.1186/s13395-018-0152-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kiran Nakka
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Claudia Ghigna
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy
| | - Davide Gabellini
- Unit of Gene Expression and Muscular Dystrophy, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, DIBIT2, 5A3-44, via Olgettina 58, 20132, Milan, Italy.
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada. .,Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, K1H 8L6, Canada.
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8
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Imbriano C, Molinari S. Alternative Splicing of Transcription Factors Genes in Muscle Physiology and Pathology. Genes (Basel) 2018; 9:genes9020107. [PMID: 29463057 PMCID: PMC5852603 DOI: 10.3390/genes9020107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/10/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle formation is a multi-step process that is governed by complex networks of transcription factors. The regulation of their functions is in turn multifaceted, including several mechanisms, among them alternative splicing (AS) plays a primary role. On the other hand, altered AS has a role in the pathogenesis of numerous muscular pathologies. Despite these premises, the causal role played by the altered splicing pattern of transcripts encoding myogenic transcription factors in neuromuscular diseases has been neglected so far. In this review, we systematically investigate what has been described about the AS patterns of transcription factors both in the physiology of the skeletal muscle formation process and in neuromuscular diseases, in the hope that this may be useful in re-evaluating the potential role of altered splicing of transcription factors in such diseases.
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Affiliation(s)
- Carol Imbriano
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
| | - Susanna Molinari
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
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9
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DeSimone AM, Pakula A, Lek A, Emerson CP. Facioscapulohumeral Muscular Dystrophy. Compr Physiol 2017; 7:1229-1279. [PMID: 28915324 DOI: 10.1002/cphy.c160039] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Facioscapulohumeral Muscular Dystrophy is a common form of muscular dystrophy that presents clinically with progressive weakness of the facial, scapular, and humeral muscles, with later involvement of the trunk and lower extremities. While typically inherited as autosomal dominant, facioscapulohumeral muscular dystrophy (FSHD) has a complex genetic and epigenetic etiology that has only recently been well described. The most prevalent form of the disease, FSHD1, is associated with the contraction of the D4Z4 microsatellite repeat array located on a permissive 4qA chromosome. D4Z4 contraction allows epigenetic derepression of the array, and possibly the surrounding 4q35 region, allowing misexpression of the toxic DUX4 transcription factor encoded within the terminal D4Z4 repeat in skeletal muscles. The less common form of the disease, FSHD2, results from haploinsufficiency of the SMCHD1 gene in individuals carrying a permissive 4qA allele, also leading to the derepression of DUX4, further supporting a central role for DUX4. How DUX4 misexpression contributes to FSHD muscle pathology is a major focus of current investigation. Misexpression of other genes at the 4q35 locus, including FRG1 and FAT1, and unlinked genes, such as SMCHD1, has also been implicated as disease modifiers, leading to several competing disease models. In this review, we describe recent advances in understanding the pathophysiology of FSHD, including the application of MRI as a research and diagnostic tool, the genetic and epigenetic disruptions associated with the disease, and the molecular basis of FSHD. We discuss how these advances are leading to the emergence of new approaches to enable development of FSHD therapeutics. © 2017 American Physiological Society. Compr Physiol 7:1229-1279, 2017.
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Affiliation(s)
- Alec M DeSimone
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Anna Pakula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA
| | - Angela Lek
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Charles P Emerson
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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10
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Faulty RNA splicing: consequences and therapeutic opportunities in brain and muscle disorders. Hum Genet 2017; 136:1215-1235. [DOI: 10.1007/s00439-017-1802-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
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11
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Conboy JG. Developmental regulation of RNA processing by Rbfox proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27748060 DOI: 10.1002/wrna.1398] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/17/2016] [Accepted: 08/27/2016] [Indexed: 12/15/2022]
Abstract
The Rbfox genes encode an ancient family of sequence-specific RNA binding proteins (RBPs) that are critical developmental regulators in multiple tissues including skeletal muscle, cardiac muscle, and brain. The hallmark of Rbfox proteins is a single high-affinity RRM domain, highly conserved from insects to humans, that binds preferentially to UGCAUG motifs at diverse regulatory sites in pre-mRNA introns, mRNA 3'UTRs, and pre-miRNAs hairpin structures. Versatile regulatory circuits operate on Rbfox pre-mRNA and mRNA to ensure proper expression of Rbfox1 protein isoforms, which then act on the broader transcriptome to regulate alternative splicing networks, mRNA stability and translation, and microRNA processing. Complex Rbfox expression is encoded in large genes encompassing multiple promoters and alternative splicing options that govern spatiotemporal expression of structurally distinct and tissue-specific protein isoforms with different classes of RNA targets. Nuclear Rbfox1 is a candidate master regulator that binds intronic UGCAUG elements to impact splicing efficiency of target alternative exons, many in transcripts for other splicing regulators. Tissue-specificity of Rbfox-mediated alternative splicing is executed by combinatorial regulation through the integrated activity of Rbfox proteins and synergistic or antagonistic splicing factors. Studies in animal models show that Rbfox1-related genes are critical for diverse developmental processes including germ cell differentiation and memory in Drosophila, neuronal migration and function in mouse brain, myoblast fusion and skeletal muscle function, and normal heart function. Finally, genetic and biochemical evidence suggest that aberrations in Rbfox-regulated circuitry are risk factors for multiple human disorders, especially neurodevelopmental disorders including epilepsy and autism, and cardiac hypertrophy. WIREs RNA 2017, 8:e1398. doi: 10.1002/wrna.1398 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- John G Conboy
- Biological Systems and Engineering Division Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA
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12
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An eccentric calpain, CAPN3/p94/calpain-3. Biochimie 2016; 122:169-87. [DOI: 10.1016/j.biochi.2015.09.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/07/2015] [Indexed: 01/09/2023]
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13
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Ansseau E, Eidahl JO, Lancelot C, Tassin A, Matteotti C, Yip C, Liu J, Leroy B, Hubeau C, Gerbaux C, Cloet S, Wauters A, Zorbo S, Meyer P, Pirson I, Laoudj-Chenivesse D, Wattiez R, Harper SQ, Belayew A, Coppée F. Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation. PLoS One 2016; 11:e0146893. [PMID: 26816005 PMCID: PMC4729438 DOI: 10.1371/journal.pone.0146893] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 12/24/2015] [Indexed: 12/26/2022] Open
Abstract
Hundreds of double homeobox (DUX) genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD). In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain) and DUX1 (which is limited to the double homeodomain). Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay) the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay) as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs). Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs were recently shown to exit the nucleus via a novel mechanism of nuclear envelope budding. Following DUX4 or DUX4c overexpression in muscle cell cultures, we observed their association with similar nuclear buds. In conclusion, our study demonstrated unexpected interactions of DUX4/4c with cytoplasmic proteins playing major roles during muscle differentiation. Further investigations are on-going to evaluate whether these interactions play roles during muscle regeneration as previously suggested for DUX4c.
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Affiliation(s)
- Eugénie Ansseau
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Jocelyn O. Eidahl
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Céline Lancelot
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Alexandra Tassin
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Christel Matteotti
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Cassandre Yip
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Jian Liu
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Baptiste Leroy
- Laboratory of Proteomic and Microbiology, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Céline Hubeau
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Cécile Gerbaux
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Samuel Cloet
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Armelle Wauters
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Sabrina Zorbo
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Pierre Meyer
- Pediatric Department, CHRU Montpellier, Montpellier, France
| | - Isabelle Pirson
- I.R.I.B.H.M., Free University of Brussels, Brussels, Belgium
| | | | - Ruddy Wattiez
- Laboratory of Proteomic and Microbiology, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Scott Q. Harper
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
- Department of Pediatrics, Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Alexandra Belayew
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Frédérique Coppée
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
- * E-mail:
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Feeney SJ, McGrath MJ, Sriratana A, Gehrig SM, Lynch GS, D’Arcy CE, Price JT, McLean CA, Tupler R, Mitchell CA. FHL1 reduces dystrophy in transgenic mice overexpressing FSHD muscular dystrophy region gene 1 (FRG1). PLoS One 2015; 10:e0117665. [PMID: 25695429 PMCID: PMC4335040 DOI: 10.1371/journal.pone.0117665] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/29/2014] [Indexed: 01/01/2023] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease with no effective treatment. The genetic cause of FSHD is complex and the primary pathogenic insult underlying the muscle disease is unknown. Several disease candidate genes have been proposed including DUX4 and FRG1. Expression analysis studies of FSHD report the deregulation of genes which mediate myoblast differentiation and fusion. Transgenic mice overexpressing FRG1 recapitulate the FSHD muscular dystrophy phenotype. Our current study selectively examines how increased expression of FRG1 may contribute to myoblast differentiation defects. We generated stable C2C12 cell lines overexpressing FRG1, which exhibited a myoblast fusion defect upon differentiation. To determine if myoblast fusion defects contribute to the FRG1 mouse dystrophic phenotype, this strain was crossed with skeletal muscle specific FHL1-transgenic mice. We previously reported that FHL1 promotes myoblast fusion in vitro and FHL1-transgenic mice develop skeletal muscle hypertrophy. In the current study, FRG1 mice overexpressing FHL1 showed an improvement in the dystrophic phenotype, including a reduced spinal kyphosis, increased muscle mass and myofiber size, and decreased muscle fibrosis. FHL1 expression in FRG1 mice, did not alter satellite cell number or activation, but enhanced myoblast fusion. Primary myoblasts isolated from FRG1 mice showed a myoblast fusion defect that was rescued by FHL1 expression. Therefore, increased FRG1 expression may contribute to a muscular dystrophy phenotype resembling FSHD by impairing myoblast fusion, a defect that can be rescued by enhanced myoblast fusion via expression of FHL1.
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Affiliation(s)
- Sandra J. Feeney
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Meagan J. McGrath
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Absorn Sriratana
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Stefan M. Gehrig
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria, 3010, Australia
| | - Gordon S. Lynch
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria, 3010, Australia
| | - Colleen E. D’Arcy
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - John T. Price
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Catriona A. McLean
- Department of Anatomical Pathology, Alfred Hospital, Prahran, Victoria, 3004, Australia
- Department of Medicine, Central Clinical School, Monash University, Clayton, VIC, 3800, Australia
| | - Rossella Tupler
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA, 01655, United States of America
- Dipartimento di Scienze della Vita, Universita di Modena e Reggio Emilia, 41125, Modena, Italy
| | - Christina A. Mitchell
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
- * E-mail:
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Pedrotti S, Giudice J, Dagnino-Acosta A, Knoblauch M, Singh RK, Hanna A, Mo Q, Hicks J, Hamilton S, Cooper TA. The RNA-binding protein Rbfox1 regulates splicing required for skeletal muscle structure and function. Hum Mol Genet 2015; 24:2360-74. [PMID: 25575511 DOI: 10.1093/hmg/ddv003] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Rbfox family of RNA-binding proteins is highly conserved with established roles in alternative splicing (AS) regulation. High-throughput studies aimed at understanding transcriptome remodeling have revealed skeletal muscle as displaying one of the largest number of AS events. This finding is consistent with requirements for tissue-specific protein isoforms needed to sustain muscle-specific functions. Rbfox1 is abundant in vertebrate brain, heart and skeletal muscle. Genome-wide genetic approaches have linked the Rbfox1 gene to autism, and a brain-specific knockout mouse revealed a critical role for this splicing regulator in neuronal function. Moreover, a Caenorhabditis elegans Rbfox1 homolog regulates muscle-specific splicing. To determine the role of Rbfox1 in muscle function, we developed a conditional knockout mouse model to specifically delete Rbfox1 in adult tissue. We show that Rbfox1 is required for muscle function but a >70% loss of Rbfox1 in satellite cells does not disrupt muscle regeneration. Deep sequencing identified aberrant splicing of multiple genes including those encoding myofibrillar and cytoskeletal proteins, and proteins that regulate calcium handling. Ultrastructure analysis of Rbfox1(-/-) muscle by electron microscopy revealed abundant tubular aggregates. Immunostaining showed mislocalization of the sarcoplasmic reticulum proteins Serca1 and Ryr1 in a pattern indicative of colocalization with the tubular aggregates. Consistent with mislocalization of Serca1 and Ryr1, calcium handling was drastically altered in Rbfox1(-/-) muscle. Moreover, muscle function was significantly impaired in Rbfox1(-/-) muscle as indicated by decreased force generation. These results demonstrate that Rbfox1 regulates a network of AS events required to maintain multiple aspects of muscle physiology.
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Affiliation(s)
| | | | | | | | | | - Amy Hanna
- Department of Molecular Physiology and Biophysics
| | - Qianxing Mo
- Dan L. Duncan Cancer Center, Department of Medicine
| | - John Hicks
- Department of Pathology and Immunology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA and Texas Children's Hospital, Houston, TX 77030, USA
| | | | - Thomas A Cooper
- Department of Pathology and Immunology, Department of Molecular and Cellular Biology, Department of Molecular Physiology and Biophysics,
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Thijssen PE, Balog J, Yao Z, Pham TP, Tawil R, Tapscott SJ, Van der Maarel SM. DUX4 promotes transcription of FRG2 by directly activating its promoter in facioscapulohumeral muscular dystrophy. Skelet Muscle 2014; 4:19. [PMID: 25789155 PMCID: PMC4364343 DOI: 10.1186/2044-5040-4-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 10/13/2014] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The most common form of facioscapulohumeral muscular dystrophy (FSHD) is caused by a genetic contraction of the polymorphic D4Z4 macrosatellite repeat array in the subtelomeric region of chromosome 4q. In some studies, genes centromeric to the D4Z4 repeat array have been reported to be over-expressed in FSHD, including FRG1 and FRG2, presumably due to decreased long-distance repression by the shorter array through a mechanism similar to position-effect variegation. Differential regulation of FRG1 in FSHD has never been unequivocally proven, however, FRG2 has been reproducibly shown to be induced in primary FSHD-derived muscle cells when differentiated in vitro. The molecular function of FRG2 and a possible contribution to FSHD pathology remain unclear. Recent evidence has identified the mis-expression of DUX4, located within the D4Z4 repeat unit, in skeletal muscle as the cause of FSHD. DUX4 is a double homeobox transcription factor that has been shown to be toxic when expressed in muscle cells. METHODS We used a combination of expression analysis by qRT/PCR and RNA sequencing to determine the transcriptional activation of FRG2 and DUX4. We examined this in both differentiating control and FSHD derived muscle cell cultures or DUX4 transduced control cell lines. Next, we used ChIP-seq analysis and luciferase reporter assays to determine the potential DUX4 transactivation effect on the FRG2 promoter. RESULTS We show that DUX4 directly activates the expression of FRG2. Increased expression of FRG2 was observed following expression of DUX4 in myoblasts and fibroblasts derived from control individuals. Moreover, we identified DUX4 binding sites at the FRG2 promoter by chromatin immunoprecipitation followed by deep sequencing and confirmed the direct regulation of DUX4 on the FRG2 promoter by luciferase reporter assays. Activation of luciferase was dependent on both DUX4 expression and the presence of the DUX4 DNA binding motifs in the FRG2 promoter. CONCLUSION We show that the FSHD-specific upregulation of FRG2 is a direct consequence of the activity of DUX4 protein rather than representing a regional de-repression secondary to fewer D4Z4 repeats.
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Affiliation(s)
- Peter E Thijssen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Judit Balog
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Zizhen Yao
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle WA 98109, USA
| | - Tan Phát Pham
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
| | - Rabi Tawil
- Neuromuscular Disease Unit, Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Stephen J Tapscott
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle WA 98109, USA
| | - Silvère M Van der Maarel
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, Leiden 2333 ZA, The Netherlands
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Ferri G, Huichalaf CH, Caccia R, Gabellini D. Direct interplay between two candidate genes in FSHD muscular dystrophy. Hum Mol Genet 2014; 24:1256-66. [PMID: 25326393 PMCID: PMC4321439 DOI: 10.1093/hmg/ddu536] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common neuromuscular disorders. The major form of the disease (FSHD1) is linked to decrease in copy number of a 3.3-kb tandem repeated macrosatellite (D4Z4), located on chromosome 4q35. D4Z4 deletion alters chromatin structure of the locus leading to aberrant expression of nearby 4q35 genes. Given the high variability in disease onset and progression, multiple factors could contribute to the pathogenesis of FSHD. Among the FSHD candidate genes are double homeobox 4 (DUX4), encoded by the most telomeric D4Z4 unit, and FSHD region gene 1 (FRG1). DUX4 is a sequence-specific transcription factor. Here, we located putative DUX4 binding sites in the human FRG1 genomic area and we show specific DUX4 association to these regions. We found also that ectopically expressed DUX4 up-regulates the endogenous human FRG1 gene in healthy muscle cells, while DUX4 knockdown leads to a decrease in FRG1 expression in FSHD muscle cells. Moreover, DUX4 binds directly and specifically to its binding site located in the human FRG1 gene and transactivates constructs containing FRG1 genomic regions. Intriguingly, the mouse Frg1 genomic area lacks DUX4 binding sites and DUX4 is unable to activate the endogenous mouse Frg1 gene providing a possible explanation for the lack of muscle phenotype in DUX4 transgenic mice. Altogether, our results demonstrate that FRG1 is a direct DUX4 transcriptional target uncovering a novel regulatory circuit contributing to FSHD.
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Affiliation(s)
- Giulia Ferri
- Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Dulbecco Telethon Institute at San Raffaele Scientific Institute, DIBIT2, 5A3, Via Olgettina 58, 20132 Milan, Italy Università Vita-Salute San Raffaele, Milan, Italy
| | - Claudia H Huichalaf
- Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Dulbecco Telethon Institute at San Raffaele Scientific Institute, DIBIT2, 5A3, Via Olgettina 58, 20132 Milan, Italy Università Vita-Salute San Raffaele, Milan, Italy
| | - Roberta Caccia
- Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Dulbecco Telethon Institute at San Raffaele Scientific Institute, DIBIT2, 5A3, Via Olgettina 58, 20132 Milan, Italy
| | - Davide Gabellini
- Division of Regenerative Medicine, Stem Cells, and Gene Therapy, Dulbecco Telethon Institute at San Raffaele Scientific Institute, DIBIT2, 5A3, Via Olgettina 58, 20132 Milan, Italy
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Rbfox3 controls the biogenesis of a subset of microRNAs. Nat Struct Mol Biol 2014; 21:901-10. [PMID: 25240799 PMCID: PMC4189996 DOI: 10.1038/nsmb.2892] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/23/2014] [Indexed: 12/21/2022]
Abstract
RNA-binding proteins (RBPs) regulate numerous aspects of gene expression; thus, identification of their endogenous targets is important for understanding their cellular functions. Here we identified transcriptome-wide targets of Rbfox3 in neuronally differentiated P19 cells and mouse brain by using photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP). Although Rbfox3 is known to regulate pre-mRNA splicing through binding the UGCAUG motif, PAR-CLIP analysis revealed diverse Rbfox3 targets including primary microRNAs (pri-miRNAs) that lack the UGCAUG motif. Induced expression and depletion of Rbfox3 led to changes in the expression levels of a subset of PAR-CLIP-detected miRNAs. In vitro analyses revealed that Rbfox3 functions as a positive and a negative regulator at the stage of pri-miRNA processing to precursor miRNA (pre-miRNA). Rbfox3 binds directly to pri-miRNAs and regulates the recruitment of the microprocessor complex to pri-miRNAs. Our study proposes a new function for Rbfox3 in miRNA biogenesis.
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RBFOX1 cooperates with MBNL1 to control splicing in muscle, including events altered in myotonic dystrophy type 1. PLoS One 2014; 9:e107324. [PMID: 25211016 PMCID: PMC4161394 DOI: 10.1371/journal.pone.0107324] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/12/2014] [Indexed: 12/22/2022] Open
Abstract
With the goal of identifying splicing alterations in myotonic dystrophy 1 (DM1) tissues that may yield insights into targets or mechanisms, we have surveyed mis-splicing events in three systems using a RT-PCR screening and validation platform. First, a transgenic mouse model expressing CUG-repeats identified splicing alterations shared with other mouse models of DM1. Second, using cell cultures from human embryonic muscle, we noted that DM1-associated splicing alterations were significantly enriched in cytoskeleton (e.g. SORBS1, TACC2, TTN, ACTN1 and DMD) and channel (e.g. KCND3 and TRPM4) genes. Third, of the splicing alterations occurring in adult DM1 tissues, one produced a dominant negative variant of the splicing regulator RBFOX1. Notably, half of the splicing events controlled by MBNL1 were co-regulated by RBFOX1, and several events in this category were mis-spliced in DM1 tissues. Our results suggest that reduced RBFOX1 activity in DM1 tissues may amplify several of the splicing alterations caused by the deficiency in MBNL1.
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20
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Singh RK, Xia Z, Bland CS, Kalsotra A, Scavuzzo MA, Curk T, Ule J, Li W, Cooper TA. Rbfox2-coordinated alternative splicing of Mef2d and Rock2 controls myoblast fusion during myogenesis. Mol Cell 2014; 55:592-603. [PMID: 25087874 DOI: 10.1016/j.molcel.2014.06.035] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 05/15/2014] [Accepted: 06/27/2014] [Indexed: 12/29/2022]
Abstract
Alternative splicing plays important regulatory roles during periods of physiological change. During development, a large number of genes coordinately express protein isoform transitions regulated by alternative splicing; however, the mechanisms that coordinate splicing and the functional integration of the resultant tissue-specific protein isoforms are typically unknown. Here we show that the conserved Rbfox2 RNA binding protein regulates 30% of the splicing transitions observed during myogenesis and is required for the specific step of myoblast fusion. Integration of Rbfox2-dependent splicing outcomes from RNA-seq with Rbfox2 iCLIP data identified Mef2d and Rock2 as Rbfox2 splicing targets. Restored activities of Mef2d and Rock2 rescued myoblast fusion in Rbfox2-depleted cultures, demonstrating functional cooperation of protein isoforms generated by coordinated alterative splicing. The results demonstrate that coordinated alternative splicing by a single RNA binding protein modulates transcription (Mef2d) and cell signaling (Rock2) programs to drive tissue-specific functions (cell fusion) to promote a developmental transition.
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Affiliation(s)
- Ravi K Singh
- Departments of Pathology and Immunology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Zheng Xia
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA.,Departments of Dan L. Duncan Cancer Center, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Christopher S Bland
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Auinash Kalsotra
- Departments of Pathology and Immunology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Marissa A Scavuzzo
- Departments of Pathology and Immunology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Tomaz Curk
- University of Ljubljana, Faculty of Computer and Information Science, Trẑaŝka cesta 25, SI-1000 Ljubljana
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Wei Li
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA.,Departments of Dan L. Duncan Cancer Center, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
| | - Thomas A Cooper
- Departments of Pathology and Immunology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA.,Departments of Molecular and Cellular Biology, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA.,Departments of Molecular Physiology and Biophysics, Baylor College of Medicine, Medicine, Houston, Texas 77030, USA
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Orchestration of neurodevelopmental programs by RBFOX1: implications for autism spectrum disorder. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 113:251-67. [PMID: 24290388 DOI: 10.1016/b978-0-12-418700-9.00008-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Neurodevelopmental and neuropsychiatric disorders result from complex interactions between critical genetic factors and as-yet-unknown environmental components. To gain clinical insight, it is critical to develop a comprehensive understanding of these genetic components. RBFOX1, an RNA splicing factor, regulates expression of large genetic networks during early neuronal development, and haploinsufficiency causes severe neurodevelopmental phenotypes including autism spectrum disorder (ASD), intellectual disability, and epilepsy. Genomic testing in individuals and large patient cohorts has identified phenotypically similar cases possessing copy number variations in RBFOX1, implicating the gene as an important cause of neurodevelopmental disease. However, a significant proportion of the observed structural variation is inherited from phenotypically normal individuals, raising questions regarding overall pathogenicity of variation at the RBFOX1 locus. In this chapter, we discuss the molecular, cellular, and clinical evidence supporting the role of RBFOX1 in neurodevelopment and present a comprehensive model for the contribution of structural variation in RBFOX1 to ASD.
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Pimentel H, Parra M, Gee S, Ghanem D, An X, Li J, Mohandas N, Pachter L, Conboy JG. A dynamic alternative splicing program regulates gene expression during terminal erythropoiesis. Nucleic Acids Res 2014; 42:4031-42. [PMID: 24442673 PMCID: PMC3973340 DOI: 10.1093/nar/gkt1388] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alternative pre-messenger RNA splicing remodels the human transcriptome in a spatiotemporal manner during normal development and differentiation. Here we explored the landscape of transcript diversity in the erythroid lineage by RNA-seq analysis of five highly purified populations of morphologically distinct human erythroblasts, representing the last four cell divisions before enucleation. In this unique differentiation system, we found evidence of an extensive and dynamic alternative splicing program encompassing genes with many diverse functions. Alternative splicing was particularly enriched in genes controlling cell cycle, organelle organization, chromatin function and RNA processing. Many alternative exons exhibited differentiation-associated switches in splicing efficiency, mostly in late-stage polychromatophilic and orthochromatophilic erythroblasts, in concert with extensive cellular remodeling that precedes enucleation. A subset of alternative splicing switches introduces premature translation termination codons into selected transcripts in a differentiation stage-specific manner, supporting the hypothesis that alternative splicing-coupled nonsense-mediated decay contributes to regulation of erythroid-expressed genes as a novel part of the overall differentiation program. We conclude that a highly dynamic alternative splicing program in terminally differentiating erythroblasts plays a major role in regulating gene expression to ensure synthesis of appropriate proteome at each stage as the cells remodel in preparation for production of mature red cells.
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Affiliation(s)
- Harold Pimentel
- Department of Computer Science, University of California, Berkeley, CA 94720, USA, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA, Red Cell Physiology Laboratory, New York Blood Center, New York, NY 10065, USA, Department of Mathematics, University of California, Berkeley, CA 94720, USA and Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
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23
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Dmitriev P, Kairov U, Robert T, Barat A, Lazar V, Carnac G, Laoudj-Chenivesse D, Vassetzky YS. Cancer-related genes in the transcription signature of facioscapulohumeral dystrophy myoblasts and myotubes. J Cell Mol Med 2013; 18:208-17. [PMID: 24341522 PMCID: PMC3930408 DOI: 10.1111/jcmm.12182] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 10/08/2013] [Indexed: 01/23/2023] Open
Abstract
Muscular dystrophy is a condition potentially predisposing for cancer; however, currently, only Myotonic dystrophy patients are known to have a higher risk of cancer. Here, we have searched for a link between facioscapulohumeral dystrophy (FSHD) and cancer by comparing published transcriptome signatures of FSHD and various malignant tumours and have found a significant enrichment of cancer-related genes among the genes differentially expressed in FSHD. The analysis has shown that gene expression profiles of FSHD myoblasts and myotubes resemble that of Ewing's sarcoma more than that of other cancer types tested. This is the first study demonstrating a similarity between FSHD and cancer cell expression profiles, a finding that might indicate the existence of a common step in the pathogenesis of these two diseases.
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Affiliation(s)
- Petr Dmitriev
- UMR8126, Université Paris-Sud 11, CNRS, Institut de cancérologie Gustave Roussy, Villejuif, France; INSERM U1046, Université Montpellier I, Montpellier, France
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González-Navarro FF, Belanche-Muñoz LA, Silva-Colón KA. Effective classification and gene expression profiling for the Facioscapulohumeral Muscular Dystrophy. PLoS One 2013; 8:e82071. [PMID: 24349187 PMCID: PMC3862578 DOI: 10.1371/journal.pone.0082071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 10/21/2013] [Indexed: 12/03/2022] Open
Abstract
The Facioscapulohumeral Muscular Dystrophy (FSHD) is an autosomal dominant neuromuscular disorder whose incidence is estimated in about one in 400,000 to one in 20,000. No effective therapeutic strategies are known to halt progression or reverse muscle weakness and atrophy. It is known that the FSHD is caused by modifications located within a D4ZA repeat array in the chromosome 4q, while recent advances have linked these modifications to the DUX4 gene. Unfortunately, the complete mechanisms responsible for the molecular pathogenesis and progressive muscle weakness still remain unknown. Although there are many studies addressing cancer databases from a machine learning perspective, there is no such precedent in the analysis of the FSHD. This study aims to fill this gap by analyzing two specific FSHD databases. A feature selection algorithm is used as the main engine to select genes promoting the highest possible classification capacity. The combination of feature selection and classification aims at obtaining simple models (in terms of very low numbers of genes) capable of good generalization, that may be associated with the disease. We show that the reported method is highly efficient in finding genes to discern between healthy cases (not affected by the FSHD) and FSHD cases, allowing the discovery of very parsimonious models that yield negligible repeated cross-validation error. These models in turn give rise to very simple decision procedures in the form of a decision tree. Current biological evidence regarding these genes shows that they are linked to skeletal muscle processes concerning specific human conditions.
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Affiliation(s)
| | | | - Karen A. Silva-Colón
- Instituto de Ingeniería, Universidad Autónoma de Baja California, Mexicali, México
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Sancisi V, Germinario E, Esposito A, Morini E, Peron S, Moggio M, Tomelleri G, Danieli-Betto D, Tupler R. Altered Tnnt3 characterizes selective weakness of fast fibers in mice overexpressing FSHD region gene 1 (FRG1). Am J Physiol Regul Integr Comp Physiol 2013; 306:R124-37. [PMID: 24305066 DOI: 10.1152/ajpregu.00379.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD), a common hereditary myopathy, is characterized by atrophy and weakness of selective muscle groups. FSHD is considered an autosomal dominant disease with incomplete penetrance and unpredictable variability of clinical expression within families. Mice overexpressing FRG1 (FSHD region gene 1), a candidate gene for this disease, develop a progressive myopathy with features of the human disorder. Here, we show that in FRG1-overexpressing mice, fast muscles, which are the most affected by the dystrophic process, display anomalous fast skeletal troponin T (fTnT) isoform, resulting from the aberrant splicing of the Tnnt3 mRNA that precedes the appearance of dystrophic signs. We determine that muscles of FRG1 mice develop less strength due to impaired contractile properties of fast-twitch fibers associated with an anomalous MyHC-actin ratio and a reduced sensitivity to Ca(2+). We demonstrate that the decrease of Ca(2+) sensitivity of fast-twitch fibers depends on the anomalous troponin complex and can be rescued by the substitution with the wild-type proteins. Finally, we find that the presence of aberrant splicing isoforms of TNNT3 characterizes dystrophic muscles in FSHD patients. Collectively, our results suggest that anomalous TNNT3 profile correlates with the muscle impairment in both humans and mice. On the basis of these results, we propose that aberrant fTnT represents a biological marker of muscle phenotype severity and disease progression.
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Affiliation(s)
- Valentina Sancisi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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26
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Lovci MT, Ghanem D, Marr H, Arnold J, Gee S, Parra M, Liang TY, Stark TJ, Gehman LT, Hoon S, Massirer KB, Pratt GA, Black DL, Gray JW, Conboy JG, Yeo GW. Rbfox proteins regulate alternative mRNA splicing through evolutionarily conserved RNA bridges. Nat Struct Mol Biol 2013; 20:1434-42. [PMID: 24213538 DOI: 10.1038/nsmb.2699] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/19/2013] [Indexed: 02/08/2023]
Abstract
Alternative splicing (AS) enables programmed diversity of gene expression across tissues and development. We show here that binding in distal intronic regions (>500 nucleotides (nt) from any exon) by Rbfox splicing factors important in development is extensive and is an active mode of splicing regulation. Similarly to exon-proximal sites, distal sites contain evolutionarily conserved GCATG sequences and are associated with AS activation and repression upon modulation of Rbfox abundance in human and mouse experimental systems. As a proof of principle, we validated the activity of two specific Rbfox enhancers in KIF21A and ENAH distal introns and showed that a conserved long-range RNA-RNA base-pairing interaction (an RNA bridge) is necessary for Rbfox-mediated exon inclusion in the ENAH gene. Thus we demonstrate a previously unknown RNA-mediated mechanism for AS control by distally bound RNA-binding proteins.
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Affiliation(s)
- Michael T Lovci
- 1] Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA. [2] Stem Cell Program, University of California, San Diego, La Jolla, California, USA. [3] Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
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Spletter ML, Schnorrer F. Transcriptional regulation and alternative splicing cooperate in muscle fiber-type specification in flies and mammals. Exp Cell Res 2013; 321:90-8. [PMID: 24145055 PMCID: PMC4040393 DOI: 10.1016/j.yexcr.2013.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 10/06/2013] [Accepted: 10/09/2013] [Indexed: 11/21/2022]
Abstract
Muscles coordinate body movements throughout the animal kingdom. Each skeletal muscle is built of large, multi-nucleated cells, called myofibers, which are classified into several functionally distinct types. The typical fiber-type composition of each muscle arises during development, and in mammals is extensively adjusted in response to postnatal exercise. Understanding how functionally distinct muscle fiber-types arise is important for unraveling the molecular basis of diseases from cardiomyopathies to muscular dystrophies. In this review, we focus on recent advances in Drosophila and mammals in understanding how muscle fiber-type specification is controlled by the regulation of transcription and alternative splicing. We illustrate the cooperation of general myogenic transcription factors with muscle fiber-type specific transcriptional regulators as a basic principle for fiber-type specification, which is conserved from flies to mammals. We also examine how regulated alternative splicing of sarcomeric proteins in both flies and mammals can directly instruct the physiological and biophysical differences between fiber-types. Thus, research in Drosophila can provide important mechanistic insight into muscle fiber specification, which is relevant to homologous processes in mammals and to the pathology of muscle diseases.
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Affiliation(s)
- Maria L Spletter
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Frank Schnorrer
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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Zhao WW. Intragenic deletion of RBFOX1 associated with neurodevelopmental/neuropsychiatric disorders and possibly other clinical presentations. Mol Cytogenet 2013; 6:26. [PMID: 23822903 PMCID: PMC3766065 DOI: 10.1186/1755-8166-6-26] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/30/2013] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND RBFOX1 is an important splicing factor regulating developmental and tissue-specific alternative splicing in heart, muscle, and neuronal tissues. Constitutional genetic defects in RBFOX1 are implicated in multiple medical conditions. RESULTS We identified 14 copy number variants (CNV) involving RBFOX1 from 2,124 consecutive pediatric patients referred for chromosomal microarray analysis (CMA), including 13 intragenic deletions and a single intragenic duplication. The clinical significances of the intragenic deletions of RBFOX1 were evaluated. CONCLUSIONS Our data strongly supports the associations of intragenic deletions of RBFOX1 with a diversity of neurodevelopmental and neuropsychiatric disorders, and possibly other clinical features.
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Affiliation(s)
- Wei-Wei Zhao
- Department of Molecular Pathology, KingMed Genome Diagnostic Laboratory, 2429 XinGangDong Road, Haizhu Science and Technology Building, Guangzhou 510330, China.
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