1
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Trujillo EM, Lee SR, Aguayo A, Torosian TC, Cripps RM. Enhanced expression of the myogenic factor Myocyte enhancer factor-2 in imaginal disc myoblasts activates a partial, but incomplete, muscle development program. Dev Biol 2024; 516:82-95. [PMID: 39111615 DOI: 10.1016/j.ydbio.2024.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 07/19/2024] [Accepted: 08/02/2024] [Indexed: 08/15/2024]
Abstract
The Myocyte enhancer factor-2 (MEF2) transcription factor plays a vital role in orchestrating muscle differentiation. While MEF2 cannot effectively induce myogenesis in naïve cells, it can potently accelerate myogenesis in mesodermal cells. This includes in Drosophila melanogaster imaginal disc myoblasts, where triggering premature muscle gene expression in these adult muscle progenitors has become a paradigm for understanding the regulation of the myogenic program. Here, we investigated the global consequences of MEF2 overexpression in the imaginal wing disc myoblasts, by combining RNA-sequencing with RT-qPCR and immunofluorescence. We observed the formation of sarcomere-like structures that contained both muscle and cytoplasmic myosin, and significant upregulation of muscle gene expression, especially genes essential for myofibril formation and function. These transcripts were functional since numerous myofibrillar proteins were detected in discs using immunofluorescence. Interestingly, muscle genes whose expression is restricted to the adult stages were not activated in these adult myoblasts. These studies confirm a broad activation of the myogenic program in response to MEF2 expression and suggest that additional regulatory factors are required for promoting the adult muscle-specific program. Our findings contribute to understanding the regulatory mechanisms governing muscle development and highlight the multifaceted role of MEF2 in orchestrating this intricate process.
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Affiliation(s)
| | - Samuel R Lee
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Antonio Aguayo
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Tylee C Torosian
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Richard M Cripps
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA.
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2
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Chechenova M, McLendon L, Dallas B, Stratton H, Kiani K, Gerberich E, Alekseyenko A, Tamba N, An S, Castillo L, Czajkowski E, Talley C, Brown A, Bryantsev AL. Muscle degeneration in aging Drosophila flies: the role of mechanical stress. Skelet Muscle 2024; 14:20. [PMID: 39164781 PMCID: PMC11334408 DOI: 10.1186/s13395-024-00352-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Accepted: 08/09/2024] [Indexed: 08/22/2024] Open
Abstract
Muscle wasting is a universal hallmark of aging which is displayed by a wide range of organisms, although the causes and mechanisms of this phenomenon are not fully understood. We used Drosophila to characterize the phenomenon of spontaneous muscle fiber degeneration (SMFD) during aging. We found that SMFD occurs across diverse types of somatic muscles, progresses with chronological age, and positively correlates with functional muscle decline. Data from vital dyes and morphological markers imply that degenerative fibers most likely die by necrosis. Mechanistically, SMFD is driven by the damage resulting from muscle contractions, and the nervous system may play a significant role in this process. Our quantitative model of SMFD assessment can be useful in identifying and validating novel genetic factors that influence aging-related muscle wasting.
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Affiliation(s)
- Maria Chechenova
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
- Present Affiliation: MNG Laboratories, A LabCorp Company, Atlanta, GA, USA
| | - Lilla McLendon
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Bracey Dallas
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Hannah Stratton
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Kaveh Kiani
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Erik Gerberich
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Alesia Alekseyenko
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Natasya Tamba
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - SooBin An
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Lizzet Castillo
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Emily Czajkowski
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
- Present Affiliation: Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Christina Talley
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA
| | - Austin Brown
- Department of Mathematics, Kennesaw State University, Kennesaw, GA, USA
| | - Anton L Bryantsev
- Department of Molecular and Cellular Biology, Kennesaw State University, 105 Marietta Dr., NW, Room 4004, MD 1201, Kennesaw, GA, 30144, USA.
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3
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Nikonova E, DeCata J, Canela M, Barz C, Esser A, Bouterwek J, Roy A, Gensler H, Heß M, Straub T, Forne I, Spletter ML. Bruno 1/CELF regulates splicing and cytoskeleton dynamics to ensure correct sarcomere assembly in Drosophila flight muscles. PLoS Biol 2024; 22:e3002575. [PMID: 38683844 PMCID: PMC11081514 DOI: 10.1371/journal.pbio.3002575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 05/09/2024] [Accepted: 03/04/2024] [Indexed: 05/02/2024] Open
Abstract
Muscles undergo developmental transitions in gene expression and alternative splicing that are necessary to refine sarcomere structure and contractility. CUG-BP and ETR-3-like (CELF) family RNA-binding proteins are important regulators of RNA processing during myogenesis that are misregulated in diseases such as Myotonic Dystrophy Type I (DM1). Here, we report a conserved function for Bruno 1 (Bru1, Arrest), a CELF1/2 family homolog in Drosophila, during early muscle myogenesis. Loss of Bru1 in flight muscles results in disorganization of the actin cytoskeleton leading to aberrant myofiber compaction and defects in pre-myofibril formation. Temporally restricted rescue and RNAi knockdown demonstrate that early cytoskeletal defects interfere with subsequent steps in sarcomere growth and maturation. Early defects are distinct from a later requirement for bru1 to regulate sarcomere assembly dynamics during myofiber maturation. We identify an imbalance in growth in sarcomere length and width during later stages of development as the mechanism driving abnormal radial growth, myofibril fusion, and the formation of hollow myofibrils in bru1 mutant muscle. Molecularly, we characterize a genome-wide transition from immature to mature sarcomere gene isoform expression in flight muscle development that is blocked in bru1 mutants. We further demonstrate that temporally restricted Bru1 rescue can partially alleviate hypercontraction in late pupal and adult stages, but it cannot restore myofiber function or correct structural deficits. Our results reveal the conserved nature of CELF function in regulating cytoskeletal dynamics in muscle development and demonstrate that defective RNA processing due to misexpression of CELF proteins causes wide-reaching structural defects and progressive malfunction of affected muscles that cannot be rescued by late-stage gene replacement.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Jenna DeCata
- School of Science and Engineering, Division of Biological and Biomedical Systems, Kansas City, Missouri, United States of America
| | - Marc Canela
- Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
| | - Christiane Barz
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, München, Germany
| | - Alexandra Esser
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Jessica Bouterwek
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Akanksha Roy
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, München, Germany
| | - Heidemarie Gensler
- Department of Systematic Zoology, Biocenter, Faculty of Biology, Ludwig-Maximilians-Universität München, München, Germany
| | - Martin Heß
- Department of Systematic Zoology, Biocenter, Faculty of Biology, Ludwig-Maximilians-Universität München, München, Germany
| | - Tobias Straub
- Biomedical Center, Bioinformatics Core Unit, Ludwig-Maximilians-Universität München, München, Germany
| | - Ignasi Forne
- Biomedical Center, Protein Analysis Unit, Ludwig-Maximilians-Universität München, München, Germany
| | - Maria L. Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, München, Germany
- School of Science and Engineering, Division of Biological and Biomedical Systems, Kansas City, Missouri, United States of America
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4
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Schöck F, González-Morales N. The insect perspective on Z-disc structure and biology. J Cell Sci 2022; 135:277280. [PMID: 36226637 DOI: 10.1242/jcs.260179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myofibrils are the intracellular structures formed by actin and myosin filaments. They are paracrystalline contractile cables with unusually well-defined dimensions. The sliding of actin past myosin filaments powers contractions, and the entire system is held in place by a structure called the Z-disc, which anchors the actin filaments. Myosin filaments, in turn, are anchored to another structure called the M-line. Most of the complex architecture of myofibrils can be reduced to studying the Z-disc, and recently, important advances regarding the arrangement and function of Z-discs in insects have been published. On a very small scale, we have detailed protein structure information. At the medium scale, we have cryo-electron microscopy maps, super-resolution microscopy and protein-protein interaction networks, while at the functional scale, phenotypic data are available from precise genetic manipulations. All these data aim to answer how the Z-disc works and how it is assembled. Here, we summarize recent data from insects and explore how it fits into our view of the Z-disc, myofibrils and, ultimately, muscles.
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Affiliation(s)
- Frieder Schöck
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1, Canada
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5
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Palu RAS, Owings KG, Garces JG, Nicol A. A natural genetic variation screen identifies insulin signaling, neuronal communication, and innate immunity as modifiers of hyperglycemia in the absence of Sirt1. G3 (BETHESDA, MD.) 2022; 12:jkac090. [PMID: 35435227 PMCID: PMC9157059 DOI: 10.1093/g3journal/jkac090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022]
Abstract
Variation in the onset, progression, and severity of symptoms associated with metabolic disorders such as diabetes impairs the diagnosis and treatment of at-risk patients. Diabetes symptoms, and patient variation in these symptoms, are attributed to a combination of genetic and environmental factors, but identifying the genes and pathways that modify diabetes in humans has proven difficult. A greater understanding of genetic modifiers and the ways in which they interact with metabolic pathways could improve the ability to predict a patient's risk for severe symptoms, as well as enhance the development of individualized therapeutic approaches. In this study, we use the Drosophila Genetic Reference Panel to identify genetic variation influencing hyperglycemia associated with loss of Sirt1 function. Through analysis of individual candidate functions, physical interaction networks, and gene set enrichment analysis, we identify not only modifiers involved in canonical glucose metabolism and insulin signaling, but also genes important for neuronal signaling and the innate immune response. Furthermore, reducing the expression of several of these candidates suppressed hyperglycemia, making them potential candidate therapeutic targets. These analyses showcase the diverse processes contributing to glucose homeostasis and open up several avenues of future investigation.
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Affiliation(s)
- Rebecca A S Palu
- Department of Biological Sciences, Purdue University-Fort Wayne, Fort Wayne, IN 46818, USA
| | - Katie G Owings
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - John G Garces
- Department of Biological Sciences, Purdue University-Fort Wayne, Fort Wayne, IN 46818, USA
| | - Audrey Nicol
- Department of Biological Sciences, Purdue University-Fort Wayne, Fort Wayne, IN 46818, USA
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6
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Nikonova E, Mukherjee A, Kamble K, Barz C, Nongthomba U, Spletter ML. Rbfox1 is required for myofibril development and maintaining fiber type-specific isoform expression in Drosophila muscles. Life Sci Alliance 2022; 5:5/4/e202101342. [PMID: 34996845 PMCID: PMC8742874 DOI: 10.26508/lsa.202101342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/24/2022] Open
Abstract
Protein isoform transitions confer muscle fibers with distinct properties and are regulated by differential transcription and alternative splicing. RNA-binding Fox protein 1 (Rbfox1) can affect both transcript levels and splicing, and is known to contribute to normal muscle development and physiology in vertebrates, although the detailed mechanisms remain obscure. In this study, we report that Rbfox1 contributes to the generation of adult muscle diversity in Drosophila Rbfox1 is differentially expressed among muscle fiber types, and RNAi knockdown causes a hypercontraction phenotype that leads to behavioral and eclosion defects. Misregulation of fiber type-specific gene and splice isoform expression, notably loss of an indirect flight muscle-specific isoform of Troponin-I that is critical for regulating myosin activity, leads to structural defects. We further show that Rbfox1 directly binds the 3'-UTR of target transcripts, regulates the expression level of myogenic transcription factors myocyte enhancer factor 2 and Salm, and both modulates expression of and genetically interacts with the CELF family RNA-binding protein Bruno1 (Bru1). Rbfox1 and Bru1 co-regulate fiber type-specific alternative splicing of structural genes, indicating that regulatory interactions between FOX and CELF family RNA-binding proteins are conserved in fly muscle. Rbfox1 thus affects muscle development by regulating fiber type-specific splicing and expression dynamics of identity genes and structural proteins.
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Affiliation(s)
- Elena Nikonova
- Department of Physiological Chemistry, Biomedical Center, Ludwig-Maximilians-Universität München, Martinsried-Planegg, Germany
| | - Amartya Mukherjee
- Department of Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bangalore, India
| | - Ketaki Kamble
- Department of Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bangalore, India
| | - Christiane Barz
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried-Planegg, Germany
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bangalore, India
| | - Maria L Spletter
- Department of Physiological Chemistry, Biomedical Center, Ludwig-Maximilians-Universität München, Martinsried-Planegg, Germany
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7
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Mechanobiology of muscle and myofibril morphogenesis. Cells Dev 2021; 168:203760. [PMID: 34863916 DOI: 10.1016/j.cdev.2021.203760] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 01/05/2023]
Abstract
Muscles generate forces for animal locomotion. The contractile apparatus of muscles is the sarcomere, a highly regular array of large actin and myosin filaments linked by gigantic titin springs. During muscle development many sarcomeres assemble in series into long periodic myofibrils that mechanically connect the attached skeleton elements. Thus, ATP-driven myosin forces can power movement of the skeleton. Here we review muscle and myofibril morphogenesis, with a particular focus on their mechanobiology. We describe recent progress on the molecular structure of sarcomeres and their mechanical connections to the skeleton. We discuss current models predicting how tension coordinates the assembly of key sarcomeric components to periodic myofibrils that then further mature during development. This requires transcriptional feedback mechanisms that may help to coordinate myofibril assembly and maturation states with the transcriptional program. To fuel the varying energy demands of muscles we also discuss the close mechanical interactions of myofibrils with mitochondria and nuclei to optimally support powerful or enduring muscle fibers.
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8
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Kao SY, Nikonova E, Chaabane S, Sabani A, Martitz A, Wittner A, Heemken J, Straub T, Spletter ML. A Candidate RNAi Screen Reveals Diverse RNA-Binding Protein Phenotypes in Drosophila Flight Muscle. Cells 2021; 10:2505. [PMID: 34685485 PMCID: PMC8534295 DOI: 10.3390/cells10102505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/14/2021] [Accepted: 09/18/2021] [Indexed: 12/30/2022] Open
Abstract
The proper regulation of RNA processing is critical for muscle development and the fine-tuning of contractile ability among muscle fiber-types. RNA binding proteins (RBPs) regulate the diverse steps in RNA processing, including alternative splicing, which generates fiber-type specific isoforms of structural proteins that confer contractile sarcomeres with distinct biomechanical properties. Alternative splicing is disrupted in muscle diseases such as myotonic dystrophy and dilated cardiomyopathy and is altered after intense exercise as well as with aging. It is therefore important to understand splicing and RBP function, but currently, only a small fraction of the hundreds of annotated RBPs expressed in muscle have been characterized. Here, we demonstrate the utility of Drosophila as a genetic model system to investigate basic developmental mechanisms of RBP function in myogenesis. We find that RBPs exhibit dynamic temporal and fiber-type specific expression patterns in mRNA-Seq data and display muscle-specific phenotypes. We performed knockdown with 105 RNAi hairpins targeting 35 RBPs and report associated lethality, flight, myofiber and sarcomere defects, including flight muscle phenotypes for Doa, Rm62, mub, mbl, sbr, and clu. Knockdown phenotypes of spliceosome components, as highlighted by phenotypes for A-complex components SF1 and Hrb87F (hnRNPA1), revealed level- and temporal-dependent myofibril defects. We further show that splicing mediated by SF1 and Hrb87F is necessary for Z-disc stability and proper myofibril development, and strong knockdown of either gene results in impaired localization of kettin to the Z-disc. Our results expand the number of RBPs with a described phenotype in muscle and underscore the diversity in myofibril and transcriptomic phenotypes associated with splicing defects. Drosophila is thus a powerful model to gain disease-relevant insight into cellular and molecular phenotypes observed when expression levels of splicing factors, spliceosome components and splicing dynamics are altered.
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Affiliation(s)
- Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Sabrina Chaabane
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Albiona Sabani
- Department of Biology, University of Wisconsin at Madison, 1117 W. Johnson St., Madison, WI 53706, USA;
| | - Alexandra Martitz
- Molecular Nutrition Medicine, Else Kröner-Fresenius Center, Technical University of Munich, 85354 Freising, Germany;
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Jakob Heemken
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Tobias Straub
- Biomedical Center, Bioinformatics Core Facility, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany;
| | - Maria L. Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
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9
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Czajkowski ER, Cisneros M, Garcia BS, Shen J, Cripps RM. The Drosophila CG1674 gene encodes a synaptopodin 2-like related protein that localizes to the Z-disc and is required for normal flight muscle development and function. Dev Dyn 2021; 250:99-110. [PMID: 32893414 PMCID: PMC7902442 DOI: 10.1002/dvdy.250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/12/2020] [Accepted: 09/01/2020] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND To identify novel myofibrillar components of the Drosophila flight muscles, we carried out a proteomic analysis of chemically demembranated flight muscle myofibrils, and characterized the knockdown phenotype of a novel gene identified in the screen, CG1674. RESULTS The CG1674 protein has some similarity to vertebrate synaptopodin 2-like, and when expressed as a FLAG-tagged fusion protein, it was localized during development to the Z-disc and cytoplasm. Knockdown of CG1674 expression affected the function of multiple muscle types, and defective flight in adults was accompanied by large actin-rich structures in the flight muscles that resembled overgrown Z-discs. Localization of CG1674 to the Z-disc depended predominantly upon presence of the Z-disc component alpha-actinin, but also depended upon other Z-disc components, including Mask, Zasp52, and Sals. We also observed re-localization of FLAG-CG1674 to the nucleus in Alpha-actinin and sals knockdown animals. CONCLUSIONS These studies identify and characterize a previously unreported myofibrillar component of Drosophila muscle that is necessary for proper myofibril assembly during development.
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Affiliation(s)
| | - Marilyn Cisneros
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Bianca S. Garcia
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Jim Shen
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Richard M. Cripps
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
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10
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Muscle development : a view from adult myogenesis in Drosophila. Semin Cell Dev Biol 2020; 104:39-50. [DOI: 10.1016/j.semcdb.2020.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/17/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023]
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11
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Poovathumkadavil P, Jagla K. Genetic Control of Muscle Diversification and Homeostasis: Insights from Drosophila. Cells 2020; 9:cells9061543. [PMID: 32630420 PMCID: PMC7349286 DOI: 10.3390/cells9061543] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/13/2022] Open
Abstract
In the fruit fly, Drosophila melanogaster, the larval somatic muscles or the adult thoracic flight and leg muscles are the major voluntary locomotory organs. They share several developmental and structural similarities with vertebrate skeletal muscles. To ensure appropriate activity levels for their functions such as hatching in the embryo, crawling in the larva, and jumping and flying in adult flies all muscle components need to be maintained in a functionally stable or homeostatic state despite constant strain. This requires that the muscles develop in a coordinated manner with appropriate connections to other cell types they communicate with. Various signaling pathways as well as extrinsic and intrinsic factors are known to play a role during Drosophila muscle development, diversification, and homeostasis. In this review, we discuss genetic control mechanisms of muscle contraction, development, and homeostasis with particular emphasis on the contractile unit of the muscle, the sarcomere.
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12
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Nikonova E, Kao SY, Spletter ML. Contributions of alternative splicing to muscle type development and function. Semin Cell Dev Biol 2020; 104:65-80. [PMID: 32070639 DOI: 10.1016/j.semcdb.2020.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/30/2022]
Abstract
Animals possess a wide variety of muscle types that support different kinds of movements. Different muscles have distinct locations, morphologies and contractile properties, raising the question of how muscle diversity is generated during development. Normal aging processes and muscle disorders differentially affect particular muscle types, thus understanding how muscles normally develop and are maintained provides insight into alterations in disease and senescence. As muscle structure and basic developmental mechanisms are highly conserved, many important insights into disease mechanisms in humans as well as into basic principles of muscle development have come from model organisms such as Drosophila, zebrafish and mouse. While transcriptional regulation has been characterized to play an important role in myogenesis, there is a growing recognition of the contributions of alternative splicing to myogenesis and the refinement of muscle function. Here we review our current understanding of muscle type specific alternative splicing, using examples of isoforms with distinct functions from both vertebrates and Drosophila. Future exploration of the vast potential of alternative splicing to fine-tune muscle development and function will likely uncover novel mechanisms of isoform-specific regulation and a more holistic understanding of muscle development, disease and aging.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität 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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13
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A Large Scale Systemic RNAi Screen in the Red Flour Beetle Tribolium castaneum Identifies Novel Genes Involved in Insect Muscle Development. G3-GENES GENOMES GENETICS 2019; 9:1009-1026. [PMID: 30733381 PMCID: PMC6469426 DOI: 10.1534/g3.118.200995] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although muscle development has been widely studied in Drosophila melanogaster there are still many gaps in our knowledge, and it is not known to which extent this knowledge can be transferred to other insects. To help in closing these gaps we participated in a large-scale RNAi screen that used the red flour beetle, Tribolium castaneum, as a screening platform. The effects of systemic RNAi were screened upon double-stranded RNA injections into appropriate muscle-EGFP tester strains. Injections into pupae were followed by the analysis of the late embryonic/early larval muscle patterns, and injections into larvae by the analysis of the adult thoracic muscle patterns. Herein we describe the results of the first-pass screens with pupal and larval injections, which covered ∼8,500 and ∼5,000 genes, respectively, of a total of ∼16,500 genes of the Tribolium genome. Apart from many genes known from Drosophila as regulators of muscle development, a collection of genes previously unconnected to muscle development yielded phenotypes in larval body wall and leg muscles as well as in indirect flight muscles. We then present the main candidates from the pupal injection screen that remained after being processed through a series of verification and selection steps. Further, we discuss why distinct though overlapping sets of genes are revealed by the Drosophila and Tribolium screening approaches.
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14
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Zheng ZZ, Sun X, Zhang B, Pu J, Jiang ZY, Li M, Fan YJ, Xu YZ. Alternative splicing regulation of doublesex gene by RNA-binding proteins in the silkworm Bombyx mori. RNA Biol 2019; 16:809-820. [PMID: 30836863 DOI: 10.1080/15476286.2019.1590177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Doublesex is highly conserved and sex-specifically spliced in insect sex-determination pathways, and its alternative splicing (AS) is regulated by Transformer, an exonic splicing activator, in the model system of Drosophila melanogaster. However, due to the lack of a transformer gene, AS regulation of doublesex remains unclear in Lepidoptera, which contain the economically important silkworm Bombyx mori and thousands of agricultural pests. Here, we use yeast three-hybrid system to screen for RNA-binding proteins that recognize sex-specific exons 3 and 4 of silkworm doublesex (Bm-dsx); this approach identified BxRBP1/Lark binding to the exon 3, and BxRBP2/TBPH and BxRBP3/Aret binding to the exon 4. Investigation of tissues shows that BxRBP1 and BxRBP2 have no sex specificity, but BxRBP3 has - three of its four isoforms are expressed with a sex-bias. Using novel sex-specific silkworm cell lines, we find that BxRBP1 and BxRBP3 directly interact with each other, and cooperatively function as splicing repressors. Over-expression of BxRBP1 and BxRBP3 isoforms efficiently inhibits splicing of the exons 3 and 4 in the female-specific cells and generates the male-specific isoform of Bm-dsx. We also demonstrate that the sex-determination upstream gene Masc regulates alternatively transcribed BxRBP3 isoforms. Thus, we identify a new regulatory mechanism of doublesex AS in the silkworm, revealing an evolutionary divergence in insect sex-determination.
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Affiliation(s)
- Zeng-Zhang Zheng
- a Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Science , Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai , China
| | - Xia Sun
- b College of Life Technology , Jiangsu University of Science and Technology , Zhenjiang , China
| | - Bei Zhang
- a Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Science , Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai , China
| | - Jia Pu
- a Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Science , Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai , China
| | - Ze-Yu Jiang
- a Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Science , Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai , China
| | - Muwang Li
- b College of Life Technology , Jiangsu University of Science and Technology , Zhenjiang , China
| | - Yu-Jie Fan
- c College of Life Science , Wuhan University , Wuhan , China
| | - Yong-Zhen Xu
- c College of Life Science , Wuhan University , Wuhan , China
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15
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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: 16] [Impact Index Per Article: 2.7] [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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16
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Bryantsev AL, Castillo L, Oas ST, Chechenova MB, Dohn TE, Lovato TL. Myogenesis in Drosophila melanogaster: Dissection of Distinct Muscle Types for Molecular Analysis. Methods Mol Biol 2019; 1889:267-281. [PMID: 30367420 DOI: 10.1007/978-1-4939-8897-6_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Drosophila is a useful model organism for studying the molecular signatures that define specific muscle types during myogenesis. It possesses significant genetic conservation with humans for muscle disease causing genes and a lack of redundancy that simplifies functional analysis. Traditional molecular methods can be utilized to understand muscle developmental processes such as Western blots, in situ hybridizations, RT-PCR and RNAseq, to name a few. However, one challenge for these molecular methods is the ability to dissect different muscle types. In this protocol we describe some useful techniques for extracting muscles from the pupal and adult stages of development using flight and jump muscles as an example.
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Affiliation(s)
- Anton L Bryantsev
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA, USA
| | - Lizzet Castillo
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Sandy T Oas
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Maria B Chechenova
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA, USA
| | - Tracy E Dohn
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA, USA
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - TyAnna L Lovato
- Department of Biology, University of New Mexico, Albuquerque, NM, USA.
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17
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Picchio L, Legagneux V, Deschamps S, Renaud Y, Chauveau S, Paillard L, Jagla K. Bruno-3 regulates sarcomere component expression and contributes to muscle phenotypes of myotonic dystrophy type 1. Dis Model Mech 2018; 11:dmm.031849. [PMID: 29716962 PMCID: PMC5992612 DOI: 10.1242/dmm.031849] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 04/18/2018] [Indexed: 01/22/2023] Open
Abstract
Steinert disease, or myotonic dystrophy type 1 (DM1), is a multisystemic disorder caused by toxic noncoding CUG repeat transcripts, leading to altered levels of two RNA binding factors, MBNL1 and CELF1. The contribution of CELF1 to DM1 phenotypes is controversial. Here, we show that the Drosophila CELF1 family member, Bru-3, contributes to pathogenic muscle defects observed in a Drosophila model of DM1. Bru-3 displays predominantly cytoplasmic expression in muscles and its muscle-specific overexpression causes a range of phenotypes also observed in the fly DM1 model, including affected motility, fiber splitting, reduced myofiber length and altered myoblast fusion. Interestingly, comparative genome-wide transcriptomic analyses revealed that Bru-3 negatively regulates levels of mRNAs encoding a set of sarcomere components, including Actn transcripts. Conversely, it acts as a positive regulator of Actn translation. As CELF1 displays predominantly cytoplasmic expression in differentiating C2C12 myotubes and binds to Actn mRNA, we hypothesize that it might exert analogous functions in vertebrate muscles. Altogether, we propose that cytoplasmic Bru-3 contributes to DM1 pathogenesis in a Drosophila model by regulating sarcomeric transcripts and protein levels.
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Affiliation(s)
- Lucie Picchio
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Vincent Legagneux
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France.,Inserm UMR1085 IRSET, Université de Rennes 1, 35000 Rennes, France.,CNRS-Université de Rennes1-INRIA, UMR6074 IRISA, 35000 Rennes, France
| | - Stephane Deschamps
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France
| | - Yoan Renaud
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Sabine Chauveau
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Luc Paillard
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France
| | - Krzysztof Jagla
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
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18
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Segal D. Live Imaging of Myogenesis in Indirect Flight Muscles in Drosophila. Bio Protoc 2017; 7:e2377. [PMID: 34541118 DOI: 10.21769/bioprotoc.2377] [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: 03/01/2017] [Revised: 05/30/2017] [Accepted: 06/04/2017] [Indexed: 11/02/2022] Open
Abstract
The indirect flight muscles (IFMs) are the largest muscles in the fly, making up the bulk of the adult thorax. IFMs in Drosophila are generated during pupariation by fusion of hundreds of muscle precursor cells (myoblasts) with larval muscle templates (myotubes). Prominent features, including the large number of fusion events, the structural similarity to vertebrate muscles, and the amenability to the powerful genetic techniques of the Drosophila system make the IFMs an attractive system to study muscle cell fusion. Here we describe methods for live imaging of IFMs, both in intact pupae, and in isolated IFMs ex-vivo. The protocols elaborated upon here were used in the manuscript by ( Segal et al., 2016 ).
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Affiliation(s)
- Dagan Segal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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19
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Sarov M, Barz C, Jambor H, Hein MY, Schmied C, Suchold D, Stender B, Janosch S, K J VV, Krishnan RT, Krishnamoorthy A, Ferreira IRS, Ejsmont RK, Finkl K, Hasse S, Kämpfer P, Plewka N, Vinis E, Schloissnig S, Knust E, Hartenstein V, Mann M, Ramaswami M, VijayRaghavan K, Tomancak P, Schnorrer F. A genome-wide resource for the analysis of protein localisation in Drosophila. eLife 2016; 5:e12068. [PMID: 26896675 PMCID: PMC4805545 DOI: 10.7554/elife.12068] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/19/2016] [Indexed: 02/07/2023] Open
Abstract
The Drosophila genome contains >13000 protein-coding genes, the majority of which remain poorly investigated. Important reasons include the lack of antibodies or reporter constructs to visualise these proteins. Here, we present a genome-wide fosmid library of 10000 GFP-tagged clones, comprising tagged genes and most of their regulatory information. For 880 tagged proteins, we created transgenic lines, and for a total of 207 lines, we assessed protein expression and localisation in ovaries, embryos, pupae or adults by stainings and live imaging approaches. Importantly, we visualised many proteins at endogenous expression levels and found a large fraction of them localising to subcellular compartments. By applying genetic complementation tests, we estimate that about two-thirds of the tagged proteins are functional. Moreover, these tagged proteins enable interaction proteomics from developing pupae and adult flies. Taken together, this resource will boost systematic analysis of protein expression and localisation in various cellular and developmental contexts. DOI:http://dx.doi.org/10.7554/eLife.12068.001 The fruit fly Drosophila melanogaster is a popular model organism in biological research. Studies using Drosophila have led to important insights into human biology, because related proteins often fulfil similar roles in flies and humans. Thus, studying the role of a protein in Drosophila can teach us about what it might do in a human. To fulfil their biological roles, proteins often occupy particular locations inside cells, such as the cell’s nucleus or surface membrane. Many proteins are also only found in specific types of cell, such as neurons or muscle cells. A protein’s location thus provides clues about what it does, however cells contain many thousands of proteins and identifying the location of each one is a herculean task. Sarov et al. took on this challenge and developed a new resource to study the localisation of all Drosophila proteins during this animal’s development. First, genetic engineering was used to tag thousands of Drosophila proteins with a green fluorescent protein, so that they could be tracked under a microscope. Sarov et al. tagged about 10000 Drosophila proteins in bacteria, and then introduced almost 900 of them into flies to create genetically modified flies. Each fly line contains an extra copy of the tagged gene that codes for one tagged protein. About two-thirds of these tagged proteins appeared to work normally after they were introduced into flies. Sarov et al. then looked at over 200 of these fly lines in more detail and observed that many of the proteins were found in particular cell types and localized to specific parts of the cells. Video imaging of the tagged proteins in living fruit fly embryos and pupae revealed the proteins’ movements, while other techniques showed which proteins bind to the tagged proteins, and may therefore work together in protein complexes. This resource is openly available to the community, and so researchers can use it to study their favourite protein and gain new insights into how proteins work and are regulated during Drosophila development. Following on from this work, the next challenge will be to create more flies carrying tagged proteins, and to swap the green fluorescent tag with other experimentally useful tags. DOI:http://dx.doi.org/10.7554/eLife.12068.002
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Affiliation(s)
- Mihail Sarov
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Christiane Barz
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Helena Jambor
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Marco Y Hein
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | | | - Dana Suchold
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Bettina Stender
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Stephan Janosch
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Vinay Vikas K J
- Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - R T Krishnan
- Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Aishwarya Krishnamoorthy
- Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Irene R S Ferreira
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | | | - Katja Finkl
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Susanne Hasse
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Philipp Kämpfer
- Heidelberg Institute of Theoretical Studies, Heidelberg, Germany
| | - Nicole Plewka
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Elisabeth Vinis
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | | | - Elisabeth Knust
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Mani Ramaswami
- Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - K VijayRaghavan
- Centre for Cellular and Molecular Platforms, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Pavel Tomancak
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Frank Schnorrer
- Muscle Dynamics Group, Max Planck Institute of Biochemistry, Martinsried, Germany
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20
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Zappia MP, Frolov MV. E2F function in muscle growth is necessary and sufficient for viability in Drosophila. Nat Commun 2016; 7:10509. [PMID: 26823289 PMCID: PMC4740182 DOI: 10.1038/ncomms10509] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/22/2015] [Indexed: 01/08/2023] Open
Abstract
The E2F transcription factor is a key cell cycle regulator. However, the inactivation of the entire E2F family in Drosophila is permissive throughout most of animal development until pupation when lethality occurs. Here we show that E2F function in the adult skeletal muscle is essential for animal viability since providing E2F function in muscles rescues the lethality of the whole-body E2F-deficient animals. Muscle-specific loss of E2F results in a significant reduction in muscle mass and thinner myofibrils. We demonstrate that E2F is dispensable for proliferation of muscle progenitor cells, but is required during late myogenesis to directly control the expression of a set of muscle-specific genes. Interestingly, E2f1 provides a major contribution to the regulation of myogenic function, while E2f2 appears to be less important. These findings identify a key function of E2F in skeletal muscle required for animal viability, and illustrate how the cell cycle regulator is repurposed in post-mitotic cells.
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Affiliation(s)
- Maria Paula Zappia
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 S Ashland Avenue, Chicago, Illinois 60607, USA
| | - Maxim V. Frolov
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 S Ashland Avenue, Chicago, Illinois 60607, USA
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21
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Dobi KC, Schulman VK, Baylies MK. Specification of the somatic musculature in Drosophila. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:357-75. [PMID: 25728002 PMCID: PMC4456285 DOI: 10.1002/wdev.182] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/16/2015] [Accepted: 02/04/2015] [Indexed: 11/09/2022]
Abstract
The somatic muscle system formed during Drosophila embryogenesis is required for larvae to hatch, feed, and crawl. This system is replaced in the pupa by a new adult muscle set, responsible for activities such as feeding, walking, and flight. Both the larval and adult muscle systems are comprised of distinct muscle fibers to serve these specific motor functions. In this way, the Drosophila musculature is a valuable model for patterning within a single tissue: while all muscle cells share properties such as the contractile apparatus, properties such as size, position, and number of nuclei are unique for a particular muscle. In the embryo, diversification of muscle fibers relies first on signaling cascades that pattern the mesoderm. Subsequently, the combinatorial expression of specific transcription factors leads muscle fibers to adopt particular sizes, shapes, and orientations. Adult muscle precursors (AMPs), set aside during embryonic development, proliferate during the larval phases and seed the formation of the abdominal, leg, and flight muscles in the adult fly. Adult muscle fibers may either be formed de novo from the fusion of the AMPs, or are created by the binding of AMPs to an existing larval muscle. While less is known about adult muscle specification compared to the larva, expression of specific transcription factors is also important for its diversification. Increasingly, the mechanisms required for the diversification of fly muscle have found parallels in vertebrate systems and mark Drosophila as a robust model system to examine questions about how diverse cell types are generated within an organism.
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Affiliation(s)
- Krista C. Dobi
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Victoria K. Schulman
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
| | - Mary K. Baylies
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
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22
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Spletter ML, Barz C, Yeroslaviz A, Schönbauer C, Ferreira IRS, Sarov M, Gerlach D, Stark A, Habermann BH, Schnorrer F. The RNA-binding protein Arrest (Bruno) regulates alternative splicing to enable myofibril maturation in Drosophila flight muscle. EMBO Rep 2014; 16:178-91. [PMID: 25532219 PMCID: PMC4328745 DOI: 10.15252/embr.201439791] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Drosophila, fibrillar flight muscles (IFMs) enable flight, while tubular muscles mediate other body movements. Here, we use RNA-sequencing and isoform-specific reporters to show that spalt major (salm) determines fibrillar muscle physiology by regulating transcription and alternative splicing of a large set of sarcomeric proteins. We identify the RNA-binding protein Arrest (Aret, Bruno) as downstream of salm. Aret shuttles between the cytoplasm and nuclei and is essential for myofibril maturation and sarcomere growth of IFMs. Molecularly, Aret regulates IFM-specific splicing of various salm-dependent sarcomeric targets, including Stretchin and wupA (TnI), and thus maintains muscle fiber integrity. As Aret and its sarcomeric targets are evolutionarily conserved, similar principles may regulate mammalian muscle morphogenesis.
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Affiliation(s)
| | | | | | | | | | - Mihail Sarov
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany
| | - Daniel Gerlach
- Research Institute of Molecular Pathology (IMP) Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP) Vienna Biocenter (VBC), Vienna, Austria
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23
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Leslie M. A storehouse for splicing proteins? J Biophys Biochem Cytol 2014. [PMCID: PMC4178972 DOI: 10.1083/jcb.2067if] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Researchers stumble on new domain within the nucleus.
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