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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: 6] [Impact Index Per Article: 1.5] [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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Spletter ML, Barz C, Yeroslaviz A, Zhang X, Lemke SB, Bonnard A, Brunner E, Cardone G, Basler K, Habermann BH, Schnorrer F. A transcriptomics resource reveals a transcriptional transition during ordered sarcomere morphogenesis in flight muscle. eLife 2018; 7:34058. [PMID: 29846170 PMCID: PMC6005683 DOI: 10.7554/elife.34058] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 05/26/2018] [Indexed: 01/07/2023] Open
Abstract
Muscles organise pseudo-crystalline arrays of actin, myosin and titin filaments to build force-producing sarcomeres. To study sarcomerogenesis, we have generated a transcriptomics resource of developing Drosophila flight muscles and identified 40 distinct expression profile clusters. Strikingly, most sarcomeric components group in two clusters, which are strongly induced after all myofibrils have been assembled, indicating a transcriptional transition during myofibrillogenesis. Following myofibril assembly, many short sarcomeres are added to each myofibril. Subsequently, all sarcomeres mature, reaching 1.5 µm diameter and 3.2 µm length and acquiring stretch-sensitivity. The efficient induction of the transcriptional transition during myofibrillogenesis, including the transcriptional boost of sarcomeric components, requires in part the transcriptional regulator Spalt major. As a consequence of Spalt knock-down, sarcomere maturation is defective and fibers fail to gain stretch-sensitivity. Together, this defines an ordered sarcomere morphogenesis process under precise transcriptional control - a concept that may also apply to vertebrate muscle or heart development.
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Affiliation(s)
- Maria L Spletter
- Muscle Dynamics GroupMax Planck Institute of BiochemistryMartinsriedGermany
- Biomedical Center, Physiological ChemistryLudwig-Maximilians-Universität MünchenMartinsriedGermany
| | - Christiane Barz
- Muscle Dynamics GroupMax Planck Institute of BiochemistryMartinsriedGermany
| | - Assa Yeroslaviz
- Computational Biology GroupMax Planck Institute of BiochemistryMartinsriedGermany
| | - Xu Zhang
- Muscle Dynamics GroupMax Planck Institute of BiochemistryMartinsriedGermany
- Aix Marseille Univ, CNRS, IBDMMarseilleFrance
- School of Life Science and EngineeringFoshan UniversityGuangdongChina
| | - Sandra B Lemke
- Muscle Dynamics GroupMax Planck Institute of BiochemistryMartinsriedGermany
| | - Adrien Bonnard
- Aix Marseille Univ, CNRS, IBDMMarseilleFrance
- Aix Marseille Univ, INSERM, TAGCMarseilleFrance
| | - Erich Brunner
- Institute of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
| | - Giovanni Cardone
- Imaging FacilityMax Planck Institute of BiochemistryMartinsriedGermany
| | - Konrad Basler
- Institute of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
| | - Bianca H Habermann
- Computational Biology GroupMax Planck Institute of BiochemistryMartinsriedGermany
- Aix Marseille Univ, CNRS, IBDMMarseilleFrance
- Aix Marseille Univ, INSERM, TAGCMarseilleFrance
| | - Frank Schnorrer
- Muscle Dynamics GroupMax Planck Institute of BiochemistryMartinsriedGermany
- Aix Marseille Univ, CNRS, IBDMMarseilleFrance
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Arredondo JJ, Vivar J, Laine-Menéndez S, Martínez-Morentin L, Cervera M. CF2 transcription factor is involved in the regulation of Mef2 RNA levels, nuclei number and muscle fiber size. PLoS One 2017; 12:e0179194. [PMID: 28617826 PMCID: PMC5472297 DOI: 10.1371/journal.pone.0179194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 05/25/2017] [Indexed: 11/26/2022] Open
Abstract
CF2 and Mef2 influence a variety of developmental muscle processes at distinct stages of development. Nevertheless, the exact nature of the CF2-Mef2 relationship and its effects on muscle building remain yet to be resolved. Here, we explored the regulatory role of CF2 in the Drosophila embryo muscle formation. To address this question and not having proper null CF2 mutants we exploited loss or gain of function strategies to study the contribution of CF2 to Mef2 transcription regulation and to muscle formation. Our data point to CF2 as a factor involved in the regulation of muscle final size and/or the number of nuclei present in each muscle. This function is independent of its role as a Mef2 collaborative factor in the transcriptional regulation of muscle-structural genes. Although Mef2 expression patterns do not change, reductions or increases in parallel in CF2 and Mef2 transcript abundance were observed in interfered and overexpressed CF2 embryos. Since CF2 expression variations yield altered Mef2 expression levels but with correct spatio-temporal Mef2 expression patterns, it can be concluded that only the mechanism controlling expression levels is de-regulated. Here, it is proposed that CF2 regulates Mef2 expression through a Feedforward Loop circuit.
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Affiliation(s)
- Juan J. Arredondo
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), c/ Arzobispo Morcillo 4, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail: (JJA); (MC)
| | - Jorge Vivar
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), c/ Arzobispo Morcillo 4, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Sara Laine-Menéndez
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), c/ Arzobispo Morcillo 4, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Leticia Martínez-Morentin
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), c/ Arzobispo Morcillo 4, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Margarita Cervera
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC and Centro de Investigación Biomédica en Red (CIBERER), c/ Arzobispo Morcillo 4, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail: (JJA); (MC)
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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: 3.9] [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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A cis-regulatory mutation in troponin-I of Drosophila reveals the importance of proper stoichiometry of structural proteins during muscle assembly. Genetics 2015; 200:149-65. [PMID: 25747460 DOI: 10.1534/genetics.115.175604] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 03/01/2015] [Indexed: 02/02/2023] Open
Abstract
Rapid and high wing-beat frequencies achieved during insect flight are powered by the indirect flight muscles, the largest group of muscles present in the thorax. Any anomaly during the assembly and/or structural impairment of the indirect flight muscles gives rise to a flightless phenotype. Multiple mutagenesis screens in Drosophila melanogaster for defective flight behavior have led to the isolation and characterization of mutations that have been instrumental in the identification of many proteins and residues that are important for muscle assembly, function, and disease. In this article, we present a molecular-genetic characterization of a flightless mutation, flightless-H (fliH), originally designated as heldup-a (hdp-a). We show that fliH is a cis-regulatory mutation of the wings up A (wupA) gene, which codes for the troponin-I protein, one of the troponin complex proteins, involved in regulation of muscle contraction. The mutation leads to reduced levels of troponin-I transcript and protein. In addition to this, there is also coordinated reduction in transcript and protein levels of other structural protein isoforms that are part of the troponin complex. The altered transcript and protein stoichiometry ultimately culminates in unregulated acto-myosin interactions and a hypercontraction muscle phenotype. Our results shed new insights into the importance of maintaining the stoichiometry of structural proteins during muscle assembly for proper function with implications for the identification of mutations and disease phenotypes in other species, including humans.
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Yáñez-Cuna JO, Dinh HQ, Kvon EZ, Shlyueva D, Stark A. Uncovering cis-regulatory sequence requirements for context-specific transcription factor binding. Genome Res 2012; 22:2018-30. [PMID: 22534400 PMCID: PMC3460196 DOI: 10.1101/gr.132811.111] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The regulation of gene expression is mediated at the transcriptional level by enhancer regions that are bound by sequence-specific transcription factors (TFs). Recent studies have shown that the in vivo binding sites of single TFs differ between developmental or cellular contexts. How this context-specific binding is encoded in the cis-regulatory DNA sequence has, however, remained unclear. We computationally dissect context-specific TF binding sites in Drosophila, Caenorhabditis elegans, mouse, and human and find distinct combinations of sequence motifs for partner factors, which are predictive and reveal specific motif requirements of individual binding sites. We predict that TF binding in the early Drosophila embryo depends on motifs for the early zygotic TFs Vielfaltig (also known as Zelda) and Tramtrack. We validate experimentally that the activity of Twist-bound enhancers and Twist binding itself depend on Vielfaltig motifs, suggesting that Vielfaltig is more generally important for early transcription. Our finding that the motif content can predict context-specific binding and that the predictions work across different Drosophila species suggests that characteristic motif combinations are shared between sites, revealing context-specific motif codes (cis-regulatory signatures), which appear to be conserved during evolution. Taken together, this study establishes a novel approach to derive predictive cis-regulatory motif requirements for individual TF binding sites and enhancers. Importantly, the method is generally applicable across different cell types and organisms to elucidate cis-regulatory sequence determinants and the corresponding trans-acting factors from the increasing number of tissue- and cell-type-specific TF binding studies.
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Bryantsev AL, Baker PW, Lovato TL, Jaramillo MS, Cripps RM. Differential requirements for Myocyte Enhancer Factor-2 during adult myogenesis in Drosophila. Dev Biol 2011; 361:191-207. [PMID: 22008792 DOI: 10.1016/j.ydbio.2011.09.031] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 08/27/2011] [Accepted: 09/27/2011] [Indexed: 11/27/2022]
Abstract
Identifying the genetic program that leads to formation of functionally and morphologically distinct muscle fibers is one of the major challenges in developmental biology. In Drosophila, the Myocyte Enhancer Factor-2 (MEF2) transcription factor is important for all types of embryonic muscle differentiation. In this study we investigated the role of MEF2 at different stages of adult skeletal muscle formation, where a diverse group of specialized muscles arises. Through stage- and tissue-specific expression of Mef2 RNAi constructs, we demonstrate that MEF2 is critical at the early stages of adult myoblast fusion: mutant myoblasts are attracted normally to their founder cell targets, but are unable to fuse to form myotubes. Interestingly, ablation of Mef2 expression at later stages of development showed MEF2 to be more dispensable for structural gene expression: after myoblast fusion, Mef2 knockdown did not interrupt expression of major structural gene transcripts, and myofibrils were formed. However, the MEF2-depleted fibers showed impaired integrity and a lack of fibrillar organization. When Mef2 RNAi was induced in muscles following eclosion, we found no adverse effects of attenuating Mef2 function. We conclude that in the context of adult myogenesis, MEF2 remains an essential factor, participating in control of myoblast fusion, and myofibrillogenesis in developing myotubes. However, MEF2 does not show a major requirement in the maintenance of muscle structural gene expression. Our findings point to the importance of a diversity of regulatory factors that are required for the formation and function of the distinct muscle fibers found in animals.
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Affiliation(s)
- Anton L Bryantsev
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
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High conservation of transcription factor binding and evidence for combinatorial regulation across six Drosophila species. Nat Genet 2011; 43:414-20. [PMID: 21478888 DOI: 10.1038/ng.808] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/21/2011] [Indexed: 12/13/2022]
Abstract
The binding of some transcription factors has been shown to diverge substantially between closely related species. Here we show that the binding of the developmental transcription factor Twist is highly conserved across six Drosophila species, revealing strong functional constraints at its enhancers. Conserved binding correlates with sequence motifs for Twist and its partners, permitting the de novo discovery of their combinatorial binding. It also includes over 10,000 low-occupancy sites near the detection limit, which tend to mark enhancers of later developmental stages. These results suggest that developmental enhancers can be highly evolutionarily constrained, presumably because of their complex combinatorial nature.
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Gajewski KM, Schulz RA. CF2 represses Actin 88F gene expression and maintains filament balance during indirect flight muscle development in Drosophila. PLoS One 2010; 5:e10713. [PMID: 20520827 PMCID: PMC2876027 DOI: 10.1371/journal.pone.0010713] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 03/28/2010] [Indexed: 11/19/2022] Open
Abstract
The zinc finger protein CF2 is a characterized activator of muscle structural genes in the body wall muscles of the Drosophila larva. To investigate the function of CF2 in the indirect flight muscle (IFM), we examined the phenotypes of flies bearing five homozygous viable mutations. The gross structure of the IFM was not affected, but the stronger hypomorphic alleles caused an increase of up to 1.5X in the diameter of the myofibrils. This size increase did not cause any disruption of the hexameric arrangement of thick and thin filaments. RT-PCR analysis revealed an increase in the transcription of several structural genes. Ectopic overexpression of CF2 in the developing IFM disrupts muscle formation. While our results indicate a role for CF2 as a direct negative regulator of the thin filament protein gene Actin 88F (Act88F), effects on levels of transcripts of myosin heavy chain (mhc) appear to be indirect. This role is in direct contrast to that described in the larval muscles, where CF2 activates structural gene expression. The variation in myofibril phenotypes of CF2 mutants suggest the CF2 may have separate functions in fine-tuning expression of structural genes to insure proper filament stoichiometry, and monitoring and/or controlling the final myofibril size.
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Affiliation(s)
- Kathleen M Gajewski
- Department of Systems Biology, University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
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Juneja P, Lazzaro BP. Haplotype structure and expression divergence at the Drosophila cellular immune gene eater. Mol Biol Evol 2010; 27:2284-99. [PMID: 20444883 DOI: 10.1093/molbev/msq114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The protein Eater plays an important role in microbial recognition and defensive phagocytosis in Drosophila melanogaster. We sequenced multiple alleles of the eater gene from an African and a North American population of D. melanogaster and found signatures of a partial selective sweep in North America that is localized around the second intron. This pattern is consistent with local adaptation to novel selective pressures during range expansion out of Africa. The North American sample is divided into two predominant haplotype groups, and the putatively selected haplotype is associated with a significantly higher gene expression level, suggesting that gene regulation is a possible target of selection. The eater alleles contain from 22 to 40 repeat units that are characterized by the presence of a cysteine-rich NIM motif. NIM repeats in the structural stalk of the protein exhibit concerted evolution as a function of physical location in the repeat array. Several NIM repeats within eater have previously been implicated in binding to microbial ligands, a function which in principle might subject them to special evolutionary pressures. However, we find no evidence of elevated positive selection on these pathogen-interacting units. Our study presents an instance where gene expression rather than protein structure is thought to drive the adaptive evolution of a pathogen recognition molecule in the immune system.
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Affiliation(s)
- Punita Juneja
- Department of Entomology, Cornell University, Ithaca, New York, USA.
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Guerrero L, Marco-Ferreres R, Serrano AL, Arredondo JJ, Cervera M. Secondary enhancers synergise with primary enhancers to guarantee fine-tuned muscle gene expression. Dev Biol 2010; 337:16-28. [DOI: 10.1016/j.ydbio.2009.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 09/15/2009] [Accepted: 10/03/2009] [Indexed: 11/27/2022]
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