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Inwood SN, Harrop TWR, Shields MW, Goldson SL, Dearden PK. Immune system modulation & virus transmission during parasitism identified by multi-species transcriptomics of a declining insect biocontrol system. BMC Genomics 2024; 25:311. [PMID: 38532315 DOI: 10.1186/s12864-024-10215-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND The Argentine stem weevil (ASW, Listronotus bonariensis) is a significant pasture pest in Aotearoa New Zealand, primarily controlled by the parasitoid biocontrol agent Microctonus hyperodae. Despite providing effective control of ASW soon after release, M. hyperodae parasitism rates have since declined significantly, with ASW hypothesised to have evolved resistance to its biocontrol agent. While the parasitism arsenal of M. hyperodae has previously been investigated, revealing many venom components and an exogenous novel DNA virus Microctonus hyperodae filamentous virus (MhFV), the effects of said arsenal on gene expression in ASW during parasitism have not been examined. In this study, we performed a multi-species transcriptomic analysis to investigate the biology of ASW parasitism by M. hyperodae, as well as the decline in efficacy of this biocontrol system. RESULTS The transcriptomic response of ASW to parasitism by M. hyperodae involves modulation of the weevil's innate immune system, flight muscle components, and lipid and glucose metabolism. The multispecies approach also revealed continued expression of venom components in parasitised ASW, as well as the transmission of MhFV to weevils during parasitism and some interrupted parasitism attempts. Transcriptomics did not detect a clear indication of parasitoid avoidance or other mechanisms to explain biocontrol decline. CONCLUSIONS This study has expanded our understanding of interactions between M. hyperodae and ASW in a biocontrol system of critical importance to Aotearoa-New Zealand's agricultural economy. Transmission of MhFV to ASW during successful and interrupted parasitism attempts may link to a premature mortality phenomenon in ASW, hypothesised to be a result of a toxin-antitoxin system. Further research into MhFV and its potential role in ASW premature mortality is required to explore whether manipulation of this viral infection has the potential to increase biocontrol efficacy in future.
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Affiliation(s)
- Sarah N Inwood
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - Thomas W R Harrop
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand
- Melbourne Bioinformatics, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Morgan W Shields
- BioProtection Research Centre, Lincoln University, Lincoln, New Zealand
| | - Stephen L Goldson
- Biocontrol and Biosecurity Group, AgResearch Limited, Lincoln, Aotearoa, New Zealand
| | - Peter K Dearden
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand.
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2
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Wishard R, Jayaram M, Ramesh SR, Nongthomba U. Spatial and temporal requirement of Mlp60A isoforms during muscle development and function in Drosophila melanogaster. Exp Cell Res 2023; 422:113430. [PMID: 36423661 DOI: 10.1016/j.yexcr.2022.113430] [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: 07/23/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 11/23/2022]
Abstract
Many myofibrillar proteins undergo isoform switching in a spatio-temporal manner during muscle development. The biological significance of the variants of several of these myofibrillar proteins remains elusive. One such myofibrillar protein, the Muscle LIM Protein (MLP), is a vital component of the Z-discs. In this paper, we show that one of the Drosophila MLP encoding genes, Mlp60A, gives rise to two isoforms: a short (279 bp, 10 kDa) and a long (1461 bp, 54 kDa) one. The short isoform is expressed throughout development, but the long isoform is adult-specific, being the dominant of the two isoforms in the indirect flight muscles (IFMs). A concomitant, muscle-specific knockdown of both isoforms leads to partial developmental lethality, with most of the surviving flies being flight defective. A global loss of both isoforms in a Mlp60A-null background also leads to developmental lethality, with muscle defects in the individuals that survive to the third instar larval stage. This lethality could be rescued partially by a muscle-specific overexpression of the short isoform. Genetic perturbation of only the long isoform, through a P-element insertion in the long isoform-specific coding sequence, leads to defective flight, in around 90% of the flies. This phenotype was completely rescued when the P-element insertion was precisely excised from the locus. Hence, our data show that the two Mlp60A isoforms are functionally specialized: the short isoform being essential for normal embryonic muscle development and the long isoform being necessary for normal adult flight muscle function.
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Affiliation(s)
- Rohan Wishard
- Department of Molecular Reproduction, Development and Genetics; Indian Institute of Science, Bengaluru, 560012, India.
| | - Mohan Jayaram
- Department of Molecular Reproduction, Development and Genetics; Indian Institute of Science, Bengaluru, 560012, India; Department of Studies in Zoology, University of Mysore, Manasgangotri, Mysuru, 570006, India
| | - Saraf R Ramesh
- Department of Studies in Zoology, University of Mysore, Manasgangotri, Mysuru, 570006, India; Department of Life Sciences, Pooja Bhagvat Memorial Mahajana Education Center, K. R. S. Road, Mysuru, 570016, India
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics; Indian Institute of Science, Bengaluru, 560012, India.
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3
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Katti P, Ajayi PT, Aponte A, Bleck CKE, Glancy B. Identification of evolutionarily conserved regulators of muscle mitochondrial network organization. Nat Commun 2022; 13:6622. [PMID: 36333356 PMCID: PMC9636386 DOI: 10.1038/s41467-022-34445-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial networks provide coordinated energy distribution throughout muscle cells. However, pathways specifying mitochondrial networks are incompletely understood and it is unclear how they might affect contractile fiber-type. Here, we show that natural energetic demands placed on Drosophila melanogaster muscles yield native cell-types among which contractile and mitochondrial network-types are regulated differentially. Proteomic analyses of indirect flight, jump, and leg muscles, together with muscles misexpressing known fiber-type specification factor salm, identified transcription factors H15 and cut as potential mitochondrial network regulators. We demonstrate H15 operates downstream of salm regulating flight muscle contractile and mitochondrial network-type. Conversely, H15 regulates mitochondrial network configuration but not contractile type in jump and leg muscles. Further, we find that cut regulates salm expression in flight muscles and mitochondrial network configuration in leg muscles. These data indicate cell type-specific regulation of muscle mitochondrial network organization through evolutionarily conserved transcription factors cut, salm, and H15.
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Affiliation(s)
- Prasanna Katti
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Peter T Ajayi
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Angel Aponte
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Christopher K E Bleck
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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4
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Katti P, Hall AS, Parry HA, Ajayi PT, Kim Y, Willingham TB, Bleck CKE, Wen H, Glancy B. Mitochondrial network configuration influences sarcomere and myosin filament structure in striated muscles. Nat Commun 2022; 13:6058. [PMID: 36229433 PMCID: PMC9561657 DOI: 10.1038/s41467-022-33678-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
Sustained muscle contraction occurs through interactions between actin and myosin filaments within sarcomeres and requires a constant supply of adenosine triphosphate (ATP) from nearby mitochondria. However, it remains unclear how different physical configurations between sarcomeres and mitochondria alter the energetic support for contractile function. Here, we show that sarcomere cross-sectional area (CSA) varies along its length in a cell type-dependent manner where the reduction in Z-disk CSA relative to the sarcomere center is closely coordinated with mitochondrial network configuration in flies, mice, and humans. Further, we find myosin filaments near the sarcomere periphery are curved relative to interior filaments with greater curvature for filaments near mitochondria compared to sarcoplasmic reticulum. Finally, we demonstrate variable myosin filament lattice spacing between filament ends and filament centers in a cell type-dependent manner. These data suggest both sarcomere structure and myofilament interactions are influenced by the location and orientation of mitochondria within muscle cells.
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Affiliation(s)
- Prasanna Katti
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Hailey A Parry
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Peter T Ajayi
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuho Kim
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - T Bradley Willingham
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christopher K E Bleck
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Han Wen
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brian Glancy
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health Bethesda, Bethesda, MD, USA.
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5
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Liang HF, Li XD. Locusta migratoria flight muscle troponin partially activates thin filament in a calcium-dependent manner. INSECT MOLECULAR BIOLOGY 2022; 31:346-355. [PMID: 35084070 DOI: 10.1111/imb.12763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/16/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
The troponin (Tn) complex, the sensor for Ca2+ to regulate contraction of striated muscle, is composed of three subunits, that is, TnT, TnI and TnC. Different isoforms of TnI and TnC are expressed in the thorax dorsal longitudinal muscle (flight muscle) and the hind leg extensor tibiae muscle (jump muscle) of the migratory locust, Locusta migratoria. The major Tn complexes in the flight muscle and the jump muscle are Tn-171 (TnT1/TnI7/TnC1) and Tn-153 (TnT1/TnI5/TnC3), respectively. Here, we prepared a number of recombinant Tn complexes and the reconstituted thin filaments, and investigated their regulation on thin filament. Although both Tn-171 and Tn-153 regulate thin filament in a Ca2+ -dependent manner, the extent of Ca2+ activation mediated by Tn-171 was significantly lower than that by Tn-153. We demonstrated that TnC1 and TnC3, rather than TnI5 and TnI7, are responsible for the different levels of the thin filament activation. Mutagenesis of TnC1 and TnC3 shows that the low level of TnC1-mediated thin filament activation can be attributed to the noncanonical residue Leu60 in the EF-hand-II of TnC1. We therefore propose that, in addition to Ca2+ , other regulatory mechanism(s) is required for the full activation of locust flight muscle.
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Affiliation(s)
- Hui-Fang Liang
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiang-Dong Li
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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6
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Shi Y, Bethea JP, Hetzel-Ebben HL, Landim-Vieira M, Mayper RJ, Williams RL, Kessler LE, Ruiz AM, Gargiulo K, Rose JSM, Platt G, Pinto JR, Washburn BK, Chase PB. Mandibular muscle troponin of the Florida carpenter ant Camponotus floridanus: extending our insights into invertebrate Ca 2+ regulation. J Muscle Res Cell Motil 2021; 42:399-417. [PMID: 34255253 DOI: 10.1007/s10974-021-09606-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/07/2021] [Indexed: 12/18/2022]
Abstract
Ants use their mandibles for a variety of functions and behaviors. We investigated mandibular muscle structure and function from major workers of the Florida carpenter ant Camponotus floridanus: force-pCa relation and velocity of unloaded shortening of single, permeabilized fibres, primary sequences of troponin subunits (TnC, TnI and TnT) from a mandibular muscle cDNA library, and muscle fibre ultrastructure. From the mechanical measurements, we found Ca2+-sensitivity of isometric force was markedly shifted rightward compared with vertebrate striated muscle. From the troponin sequence results, we identified features that could explain the rightward shift of Ca2+-activation: the N-helix of TnC is effectively absent and three of the four EF-hands of TnC (sites I, II and III) do not adhere to canonical sequence rules for divalent cation binding; two alternatively spliced isoforms of TnI were identified with the alternatively spliced exon occurring in the region of the IT-arm α-helical coiled-coil, and the N-terminal extension of TnI may be involved in modulation of regulation, as in mammalian cardiac muscle; and TnT has a Glu-rich C-terminus. In addition, a structural homology model was built of C. floridanus troponin on the thin filament. From analysis of electron micrographs, we found thick filaments are almost as long as the 6.8 μm sarcomeres, have diameter of ~ 16 nm, and typical center-to-center spacing of ~ 46 nm. These results have implications for the mechanisms by which mandibular muscle fibres perform such a variety of functions, and how the structure of the troponin complex aids in these tasks.
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Affiliation(s)
- Yun Shi
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Julia P Bethea
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Hannah L Hetzel-Ebben
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Ross J Mayper
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Regan L Williams
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Lauren E Kessler
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Amanda M Ruiz
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Kathryn Gargiulo
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Jennifer S M Rose
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Grayson Platt
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Brian K Washburn
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA. .,Department of Biological Science, Florida State University, Biology Unit One, Box 3064370, Tallahassee, FL, 32306-4370, USA.
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7
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Liang HF, Li J, Li XD. Identification and characterization of troponin genes in Locusta migratoria. INSECT MOLECULAR BIOLOGY 2020; 29:391-403. [PMID: 32338426 DOI: 10.1111/imb.12644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/12/2019] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Troponin complex comprises three subunits, namely troponin C (TpnC), troponin I (TpnI) and troponin T (TpnT), and regulates the contraction of striated muscle. We found that the locust Locusta migratoria genome has one TpnT gene (LmTpnT), one TpnI gene (LmTpnI) and three TpnC genes (LmTpnC1, LmTpnC2 and LmTpnC3). Through alternative splicing, LmTpnT and LmTpnI potentially encode two and eight isoforms, respectively. The flight muscle and the jump muscle of L. migratoria express an identical LmTpnT isoform, but different LmTpnC isoforms and LmTpnI isoforms. LmTpnC2 and LmTpnC3 both contain highly conserved residues essential for calcium binding in the EF-hand II and IV, thus belonging two-site isoform. LmTpnC1 contains non-conserved substitutions in the EF-hand II and all highly conserved residues for calcium binding in the EF-hand IV. Mutagenesis and tyrosine fluorescence spectroscopic analysis show that both the EF-hand II and IV of LmTpnC1 can serve as calcium-binding site. Therefore, all three LmTpnC isoforms belong to two-site isoform. This is in contrast to the situation in the insect with asynchronous flight muscle, which expresses both one-site isoform and two-site isoform of TpnC. Those results suggest that the origination of insect asynchronous flight muscle is associated with the emergence of one-site isoform of TpnC.
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Affiliation(s)
- H-F Liang
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - J Li
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - X-D Li
- State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Szikora S, Gajdos T, Novák T, Farkas D, Földi I, Lenart P, Erdélyi M, Mihály J. Nanoscopy reveals the layered organization of the sarcomeric H-zone and I-band complexes. J Cell Biol 2020; 219:132617. [PMID: 31816054 PMCID: PMC7039190 DOI: 10.1083/jcb.201907026] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/04/2019] [Accepted: 10/22/2019] [Indexed: 01/18/2023] Open
Abstract
Sarcomeres are extremely highly ordered macromolecular assemblies where structural organization is intimately linked to their functionality as contractile units. Although the structural basis of actin and Myosin interaction is revealed at a quasiatomic resolution, much less is known about the molecular organization of the I-band and H-zone. We report the development of a powerful nanoscopic approach, combined with a structure-averaging algorithm, that allowed us to determine the position of 27 sarcomeric proteins in Drosophila melanogaster flight muscles with a quasimolecular, ∼5- to 10-nm localization precision. With this protein localization atlas and template-based protein structure modeling, we have assembled refined I-band and H-zone models with unparalleled scope and resolution. In addition, we found that actin regulatory proteins of the H-zone are organized into two distinct layers, suggesting that the major place of thin filament assembly is an M-line-centered narrow domain where short actin oligomers can form and subsequently anneal to the pointed end.
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Affiliation(s)
- Szilárd Szikora
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Tamás Gajdos
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Tibor Novák
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Dávid Farkas
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - István Földi
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Peter Lenart
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Miklós Erdélyi
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - József Mihály
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
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9
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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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10
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Zhao Y, Zheng K, Zhu F. Molecular characterization of troponin C (TnC) in Scylla paramamosain and its role in white spot syndrome virus and Vibrio alginolyticus infection. FISH & SHELLFISH IMMUNOLOGY 2020; 98:522-533. [PMID: 31911290 DOI: 10.1016/j.fsi.2020.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/18/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Troponin C (TnC) is one member of the EF-hand superfamily. In many species, this gene had been identified and related functions had been elucidated. The TnC gene was still blank in the Scylla paramamosain. We obtained the TnC gene for the first time in the S. paramamosain. And we systematically analyzed the possible role of this gene in the innate immunity of S. paramamosain while infected with white spot syndrome virus (WSSV) or Vibrio alginolyticus. The full-length 1427 bp sequence of TnC contains a 453 bp open reading frame (ORF) for encoding a 151 amino acid protein. Detection of tissue specificity of gene expression showed that the TnC was primarily expressed in muscle tissue. The expression of TnC was successfully inhibited by RNA interference technology, and several immune genes were affected. The activity of phenoloxidase and superoxide dismutase increased, and the total hemocytes counts increased after RNAi of TnC. It was found that after infection with V. alginolyticus and WSSV, the expression of TnC in hemocytes decreased. Infected with V. alginolyticus and WSSV, the cumulative mortality and apoptotic rate of hemocytes increased after silencing the TnC gene. Our results indicate that TnC takes participate in the innate immunity of S. paramamosain and may plays a different role in the antiviral and antibacterial immune response.
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Affiliation(s)
- Yuebo Zhao
- Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, College of Animal Science and Technology, College of Veterinary Medicine, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Kaini Zheng
- Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, College of Animal Science and Technology, College of Veterinary Medicine, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China
| | - Fei Zhu
- Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, College of Animal Science and Technology, College of Veterinary Medicine, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
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11
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Lan H, Hong X, Huang R, Lin X, Li Q, Li K, Zhou T. RNA interference-mediated knockdown and virus-induced suppression of Troponin C gene adversely affect the behavior or fitness of the green rice leafhopper, Nephotettix cincticeps. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2018; 97:e21438. [PMID: 29193300 DOI: 10.1002/arch.21438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The green rice leafhopper, Nephotettix cincticeps, is a major rice pest in Southeast Asia and Southern China. Novel control strategies must be explored to control the rice pest. Behavior or fitness regulation of insect by modulating the Troponin C (TnC) may be a novel strategy in the comprehensive management of the insect pest. However, characterizations and functions of TnC, especially regarding effect of its RNA interference-mediated gene knockdown on the behavior or fitness of N. cincticeps remain unknown. Here, we successfully cloned and characterized TnC gene from N. cincticeps (Nc-TnC). We demonstrated that Nc-TnC ubiquitously transcribed at all development stages and special tissues in adult insects, with relative higher levels at the adult stage and in the intestinal canal. Microinjection- or oral membrane feeding-based transient knockdown of Nc-TnC adversely affected the performance or fitness, such as the decreased survival, feeding capacity, weight, and fecundity of N. cincticeps. Furthermore, we revealed that the expression of Nc-TnC was suppressed by its interaction with rice dwarf virus-encoded nonstructural protein 10, which ultimately affected detrimentally the corresponding parameters of the performance or fitness of N. cincticeps. In conclusion, our data deepen understanding of Nc-TnC functions during the development of and viral infection in N. cincticeps. It imply Nc-TnC may serve as a potential target for N. cincticeps control in future.
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Affiliation(s)
- Hanhong Lan
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Xiaojing Hong
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Ranran Huang
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Xin Lin
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Qinghuang Li
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Kaihui Li
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
| | - Tao Zhou
- School of Biological Sciences and Biotechnology, Minnan Normal University, Zhangzhou, PR China
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12
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Glasheen BM, Eldred CC, Sullivan LC, Zhao C, Reedy MK, Edwards RJ, Swank DM. Stretch activation properties of Drosophila and Lethocerus indirect flight muscle suggest similar calcium-dependent mechanisms. Am J Physiol Cell Physiol 2017; 313:C621-C631. [PMID: 28835434 DOI: 10.1152/ajpcell.00110.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Muscle stretch activation (SA) is critical for optimal cardiac and insect indirect flight muscle (IFM) power generation. The SA mechanism has been investigated for decades with many theories proposed, but none proven. One reason for the slow progress could be that multiple SA mechanisms may have evolved in multiple species or muscle types. Laboratories studying IFM SA in the same or different species have reported differing SA functional properties which would, if true, suggest divergent mechanisms. However, these conflicting results might be due to different experimental methodologies. Thus, we directly compared SA characteristics of IFMs from two SA model systems, Drosophila and Lethocerus, using two different fiber bathing solutions. Compared with Drosophila IFM, Lethocerus IFM isometric tension is 10- or 17-fold higher and SA tension was 5- or 10-fold higher, depending on the bathing solution. However, the rate of SA tension generation was 9-fold faster for Drosophila IFM. The inverse differences between rate and tension in the two species causes maximum power output to be similar, where Drosophila power is optimized in the bathing solution that favors faster muscle kinetics and Lethocerus in the solution that favors greater tension generation. We found that isometric tension and SA tension increased with calcium concentration for both species in both solutions, reaching a maximum plateau around pCa 5.0. Our results favor a similar mechanism for both species, perhaps involving a troponin complex that does not fully calcium activate the thin filament thus leaving room for further tension generation by SA.
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Affiliation(s)
- Bernadette M Glasheen
- Department of Biological Sciences, Biomedical Engineering, & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York
| | - Catherine C Eldred
- Department of Biological Sciences, Biomedical Engineering, & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York
| | - Leah C Sullivan
- Department of Biological Sciences, Biomedical Engineering, & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York
| | - Cuiping Zhao
- Department of Biological Sciences, Biomedical Engineering, & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York
| | - Michael K Reedy
- Department of Cell Biology, Duke University , Durham North Carolina
| | - Robert J Edwards
- Department of Cell Biology, Duke University , Durham North Carolina
| | - Douglas M Swank
- Department of Biological Sciences, Biomedical Engineering, & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York
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13
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Chechenova MB, Maes S, Oas ST, Nelson C, Kiani KG, Bryantsev AL, Cripps RM. Functional redundancy and nonredundancy between two Troponin C isoforms in Drosophila adult muscles. Mol Biol Cell 2017; 28:760-770. [PMID: 28077621 PMCID: PMC5349783 DOI: 10.1091/mbc.e16-07-0498] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 11/18/2022] Open
Abstract
Knockout of either of two Drosophila Troponin C genes that are expressed in either the flight muscle or the jump muscle resulted in expansion of transcription of its paralogue into the affected muscle. Although either isoform can support normal jumping, only the flight isoform can support flight. We investigated the functional overlap of two muscle Troponin C (TpnC) genes that are expressed in the adult fruit fly, Drosophila melanogaster: TpnC4 is predominantly expressed in the indirect flight muscles (IFMs), whereas TpnC41C is the main isoform in the tergal depressor of the trochanter muscle (TDT; jump muscle). Using CRISPR/Cas9, we created a transgenic line with a homozygous deletion of TpnC41C and compared its phenotype to a line lacking functional TpnC4. We found that the removal of either of these genes leads to expression of the other isoform in both muscle types. The switching between isoforms occurs at the transcriptional level and involves minimal enhancers located upstream of the transcription start points of each gene. Functionally, the two TpnC isoforms were not equal. Although ectopic TpnC4 in TDT muscles was able to maintain jumping ability, TpnC41C in IFMs could not effectively support flying. Simultaneous functional disruption of both TpnC genes resulted in jump-defective and flightless phenotypes of the survivors, as well as abnormal sarcomere organization. These results indicated that TpnC is required for myofibril assembly, and that there is functional specialization among TpnC isoforms in Drosophila.
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Affiliation(s)
- Maria B Chechenova
- Department of Biology, University of New Mexico, Albuquerque, NM 87131.,Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144
| | - Sara Maes
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Sandy T Oas
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Cloyce Nelson
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Kaveh G Kiani
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144
| | - Anton L Bryantsev
- Department of Biology, University of New Mexico, Albuquerque, NM 87131.,Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144
| | - Richard M Cripps
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
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14
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Zhang T, He K, Wang Z. Transcriptome Comparison Analysis of Ostrinia furnacalis in Four Developmental Stages. Sci Rep 2016; 6:35008. [PMID: 27713521 PMCID: PMC5054526 DOI: 10.1038/srep35008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/22/2016] [Indexed: 11/24/2022] Open
Abstract
The Asian corn borer, Ostrinia furnacalis, is one of the most destructive pests of maize and causes huge losses in maize yield each year. In order to characterize the different developmental stages, a high-throughput sequencing platform was employed to perform de novo transcriptome assembly and gene expression analysis for the egg, larva, pupa and adult stages. Approximately 185 million reads were obtained, trimmed, and assembled into 42,638 unigenes with an average length of 801.94 bp and an N50 length of 1,152 bp. These unigene sequences were annotated and classified by performing Gene Ontology (GO), Cluster of Orthologous Groups (KOG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional classifications. Comparison of the gene expression profiles of the two transitional stages revealed dramatic differences. Some differentially expressed genes are associated with digestion, cuticularization olfactory recognition and wing formation as well as growth and development. In total, 12 putative insect development-related genes were identified. Real-time quantitative PCR (RT-qPCR) results and sequencing based on relative expression levels of randomly selected genes confirmed these expression patterns. These data represent the most comprehensive transcriptomic resource currently available for O. furnacalis and will facilitate the study of developmental pathways, cuticularization, wing formation and olfactory recognition.
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Affiliation(s)
- Tiantao Zhang
- State Key Laboratory for the Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Beijing 100193, China
| | - Kanglai He
- State Key Laboratory for the Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Beijing 100193, China
| | - Zhenying Wang
- State Key Laboratory for the Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 West Yuanmingyuan Road, Beijing 100193, China
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15
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Adame V, Chapapas H, Cisneros M, Deaton C, Deichmann S, Gadek C, Lovato TL, Chechenova MB, Guerin P, Cripps RM. An undergraduate laboratory class using CRISPR/Cas9 technology to mutate drosophila genes. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 44:263-75. [PMID: 27009801 PMCID: PMC5377917 DOI: 10.1002/bmb.20950] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 10/26/2015] [Accepted: 12/08/2015] [Indexed: 05/25/2023]
Abstract
CRISPR/Cas9 genome editing technology is used in the manipulation of genome sequences and gene expression. Because of the ease and rapidity with which genes can be mutated using CRISPR/Cas9, we sought to determine if a single-semester undergraduate class could be successfully taught, wherein students isolate mutants for specific genes using CRISPR/Cas9. Six students were each assigned a single Drosophila gene, for which no mutants currently exist. Each student designed and created plasmids to encode single guide RNAs that target their selected gene; injected the plasmids into Cas9-expressing embryos, in order to delete the selected gene; carried out a three-generation cross to test for germline transmission of a mutated allele and generate a stable stock of the mutant; and characterized the mutant alleles by PCR and sequencing. Three genes out of six were successfully mutated. Pre- and post- survey evaluations of the students in the class revealed that student attitudes towards their research competencies increased, although the changes were not statistically significant. We conclude that it is feasible to develop a laboratory genome editing class, to provide effective laboratory training to undergraduate students, and to generate mutant lines for use by the broader scientific community. © 2016 by The International Union of Biochemistry and Molecular Biology, 44:263-275, 2016.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Paul Guerin
- Institute for Social Research, University of New Mexico, Albuquerque, NM 87131, USA
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16
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Chechenova MB, Maes S, Cripps RM. Expression of the Troponin C at 41C Gene in Adult Drosophila Tubular Muscles Depends upon Both Positive and Negative Regulatory Inputs. PLoS One 2015; 10:e0144615. [PMID: 26641463 PMCID: PMC4671713 DOI: 10.1371/journal.pone.0144615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/20/2015] [Indexed: 12/05/2022] Open
Abstract
Most animals express multiple isoforms of structural muscle proteins to produce tissues with different physiological properties. In Drosophila, the adult muscles include tubular-type muscles and the fibrillar indirect flight muscles. Regulatory processes specifying tubular muscle fate remain incompletely understood, therefore we chose to analyze the transcriptional regulation of TpnC41C, a Troponin C gene expressed in the tubular jump muscles, but not in the fibrillar flight muscles. We identified a 300-bp promoter fragment of TpnC41C sufficient for the fiber-specific reporter expression. Through an analysis of this regulatory element, we identified two sites necessary for the activation of the enhancer. Mutations in each of these sites resulted in 70% reduction of enhancer activity. One site was characterized as a binding site for Myocyte Enhancer Factor-2. In addition, we identified a repressive element that prevents activation of the enhancer in other muscle fiber types. Mutation of this site increased jump muscle-specific expression of the reporter, but more importantly reporter expression expanded into the indirect flight muscles. Our findings demonstrate that expression of the TpnC41C gene in jump muscles requires integration of multiple positive and negative transcriptional inputs. Identification of the transcriptional regulators binding the cis-elements that we identified will reveal the regulatory pathways controlling muscle fiber differentiation.
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Affiliation(s)
- Maria B Chechenova
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, United States of America
| | - Sara Maes
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, United States of America
| | - Richard M Cripps
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, United States of America
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17
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Ayme-Southgate A, Feldman S, Fulmer D. Myofilament proteins in the synchronous flight muscles of Manduca sexta show both similarities and differences to Drosophila melanogaster. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 62:174-182. [PMID: 25797474 DOI: 10.1016/j.ibmb.2015.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 01/26/2015] [Accepted: 02/17/2015] [Indexed: 06/04/2023]
Abstract
Insect flight muscles have been classified as either synchronous or asynchronous based on the coupling between excitation and contraction. In the moth Manduca sexta, the flight muscles are synchronous and do not display stretch activation, which is a property of asynchronous muscles. We annotated the M. sexta genes encoding the major myofibrillar proteins and analyzed their isoform pattern and expression. Comparison with the homologous genes in Drosophila melanogaster indicates both difference and similarities. For proteins such as myosin heavy chain, tropomyosin, and troponin I the availability and number of potential variants generated by alternative spicing is mostly conserved between the two insects. The exon usage associated with flight muscles indicates that some exon sets are similarly used in the two insects, whereas others diverge. For actin the number of individual genes is different and there is no evidence for a flight muscle specific isoform. In contrast for troponin C, the number of genes is similar, as well as the isoform composition in flight muscles despite the different calcium regulation. Both troponin I and tropomyosin can include COOH-terminal hydrophobic extensions similar to tropomyosinH and troponinH found in D. melanogaster and the honeybee respectively.
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Affiliation(s)
| | - Samuel Feldman
- Department of Biology, College of Charleston, Charleston, SC, USA
| | - Diana Fulmer
- Department of Biology, College of Charleston, Charleston, SC, USA
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18
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Abstract
Troponin proteins in cooperative interaction with tropomyosin are responsible for controlling the contraction of the striated muscles in response to changes in the intracellular calcium concentration. Contractility of the muscle is determined by the constituent protein isoforms, and the isoforms can switch over from one form to another depending on physiological demands and pathological conditions. In Drosophila, amajority of themyofibrillar proteins in the indirect flight muscles (IFMs) undergo post-transcriptional and post-translational isoform changes during pupal to adult metamorphosis to meet the high energy and mechanical demands of flight. Using a newly generated Gal4 strain (UH3-Gal4) which is expressed exclusively in the IFMs, during later stages of development, we have looked at the developmental and functional importance of each of the troponin subunits (troponin-I, troponin-T and troponin-C) and their isoforms. We show that all the troponin subunits are required for normal myofibril assembly and flight, except for the troponin-C isoform 1 (TnC1). Moreover, rescue experiments conducted with troponin-I embryonic isoform in the IFMs, where flies were rendered flightless, show developmental and functional differences of TnI isoforms and importance of maintaining the right isoform.
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19
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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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20
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The roles of troponin C isoforms in the mechanical function of Drosophila indirect flight muscle. J Muscle Res Cell Motil 2014; 35:211-23. [PMID: 25134799 DOI: 10.1007/s10974-014-9387-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/29/2014] [Indexed: 10/24/2022]
Abstract
Stretch activation (SA) is a fundamental property of all muscle types that increases power output and efficiency, yet its mechanism is unknown. Recently, studies have implicated troponin isoforms as important in the SA mechanism. The highly stretch-activated Drosophila IFMs express two isoforms of the Ca(2+)-binding subunit of troponin (TnC). TnC1 (TnC-F2 in Lethocerus IFM) has two calcium binding sites, while an unusual isoform, TnC4 (TnC-F1 in Lethocerus IFM), has only one binding site. We investigated the roles of these two TnC isoforms in Drosophila IFM by targeting RNAi to each isoform. IFMs with TnC4 expression (normally ~90% of total TnC) replaced by TnC1 did not generate isometric tension, power or display SA. However, TnC4 knockdown resulted in sarcomere ultrastructure disarray, which could explain the lack of mechanical function and thus make interpretation of the influence of TnC4 on SA difficult. Elimination of TnC1 expression (normally ~10% of total TnC) by RNAi resulted in normal muscle structure. In these IFMs, fiber power generation, isometric tension, stretch-activated force and calcium sensitivity were statistically identical to wild type. When TnC1 RNAi was driven by an IFM specific driver, there was no decrease in flight ability or wing beat frequency, which supports our mechanical findings suggesting that TnC1 is not essential for the mechanical function of Drosophila IFM. This finding contrasts with previous work in Lethocerus IFM showing TnC1 is essential for maximum isometric force generation. We propose that differences in TnC1 function in Lethocerus and Drosophila contribute to the ~40-fold difference in IFM isometric tension generated between these species.
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21
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Chakravorty S, Vu H, Foelber V, Vigoreaux JO. Mutations of the Drosophila myosin regulatory light chain affect courtship song and reduce reproductive success. PLoS One 2014; 9:e90077. [PMID: 24587213 PMCID: PMC3935995 DOI: 10.1371/journal.pone.0090077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 01/28/2014] [Indexed: 11/18/2022] Open
Abstract
The Drosophila indirect flight muscles (IFM) rely on an enhanced stretch-activation response to generate high power output for flight. The IFM is neurally activated during the male courtship song, but its role, if any, in generating the small amplitude wing vibrations that produce the song is not known. Here, we examined the courtship song properties and mating behavior of three mutant strains of the myosin regulatory light chain (DMLC2) that are known to affect IFM contractile properties and impair flight: (i) Dmlc2Δ2–46 (Ext), an N-terminal extension truncation; (ii) Dmlc2S66A,S67A (Phos), a disruption of two MLC kinase phosphorylation sites; and (iii) Dmlc2Δ2–46;S66A,S67A (Dual), expressing both mutations. Our results show that the Dmlc2 gene is pleiotropic and that mutations that have a profound effect on flight mechanics (Phos and Dual) have minimal effects on courtship song. None of the mutations affect interpulse interval (IPI), a determinant of species-specific song, and intrapulse frequency (IPF) compared to Control (Dmlc2+ rescued null strain). However, abnormalities in the sine song (increased frequency) and the pulse song (increased cycles per pulse and pulse length) evident in Ext males are not apparent in Dual males suggesting that Ext and Phos interact differently in song and flight mechanics, given their known additive effect on the latter. All three mutant males produce a less vigorous pulse song and exhibit impaired mating behavior compared to Control males. As a result, females are less receptive to Ext, Phos, and Dual males when a Control male is present. These results open the possibility that DMLC2, and perhaps contractile protein genes in general, are partly under sexual selection. That mutations in DMLC2 manifest differently in song and flight suggest that this protein fulfills different roles in song and flight and that stretch activation plays a smaller role in song production than in flight.
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Affiliation(s)
- Samya Chakravorty
- Department of Biology, The University of Vermont, Burlington, Vermont, United States of America
| | - Hien Vu
- Biochemistry Undergraduate Program, The University of Vermont, Burlington, Vermont, United States of America
| | - Veronica Foelber
- Biochemistry Undergraduate Program, The University of Vermont, Burlington, Vermont, United States of America
| | - Jim O. Vigoreaux
- Department of Biology, The University of Vermont, Burlington, Vermont, United States of America
- Department of Molecular Physiology and Biophysics, The University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
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22
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Wang Q, Newhard CS, Ramanath S, Sheppard D, Swank DM. An embryonic myosin converter domain influences Drosophila indirect flight muscle stretch activation, power generation and flight. ACTA ACUST UNITED AC 2013; 217:290-8. [PMID: 24115062 DOI: 10.1242/jeb.091769] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stretch activation (SA) is critical to the flight ability of insects powered by asynchronous, indirect flight muscles (IFMs). An essential muscle protein component for SA and power generation is myosin. Which structural domains of myosin are significant for setting SA properties and power generation levels is poorly understood. We made use of the transgenic techniques and unique single muscle myosin heavy chain gene of Drosophila to test the influence of the myosin converter domain on IFM SA and power generation. Replacing the endogenous converter with an embryonic version decreased SA tension and the rate of SA tension generation. The alterations in SA properties and myosin kinetics from the converter exchange caused power generation to drop to 10% of control fiber power when the optimal conditions for control fibers - 1% muscle length (ML) amplitude and 150 Hz oscillation frequency - were applied to fibers expressing the embryonic converter (IFI-EC). Optimizing conditions for IFI-EC fiber power production, by doubling ML amplitude and decreasing oscillation frequency by 60%, improved power output to 60% of optimized control fiber power. IFI-EC flies altered their aerodynamic flight characteristics to better match optimal fiber power generation conditions as wing beat frequency decreased and wing stroke amplitude increased. This enabled flight in spite of the drastic changes to fiber mechanical performance.
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Affiliation(s)
- Qian Wang
- Department of Biology and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
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23
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Ca2+-binding properties and regulatory roles of lobster troponin C sites II and IV. FEBS Lett 2013; 587:2612-6. [DOI: 10.1016/j.febslet.2013.06.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/14/2013] [Accepted: 06/21/2013] [Indexed: 11/18/2022]
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24
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Regulating the contraction of insect flight muscle. J Muscle Res Cell Motil 2011; 32:303-13. [PMID: 22105701 DOI: 10.1007/s10974-011-9278-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 11/11/2011] [Indexed: 10/15/2022]
Abstract
The rapid movement of the wings in small insects is powered by the indirect flight muscles. These muscles are capable of contracting at up to 1,000 Hz because they are activated mechanically by stretching. The mechanism is so efficient that it is also used in larger insects like the waterbug, Lethocerus. The oscillatory activity of the muscles occurs a low concentration of Ca(2+), which stays constant as the muscles contract and relax. Activation by stretch requires particular isoforms of tropomyosin and the troponin complex on the thin filament. We compare the tropomyosin and troponin of Lethocerus and Drosophila with that of vertebrates. The characteristics of the flight muscle regulatory proteins suggest ways in which stretch-activation works. There is evidence for bridges between troponin on thin filaments and myosin crossbridges on the thick filaments. Recent X-ray fibre diffraction results suggest that a pull on the bridges activates the thin filament by shifting tropomyosin from a blocking position on actin. The troponin bridges are likely to contain extended sequences of tropomyosin or troponin I (TnI). Flight muscle has two isoforms of TnC with different Ca(2+)-binding properties: F1 TnC is needed for stretch-activation and F2 TnC for isometric contractions. In this review, we describe the structural changes in both isoforms on binding Ca(2+) and TnI, and discuss how the steric model of muscle regulation can apply to insect flight muscle.
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25
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Husseneder C, McGregor C, Lang RP, Collier R, Delatte J. Transcriptome profiling of female alates and egg-laying queens of the Formosan subterranean termite. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2011; 7:14-27. [PMID: 22079412 DOI: 10.1016/j.cbd.2011.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 10/16/2022]
Abstract
Termites are known to have an extraordinary reproductive plasticity and capacity, but the underlying genetic patterns of termite reproductive biology are relatively understudied. The goal of this study was to identify genes for which expression levels differ between dealated precopulatory females (virgins) and egg-laying queens of the Formosan subterranean termite, Coptotermes formosanus Shiraki. We constructed a normalized polyphenic expressed sequence tag (EST) library that represents genomic material from most of the castes and life stages of the Formosan subterranean termite. Microarrays were designed using probes from this EST library and public genomic resources. Virgin females and queens were competitively hybridized to these microarrays and differentially expressed candidate genes were identified. Differential expression of eight genes was subsequently confirmed via reverse transcriptase quantitative PCR (RT-QPCR). When compared to virgins, queens had higher expression of genes coding for proteins related to immunity (gram negative binding protein), nutrition (e.g., termite-derived endo-beta-1,4-glucanase), protein storage, regulation of caste differentiation and reproduction (hexamerin, juvenile hormone binding protein). Queens also had higher transcript levels for genes involved in metabolism of xenobiotics, fat, and juvenile hormone (glutathione-S-transferase-like proteins, and cytochrome P450), among others. In particular, hexamerin, juvenile hormone binding protein, and a cytochrome P450 from the 4C subfamily are likely to be involved in initiating the inactive period during the reproductive cycle of the queen. Vice versa, virgins had higher expression than queens of genes related to respiration, probably due to recent flight activity, and several genes of unknown function.
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Affiliation(s)
- Claudia Husseneder
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA.
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26
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Martin SR, Avella G, Adrover M, de Nicola GF, Bullard B, Pastore A. Binding properties of the calcium-activated F2 isoform of Lethocerus troponin C. Biochemistry 2011; 50:1839-47. [PMID: 21250664 PMCID: PMC3057471 DOI: 10.1021/bi102076s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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While in most muscles contraction is triggered by calcium effluxes, insect flight muscles are also activated by mechanical stretch. We are interested in understanding the role that the troponin C protein, usually the calcium sensor, plays in stretch activation. In the flight muscles of Lethocerus, a giant water bug often used as a model system, there are two isoforms of TnC, F1 and F2, present in an approximately 10:1 ratio. F1 TnC is responsible for activating the muscle following a stretch, whereas F2 TnC produces a sustained contraction, the magnitude of which depends on the concentration of Ca2+ in the fiber. We have previously shown that F1 TnC binds only one Ca2+ ion in its C-terminal domain and that interaction with troponin H, the insect ortholog of troponin I, is insensitive to Ca2+. Here, we have studied the effect of Ca2+ and Mg2+ on the affinities of the interaction of F2 TnC with troponin H peptides. We show that the presence of two Ca2+ ions, one in each of the globular domains, increases the affinity for TnH by at least 1 order of magnitude. The N lobe has a lower affinity for Ca2+, but it is also sensitive to Mg2+. The C lobe is insensitive to Mg2+ as previously demonstrated by mutations of the individual EF-hands. The interaction with TnH seems also to have significant structural differences from that observed for the F1 TnC isoform. We discuss how our findings could account for stretch activation.
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Affiliation(s)
- Stephen R Martin
- National Institute for Medical Research, The Ridgeway, London NW71AA, U.K
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Cloning and tissue expression of eleven troponin-C isoforms in the American lobster, Homarus americanus. Comp Biochem Physiol B Biochem Mol Biol 2010; 157:88-101. [DOI: 10.1016/j.cbpb.2010.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 05/14/2010] [Accepted: 05/17/2010] [Indexed: 11/19/2022]
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Vikhorev PG, Vikhoreva NN, Cammarato A, Sparrow JC. In vitro motility of native thin filaments from Drosophila indirect flight muscles reveals that the held-up 2 TnI mutation affects calcium activation. J Muscle Res Cell Motil 2010; 31:171-9. [PMID: 20658179 DOI: 10.1007/s10974-010-9221-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 07/13/2010] [Indexed: 11/26/2022]
Abstract
A procedure for the isolation of regulated native thin filaments from the indirect flight muscles (IFM) of Drosophila melanogaster is described. These are the first striated invertebrate thin filaments to show Ca-regulated in vitro motility. Regulated native thin filaments from wild type and a troponin I mutant, held-up-2, were compared by in vitro motility assays that showed that the mutant troponin I caused activation of motility at pCa values higher than wild type. The held-up2 mutation, in the sole troponin I gene (wupA) in the Drosophila genome, is known to cause hypercontraction of the IFM and other muscles in vivo leading to their eventual destruction. The mutation causes substitution of alanine by valine at a homologous and completely conserved troponin I residue (A25) in the vertebrate skeletal muscle TnI isoform. The effects of the held-up 2 mutation on calcium activation of thin filament in vitro motility are discussed with respect to its effects on hypercontraction and dysfunction. Previous electron microscopy and 3-dimensional reconstruction studies showed that the tropomyosin of held-up 2 thin filaments occupies positions associated with the so-called 'closed' state, but independently of calcium concentration. This is discussed with respect to calcium dependent regulation of held-up-2 thin filaments in in vitro motility.
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Affiliation(s)
- P G Vikhorev
- Department of Biology, University of York, York YO10 5DD, UK
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29
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De Nicola GF, Martin S, Bullard B, Pastore A. Solution structure of the Apo C-terminal domain of the Lethocerus F1 troponin C isoform. Biochemistry 2010; 49:1719-26. [PMID: 20104876 PMCID: PMC3388720 DOI: 10.1021/bi902094w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/24/2010] [Indexed: 11/28/2022]
Abstract
Muscle contraction is activated by two distinct mechanisms. One depends on the calcium influx, and the other is calcium-independent and activated by mechanical stress. A prototypical example of stretch activation is observed in insect muscles. In Lethocerus, a model system ideally suited for studying stretch activation, the two mechanisms seem to be under the control of different isoforms of troponin C (TnC), F1 and F2, which are responsible for stretch and calcium-dependent regulation, respectively. We have previously shown that F1 TnC is a typical collapsed dumbbell EF-hand protein that accommodates one calcium ion in its fourth EF-hand. When calcium loaded, the C-terminal domain of F1 TnC is in an open conformation which allows binding to troponin I. We have determined the solution structure of the isolated F1 TnC C-terminal domain in the absence of calcium and have compared it together with its dynamical properties with those of the calcium-loaded form. The domain is folded also in the absence of calcium and is in a closed conformation. Binding of a single calcium is sufficient to induce a modest but clear closed-to-open conformational transition and releases the conformational entropy observed in the calcium-free form. These results provide the first example of a TnC domain in which the presence of only one calcium ion is sufficient to induce a closed-to-open transition and clarify the role of calcium in stretch activation.
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Affiliation(s)
- Gian Felice De Nicola
- Molecular Structure Division, National Institute for Medical Research, MRC, The Ridgeway, Mill Hill, London NW71AA, U.K
| | - Stephen Martin
- Molecular Structure Division, National Institute for Medical Research, MRC, The Ridgeway, Mill Hill, London NW71AA, U.K
| | - Belinda Bullard
- Department of Biology, University of York, York YO10 5DD, U.K
| | - Annalisa Pastore
- Molecular Structure Division, National Institute for Medical Research, MRC, The Ridgeway, Mill Hill, London NW71AA, U.K
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30
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Krzic U, Rybin V, Leonard KR, Linke WA, Bullard B. Regulation of oscillatory contraction in insect flight muscle by troponin. J Mol Biol 2010; 397:110-8. [PMID: 20100491 DOI: 10.1016/j.jmb.2010.01.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/06/2010] [Accepted: 01/18/2010] [Indexed: 11/25/2022]
Abstract
Insect indirect flight muscle is activated by sinusoidal length change, which enables the muscle to work at high frequencies, and contracts isometrically in response to Ca(2+). Indirect flight muscle has two TnC isoforms: F1 binding a single Ca(2+) in the C-domain, and F2 binding Ca(2+) in the N- and C-domains. Fibres substituted with F1 produce delayed force in response to a single rapid stretch, and those with F2 produce isometric force in response to Ca(2+). We have studied the effect of TnC isoforms on oscillatory work. In native Lethocerus indicus fibres, oscillatory work was superimposed on a level of isometric force that depended on Ca(2+) concentration. Maximum work was produced at pCa 6.1; at higher concentrations, work decreased as isometric force increased. In fibres substituted with F1 alone, work continued to rise as Ca(2+) was increased up to pCa 4.7. Fibres substituted with various F1:F2 ratios produced maximal work at a ratio of 100:1 or 50:1; a higher proportion of F2 increased isometric force at the expense of oscillatory work. The F1:F2 ratio was 9.8:1 in native fibres, as measured by immunofluorescence, using isoform-specific antibodies. The small amount of F2 needed to restore work to levels obtained for the native fibre is likely to be due to the relative affinity of F1 and F2 for TnH, the Lethocerus homologue of TnI. Affinity of TnC isoforms for a TnI fragment of TnH was measured by isothermal titration calorimetry. The K(d) was 1.01 muM for F1 binding and 22.7 nM for F2. The higher affinity of F2 can be attributed to two TnH binding sites on F2 and a single site on F1. Stretch may be sensed by an extended C-terminal domain of TnH, resulting in reversible dissociation of the inhibitory sequence from actin during the oscillatory cycle.
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Affiliation(s)
- Uros Krzic
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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31
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Kowlessur D, Tobacman LS. Troponin regulatory function and dynamics revealed by H/D exchange-mass spectrometry. J Biol Chem 2009; 285:2686-94. [PMID: 19920153 DOI: 10.1074/jbc.m109.062349] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Muscle contraction is tightly regulated by Ca(2+) binding to the thin filament protein troponin. The mechanism of this regulation was investigated by detailed mapping of the dynamic properties of cardiac troponin using amide hydrogen exchange-mass spectrometry. Results were obtained in the presence of either saturation or non-saturation of the regulatory Ca(2+) binding site in the NH(2) domain of subunit TnC. Troponin was found to be highly dynamic, with 60% of amides exchanging H for D within seconds of exposure to D(2)O. In contrast, portions of the TnT-TnI coiled-coil exhibited high protection from exchange, despite 6 h in D(2)O. The data indicate that the most stable portion of the trimeric troponin complex is the coiled-coil. Regulatory site Ca(2+) binding altered dynamic properties (i.e. H/D exchange protection) locally, near the binding site and in the TnI switch helix that attaches to the Ca(2+)-saturated TnC NH(2) domain. More notably, Ca(2+) also altered the dynamic properties of other parts of troponin: the TnI inhibitory peptide region that binds to actin, the TnT-TnI coiled-coil, and the TnC COOH domain that contains the regulatory Ca(2+) sites in many invertebrate as opposed to vertebrate troponins. Mapping of these affected regions onto the troponin highly extended structure suggests that cardiac troponin switches between alternative sets of intramolecular interactions, similar to previous intermediate resolution x-ray data of skeletal muscle troponin.
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Affiliation(s)
- Devanand Kowlessur
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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32
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Electron microscopy and three-dimensional reconstruction of native thin filaments reveal species-specific differences in regulatory strand densities. Biochem Biophys Res Commun 2009; 391:193-7. [PMID: 19900412 DOI: 10.1016/j.bbrc.2009.11.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 11/05/2009] [Indexed: 11/24/2022]
Abstract
Throughout the animal kingdom striated muscle contraction is regulated by the thin filament troponin-tropomyosin complex. Homologous regulatory components are shared among vertebrate and arthropod muscles; however, unique protein extensions and/or components characterize the latter. The Troponin T (TnT) isoforms of Drosophila indirect flight and tarantula femur muscle for example contain distinct C-terminal extensions and are approximately 20% larger overall than their vertebrate counterpart. Using electron microscopy and three-dimensional helical reconstruction of native Drosophila, tarantula and frog muscle thin filaments we have identified species-specific differences in tropomyosin regulatory strand densities. The strands on the arthropod thin filaments were significantly larger in diameter than those from vertebrates, although not significantly different from each other. These findings reflect differences in the regulatory troponin-tropomyosin complex, which are likely due to the larger TnT molecules aligning and extending along much of the tropomyosin strands' length. Such an arrangement potentially alters the physical properties of the regulatory strands and may help establish contractile characteristics unique to certain arthropod muscles.
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33
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Ayme-Southgate AJ, Southgate RJ, Philipp RA, Sotka EE, Kramp C. The myofibrillar protein, projectin, is highly conserved across insect evolution except for its PEVK domain. J Mol Evol 2008; 67:653-69. [PMID: 18982379 PMCID: PMC2775928 DOI: 10.1007/s00239-008-9177-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 10/08/2008] [Indexed: 10/21/2022]
Abstract
All striated muscles respond to stretch by a delayed increase in tension. This physiological response, known as stretch activation, is, however, predominantly found in vertebrate cardiac muscle and insect asynchronous flight muscles. Stretch activation relies on an elastic third filament system composed of giant proteins known as titin in vertebrates or kettin and projectin in insects. The projectin insect protein functions jointly as a "scaffold and ruler" system during myofibril assembly and as an elastic protein during stretch activation. An evolutionary analysis of the projectin molecule could potentially provide insight into how distinct protein regions may have evolved in response to different evolutionary constraints. We mined candidate genes in representative insect species from Hemiptera to Diptera, from published and novel genome sequence data, and carried out a detailed molecular and phylogenetic analysis. The general domain organization of projectin is highly conserved, as are the protein sequences of its two repeated regions-the immunoglobulin type C and fibronectin type III domains. The conservation in structure and sequence is consistent with the proposed function of projectin as a scaffold and ruler. In contrast, the amino acid sequences of the elastic PEVK domains are noticeably divergent, although their length and overall unusual amino acid makeup are conserved. These patterns suggest that the PEVK region working as an unstructured domain can still maintain its dynamic, and even its three-dimensional, properties, without the need for strict amino acid conservation. Phylogenetic analysis of the projectin proteins also supports a reclassification of the Hymenoptera in relation to Diptera and Coleoptera.
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Affiliation(s)
- Agnes J Ayme-Southgate
- Department of Biology, College of Charleston, 66 George Street, Charleston, SC 29401, USA.
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Hooper SL, Hobbs KH, Thuma JB. Invertebrate muscles: thin and thick filament structure; molecular basis of contraction and its regulation, catch and asynchronous muscle. Prog Neurobiol 2008; 86:72-127. [PMID: 18616971 PMCID: PMC2650078 DOI: 10.1016/j.pneurobio.2008.06.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 05/08/2008] [Accepted: 06/12/2008] [Indexed: 11/26/2022]
Abstract
This is the second in a series of canonical reviews on invertebrate muscle. We cover here thin and thick filament structure, the molecular basis of force generation and its regulation, and two special properties of some invertebrate muscle, catch and asynchronous muscle. Invertebrate thin filaments resemble vertebrate thin filaments, although helix structure and tropomyosin arrangement show small differences. Invertebrate thick filaments, alternatively, are very different from vertebrate striated thick filaments and show great variation within invertebrates. Part of this diversity stems from variation in paramyosin content, which is greatly increased in very large diameter invertebrate thick filaments. Other of it arises from relatively small changes in filament backbone structure, which results in filaments with grossly similar myosin head placements (rotating crowns of heads every 14.5 nm) but large changes in detail (distances between heads in azimuthal registration varying from three to thousands of crowns). The lever arm basis of force generation is common to both vertebrates and invertebrates, and in some invertebrates this process is understood on the near atomic level. Invertebrate actomyosin is both thin (tropomyosin:troponin) and thick (primarily via direct Ca(++) binding to myosin) filament regulated, and most invertebrate muscles are dually regulated. These mechanisms are well understood on the molecular level, but the behavioral utility of dual regulation is less so. The phosphorylation state of the thick filament associated giant protein, twitchin, has been recently shown to be the molecular basis of catch. The molecular basis of the stretch activation underlying asynchronous muscle activity, however, remains unresolved.
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Affiliation(s)
- Scott L. Hooper
- Neuroscience Program Department of Biological Sciences Ohio University Athens, OH 45701 614 593-0679 (voice) 614 593-0687 (FAX)
| | - Kevin H. Hobbs
- Neuroscience Program Department of Biological Sciences Ohio University Athens, OH 45701 614 593-0679 (voice) 614 593-0687 (FAX)
| | - Jeffrey B. Thuma
- Neuroscience Program Department of Biological Sciences Ohio University Athens, OH 45701 614 593-0679 (voice) 614 593-0687 (FAX)
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Hutter S, Saminadin-Peter SS, Stephan W, Parsch J. Gene expression variation in African and European populations of Drosophila melanogaster. Genome Biol 2008; 9:R12. [PMID: 18208589 PMCID: PMC2395247 DOI: 10.1186/gb-2008-9-1-r12] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 01/09/2008] [Accepted: 01/21/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Differences in levels of gene expression among individuals are an important source of phenotypic variation within populations. Recent microarray studies have revealed that expression variation is abundant in many species, including Drosophila melanogaster. However, previous expression surveys in this species generally focused on a small number of laboratory strains established from derived populations. Thus, these studies were not ideal for population genetic analyses. RESULTS We surveyed gene expression variation in adult males of 16 D. melanogaster strains from two natural populations, including an ancestral African population and a derived European population. Levels of expression polymorphism were nearly equal in the two populations, but a higher number of differences was detected when comparing strains between populations. Expression variation was greatest for genes associated with few molecular functions or biological processes, as well as those expressed predominantly in males. Our analysis also identified genes that differed in expression level between the European and African populations, which may be candidates for adaptive regulatory evolution. Genes involved in flight musculature and fatty acid metabolism were over-represented in the list of candidates. CONCLUSION Overall, stabilizing selection appears to be the major force governing gene expression variation within populations. However, positive selection may be responsible for much of the between-population expression divergence. The nature of the genes identified to differ in expression between populations may reveal which traits were important for local adaptation to the European and African environments.
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Affiliation(s)
- Stephan Hutter
- Section of Evolutionary Biology, Department of Biology, University of Munich, Grosshaderner Strasse, Planegg-Martinsried 82152, Germany.
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36
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Chen J, Chen J, Gai Q, Lv Z, Wang D, Nie Z, Wang J, Wang X, Wu X, Zhang Y. Molecular characterization and immunohistochemical localization of a novel troponin C during silkworm development. Cell Tissue Res 2007; 331:725-38. [PMID: 18087728 DOI: 10.1007/s00441-007-0516-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 09/06/2007] [Indexed: 10/22/2022]
Abstract
We have cloned and sequenced a novel Bombyx mori gene that encodes a protein having a high degree of homology with other known troponin C (TnC) proteins. The amino acid sequence, DX[DN]X[DSG]X(6)E, a highly conserved putative Ca(2+) -binding motif found in loops within the globular domains of previously identified TnC proteins, is also present in BmTnC. We have expressed and purified to homogeneity a His-tagged BmTnC fusion protein having a molecular weight of approximately 21.6 kDa. We have used this purified fusion protein to produce polyclonal antibodies against BmTnC for Western blot analyses. These analyses have revealed that BmTnC is expressed in the larval head, the Malpighian tubule, the epidermis, the testis, and the gut, as has been confirmed by immunohistochemistry. In addition, real-time reverse transcription/polymerase chain reaction has shown that BmTnC mRNA levels differ substantially among these tissues. Our findings indicate that BmTnC is selectively expressed in the muscular tissues of the silkworm, including portions of the head, the Malpighian tubule, the body wall, and the gut.
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Affiliation(s)
- Jianqing Chen
- Institute of Biochemistry, Zhejiang Sci-Tech University, Xiasha Higher Education Zone, Hangzhou, China
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37
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Boussouf SE, Agianian B, Bullard B, Geeves MA. The regulation of myosin binding to actin filaments by Lethocerus troponin. J Mol Biol 2007; 373:587-98. [PMID: 17868693 PMCID: PMC2238177 DOI: 10.1016/j.jmb.2007.07.066] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Revised: 07/23/2007] [Accepted: 07/25/2007] [Indexed: 11/23/2022]
Abstract
Lethocerus indirect flight muscle has two isoforms of troponin C, TnC-F1 and F2, which are unusual in having only a single C-terminal calcium binding site (site IV, isoform F1) or one C-terminal and one N-terminal site (sites IV and II, isoform F2). We show here that thin filaments assembled from rabbit actin and Lethocerus tropomyosin (Tm) and troponin (Tn) regulate the binding of rabbit myosin to rabbit actin in much the same way as the mammalian regulatory proteins. The removal of calcium reduces the rate constant for S1 binding to regulated actin about threefold, independent of which TmTn is used. This is consistent with calcium removal causing the TmTn to occupy the B or blocked state to about 70% of the total. The mid point pCa for the switch differed for TnC-F1 and F2 (pCa 6.9 and 6.0, respectively) consistent with the reported calcium affinities for the two TnCs. Equilibrium titration of S1 binding to regulated actin filaments confirms calcium regulated binding of S1 to actin and shows that in the absence of calcium the three actin filaments (TnC-F1, TnC-F2 and mammalian control) are almost indistinguishable in terms of occupancy of the B and C states of the filament. In the presence of calcium TnC-F2 is very similar to the control with approximately 80% of the filament in the C-state and 10-15% in the fully on M-State while TnC-F1 has almost 50% in each of the C and M states. This higher occupancy of the M-state for TnC-F1, which occurs above pCa 6.9, is consistent with this isoform being involved in the calcium activation of stretch activation. However, it leaves unanswered how a C-terminal calcium binding site of TnC can activate the thin filament.
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Affiliation(s)
- Sabrina E Boussouf
- Protein Sciences Group, Department of Biosciences, University of Kent at Canterbury CT2 7NJ, UK
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38
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De Nicola G, Burkart C, Qiu F, Agianian B, Labeit S, Martin S, Bullard B, Pastore A. The Structure of Lethocerus Troponin C: Insights into the Mechanism of Stretch Activation in Muscles. Structure 2007; 15:813-24. [PMID: 17637342 DOI: 10.1016/j.str.2007.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 05/07/2007] [Accepted: 05/07/2007] [Indexed: 10/23/2022]
Abstract
To gain a molecular description of how muscles can be activated by mechanical stretch, we have solved the structure of the calcium-loaded F1 isoform of troponin C (TnC) from Lethocerus and characterized its interactions with troponin I (TnI). We show that the presence of only one calcium cation in the fourth EF hand motif is sufficient to induce an open conformation in the C-terminal lobe of F1 TnC, in contrast with what is observed in vertebrate muscle. This lobe interacts in a calcium-independent way both with the N terminus of TnI and, with lower affinity, with a region of TnI equivalent to the switch and inhibitory peptides of vertebrate muscles. Using both synthetic peptides and recombinant proteins, we show that the N lobe of F1 TnC is not engaged in interactions with TnI, excluding a regulatory role of this domain. These findings provide insights into mechanically stimulated muscle contraction.
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Affiliation(s)
- Gianfelice De Nicola
- Molecular Structure Division, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
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Nongthomba U, Ansari M, Thimmaiya D, Stark M, Sparrow J. Aberrant splicing of an alternative exon in the Drosophila troponin-T gene affects flight muscle development. Genetics 2007; 177:295-306. [PMID: 17603127 PMCID: PMC2013690 DOI: 10.1534/genetics.106.056812] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During myofibrillogenesis, many muscle structural proteins assemble to form the highly ordered contractile sarcomere. Mutations in these proteins can lead to dysfunctional muscle and various myopathies. We have analyzed the Drosophila melanogaster troponin T (TnT) up1 mutant that specifically affects the indirect flight muscles (IFM) to explore troponin function during myofibrillogenesis. The up1 muscles lack normal sarcomeres and contain "zebra bodies," a phenotypic feature of human nemaline myopathies. We show that the up(1) mutation causes defective splicing of a newly identified alternative TnT exon (10a) that encodes part of the TnT C terminus. This exon is used to generate a TnT isoform specific to the IFM and jump muscles, which during IFM development replaces the exon 10b isoform. Functional differences between the 10a and 10b TnT isoforms may be due to different potential phosphorylation sites, none of which correspond to known phosphorylation sites in human cardiac TnT. The absence of TnT mRNA in up1 IFM reduces mRNA levels of an IFM-specific troponin I (TnI) isoform, but not actin, tropomyosin, or troponin C, suggesting a mechanism controlling expression of TnT and TnI genes may exist that must be examined in the context of human myopathies caused by mutations of these thin filament proteins.
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Affiliation(s)
- Upendra Nongthomba
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
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40
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Gäde G, Simek P, Marco HG. Water scorpions (Heteroptera, Nepidae) and giant water bugs (Heteroptera, Belostomatidae): sources of new members of the adipokinetic hormone/red pigment-concentrating hormone family. Peptides 2007; 28:1359-67. [PMID: 17604877 DOI: 10.1016/j.peptides.2007.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 05/06/2007] [Accepted: 05/10/2007] [Indexed: 11/17/2022]
Abstract
Two novel octapeptide members of the AKH/RPCH family have been identified from the corpora cardiaca (CC) of two species of water bugs. The giant water bug Lethocerus indicus (family: Belostomatidae) contains a peptide code-named Letin-AKH with the sequence pGlu-Val-Asn-Phe-Ser-Pro-Tyr-Trp amide, and the water scorpion Nepa cinerea (family: Nepidae) has the peptide code-named Nepci-AKH with the sequence pGlu-Leu/Ile-Asn-Phe-Ser-Ser-Gly-Trp amide. The sequences were deduced from the multiple MS(N) electrospray mass data from crude CC extracts. Synthetic peptides were made and co-elution on reversed-phase high performance liquid chromatography (RP-HPLC) with the natural peptide from crude gland extract confirmed the accuracy of the deduced sequence for Letin-AKH and demonstrated that Nepci-AKH contains a Leu residue at position 2 and not an Ile residue. A previously characterized member of the AKH/RPCH family was identified in the stick water scorpion Ranatra linearis by mass spectrometry: Grybi-AKH (pGlu-Val-Asn-Phe-Ser-Thr-Gly-Trp amide) has the same mass (919 Da) as Nepci-AKH and differs in two positions from Nepci-AKH (residues 2 and 6). The apparent function of the peptides is to achieve lipid mobilization in the species under investigation; indications for this came from conspecific bioassays using the appropriate synthetic peptides for injecting into the insects. This function is very likely linked to dispersal flight metabolism of water bugs. Swimming activity in N. cinerea also results in an increase in lipid concentration in the hemolymph.
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Affiliation(s)
- Gerd Gäde
- Zoology Department, University of Cape Town, Private Bag, ZA-7701 Rondebosch, South Africa.
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Mateos J, Herranz R, Domingo A, Sparrow J, Marco R. The structural role of high molecular weight tropomyosins in dipteran indirect flight muscle and the effect of phosphorylation. J Muscle Res Cell Motil 2006; 27:189-201. [PMID: 16752200 DOI: 10.1007/s10974-005-9044-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Accepted: 10/18/2005] [Indexed: 10/24/2022]
Abstract
In Drosophila melanogaster two high molecular weight tropomyosin isoforms, historically named heavy troponins (TnH-33 and TnH-34), are encoded by the Tm1 tropomyosin gene. They are specifically expressed in the indirect flight muscles (IFM). Their N-termini are conventional and complete tropomyosin sequences, but their C-termini consist of different IFM-specific domains that are rich in proline, alanine, glycine and glutamate. The evidence indicates that in Diptera these IFM-specific isoforms are conserved and are not troponins, but heavy tropomyosins (TmH). We report here that they are post-translationally modified by several phosphorylations in their C-termini in mature flies, but not in recently emerged flies that are incapable of flight. From stoichiometric measurements of thin filament proteins and interactions of the TmH isoforms with the standard Drosophila IFM tropomyosin isoform (protein 129), we propose that the TmH N-termini are integrated into the thin filament structural unit as tropomyosin dimers. The phosphorylated C-termini remain unlocated and may be important in IFM stretch-activation. Comparison of the Tm1 and Tm2 gene sequences shows a complete conservation of gene organisation in other Drosophilidae, such as Drosophila pseudoobscura, while in Anopheles gambiae only one exon encodes a single C-terminal domain, though overall gene organization is maintained. Interestingly, in Apis mellifera (hymenopteran), while most of the Tm1 and Tm2 gene features are conserved, the gene lacks any C-terminal exons. Instead these sequences are found at the 3' end of the troponin I gene. In this insect order, as in Lethocerus (hemipteran), the original designation of troponin H (TnH) should be retained. We discuss whether the insertion of the IFM-specific pro-ala-gly-glu-rich domain into the tropomyosin or troponin I genes in different insect orders may be related to proposals that the IFM stretch activation mechanism has evolved independently several times in higher insects.
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Affiliation(s)
- Jesús Mateos
- Departamento de Bioquímica (UAM) e Instituto Alberto Sols (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain.
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Herranz R, Mateos J, Mas JA, García-Zaragoza E, Cervera M, Marco R. The Coevolution of Insect Muscle TpnT and TpnI Gene Isoforms. Mol Biol Evol 2005; 22:2231-42. [PMID: 16049195 DOI: 10.1093/molbev/msi223] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In bilaterians, the main regulator of muscle contraction is the troponin (Tpn) complex, comprising three closely interacting subunits (C, T, and I). To understand how evolutionary forces drive molecular change in protein complexes, we have compared the gene structures and expression patterns of Tpn genes in insects. In this class, while TpnC is encoded by multiple genes, TpnT and TpnI are encoded by single genes. Their isoform expression pattern is highly conserved within the Drosophilidae, and single orthologous genes were identified in the sequenced genomes of Drosophila pseudoobscura, Anopheles gambiae, and Apis mellifera. Apis expression patterns also support the equivalence of their exon organization throughout holometabolous insects. All TpnT genes include a previously unidentified indirect flight muscle (IFM)-specific exon (10A) that has evolved an expression pattern similar to that of exon 9 in TpnI. Thus, expression patterns, sequence evolution trends, and structural data indicate that Tpn genes and their isoforms have coevolved, building species- and muscle-specific troponin complexes. Furthermore, a clear case can be made for independent evolution of the IFM-specific isoforms containing alanine/proline-rich sequences. Dipteran genomes contain one tropomyosin gene that encodes one or two high-molecular weight isoforms (TmH) incorporating APPAEGA-rich sequences, specifically expressed in IFM. Corresponding exons do not exist in the Apis tropomyosin gene, but equivalent sequences occur in a high-molecular weight Apis IFM-specific TpnI isoform (TnH). Overall, our approach to comparatively analyze supramolecular complexes reveals coevolutionary trends not only in gene families but in isoforms generated by alternative splicing.
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Affiliation(s)
- Raúl Herranz
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo 4, 28029 Madrid, Spain
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Abstract
This is the first of a projected series of canonic reviews covering all invertebrate muscle literature prior to 2005 and covers muscle genes and proteins except those involved in excitation-contraction coupling (e.g., the ryanodine receptor) and those forming ligand- and voltage-dependent channels. Two themes are of primary importance. The first is the evolutionary antiquity of muscle proteins. Actin, myosin, and tropomyosin (at least, the presence of other muscle proteins in these organisms has not been examined) exist in muscle-like cells in Radiata, and almost all muscle proteins are present across Bilateria, implying that the first Bilaterian had a complete, or near-complete, complement of present-day muscle proteins. The second is the extraordinary diversity of protein isoforms and genetic mechanisms for producing them. This rich diversity suggests that studying invertebrate muscle proteins and genes can be usefully applied to resolve phylogenetic relationships and to understand protein assembly coevolution. Fully achieving these goals, however, will require examination of a much broader range of species than has been heretofore performed.
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Affiliation(s)
- Scott L Hooper
- Neuroscience Program, Department of Biological Sciences, Irvine Hall, Ohio University, Athens, Ohio 45701, USA.
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Qiu F, Brendel S, Cunha PMF, Astola N, Song B, Furlong EEM, Leonard KR, Bullard B. Myofilin, a protein in the thick filaments of insect muscle. J Cell Sci 2005; 118:1527-36. [PMID: 15769842 DOI: 10.1242/jcs.02281] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thick filaments in striated muscle are myosin polymers with a length and diameter that depend on the fibre type. In invertebrates, the length of the thick filaments varies widely in different muscles and additional proteins control filament assembly. Thick filaments in asynchronous insect flight muscle have an extremely regular structure, which is likely to be essential for the oscillatory contraction of these muscles. The factors controlling the assembly of thick filaments in insect flight muscle are not known. We previously identified a thick filament core protein, zeelin 1, in Lethocerus flight and non-flight muscles. This has been sequenced, and the corresponding proteins in Drosophila and Anopheles have been identified. The protein has been re-named myofilin. Zeelin 2, which is on the outside of Lethocerus flight muscle thick filaments, has been sequenced and because of the similarity to Drosophila flightin, is re-named flightin. In Drosophila flight muscle, myofilin has a molecular weight of 20 kDa and is one of five isoforms produced from a single gene. In situ hybridisation of Drosophila embryos showed that myofilin RNA is first expressed late in embryogenesis at stage 15, a little later than myosin. Antibody to myofilin labelled the entire A-band, except for the H-zone, in cryosections of flight and non-flight muscle. The periodicity of myofilin in Drosophila flight muscle thick filaments was found to be 30 nm by measuring the spacing of gold particles in labelled cryosections; this is about twice the 14.5 nm spacing of myosin molecules. The molar ratio of myofilin to myosin in indirect flight muscle is 1:2, which is the same as that of flightin. We propose a model for the association of these proteins in thick filaments, which is consistent with the periodicity and stoichiometry. Myofilin is probably needed for filament assembly in all muscles, and flightin for stability of flight muscle thick filaments in adult flies.
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Affiliation(s)
- Feng Qiu
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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Herranz R, Mateos J, Marco R. Diversification and Independent Evolution of Troponin C Genes in Insects. J Mol Evol 2005; 60:31-44. [PMID: 15696366 DOI: 10.1007/s00239-004-0031-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 07/21/2004] [Indexed: 10/25/2022]
Abstract
Troponin C (TpnC), the calcium-binding subunit of the troponin regulatory complex in the muscle thin filament, is encoded by multiple genes in insects. To understand how TpnC genes have evolved, we characterized the gene number and structure in a number of insect species. The TpnC gene complement is five genes in Drosophilidae as previously reported for D. melanogaster. Gene structures are almost identical in D. pseudoobscura, D. suboboscura, and D. virilis. Developmental patterns of expression are also conserved in Drosophila subobscura and D. virilis. Similar, but not completely equivalent, TpnC gene repertoires have been identified in the Anopheles gambiae and Apis mellifera genomes. Insect TpnC sequences can be divided into three groups, allowing a systematic classification of newly identified genes. The pattern of expression of the Apis mellifera genes essentially agrees with the pattern in Drosophilidae, providing further functional support to the classification. A model for the evolution of the TpnC genes is proposed including the most likely pathway of insect TpnC diversification. Our results suggest that the rapid increase in number and sequence specialization of the adult Type III isoforms can be correlated with the evolution of the holometabolous mode of development and the acquisition of asynchronous indirect flight muscle function in insects. This evolutionarily specialization has probably been achieved independently in different insect orders.
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Affiliation(s)
- Raul Herranz
- Departamento de Bioquímica UAM e Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Facultad de Medicina de la Universidad Autónoma, c/ Arzobispo Morcillo 4, 28029 Madrid, Spain
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Linari M, Reedy MK, Reedy MC, Lombardi V, Piazzesi G. Ca-activation and stretch-activation in insect flight muscle. Biophys J 2004; 87:1101-11. [PMID: 15298914 PMCID: PMC1304450 DOI: 10.1529/biophysj.103.037374] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 04/26/2004] [Indexed: 11/18/2022] Open
Abstract
Asynchronous insect flight muscle is specialized for myogenic oscillatory work, but can also produce isometric tetanic contraction. In skinned insect flight muscle fibers from Lethocerus, with sarcomere length monitored by a striation follower, we determined the relation between isometric force (F(0)) at serial increments of [Ca(2+)] and the additional active force recruited at each [Ca(2+)] by a stretch of approximately 12 nm per half-sarcomere (F(SA)). The isometric force-pCa relation shows that 1.5-2 units of pCa are necessary to raise isometric force from its threshold (pCa approximately 6.5) to its maximum (F(0,max)). The amplitude of F(SA) depends only on the preceding baseline level of isometric force, which must reach at least 0.05 F(0,max) to enable stretch-activation. F(SA) rises very steeply to its maximum as F(0) reaches approximately 0.2 F(0,max), then decreases as F(0) increases so as to produce a constant sum (F(0) + F(SA)) = F(max). Thus Ca- and stretch-activation are complementary pathways that trigger a common process of cross-bridge attachment and force production. We suggest that stretch-induced distortion of attached cross-bridges relieves the steric blocking by tropomyosin of additional binding sites on actin, thereby enabling maximum force even at low [Ca(2+)].
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MESH Headings
- Animals
- Calcium/pharmacology
- Cells, Cultured
- Dose-Response Relationship, Drug
- Flight, Animal/physiology
- Heteroptera/drug effects
- Heteroptera/physiology
- Isometric Contraction/drug effects
- Isometric Contraction/physiology
- Magnesium/pharmacology
- Mechanotransduction, Cellular/drug effects
- Mechanotransduction, Cellular/physiology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/physiology
- Physical Stimulation/methods
- Stress, Mechanical
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Affiliation(s)
- Marco Linari
- Laboratorio di Fisiologia, Dipartimento di Biologia Animale e Genetica, Università degli Studi di Firenze and Istituto Nazionale di Fisica della Materia, Firenze, Italy; and Duke University Medical Center, Department of Cellular Biology, Durham, North Carolina
| | - Michael K. Reedy
- Laboratorio di Fisiologia, Dipartimento di Biologia Animale e Genetica, Università degli Studi di Firenze and Istituto Nazionale di Fisica della Materia, Firenze, Italy; and Duke University Medical Center, Department of Cellular Biology, Durham, North Carolina
| | - Mary C. Reedy
- Laboratorio di Fisiologia, Dipartimento di Biologia Animale e Genetica, Università degli Studi di Firenze and Istituto Nazionale di Fisica della Materia, Firenze, Italy; and Duke University Medical Center, Department of Cellular Biology, Durham, North Carolina
| | - Vincenzo Lombardi
- Laboratorio di Fisiologia, Dipartimento di Biologia Animale e Genetica, Università degli Studi di Firenze and Istituto Nazionale di Fisica della Materia, Firenze, Italy; and Duke University Medical Center, Department of Cellular Biology, Durham, North Carolina
| | - Gabriella Piazzesi
- Laboratorio di Fisiologia, Dipartimento di Biologia Animale e Genetica, Università degli Studi di Firenze and Istituto Nazionale di Fisica della Materia, Firenze, Italy; and Duke University Medical Center, Department of Cellular Biology, Durham, North Carolina
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De Nicola G, Biekofsky R, Kelly G, Agianian B, Qiu F, Bullard B, Pastore A. Assignment of the 1H, 13C, and 15N resonances of holo isoform 4 of Lethocerus indicus troponin C. JOURNAL OF BIOMOLECULAR NMR 2004; 29:461-462. [PMID: 15213469 DOI: 10.1023/b:jnmr.0000032558.31512.c8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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Cammarato A, Hatch V, Saide J, Craig R, Sparrow JC, Tobacman LS, Lehman W. Drosophila muscle regulation characterized by electron microscopy and three-dimensional reconstruction of thin filament mutants. Biophys J 2004; 86:1618-24. [PMID: 14990488 PMCID: PMC1303996 DOI: 10.1016/s0006-3495(04)74229-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Accepted: 10/22/2003] [Indexed: 11/26/2022] Open
Abstract
Wild-type and mutant thin filaments were isolated directly from "myosinless" Drosophila indirect flight muscles to study the structural basis of muscle regulation genetically. Negatively stained filaments showed tropomyosin with periodically arranged troponin complexes in electron micrographs. Three-dimensional helical reconstruction of wild-type filaments indicated that the positions of tropomyosin on actin in the presence and absence of Ca(2+) were indistinguishable from those in vertebrate striated muscle and consistent with a steric mechanism of regulation by troponin-tropomyosin in Drosophila muscles. Thus, the Drosophila model can be used to study steric regulation. Thin filaments from the Drosophila mutant heldup(2), which possesses a single amino acid conversion in troponin I, were similarly analyzed to assess the Drosophila model genetically. The positions of tropomyosin in the mutant filaments, in both the Ca(2+)-free and the Ca(2+)-induced states, were the same, and identical to that of wild-type filaments in the presence of Ca(2+). Thus, cross-bridge cycling would be expected to proceed uninhibited in these fibers, even in relaxing conditions, and this would account for the dramatic hypercontraction characteristic of these mutant muscles. The interaction of mutant troponin I with Drosophila troponin C is discussed, along with functional differences between troponin C from Drosophila and vertebrates.
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Affiliation(s)
- Anthony Cammarato
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118-2526, USA
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Agianian B, Kržič U, Qiu F, Linke WA, Leonard K, Bullard B. A troponin switch that regulates muscle contraction by stretch instead of calcium. EMBO J 2004; 23:772-9. [PMID: 14765112 PMCID: PMC381005 DOI: 10.1038/sj.emboj.7600097] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Accepted: 12/05/2003] [Indexed: 01/21/2023] Open
Abstract
The flight muscles of many insects have a form of regulation enabling them to contract at high frequencies. The muscles are activated by periodic stretches at low Ca2+ levels. The same muscles also give isometric contractions in response to higher Ca2+. We show that the two activities are controlled by different isoforms of TnC (F1 and F2) within single myofibrils. F1 binds one Ca2+ with high affinity in the C-terminal domain and F2 binds one Ca2+ in the C-terminal domain and one exchangeable Ca2+ in the N-terminal domain. We have characterised the isoforms and determined their effect on the development of stretch-activated and Ca2+-activated tension by replacing endogenous TnC in Lethocerus flight muscle fibres with recombinant isoforms. Fibres with F1 gave stretch-activated tension and minimal isometric tension; those with F2 gave Ca2+-dependent isometric tension and minimal stretch-activated tension. Regulation by a TnC responding to stretch rather than Ca2+ is unprecedented and has resulted in the ability of insect flight muscle to perform oscillatory work at low Ca2+ concentrations, a property to which a large number of flying insects owe their evolutionary success.
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Affiliation(s)
- Bogos Agianian
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
| | - Uroš Kržič
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Feng Qiu
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
| | - Wolfgang A Linke
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Kevin Leonard
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
| | - Belinda Bullard
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
- European Molecular Biology Laboratory. Meyerhofstrasse 1, D-69117 Heidelberg, Germany. Tel.: +49-6221-387-268; Fax: +49-6221-387-306; E-mail:
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