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Loreau V, Rees R, Chan EH, Taxer W, Gregor K, Mußil B, Pitaval C, Luis NM, Mangeol P, Schnorrer F, Görlich D. A nanobody toolbox to investigate localisation and dynamics of Drosophila titins and other key sarcomeric proteins. eLife 2023; 12:79343. [PMID: 36645120 PMCID: PMC9886281 DOI: 10.7554/elife.79343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 12/16/2022] [Indexed: 01/17/2023] Open
Abstract
Measuring the positions and dynamics of proteins in intact tissues or whole animals is key to understanding protein function. However, to date, this is challenging, as the accessibility of large antibodies to dense tissues is often limited, and fluorescent proteins inserted close to a domain of interest may affect protein function. These complications apply in particular to muscle sarcomeres, arguably one of the most protein-dense assemblies in nature, which complicates studying sarcomere morphogenesis at molecular resolution. Here, we introduce a toolbox of nanobodies recognising various domains of the two Drosophila titin homologs, Sallimus and Projectin, as well as the key sarcomeric proteins Obscurin, α-Actinin, and Zasp52. We verified the superior labelling qualities of our nanobodies in muscle tissue as compared to antibodies. By applying our toolbox to larval muscles, we found a gigantic Sallimus isoform stretching more than 2 µm to bridge the sarcomeric I-band, while Projectin covers almost the entire myosin filaments in a polar orientation. Transgenic expression of tagged nanobodies confirmed their high affinity-binding without affecting target protein function. Finally, adding a degradation signal to anti-Sallimus nanobodies suggested that it is difficult to fully degrade Sallimus in mature sarcomeres; however, expression of these nanobodies caused developmental lethality. These results may inspire the generation of similar toolboxes for other large protein complexes in Drosophila or mammals.
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Affiliation(s)
- Vincent Loreau
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Renate Rees
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Eunice HoYee Chan
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Waltraud Taxer
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Kathrin Gregor
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Bianka Mußil
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Christophe Pitaval
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Nuno Miguel Luis
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Pierre Mangeol
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Frank Schnorrer
- Turing Centre for Living Systems, Aix-Marseille University, CNRS, IDBMMarseilleFrance
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
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Schueder F, Mangeol P, Chan EH, Rees R, Schünemann J, Jungmann R, Görlich D, Schnorrer F. Nanobodies combined with DNA-PAINT super-resolution reveal a staggered titin nanoarchitecture in flight muscles. eLife 2023; 12:79344. [PMID: 36645127 PMCID: PMC9886278 DOI: 10.7554/elife.79344] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 11/22/2022] [Indexed: 01/17/2023] Open
Abstract
Sarcomeres are the force-producing units of all striated muscles. Their nanoarchitecture critically depends on the large titin protein, which in vertebrates spans from the sarcomeric Z-disc to the M-band and hence links actin and myosin filaments stably together. This ensures sarcomeric integrity and determines the length of vertebrate sarcomeres. However, the instructive role of titins for sarcomeric architecture outside of vertebrates is not as well understood. Here, we used a series of nanobodies, the Drosophila titin nanobody toolbox, recognising specific domains of the two Drosophila titin homologs Sallimus and Projectin to determine their precise location in intact flight muscles. By combining nanobodies with DNA-PAINT super-resolution microscopy, we found that, similar to vertebrate titin, Sallimus bridges across the flight muscle I-band, whereas Projectin is located at the beginning of the A-band. Interestingly, the ends of both proteins overlap at the I-band/A-band border, revealing a staggered organisation of the two Drosophila titin homologs. This architecture may help to stably anchor Sallimus at the myosin filament and hence ensure efficient force transduction during flight.
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Affiliation(s)
- Florian Schueder
- Faculty of Physics and Center for Nanoscience, Ludwig Maximilian UniversityMunichGermany
- Max Planck Institute of BiochemistryMartinsriedGermany
| | - Pierre Mangeol
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living SystemsMarseilleFrance
| | - Eunice HoYee Chan
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living SystemsMarseilleFrance
| | - Renate Rees
- Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | | | - Ralf Jungmann
- Faculty of Physics and Center for Nanoscience, Ludwig Maximilian UniversityMunichGermany
- Max Planck Institute of BiochemistryMartinsriedGermany
| | - Dirk Görlich
- Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Frank Schnorrer
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living SystemsMarseilleFrance
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3
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Porto D, Matsunaga Y, Franke B, Williams RM, Qadota H, Mayans O, Benian GM, Lu H. Conformational changes in twitchin kinase in vivo revealed by FRET imaging of freely moving C. elegans. eLife 2021; 10:e66862. [PMID: 34569929 PMCID: PMC8523150 DOI: 10.7554/elife.66862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 09/24/2021] [Indexed: 02/07/2023] Open
Abstract
The force-induced unfolding and refolding of proteins is speculated to be a key mechanism in the sensing and transduction of mechanical signals in the living cell. Yet, little evidence has been gathered for its existence in vivo. Prominently, stretch-induced unfolding is postulated to be the activation mechanism of the twitchin/titin family of autoinhibited sarcomeric kinases linked to the mechanical stress response of muscle. To test the occurrence of mechanical kinase activation in living working muscle, we generated transgenic Caenorhabditis elegans expressing twitchin containing FRET moieties flanking the kinase domain and developed a quantitative technique for extracting FRET signals in freely moving C. elegans, using tracking and simultaneous imaging of animals in three channels (donor fluorescence, acceptor fluorescence, and transmitted light). Computer vision algorithms were used to extract fluorescence signals and muscle contraction states in each frame, in order to obtain fluorescence and body curvature measurements with spatial and temporal precision in vivo. The data revealed statistically significant periodic changes in FRET signals during muscle activity, consistent with a periodic change in the conformation of twitchin kinase. We conclude that stretch-unfolding of twitchin kinase occurs in the active muscle, whereby mechanical activity titrates the signaling pathway of this cytoskeletal kinase. We anticipate that the methods we have developed here could be applied to obtaining in vivo evidence for force-induced conformational changes or elastic behavior of other proteins not only in C. elegans but in other animals in which there is optical transparency (e.g., zebrafish).
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Affiliation(s)
- Daniel Porto
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
| | - Yohei Matsunaga
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Barbara Franke
- Department of Biology, University of KonstanzKonstanzGermany
| | - Rhys M Williams
- Department of Biology, University of KonstanzKonstanzGermany
| | - Hiroshi Qadota
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Olga Mayans
- Department of Biology, University of KonstanzKonstanzGermany
| | - Guy M Benian
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Hang Lu
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
- School of Chemical & Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
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Lesanpezeshki L, Qadota H, Darabad MN, Kashyap K, Lacerda CMR, Szewczyk NJ, Benian GM, Vanapalli SA. Investigating the correlation of muscle function tests and sarcomere organization in C. elegans. Skelet Muscle 2021; 11:20. [PMID: 34389048 PMCID: PMC8362255 DOI: 10.1186/s13395-021-00275-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 07/08/2021] [Indexed: 11/20/2022] Open
Abstract
Background Caenorhabditis elegans has been widely used as a model to study muscle structure and function. Its body wall muscle is functionally and structurally similar to vertebrate skeletal muscle with conserved molecular pathways contributing to sarcomere structure, and muscle function. However, a systematic investigation of the relationship between muscle force and sarcomere organization is lacking. Here, we investigate the contribution of various sarcomere proteins and membrane attachment components to muscle structure and function to introduce C. elegans as a model organism to study the genetic basis of muscle strength. Methods We employ two recently developed assays that involve exertion of muscle forces to investigate the correlation of muscle function to sarcomere organization. We utilized a microfluidic pillar-based platform called NemaFlex that quantifies the maximum exertable force and a burrowing assay that challenges the animals to move in three dimensions under a chemical stimulus. We selected 20 mutants with known defects in various substructures of sarcomeres and compared the physiological function of muscle proteins required for force generation and transmission. We also characterized the degree of sarcomere disorganization using immunostaining approaches. Results We find that mutants with genetic defects in thin filaments, thick filaments, and M-lines are generally weaker, and our assays are successful in detecting the functional changes in response to each sarcomere location tested. We find that the NemaFlex and burrowing assays are functionally distinct informing on different aspects of muscle physiology. Specifically, the burrowing assay has a larger bandwidth in phenotyping muscle mutants, because it could pick ten additional mutants impaired while exerting normal muscle force in NemaFlex. This enabled us to combine their readouts to develop an integrated muscle function score that was found to correlate with the score for muscle structure disorganization. Conclusions Our results highlight the suitability of NemaFlex and burrowing assays for evaluating muscle physiology of C. elegans. Using these approaches, we discuss the importance of the studied sarcomere proteins for muscle function and structure. The scoring methodology we have developed enhances the utility of C. elegans as a genetic model to study muscle function. Supplementary Information The online version contains supplementary material available at 10.1186/s13395-021-00275-4.
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Affiliation(s)
- Leila Lesanpezeshki
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, GA, 30322, USA
| | | | - Karishma Kashyap
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Carla M R Lacerda
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Nathaniel J Szewczyk
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Nottingham, United Kingdom & National Institute for Health Research Nottingham Biomedical Research Centre, Derby, DE22 3DT, UK.,Ohio Musculoskeletal and Neurological Institute (OMNI) and Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA, 30322, USA
| | - Siva A Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
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Subirana JA, Messeguer X. How Long Are Long Tandem Repeats? A Challenge for Current Methods of Whole-Genome Sequence Assembly: The Case of Satellites in Caenorhabditis elegans. Genes (Basel) 2018; 9:genes9100500. [PMID: 30332836 PMCID: PMC6210790 DOI: 10.3390/genes9100500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 11/16/2022] Open
Abstract
Repetitive genome regions have been difficult to sequence, mainly because of the comparatively small size of the fragments used in assembly. Satellites or tandem repeats are very abundant in nematodes and offer an excellent playground to evaluate different assembly methods. Here, we compare the structure of satellites found in three different assemblies of the Caenorhabditis elegans genome: the original sequence obtained by Sanger sequencing, an assembly based on PacBio technology, and an assembly using Nanopore sequencing reads. In general, satellites were found in equivalent genomic regions, but the new long-read methods (PacBio and Nanopore) tended to result in longer assembled satellites. Important differences exist between the assemblies resulting from the two long-read technologies, such as the sizes of long satellites. Our results also suggest that the lengths of some annotated genes with internal repeats which were assembled using Sanger sequencing are likely to be incorrect.
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Affiliation(s)
- Juan A Subirana
- Department of Computer Science, Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034 Barcelona, Spain.
- Evolutionary Genomics Group, Research Program on Biomedical Informatics (GRIB)⁻Hospital del Mar Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Dr. Aiguader 86, 08003 Barcelona, Spain.
| | - Xavier Messeguer
- Department of Computer Science, Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034 Barcelona, Spain.
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6
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Nuclear connectin novex-3 promotes proliferation of hypoxic foetal cardiomyocytes. Sci Rep 2018; 8:12337. [PMID: 30120340 PMCID: PMC6098106 DOI: 10.1038/s41598-018-30886-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/08/2018] [Indexed: 12/15/2022] Open
Abstract
Loss of cardiomyocyte proliferative capacity after birth is a major obstacle for therapeutic heart regeneration in adult mammals. We and others have recently shown the importance of hypoxic in utero environments for active foetal cardiomyocyte proliferation. Here, we report the unexpected expression of novex-3, the short splice variant of the giant sarcomeric protein connectin (titin), in the cardiomyocyte nucleus specifically during the hypoxic foetal stage in mice. This nuclear localisation appeared to be regulated by the N-terminal region of novex-3, which contains the nuclear localisation signal. Importantly, the nuclear expression of novex-3 in hypoxic foetal cardiomyocytes was repressed at the postnatal stage following the onset of breathing and the resulting elevation of oxygen tension, whereas the sarcomeric expression remained unchanged. Novex-3 knockdown in foetal cardiomyocytes repressed cell cycle-promoting genes and proliferation, whereas novex-3 overexpression enhanced proliferation. Mechanical analysis by atomic force microscopy and microneedle-based tensile tests demonstrated that novex-3 expression in hypoxic foetal cardiomyocytes contributes to the elasticity/compliance of the nucleus at interphase and facilitates proliferation, by promoting phosphorylation-induced disassembly of multimer structures of nuclear lamins. We propose that novex-3 has a previously unrecognised role in promoting cardiomyocyte proliferation specifically at the hypoxic foetal stage.
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7
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Fosu-Nyarko J, Tan JACH, Gill R, Agrez VG, Rao U, Jones MGK. De novo analysis of the transcriptome of Pratylenchus zeae to identify transcripts for proteins required for structural integrity, sensation, locomotion and parasitism. MOLECULAR PLANT PATHOLOGY 2016; 17:532-52. [PMID: 26292651 PMCID: PMC6638428 DOI: 10.1111/mpp.12301] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The root lesion nematode Pratylenchus zeae, a migratory endoparasite, is an economically important pest of major crop plants (e.g. cereals, sugarcane). It enters host roots, migrates through root tissues and feeds from cortical cells, and defends itself against biotic and abiotic stresses in the soil and in host tissues. We report de novo sequencing of the P. zeae transcriptome using 454 FLX, and the identification of putative transcripts encoding proteins required for movement, response to stimuli, feeding and parasitism. Sequencing generated 347,443 good quality reads which were assembled into 10,163 contigs and 139,104 singletons: 65% of contigs and 28% of singletons matched sequences of free-living and parasitic nematodes. Three-quarters of the annotated transcripts were common to reference nematodes, mainly representing genes encoding proteins for structural integrity and fundamental biochemical processes. Over 15,000 transcripts were similar to Caenorhabditis elegans genes encoding proteins with roles in mechanical and neural control of movement, responses to chemicals, mechanical and thermal stresses. Notably, 766 transcripts matched parasitism genes employed by both migratory and sedentary endoparasites in host interactions, three of which hybridized to the gland cell region, suggesting that they might be secreted. Conversely, transcripts for effectors reported to be involved in feeding site formation by sedentary endoparasites were conspicuously absent. Transcripts similar to those encoding some secretory-excretory products at the host interface of Brugia malayi, the secretome of Meloidogyne incognita and products of gland cells of Heterodera glycines were also identified. This P. zeae transcriptome provides new information for genome annotation and functional analysis of possible targets for control of pratylenchid nematodes.
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Affiliation(s)
- John Fosu-Nyarko
- Plant Biotechnology Research Group, WA State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia
- Nemgenix Pty Ltd, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, WA, 6150, Australia
| | - Jo-Anne C H Tan
- Plant Biotechnology Research Group, WA State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia
| | - Reetinder Gill
- Plant Biotechnology Research Group, WA State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia
| | - Vaughan G Agrez
- Plant Biotechnology Research Group, WA State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia
| | - Uma Rao
- Division of Nematology, Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Michael G K Jones
- Plant Biotechnology Research Group, WA State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia
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8
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Hwang H, Barnes DE, Matsunaga Y, Benian GM, Ono S, Lu H. Muscle contraction phenotypic analysis enabled by optogenetics reveals functional relationships of sarcomere components in Caenorhabditis elegans. Sci Rep 2016; 6:19900. [PMID: 26822332 PMCID: PMC4731793 DOI: 10.1038/srep19900] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 12/14/2015] [Indexed: 01/22/2023] Open
Abstract
The sarcomere, the fundamental unit of muscle contraction, is a highly-ordered complex of hundreds of proteins. Despite decades of genetics work, the functional relationships and the roles of those sarcomeric proteins in animal behaviors remain unclear. In this paper, we demonstrate that optogenetic activation of the motor neurons that induce muscle contraction can facilitate quantitative studies of muscle kinetics in C. elegans. To increase the throughput of the study, we trapped multiple worms in parallel in a microfluidic device and illuminated for photoactivation of channelrhodopsin-2 to induce contractions in body wall muscles. Using image processing, the change in body size was quantified over time. A total of five parameters including rate constants for contraction and relaxation were extracted from the optogenetic assay as descriptors of sarcomere functions. To potentially relate the genes encoding the sarcomeric proteins functionally, a hierarchical clustering analysis was conducted on the basis of those parameters. Because it assesses physiological output different from conventional assays, this method provides a complement to the phenotypic analysis of C. elegans muscle mutants currently performed in many labs; the clusters may provide new insights and drive new hypotheses for functional relationships among the many sarcomere components.
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Affiliation(s)
- Hyundoo Hwang
- School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Dawn E Barnes
- Department of Pathology, Emory University, Atlanta, GA, USA
| | | | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA, USA
| | - Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, GA, USA
| | - Hang Lu
- School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,Interdisciplinary Program of Bioengineering, Georgia Institute of Technology, Atlanta, GA, USA.,The Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, USA
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9
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Luck AN, Anderson KG, McClung CM, VerBerkmoes NC, Foster JM, Michalski ML, Slatko BE. Tissue-specific transcriptomics and proteomics of a filarial nematode and its Wolbachia endosymbiont. BMC Genomics 2015; 16:920. [PMID: 26559510 PMCID: PMC4642636 DOI: 10.1186/s12864-015-2083-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 10/15/2015] [Indexed: 11/12/2022] Open
Abstract
Background Filarial nematodes cause debilitating human diseases. While treatable, recent evidence suggests drug resistance is developing, necessitating the development of novel targets and new treatment options. Although transcriptomic and proteomic studies around the nematode life cycle have greatly enhanced our knowledge, whole organism approaches have not provided spatial resolution of gene expression, which can be gained by examining individual tissues. Generally, due to their small size, tissue dissection of human-infecting filarial nematodes remains extremely challenging. However, canine heartworm disease is caused by a closely related and much larger filarial nematode, Dirofilaria immitis. As with many other filarial nematodes, D. immitis contains Wolbachia, an obligate bacterial endosymbiont present in the hypodermis and developing oocytes within the uterus. Here, we describe the first concurrent tissue-specific transcriptomic and proteomic profiling of a filarial nematode (D. immitis) and its Wolbachia (wDi) in order to better understand tissue functions and identify tissue-specific antigens that may be used for the development of new diagnostic and therapeutic tools. Methods Adult D. immitis worms were dissected into female body wall (FBW), female uterus (FU), female intestine (FI), female head (FH), male body wall (MBW), male testis (MT), male intestine (MI), male head (MH) and 10.1186/s12864-015-2083-2 male spicule (MS) and used to prepare transcriptomic and proteomic libraries. Results Transcriptomic and proteomic analysis of several D. immitis tissues identified many biological functions enriched within certain tissues. Hierarchical clustering of the D. immitis tissue transcriptomes, along with the recently published whole-worm adult male and female D. immitis transcriptomes, revealed that the whole-worm transcriptome is typically dominated by transcripts originating from reproductive tissue. The uterus appeared to have the most variable transcriptome, possibly due to age. Although many functions are shared between the reproductive tissues, the most significant differences in gene expression were observed between the uterus and testis. Interestingly, wDi gene expression in the male and female body wall is fairly similar, yet slightly different to that of Wolbachia gene expression in the uterus. Proteomic methods verified 32 % of the predicted D. immitis proteome, including over 700 hypothetical proteins of D. immitis. Of note, hypothetical proteins were among some of the most abundant Wolbachia proteins identified, which may fulfill some important yet still uncharacterized biological function. Conclusions The spatial resolution gained from this parallel transcriptomic and proteomic analysis adds to our understanding of filarial biology and serves as a resource with which to develop future therapeutic strategies against filarial nematodes and their Wolbachia endosymbionts. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2083-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ashley N Luck
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Kathryn G Anderson
- Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI, 54901, USA
| | - Colleen M McClung
- Chemical Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Nathan C VerBerkmoes
- Chemical Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Jeremy M Foster
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA
| | - Michelle L Michalski
- Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI, 54901, USA
| | - Barton E Slatko
- Genome Biology Division, New England Biolabs, Inc., 240 County Road, Ipswich, MA, 01938, USA.
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10
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Drebrin-like protein DBN-1 is a sarcomere component that stabilizes actin filaments during muscle contraction. Nat Commun 2015; 6:7523. [PMID: 26146072 DOI: 10.1038/ncomms8523] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/16/2015] [Indexed: 01/22/2023] Open
Abstract
Actin filament organization and stability in the sarcomeres of muscle cells are critical for force generation. Here we identify and functionally characterize a Caenorhabditis elegans drebrin-like protein DBN-1 as a novel constituent of the muscle contraction machinery. In vitro, DBN-1 exhibits actin filament binding and bundling activity. In vivo, DBN-1 is expressed in body wall muscles of C. elegans. During the muscle contraction cycle, DBN-1 alternates location between myosin- and actin-rich regions of the sarcomere. In contracted muscle, DBN-1 is accumulated at I-bands where it likely regulates proper spacing of α-actinin and tropomyosin and protects actin filaments from the interaction with ADF/cofilin. DBN-1 loss of function results in the partial depolymerization of F-actin during muscle contraction. Taken together, our data show that DBN-1 organizes the muscle contractile apparatus maintaining the spatial relationship between actin-binding proteins such as α-actinin, tropomyosin and ADF/cofilin and possibly strengthening actin filaments by bundling.
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11
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Ono S. Regulation of structure and function of sarcomeric actin filaments in striated muscle of the nematode Caenorhabditis elegans. Anat Rec (Hoboken) 2015; 297:1548-59. [PMID: 25125169 DOI: 10.1002/ar.22965] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/26/2014] [Accepted: 02/26/2014] [Indexed: 02/01/2023]
Abstract
The nematode Caenorhabditis elegans has been used as a valuable system to study structure and function of striated muscle. The body wall muscle of C. elegans is obliquely striated muscle with highly organized sarcomeric assembly of actin, myosin, and other accessory proteins. Genetic and molecular biological studies in C. elegans have identified a number of genes encoding structural and regulatory components for the muscle contractile apparatuses, and many of them have counterparts in mammalian cardiac and skeletal muscles or striated muscles in other invertebrates. Applicability of genetics, cell biology, and biochemistry has made C. elegans an excellent system to study mechanisms of muscle contractility and assembly and maintenance of myofibrils. This review focuses on the regulatory mechanisms of structure and function of actin filaments in the C. elegans body wall muscle. Sarcomeric actin filaments in C. elegans muscle are associated with the troponin-tropomyosin system that regulates the actin-myosin interaction. Proteins that bind to the side and ends of actin filaments support ordered assembly of thin filaments. Furthermore, regulators of actin dynamics play important roles in initial assembly, growth, and maintenance of sarcomeres. The knowledge acquired in C. elegans can serve as bases to understand the basic mechanisms of muscle structure and function.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia; Department of Cell Biology, Emory University, Atlanta, Georgia
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12
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Myhre JL, Pilgrim D. A Titan but not necessarily a ruler: assessing the role of titin during thick filament patterning and assembly. Anat Rec (Hoboken) 2015; 297:1604-14. [PMID: 25125174 DOI: 10.1002/ar.22987] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/14/2014] [Indexed: 11/12/2022]
Abstract
The sarcomeres of striated muscle are among the most elaborate and dynamic eukaryotic cellular protein machinery, and the mechanisms by which these semicrystalline filament networks are initially patterned and assembled remain contentious. In addition to the acto-myosin filaments that provide motor function, the sarcomere contains titin filaments, comprised of individual molecules of the giant Ig- and fibronectin domain-rich protein titin. Titin is the largest known protein, containing many structurally distinct domains with a variety of proposed functions, including sarcomere stabilization, the prevention of over-stretching, and returning to resting length after contraction. One molecule of titin, which binds to both the Z-disk and the M-line, spans a half-sarcomere, and is proposed to serve as a "molecular ruler" that dictates the spacing of sarcomeres. The semirigid rod-like A-band region of titin has also been proposed to act as a scaffold for thick filament formation during muscle development, but despite decades of research, this hypothesis has not been rigorously tested. Recent studies in zebrafish have brought into question the necessity for the A-band region of titin during the early stages of sarcomere patterning. In this review, we give an overview of the many different roles of titin in the development and function of striated muscle, and address the validity of the "molecular ruler" model of myofibrillogenesis in light of the current literature.
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Affiliation(s)
- J Layne Myhre
- Faculty of Dentistry, Department of Oral Health Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Benian GM, Mayans O. Titin and obscurin: giants holding hands and discovery of a new Ig domain subset. J Mol Biol 2014; 427:707-714. [PMID: 25555989 DOI: 10.1016/j.jmb.2014.12.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322, USA.
| | - Olga Mayans
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
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Tsai WL, Forbes JG, Wang K. Engineering of an elastic scaffolding polyprotein based on an SH3-binding intrinsically disordered titin PEVK module. Protein Expr Purif 2012; 85:187-99. [PMID: 22910563 PMCID: PMC3463739 DOI: 10.1016/j.pep.2012.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/24/2012] [Accepted: 08/03/2012] [Indexed: 01/21/2023]
Abstract
Titin is a large elastic protein found in muscle that maintains the elasticity and structural integrity of the sarcomere. The PEVK region of titin is intrinsically disordered, highly elastic and serves as a hub to bind signaling proteins. Systematic investigation of the structure and affinity profile of the PEVK region will provide important information about the functions of titin. Since PEVK is highly heterogeneous due to extensive differential splicing from more than one hundred exons, we engineered and expressed polyproteins that consist of a defined number of identical single exon modules. These customized polyproteins reduce heterogeneity, amplify interactions of less dominant modules, and most importantly, provide tags for atomic force microscopy and allow more readily interpretable data from single-molecule techniques. Expression and purification of recombinant polyprotein with repeat regions presented many technical challenges: recombination events in tandem repeats of identical DNA sequences exacerbated by high GC content, toxicity of polymer plasmid and expressed protein to the bacteria; early truncation of proteins expressed with different numbers of modules; and extreme sensitivity to proteolysis. We have investigated a number of in vitro and in vivo bacterial and yeast expression systems, as well as baculoviral systems as potential solutions to these problems. We successfully expressed and purified in gram quantities a polyprotein derived from human titin exon 172 using Pichia pastoris yeast. This study provides valuable insights into the technical challenges regarding the engineering and purification of a tandem repeat sequence of an intrinsically disordered biopolymer.
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Affiliation(s)
- Wanxia Li Tsai
- Muscle Proteomics and Nanotechnology Section, Laboratory of Muscle Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH/DHHS, Bethesda, MD 20892-8024, USA.
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Benian GM, Epstein HF. Caenorhabditis elegans muscle: a genetic and molecular model for protein interactions in the heart. Circ Res 2011; 109:1082-95. [PMID: 21998299 DOI: 10.1161/circresaha.110.237685] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The nematode Caenorhabditis elegans has become established as a major experimental organism with applications to many biomedical research areas. The body wall muscle cells are a useful model for the study of human cardiomyocytes and their homologous structures and proteins. The ability to readily identify mutations affecting these proteins and structures in C elegans and to be able to rigorously characterize their genotypes and phenotypes at the cellular and molecular levels permits mechanistic studies of the responsible interactions relevant to the inherited human cardiomyopathies. Future work in C elegans muscle holds great promise in uncovering new mechanisms in the pathogenesis of these cardiac disorders.
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Affiliation(s)
- Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322, USA.
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Abstract
Proteins provide much of the scaffolding for life, as well as undertaking a variety of essential catalytic reactions. These characteristic functions have led us to presuppose that proteins are in general functional only when well structured and correctly folded. As we begin to explore the repertoire of possible protein sequences inherent in the human and other genomes, two stark facts that belie this supposition become clear: firstly, the number of apparent open reading frames in the human genome is significantly smaller than appears to be necessary to code for all of the diverse proteins in higher organisms, and secondly that a significant proportion of the protein sequences that would be coded by the genome would not be expected to form stable three-dimensional (3D) structures. Clearly the genome must include coding for a multitude of alternative forms of proteins, some of which may be partly or fully disordered or incompletely structured in their functional states. At the same time as this likelihood was recognized, experimental studies also began to uncover examples of important protein molecules and domains that were incompletely structured or completely disordered in solution, yet remained perfectly functional. In the ensuing years, we have seen an explosion of experimental and genome-annotation studies that have mapped the extent of the intrinsic disorder phenomenon and explored the possible biological rationales for its widespread occurrence. Answers to the question 'why would a particular domain need to be unstructured?' are as varied as the systems where such domains are found. This review provides a survey of recent new directions in this field, and includes an evaluation of the role not only of intrinsically disordered proteins but also of partially structured and highly dynamic members of the disorder-order continuum.
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