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Imaging multicellular specimens with real-time optimized tiling light-sheet selective plane illumination microscopy. Nat Commun 2016; 7:11088. [PMID: 27004937 PMCID: PMC4814582 DOI: 10.1038/ncomms11088] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/19/2016] [Indexed: 02/07/2023] Open
Abstract
Despite the progress made in selective plane illumination microscopy, high-resolution 3D live imaging of multicellular specimens remains challenging. Tiling light-sheet selective plane illumination microscopy (TLS-SPIM) with real-time light-sheet optimization was developed to respond to the challenge. It improves the 3D imaging ability of SPIM in resolving complex structures and optimizes SPIM live imaging performance by using a real-time adjustable tiling light sheet and creating a flexible compromise between spatial and temporal resolution. We demonstrate the 3D live imaging ability of TLS-SPIM by imaging cellular and subcellular behaviours in live C. elegans and zebrafish embryos, and show how TLS-SPIM can facilitate cell biology research in multicellular specimens by studying left-right symmetry breaking behaviour of C. elegans embryos. Selective plane illumination microscopy (SPIM) is capable of high-resolution, high-speed 3D imaging of single cells, but application to multicellular samples is challenging. Here the authors develop tiling light sheet SPIM to image large multicellular specimens in 3D with subcellular resolution.
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Davison A, McDowell GS, Holden JM, Johnson HF, Koutsovoulos GD, Liu MM, Hulpiau P, Van Roy F, Wade CM, Banerjee R, Yang F, Chiba S, Davey JW, Jackson DJ, Levin M, Blaxter ML. Formin Is Associated with Left-Right Asymmetry in the Pond Snail and the Frog. Curr Biol 2016; 26:654-60. [PMID: 26923788 PMCID: PMC4791482 DOI: 10.1016/j.cub.2015.12.071] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/01/2015] [Accepted: 12/29/2015] [Indexed: 01/29/2023]
Abstract
While components of the pathway that establishes left-right asymmetry have been identified in diverse animals, from vertebrates to flies, it is striking that the genes involved in the first symmetry-breaking step remain wholly unknown in the most obviously chiral animals, the gastropod snails. Previously, research on snails was used to show that left-right signaling of Nodal, downstream of symmetry breaking, may be an ancestral feature of the Bilateria [1 and 2]. Here, we report that a disabling mutation in one copy of a tandemly duplicated, diaphanous-related formin is perfectly associated with symmetry breaking in the pond snail. This is supported by the observation that an anti-formin drug treatment converts dextral snail embryos to a sinistral phenocopy, and in frogs, drug inhibition or overexpression by microinjection of formin has a chirality-randomizing effect in early (pre-cilia) embryos. Contrary to expectations based on existing models [3, 4 and 5], we discovered asymmetric gene expression in 2- and 4-cell snail embryos, preceding morphological asymmetry. As the formin-actin filament has been shown to be part of an asymmetry-breaking switch in vitro [6 and 7], together these results are consistent with the view that animals with diverse body plans may derive their asymmetries from the same intracellular chiral elements [8].
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Affiliation(s)
- Angus Davison
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Gary S McDowell
- Center for Regenerative and Developmental Biology, and Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Jennifer M Holden
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Harriet F Johnson
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | | | - M Maureen Liu
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Paco Hulpiau
- Department for Biomedical Molecular Biology, Ghent University, and Inflammation Research Center (IRC), VIB, 9052 Ghent, Belgium
| | - Frans Van Roy
- Department for Biomedical Molecular Biology, Ghent University, and Inflammation Research Center (IRC), VIB, 9052 Ghent, Belgium
| | - Christopher M Wade
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Ruby Banerjee
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Fengtang Yang
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Satoshi Chiba
- Community and Ecosystem Ecology, Division of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - John W Davey
- Department for Biomedical Molecular Biology, Ghent University, and Inflammation Research Center (IRC), VIB, 9052 Ghent, Belgium
| | - Daniel J Jackson
- Department of Geobiology, University of Göttingen, Göttingen 37077, Germany
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Mark L Blaxter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK; Edinburgh Genomics, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
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Mao Q, Lecuit T. Mechanochemical Interplay Drives Polarization in Cellular and Developmental Systems. Curr Top Dev Biol 2016; 116:633-57. [DOI: 10.1016/bs.ctdb.2015.11.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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54
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Cytoskeletal Symmetry Breaking and Chirality: From Reconstituted Systems to Animal Development. Symmetry (Basel) 2015. [DOI: 10.3390/sym7042062] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Casar Tena T, Burkhalter MD, Philipp M. Left-right asymmetry in the light of TOR: An update on what we know so far. Biol Cell 2015; 107:306-18. [PMID: 25943139 PMCID: PMC4744706 DOI: 10.1111/boc.201400094] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/29/2015] [Indexed: 01/06/2023]
Abstract
The internal left‐right (LR) asymmetry is a characteristic that exists throughout the animal kingdom from roundworms over flies and fish to mammals. Cilia, which are antenna‐like structures protruding into the extracellular space, are involved in establishing LR asymmetry during early development. Humans who suffer from dysfunctional cilia often develop conditions such as heterotaxy, where internal organs appear to be placed randomly. As a consequence to this failure in asymmetry development, serious complications such as congenital heart defects (CHD) occur. The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has recently emerged as an important regulator regarding symmetry breaking. The mTOR pathway governs fundamental processes such as protein translation or metabolism. Its activity can be transduced by two complexes, which are called TORC1 and TORC2, respectively. So far, only TORC1 has been implicated with asymmetry development and appears to require very precise regulation. A number of recent papers provided evidence that dysregulated TORC1 results in alterations of motile cilia and asymmetry defects. In here, we give an update on what we know so far of mTORC1 in LR asymmetry development.
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Affiliation(s)
- Teresa Casar Tena
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
| | - Martin D Burkhalter
- Leibniz Institute for Age Research Fritz Lippmann Institute, Jena, 07745, Germany
| | - Melanie Philipp
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, 89081, Germany
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Inferring regulatory networks from experimental morphological phenotypes: a computational method reverse-engineers planarian regeneration. PLoS Comput Biol 2015; 11:e1004295. [PMID: 26042810 PMCID: PMC4456145 DOI: 10.1371/journal.pcbi.1004295] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 04/21/2015] [Indexed: 01/18/2023] Open
Abstract
Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method provides an automated, highly generalizable framework for identifying the underlying control mechanisms responsible for the dynamic regulation of growth and form. Developmental and regenerative biology experiments are producing a huge number of morphological phenotypes from functional perturbation experiments. However, existing pathway models do not generally explain the dynamic regulation of anatomical shape due to the difficulty of inferring and testing non-linear regulatory networks responsible for appropriate form, shape, and pattern. We present a method that automates the discovery and testing of regulatory networks explaining morphological outcomes directly from the resultant phenotypes, producing network models as testable hypotheses explaining regeneration data. Our system integrates a formalization of the published results in planarian regeneration, an in silico simulator in which the patterning properties of regulatory networks can be quantitatively tested in a regeneration assay, and a machine learning module that evolves networks whose behavior in this assay optimally matches the database of planarian results. We applied our method to explain the key experiments in planarian regeneration, and discovered the first comprehensive model of anterior-posterior patterning in planaria under surgical, pharmacological, and genetic manipulations. Beyond the planarian data, our approach is readily generalizable to facilitate the discovery of testable regulatory networks in developmental biology and biomedicine, and represents the first developmental model discovered de novo from morphological outcomes by an automated system.
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Schonegg S, Hyman AA, Wood WB. Timing and mechanism of the initial cue establishing handed left–right asymmetry in Caenorhabditis elegans embryos. Genesis 2015; 52:572-80. [PMID: 25077289 DOI: 10.1002/dvg.22749] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
By the six-cell stage, embryos of Caenorhabditis elegans are morphologically L–R asymmetric with an invariant handedness that persists throughout development. We used intracellular markers to ask whether breaking of L–R symmetry could be observed at earlier stages. Observation of two- to three-cell embryos carrying intracellular markers indicated that L–R symmetry is broken concomitantly with establishment of D–V axis polarity during division of the anterior AB cell. The AB cleavage furrow initiates asymmetrically and always from the left, suggesting L–R differences in the AB cell cortex. An invariantly handed cortical rotation observed earlier during first cleavage implies that the one-cell embryo has an intrinsic chirality. We propose that L–R differences in the cortex could result from mechanical forces on asymmetric components of a chiral cortical network during the off-axis elongation of the AB-cell spindle prior to AB cleavage.
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Naganathan SR, Fürthauer S, Nishikawa M, Jülicher F, Grill SW. Active torque generation by the actomyosin cell cortex drives left-right symmetry breaking. eLife 2014; 3:e04165. [PMID: 25517077 PMCID: PMC4269833 DOI: 10.7554/elife.04165] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 11/12/2014] [Indexed: 12/11/2022] Open
Abstract
Many developmental processes break left-right (LR) symmetry with a consistent handedness. LR asymmetry emerges early in development, and in many species the primary determinant of this asymmetry has been linked to the cytoskeleton. However, the nature of the underlying chirally asymmetric cytoskeletal processes has remained elusive. In this study, we combine thin-film active chiral fluid theory with experimental analysis of the C. elegans embryo to show that the actomyosin cortex generates active chiral torques to facilitate chiral symmetry breaking. Active torques drive chiral counter-rotating cortical flow in the zygote, depend on myosin activity, and can be altered through mild changes in Rho signaling. Notably, they also execute the chiral skew event at the 4-cell stage to establish the C. elegans LR body axis. Taken together, our results uncover a novel, large-scale physical activity of the actomyosin cytoskeleton that provides a fundamental mechanism for chiral morphogenesis in development.
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Affiliation(s)
- Sundar Ram Naganathan
- Biotechnology Center, Technical University Dresden, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Sebastian Fürthauer
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Masatoshi Nishikawa
- Biotechnology Center, Technical University Dresden, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Stephan W Grill
- Biotechnology Center, Technical University Dresden, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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60
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Krüger AV, Jelier R, Dzyubachyk O, Zimmerman T, Meijering E, Lehner B. Comprehensive single cell-resolution analysis of the role of chromatin regulators in early C. elegans embryogenesis. Dev Biol 2014; 398:153-62. [PMID: 25446273 DOI: 10.1016/j.ydbio.2014.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 09/12/2014] [Accepted: 10/17/2014] [Indexed: 11/19/2022]
Abstract
Chromatin regulators are widely expressed proteins with diverse roles in gene expression, nuclear organization, cell cycle regulation, pluripotency, physiology and development, and are frequently mutated in human diseases such as cancer. Their inhibition often results in pleiotropic effects that are difficult to study using conventional approaches. We have developed a semi-automated nuclear tracking algorithm to quantify the divisions, movements and positions of all nuclei during the early development of Caenorhabditis elegans and have used it to systematically study the effects of inhibiting chromatin regulators. The resulting high dimensional datasets revealed that inhibition of multiple regulators, including F55A3.3 (encoding FACT subunit SUPT16H), lin-53 (RBBP4/7), rba-1 (RBBP4/7), set-16 (MLL2/3), hda-1 (HDAC1/2), swsn-7 (ARID2), and let-526 (ARID1A/1B) affected cell cycle progression and caused chromosome segregation defects. In contrast, inhibition of cir-1 (CIR1) accelerated cell division timing in specific cells of the AB lineage. The inhibition of RNA polymerase II also accelerated these division timings, suggesting that normal gene expression is required to delay cell cycle progression in multiple lineages in the early embryo. Quantitative analyses of the dataset suggested the existence of at least two functionally distinct SWI/SNF chromatin remodeling complex activities in the early embryo, and identified a redundant requirement for the egl-27 and lin-40 MTA orthologs in the development of endoderm and mesoderm lineages. Moreover, our dataset also revealed a characteristic rearrangement of chromatin to the nuclear periphery upon the inhibition of multiple general regulators of gene expression. Our systematic, comprehensive and quantitative datasets illustrate the power of single cell-resolution quantitative tracking and high dimensional phenotyping to investigate gene function. Furthermore, the results provide an overview of the functions of essential chromatin regulators during the early development of an animal.
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Affiliation(s)
- Angela V Krüger
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain; University Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Rob Jelier
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain; University Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Oleh Dzyubachyk
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Timo Zimmerman
- Advanced Light Microscopy Facility, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Erik Meijering
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus MC - University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Ben Lehner
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain; University Pompeu Fabra (UPF), 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain.
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61
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Dejima K, Kang S, Mitani S, Cosman PC, Chisholm AD. Syndecan defines precise spindle orientation by modulating Wnt signaling in C. elegans. Development 2014; 141:4354-65. [PMID: 25344071 DOI: 10.1242/dev.113266] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Wnt signals orient mitotic spindles in development, but it remains unclear how Wnt signaling is spatially controlled to achieve precise spindle orientation. Here, we show that C. elegans syndecan (SDN-1) is required for precise orientation of a mitotic spindle in response to a Wnt cue. We find that SDN-1 is the predominant heparan sulfate (HS) proteoglycan in the early C. elegans embryo, and that loss of HS biosynthesis or of the SDN-1 core protein results in misorientation of the spindle of the ABar blastomere. The ABar and EMS spindles both reorient in response to Wnt signals, but only ABar spindle reorientation is dependent on a new cell contact and on HS and SDN-1. SDN-1 transiently accumulates on the ABar surface as it contacts C, and is required for local concentration of Dishevelled (MIG-5) in the ABar cortex adjacent to C. These findings establish a new role for syndecan in Wnt-dependent spindle orientation.
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Affiliation(s)
- Katsufumi Dejima
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Sukryool Kang
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Pamela C Cosman
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Andrew D Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Coutelis JB, González-Morales N, Géminard C, Noselli S. Diversity and convergence in the mechanisms establishing L/R asymmetry in metazoa. EMBO Rep 2014; 15:926-37. [PMID: 25150102 DOI: 10.15252/embr.201438972] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Differentiating left and right hand sides during embryogenesis represents a major event in body patterning. Left-Right (L/R) asymmetry in bilateria is essential for handed positioning, morphogenesis and ultimately the function of organs (including the brain), with defective L/R asymmetry leading to severe pathologies in human. How and when symmetry is initially broken during embryogenesis remains debated and is a major focus in the field. Work done over the past 20 years, in both vertebrate and invertebrate models, has revealed a number of distinct pathways and mechanisms important for establishing L/R asymmetry and for spreading it to tissues and organs. In this review, we summarize our current knowledge and discuss the diversity of L/R patterning from cells to organs during evolution.
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Affiliation(s)
- Jean-Baptiste Coutelis
- Institut de Biologie Valrose University of Nice Sophia Antipolis, Nice, France CNRS Institut de Biologie Valrose UMR 7277, Nice, France INSERM Institut de Biologie Valrose U1091, Nice, France
| | - Nicanor González-Morales
- Institut de Biologie Valrose University of Nice Sophia Antipolis, Nice, France CNRS Institut de Biologie Valrose UMR 7277, Nice, France INSERM Institut de Biologie Valrose U1091, Nice, France
| | - Charles Géminard
- Institut de Biologie Valrose University of Nice Sophia Antipolis, Nice, France CNRS Institut de Biologie Valrose UMR 7277, Nice, France INSERM Institut de Biologie Valrose U1091, Nice, France
| | - Stéphane Noselli
- Institut de Biologie Valrose University of Nice Sophia Antipolis, Nice, France CNRS Institut de Biologie Valrose UMR 7277, Nice, France INSERM Institut de Biologie Valrose U1091, Nice, France
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63
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Noël ES, Verhoeven M, Lagendijk AK, Tessadori F, Smith K, Choorapoikayil S, den Hertog J, Bakkers J. A Nodal-independent and tissue-intrinsic mechanism controls heart-looping chirality. Nat Commun 2014; 4:2754. [PMID: 24212328 DOI: 10.1038/ncomms3754] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 10/10/2013] [Indexed: 12/21/2022] Open
Abstract
Breaking left-right symmetry in bilateria is a major event during embryo development that is required for asymmetric organ position, directional organ looping and lateralized organ function in the adult. Asymmetric expression of Nodal-related genes is hypothesized to be the driving force behind regulation of organ laterality. Here we identify a Nodal-independent mechanism that drives asymmetric heart looping in zebrafish embryos. In a unique mutant defective for the Nodal-related southpaw gene, preferential dextral looping in the heart is maintained, whereas gut and brain asymmetries are randomized. As genetic and pharmacological inhibition of Nodal signalling does not abolish heart asymmetry, a yet undiscovered mechanism controls heart chirality. This mechanism is tissue intrinsic, as explanted hearts maintain ex vivo retain chiral looping behaviour and require actin polymerization and myosin II activity. We find that Nodal signalling regulates actin gene expression, supporting a model in which Nodal signalling amplifies this tissue-intrinsic mechanism of heart looping.
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Affiliation(s)
- Emily S Noël
- Hubrecht Institute-KNAW and University Medical Center Utrecht, 3584CT Utrecht, The Netherlands
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Hatori R, Ando T, Sasamura T, Nakazawa N, Nakamura M, Taniguchi K, Hozumi S, Kikuta J, Ishii M, Matsuno K. Left-right asymmetry is formed in individual cells by intrinsic cell chirality. Mech Dev 2014; 133:146-62. [PMID: 24800645 DOI: 10.1016/j.mod.2014.04.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/26/2014] [Accepted: 04/14/2014] [Indexed: 01/20/2023]
Abstract
Many animals show left-right (LR) asymmetric morphology. The mechanisms of LR asymmetric development are evolutionarily divergent, and they remain elusive in invertebrates. Various organs in Drosophila melanogaster show stereotypic LR asymmetry, including the embryonic gut. The Drosophila embryonic hindgut twists 90° left-handedly, thereby generating directional LR asymmetry. We recently revealed that the hindgut epithelial cell is chiral in shape and other properties; this is termed planar cell chirality (PCC). We previously showed by computer modeling that PCC is sufficient to induce the hindgut rotation. In addition, both the PCC and the direction of hindgut twisting are reversed in Myosin31DF (Myo31DF) mutants. Myo31DF encodes Drosophila MyosinID, an actin-based motor protein, whose molecular functions in LR asymmetric development are largely unknown. Here, to understand how PCC directs the asymmetric cell-shape, we analyzed PCC in genetic mosaics composed of cells homozygous for mutant Myo31DF, some of which also overexpressed wild-type Myo31DF. Wild-type cell-shape chirality only formed in the Myo31DF-overexpressing cells, suggesting that cell-shape chirality was established in each cell and reflects intrinsic PCC. A computer model recapitulating the development of this genetic mosaic suggested that mechanical interactions between cells are required for the cell-shape behavior seen in vivo. Our mosaic analysis also suggested that during hindgut rotation in vivo, wild-type Myo31DF suppresses the elongation of cell boundaries, supporting the idea that cell-shape chirality is an intrinsic property determined in each cell. However, the amount and distribution of F-actin and Myosin II, which are known to help generate the contraction force on cell boundaries, did not show differences between Myo31DF mutant cells and wild-type cells, suggesting that the static amount and distribution of these proteins are not involved in the suppression of cell-boundary elongation. Taken together, our results suggest that cell-shape chirality is intrinsically formed in each cell, and that mechanical force from intercellular interactions contributes to its formation and/or maintenance.
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Affiliation(s)
- Ryo Hatori
- Department of Biological Science and Technology, Tokyo University of Science, Katsushika, Tokyo 122-8585, Japan; Department of Biological Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Tadashi Ando
- Laboratory for Biomolecular Function Simulation, Computational Biology Research Core, RIKEN Quantitative Biology Center (QBiC), Kobe, Hyogo 650-0047, Japan
| | - Takeshi Sasamura
- Department of Biological Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Naotaka Nakazawa
- Department of Biological Science and Technology, Tokyo University of Science, Katsushika, Tokyo 122-8585, Japan; Department of Biological Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Mitsutoshi Nakamura
- Department of Biological Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Kiichiro Taniguchi
- Department of Biological Science and Technology, Tokyo University of Science, Katsushika, Tokyo 122-8585, Japan
| | - Shunya Hozumi
- Department of Biological Science and Technology, Tokyo University of Science, Katsushika, Tokyo 122-8585, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kenji Matsuno
- Department of Biological Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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65
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Singh D, Pohl C. Coupling of rotational cortical flow, asymmetric midbody positioning, and spindle rotation mediates dorsoventral axis formation in C. elegans. Dev Cell 2014; 28:253-67. [PMID: 24525186 DOI: 10.1016/j.devcel.2014.01.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 12/02/2013] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
Abstract
Cortical flows mediate anteroposterior polarization in Caenorhabditis elegans by generating two mutually exclusive membrane domains. However, factors downstream of anteroposterior polarity that establish the dorsoventral axis remain elusive. Here, we show that rotational cortical flow orthogonal to the anteroposterior axis during the division of the AB blastomere in the two-cell embryo positions the cytokinetic midbody remnant of the previous division asymmetrically at the future ventral side of the embryo. In the neighboring P1 blastomere, astral microtubules contact a transient PAR-2-dependent actin coat that forms asymmetrically onto the midbody remnant-P1 interface. Ablation of the midbody remnant or perturbation of rotational cortical flow reveals that microtubule-midbody remnant contacts are crucial for P1 spindle rotation and dorsoventral axis formation. Thus, our findings suggest a mechanism for dorsoventral patterning that relies on coupling of anteroposterior polarity, rotational cortical flow, midbody remnant positioning, and spindle orientation.
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Affiliation(s)
- Deepika Singh
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt (Main), Germany
| | - Christian Pohl
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt (Main), Germany.
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66
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Namigai EK, Kenny NJ, Shimeld SM. Right across the tree of life: The evolution of left-right asymmetry in the Bilateria. Genesis 2014; 52:458-70. [DOI: 10.1002/dvg.22748] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Erica K.O. Namigai
- Department of Zoology; University of Oxford; South Parks Road Oxford United Kingdom
| | - Nathan J. Kenny
- Department of Zoology; University of Oxford; South Parks Road Oxford United Kingdom
| | - Sebastian M. Shimeld
- Department of Zoology; University of Oxford; South Parks Road Oxford United Kingdom
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67
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Abstract
The satellite symposium on 'Making and breaking the left-right axis: implications of laterality in development and disease' was held in June 2013 in conjunction with the 17th International Society for Developmental Biology meeting in Cancún, Mexico. As we summarize here, leaders in the field gathered at the symposium to discuss recent advances in understanding how left-right asymmetry is generated and utilized across the animal kingdom.
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Affiliation(s)
- Rebecca D Burdine
- Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA
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68
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Vandenberg LN, Lemire JM, Levin M. It's never too early to get it Right: A conserved role for the cytoskeleton in left-right asymmetry. Commun Integr Biol 2013; 6:e27155. [PMID: 24505508 PMCID: PMC3912007 DOI: 10.4161/cib.27155] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 01/08/2023] Open
Abstract
For centuries, scientists and physicians have been captivated by the consistent left-right (LR) asymmetry of the heart, viscera, and brain. A recent study implicated tubulin proteins in establishing laterality in several experimental models, including asymmetric chemosensory receptor expression in C. elegans neurons, polarization of HL-60 human neutrophil-like cells in culture, and asymmetric organ placement in Xenopus. The same mutations that randomized asymmetry in these diverse systems also affect chirality in Arabidopsis, revealing a remarkable conservation of symmetry-breaking mechanisms among kingdoms. In Xenopus, tubulin mutants only affected LR patterning very early, suggesting that this axis is established shortly after fertilization. This addendum summarizes and extends the knowledge of the cytoskeleton's role in the patterning of the LR axis. Results from many species suggest a conserved role for the cytoskeleton as the initiator of asymmetry, and indicate that symmetry is first broken during early embryogenesis by an intracellular process.
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Affiliation(s)
- Laura N Vandenberg
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA ; Current affiliation: Department of Public Health; Division of Environmental Health Sciences; University of Massachusetts, Amherst; Amherst, MA USA
| | - Joan M Lemire
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA
| | - Michael Levin
- Biology Department; Center for Regenerative and Developmental Biology; Tufts University; Medford, MA USA
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69
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Ma K. Embryonic left-right separation mechanism allows confinement of mutation-induced phenotypes to one lateral body half of bilaterians. Am J Med Genet A 2013; 161A:3095-114. [PMID: 24254848 DOI: 10.1002/ajmg.a.36188] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 07/16/2013] [Indexed: 11/08/2022]
Abstract
A fundamental question in developmental biology is how a chimeric animal such as a bilateral gynandromorphic animal can have different phenotypes confined to different lateral body halves, and how mutation-induced phenotypes, such as genetic diseases, can be confined to one lateral body half in patients. Here, I propose that embryos of many, if not all, bilaterian animals are divided into left and right halves at a very early stage (which may vary among different types of animals), after which the descendants of the left-sided and right-sided cells will almost exclusively remain on their original sides, respectively, throughout the remaining development. This embryonic left-right separation mechanism allows (1) mutations and the mutation-induced phenotypes to be strictly confined to one lateral body half in animals and humans; (2) mothers with bilateral hereditary primary breast cancer to transmit their disease to their offspring at twofold of the rate compared to mothers with unilateral hereditary breast cancer; and (3) a mosaic embryo carrying genetic or epigenetic mutations to develop into either an individual with the mutation-induced phenotype confined unilaterally, or a pair of twins displaying complete, partial, or mirror-image discordance for the phenotype. Further, this left-right separation mechanism predicts that the two lateral halves of a patient carrying a unilateral genetic disease can each serve as a case and an internal control, respectively, for genetic and epigenetic comparative studies to identify the disease causations.
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70
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Moore JL, Du Z, Bao Z. Systematic quantification of developmental phenotypes at single-cell resolution during embryogenesis. Development 2013; 140:3266-74. [PMID: 23861063 DOI: 10.1242/dev.096040] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Current imaging technology provides an experimental platform in which complex developmental processes can be observed at cellular resolution over an extended time frame. New computational tools are essential to achieve a systems-level understanding of this high-content information. We have devised a structured approach to systematically analyze complex in vivo phenotypes at cellular resolution, which divides the task into a panel of statistical measurements of each cell in terms of cell differentiation, proliferation and morphogenesis, followed by their spatial and temporal organization in groups and the cohesion within the whole specimen. We demonstrate the approach to C. elegans embryogenesis with in toto imaging and automated cell lineage tracing. We define statistical distributions of the wild-type developmental behaviors at single-cell resolution based on over 50 embryos, cumulating in over 4000 distinct, developmentally based measurements per embryo. These methods enable statistical quantification of abnormalities in mutant or RNAi-treated embryos and a rigorous comparison of embryos by testing each measurement for the probability that it would occur in a wild-type embryo. We demonstrate the power of this structured approach by uncovering quantitative properties including subtle phenotypes in both wild-type and perturbed embryos, transient behaviors that lead to new insights into gene function and a previously undetected source of developmental noise and its subsequent correction.
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Affiliation(s)
- Julia L Moore
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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71
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Wan LQ, Ronaldson K, Guirguis M, Vunjak-Novakovic G. Micropatterning of cells reveals chiral morphogenesis. Stem Cell Res Ther 2013; 4:24. [PMID: 23672821 PMCID: PMC3706915 DOI: 10.1186/scrt172] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Invariant left-right (LR) patterning or chirality is critical for embryonic development. The loss or reversal of LR asymmetry is often associated with malformations and disease. Although several theories have been proposed, the exact mechanism of the initiation of the LR symmetry has not yet been fully elucidated. Recently, chirality has been detected within single cells as well as multicellular structures using several in vitro approaches. These studies demonstrated the universality of cell chirality, its dependence on cell phenotype, and the role of physical boundaries. In this review, we discuss the theories for developmental LR asymmetry, compare various in vitro cell chirality model systems, and highlight possible roles of cell chirality in stem cell differentiation. We emphasize that the in vitro cell chirality systems have great promise for helping unveil the nature of chiral morphogenesis in development.
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72
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Noninvasive imaging beyond the diffraction limit of 3D dynamics in thickly fluorescent specimens. Cell 2013; 151:1370-85. [PMID: 23217717 PMCID: PMC3615549 DOI: 10.1016/j.cell.2012.10.008] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 06/20/2012] [Accepted: 10/01/2012] [Indexed: 11/22/2022]
Abstract
Optical imaging of the dynamics of living specimens involves tradeoffs between spatial resolution, temporal resolution, and phototoxicity, made more difficult in three dimensions. Here, however, we report that rapid three-dimensional (3D) dynamics can be studied beyond the diffraction limit in thick or densely fluorescent living specimens over many time points by combining ultrathin planar illumination produced by scanned Bessel beams with super-resolution structured illumination microscopy. We demonstrate in vivo karyotyping of chromosomes during mitosis and identify different dynamics for the actin cytoskeleton at the dorsal and ventral surfaces of fibroblasts. Compared to spinning disk confocal microscopy, we demonstrate substantially reduced photodamage when imaging rapid morphological changes in D. discoideum cells, as well as improved contrast and resolution at depth within developing C. elegans embryos. Bessel beam structured plane illumination thus promises new insights into complex biological phenomena that require 4D subcellular spatiotemporal detail in either a single or multicellular context.
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73
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Fürthauer S, Strempel M, Grill SW, Jülicher F. Active chiral processes in thin films. PHYSICAL REVIEW LETTERS 2013; 110:048103. [PMID: 25166204 DOI: 10.1103/physrevlett.110.048103] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 10/12/2012] [Indexed: 06/03/2023]
Abstract
We develop a generic description of thin active films that captures key features of flow and rotation patterns emerging from the activity of chiral motors which introduce torque dipoles. We highlight the role of the spin rotation field and show that fluid flows can occur in two ways: by coupling of the spin rotation rate to the velocity field via a surface or by spatial gradients of the spin rotation rate. We discuss our results in the context of patches of bacteria on solid surfaces and groups of rotating cilia. Our theory could apply to active chiral processes in the cell cytoskeleton and in epithelia.
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Affiliation(s)
- S Fürthauer
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - M Strempel
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - S W Grill
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - F Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
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74
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Coordinated lumen contraction and expansion during vulval tube morphogenesis in Caenorhabditis elegans. Dev Cell 2013; 23:494-506. [PMID: 22975323 DOI: 10.1016/j.devcel.2012.06.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 04/06/2012] [Accepted: 06/29/2012] [Indexed: 11/20/2022]
Abstract
Morphogenesis is a developmental phase during which cell fates are executed. Mechanical forces shaping individual cells play a key role during tissue morphogenesis. By investigating morphogenesis of the Caenorhabditis elegans hermaphrodite vulva, we show that the force-generating actomyosin network is differentially regulated by NOTCH and EGFR/RAS/MAPK signaling to shape the vulval tube. NOTCH signaling activates expression of the RHO kinase LET-502 in the secondary cell lineage through the ETS-family transcription factor LIN-1. LET-502 induces actomyosin-mediated contraction of the apical lumen in the secondary toroids, thereby generating a dorsal pushing force. In contrast, MAPK signaling in the primary lineage downregulates LET-502 RHO kinase expression to prevent toroid contraction and allow the gonadal anchor cell to expand the dorsal lumen of the primary toroids. The antagonistic action of the MAPK and NOTCH pathways thus controls vulval tube morphogenesis linking cell fate specification to morphogenesis.
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75
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Pohl C, Tiongson M, Moore JL, Santella A, Bao Z. Actomyosin-based self-organization of cell internalization during C. elegans gastrulation. BMC Biol 2012; 10:94. [PMID: 23198792 PMCID: PMC3583717 DOI: 10.1186/1741-7007-10-94] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 11/30/2012] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Gastrulation is a key transition in embryogenesis; it requires self-organized cellular coordination, which has to be both robust to allow efficient development and plastic to provide adaptability. Despite the conservation of gastrulation as a key event in Metazoan embryogenesis, the morphogenetic mechanisms of self-organization (how global order or coordination can arise from local interactions) are poorly understood. RESULTS We report a modular structure of cell internalization in Caenorhabditis elegans gastrulation that reveals mechanisms of self-organization. Cells that internalize during gastrulation show apical contractile flows, which are correlated with centripetal extensions from surrounding cells. These extensions converge to seal over the internalizing cells in the form of rosettes. This process represents a distinct mode of monolayer remodeling, with gradual extrusion of the internalizing cells and simultaneous tissue closure without an actin purse-string. We further report that this self-organizing module can adapt to severe topological alterations, providing evidence of scalability and plasticity of actomyosin-based patterning. Finally, we show that globally, the surface cell layer undergoes coplanar division to thin out and spread over the internalizing mass, which resembles epiboly. CONCLUSIONS The combination of coplanar division-based spreading and recurrent local modules for piecemeal internalization constitutes a system-level solution of gradual volume rearrangement under spatial constraint. Our results suggest that the mode of C. elegans gastrulation can be unified with the general notions of monolayer remodeling and with distinct cellular mechanisms of actomyosin-based morphogenesis.
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Affiliation(s)
- Christian Pohl
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt, Germany
| | - Michael Tiongson
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
| | - Julia L Moore
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
- Program in Computational Biology and Medicine, Cornell University, 1300 York Avenue, New York, NY, 10065, USA
| | - Anthony Santella
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
| | - Zhirong Bao
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
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76
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Wong MN, Nguyen TP, Chen TH, Hsu JJ, Zeng X, Saw A, Demer EM, Zhao X, Tintut Y, Demer LL. Preferred mitotic orientation in pattern formation by vascular mesenchymal cells. Am J Physiol Heart Circ Physiol 2012; 303:H1411-7. [PMID: 23064835 DOI: 10.1152/ajpheart.00625.2012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Cellular self-organization is essential to physiological tissue and organ development. We previously observed that vascular mesenchymal cells, a multipotent subpopulation of aortic smooth muscle cells, self-organize into macroscopic, periodic patterns in culture. The patterns are produced by cells gathering into raised aggregates in the shape of nodules or ridges. To determine whether these patterns are accounted for by an oriented pattern of cell divisions or postmitotic relocation of cells, we acquired time-lapse, videomicrographic phase-contrast, and fluorescence images during self-organization. Cell division events were analyzed for orientation of daughter cells in mitoses during separation and their angle relative to local cell alignment, and frequency distribution of the mitotic angles was analyzed by both histographic and bin-free statistical methods. Results showed a statistically significant preferential orientation of daughter cells along the axis of local cell alignment as early as day 8, just before aggregate formation. This alignment of mitotic axes was also statistically significant at the time of aggregate development (day 11) and after aggregate formation was complete (day 15). Treatment with the nonmuscle myosin II inhibitor, blebbistatin, attenuated alignment of mitotic orientation, whereas Rho kinase inhibition eliminated local cell alignment, suggesting a role for stress fiber orientation in this self-organization. Inhibition of cell division using mitomycin C reduced the macroscopic pattern formation. Time-lapse monitoring of individual cells expressing green fluorescent protein showed postmitotic movement of cells into neighboring aggregates. These findings suggest that polarization of mitoses and postmitotic migration of cells both contribute to self-organization into periodic, macroscopic patterns in vascular stem cells.
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Affiliation(s)
- Margaret N Wong
- Department of Bioengineering, University of California, Los Angeles, USA
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77
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Abstract
A recently developed technique enables quantitative study of the initiation of left-right asymmetry using cells grown on micropatterns with close appositional boundaries. It was found that mammalian cells exhibit either a left or right bias in their migratory behavior, which was determined by cell phenotype, different for certain cancer and normal cells, and dependent on functionality of the actin cytoskeleton. We discuss here the relevance of this simple technique to study of development and birth defects in laterality.
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Affiliation(s)
- Leo Q Wan
- Department of Biomedical Engineering; Columbia University; New York, NY USA
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78
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Fürthauer S, Strempel M, Grill SW, Jülicher F. Active chiral fluids. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:89. [PMID: 23001784 DOI: 10.1140/epje/i2012-12089-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 07/25/2012] [Accepted: 08/17/2012] [Indexed: 06/01/2023]
Abstract
Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.
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Affiliation(s)
- S Fürthauer
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
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79
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Chen TH, Hsu JJ, Zhao X, Guo C, Wong MN, Huang Y, Li Z, Garfinkel A, Ho CM, Tintut Y, Demer LL. Left-right symmetry breaking in tissue morphogenesis via cytoskeletal mechanics. Circ Res 2012; 110:551-9. [PMID: 22223355 PMCID: PMC3288887 DOI: 10.1161/circresaha.111.255927] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RATIONALE Left-right (LR) asymmetry is ubiquitous in animal development. Cytoskeletal chirality was recently reported to specify LR asymmetry in embryogenesis, suggesting that LR asymmetry in tissue morphogenesis is coordinated by single- or multi-cell organizers. Thus, to organize LR asymmetry at multiscale levels of morphogenesis, cells with chirality must also be present in adequate numbers. However, observation of LR asymmetry is rarely reported in cultured cells. OBJECTIVES Using cultured vascular mesenchymal cells, we tested whether LR asymmetry occurs at the single cell level and in self-organized multicellular structures. METHODS AND RESULTS Using micropatterning, immunofluorescence revealed that adult vascular cells polarized rightward and accumulated stress fibers at an unbiased mechanical interface between adhesive and nonadhesive substrates. Green fluorescent protein transfection revealed that the cells each turned rightward at the interface, aligning into a coherent orientation at 20° relative to the interface axis at confluence. During the subsequent aggregation stage, time-lapse videomicroscopy showed that cells migrated along the same 20° angle into neighboring aggregates, resulting in a macroscale structure with LR asymmetry as parallel, diagonal stripes evenly spaced throughout the culture. Removal of substrate interface by shadow mask-plating, or inhibition of Rho kinase or nonmuscle myosin attenuated stress fiber accumulation and abrogated LR asymmetry of both single-cell polarity and multicellular coherence, suggesting that the interface triggers asymmetry via cytoskeletal mechanics. Examination of other cell types suggests that LR asymmetry is cell-type specific. CONCLUSIONS Our results show that adult stem cells retain inherent LR asymmetry that elicits de novo macroscale tissue morphogenesis, indicating that mechanical induction is required for cellular LR specification.
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Affiliation(s)
- Ting-Hsuan Chen
- Department of Medicine, University of California Los Angeles, 10833 LeConte Avenue, Los Angeles, CA 90095-1679, USA
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80
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Abstract
Tissue and organ architectures are incredibly diverse, yet our knowledge of the morphogenetic behaviors that generate them is relatively limited. Recent studies have revealed unexpected mechanisms that drive axis elongation in the Drosophila egg, including an unconventional planar polarity signaling pathway, a distinctive type of morphogenetic movement termed "global tissue rotation," a molecular corset-like role of extracellular matrix, and oscillating basal cellular contractions. We review here what is known about Drosophila egg elongation, compare it to other instances of morphogenesis, and highlight several issues of general developmental relevance.
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Affiliation(s)
- David Bilder
- Department of Molecular & Cell Biology, 379 Life Sciences Addition #3200, University of California, Berkeley, Berkeley, CA 94720-3200, USA.
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81
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Wehman AM, Poggioli C, Schweinsberg P, Grant BD, Nance J. The P4-ATPase TAT-5 inhibits the budding of extracellular vesicles in C. elegans embryos. Curr Biol 2011; 21:1951-9. [PMID: 22100064 DOI: 10.1016/j.cub.2011.10.040] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 09/30/2011] [Accepted: 10/26/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Cells release extracellular vesicles (ECVs) that can influence differentiation, modulate the immune response, promote coagulation, and induce metastasis. Many ECVs form by budding outwards from the plasma membrane, but the molecules that regulate budding are unknown. In ECVs, the outer leaflet of the membrane bilayer contains aminophospholipids that are normally sequestered to the inner leaflet of the plasma membrane, suggesting a role for lipid asymmetry in ECV budding. RESULTS We show that loss of the conserved P4-ATPase TAT-5 causes the large-scale shedding of ECVs and disrupts cell adhesion and morphogenesis in Caenorhabditis elegans embryos. TAT-5 localizes to the plasma membrane and its loss results in phosphatidylethanolamine exposure on cell surfaces. We show that RAB-11 and endosomal sorting complex required for transport (ESCRT) proteins, which regulate the topologically analogous process of viral budding, are enriched at the plasma membrane in tat-5 embryos, and are required for ECV production. CONCLUSIONS TAT-5 is the first protein identified to regulate ECV budding. TAT-5 provides a potential molecular link between loss of phosphatidylethanolamine asymmetry and the dynamic budding of vesicles from the plasma membrane, supporting the hypothesis that lipid asymmetry regulates budding. Our results also suggest that viral budding and ECV budding may share common molecular mechanisms.
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Affiliation(s)
- Ann M Wehman
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
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82
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Abdus-Saboor I, Mancuso VP, Murray JI, Palozola K, Norris C, Hall DH, Howell K, Huang K, Sundaram MV. Notch and Ras promote sequential steps of excretory tube development in C. elegans. Development 2011; 138:3545-55. [PMID: 21771815 PMCID: PMC3143567 DOI: 10.1242/dev.068148] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2011] [Indexed: 12/31/2022]
Abstract
Receptor tyrosine kinases and Notch are crucial for tube formation and branching morphogenesis in many systems, but the specific cellular processes that require signaling are poorly understood. Here we describe sequential roles for Notch and Epidermal growth factor (EGF)-Ras-ERK signaling in the development of epithelial tube cells in the C. elegans excretory (renal-like) organ. This simple organ consists of three tandemly connected unicellular tubes: the excretory canal cell, duct and G1 pore. lin-12 and glp-1/Notch are required to generate the canal cell, which is a source of LIN-3/EGF ligand and physically attaches to the duct during de novo epithelialization and tubulogenesis. Canal cell asymmetry and let-60/Ras signaling influence which of two equivalent precursors will attach to the canal cell. Ras then specifies duct identity, inducing auto-fusion and a permanent epithelial character; the remaining precursor becomes the G1 pore, which eventually loses epithelial character and withdraws from the organ to become a neuroblast. Ras continues to promote subsequent aspects of duct morphogenesis and differentiation, and acts primarily through Raf-ERK and the transcriptional effectors LIN-1/Ets and EOR-1. These results reveal multiple genetically separable roles for Ras signaling in tube development, as well as similarities to Ras-mediated control of branching morphogenesis in more complex organs, including the mammalian kidney. The relative simplicity of the excretory system makes it an attractive model for addressing basic questions about how cells gain or lose epithelial character and organize into tubular networks.
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Affiliation(s)
- Ishmail Abdus-Saboor
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Vincent P. Mancuso
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - John I. Murray
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Katherine Palozola
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Carolyn Norris
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - David H. Hall
- Department of Neuroscience, Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kelly Howell
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Kai Huang
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Meera V. Sundaram
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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83
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Taniguchi K, Maeda R, Ando T, Okumura T, Nakazawa N, Hatori R, Nakamura M, Hozumi S, Fujiwara H, Matsuno K. Chirality in planar cell shape contributes to left-right asymmetric epithelial morphogenesis. Science 2011; 333:339-41. [PMID: 21764746 DOI: 10.1126/science.1200940] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Some organs in animals display left-right (LR) asymmetry. To better understand LR asymmetric morphogenesis in Drosophila, we studied LR directional rotation of the hindgut epithelial tube. Hindgut epithelial cells adopt a LR asymmetric (chiral) cell shape within their plane, and we refer to this cell behavior as planar cell-shape chirality (PCC). Drosophila E-cadherin (DE-Cad) is distributed to cell boundaries with LR asymmetry, which is responsible for the PCC formation. Myosin ID switches the LR polarity found in PCC and in DE-Cad distribution, which coincides with the direction of rotation. An in silico simulation showed that PCC is sufficient to induce the directional rotation of this tissue. Thus, the intrinsic chirality of epithelial cells in vivo is an underlying mechanism for LR asymmetric tissue morphogenesis.
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Affiliation(s)
- Kiichiro Taniguchi
- Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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84
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The branched actin nucleator Arp2/3 promotes nuclear migrations and cell polarity in the C. elegans zygote. Dev Biol 2011; 357:356-69. [PMID: 21798253 DOI: 10.1016/j.ydbio.2011.07.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/17/2011] [Accepted: 07/06/2011] [Indexed: 01/08/2023]
Abstract
Regulated movements of the nucleus are essential during zygote formation, cell migrations, and differentiation of neurons. The nucleus moves along microtubules (MTs) and is repositioned on F-actin at the cellular cortex. Two families of nuclear envelope proteins, SUN and KASH, link the nucleus to the actin and MT cytoskeletons during nuclear movements. However, the role of actin nucleators in nuclear migration and positioning is poorly understood. We show that the branched actin nucleator, Arp2/3, affects nuclear movements throughout embryonic and larval development in C. elegans, including nuclear migrations in epidermal cells and neuronal precursors. In one-cell embryos the migration of the male pronucleus to meet the female pronucleus after fertilization requires Arp2/3. Loss of Arp2/3 or its activators changes the dynamics of non-muscle myosin, NMY-2, and alters the cortical accumulation of posterior PAR proteins. Reduced establishment of the posterior microtubule cytoskeleton in Arp2/3 mutants correlates with reduced male pronuclear migration. The UNC-84/SUN nuclear envelope protein that links the nucleus to the MT and actin cytoskeleton is known to regulate later nuclear migrations. We show here it also positions the male pronucleus. These studies demonstrate a global role for Arp2/3 in nuclear migrations. In the C. elegans one-cell embryo Arp2/3 promotes the establishment of anterior/posterior polarity and promotes MT growth that propels the anterior migration of the male pronucleus. In contrast with previous studies emphasizing pulling forces on the male pronucleus, we propose that robust MT nucleation pushes the male pronucleus anteriorly to join the female pronucleus.
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Pohl C. Left-right patterning in the C. elegans embryo: Unique mechanisms and common principles. Commun Integr Biol 2011; 4:34-40. [PMID: 21509174 DOI: 10.4161/cib.4.1.14144] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 11/05/2010] [Indexed: 11/19/2022] Open
Abstract
The development of bilateral symmetry during the evolution of species probably 600 million years ago brought about several important innovations: It fostered efficient locomotion, streamlining and favored the development of a central nervous system through cephalization. However, to increase their functional capacities, many organisms exhibit chirality by breaking their superficial left-right (l-r) symmetry, which manifests in the lateralization of the nervous system or the l-r asymmetry of internal organs. In most bilateria, the mechanisms that maintain consistent l-r asymmetry throughout development are poorly understood. This review highlights insights into mechanisms that couple early embryonic l-r symmetry breaking to subsequent l-r patterning in the roundworm Caenorhabditis elegans. A recently identified strategy for l-r patterning in the early C. elegans embryo is discussed, the spatial separation of midline and anteroposterior axis, which relies on a rotational cellular rearrangement and non-canonical Wnt signaling. Evidence for a general relevance of rotational/torsional rearrangements during organismal l-r patterning and for non-canonical Wnt signaling/planar cell polarity as a common signaling mechanism to maintain l-r asymmetry is presented.
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Affiliation(s)
- Christian Pohl
- Developmental Biology Program; Sloan-Kettering Institute; New York, NY USA
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Micropatterned mammalian cells exhibit phenotype-specific left-right asymmetry. Proc Natl Acad Sci U S A 2011; 108:12295-300. [PMID: 21709270 DOI: 10.1073/pnas.1103834108] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Left-right (LR) asymmetry (handedness, chirality) is a well-conserved biological property of critical importance to normal development. Changes in orientation of the LR axis due to genetic or environmental factors can lead to malformations and disease. While the LR asymmetry of organs and whole organisms has been extensively studied, little is known about the LR asymmetry at cellular and multicellular levels. Here we show that the cultivation of cell populations on micropatterns with defined boundaries reveals intrinsic cell chirality that can be readily determined by image analysis of cell alignment and directional motion. By patterning 11 different types of cells on ring-shaped micropatterns of various sizes, we found that each cell type exhibited definite LR asymmetry (p value down to 10(-185)) that was different between normal and cancer cells of the same type, and not dependent on surface chemistry, protein coating, or the orientation of the gravitational field. Interestingly, drugs interfering with actin but not microtubule function reversed the LR asymmetry in some cell types. Our results show that micropatterned cell populations exhibit phenotype-specific LR asymmetry that is dependent on the functionality of the actin cytoskeleton. We propose that micropatterning could potentially be used as an effective in vitro tool to study the initiation of LR asymmetry in cell populations, to diagnose disease, and to study factors involved with birth defects in laterality.
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