1
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Song J, Evans EJ, Dallon JC. Differential cell motion: A mathematical model of anterior posterior sorting. Biophys J 2023; 122:4160-4175. [PMID: 37752701 PMCID: PMC10645555 DOI: 10.1016/j.bpj.2023.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 08/17/2023] [Accepted: 09/20/2023] [Indexed: 09/28/2023] Open
Abstract
Here, we investigate how a subpopulation of cells can move through an aggregate of cells. Using a stochastic force-based model of Dictyostelium discoideum when the population is forming a slug, we simulate different strategies for prestalk cells to reliably move to the front of the slug while omitting interaction with the substrate thus ignoring the overall motion of the slug. Of the mechanisms that we simulated, prestalk cells being more directed is the best strategy followed by increased asymmetric motive forces for prestalk cells. The lifetime of the cell adhesion molecules, while not enough to produce differential motion, did modulate the results of the strategies employed. Finally, understanding and simulating the appropriate boundary conditions are essential to correctly predict the motion.
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Affiliation(s)
- Joy Song
- Department of Mathematics, Brigham Young University, Provo, Utah
| | - Emily J Evans
- Department of Mathematics, Brigham Young University, Provo, Utah
| | - J C Dallon
- Department of Mathematics, Brigham Young University, Provo, Utah.
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2
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Ricci-Tam C, Kuipa S, Kostman MP, Aronson MS, Sgro AE. Microbial models of development: Inspiration for engineering self-assembled synthetic multicellularity. Semin Cell Dev Biol 2023; 141:50-62. [PMID: 35537929 DOI: 10.1016/j.semcdb.2022.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/13/2022] [Indexed: 10/18/2022]
Abstract
While the field of synthetic developmental biology has traditionally focused on the study of the rich developmental processes seen in metazoan systems, an attractive alternate source of inspiration comes from microbial developmental models. Microbes face unique lifestyle challenges when forming emergent multicellular collectives. As a result, the solutions they employ can inspire the design of novel multicellular systems. In this review, we dissect the strategies employed in multicellular development by two model microbial systems: the cellular slime mold Dictyostelium discoideum and the biofilm-forming bacterium Bacillus subtilis. Both microbes face similar challenges but often have different solutions, both from metazoan systems and from each other, to create emergent multicellularity. These challenges include assembling and sustaining a critical mass of participating individuals to support development, regulating entry into development, and assigning cell fates. The mechanisms these microbial systems exploit to robustly coordinate development under a wide range of conditions offer inspiration for a new toolbox of solutions to the synthetic development community. Additionally, recreating these phenomena synthetically offers a pathway to understanding the key principles underlying how these behaviors are coordinated naturally.
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Affiliation(s)
- Chiara Ricci-Tam
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Sophia Kuipa
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Maya Peters Kostman
- Biological Design Center, Boston University, Boston, MA 02215, USA; Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, MA 02215, USA
| | - Mark S Aronson
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA
| | - Allyson E Sgro
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Biological Design Center, Boston University, Boston, MA 02215, USA; Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, MA 02215, USA.
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3
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Saito T, Iijima T, Koyama K, Shinagawa T, Yamanaka A, Araki T, Suzuki N, Usuki T, Kay RR. Generating polyketide diversity in Dictyostelium: a Steely hybrid polyketide synthase produces alternate products at different developmental stages. Proc Biol Sci 2022; 289:20221176. [PMID: 36126683 PMCID: PMC9489281 DOI: 10.1098/rspb.2022.1176] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The soil is a rich ecosystem where many ecological interactions are mediated by small molecules, and in which amoebae are low-level predators and also prey. The social amoeba Dictyostelium discoideum has a high genomic potential for producing polyketides to mediate its ecological interactions, including the unique 'Steely' enzymes, consisting of a fusion between a fatty acid synthase and a chalcone synthase. We report here that D. discoideum further increases its polyketide potential by using the StlB Steely enzyme, and a downstream chlorinating enzyme, to make both a chlorinated signal molecule, DIF-1, during its multi-cellular development, and a set of abundant polyketides in terminally differentiated stalk cells. We identify one of these as a chlorinated dibenzofuran with potent anti-bacterial activity. To do this, StlB switches expression from prespore to stalk cells in late development and is cleaved to release the chalcone synthase domain. Expression of this domain alone in StlB null cells allows synthesis of the stalk-associated, chlorinated polyketides. Thus, by altered expression and processing of StlB, cells make first a signal molecule, and then abundant secondary metabolites, which we speculate help to protect the mature spores from bacterial infection.
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Affiliation(s)
- Tamao Saito
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tomoyuki Iijima
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Kohei Koyama
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tomonori Shinagawa
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Ayaka Yamanaka
- Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Tsuyoshi Araki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Noriyuki Suzuki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Toyonobu Usuki
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
| | - Robert R. Kay
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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4
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Hiraoka H, Wang J, Nakano T, Hirano Y, Yamazaki S, Hiraoka Y, Haraguchi T. ATP levels influence cell movement during the mound phase in Dictyostelium discoideum as revealed by ATP visualization and simulation. FEBS Open Bio 2022; 12:2042-2056. [PMID: 36054629 PMCID: PMC9623536 DOI: 10.1002/2211-5463.13480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 01/25/2023] Open
Abstract
Cell migration plays an important role in multicellular organism development. The cellular slime mold Dictyostelium discoideum is a useful model organism for the study of cell migration during development. Although cellular ATP levels are known to determine cell fate during development, the underlying mechanism remains unclear. Here, we report that ATP-rich cells efficiently move to the central tip region of the mound against rotational movement during the mound phase. A simulation analysis based on an agent-based model reproduces the movement of ATP-rich cells observed in the experiments. These findings indicate that ATP-rich cells have the ability to move against the bulk flow of cells, suggesting a mechanism by which high ATP levels determine the cell fate of differentiation.
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Affiliation(s)
- Haruka Hiraoka
- Graduate School of Frontier BiosciencesOsaka UniversityJapan,Graduate School of ScienceNagoya UniversityJapan
| | - Jiewen Wang
- Graduate School of InformaticsOsaka Metropolitan UniversityJapan
| | - Tadashi Nakano
- Graduate School of InformaticsOsaka Metropolitan UniversityJapan
| | - Yasuhiro Hirano
- Graduate School of Frontier BiosciencesOsaka UniversityJapan
| | | | - Yasushi Hiraoka
- Graduate School of Frontier BiosciencesOsaka UniversityJapan
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5
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Feng J, Hsu WH, Patterson D, Tseng CS, Hsing HW, Zhuang ZH, Huang YT, Faedo A, Rubenstein JL, Touboul J, Chou SJ. COUP-TFI specifies the medial entorhinal cortex identity and induces differential cell adhesion to determine the integrity of its boundary with neocortex. SCIENCE ADVANCES 2021; 7:eabf6808. [PMID: 34215582 PMCID: PMC11057786 DOI: 10.1126/sciadv.abf6808] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/12/2021] [Indexed: 06/13/2023]
Abstract
Development of cortical regions with precise, sharp, and regular boundaries is essential for physiological function. However, little is known of the mechanisms ensuring these features. Here, we show that determination of the boundary between neocortex and medial entorhinal cortex (MEC), two abutting cortical regions generated from the same progenitor lineage, relies on COUP-TFI (chicken ovalbumin upstream promoter-transcription factor I), a patterning transcription factor with graded expression in cortical progenitors. In contrast with the classical paradigm, we found that increased COUP-TFI expression expands MEC, creating protrusions and disconnected ectopic tissue. We further developed a mathematical model that predicts that neuronal specification and differential cell affinity contribute to the emergence of an instability region and boundary sharpness. Correspondingly, we demonstrated that high expression of COUP-TFI induces MEC cell fate and protocadherin 19 expression. Thus, we conclude that a sharp boundary requires a subtle interplay between patterning transcription factors and differential cell affinity.
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Affiliation(s)
- Jia Feng
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Wen-Hsin Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Denis Patterson
- Department of Mathematics and Volen National Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | - Ching-San Tseng
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Hsiang-Wei Hsing
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Zi-Hui Zhuang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ting Huang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Andrea Faedo
- Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - John L Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonathan Touboul
- Department of Mathematics and Volen National Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | - Shen-Ju Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
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6
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Saiz N, Hadjantonakis AK. Coordination between patterning and morphogenesis ensures robustness during mouse development. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190562. [PMID: 32829684 PMCID: PMC7482220 DOI: 10.1098/rstb.2019.0562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2020] [Indexed: 12/11/2022] Open
Abstract
The mammalian preimplantation embryo is a highly tractable, self-organizing developmental system in which three cell types are consistently specified without the need for maternal factors or external signals. Studies in the mouse over the past decades have greatly improved our understanding of the cues that trigger symmetry breaking in the embryo, the transcription factors that control lineage specification and commitment, and the mechanical forces that drive morphogenesis and inform cell fate decisions. These studies have also uncovered how these multiple inputs are integrated to allocate the right number of cells to each lineage despite inherent biological noise, and as a response to perturbations. In this review, we summarize our current understanding of how these processes are coordinated to ensure a robust and precise developmental outcome during early mouse development. This article is part of a discussion meeting issue 'Contemporary morphogenesis'.
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Affiliation(s)
- Néstor Saiz
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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7
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Libby ARG, Briers D, Haghighi I, Joy DA, Conklin BR, Belta C, McDevitt TC. Automated Design of Pluripotent Stem Cell Self-Organization. Cell Syst 2019; 9:483-495.e10. [PMID: 31759947 PMCID: PMC7089762 DOI: 10.1016/j.cels.2019.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 07/17/2019] [Accepted: 10/23/2019] [Indexed: 11/20/2022]
Abstract
Human pluripotent stem cells (hPSCs) have the intrinsic ability to self-organize into complex multicellular organoids that recapitulate many aspects of tissue development. However, robustly directing morphogenesis of hPSC-derived organoids requires novel approaches to accurately control self-directed pattern formation. Here, we combined genetic engineering with computational modeling, machine learning, and mathematical pattern optimization to create a data-driven approach to control hPSC self-organization by knock down of genes previously shown to affect stem cell colony organization, CDH1 and ROCK1. Computational replication of the in vitro system in silico using an extended cellular Potts model enabled machine learning-driven optimization of parameters that yielded emergence of desired patterns. Furthermore, in vitro the predicted experimental parameters quantitatively recapitulated the in silico patterns. These results demonstrate that morphogenic dynamics can be accurately predicted through model-driven exploration of hPSC behaviors via machine learning, thereby enabling spatial control of multicellular patterning to engineer human organoids and tissues. A record of this paper's Transparent Peer Review process is included in the Supplemental Information.
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Affiliation(s)
- Ashley R G Libby
- Developmental and Stem Cell Biology PhD Program, University of California, San Francisco, San Francisco, CA, USA; Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA
| | | | - Iman Haghighi
- Systems Engineering Department at Boston University, Boston, MA, USA
| | - David A Joy
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA; UC Berkeley-UC San Francisco Bioengineering Graduate Program, San Francisco, CA, USA
| | - Bruce R Conklin
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA; Departments of Medicine, Pharmacology, and Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Calin Belta
- Systems Engineering Department at Boston University, Boston, MA, USA.
| | - Todd C McDevitt
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA.
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8
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Fujimori T, Nakajima A, Shimada N, Sawai S. Tissue self-organization based on collective cell migration by contact activation of locomotion and chemotaxis. Proc Natl Acad Sci U S A 2019; 116:4291-4296. [PMID: 30782791 PMCID: PMC6410881 DOI: 10.1073/pnas.1815063116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite their central role in multicellular organization, navigation rules that dictate cell rearrangement remain largely undefined. Contact between neighboring cells and diffusive attractant molecules are two of the major determinants of tissue-level patterning; however, in most cases, molecular and developmental complexity hinders one from decoding the exact governing rules of individual cell movement. A primordial example of tissue patterning by cell rearrangement is found in the social amoeba Dictyostelium discoideum where the organizing center or the "tip" self-organizes as a result of sorting of differentiating prestalk and prespore cells. By employing microfluidics and microsphere-based manipulation of navigational cues at the single-cell level, here we uncovered a previously overlooked mode of Dictyostelium cell migration that is strictly directed by cell-cell contact. The cell-cell contact signal is mediated by E-set Ig-like domain-containing heterophilic adhesion molecules TgrB1/TgrC1 that act in trans to induce plasma membrane recruitment of the SCAR complex and formation of dendritic actin networks, and the resulting cell protrusion competes with those induced by chemoattractant cAMP. Furthermore, we demonstrate that both prestalk and prespore cells can protrude toward the contact signal as well as to chemotax toward cAMP; however, when given both signals, prestalk cells orient toward the chemoattractant, whereas prespore cells choose the contact signal. These data suggest a model of cell sorting by competing juxtacrine and diffusive cues, each with potential to drive its own mode of collective cell migration.
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Affiliation(s)
- Taihei Fujimori
- Graduate School of Arts and Sciences, University of Tokyo, Komaba, 153-8902 Tokyo, Japan
| | - Akihiko Nakajima
- Graduate School of Arts and Sciences, University of Tokyo, Komaba, 153-8902 Tokyo, Japan
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Komaba, 153-8902 Tokyo, Japan
| | - Nao Shimada
- Graduate School of Arts and Sciences, University of Tokyo, Komaba, 153-8902 Tokyo, Japan
| | - Satoshi Sawai
- Graduate School of Arts and Sciences, University of Tokyo, Komaba, 153-8902 Tokyo, Japan;
- Research Center for Complex Systems Biology, Universal Biology Institute, University of Tokyo, Komaba, 153-8902 Tokyo, Japan
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9
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Trenchard H. Cell pelotons: A model of early evolutionary cell sorting, with application to slime mold Dictyostelium discoideum. J Theor Biol 2019; 469:75-95. [PMID: 30794840 DOI: 10.1016/j.jtbi.2019.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 01/29/2019] [Accepted: 02/19/2019] [Indexed: 11/19/2022]
Abstract
A theoretical model is presented for early evolutionary cell sorting within cellular aggregates. The model involves an energy-saving mechanism and principles of collective self-organization analogous to those observed in bicycle pelotons (groups of cyclists). The theoretical framework is applied to slime-mold slugs (Dictyostelium discoideum) and incorporated into a computer simulation which demonstrates principally the sorting of cells between the anterior and posterior slug regions. The simulation relies on an existing simulation of bicycle peloton dynamics which is modified to incorporate a limited range of cell metabolic capacities among heterogeneous cells, along with a tunable energy-expenditure parameter, referred to as an "output-level" or "starvation-level" to reflect diminishing energetic supply. Proto-cellular dynamics are modeled for three output phases: "active", "suffering", and "dying or dead." Adjusting the starvation parameter causes cell differentiation and sorting into sub-groups within the cellular aggregate. Tuning of the starvation parameter demonstrates how weak or expired cells shuffle backward within the cellular aggregate.
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Affiliation(s)
- Hugh Trenchard
- Independent Researcher, 805 647 Michigan Street, Victoria, BC V8V 1S9, Canada.
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10
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Kondo AP, Narita TB, Murata C, Ogura T, Mikagi A, Usuki T, Saito T. 4-Methyl-5-Pentylbenzene-1,3-Diol Regulates Chemotactic Cell Aggregation and Spore Maturation Via Different Mechanisms in Dictyostelium discoideum. Curr Microbiol 2019; 76:376-381. [PMID: 30710153 DOI: 10.1007/s00284-019-01639-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/21/2019] [Indexed: 11/25/2022]
Abstract
4-Methyl-5-pentylbenzene-1,3-diol (MPBD), a product of the polyketide synthase SteelyA, is a signaling molecule that regulates Dictyostelium discoideum development. During early development, MPBD controls chemotactic cell aggregation by regulating the expression of genes in the cAMP signaling pathway; however, during culmination at late development, it induces spore maturation. In the present study, we analyzed the effects of MPBD, its derivatives, and a putative MPBD-derived metabolite on developmental defects in the MPBD-less stlA null mutant. Using structure-activity relationship studies, it was observed that in MPBD, the functional groups that were essential for induction of spore maturation were different from those essential for induction of cell aggregation. Dictyoquinone, a putative MPBD metabolite rescued the aggregation defect in stlA null mutant in early development, but not the spore maturation defect at the later stage. Our data suggest that MPBD regulates chemotactic cell aggregation and spore maturation via different mechanisms.
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Affiliation(s)
- Anna P Kondo
- Graduate School of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Takaaki B Narita
- Graduate School of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
- Faculty of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Chihiro Murata
- Graduate School of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Tetsuhiro Ogura
- Graduate School of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Ayame Mikagi
- Graduate School of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Toyonobu Usuki
- Faculty of Science and Technology, Sophia University, Tokyo, 102-8554, Japan
| | - Tamao Saito
- Faculty of Science and Technology, Sophia University, Tokyo, 102-8554, Japan.
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11
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Saito YF, Miyazaki SH, Bartlem DG, Nagamatsu Y, Saito T. Chemical compounds from Dictyostelium discoideum repel a plant-parasitic nematode and can protect roots. PLoS One 2018; 13:e0204671. [PMID: 30261017 PMCID: PMC6160129 DOI: 10.1371/journal.pone.0204671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 09/12/2018] [Indexed: 11/18/2022] Open
Abstract
Slime mold species in the genus Dictyostelium are considered to have a close relationship with non-parasitic nematodes; they are sympatric in soils and can exhibit interspecific competition for food. We investigated whether this relationship extends to a plant-parasitic nematode that is active in the rhizosphere and has broad host specificity, damaging crops worldwide. Using a novel assay to examine the interaction between the cellular slime mold, Dictyostelium discoideum, and the plant-parasitic nematodes, Meloidogyne spp., we found that cellular slime molds can repel plant parasitic nematodes. Specifically, the repulsion activity was in response to chemical compounds released by cellular slime mold fruiting bodies. Under laboratory conditions, these soluble chemical extracts from fruiting bodies of D. discoideum showed repulsion activity strong enough to protect plant roots. The fruiting body cell extracts repelled but were not toxic to the plant-parasitic nematodes.
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Affiliation(s)
- Yumiko F. Saito
- Graduate School of Science and Technology, Sophia University, Tokyo, Japan
| | - Saki H. Miyazaki
- Graduate School of Science and Technology, Sophia University, Tokyo, Japan
| | - Derek G. Bartlem
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yukiko Nagamatsu
- Institute of Environmental Science, Panefri Industrial Company, Okinawa, Japan
| | - Tamao Saito
- Faculty of Science and Technology, Sophia University, Tokyo, Japan
- * E-mail:
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12
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Wood S, Loudon A. The pars tuberalis: The site of the circannual clock in mammals? Gen Comp Endocrinol 2018; 258:222-235. [PMID: 28669798 DOI: 10.1016/j.ygcen.2017.06.029] [Citation(s) in RCA: 38] [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] [Received: 05/02/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
Accurate timing and physiological adaptation to anticipate seasonal changes are an essential requirement for an organism's survival. In contrast to all other environmental cues, photoperiod offers a highly predictive signal that can be reliably used to activate a seasonal adaptive programme at the correct time of year. Coupled to photoperiod sensing, it is apparent that many organisms have evolved innate long-term timekeeping systems, allowing reliable anticipation of forthcoming environmental changes. The fundamental biological processes giving rise to innate long-term timing, with which the photoperiod-sensing pathway engages, are not known for any organism. There is growing evidence that the pars tuberalis (PT) of the pituitary, which acts as a primary transducer of photoperiodic input, may be the site of the innate long-term timer or "circannual clock". Current research has led to the proposition that the PT-specific thyrotroph may act as a seasonal calendar cell, driving both hypothalamic and pituitary endocrine circuits. Based on this research we propose that the mechanistic basis for the circannual rhythm appears to be deeply conserved, driven by a binary switching cell based accumulator, analogous to that proposed for development. We review the apparent conservation of function and pathways to suggest that these broad principles may apply across the vertebrate lineage and even share characteristics with processes driving seasonal adaptation in plants.
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Affiliation(s)
- Shona Wood
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK.
| | - Andrew Loudon
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK
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13
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Narita TB, Schaap P, Saito T. Effects of deletion of the receptor CrlA on Dictyostelium aggregation and MPBD-mediated responses are strain dependent and not evident in strain Ax2. FEMS Microbiol Lett 2017; 364:2966322. [PMID: 28158557 DOI: 10.1093/femsle/fnx022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/24/2017] [Indexed: 11/14/2022] Open
Abstract
The polyketide MPBD (4-methyl-5-pentylbenzene-1, 3-diol) is produced by the polyketide synthase SteelyA (StlA) in Dictyostelium discoideum. MPBD is required for appropriate expression of cAMP signalling genes involved in cell aggregation and additionally induces the spore maturation at the fruiting body stage. The MPBD signalling pathway for regulation of cell aggregation is unknown, but MPBD effects on sporulation were reported to be mediated by the G-protein coupled receptor CrlA in D. discoideum KAx3. In this study, we deleted the crlA gene from the same parental strain (Ax2) that was used to generate the MPBD-less mutant. We found that unlike the MPBD-less mutant, Ax2-derived crlA- mutants exhibited normal cell aggregation, indicating that in Ax2 MPBD effects on early development do not require CrlA. We also found that the Ax2/crlA- mutant formed normal spores in fruiting bodies. When transformed with PkaC, both Ax2 and Ax2/crlA- similarly responded to MPBD in vitro with spore encapsulation. Our data make it doubtful that CrlA acts as the receptor for MPBD signalling during the development of D. discoideum Ax2.
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Affiliation(s)
- Takaaki B Narita
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan.,School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Pauline Schaap
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Tamao Saito
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan
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14
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Wang Q, Holmes WR, Sosnik J, Schilling T, Nie Q. Cell Sorting and Noise-Induced Cell Plasticity Coordinate to Sharpen Boundaries between Gene Expression Domains. PLoS Comput Biol 2017; 13:e1005307. [PMID: 28135279 PMCID: PMC5279720 DOI: 10.1371/journal.pcbi.1005307] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/09/2016] [Indexed: 12/13/2022] Open
Abstract
A fundamental question in biology is how sharp boundaries of gene expression form precisely in spite of biological variation/noise. Numerous mechanisms position gene expression domains across fields of cells (e.g. morphogens), but how these domains are refined remains unclear. In some cases, domain boundaries sharpen through differential adhesion-mediated cell sorting. However, boundaries can also sharpen through cellular plasticity, with cell fate changes driven by up- or down-regulation of gene expression. In this context, we have argued that noise in gene expression can help cells transition to the correct fate. Here we investigate the efficacy of cell sorting, gene expression plasticity, and their combination in boundary sharpening using multi-scale, stochastic models. We focus on the formation of hindbrain segments (rhombomeres) in the developing zebrafish as an example, but the mechanisms investigated apply broadly to many tissues. Our results indicate that neither sorting nor plasticity is sufficient on its own to sharpen transition regions between different rhombomeres. Rather the two have complementary strengths and weaknesses, which synergize when combined to sharpen gene expression boundaries. In many developing systems, chemical gradients control the formation of segmental domains of gene expression, specifying distinct domains that go on to form different tissues and structures, in a concentration-dependent manner. These gradients are noisy however, raising the question of how sharply delineated boundaries between distinct segments form. It is crucial that developing systems be able to cope with stochasticity and generate well-defined boundaries between different segmented domains. Previous work suggests that cell sorting and cellular plasticity help sharpen boundaries between segments. However, it remains unclear how effective each of these mechanisms is and what their role in sharpening may be. Motivated by recent experimental observations, we construct a hybrid stochastic model to investigate these questions. We find that neither mechanism is sufficient on its own to sharpen boundaries between different segments. Rather, results indicate each has its own strengths and weaknesses, and that they work together synergistically to promote the development of precise, well defined segment boundaries. Formation of segmented rhombomeres in the zebrafish hindbrain, which later form different components of the central nervous system, is a motivating case for this study.
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Affiliation(s)
- Qixuan Wang
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, United States of America
- Department of Mathematics, University of California Irvine, Irvine, CA, United States of America
| | - William R. Holmes
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, United States of America
| | - Julian Sosnik
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, United States of America
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, United States of America
| | - Thomas Schilling
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, United States of America
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, United States of America
| | - Qing Nie
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, United States of America
- Department of Mathematics, University of California Irvine, Irvine, CA, United States of America
- * E-mail:
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McGuigan AP, Javaherian S. Tissue Patterning: Translating Design Principles from In Vivo to In Vitro. Annu Rev Biomed Eng 2016; 18:1-24. [DOI: 10.1146/annurev-bioeng-083115-032943] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Alison P. McGuigan
- Department of Chemical Engineering and Applied Chemistry and
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3E5, Canada;
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Gordon NK, Gordon R. The organelle of differentiation in embryos: the cell state splitter. Theor Biol Med Model 2016; 13:11. [PMID: 26965444 PMCID: PMC4785624 DOI: 10.1186/s12976-016-0037-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/27/2016] [Indexed: 12/16/2022] Open
Abstract
The cell state splitter is a membraneless organelle at the apical end of each epithelial cell in a developing embryo. It consists of a microfilament ring and an intermediate filament ring subtending a microtubule mat. The microtubules and microfilament ring are in mechanical opposition as in a tensegrity structure. The cell state splitter is bistable, perturbations causing it to contract or expand radially. The intermediate filament ring provides metastability against small perturbations. Once this snap-through organelle is triggered, it initiates signal transduction to the nucleus, which changes gene expression in one of two readied manners, causing its cell to undergo a step of determination and subsequent differentiation. The cell state splitter also triggers the cell state splitters of adjacent cells to respond, resulting in a differentiation wave. Embryogenesis may be represented then as a bifurcating differentiation tree, each edge representing one cell type. In combination with the differentiation waves they propagate, cell state splitters explain the spatiotemporal course of differentiation in the developing embryo. This review is excerpted from and elaborates on "Embryogenesis Explained" (World Scientific Publishing, Singapore, 2016).
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Affiliation(s)
| | - Richard Gordon
- />Retired, University of Manitoba, Winnipeg, Canada
- />Embryogenesis Center, Gulf Specimen Aquarium & Marine Laboratory, 222 Clark Drive, Panacea, FL 32346 USA
- />C.S. Mott Center for Human Growth & Development, Department of Obstetrics & Gynecology, Wayne State University, 275 E. Hancock, Detroit, MI 48201 USA
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17
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Patterning of the angiosperm female gametophyte through the prism of theoretical paradigms. Biochem Soc Trans 2015; 42:332-9. [PMID: 24646240 DOI: 10.1042/bst20140036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The FG (female gametophyte) of flowering plants (angiosperms) is a simple highly polar structure composed of only a few cell types. The FG develops from a single cell through mitotic divisions to generate, depending on the species, four to 16 nuclei in a syncytium. These nuclei are then partitioned into three or four distinct cell types. The mechanisms underlying the specification of the nuclei in the FG has been a focus of research over the last decade. Nevertheless, we are far from understanding the patterning mechanisms that govern cell specification. Although some results were previously interpreted in terms of static positional information, several lines of evidence now show that local interactions are important. In the present article, we revisit the available data on developmental mutants and cell fate markers in the light of theoretical frameworks for biological patterning. We argue that a further dissection of the mechanisms may be impeded by the combinatorial and dynamical nature of developmental cues. However, accounting for these properties of developing systems is necessary to disentangle the diversity of the phenotypic manifestations of the underlying molecular interactions.
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Pineda M, Weijer CJ, Eftimie R. Modelling cell movement, cell differentiation, cell sorting and proportion regulation in Dictyostelium discoideum aggregations. J Theor Biol 2015; 370:135-50. [PMID: 25665718 DOI: 10.1016/j.jtbi.2015.01.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 11/27/2014] [Accepted: 01/27/2015] [Indexed: 11/25/2022]
Abstract
Understanding the mechanisms that control tissue morphogenesis and homeostasis is a central goal not only in developmental biology but also has great relevance for our understanding of various diseases, including cancer. A model organism that is widely used to study the control of tissue morphogenesis and proportioning is the Dictyostelium discoideum. While there are mathematical models describing the role of chemotactic cell motility in the Dictyostelium assembly and morphogenesis of multicellular tissues, as well as models addressing possible mechanisms of proportion regulation, there are no models incorporating both these key aspects of development. In this paper, we introduce a 1D hyperbolic model to investigate the role of two morphogens, DIF and cAMP, on cell movement, cell sorting, cell-type differentiation and proportioning in Dictyostelium discoideum. First, we use the non-spatial version of the model to study cell-type transdifferentiation. We perform a steady-state analysis of it and show that, depending on the shape of the differentiation rate functions, multiple steady-state solutions may occur. Then we incorporate spatial dynamics into the model, and investigate the transdifferentiation and spatial positioning of cells inside the newly formed structures, following the removal of prestalk or prespore regions of a Dictyostelium slug. We show that in isolated prespore fragments, a tipped mound-like aggregate can be formed after a transdifferentiation from prespore to prestalk cells and following the sorting of prestalk cells to the centre of the aggregate. For isolated prestalk fragments, we show the formation of a slug-like structure containing the usual anterior-posterior pattern of prestalk and prespore cells.
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Affiliation(s)
- M Pineda
- Division of Mathematics, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - C J Weijer
- School of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom.
| | - R Eftimie
- Division of Mathematics, University of Dundee, Dundee DD1 4HN, United Kingdom.
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Evolutionary reconstruction of pattern formation in 98 Dictyostelium species reveals that cell-type specialization by lateral inhibition is a derived trait. EvoDevo 2014; 5:34. [PMID: 25904998 PMCID: PMC4406040 DOI: 10.1186/2041-9139-5-34] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/22/2014] [Indexed: 02/07/2023] Open
Abstract
Background Multicellularity provides organisms with opportunities for cell-type specialization, but requires novel mechanisms to position correct proportions of different cell types throughout the organism. Dictyostelid social amoebas display an early form of multicellularity, where amoebas aggregate to form fruiting bodies, which contain only spores or up to four additional cell-types. These cell types will form the stalk and support structures for the stalk and spore head. Phylogenetic inference subdivides Dictyostelia into four major groups, with the model organism D. discoideum residing in group 4. In D. discoideum differentiation of its five cell types is dominated by lateral inhibition-type mechanisms that trigger scattered cell differentiation, with tissue patterns being formed by cell sorting. Results To reconstruct the evolution of pattern formation in Dictyostelia, we used cell-type specific antibodies and promoter-reporter fusion constructs to investigate pattern formation in 98 species that represent all groupings. Our results indicate that in all early diverging Dictyostelia and most members of groups 1–3, cells differentiate into maximally two cell types, prestalk and prespore cells, with pattern formation being dominated by position-dependent transdifferentiation of prespore cells into prestalk cells. In clade 2A, prestalk and stalk cell differentiation are lost and the prespore cells construct an acellular stalk. Group 4 species set aside correct proportions of prestalk and prespore cells early in development, and differentiate into up to three more supporting cell types. Conclusions Our experiments show that positional transdifferentiation is the ancestral mode of pattern formation in Dictyostelia. The early specification of a prestalk population equal to the number of stalk cells is a derived trait that emerged in group 4 and a few late diverging species in the other groups. Group 4 spore masses are larger than those of other groups and the differentiation of supporting cell types by lateral inhibition may have facilitated this increase in size. The signal DIF-1, which is secreted by prespore cells, triggers differentiation of supporting cell types. The synthesis and degradation of DIF-1 were shown to be restricted to group 4. This suggests that the emergence of DIF-1 signalling caused increased cell-type specialization in this group. Electronic supplementary material The online version of this article (doi:10.1186/2041-9139-5-34) contains supplementary material, which is available to authorized users.
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Narita TB, Chen ZH, Schaap P, Saito T. The hybrid type polyketide synthase SteelyA is required for cAMP signalling in early Dictyostelium development. PLoS One 2014; 9:e106634. [PMID: 25222736 PMCID: PMC4164351 DOI: 10.1371/journal.pone.0106634] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 08/08/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In our previous study we found that the expression of stlA showed peaks both in the early and last stages of development and that a product of SteelyA, 4-methyl-5-pentylbenzene-1,3-diol (MPBD), controlled Dictyostelium spore maturation during the latter. In this study we focused on the role of SteelyA in early stage development. PRINCIPAL FINDINGS Our stlA null mutant showed aggregation delay and abnormally small aggregation territories. Chemotaxis analysis revealed defective cAMP chemotaxis in the stlA null mutant. cAMP chemotaxis was restored by MPBD addition during early stage development. Assay for cAMP relay response revealed that the stlA null mutant had lower cAMP accumulation during aggregation, suggesting lower ACA activity than the wild type strain. Exogenous cAMP pulses rescued the aggregation defect of the stlA null strain in the absence of MPBD. Expression analysis of cAMP signalling genes revealed lower expression levels in the stlA null mutant during aggregation. CONCLUSION Our data indicate a regulatory function by SteelyA on cAMP signalling during aggregation and show that SteelyA is indispensable for full activation of ACA.
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Affiliation(s)
- Takaaki B. Narita
- Graduate School of Science and Technology, Sophia University, Tokyo, Japan
- Research Fellow of Japan Society for the Promotion of Science (DC2), Tokyo, Japan
| | - Zhi-hui Chen
- College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Pauline Schaap
- College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Tamao Saito
- Department of Materials and Life Sciences, Sophia University, Tokyo, Japan
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Cell-to-cell expression variability followed by signal reinforcement progressively segregates early mouse lineages. Nat Cell Biol 2013; 16:27-37. [PMID: 24292013 PMCID: PMC4062977 DOI: 10.1038/ncb2881] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 10/18/2013] [Indexed: 12/13/2022]
Abstract
It is now recognized that extensive expression heterogeneities among cells precede the emergence of lineages in the early mammalian embryo. To establish a map of pluripotent epiblast (EPI) versus primitive endoderm (PrE) lineage segregation within the inner cell mass (ICM) of the mouse blastocyst, we characterised the gene expression profiles of individual ICM cells. Clustering analysis of the transcriptomes of 66 cells demonstrated that initially they are non-distinguishable. Early in the segregation, lineage-specific marker expression exhibited no apparent correlation, and a hierarchical relationship was established only in the late blastocyst. Fgf4 exhibited a bimodal expression at the earliest stage analysed, and in its absence, the differentiation of PrE and EPI was halted, indicating that Fgf4 drives, and is required for, ICM lineage segregation. These data lead us to propose a model where stochastic cell-to-cell expression heterogeneity followed by signal reinforcement underlies ICM lineage segregation by antagonistically separating equivalent cells.
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Chattwood A, Nagayama K, Bolourani P, Harkin L, Kamjoo M, Weeks G, Thompson CRL. Developmental lineage priming in Dictyostelium by heterogeneous Ras activation. eLife 2013; 2:e01067. [PMID: 24282234 PMCID: PMC3838634 DOI: 10.7554/elife.01067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In cell culture, genetically identical cells often exhibit heterogeneous behavior, with only 'lineage primed' cells responding to differentiation inducing signals. It has recently been proposed that such heterogeneity exists during normal embryonic development to allow position independent patterning based on 'salt and pepper' differentiation and sorting out. However, the molecular basis of lineage priming and how it leads to reproducible cell type proportioning are poorly understood. To address this, we employed a novel forward genetic approach in the model organism Dictyostelium discoideum. These studies reveal that the Ras-GTPase regulator gefE is required for normal lineage priming and salt and pepper differentiation. This is because Ras-GTPase activity sets the intrinsic response threshold to lineage specific differentiation signals. Importantly, we show that although gefE expression is uniform, transcription of its target, rasD, is both heterogeneous and dynamic, thus providing a novel mechanism for heterogeneity generation and position-independent differentiation. DOI: http://dx.doi.org/10.7554/eLife.01067.001.
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Affiliation(s)
- Alex Chattwood
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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23
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Steely enzymes are involved in prestalk and prespore pattern formation. Biosci Biotechnol Biochem 2013; 77:2008-12. [PMID: 24096661 DOI: 10.1271/bbb.130294] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
4-Methyl-5-pentylbenzene-1,3-diol (MPBD), a product of SteelyA enzyme, controls Dictyostelium spore maturation. Since the expression of stlA split the in early and terminal stages, we cannot exclude the possibility that MPBD regulates spore differentiation from the early stage by creating a bias between the cells. 1-(3,5-Dichloro-2,6-dihydroxy-4-methoxyphenyl) hexan-1-on (DIF-1), a product of SteelyB, was identified as the major stalk cell inducer by in vitro assay, but in vivo assay revealed that DIF-1 induces only prestalkB (pstB) and prestalkO (pstO) cells and, that the major prestalkA (pstA) cells differentiated without DIF-1. In order to determine mechanism of polyketide regulated pattern formation, we examined the spatial expression patterns of prestalk and prespore markers in stlA and stlB knockout mutants. We found that MPBD regulates spore maturation at the culmination stage. We also found that the stlA and stlB double-knockout mutant lost pstA marker gene expression.
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24
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Xiong F, Tentner AR, Huang P, Gelas A, Mosaliganti KR, Souhait L, Rannou N, Swinburne IA, Obholzer ND, Cowgill PD, Schier AF, Megason SG. Specified neural progenitors sort to form sharp domains after noisy Shh signaling. Cell 2013; 153:550-61. [PMID: 23622240 DOI: 10.1016/j.cell.2013.03.023] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/22/2013] [Accepted: 03/13/2013] [Indexed: 01/09/2023]
Abstract
Sharply delineated domains of cell types arise in developing tissues under instruction of inductive signal (morphogen) gradients, which specify distinct cell fates at different signal levels. The translation of a morphogen gradient into discrete spatial domains relies on precise signal responses at stable cell positions. However, cells in developing tissues undergoing morphogenesis and proliferation often experience complex movements, which may affect their morphogen exposure, specification, and positioning. How is a clear pattern achieved with cells moving around? Using in toto imaging of the zebrafish neural tube, we analyzed specification patterns and movement trajectories of neural progenitors. We found that specified progenitors of different fates are spatially mixed following heterogeneous Sonic Hedgehog signaling responses. Cell sorting then rearranges them into sharply bordered domains. Ectopically induced motor neuron progenitors also robustly sort to correct locations. Our results reveal that cell sorting acts to correct imprecision of spatial patterning by noisy inductive signals.
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Affiliation(s)
- Fengzhu Xiong
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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Senoo H, Wang HY, Araki T, Williams JG, Fukuzawa M. An orthologue of the Myelin-gene Regulatory Transcription Factor regulates Dictyostelium prestalk differentiation. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2012; 56:325-32. [PMID: 22811266 DOI: 10.1387/ijdb.120030jw] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The prestalk region of the Dictyostelium slug is comprised of an anterior population of pstA cells and a posterior population of pstO cells. They are distinguished by their ability to utilize different parts of the promoter of the ecmA gene. We identify, by mutational analysis and DNA transformation, CA-rich sequence elements within the ecmA promoter that are essential for pstA-specific expression and sufficient to direct pstA-specific expression when multimerised. The CA-rich region was used in affinity chromatography with nuclear extracts and bound proteins were identified by mass spectrometry. The CA-rich elements purify MrfA, a protein with extensive sequence similarity to animal Myelin-gene Regulatory Factor (MRF)-like proteins. The MRF-like proteins and MrfA also display more spatially limited but significant sequence similarity with the DNA binding domain of the yeast Ndt80 sporulation-specific transcription factor. Furthermore, the ecmA CA-rich elements show sequence similarity to the core consensus Ndt80 binding site (the MSE) and point mutation of highly conserved arginine residues in MrfA, that in Ndt80 make critical contacts with the MSE, ablate binding of MrfA to its sites within the ecmA promoter. MrfA null strains are delayed in multicellular development and highly defective in pstA-specific gene expression. These results provide a first insight into the intracellular signaling pathway that directs pstA differentiation and identify a non-metazoan orthologue of a family of molecularly uncharacterised transcription factors.
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Affiliation(s)
- Hiroshi Senoo
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Japan
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Imai T, Sakano H. Axon-axon interactions in neuronal circuit assembly: lessons from olfactory map formation. Eur J Neurosci 2012; 34:1647-54. [PMID: 22103421 DOI: 10.1111/j.1460-9568.2011.07817.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
During the development of the nervous system, neurons often connect axons and dendrites over long distances, which are navigated by chemical cues. During the past few decades, studies on axon guidance have focused on chemical cues provided by the axonal target or intermediate target. However, recent studies have shed light on the roles and mechanisms underlying axon-axon interactions during neuronal circuit assembly. The roles of axon-axon interactions are best exemplified in recent studies on olfactory map formation in vertebrates. Pioneer-follower interaction is essential for the axonal pathfinding process. Pre-target axon sorting establishes the anterior-posterior map order. The temporal order of axonal projection is converted to dorsal-ventral topography with the aid of secreted molecules provided by early-arriving axons. An activity-dependent process to form a discrete map also depends on axon sorting. Thus, an emerging principle of olfactory map formation is the 'self-organisation' of axons rather than the 'lock and key' matching between axons and targets. In this review, we discuss how axon-axon interactions contribute to neuronal circuit assembly.
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Affiliation(s)
- Takeshi Imai
- Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.
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27
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Imai T. Positional information in neural map development: lessons from the olfactory system. Dev Growth Differ 2012; 54:358-65. [PMID: 22404568 DOI: 10.1111/j.1440-169x.2012.01334.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Positional information is fundamental in development. Although molecular gradients are thought to represent positional information in various systems, the molecular logic used to interpret these gradients remains controversial. In the nervous system, sensory maps are formed in the brain based on gradients of axon guidance molecules. However, it remains unclear how axons find their targets based on relative, not absolute, expression levels of axon guidance receptors. No model solely based on axon-target interactions explains this point. Recent studies in the olfactory system suggested that the neural map formation requires axon-axon interactions, which is known as axon sorting. This review discusses how axon-axon and axon-target interactions interpret molecular gradients and determine the axonal projection sites in neural map formation.
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Affiliation(s)
- Takeshi Imai
- Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology, Kobe 650-0047 PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan.
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28
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Chattwood A, Thompson CRL. Non-genetic heterogeneity and cell fate choice in Dictyostelium discoideum. Dev Growth Differ 2011; 53:558-66. [PMID: 21585359 DOI: 10.1111/j.1440-169x.2011.01270.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
From microbes to metazoans, it is now clear that fluctuations in the abundance of mRNA transcripts and protein molecules enable genetically identical cells to oscillate between several distinct states (Kaern et al. 2005). Since this cell-cell variability does not derive from physical differences in the genetic code it is termed non-genetic heterogeneity. Non-genetic heterogeneity endows cell populations with useful capabilities they could never achieve if each cell were the same as its neighbors (Raj & van Oudenaarden 2008; Eldar & Elowitz 2010). One such example is seen during multicellular development and "salt and pepper" cell type differentiation. In this review, we will first examine the importance of non-genetic heterogeneity in initiating "salt and pepper" pattern formation during Dictyostelium discoideum development. Second, we will discuss the various ways in which non-genetic heterogeneity might be generated, as well as recent advances in understanding the molecular basis of heterogeneity in this system.
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Affiliation(s)
- Alex Chattwood
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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Strassmann JE, Queller DC. Evolution of cooperation and control of cheating in a social microbe. Proc Natl Acad Sci U S A 2011; 108 Suppl 2:10855-62. [PMID: 21690338 PMCID: PMC3131822 DOI: 10.1073/pnas.1102451108] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Much of what we know about the evolution of altruism comes from animals. Here, we show that studying a microbe has yielded unique insights, particularly in understanding how social cheaters are controlled. The social stage of Dictylostelium discoideum occurs when the amoebae run out of their bacterial prey and aggregate into a multicellular, motile slug. This slug forms a fruiting body in which about a fifth of cells die to form a stalk that supports the remaining cells as they form hardy dispersal-ready spores. Because this social stage forms from aggregation, it is analogous to a social group, or a chimeric multicellular organism, and is vulnerable to internal conflict. Advances in cell labeling, microscopy, single-gene knockouts, and genomics, as well as the results of decades of study of D. discoideum as a model for development, allow us to explore the genetic basis of social contests and control of cheaters in unprecedented detail. Cheaters are limited from exploiting other clones by high relatedness, kin discrimination, pleiotropy, noble resistance, and lottery-like role assignment. The active nature of these limits is reflected in the elevated rates of change in social genes compared with nonsocial genes. Despite control of cheaters, some conflict is still expressed in chimeras, with slower movement of slugs, slightly decreased investment in stalk compared with spore cells, and differential contributions to stalk and spores. D. discoideum is rapidly becoming a model system of choice for molecular studies of social evolution.
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Affiliation(s)
- Joan E Strassmann
- Ecology and Evolutionary Biology, Rice University, Houston, TX 77005, USA.
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30
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Strassmann JE, Queller DC. How social evolution theory impacts our understanding of development in the social amoeba Dictyostelium. Dev Growth Differ 2011; 53:597-607. [DOI: 10.1111/j.1440-169x.2011.01272.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Blagg SL, Battom SE, Annesley SJ, Keller T, Parkinson K, Wu JMF, Fisher PR, Thompson CRL. Cell type-specific filamin complex regulation by a novel class of HECT ubiquitin ligase is required for normal cell motility and patterning. Development 2011; 138:1583-93. [PMID: 21389049 PMCID: PMC3062426 DOI: 10.1242/dev.063800] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2011] [Indexed: 11/20/2022]
Abstract
Differential cell motility, which plays a key role in many developmental processes, is perhaps most evident in examples of pattern formation in which the different cell types arise intermingled before sorting out into discrete tissues. This is thought to require heterogeneities in responsiveness to differentiation-inducing signals that result in the activation of cell type-specific genes and 'salt and pepper' patterning. How differential gene expression results in cell sorting is poorly defined. Here we describe a novel gene (hfnA) that provides the first mechanistic link between cell signalling, differential gene expression and cell type-specific sorting in Dictyostelium. HfnA defines a novel group of evolutionarily conserved HECT ubiquitin ligases with an N-terminal filamin domain (HFNs). HfnA expression is induced by the stalk differentiation-inducing factor DIF-1 and is restricted to a subset of prestalk cells (pstO). hfnA(-) pstO cells differentiate but their sorting out is delayed. Genetic interactions suggest that this is due to misregulation of filamin complex activity. Overexpression of filamin complex members phenocopies the hfnA(-) pstO cell sorting defect, whereas disruption of filamin complex function in a wild-type background results in pstO cells sorting more strongly. Filamin disruption in an hfnA(-) background rescues pstO cell localisation. hfnA(-) cells exhibit altered slug phototaxis phenotypes consistent with filamin complex hyperactivity. We propose that HfnA regulates filamin complex activity and cell type-specific motility through the breakdown of filamin complexes. These findings provide a novel mechanism for filamin regulation and demonstrate that filamin is a crucial mechanistic link between responses to differentiation signals and cell movement in patterning based on 'salt and pepper' differentiation and sorting out.
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Affiliation(s)
- Simone L. Blagg
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Suzanne E. Battom
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Sarah J. Annesley
- Department of Microbiology, La Trobe University, VIC 3086, Australia
| | - Thomas Keller
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Katie Parkinson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Jasmine M. F. Wu
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Paul R. Fisher
- Department of Microbiology, La Trobe University, VIC 3086, Australia
| | - Christopher R. L. Thompson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Parkinson K, Buttery NJ, Wolf JB, Thompson CRL. A simple mechanism for complex social behavior. PLoS Biol 2011; 9:e1001039. [PMID: 21468302 PMCID: PMC3066132 DOI: 10.1371/journal.pbio.1001039] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 02/18/2011] [Indexed: 11/19/2022] Open
Abstract
The evolution of cooperation is a paradox because natural selection should favor exploitative individuals that avoid paying their fair share of any costs. Such conflict between the self-interests of cooperating individuals often results in the evolution of complex, opponent-specific, social strategies and counterstrategies. However, the genetic and biological mechanisms underlying complex social strategies, and therefore the evolution of cooperative behavior, are largely unknown. To address this dearth of empirical data, we combine mathematical modeling, molecular genetic, and developmental approaches to test whether variation in the production of and response to social signals is sufficient to generate the complex partner-specific social success seen in the social amoeba Dictyostelium discoideum. Firstly, we find that the simple model of production of and response to social signals can generate the sort of apparent complex changes in social behavior seen in this system, without the need for partner recognition. Secondly, measurements of signal production and response in a mutant with a change in a single gene that leads to a shift in social behavior provide support for this model. Finally, these simple measurements of social signaling can also explain complex patterns of variation in social behavior generated by the natural genetic diversity found in isolates collected from the wild. Our studies therefore demonstrate a novel and elegantly simple underlying mechanistic basis for natural variation in complex social strategies in D. discoideum. More generally, they suggest that simple rules governing interactions between individuals can be sufficient to generate a diverse array of outcomes that appear complex and unpredictable when those rules are unknown. Despite the appearance of cooperation in nature, selection should often favor exploitative individuals who perform less of any cooperative behaviors while maintaining the benefits accrued from the cooperative behavior of others. This conflict of interest among cooperating individuals can lead to the evolution of complex social strategies that depend on the identity (e.g. genotype or strategy) of the individuals with whom you interact. The social amoeba Dictyostelium discoideum provides a compelling model for studying such “partner specific” conflict and cooperation. Upon starvation, free-living amoebae aggregate and form a fruiting body composed of dead stalk cells and hardy spores. Different genotypes will aggregate to produce chimeric fruiting bodies, resulting in potential social conflict over who will contribute to the reproductive sporehead and who will “sacrifice” themselves to produce the dead stalk. The outcomes of competitive interactions in chimera appear complex, with social success being strongly partner specific. Here we propose a simple mechanism to explain social strategies in D. discoideum, based on the production of and response to stalk-inducing factors, the social signals that determine whether cells become stalk or spore. Indeed, measurements of signal production and response can predict social behavior of different strains, thus demonstrating a novel and elegantly simple underlying mechanistic basis for natural variation in complex facultative social strategies. This suggests that simple social rules can be sufficient to generate a diverse array of behavioral outcomes that appear complex and unpredictable when those rules are unknown.
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Affiliation(s)
- Katie Parkinson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
| | - Neil J. Buttery
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
| | - Jason B. Wolf
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- * E-mail: (JBW); (CRLT)
| | - Christopher R. L. Thompson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester, United Kingdom
- * E-mail: (JBW); (CRLT)
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Abstract
The genetic circuits that regulate cellular functions are subject to stochastic fluctuations, or 'noise', in the levels of their components. Noise, far from just a nuisance, has begun to be appreciated for its essential role in key cellular activities. Noise functions in both microbial and eukaryotic cells, in multicellular development, and in evolution. It enables coordination of gene expression across large regulons, as well as probabilistic differentiation strategies that function across cell populations. At the longest timescales, noise may facilitate evolutionary transitions. Here we review examples and emerging principles that connect noise, the architecture of the gene circuits in which it is present, and the biological functions it enables. We further indicate some of the important challenges and opportunities going forward.
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Affiliation(s)
- Avigdor Eldar
- Howard Hughes Medical Institute, Caltech M/C 114-96, 1200 East California Boulevard, Pasadena, California 91125, USA
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