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Edelbroek B, Kjellin J, Jerlström-Hultqvist J, Koskiniemi S, Söderbom F. Chromosome-level genome assembly and annotation of the social amoeba Dictyostelium firmibasis. Sci Data 2024; 11:678. [PMID: 38909042 PMCID: PMC11193728 DOI: 10.1038/s41597-024-03513-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 06/12/2024] [Indexed: 06/24/2024] Open
Abstract
Dicytostelium firmibasis is a member of Dictyostelia, a group of social amoebae that upon starvation display aggregative multicellularity where the amoebae transition from uni- to multicellular life. The D. firmibasis genome assembly that is currently available is of limited use due to its low contiguity, large number of undetermined bases, and lack of annotations. Here we used Nanopore long read sequencing, complemented with Illumina sequencing, and developmental transcriptomics as well as small RNA-sequencing, to present a new, fully annotated, chromosome-level D. firmibasis genome assembly. The new assembly contains no undetermined bases, and consists mainly of six large contigs representing the chromosomes, as well as a complete mitochondrial genome. This new genome assembly will be a valuable tool, allowing comprehensive comparison to Dictyostelium discoideum, the dictyostelid genetically tractable model. Further, the new genome will be important for studies of evolutionary processes governing the transition from unicellular to multicellular organisms and will aid in the sequencing and annotation of other dictyostelids genomes, many of which are currently of poor quality.
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Affiliation(s)
- Bart Edelbroek
- Department of Cell and Molecular Biology, BMC, Uppsala University, SE-751 24, Uppsala, Sweden.
| | - Jonas Kjellin
- Department of Cell and Molecular Biology, BMC, Uppsala University, SE-751 24, Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Department of Cell and Molecular Biology, BMC, Uppsala University, SE-751 24, Uppsala, Sweden
| | - Sanna Koskiniemi
- Department of Cell and Molecular Biology, BMC, Uppsala University, SE-751 24, Uppsala, Sweden
| | - Fredrik Söderbom
- Department of Cell and Molecular Biology, BMC, Uppsala University, SE-751 24, Uppsala, Sweden.
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2
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Proverbio D. Chemotaxis in heterogeneous environments: A multi-agent model of decentralized gathering past obstacles. J Theor Biol 2024; 586:111820. [PMID: 38604596 DOI: 10.1016/j.jtbi.2024.111820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/13/2024]
Abstract
Chemotaxis, cell migration in response to chemical gradients, is known to promote self-organization of microbiological populations. However, the modeling of chemotaxis in heterogeneous environments is still limited. This study analyzes a decentralized gathering process in environments with physical as well as chemical barriers, using a multi-agent model for Disctyostelium discoideum colonies. Employing a topology-independent metric to quantify the system evolution, we study dynamical features emerging from complex social interactions. The results show that obstacles may hamper the gathering process by altering the flux of chemical signals among amoebas, acting as local topological perturbations. We also find that a minimal set of agent's rules for robust gathering does not require explicit mechanisms for obstacle sensing and avoidance; moreover, random cell movements concur in preventing multiple stable clusters and improve the gathering efficacy. Hence, we speculate that chemotactic cells can avoid obstacles without needing specialized mechanisms: tradeoffs of social interactions and individual fluctuations are sufficient to guarantee the aggregation of the whole colony past numerous obstacles.
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Affiliation(s)
- Daniele Proverbio
- Department of Industrial Engineering, University of Trento, 9 via Sommarive, 38123 Trento, Italy.
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3
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Erisis S, Hörning M. Self-organization of PIP3 waves is controlled by the topology and curvature of cell membranes. Biophys J 2024; 123:1058-1068. [PMID: 38515298 PMCID: PMC11079865 DOI: 10.1016/j.bpj.2024.03.022] [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: 01/25/2024] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024] Open
Abstract
Phosphatidylinositol (3,4,5)-trisphosphate (PIP3) is a signaling lipid on the plasma membrane that plays a fundamental role in cell signaling with a strong impact on cell physiology and diseases. It is responsible for the protruding edge formation, cell polarization, macropinocytosis, and other membrane remodeling dynamics in cells. It has been shown that the membrane confinement and curvature affects the wave formation of PIP3 and F-actin. But, even in the absence of F-actin, a complex self-organization of the spatiotemporal PIP3 waves is observed. In recent findings, we have shown that these waves can be guided and pinned on strongly bended Dictyostelium membranes caused by molecular crowding and curvature-limited diffusion. Based on these experimental findings, we investigate the spatiotemporal PIP3 wave dynamics on realistic three-dimensional cell-like membranes to explore the effect of curvature-limited diffusion, as observed experimentally. We use an established stochastic reaction-diffusion model with enzymatic Michaelis-Menten-type reactions that mimics the dynamics of Dictyostelium cells. As these cells mimic the three-dimensional shape and size observed experimentally, we found that the PIP3 wave directionality can be explained by a Hopf-like and a reverse periodic-doubling bifurcation for uniform diffusion and curvature-limited diffusion properties. Finally, we compare the results with recent experimental findings and discuss the discrepancy between the biological and numerical results.
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Affiliation(s)
- Sema Erisis
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Marcel Hörning
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany.
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4
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Edelbroek B, Kjellin J, Biryukova I, Liao Z, Lundberg T, Noegel A, Eichinger L, Friedländer M, Söderbom F. Evolution of microRNAs in Amoebozoa and implications for the origin of multicellularity. Nucleic Acids Res 2024; 52:3121-3136. [PMID: 38375870 PMCID: PMC11014262 DOI: 10.1093/nar/gkae109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/21/2024] Open
Abstract
MicroRNAs (miRNAs) are important and ubiquitous regulators of gene expression in both plants and animals. They are thought to have evolved convergently in these lineages and hypothesized to have played a role in the evolution of multicellularity. In line with this hypothesis, miRNAs have so far only been described in few unicellular eukaryotes. Here, we investigate the presence and evolution of miRNAs in Amoebozoa, focusing on species belonging to Acanthamoeba, Physarum and dictyostelid taxonomic groups, representing a range of unicellular and multicellular lifestyles. miRNAs that adhere to both the stringent plant and animal miRNA criteria were identified in all examined amoebae, expanding the total number of protists harbouring miRNAs from 7 to 15. We found conserved miRNAs between closely related species, but the majority of species feature only unique miRNAs. This shows rapid gain and/or loss of miRNAs in Amoebozoa, further illustrated by a detailed comparison between two evolutionary closely related dictyostelids. Additionally, loss of miRNAs in the Dictyostelium discoideum drnB mutant did not seem to affect multicellular development and, hence, demonstrates that the presence of miRNAs does not appear to be a strict requirement for the transition from uni- to multicellular life.
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Affiliation(s)
- Bart Edelbroek
- Department of Cell and Molecular Biology, Uppsala Biomedical Centre, Uppsala University, 75124 Uppsala, Sweden
| | - Jonas Kjellin
- Department of Cell and Molecular Biology, Uppsala Biomedical Centre, Uppsala University, 75124 Uppsala, Sweden
| | - Inna Biryukova
- Science for Life Laboratory, The Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Zhen Liao
- Department of Cell and Molecular Biology, Uppsala Biomedical Centre, Uppsala University, 75124 Uppsala, Sweden
| | - Torgny Lundberg
- Department of Cell and Molecular Biology, Uppsala Biomedical Centre, Uppsala University, 75124 Uppsala, Sweden
| | - Angelika A Noegel
- Centre for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Ludwig Eichinger
- Centre for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Marc R Friedländer
- Science for Life Laboratory, The Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Fredrik Söderbom
- Department of Cell and Molecular Biology, Uppsala Biomedical Centre, Uppsala University, 75124 Uppsala, Sweden
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5
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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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Kuhn J, Lin Y, Devreotes PN. Using Live-Cell Imaging and Synthetic Biology to Probe Directed Migration in Dictyostelium. Front Cell Dev Biol 2021; 9:740205. [PMID: 34676215 PMCID: PMC8523838 DOI: 10.3389/fcell.2021.740205] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/08/2021] [Indexed: 12/30/2022] Open
Abstract
For decades, the social amoeba Dictyostelium discoideum has been an invaluable tool for dissecting the biology of eukaryotic cells. Its short growth cycle and genetic tractability make it ideal for a variety of biochemical, cell biological, and biophysical assays. Dictyostelium have been widely used as a model of eukaryotic cell motility because the signaling and mechanical networks which they use to steer and produce forward motion are highly conserved. Because these migration networks consist of hundreds of interconnected proteins, perturbing individual molecules can have subtle effects or alter cell morphology and signaling in major unpredictable ways. Therefore, to fully understand this network, we must be able to quantitatively assess the consequences of abrupt modifications. This ability will allow us better control cell migration, which is critical for development and disease, in vivo. Here, we review recent advances in imaging, synthetic biology, and computational analysis which enable researchers to tune the activity of individual molecules in single living cells and precisely measure the effects on cellular motility and signaling. We also provide practical advice and resources to assist in applying these approaches in Dictyostelium.
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7
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Baines RP, Wolton K, Thompson CRL. Dictyostelium discoideum: an alternative non-animal model for developmental toxicity testing. Toxicol Sci 2021; 183:302-318. [PMID: 34387693 PMCID: PMC8538044 DOI: 10.1093/toxsci/kfab097] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A critical aspect of toxicity evaluation is developmental and reproductive toxicity (DART) testing. Traditionally, DART testing has been conducted in vivo in mammalian model systems. New legislation aimed at reducing animal use and the prohibitive costs associated with DART testing, together with a need to understand the genetic pathways underlying developmental toxicity means there is a growing demand for alternative model systems for toxicity evaluation. Here we explore the potential of the eukaryotic social amoeba Dictyostelium discoideum, which is already widely used as a simple model system for cell and developmental biology, as a potential nonanimal model for DART testing. We developed assays for high-throughput screening of toxicity during D. discoideum growth and development. This allowed the toxicity of a broad range of test compounds to be characterized, which revealed that D. discoideum can broadly predict mammalian toxicity. In addition, we show that this system can be used to perform functional genomic screens to compare the molecular modes of action of different compounds. For example, genome-wide screens for mutations that affect lithium and valproic acid toxicity allowed common and unique biological targets and molecular processes mediating their toxicity to be identified. These studies illustrate that D. discoideum could represent a predictive nonanimal model for DART testing due to its amenability to high-throughput approaches and molecular genetic tractability.
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Affiliation(s)
- Robert P Baines
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
| | - Kathryn Wolton
- Syngenta, Jealott's Hill International Research Centre, RG42 6EY Bracknell, Berkshire
| | - Christopher R L Thompson
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT, UK
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8
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Nalamalapu RR, Yue M, Stone AR, Murphy S, Saha MS. The tweety Gene Family: From Embryo to Disease. Front Mol Neurosci 2021; 14:672511. [PMID: 34262434 PMCID: PMC8273234 DOI: 10.3389/fnmol.2021.672511] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/18/2021] [Indexed: 12/31/2022] Open
Abstract
The tweety genes encode gated chloride channels that are found in animals, plants, and even simple eukaryotes, signifying their deep evolutionary origin. In vertebrates, the tweety gene family is highly conserved and consists of three members—ttyh1, ttyh2, and ttyh3—that are important for the regulation of cell volume. While research has elucidated potential physiological functions of ttyh1 in neural stem cell maintenance, proliferation, and filopodia formation during neural development, the roles of ttyh2 and ttyh3 are less characterized, though their expression patterns during embryonic and fetal development suggest potential roles in the development of a wide range of tissues including a role in the immune system in response to pathogen-associated molecules. Additionally, members of the tweety gene family have been implicated in various pathologies including cancers, particularly pediatric brain tumors, and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. Here, we review the current state of research using information from published articles and open-source databases on the tweety gene family with regard to its structure, evolution, expression during development and adulthood, biochemical and cellular functions, and role in human disease. We also identify promising areas for further research to advance our understanding of this important, yet still understudied, family of genes.
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Affiliation(s)
- Rithvik R Nalamalapu
- Department of Biology, College of William and Mary, Williamsburg, VA, United States
| | - Michelle Yue
- Department of Biology, College of William and Mary, Williamsburg, VA, United States
| | - Aaron R Stone
- Department of Biology, College of William and Mary, Williamsburg, VA, United States
| | - Samantha Murphy
- Department of Biology, College of William and Mary, Williamsburg, VA, United States
| | - Margaret S Saha
- Department of Biology, College of William and Mary, Williamsburg, VA, United States
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9
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Assessing the robustness of decentralized gathering: a multi-agent approach on micro-biological systems. SWARM INTELLIGENCE 2020. [DOI: 10.1007/s11721-020-00186-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Olmos J, Pignataro MF, Benítez dos Santos AB, Bringas M, Klinke S, Kamenetzky L, Velazquez F, Santos J. A Highly Conserved Iron-Sulfur Cluster Assembly Machinery between Humans and Amoeba Dictyostelium discoideum: The Characterization of Frataxin. Int J Mol Sci 2020; 21:E6821. [PMID: 32957566 PMCID: PMC7554988 DOI: 10.3390/ijms21186821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Several biological activities depend on iron-sulfur clusters ([Fe-S]). Even though they are well-known in several organisms their function and metabolic pathway were poorly understood in the majority of the organisms. We propose to use the amoeba Dictyostelium discoideum, as a biological model to study the biosynthesis of [Fe-S] at the molecular, cellular and organism levels. First, we have explored the D. discoideum genome looking for genes corresponding to the subunits that constitute the molecular machinery for Fe-S cluster assembly and, based on the structure of the mammalian supercomplex and amino acid conservation profiles, we inferred the full functionality of the amoeba machinery. After that, we expressed the recombinant mature form of D. discoideum frataxin protein (DdFXN), the kinetic activator of this pathway. We characterized the protein and its conformational stability. DdFXN is monomeric and compact. The analysis of the secondary structure content, calculated using the far-UV CD spectra, was compatible with the data expected for the FXN fold, and near-UV CD spectra were compatible with the data corresponding to a folded protein. In addition, Tryptophan fluorescence indicated that the emission occurs from an apolar environment. However, the conformation of DdFXN is significantly less stable than that of the human FXN, (4.0 vs. 9.0 kcal mol-1, respectively). Based on a sequence analysis and structural models of DdFXN, we investigated key residues involved in the interaction of DdFXN with the supercomplex and the effect of point mutations on the energetics of the DdFXN tertiary structure. More than 10 residues involved in Friedreich's Ataxia are conserved between the human and DdFXN forms, and a good correlation between mutational effect on the energetics of both proteins were found, suggesting the existence of similar sequence/function/stability relationships. Finally, we integrated this information in an evolutionary context which highlights particular variation patterns between amoeba and humans that may reflect a functional importance of specific protein positions. Moreover, the complete pathway obtained forms a piece of evidence in favor of the hypothesis of a shared and highly conserved [Fe-S] assembly machinery between Human and D. discoideum.
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Affiliation(s)
- Justo Olmos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - María Florencia Pignataro
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Ana Belén Benítez dos Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Mauro Bringas
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE CONICET), Buenos Aires C1428EGA, Argentina;
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, and Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina;
| | - Laura Kamenetzky
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- IMPaM, CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
| | - Francisco Velazquez
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN)—(UBA/CONICET), Buenos Aires C1428EGA, Argentina
| | - Javier Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Rivadavia 1917, Buenos Aires C1033AAJ, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina
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11
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Low Base-Substitution Mutation Rate but High Rate of Slippage Mutations in the Sequence Repeat-Rich Genome of Dictyostelium discoideum. G3-GENES GENOMES GENETICS 2020; 10:3445-3452. [PMID: 32732307 PMCID: PMC7466956 DOI: 10.1534/g3.120.401578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We describe the rate and spectrum of spontaneous mutations for the social amoeba Dictyostelium discoideum, a key model organism in molecular, cellular, evolutionary and developmental biology. Whole-genome sequencing of 37 mutation accumulation lines of D. discoideum after an average of 1,500 cell divisions yields a base-substitution mutation rate of 2.47 × 10−11 per site per generation, substantially lower than that of most eukaryotic and prokaryotic organisms, and of the same order of magnitude as in the ciliates Paramecium tetraurelia and Tetrahymena thermophila. Known for its high genomic AT content and abundance of simple sequence repeats, we observe that base-substitution mutations in D. discoideum are highly A/T biased. This bias likely contributes both to the high genomic AT content and to the formation of simple sequence repeats in the AT-rich genome of Dictyostelium discoideum. In contrast to the situation in other surveyed unicellular eukaryotes, indel rates far exceed the base-substitution mutation rate in this organism with a high proportion of 3n indels, particularly in regions without simple sequence repeats. Like ciliates, D. discoideum has a large effective population size, reducing the power of random genetic drift, magnifying the effect of selection on replication fidelity, in principle allowing D. discoideum to evolve an extremely low base-substitution mutation rate.
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12
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Hayakawa M, Hiraiwa T, Wada Y, Kuwayama H, Shibata T. Polar pattern formation induced by contact following locomotion in a multicellular system. eLife 2020; 9:53609. [PMID: 32352381 PMCID: PMC7213982 DOI: 10.7554/elife.53609] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/15/2020] [Indexed: 12/23/2022] Open
Abstract
Biophysical mechanisms underlying collective cell migration of eukaryotic cells have been studied extensively in recent years. One mechanism that induces cells to correlate their motions is contact inhibition of locomotion, by which cells migrating away from the contact site. Here, we report that tail-following behavior at the contact site, termed contact following locomotion (CFL), can induce a non-trivial collective behavior in migrating cells. We show the emergence of a traveling band showing polar order in a mutant Dictyostelium cell that lacks chemotactic activity. We find that CFL is the cell-cell interaction underlying this phenomenon, enabling a theoretical description of how this traveling band forms. We further show that the polar order phase consists of subpopulations that exhibit characteristic transversal motions with respect to the direction of band propagation. These findings describe a novel mechanism of collective cell migration involving cell-cell interactions capable of inducing traveling band with polar order.
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Affiliation(s)
- Masayuki Hayakawa
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Tetsuya Hiraiwa
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore.,Universal Biology Institute, University of Tokyo, Tokyo, Japan
| | - Yuko Wada
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Hidekazu Kuwayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai, Ibaraki, Japan
| | - Tatsuo Shibata
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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13
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Rodriguez-Centeno J, Manguán-García C, Perona R, Sastre L. Structure of Dictyostelium discoideum telomeres. Analysis of possible replication mechanisms. PLoS One 2019; 14:e0222909. [PMID: 31550289 PMCID: PMC6759168 DOI: 10.1371/journal.pone.0222909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 09/10/2019] [Indexed: 12/14/2022] Open
Abstract
Telomeres are nucleo-protein structures that protect the ends of eukaryotic chromosomes. They are not completely synthesized during DNA replication and are elongated by specific mechanisms. The structure of the telomeres and the elongation mechanism have not been determined in Dictyostelium discoideum. This organism presents extrachromosomal palindromic elements containing two copies of the rDNA, also present at the end of the chromosomes. In this article the structure of the terminal region of the rDNA is shown to consist of repetitions of the A(G)n sequence where the number of Gs is variable. These repeats extend as a 3’ single stranded region. The G-rich region is preceded by four tandem repetitions of two different DNA motifs. D. discoideum telomere reverse transcriptase homologous protein (TERTHP) presented RNase-sensitive enzymatic activity and was required to maintain telomere structure since terthp-mutant strains presented reorganizations of the DNA terminal regions. These modifications were different in several terthp-mutants and changed with their prolonged culture and subcloning. However, the terthp gene is not essential for D. discoideum proliferation. Telomeres could be maintained in terthp-mutant strains by homologous recombination mechanisms such as ALT (Alternative Lengthening of Telomeres) or HAATI (heterochromatin amplification-mediated and telomerase-independent). In agreement with this hypothesis, the expression of mRNAs coding for several proteins involved in homologous recombination was induced in terthp-mutant strains. Extrachromosomal rDNA could serve as substrate in these DNA homologous recombination reactions.
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Affiliation(s)
- Javier Rodriguez-Centeno
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
| | - Cristina Manguán-García
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Rosario Perona
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- * E-mail:
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14
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Witzel P, Götz M, Lanoiselée Y, Franosch T, Grebenkov DS, Heinrich D. Heterogeneities Shape Passive Intracellular Transport. Biophys J 2019; 117:203-213. [PMID: 31278001 PMCID: PMC6700759 DOI: 10.1016/j.bpj.2019.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/22/2019] [Accepted: 06/11/2019] [Indexed: 01/06/2023] Open
Abstract
A living cell's interior is one of the most complex and intrinsically dynamic systems, providing an elaborate interplay between cytosolic crowding and ATP-driven motion that controls cellular functionality. Here, we investigated two distinct fundamental features of the merely passive, non-biomotor-shuttled material transport within the cytoplasm of Dictyostelium discoideum cells: the anomalous non-linear scaling of the mean-squared displacement of a 150-nm-diameter particle and non-Gaussian distribution of increments. Relying on single-particle tracking data of 320,000 data points, we performed a systematic analysis of four possible origins for non-Gaussian transport: 1) sample-based variability, 2) rarely occurring strong motion events, 3) ergodicity breaking/aging, and 4) spatiotemporal heterogeneities of the intracellular medium. After excluding the first three reasons, we investigated the remaining hypothesis of a heterogeneous cytoplasm as cause for non-Gaussian transport. A, to our knowledge, novel fit model with randomly distributed diffusivities implementing medium heterogeneities suits the experimental data. Strikingly, the non-Gaussian feature is independent of the cytoskeleton condition and lag time. This reveals that efficiency and consistency of passive intracellular transport and the related anomalous scaling of the mean-squared displacement are regulated by cytoskeleton components, whereas cytoplasmic heterogeneities are responsible for the generic, non-Gaussian distribution of increments.
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Affiliation(s)
- Patrick Witzel
- Faculty for Chemistry and Pharmacy, Julius-Maximilians-Universität Würzburg, Würzburg, Germany; Fraunhofer Institute for Silicate Research ISC, Würzburg, Germany
| | - Maria Götz
- Faculty for Chemistry and Pharmacy, Julius-Maximilians-Universität Würzburg, Würzburg, Germany; Fraunhofer Institute for Silicate Research ISC, Würzburg, Germany
| | - Yann Lanoiselée
- Laboratoire de Physique de la Matière Condensée, CNRS-Ecole Polytechnique, Palaiseau, France
| | - Thomas Franosch
- Institut für Theoretische Physik, Universität Innsbruck, Innsbruck, Austria
| | - Denis S Grebenkov
- Laboratoire de Physique de la Matière Condensée, CNRS-Ecole Polytechnique, Palaiseau, France
| | - Doris Heinrich
- Fraunhofer Institute for Silicate Research ISC, Würzburg, Germany; Leiden Institute of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, the Netherlands.
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15
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A telomerase with novel non-canonical roles: TERT controls cellular aggregation and tissue size in Dictyostelium. PLoS Genet 2019; 15:e1008188. [PMID: 31237867 PMCID: PMC6592521 DOI: 10.1371/journal.pgen.1008188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/10/2019] [Indexed: 11/19/2022] Open
Abstract
Telomerase, particularly its main subunit, the reverse transcriptase, TERT, prevents DNA erosion during eukaryotic chromosomal replication, but also has poorly understood non-canonical functions. Here, in the model social amoeba Dictyostelium discoideum, we show that the protein encoded by tert has telomerase-like motifs, and regulates, non-canonically, important developmental processes. Expression levels of wild-type (WT) tert were biphasic, peaking at 8 and 12 h post-starvation, aligning with developmental events, such as the initiation of streaming (~7 h) and mound formation (~10 h). In tert KO mutants, however, aggregation was delayed until 16 h. Large, irregular streams formed, then broke up, forming small mounds. The mound-size defect was not induced when a KO mutant of countin (a master size-regulating gene) was treated with TERT inhibitors, but anti-countin antibodies did rescue size in the tert KO. Although, conditioned medium (CM) from countin mutants failed to rescue size in the tert KO, tert KO CM rescued the countin KO phenotype. These and additional observations indicate that TERT acts upstream of smlA/countin: (i) the observed expression levels of smlA and countin, being respectively lower and higher (than WT) in the tert KO; (ii) the levels of known size-regulation intermediates, glucose (low) and adenosine (high), in the tert mutant, and the size defect's rescue by supplemented glucose or the adenosine-antagonist, caffeine; (iii) the induction of the size defect in the WT by tert KO CM and TERT inhibitors. The tert KO's other defects (delayed aggregation, irregular streaming) were associated with changes to cAMP-regulated processes (e.g. chemotaxis, cAMP pulsing) and their regulatory factors (e.g. cAMP; acaA, carA expression). Overexpression of WT tert in the tert KO rescued these defects (and size), and restored a single cAMP signaling centre. Our results indicate that TERT acts in novel, non-canonical and upstream ways, regulating key developmental events in Dictyostelium.
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16
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Proteins of the Nucleolus of Dictyostelium discoideum: Nucleolar Compartmentalization, Targeting Sequences, Protein Translocations and Binding Partners. Cells 2019; 8:cells8020167. [PMID: 30781559 PMCID: PMC6406644 DOI: 10.3390/cells8020167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/31/2022] Open
Abstract
The nucleoli of Dictyostelium discoideum have a comparatively unique, non-canonical, localization adjacent to the inner nuclear membrane. The verified nucleolar proteins of this eukaryotic microbe are detailed while other potential proteins are introduced. Heat shock protein 32 (Hsp32), eukaryotic translation initiation factor 6 (eIF6), and tumour necrosis factor receptor-associated protein 1 (TRAP1) are essential for cell survival. NumA1, a breast cancer type 1 susceptibility protein-C Terminus domain-containing protein linked to cell cycle, functions in the regulation of nuclear number. The cell cycle checkpoint kinase 2 homologue forkhead-associated kinase A (FhkA) and BRG1-associated factor 60a homologue Snf12 are also discussed. While nucleoli appear homogeneous ultrastructurally, evidence for nucleolar subcompartments exists. Nucleolar localization sequences (NoLS) have been defined that target proteins to either the general nucleolar area or to a specific intranucleolar domain. Protein translocations during mitosis are protein-specific and support the multiple functions of the Dictyostelium nucleolus. To enrich the picture, binding partners of NumA1, the most well-characterized nucleolar protein, are examined: nucleolar Ca2+-binding protein 4a (CBP4a), nuclear puromycin-sensitive aminopeptidase A (PsaA) and Snf12. The role of Dictyostelium as a model for understanding the contribution of nucleolar proteins to various diseases and cellular stress is discussed throughout the review.
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17
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Kida Y, Pan K, Kuwayama H. Some chemotactic mutants can be progress through development in chimeric populations. Differentiation 2019; 105:71-79. [PMID: 30797173 DOI: 10.1016/j.diff.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/31/2019] [Accepted: 02/08/2019] [Indexed: 01/23/2023]
Abstract
Cell migration in response to morphogen gradients affects morphogenesis. Chemotaxis towards adenosine 3', 5'-monophosphate (cAMP) is essential for the early stage of morphogenesis in the slime mold Dictyostelium discoideum. Here, we show that D. discoideum completes morphogenesis without cAMP-chemotaxis-dependent cell migration. The extracellular cAMP gradient is believed to cause cells to form a slug-shaped multicellular structure and fruiting body. The cAMP receptor, cAR1, was not expressed at the cell surface during these stages, correlating with reduced chemotactic activity. Gβ-null cells expressing temperature sensitive Gβ are unable to generate extracellular cAMP (Jin et al., 1998) and thus unable to aggregate and exhibit proper morphogenesis under restrictive temperature. However, when mixed with wild type cells ts-Gβ expressing gβ-null cells normally aggregated and exhibited normal morphogenesis under restrictive temperature. Furthermore, cells migrated after aggregation in a mixture containing wild-type cells. KI-5 cells, which do not show aggregation or morphogenesis, spontaneously migrated to a transplanted wild-type tip and underwent normal morphogenesis and cell differentiation; this was not observed in cells lacking tgrB1and tgrC1 cells adhesion molecules. Thus, cAMP gradient-dependent cell migration may not be required for multicellular pattern formation in late Dictyostelium development.
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Affiliation(s)
- Yuya Kida
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai, 1-1-1, Tsukuba, Ibaraki 305-8572, Japan
| | - Kai Pan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai, 1-1-1, Tsukuba, Ibaraki 305-8572, Japan
| | - Hidekazu Kuwayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai, 1-1-1, Tsukuba, Ibaraki 305-8572, Japan.
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18
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Recent Advances in CRISPR/Cas9-Mediated Genome Editing in Dictyostelium. Cells 2019; 8:cells8010046. [PMID: 30642074 PMCID: PMC6356401 DOI: 10.3390/cells8010046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 12/18/2022] Open
Abstract
In the last 30 years, knockout of target genes via homologous recombination has been widely performed to clarify the physiological functions of proteins in Dictyostelium. As of late, CRISPR/Cas9-mediated genome editing has become a versatile tool in various organisms, including Dictyostelium, enabling rapid high-fidelity modification of endogenous genes. Here we reviewed recent progress in genome editing in Dictyostelium and summarised useful CRISPR vectors that express sgRNA and Cas9, including several microorganisms. Using these vectors, precise genome modifications can be achieved within 2–3 weeks, beginning with the design of the target sequence. Finally, we discussed future perspectives on the use of CRISPR/Cas9-mediated genome editing in Dictyostelium.
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19
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Agent-based models for first- and second-order emergent collective behaviours of social amoeba Dictyostelium discoideum aggregation and migration phases. ARTIFICIAL LIFE AND ROBOTICS 2018. [DOI: 10.1007/s10015-018-0477-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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20
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Unfolding the Endoplasmic Reticulum of a Social Amoeba: Dictyostelium discoideum as a New Model for the Study of Endoplasmic Reticulum Stress. Cells 2018; 7:cells7060056. [PMID: 29890774 PMCID: PMC6025073 DOI: 10.3390/cells7060056] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/28/2018] [Accepted: 06/05/2018] [Indexed: 01/19/2023] Open
Abstract
The endoplasmic reticulum (ER) is a membranous network with an intricate dynamic architecture necessary for various essential cellular processes. Nearly one third of the proteins trafficking through the secretory pathway are folded and matured in the ER. Additionally, it acts as calcium storage, and it is a main source for lipid biosynthesis. The ER is highly connected with other organelles through regions of membrane apposition that allow organelle remodeling, as well as lipid and calcium traffic. Cells are under constant changes due to metabolic requirements and environmental conditions that challenge the ER network’s maintenance. The unfolded protein response (UPR) is a signaling pathway that restores homeostasis of this intracellular compartment upon ER stress conditions by reducing the load of proteins, and by increasing the processes of protein folding and degradation. Significant progress on the study of the mechanisms that restore ER homeostasis was achieved using model organisms such as yeast, Arabidopsis, and mammalian cells. In this review, we address the current knowledge on ER architecture and ER stress response in Dictyostelium discoideum. This social amoeba alternates between unicellular and multicellular phases and is recognized as a valuable biomedical model organism and an alternative to yeast, particularly for the presence of traits conserved in animal cells that were lost in fungi.
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21
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Nicolussi A, Dunn JD, Mlynek G, Bellei M, Zamocky M, Battistuzzi G, Djinović-Carugo K, Furtmüller PG, Soldati T, Obinger C. Secreted heme peroxidase from Dictyostelium discoideum: Insights into catalysis, structure, and biological role. J Biol Chem 2017; 293:1330-1345. [PMID: 29242189 PMCID: PMC5787809 DOI: 10.1074/jbc.ra117.000463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/01/2017] [Indexed: 12/16/2022] Open
Abstract
Oxidation of halides and thiocyanate by heme peroxidases to antimicrobial oxidants is an important cornerstone in the innate immune system of mammals. Interestingly, phylogenetic and physiological studies suggest that homologous peroxidases are already present in mycetozoan eukaryotes such as Dictyostelium discoideum This social amoeba kills bacteria via phagocytosis for nutrient acquisition at its single-cell stage and for antibacterial defense at its multicellular stages. Here, we demonstrate that peroxidase A from D. discoideum (DdPoxA) is a stable, monomeric, glycosylated, and secreted heme peroxidase with homology to mammalian peroxidases. The first crystal structure (2.5 Å resolution) of a mycetozoan peroxidase of this superfamily shows the presence of a post-translationally-modified heme with one single covalent ester bond between the 1-methyl heme substituent and Glu-236. The metalloprotein follows the halogenation cycle, whereby compound I oxidizes iodide and thiocyanate at high rates (>108 m-1 s-1) and bromide at very low rates. It is demonstrated that DdPoxA is up-regulated and likely secreted at late multicellular development stages of D. discoideum when migrating slugs differentiate into fruiting bodies that contain persistent spores on top of a cellular stalk. Expression of DdPoxA is shown to restrict bacterial contamination of fruiting bodies. Structure and function of DdPoxA are compared with evolutionary-related mammalian peroxidases in the context of non-specific immune defense.
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Affiliation(s)
- Andrea Nicolussi
- From the Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Joe Dan Dunn
- the Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Genève, Switzerland
| | - Georg Mlynek
- the Department for Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | | | - Marcel Zamocky
- From the Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, 1190 Vienna, Austria.,the Institute of Molecular Biology, Slovak Academy of Sciences, 84551 Bratislava, Slovakia, and
| | - Gianantonio Battistuzzi
- Chemistry and Geology, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Kristina Djinović-Carugo
- the Department for Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria.,the Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Paul G Furtmüller
- From the Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Thierry Soldati
- the Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Genève, Switzerland
| | - Christian Obinger
- From the Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences, 1190 Vienna, Austria,
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22
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Plattner H. Evolutionary Cell Biology of Proteins from Protists to Humans and Plants. J Eukaryot Microbiol 2017; 65:255-289. [PMID: 28719054 DOI: 10.1111/jeu.12449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/04/2017] [Accepted: 07/07/2017] [Indexed: 01/10/2023]
Abstract
During evolution, the cell as a fine-tuned machine had to undergo permanent adjustments to match changes in its environment, while "closed for repair work" was not possible. Evolution from protists (protozoa and unicellular algae) to multicellular organisms may have occurred in basically two lineages, Unikonta and Bikonta, culminating in mammals and angiosperms (flowering plants), respectively. Unicellular models for unikont evolution are myxamoebae (Dictyostelium) and increasingly also choanoflagellates, whereas for bikonts, ciliates are preferred models. Information accumulating from combined molecular database search and experimental verification allows new insights into evolutionary diversification and maintenance of genes/proteins from protozoa on, eventually with orthologs in bacteria. However, proteins have rarely been followed up systematically for maintenance or change of function or intracellular localization, acquirement of new domains, partial deletion (e.g. of subunits), and refunctionalization, etc. These aspects are discussed in this review, envisaging "evolutionary cell biology." Protozoan heritage is found for most important cellular structures and functions up to humans and flowering plants. Examples discussed include refunctionalization of voltage-dependent Ca2+ channels in cilia and replacement by other types during evolution. Altogether components serving Ca2+ signaling are very flexible throughout evolution, calmodulin being a most conservative example, in contrast to calcineurin whose catalytic subunit is lost in plants, whereas both subunits are maintained up to mammals for complex functions (immune defense and learning). Domain structure of R-type SNAREs differs in mono- and bikonta, as do Ca2+ -dependent protein kinases. Unprecedented selective expansion of the subunit a which connects multimeric base piece and head parts (V0, V1) of H+ -ATPase/pump may well reflect the intriguing vesicle trafficking system in ciliates, specifically in Paramecium. One of the most flexible proteins is centrin when its intracellular localization and function throughout evolution is traced. There are many more examples documenting evolutionary flexibility of translation products depending on requirements and potential for implantation within the actual cellular context at different levels of evolution. From estimates of gene and protein numbers per organism, it appears that much of the basic inventory of protozoan precursors could be transmitted to highest eukaryotic levels, with some losses and also with important additional "inventions."
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, P. O. Box M625, Konstanz, 78457, Germany
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23
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Szabo M, Svensson Akusjärvi S, Saxena A, Liu J, Chandrasekar G, Kitambi SS. Cell and small animal models for phenotypic drug discovery. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:1957-1967. [PMID: 28721015 PMCID: PMC5500539 DOI: 10.2147/dddt.s129447] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The phenotype-based drug discovery (PDD) approach is re-emerging as an alternative platform for drug discovery. This review provides an overview of the various model systems and technical advances in imaging and image analyses that strengthen the PDD platform. In PDD screens, compounds of therapeutic value are identified based on the phenotypic perturbations produced irrespective of target(s) or mechanism of action. In this article, examples of phenotypic changes that can be detected and quantified with relative ease in a cell-based setup are discussed. In addition, a higher order of PDD screening setup using small animal models is also explored. As PDD screens integrate physiology and multiple signaling mechanisms during the screening process, the identified hits have higher biomedical applicability. Taken together, this review highlights the advantages gained by adopting a PDD approach in drug discovery. Such a PDD platform can complement target-based systems that are currently in practice to accelerate drug discovery.
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Affiliation(s)
- Mihaly Szabo
- Department of Microbiology Tumor, and Cell Biology
| | | | - Ankur Saxena
- Department of Microbiology Tumor, and Cell Biology
| | - Jianping Liu
- Department of Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
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24
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Stajdohar M, Rosengarten RD, Kokosar J, Jeran L, Blenkus D, Shaulsky G, Zupan B. dictyExpress: a web-based platform for sequence data management and analytics in Dictyostelium and beyond. BMC Bioinformatics 2017; 18:291. [PMID: 28578698 PMCID: PMC5457571 DOI: 10.1186/s12859-017-1706-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 05/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dictyostelium discoideum, a soil-dwelling social amoeba, is a model for the study of numerous biological processes. Research in the field has benefited mightily from the adoption of next-generation sequencing for genomics and transcriptomics. Dictyostelium biologists now face the widespread challenges of analyzing and exploring high dimensional data sets to generate hypotheses and discovering novel insights. RESULTS We present dictyExpress (2.0), a web application designed for exploratory analysis of gene expression data, as well as data from related experiments such as Chromatin Immunoprecipitation sequencing (ChIP-Seq). The application features visualization modules that include time course expression profiles, clustering, gene ontology enrichment analysis, differential expression analysis and comparison of experiments. All visualizations are interactive and interconnected, such that the selection of genes in one module propagates instantly to visualizations in other modules. dictyExpress currently stores the data from over 800 Dictyostelium experiments and is embedded within a general-purpose software framework for management of next-generation sequencing data. dictyExpress allows users to explore their data in a broader context by reciprocal linking with dictyBase-a repository of Dictyostelium genomic data. In addition, we introduce a companion application called GenBoard, an intuitive graphic user interface for data management and bioinformatics analysis. CONCLUSIONS dictyExpress and GenBoard enable broad adoption of next generation sequencing based inquiries by the Dictyostelium research community. Labs without the means to undertake deep sequencing projects can mine the data available to the public. The entire information flow, from raw sequence data to hypothesis testing, can be accomplished in an efficient workspace. The software framework is generalizable and represents a useful approach for any research community. To encourage more wide usage, the backend is open-source, available for extension and further development by bioinformaticians and data scientists.
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Affiliation(s)
- Miha Stajdohar
- Genialis d.o.o., Trzaska cesta 315, Ljubljana, 1000, Slovenia
| | | | - Janez Kokosar
- Genialis d.o.o., Trzaska cesta 315, Ljubljana, 1000, Slovenia
| | - Luka Jeran
- Genialis d.o.o., Trzaska cesta 315, Ljubljana, 1000, Slovenia
| | - Domen Blenkus
- Genialis d.o.o., Trzaska cesta 315, Ljubljana, 1000, Slovenia
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, 77030, TX, USA
| | - Blaz Zupan
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, 77030, TX, USA.,Faculty of Computer and Information Science, University of Ljubljana, Večna pot 113, Ljubljana, 1000, Slovenia
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25
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Liao XH, Kimmel AR. A Unique High-Throughput Assay to Identify Novel Small Molecule Inhibitors of Chemotaxis and Migration. ACTA ACUST UNITED AC 2017; 74:12.11.1-12.11.13. [PMID: 28256720 DOI: 10.1002/cpcb.17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chemotaxis and cell migration play pivotal roles in normal physiological processes such as embryogenesis, inflammation, and wound healing, as well as in pathological processes including chronic inflammatory disease and cancer metastasis. Novel chemotaxis/migration inhibitors are desirable for developing effective therapeutics and probing molecular mechanisms. We describe a fluorescence-based phenotypic assay in a 1536-well plate format for high-throughput screening of novel inhibitors of chemotaxis/migration within complex libraries of thousands of compounds. Although the assay utilizes the unique cellular response properties of Dictyostelium, the compounds identified are able to inhibit chemotaxis of mammalian cells. In addition, a parallel cell cytotoxicity counter-screen with an ATP content assay is described that eliminates cytotoxic compounds from the screen. This novel compound screening approach enables rapid identification of novel lead compounds that inhibit chemotaxis in human and other cells for drug development and research tools. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Xin-Hua Liao
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, and Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, Fujian, China
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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26
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The Long Noncoding RNA Transcriptome of Dictyostelium discoideum Development. G3-GENES GENOMES GENETICS 2017; 7:387-398. [PMID: 27932387 PMCID: PMC5295588 DOI: 10.1534/g3.116.037150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dictyostelium discoideum live in the soil as single cells, engulfing bacteria and growing vegetatively. Upon starvation, tens of thousands of amoebae enter a developmental program that includes aggregation, multicellular differentiation, and sporulation. Major shifts across the protein-coding transcriptome accompany these developmental changes. However, no study has presented a global survey of long noncoding RNAs (ncRNAs) in D. discoideum To characterize the antisense and long intergenic noncoding RNA (lncRNA) transcriptome, we analyzed previously published developmental time course samples using an RNA-sequencing (RNA-seq) library preparation method that selectively depletes ribosomal RNAs (rRNAs). We detected the accumulation of transcripts for 9833 protein-coding messenger RNAs (mRNAs), 621 lncRNAs, and 162 putative antisense RNAs (asRNAs). The noncoding RNAs were interspersed throughout the genome, and were distinct in expression level, length, and nucleotide composition. The noncoding transcriptome displayed a temporal profile similar to the coding transcriptome, with stages of gradual change interspersed with larger leaps. The transcription profiles of some noncoding RNAs were strongly correlated with known differentially expressed coding RNAs, hinting at a functional role for these molecules during development. Examining the mitochondrial transcriptome, we modeled two novel antisense transcripts. We applied yet another ribosomal depletion method to a subset of the samples to better retain transfer RNA (tRNA) transcripts. We observed polymorphisms in tRNA anticodons that suggested a post-transcriptional means by which D. discoideum compensates for codons missing in the genomic complement of tRNAs. We concluded that the prevalence and characteristics of long ncRNAs indicate that these molecules are relevant to the progression of molecular and cellular phenotypes during development.
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Malinovska L, Alberti S. Studying the Protein Quality Control System of D. discoideum Using Temperature-controlled Live Cell Imaging. J Vis Exp 2016. [PMID: 28060267 PMCID: PMC5226346 DOI: 10.3791/54730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The complex lifestyle of the social amoebae Dictyostelium discoideum makes it a valuable model for the study of various biological processes. Recently, we showed that D. discoideum is remarkably resilient to protein aggregation and can be used to gain insights into the cellular protein quality control system. However, the use of D. discoideum as a model system poses several challenges to microscopy-based experimental approaches, such as the high motility of the cells and their susceptibility to photo-toxicity. The latter proves to be especially challenging when studying protein homeostasis, as the phototoxic effects can induce a cellular stress response and thus alter to behavior of the protein quality control system. Temperature increase is a commonly used way to induce cellular stress. Here, we describe a temperature-controllable imaging protocol, which allows observing temperature-induced perturbations in D. discoideum. Moreover, when applied at normal growth temperature, this imaging protocol can also noticeably reduce photo-toxicity, thus allowing imaging with higher intensities. This can be particularly useful when imaging proteins with very low expression levels. Moreover, the high mobility of the cells often requires the acquisition of multiple fields of view to follow individual cells, and the number of fields needs to be balanced against the desired time interval and exposure time.
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Affiliation(s)
| | - Simon Alberti
- Max-Planck Institute for Molecular Cell Biology and Genetics;
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Kuburich NA, Adhikari N, Hadwiger JA. Acanthamoeba and Dictyostelium Use Different Foraging Strategies. Protist 2016; 167:511-525. [PMID: 27693864 DOI: 10.1016/j.protis.2016.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
Abstract
Amoeba often use cell movement as a mechanism to find food, such as bacteria, in their environment. The chemotactic movement of the soil amoeba Dictyostelium to folate or other pterin compounds released by bacteria is a well-documented foraging mechanism. Acanthamoeba can also feed on bacteria but relatively little is known about the mechanism(s) by which this amoeba locates bacteria. Acanthamoeba movement in the presence of folate or bacteria was analyzed in above agar assays and compared to that observed for Dictyostelium. The overall mobility of Acanthamoeba was robust like that of Dictyostelium but Acanthamoeba did not display a chemotactic response to folate. In the presence of bacteria, Acanthamoeba only showed a marginal bias in directed movement whereas Dictyostelium displayed a strong chemotactic response. A comparison of genomes revealed that Acanthamoeba and Dictyostelium share some similarities in G protein signaling components but that specific G proteins used in Dictyostelium chemotactic responses were not present in current Acanthamoeba genome sequence data. The results of this study suggest that Acanthamoeba does not use chemotaxis as the primary mechanism to find bacterial food sources and that the chemotactic responses of Dictyostelium to bacteria may have co-evolved with chemotactic responses that facilitate multicellular development.
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Affiliation(s)
- Nick A Kuburich
- Department of Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK 74078-3020, USA
| | - Nirakar Adhikari
- Department of Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK 74078-3020, USA
| | - Jeffrey A Hadwiger
- Department of Microbiology and Molecular Genetics, Oklahoma State University, 307 Life Sciences East, Stillwater, OK 74078-3020, USA
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Li CLF, Santhanam B, Webb AN, Zupan B, Shaulsky G. Gene discovery by chemical mutagenesis and whole-genome sequencing in Dictyostelium. Genome Res 2016; 26:1268-76. [PMID: 27307293 PMCID: PMC5052037 DOI: 10.1101/gr.205682.116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/17/2016] [Indexed: 11/24/2022]
Abstract
Whole-genome sequencing is a useful approach for identification of chemical-induced lesions, but previous applications involved tedious genetic mapping to pinpoint the causative mutations. We propose that saturation mutagenesis under low mutagenic loads, followed by whole-genome sequencing, should allow direct implication of genes by identifying multiple independent alleles of each relevant gene. We tested the hypothesis by performing three genetic screens with chemical mutagenesis in the social soil amoeba Dictyostelium discoideum Through genome sequencing, we successfully identified mutant genes with multiple alleles in near-saturation screens, including resistance to intense illumination and strong suppressors of defects in an allorecognition pathway. We tested the causality of the mutations by comparison to published data and by direct complementation tests, finding both dominant and recessive causative mutations. Therefore, our strategy provides a cost- and time-efficient approach to gene discovery by integrating chemical mutagenesis and whole-genome sequencing. The method should be applicable to many microbial systems, and it is expected to revolutionize the field of functional genomics in Dictyostelium by greatly expanding the mutation spectrum relative to other common mutagenesis methods.
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Affiliation(s)
- Cheng-Lin Frank Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Balaji Santhanam
- Graduate Program in Structural Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Amanda Nicole Webb
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Blaž Zupan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA; Faculty of Computer and Information Science, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Li YL, Lin ML, He SQ, Jin JF. Sphingolipid metabolism affects the anticancer effect of cisplatin. World J Transl Med 2016; 5:37-45. [DOI: 10.5528/wjtm.v5.i1.37] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/09/2015] [Accepted: 01/11/2016] [Indexed: 02/06/2023] Open
Abstract
Cisplatin, a DNA crosslinking agent, is widely used for the treatment of a variety of solid tumors. Numerous studies have demonstrated that sphingolipid metabolism, which acts as a target for cisplatin treatment, is a highly complex network that consists of sphingolipid signaling molecules and related catalytic enzymes. Ceramide (Cer), which is the central molecule of this network, has been established to induce apoptosis. However, another molecule, sphingosine-1-phosphate (S1P), exerts the opposite function, i.e., serves as a regulator of pro-survival. Other sphingolipid molecules, including dihydroceramide, ceramide-1-phosphate, glucosylceramide (GluCer), and sphingosine (Sph), or sphingolipid catalytic enzymes such as Sph kinase (SphK), Cer synthase (CerS), and S1P lyase, have also attracted considerable attention, particularly Cer, GluCer, SphK, CerS, and S1P lyase, which have been implicated in cisplatin resistance. This review summarizes specific molecules involved in sphingolipid metabolism and related catalytic enzymes affecting the anticancer effect of cisplatin, particularly in relation to induction of apoptosis and drug resistance.
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A High-Throughput, Multi-Cell Phenotype Assay for the Identification of Novel Inhibitors of Chemotaxis/Migration. Sci Rep 2016; 6:22273. [PMID: 26956526 PMCID: PMC4783656 DOI: 10.1038/srep22273] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/09/2016] [Indexed: 02/06/2023] Open
Abstract
Chemotaxis and cell migration are fundamental, universal eukaryotic processes essential for biological functions such as embryogenesis, immunity, cell renewal, and wound healing, as well as for pathogenesis of many diseases including cancer metastasis and chronic inflammation. To identify novel chemotaxis inhibitors as probes for mechanistic studies and leads for development of new therapeutics, we developed a unique, unbiased phenotypic chemotaxis-dependent Dictyostelium aggregation assay for high-throughput screening using rapid, laser-scanning cytometry. Under defined conditions, individual Dictyostelium secrete chemoattractants, migrate, and aggregate. Chemotaxis is quantified by laser-scanning cytometry with a GFP marker expressed only in cells after chemotaxis/multi-cell aggregation. We applied the assay to screen 1,280 known compounds in a 1536-well plate format and identified two chemotaxis inhibitors. The chemotaxis inhibitory activities of both compounds were confirmed in both Dictyostelium and in human neutrophils in a directed EZ-TAXIscan chemotaxis assay. The compounds were also shown to inhibit migration of two human cancer cell lines in monolayer scratch assays. This test screen demonstrated that the miniaturized assay is extremely suited for high-throughput screening of very large libraries of small molecules to identify novel classes of chemotaxis/migratory inhibitors for drug development and research tools for targeting chemotactic pathways universal to humans and other systems.
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Rodriguez-Centeno J, Sastre L. Biological Activity of the Alternative Promoters of the Dictyostelium discoideum Adenylyl Cyclase A Gene. PLoS One 2016; 11:e0148533. [PMID: 26840347 PMCID: PMC4739590 DOI: 10.1371/journal.pone.0148533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/20/2016] [Indexed: 12/01/2022] Open
Abstract
Amoebae of the Dictyostelium discoideum species form multicellular fruiting bodies upon starvation. Cyclic adenosine monophosphate (cAMP) is used as intercellular signalling molecule in cell-aggregation, cell differentiation and morphogenesis. This molecule is synthesized by three adenylyl cyclases, one of which, ACA, is required for cell aggregation. The gene coding for ACA (acaA) is transcribed from three different promoters that are active at different developmental stages. Promoter 1 is active during cell-aggregation, promoters 2 and 3 are active in prespore and prestalk tip cells at subsequent developmental stages. The biological relevance of acaA expression from each of the promoters has been studied in this article. The acaA gene was expressed in acaA-mutant cells, that do not aggregate, under control of each of the three acaA promoters. acaA expression under promoter 1 control induced cell aggregation although subsequent development was delayed, very small fruiting bodies were formed and cell differentiation genes were expressed at very low levels. Promoter 2-driven acaA expression induced the formation of small aggregates and small fruiting bodies were formed at the same time as in wild-type strains and differentiation genes were also expressed at lower levels. Expression of acaA from promoter 3 induced aggregates and fruiting bodies formation and their size and the expression of differentiation genes were more similar to that of wild-type cells. Expression of acaA from promoters 1 and 2 in AX4 cells also produced smaller structures. In conclusion, the expression of acaA under control of the aggregation-specific Promoter 1 is able to induce cell aggregation in acaA-mutant strains. Expression from promoters 2 and 3 also recovered aggregation and development although promoter 3 induced a more complete recovery of fruiting body formation.
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Affiliation(s)
| | - Leandro Sastre
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/Arturo Duperier, 4, 28029, Madrid, Spain
- CIBERER, Valencia, Spain
- * E-mail:
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Aktipis CA, Boddy AM, Jansen G, Hibner U, Hochberg ME, Maley CC, Wilkinson GS. Cancer across the tree of life: cooperation and cheating in multicellularity. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140219. [PMID: 26056363 PMCID: PMC4581024 DOI: 10.1098/rstb.2014.0219] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2015] [Indexed: 02/06/2023] Open
Abstract
Multicellularity is characterized by cooperation among cells for the development, maintenance and reproduction of the multicellular organism. Cancer can be viewed as cheating within this cooperative multicellular system. Complex multicellularity, and the cooperation underlying it, has evolved independently multiple times. We review the existing literature on cancer and cancer-like phenomena across life, not only focusing on complex multicellularity but also reviewing cancer-like phenomena across the tree of life more broadly. We find that cancer is characterized by a breakdown of the central features of cooperation that characterize multicellularity, including cheating in proliferation inhibition, cell death, division of labour, resource allocation and extracellular environment maintenance (which we term the five foundations of multicellularity). Cheating on division of labour, exhibited by a lack of differentiation and disorganized cell masses, has been observed in all forms of multicellularity. This suggests that deregulation of differentiation is a fundamental and universal aspect of carcinogenesis that may be underappreciated in cancer biology. Understanding cancer as a breakdown of multicellular cooperation provides novel insights into cancer hallmarks and suggests a set of assays and biomarkers that can be applied across species and characterize the fundamental requirements for generating a cancer.
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Affiliation(s)
- C Athena Aktipis
- Center for Evolution and Cancer, University of California San Francisco, San Francisco, CA 94143, USA Department of Psychology, Arizona State University, Tempe, AZ 85287-4501, USA Centre for Evolution and Cancer, Institute for Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Amy M Boddy
- Center for Evolution and Cancer, University of California San Francisco, San Francisco, CA 94143, USA Department of Psychology, Arizona State University, Tempe, AZ 85287-4501, USA Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Gunther Jansen
- Department of Evolutionary Ecology and Genetics, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Urszula Hibner
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Montpellier, France Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Michael E Hochberg
- Institut des Sciences de l'Evolution, CNRS UMR5554, Université Montpellier, 34095 Montpellier, France Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Carlo C Maley
- Center for Evolution and Cancer, University of California San Francisco, San Francisco, CA 94143, USA Centre for Evolution and Cancer, Institute for Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK Biodesign Institute, School of Life Sciences, Arizona State University, PO Box 8724501, Tempe, AZ 85287-4501, USA Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Gerald S Wilkinson
- Department of Biology, University of Maryland, College Park, MD 20742, USA Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin, Germany
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Root of Dictyostelia based on 213 universal proteins. Mol Phylogenet Evol 2015; 92:53-62. [PMID: 26048704 DOI: 10.1016/j.ympev.2015.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 01/03/2023]
Abstract
Dictyostelia are common soil microbes that can aggregate when starved to form multicellular fruiting bodies, a characteristic that has also led to their long history of study and widespread use as model systems. Ribosomal RNA phylogeny of Dictyostelia identified four major divisions (Groups 1-4), none of which correspond to traditional genera. Group 1 was also tentatively identified as sister lineage to the other three Groups, although not consistently or with strong support. We tested the dictyostelid root using universal protein-coding genes identified by exhaustive comparison of six completely sequenced dictyostelid genomes, which include representatives of all four major molecular Groups. A set of 213 genes are low-copy number in all genomes, present in at least one amoebozoan outgroup taxon (Acanthamoeba castellanii or Physarum polycephalum), and phylogenetically congruent. Phylogenetic analysis of a concatenation of the deduced protein sequences produces a single topology dividing Dictyostelia into two major divisions: Groups 1+2 and Groups 3+4. All clades in the tree are fully supported by maximum likelihood and Bayesian inference, and all alternative roots are unambiguously rejected by the approximately unbiased (AU) test. The 1+2, 3+4 root is also fully supported even after deleting clusters with strong individual support for this root, or concatenating all clusters with low support for alternative roots. The 213 putatively ancestral amoebozoan proteins encode a wide variety of functions including 21 KOG categories out of a total of 25. These comprehensive analyses and consistent results indicate that it is time for full taxonomic revision of Dictyostelia, which will also enable more effective exploitation of its unique potential as an evolutionary model system.
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Rosengarten RD, Beltran PR, Shaulsky G. A deep coverage Dictyostelium discoideum genomic DNA library replicates stably in Escherichia coli. Genomics 2015; 106:249-55. [PMID: 26028264 DOI: 10.1016/j.ygeno.2015.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/11/2015] [Accepted: 05/18/2015] [Indexed: 01/18/2023]
Abstract
The natural history of the amoeba Dictyostelium discoideum has inspired scientific inquiry for seventy-five years. A genetically tractable haploid eukaryote, D. discoideum appeals as a laboratory model as well. However, certain rote molecular genetic tasks, such as PCR and cloning, are difficult due to the AT-richness and low complexity of its genome. Here we report on the construction of a ~20 fold coverage D. discoideum genomic library in Escherichia coli, cloning 4-10 kilobase partial restriction fragments into a linear vector. End-sequencing indicates that most clones map to the six chromosomes in an unbiased distribution. Over 70% of these clones contain at least one complete open reading frame. We demonstrate that individual clones and library composition are stable over multiple replication cycles. Our library will enable numerous molecular biological applications and the completion of additional species' genome sequences, and suggests a path towards the long-elusive goal of genetic complementation.
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Affiliation(s)
- Rafael D Rosengarten
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Pamela R Beltran
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Rosengarten RD, Santhanam B, Fuller D, Katoh-Kurasawa M, Loomis WF, Zupan B, Shaulsky G. Leaps and lulls in the developmental transcriptome of Dictyostelium discoideum. BMC Genomics 2015; 16:294. [PMID: 25887420 PMCID: PMC4403905 DOI: 10.1186/s12864-015-1491-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/26/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Development of the soil amoeba Dictyostelium discoideum is triggered by starvation. When placed on a solid substrate, the starving solitary amoebae cease growth, communicate via extracellular cAMP, aggregate by tens of thousands and develop into multicellular organisms. Early phases of the developmental program are often studied in cells starved in suspension while cAMP is provided exogenously. Previous studies revealed massive shifts in the transcriptome under both developmental conditions and a close relationship between gene expression and morphogenesis, but were limited by the sampling frequency and the resolution of the methods. RESULTS Here, we combine the superior depth and specificity of RNA-seq-based analysis of mRNA abundance with high frequency sampling during filter development and cAMP pulsing in suspension. We found that the developmental transcriptome exhibits mostly gradual changes interspersed by a few instances of large shifts. For each time point we treated the entire transcriptome as single phenotype, and were able to characterize development as groups of similar time points separated by gaps. The grouped time points represented gradual changes in mRNA abundance, or molecular phenotype, and the gaps represented times during which many genes are differentially expressed rapidly, and thus the phenotype changes dramatically. Comparing developmental experiments revealed that gene expression in filter developed cells lagged behind those treated with exogenous cAMP in suspension. The high sampling frequency revealed many genes whose regulation is reproducibly more complex than indicated by previous studies. Gene Ontology enrichment analysis suggested that the transition to multicellularity coincided with rapid accumulation of transcripts associated with DNA processes and mitosis. Later development included the up-regulation of organic signaling molecules and co-factor biosynthesis. Our analysis also demonstrated a high level of synchrony among the developing structures throughout development. CONCLUSIONS Our data describe D. discoideum development as a series of coordinated cellular and multicellular activities. Coordination occurred within fields of aggregating cells and among multicellular bodies, such as mounds or migratory slugs that experience both cell-cell contact and various soluble signaling regimes. These time courses, sampled at the highest temporal resolution to date in this system, provide a comprehensive resource for studies of developmental gene expression.
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Affiliation(s)
- Rafael David Rosengarten
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
| | - Balaji Santhanam
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
| | - Danny Fuller
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - Mariko Katoh-Kurasawa
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
| | - William F Loomis
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - Blaz Zupan
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
- Faculty of Computer and Information Science, University of Ljubljana, Trzaska cesta 25, Ljubljana, SI-1001, Slovenia.
| | - Gad Shaulsky
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
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Catalano A, O'Day DH. Evidence for nucleolar subcompartments in Dictyostelium. Biochem Biophys Res Commun 2014; 456:901-7. [PMID: 25522879 DOI: 10.1016/j.bbrc.2014.12.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 12/09/2014] [Indexed: 10/24/2022]
Abstract
The nucleolus is a multifunctional nuclear compartment usually consisting of two to three subcompartments which represent stages of ribosomal biogenesis. It is linked to several human diseases including viral infections, cancer, and neurodegeneration. Dictyostelium is a model eukaryote for the study of fundamental biological processes as well as several human diseases however comparatively little is known about its nucleolus. Unlike most nucleoli it does not possess visible subcompartments at the ultrastructural level. Several recently identified nucleolar proteins in Dictyostelium leave the nucleolus after treatment with the rDNA transcription inhibitor actinomycin-D (AM-D). Different proteins exit in different ways, suggesting that previously unidentified nucleolar subcompartments may exist. The identification of nucleolar subcompartments would help to better understand the nucleolus in this model eukaryote. Here, we show that Dictyostelium nucleolar proteins nucleomorphin isoform NumA1 and Bud31 localize throughout the entire nucleolus while calcium-binding protein 4a localizes to only a portion, representing nucleolar subcompartment 1 (NoSC1). SWI/SNF complex member Snf12 localizes to a smaller area within NoSC1 representing a second nucleolar subcompartment, NoSC2. The nuclear/nucleolar localization signal KRKR from Snf12 localized GFP to NoSC2, and thus also appears to function as a nucleolar subcompartment localization signal. FhkA localizes to the nucleolar periphery displaying a similar pattern to that of Hsp32. Similarities between the redistribution patterns of Dictyostelium nucleolar proteins during nucleolar disruption as a result of either AM-D treatment or mitosis support these subcompartments. A model for the AM-D-induced redistribution patterns is proposed.
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Affiliation(s)
- Andrew Catalano
- Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, Ontario L5L 1C6, Canada.
| | - Danton H O'Day
- Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, Ontario L5L 1C6, Canada; Department of Cell and Systems Biology, University of Toronto, 25 Harbord St., Toronto, Ontario M5S 3G5, Canada.
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Schwebs DJ, Nguyen HN, Miller JA, Hadwiger JA. Loss of cAMP-specific phosphodiesterase rescues spore development in G protein mutant in dictyostelium. Cell Signal 2014; 26:409-18. [PMID: 24511612 DOI: 10.1016/j.cellsig.2013.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cyclic AMP (cAMP) is an important intracellular signaling molecule for many G protein-mediated signaling pathways but the specificity of cAMP signaling in cells with multiple signaling pathways is not well-understood. In Dictyostelium, at least two different G protein signaling pathways, mediated by the Gα2 and Gα4 subunits, are involved with cAMP accumulation, spore production, and chemotaxis and the stimulation of these pathways results in the activation of ERK2, a mitogen-activated protein kinase that can down regulate the cAMP-specific phosphodiesterase RegA. The regA gene was disrupted in gα2(−) and gα4(−) cells to determine if the absence of this phosphodiesterase rescues the development of these G protein mutants as it does for erk2(−) mutants. There gA(−) mutation had no major effects on developmental morphology but enriched the distribution of the Gα mutant cells to the prespore/prestalk border in chimeric aggregates. The loss of RegA function had no effect on Gα4- mediated folate chemotaxis. However, the regA gene disruption in gα4(−) cells, but not in gα2(−) cells, resulted in a substantial rescue and acceleration of spore production. This rescue in sporulation required cell autonomous signaling because the precocious sporulation could not be induced through intercellular signaling in chimeric aggregates. However, intercellular signals from regA(−) strains increased the expression of the prestalk gene ecmB and accelerated the vacuolization of stalk cells. Intercellular signaling from the gα4(−)regA(−) strain did not induce ecmA gene expression indicating cell-type specificity in the promotion of prestalk cell development. regA gene disruption in a Gα4(HC) (Gα4 overexpression) strain did not result in precocious sporulation or stalk cell development indicating that elevated Gα4 subunit expression can mask regA(−) associated phenotypes even when provided with wild-type intercellular signaling. These findings indicate that the Gα2 and Gα4-mediated pathways provide different contributions to the development of spores and stalk cells and that the absence of RegA function can bypass some but not all defects in G protein regulated spore development.
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Apostolidi M, Vourtsis DJ, Chasapis CT, Stathopoulos C, Bentrop D, Spyroulias GA. ¹H, ¹⁵N, ¹³C assignment and secondary structure determination of two domains of La protein from D. discoideum. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:47-51. [PMID: 23239108 DOI: 10.1007/s12104-012-9450-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 12/04/2012] [Indexed: 06/01/2023]
Abstract
Biosynthesis of RNA polymerase III transcripts requires binding of the La protein at their 3' end. La is an abundant nuclear RNA-binding protein which protects the nascent transcripts from 3' exonuclease degradation. Here, we report the high yield expression and preliminary structural analysis through NMR spectroscopy of two recombinant RNA binding domains (La motif and NRRM) from the La protein of Dictyostelium discoideum. Both recombinant protein constructs were well-folded and allowed for an almost complete sequence-specific assignment of the (15)N and (13)C labeled domains and their secondary structure prediction using PECAN online tool.
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Affiliation(s)
- Maria Apostolidi
- Department of Biochemistry, School of Medicine, University of Patras, 26504, Patras, Greece
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Kuwayama H, Ishida S. Biological soliton in multicellular movement. Sci Rep 2014; 3:2272. [PMID: 23893301 PMCID: PMC3725511 DOI: 10.1038/srep02272] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/03/2013] [Indexed: 11/10/2022] Open
Abstract
Solitons have been observed in various physical phenomena. Here, we show that the distinct characteristics of solitons are present in the mass cell movement of non-chemotactic mutants of the cellular slime mould Dictyostelium discoideum. During starvation, D. discoideum forms multicellular structures that differentiate into spore or stalk cells and, eventually, a fruiting body. Non-chemotactic mutant cells do not form multicellular structures; however, they do undergo mass cell movement in the form of a pulsatile soliton-like structure (SLS). We also found that SLS induction is mediated by adhesive cell-cell interactions. These observations provide novel insights into the mechanisms of biological solitons in multicellular movement.
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Affiliation(s)
- Hidekazu Kuwayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Tennodai, 1-1-1, Ibaraki 305-8572, Japan.
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A RabGAP regulates life-cycle duration via trimeric G-protein cascades in Dictyostelium discoideum. PLoS One 2013; 8:e81811. [PMID: 24349132 PMCID: PMC3859538 DOI: 10.1371/journal.pone.0081811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 10/16/2013] [Indexed: 12/22/2022] Open
Abstract
Background The life-cycle of cellular slime molds comprises chronobiologically regulated processes. During the growth phase, the amoeboid cells proliferate at a definite rate. Upon starvation, they synthesize cAMP as both first and second messengers in signalling pathways and form aggregates, migrating slugs, and fruiting bodies, consisting of spores and stalk cells, within 24 h. In Dictyostelium discoideum, because most growth-specific events cease during development, proliferative and heterochronic mutations are not considered to be interrelated and no genetic factor governing the entire life-cycle duration has ever been identified. Methodology/Principal Findings Using yeast 2-hybrid library screening, we isolated a Dictyostelium discoideum RabGAP, Dd Rbg-3, as a candidate molecule by which the Dictyostelium Gα2 subunit directs its effects. Rab GTPase-activating protein, RabGAP, acts as a negative regulator of Rab small GTPases, which orchestrate the intracellular membrane trafficking involved in cell proliferation. Deletion mutants of Dd rbg-3 exhibited an increased growth rate and a shortened developmental period, while an overexpression mutant demonstrated the opposite effects. We also show that Dd Rbg-3 interacts with 2 Gα subunits in an activity-dependent manner in vitro. Furthermore, both human and Caenorhabditis elegans rbg-3 homologs complemented the Dd rbg-3–deletion phenotype in D. discoideum, indicating that similar pathways may be generally conserved in multicellular organisms. Conclusions/Significance Our findings suggest that Dd Rbg-3 acts as a key element regulating the duration of D. discoideum life-span potentially via trimeric G-protein cascades.
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Winterhoff M, Junemann A, Nordholz B, Linkner J, Schleicher M, Faix J. The Diaphanous-related formin dDia1 is required for highly directional phototaxis and formation of properly sized fruiting bodies in Dictyostelium. Eur J Cell Biol 2013; 93:212-24. [PMID: 24331584 DOI: 10.1016/j.ejcb.2013.11.002] [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: 09/24/2013] [Revised: 11/12/2013] [Accepted: 11/14/2013] [Indexed: 11/17/2022] Open
Abstract
Diaphanous-related formins (DRFs) act as downstream effectors of Rho family GTPases and drive the formation and elongation of linear actin filaments in various cellular processes. Here we analyzed the DRF dDia1 from Dictyostelium cells. The biochemical characterization of recombinant dDia1-FH1FH2 by bulk polymerization assays and single filament TIRF microscopy revealed that dDia1 is a rather weak nucleator. Addition of any of the three Dictyostelium profilin isoforms, however, markedly accelerated formin-mediated actin filament barbed end elongation in TIRF assays. Interestingly, filament elongation was significantly faster in presence of DdPFN I (profilin I) when compared to the other two isoforms, suggesting selectivity of dDia1 for DdPFN I. Additionally, we frequently observed dissociation of the formin from growing barbed ends. These findings are consistent with dilution-induced depolymerization assays in presence of dDia1-FH1FH2 showing that dDia1 is a weak capper in comparison with heterodimeric capping protein. To study the physiological role of this formin, we created cell lines lacking dDia1 or overexpressing GFP-tagged dDia1. Of note, constitutively active dDia1 accumulated homogenously in the entire pseudopod suggesting that it controls microfilament architecture to regulate cell migration. Comparison of wild type and dDia1-null cells in random cell migration and chemotaxis toward a cAMP gradient revealed no major differences. By contrast, phototaxis of dDia1-deficient cells during the multicellular stage was markedly impaired. While wild type slugs moved with high directionality toward the light source, the trails of dDia1-null slugs displayed a characteristic V-shaped profile and deviated in angles between 50° and 60° from the path of the incident light. Possibly in conjunction with this defect, dDia1-null cells also formed substantially smaller fruiting bodies. These findings demonstrate dDia1 to be critically involved in collective cell migration during terminal differentiation.
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Affiliation(s)
- Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Alexander Junemann
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Benjamin Nordholz
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Jörn Linkner
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Michael Schleicher
- Institute for Anatomy and Cell Biology, Ludwig-Maximilians-University, 80336 München, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany.
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Annesley SJ, Chen S, Francione LM, Sanislav O, Chavan AJ, Farah C, De Piazza SW, Storey CL, Ilievska J, Fernando SG, Smith PK, Lay ST, Fisher PR. Dictyostelium, a microbial model for brain disease. Biochim Biophys Acta Gen Subj 2013; 1840:1413-32. [PMID: 24161926 DOI: 10.1016/j.bbagen.2013.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 10/05/2013] [Accepted: 10/10/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND Most neurodegenerative diseases are associated with mitochondrial dysfunction. In humans, mutations in mitochondrial genes result in a range of phenotypic outcomes which do not correlate well with the underlying genetic cause. Other neurodegenerative diseases are caused by mutations that affect the function and trafficking of lysosomes, endosomes and autophagosomes. Many of the complexities of these human diseases can be avoided by studying them in the simple eukaryotic model Dictyostelium discoideum. SCOPE OF REVIEW This review describes research using Dictyostelium to study cytopathological pathways underlying a variety of neurodegenerative diseases including mitochondrial, lysosomal and vesicle trafficking disorders. MAJOR CONCLUSIONS Generalised mitochondrial respiratory deficiencies in Dictyostelium produce a consistent pattern of defective phenotypes that are caused by chronic activation of a cellular energy sensor AMPK (AMP-activated protein kinase) and not ATP deficiency per se. Surprisingly, when individual subunits of Complex I are knocked out, both AMPK-dependent and AMPK-independent, subunit-specific phenotypes are observed. Many nonmitochondrial proteins associated with neurological disorders have homologues in Dictyostelium and are associated with the function and trafficking of lysosomes and endosomes. Conversely, some genes associated with neurodegenerative disorders do not have homologues in Dictyostelium and this provides a unique avenue for studying these mutated proteins in the absence of endogeneous protein. GENERAL SIGNIFICANCE Using the Dictyostelium model we have gained insights into the sublethal cytopathological pathways whose dysregulation contributes to phenotypic outcomes in neurodegenerative disease. This work is beginning to distinguish correlation, cause and effect in the complex network of cross talk between the various organelles involved. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- S J Annesley
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S Chen
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - L M Francione
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - O Sanislav
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - A J Chavan
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - C Farah
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S W De Piazza
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - C L Storey
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - J Ilievska
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S G Fernando
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - P K Smith
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S T Lay
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - P R Fisher
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086.
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Pharmacogenetics of resistance to Cisplatin and other anticancer drugs and the role of sphingolipid metabolism. Methods Mol Biol 2013; 983:185-204. [PMID: 23494308 DOI: 10.1007/978-1-62703-302-2_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dictyostelium discoideum has proven to be a useful lead genetic system for identifying novel genes and pathways responsible for the regulation of sensitivity to the widely used anticancer drug cisplatin. Resistance to cisplatin is a major factor limiting the efficacy of the drug in treating many types of cancer. Studies using unbiased insertional mutagenesis in D. discoideum have identified the pathway of sphingolipid metabolism as a key regulator in controlling sensitivity to cisplatin. Using the genetic tools including directed homologous recombination and ectopic gene expression available with D. discoideum has shown how pharmacological modulation of this pathway can increase sensitivity to cisplatin, and these results have been extensively translated to, and validated in, human cells. Strategies, experimental conditions, and methods are presented to enable further study of resistance to cisplatin as well as other important drugs.
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Cost HN, Noratel EF, Blumberg DD. AmpA protein functions by different mechanisms to influence early cell type specification and to modulate cell adhesion and actin polymerization in Dictyostelium discoideum. Differentiation 2013; 86:1-12. [PMID: 23911723 DOI: 10.1016/j.diff.2013.06.003] [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: 02/05/2013] [Revised: 06/03/2013] [Accepted: 06/20/2013] [Indexed: 11/16/2022]
Abstract
The Dictyostelium discoideum ampA gene encodes a multifunctional regulator protein that modulates cell-cell and cell-substrate adhesions and actin polymerization during growth and is necessary for correct cell type specification and patterning during development. Insertional inactivation of the ampA gene results in defects that define two distinct roles for the ampA gene during development. AmpA is necessary in a non-cell autonomous manner to prevent premature expression of a prespore gene marker. It is also necessary in a cell autonomous manner for the anterior like cells, which express the ampA gene, to migrate to the upper cup during culmination. It is also necessary to prevent excessive cell-cell agglutination when cells are developed in a submerged suspension culture. Here, we demonstrate that a supernatant source of AmpA protein, added extracellularly, can prevent the premature mis-expression of the prespore marker. Synthetic oligopeptides are used to identify the domain of the AmpA protein that is important for preventing cells from mis-expressing the prespore gene. We further demonstrate that a factor capable of inducing additional cells to express the prespore gene marker accumulates extracellularly in the absence of AmpA protein. While the secreted AmpA acts extracellularly to suppress prespore gene expression, the effects of AmpA on cell agglutination and on actin polymerization in growing cells are not due to an extracellular role of secreted AmpA protein. Rather, these effects appear to reflect a distinct cell autonomous role of the ampA gene. Finally, we show that secretion of AmpA protein is brought about by elevating the levels of expression of ampA so that the protein accumulates to an excessive level.
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Affiliation(s)
- Hoa N Cost
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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Junemann A, Winterhoff M, Nordholz B, Rottner K, Eichinger L, Gräf R, Faix J. ForC lacks canonical formin activity but bundles actin filaments and is required for multicellular development of Dictyostelium cells. Eur J Cell Biol 2013; 92:201-12. [PMID: 23906540 DOI: 10.1016/j.ejcb.2013.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/02/2013] [Accepted: 07/03/2013] [Indexed: 01/28/2023] Open
Abstract
Diaphanous-related formins (DRFs) drive the nucleation and elongation of linear actin filaments downstream of Rho GTPase signalling pathways. Dictyostelium formin C (ForC) resembles a DRF, except that it lacks a genuine formin homology domain 1 (FH1), raising the questions whether or not ForC can nucleate and elongate actin filaments. We found that a recombinant ForC-FH2 fragment does not nucleate actin polymerization, but moderately decreases the rate of spontaneous actin assembly and disassembly, although the barbed-end elongation rate in the presence of the formin was not markedly changed. However, the protein bound to and crosslinked actin filaments into loose bundles of mixed polarity. Furthermore, ForC is an important regulator of morphogenesis since ForC-null cells are severely impaired in development resulting in the formation of aberrant fruiting bodies. Immunoblotting revealed that ForC is absent during growth, but becomes detectable at the onset of early aggregation when cells chemotactically stream together to form a multicellular organism, and peaks around the culmination stage. Fluorescence microscopy of cells ectopically expressing a GFP-tagged, N-terminal ForC fragment showed its prominent accumulation in the leading edge, suggesting that ForC may play a role in cell migration. In agreement with its expression profile, no defects were observed in random migration of vegetative mutant cells. Notably, chemotaxis of starved cells towards a source of cAMP was severely impaired as opposed to control. This was, however, largely due to a marked developmental delay of the mutant, as evidenced by the expression profile of the early developmental marker csA. In line with this, chemotaxis was almost restored to wild type levels after prolonged starvation. Finally, we observed a complete failure of phototaxis due to abolished slug formation and a massive reduction of spores consistent with forC promoter-driven expression of β-galactosidase in prespore cells. Together, these findings demonstrate ForC to be critically involved in signalling of the cytoskeleton during various stages of development.
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Affiliation(s)
- Alexander Junemann
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
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Catalano A, O'Day DH. Rad53 homologue forkhead-associated kinase A (FhkA) and Ca2+-binding protein 4a (CBP4a) are nucleolar proteins that differentially redistribute during mitosis in Dictyostelium. Cell Div 2013; 8:4. [PMID: 23587254 PMCID: PMC3637376 DOI: 10.1186/1747-1028-8-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 04/05/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND During mitosis most nucleolar proteins redistribute to other locales providing an opportunity to study the relationship between nucleolar protein localization and function. Dictyostelium is a model organism for the study of several fundamental biological processes and human diseases but only two nucleolar proteins have been studied during mitosis: NumA1 and Snf12. Both of them are linked to the cell cycle. To acquire a better understanding of nucleolar protein localization and dynamics in Dictyostelium we studied the nucleolar localization of two additional proteins during mitosis: Snf12-linked forkhead-associated kinase A (FhkA), which is involved in the cell cycle, and Ca2+-binding protein 4a (CBP4a), which is a binding partner of NumA1. METHODS Polyclonal antibodies were produced in-house. Cells were fixed and probed with either anti-FhkA or anti-CBP4a in order to determine cellular localization during interphase and throughout the stages of mitosis. Colocalization with DAPI nuclear stain allowed us to determine the location of the nucleus and nucleolus while colocalization with anti-α-tubulin allowed us to determine the cell cycle stage. RESULTS Here we verify two novel nucleolar proteins, Rad53 homologue FhkA which localized around the edge of the nucleolus and CBP4a which was detected throughout the entire nucleolus. Treatment with the Ca2+ chelator BAPTA (5 mM) showed that the nucleolar localization of CBP4a is Ca2+-dependent. In response to actinomycin D (0.05 mg/mL) CBP4a disappeared from the nucleolus while FhkA protruded from the nucleus, eventually pinching off as cytoplasmic circles. FhkA and CBP4a redistributed differently during mitosis. FhkA redistributed throughout the entire cell and at the nuclear envelope region from prometaphase through telophase. In contrast, during prometaphase CBP4a relocated to many large, discrete "CBP4a islands" throughout the nucleoplasm. Two larger "CBP4a islands" were also detected specifically at the metaphase plate region. CONCLUSIONS FhkA and CBP4a represent the sixth and seventh nucleolar proteins that have been verified to date in Dictyostelium and the third and fourth studied during mitosis. The protein-specific distributions of all of these nucleolar proteins during interphase and mitosis provide unique insight into nucleolar protein dynamics in this model organism setting the stage for future work.
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Affiliation(s)
- Andrew Catalano
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord st,, Toronto, ON M5S 3G5, Canada.
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Galardi-Castilla M, Fernandez-Aguado I, Suarez T, Sastre L. Mef2A, a homologue of animal Mef2 transcription factors, regulates cell differentiation in Dictyostelium discoideum. BMC DEVELOPMENTAL BIOLOGY 2013; 13:12. [PMID: 23577638 PMCID: PMC3640940 DOI: 10.1186/1471-213x-13-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/05/2013] [Indexed: 01/28/2023]
Abstract
Background Transcription factors from the MADS-box family play a relevant role in cell differentiation and development and include the animal SRF (serum response factor) and MEF2 (myocyte enhancer factor 2) proteins. The social amoeba Dictyostelium discoideum contains four genes coding for MADS-box transcription factors, two of these genes code for proteins that are more similar to SRF, and the other two code for proteins that are more similar to MEF2 animal factors. Results The biological function of one of the two genes that codes for MEF2-related proteins, a gene known as mef2A, is described in this article. This gene is expressed under the transcriptional control of two alternative promoters in growing cells, and its expression is induced during development in prespore cells. Mutant strains where the mef2A gene has been partially deleted were generated to study its biological function. The mutant strains showed reduced growth when feeding on bacteria and were able to develop and form fruiting bodies, but spore production was significantly reduced. A study of developmental markers showed that prespore cells differentiation was impaired in the mutant strains. When mutant and wild-type cells were set to develop in chimeras, mutant spores were underrepresented in the fruiting bodies. The mutant cells were also unable to form spores in vitro. In addition, mutant cells also showed a poor contribution to the formation of the tip-organizer and the upper region of slugs and culminant structures. In agreement with these observations, a comparison of the genes transcribed by mutant and wild-type strains during development indicated that prestalk gene expression was enhanced, while prespore gene expression decreased in the mef2A- strain. Conclusions Our data shows that mef2A plays a role in cell differentiation in D. discoideum and modulates the expression of prespore and prestalk genes.
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Affiliation(s)
- María Galardi-Castilla
- Instituto de Investigaciones Biomédicas de Madrid (Biomedical Research Institute of Madrid), CSIC/UAM, C/Arturo Duperier 4, 28029 Madrid, Spain
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Secretory lysosomes in Dictyostelium: visualization, characterization, and dynamics. Methods Mol Biol 2013; 983:445-59. [PMID: 23494323 DOI: 10.1007/978-1-62703-302-2_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Dictyostelium discoideum is a unicellular eukaryotic model largely used for the study of the endocytic pathway, mainly due to its high resemblance to the mammalian pathway. Over the last years, Dictyostelium has been increasingly employed for investigating the biogenesis and secretion of secretory lysosomes, given its advantage over mammalian cells. Here we describe protocols for determination of ionic concentration and rates of maturation and exocytosis of these compartments.
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McQuade KJ, Nakajima A, Ilacqua AN, Shimada N, Sawai S. The green tea catechin epigallocatechin gallate (EGCG) blocks cell motility, chemotaxis and development in Dictyostelium discoideum. PLoS One 2013; 8:e59275. [PMID: 23516620 PMCID: PMC3597604 DOI: 10.1371/journal.pone.0059275] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 02/13/2013] [Indexed: 12/31/2022] Open
Abstract
Catechins, flavanols found at high levels in green tea, have received significant attention due to their potential health benefits related to cancer, autoimmunity and metabolic disease, but little is known about the mechanisms by which these compounds affect cellular behavior. Here, we assess whether the model organism Dictyostelium discoideum is a useful tool with which to characterize the effects of catechins. Epigallocatechin gallate (EGCG), the most abundant and potent catechin in green tea, has significant effects on the Dictyostelium life cycle. In the presence of EGCG aggregation is delayed, cells do not stream and development is typically stalled at the loose aggregate stage. The developmental effects very likely result from defects in motility, as EGCG reduces both random movement and chemotaxis of Dictyostelium amoebae. These results suggest that catechins and their derivatives may be useful tools with which to better understand cell motility and development in Dictyostelium and that this organism is a useful model to further characterize the activities of catechins.
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Affiliation(s)
- Kyle J McQuade
- Department of Biological Sciences, Colorado Mesa University, Grand Junction, Colorado, United States of America.
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