1
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Takamori S, Mimura H, Osaki T, Kondo T, Shintomi M, Shintomi K, Ohsugi M, Takeuchi S. Nuclear Assembly in Giant Unilamellar Vesicles Encapsulating Xenopus Egg Extract. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2025:e2412126. [PMID: 40390663 DOI: 10.1002/smll.202412126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2024] [Revised: 03/17/2025] [Indexed: 05/21/2025]
Abstract
The reconstitution of a cell nucleus in a lipid bilayer-enclosed synthetic cell makes great strides in bottom-up synthetic biology. In this study, a method for assembling a nucleus in giant unilamellar vesicles (GUVs) is proposed. To induce reconstitution of the nucleus, the interphase egg extract of African clawed frogs Xenopus laevis is utilized, known as a biochemically controllable cell-free system capable of transforming an added sperm chromatin into a nucleus in vitro. The GUV formation efficiency is enhanced by the inverted emulsion method through incorporating prolonged waiting time and adding chloroform into lipid-dispersed oil, facilitating subsequent nuclear assembly reactions in the GUVs. Characterization of nucleus-like structures formed in the GUVs revealed the presence of dense DNA and accumulated GFP-NLS in the structure, indicative of functional nuclear import. Immunostaining further validated the presence of nuclear pore complexes on the surfaces of these nucleus-like structures. The approach offers a versatile platform for constructing artificial cellular systems that closely mimic eukaryotic cells.
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Affiliation(s)
- Sho Takamori
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan
| | - Hisatoshi Mimura
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan
| | - Toshihisa Osaki
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan
| | - Tomo Kondo
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8902, Japan
| | - Miyuki Shintomi
- Life Science Network, The University of Tokyo, Meguro-ku, Tokyo, 153-8902, Japan
| | - Keishi Shintomi
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, 351-0198, Japan
| | - Miho Ohsugi
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, 153-8902, Japan
| | - Shoji Takeuchi
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
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2
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Rombouts J, Tavella F, Vandervelde A, Phong C, Ferrell JE, Yang Q, Gelens L. Mechanistic origins of temperature scaling in the early embryonic cell cycle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.12.24.630245. [PMID: 39763717 PMCID: PMC11703202 DOI: 10.1101/2024.12.24.630245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2025]
Abstract
Temperature profoundly impacts organismal physiology and ecological dynamics, particularly affecting ectothermic species and making them especially vulnerable to climate changes. Although complex physiological processes usually involve dozens of enzymes, empirically it is found that the rates of these processes often obey the Arrhenius equation, which was originally proposed for individual chemical reactions. Here we have examined the temperature scaling of the early embryonic cell cycle, with the goal of understanding why the Arrhenius equation approximately holds and why it breaks down at temperature extremes. Using experimental data from Xenopus laevis, Xenopus tropicalis, and Danio rerio, plus published data from Caenorhabditis elegans, Caenorhabditis briggsae, and Drosophila melanogaster, we find that the apparent activation energies (E a values) for the early embryonic cell cycle for diverse ectotherms are all similar, 75 ± 7 kJ/mol (mean ± std.dev., n = 6), which corresponds to aQ 10 value at 20°C of 2.8 ± 0.2 (mean ± std.dev., n = 6). Using computational models, we find that the approximate Arrhenius scaling and the deviations from it at high and low temperatures can be accounted for by biphasic temperature scaling in critical individual components of the cell cycle oscillator circuit, by imbalances in theE a values for different partially rate-determining enzymes, or by a combination of both. Experimental studies of cycling Xenopus extracts indicate that both of these mechanisms contribute to the general scaling of temperature, and in vitro studies of individual cell cycle regulators confirm that there is in fact a substantial imbalance in theirE a values. These findings provide mechanistic insights into the dynamic interplay between temperature and complex biochemical processes, and into why biological systems fail at extreme temperatures.
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Affiliation(s)
- Jan Rombouts
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium
- Cell Biology and Biophysics Unit and Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Franco Tavella
- Department of Physics /Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alexandra Vandervelde
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium
| | - Connie Phong
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
| | - Qiong Yang
- Department of Physics /Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium
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3
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Choi AA, Zhou CY, Tabo A, Heald R, Xu K. Single-molecule diffusivity quantification in Xenopus egg extracts elucidates physicochemical properties of the cytoplasm. Proc Natl Acad Sci U S A 2024; 121:e2411402121. [PMID: 39636857 DOI: 10.1073/pnas.2411402121] [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: 06/08/2024] [Accepted: 11/10/2024] [Indexed: 12/07/2024] Open
Abstract
The living cell creates a unique internal molecular environment that is challenging to characterize. By combining single-molecule displacement/diffusivity mapping (SMdM) with physiologically active extracts prepared from Xenopus laevis eggs, we sought to elucidate molecular properties of the cytoplasm. Quantification of the diffusion coefficients of 15 diverse proteins in extract showed that, compared to in water, negatively charged proteins diffused ~50% slower, while diffusion of positively charged proteins was reduced by ~80 to 90%. Adding increasing concentrations of salt progressively alleviated the suppressed diffusion observed for positively charged proteins, signifying electrostatic interactions within a predominately negatively charged macromolecular environment. To investigate the contribution of RNA, an abundant, negatively charged component of cytoplasm, extracts were treated with ribonuclease, which resulted in low diffusivity domains indicative of aggregation, likely due to the liberation of positively charged RNA-binding proteins such as ribosomal proteins, since this effect could be mimicked by adding positively charged polypeptides. Interestingly, in extracts prepared under typical conditions that inhibit actin polymerization, negatively charged proteins of different sizes showed similar diffusivity suppression consistent with our separately measured 2.22-fold higher viscosity of extract over water. Restoring or enhancing actin polymerization progressively suppressed the diffusion of larger proteins, recapitulating behaviors observed in cells. Together, these results indicate that molecular interactions in the crowded cell are defined by an overwhelmingly negatively charged macromolecular environment containing cytoskeletal networks.
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Affiliation(s)
- Alexander A Choi
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Coral Y Zhou
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Ayana Tabo
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, CA 94720
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4
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Puls O, Ruiz-Reynés D, Tavella F, Jin M, Kim Y, Gelens L, Yang Q. Spatial heterogeneity accelerates phase-to-trigger wave transitions in frog egg extracts. Nat Commun 2024; 15:10455. [PMID: 39622792 PMCID: PMC11612452 DOI: 10.1038/s41467-024-54752-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 11/19/2024] [Indexed: 12/06/2024] Open
Abstract
Cyclin-dependent kinase 1 (Cdk1) activity rises and falls throughout the cell cycle: a cell-autonomous process called mitotic oscillations. Mitotic oscillators can synchronize when spatially coupled, facilitating rapid, synchronous divisions in large early embryos of Drosophila (~0.5 mm) and Xenopus (~1.2 mm). Diffusion alone cannot achieve such long-range coordination. Instead, studies proposed mitotic waves-phase and trigger waves-as mechanisms of the coordination. How waves establish over time remains unclear. Using Xenopus laevis egg extracts and a Cdk1 Förster resonance energy transfer sensor, we observe a transition from phase to trigger wave dynamics in initially homogeneous cytosol. Spatial heterogeneity promotes this transition. Adding nuclei accelerates entrainment. The system transitions almost immediately when driven by metaphase-arrested extracts. Numerical simulations suggest phase waves appear transiently as trigger waves take time to entrain the system. Therefore, we show that both waves belong to a single biological process capable of coordinating the cell cycle over long distances.
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Affiliation(s)
- Owen Puls
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Daniel Ruiz-Reynés
- Laboratory of Dynamics in Biological Systems, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
- IFISC (CSIC-UIB). Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122, Palma de Mallorca, Spain
| | - Franco Tavella
- Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Minjun Jin
- Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yeonghoon Kim
- Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium.
| | - Qiong Yang
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA.
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5
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Choi AA, Zhou CY, Tabo A, Heald R, Xu K. Single-molecule diffusivity quantification in Xenopus egg extracts elucidates physicochemical properties of the cytoplasm. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.24.609541. [PMID: 39253443 PMCID: PMC11383024 DOI: 10.1101/2024.08.24.609541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
The living cell creates a unique internal molecular environment that is challenging to characterize. By combining single-molecule displacement/diffusivity mapping (SM d M) with physiologically active extracts prepared from Xenopus laevis eggs, we sought to elucidate molecular properties of the cytoplasm. Quantification of the diffusion coefficients of 15 diverse proteins in extract showed that, compared to in water, negatively charged proteins diffused ∼50% slower, while diffusion of positively charged proteins was reduced by ∼80-90%. Adding increasing concentrations of salt progressively alleviated the suppressed diffusion observed for positively charged proteins, signifying electrostatic interactions within a predominately negatively charged macromolecular environment. To investigate the contribution of RNA, an abundant, negatively charged component of cytoplasm, extracts were treated with ribonuclease, which resulted in low diffusivity domains indicative of aggregation, likely due to the liberation of positively charged RNA-binding proteins such as ribosomal proteins, since this effect could be mimicked by adding positively charged polypeptides. Interestingly, negatively charged proteins of different sizes showed similar diffusivity suppression in extract, which are typically prepared under conditions that inhibit actin polymerization. Restoring or enhancing actin polymerization progressively suppressed the diffusion of larger proteins, recapitulating behaviors observed in cells. Together, these results indicate that molecular interactions in the crowded cell are defined by an overwhelmingly negatively charged macromolecular environment containing cytoskeletal networks. Significance Statement The complex intracellular molecular environment is notably challenging to elucidate and recapitulate. Xenopus egg extracts provide a native yet manipulatable cytoplasm model. Through single-molecule microscopy, here we decipher the cytoplasmic environment and molecular interactions by examining the diffusion patterns of diverse proteins in Xenopus egg extracts with strategic manipulations. These experiments reveal an overwhelmingly negatively charged macromolecular environment with crosslinked meshworks, offering new insight into the inner workings of the cell.
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6
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Huang JH, Chen Y, Huang WYC, Tabatabaee S, Ferrell JE. Robust trigger wave speed in Xenopus cytoplasmic extracts. Nat Commun 2024; 15:5782. [PMID: 38987269 PMCID: PMC11237086 DOI: 10.1038/s41467-024-50119-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 07/01/2024] [Indexed: 07/12/2024] Open
Abstract
Self-regenerating trigger waves can spread rapidly through the crowded cytoplasm without diminishing in amplitude or speed, providing consistent, reliable, long-range communication. The macromolecular concentration of the cytoplasm varies in response to physiological and environmental fluctuations, raising the question of how or if trigger waves can robustly operate in the face of such fluctuations. Using Xenopus extracts, we find that mitotic and apoptotic trigger wave speeds are remarkably invariant. We derive a model that accounts for this robustness and for the eventual slowing at extremely high and low cytoplasmic concentrations. The model implies that the positive and negative effects of cytoplasmic concentration (increased reactant concentration vs. increased viscosity) are nearly precisely balanced. Accordingly, artificially maintaining a constant cytoplasmic viscosity during dilution abrogates this robustness. The robustness in trigger wave speeds may contribute to the reliability of the extremely rapid embryonic cell cycle.
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Affiliation(s)
- Jo-Hsi Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Yuping Chen
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - William Y C Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Saman Tabatabaee
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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7
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Garfinkel AM, Ilker E, Miyazawa H, Schmeisser K, Tennessen JM. Historic obstacles and emerging opportunities in the field of developmental metabolism - lessons from Heidelberg. Development 2024; 151:dev202937. [PMID: 38912552 PMCID: PMC11299503 DOI: 10.1242/dev.202937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
The field of developmental metabolism is experiencing a technological revolution that is opening entirely new fields of inquiry. Advances in metabolomics, small-molecule sensors, single-cell RNA sequencing and computational modeling present new opportunities for exploring cell-specific and tissue-specific metabolic networks, interorgan metabolic communication, and gene-by-metabolite interactions in time and space. Together, these advances not only present a means by which developmental biologists can tackle questions that have challenged the field for centuries, but also present young scientists with opportunities to define new areas of inquiry. These emerging frontiers of developmental metabolism were at the center of a highly interactive 2023 EMBO workshop 'Developmental metabolism: flows of energy, matter, and information'. Here, we summarize key discussions from this forum, emphasizing modern developmental biology's challenges and opportunities.
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Affiliation(s)
- Alexandra M. Garfinkel
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT 06510, USA
| | - Efe Ilker
- Max Planck Institute for the Physics of Complex Systems, Dresden 01187, Germany
| | - Hidenobu Miyazawa
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Kathrin Schmeisser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden 01307, Germany
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8
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Li Z, Wang S, Sun M, Jin M, Khain D, Yang Q. Comprehensive Parameter Space Mapping of Cell Cycle Dynamics under Network Perturbations. ACS Synth Biol 2024; 13:804-815. [PMID: 38420905 DOI: 10.1021/acssynbio.3c00631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Studies of quantitative systems and synthetic biology have extensively utilized models to interpret data, make predictions, and guide experimental designs. However, models often simplify complex biological systems and lack experimentally validated parameters, making their reliability in perturbed systems unclear. Here, we developed a droplet-based synthetic cell system to continuously tune parameters at the single-cell level in multiple dimensions with full dynamic ranges, providing an experimental framework for global parameter space scans. We systematically perturbed a cell-cycle oscillator centered on cyclin-dependent kinase (Cdk1), enabling comprehensive mapping of period landscapes in response to network perturbations. The data allowed us to challenge existing models and refine a new model that matches the observed response. Our analysis demonstrated that Cdk1 positive feedback inhibition restricts the cell cycle frequency range, confirming model predictions; furthermore, it revealed new cellular responses to the inhibition of the Cdk1-counteracting phosphatase PP2A: monomodal or bimodal distributions across varying inhibition levels, underscoring the complex nature of cell cycle regulation that can be explained by our model. This comprehensive perturbation platform may be generalizable to exploring other complex dynamic systems.
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Affiliation(s)
- Zhengda Li
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Shiyuan Wang
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Meng Sun
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Minjun Jin
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Daniel Khain
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
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9
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Puls O, Ruiz-Reynés D, Tavella F, Jin M, Kim Y, Gelens L, Yang Q. Mitotic waves in frog egg extracts: Transition from phase waves to trigger waves. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576267. [PMID: 38496576 PMCID: PMC10942321 DOI: 10.1101/2024.01.18.576267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Cyclin-dependent kinase 1 (Cdk1) activity rises and falls throughout the cell cycle, a cell-autonomous process known as mitotic oscillations. These oscillators can synchronize when spatially coupled, providing a crucial foundation for rapid synchronous divisions in large early embryos like Drosophila (~ 0.5 mm) and Xenopus (~ 1.2 mm). While diffusion alone cannot achieve such long-range coordination, recent studies have proposed two types of mitotic waves, phase and trigger waves, to explain the phenomena. How the waves establish over time for efficient spatial coordination remains unclear. Using Xenopus laevis egg extracts and a Cdk1 FRET sensor, we observe a transition from phase waves to a trigger wave regime in an initially homogeneous cytosol. Adding nuclei accelerates such transition. Moreover, the system transitions almost immediately to this regime when externally driven by metaphase-arrested extracts from the boundary. Employing computational modeling, we pinpoint how wave nature, including speed-period relation, depends on transient dynamics and oscillator properties, suggesting that phase waves appear transiently due to the time required for trigger waves to entrain the system and that spatial heterogeneity promotes entrainment. Therefore, we show that both waves belong to a single biological process capable of coordinating the cell cycle over long distances.
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Affiliation(s)
- Owen Puls
- Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Daniel Ruiz-Reynés
- Laboratory of Dynamics in Biological Systems, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
- IFISC (CSIC-UIB). Instituto de Física Interdisciplinar y Sistemas Complejos, E-07122 Palma de Mallorca, Spain
| | - Franco Tavella
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Minjun Jin
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yeonghoon Kim
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Qiong Yang
- Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
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10
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Huang WYC, Ferrell JE, Cheng X. Measuring Molecular Diffusion in Self-Organizing Xenopus Extracts by Fluorescence Correlation Spectroscopy. Methods Mol Biol 2024; 2740:107-115. [PMID: 38393471 DOI: 10.1007/978-1-0716-3557-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
The cytoplasm is densely packed with macromolecules and organelles, displaying viscoelastic properties at various scales. How biochemical reactions function efficiently enough in a seemingly jammed environment remains elusive. Cell-free Xenopus laevis extracts represent a powerful system for investigating the biochemistry and biophysics of living systems. Here we present a protocol for characterizing macromolecular diffusion in self-organizing cytoplasmic extracts using fluorescence correlation spectroscopy (FCS), which measures the motions on a distance scale of ~200 nm. The method can also be used to characterize diffusion in the cytoplasm as it progresses through different phases of the cell cycle.
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Affiliation(s)
- William Y C Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Xianrui Cheng
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
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11
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Huang JH, Chen Y, Huang WYC, Tabatabaee S, Ferrell JE. Robust trigger wave speed in Xenopus cytoplasmic extracts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573127. [PMID: 38187567 PMCID: PMC10769400 DOI: 10.1101/2023.12.22.573127] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Self-regenerating trigger waves can spread rapidly through the crowded cytoplasm without diminishing in amplitude or speed, providing consistent, reliable, long-range communication. The macromolecular concentration of the cytoplasm varies in response to physiological and environmental fluctuations, raising the question of how or if trigger waves can robustly operate in the face of such fluctuations. Using Xenopus extracts, we found that mitotic and apoptotic trigger wave speeds are remarkably invariant. We derived a model that accounts for this robustness and for the eventual slowing at extremely high and low cytoplasmic concentrations. The model implies that the positive and negative effects of cytoplasmic concentration (increased reactant concentration vs. increased viscosity) are nearly precisely balanced. Accordingly, artificially maintaining a constant cytoplasmic viscosity during dilution abrogates this robustness. The robustness in trigger wave speeds may contribute to the reliability of the extremely rapid embryonic cell cycle.
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Affiliation(s)
- Jo-Hsi Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
- These authors contributed equally
| | - Yuping Chen
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
- These authors contributed equally
| | - William Y C Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
| | - Saman Tabatabaee
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 943055307, USA
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12
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Zhong Z, Lin W, Qin BW. Modulating Biological Rhythms: A Noncomputational Strategy Harnessing Nonlinearity and Decoupling Frequency and Amplitude. PHYSICAL REVIEW LETTERS 2023; 131:138401. [PMID: 37832005 DOI: 10.1103/physrevlett.131.138401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/17/2023] [Accepted: 08/30/2023] [Indexed: 10/15/2023]
Abstract
Understanding and achieving concurrent modulation of amplitude and frequency, particularly adjusting one quantity and simultaneously sustaining the other at an invariant level, are of paramount importance for complex biophysical systems, including the signal pathway where different frequency indicates different upstream signal yielding a certain downstream physiological function while different amplitude further determines different efficacy of a downstream output. However, such modulators with clearly described and universally valid mechanisms are still lacking. Here, we rigorously propose an easy-to-use control strategy containing only one or two steps, leveraging the nonlinearity in the modulated systems to decouple frequency and amplitude in a noncomputational manner. The strategy's efficacy is demonstrated using representative biochemical systems and, thus, it could be potentially applicable to modulating rhythms in experiments of biochemistry and synthetic biology.
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Affiliation(s)
- Zhaoyue Zhong
- School of Mathematical Sciences and Shanghai Center for Mathematical Sciences, Fudan University, 200433 Shanghai, China
| | - Wei Lin
- School of Mathematical Sciences and Shanghai Center for Mathematical Sciences, Fudan University, 200433 Shanghai, China
- Research Institute of Intelligent Complex Systems, Fudan University, 200433 Shanghai, China
- Shanghai Artificial Intelligence Laboratory, 200232 Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Brain Science, Fudan University, 200032 Shanghai, China
| | - Bo-Wei Qin
- Research Institute of Intelligent Complex Systems, Fudan University, 200433 Shanghai, China
- Shanghai Artificial Intelligence Laboratory, 200232 Shanghai, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Brain Science, Fudan University, 200032 Shanghai, China
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13
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Rombouts J, Verplaetse S, Gelens L. The ups and downs of biological oscillators: a comparison of time-delayed negative feedback mechanisms. J R Soc Interface 2023; 20:20230123. [PMID: 37376871 PMCID: PMC10300510 DOI: 10.1098/rsif.2023.0123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
Many biochemical oscillators are driven by the periodic rise and fall of protein concentrations or activities. A negative feedback loop underlies such oscillations. The feedback can act on different parts of the biochemical network. Here, we mathematically compare time-delay models where the feedback affects production and degradation. We show a mathematical connection between the linear stability of the two models, and derive how both mechanisms impose different constraints on the production and degradation rates that allow oscillations. We show how oscillations are affected by the inclusion of a distributed delay, of double regulation (acting on production and degradation) and of enzymatic degradation.
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Affiliation(s)
- Jan Rombouts
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Sarah Verplaetse
- Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Lendert Gelens
- Department of Cellular and Molecular Medicine, KU Leuven, Belgium
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14
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Chen M, Wang R. Computational analysis of synergism in small networks with different logic. J Biol Phys 2023; 49:1-27. [PMID: 36580168 PMCID: PMC9958226 DOI: 10.1007/s10867-022-09620-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022] Open
Abstract
Cell fate decision processes are regulated by networks which contain different molecules and interactions. Different network topologies may exhibit synergistic or antagonistic effects on cellular functions. Here, we analyze six most common small networks with regulatory logic AND or OR, trying to clarify the relationship between network topologies and synergism (or antagonism) related to cell fate decisions. We systematically examine the contribution of both network topologies and regulatory logic to the cell fate synergism by bifurcation and combinatorial perturbation analysis. Initially, under a single set of parameters, the synergism of three types of networks with AND and OR logic is compared. Furthermore, to consider whether these results depend on the choices of parameter values, statistics on the synergism of five hundred parameter sets is performed. It is shown that the results are not sensitive to parameter variations, indicating that the synergy or antagonism mainly depends on the network topologies rather than the choices of parameter values. The results indicate that the topology with "Dual Inhibition" shows good synergism, while the topology with "Dual Promotion" or "Hybrid" shows antagonism. The results presented here may help us to design synergistic networks based on network structure and regulation combinations, which has promising implications for cell fate decisions and drug combinations.
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Affiliation(s)
- Menghan Chen
- Department of Mathematics, Shanghai University, Shanghai, 200444, China
| | - Ruiqi Wang
- Department of Mathematics, Shanghai University, Shanghai, 200444, China.
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15
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Chen P, Levy DL. Regulation of organelle size and organization during development. Semin Cell Dev Biol 2023; 133:53-64. [PMID: 35148938 PMCID: PMC9357868 DOI: 10.1016/j.semcdb.2022.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 12/11/2022]
Abstract
During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.
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Affiliation(s)
- Pan Chen
- Institute of Biochemistry and Molecular Biology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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16
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Maryu G, Yang Q. Nuclear-cytoplasmic compartmentalization of cyclin B1-Cdk1 promotes robust timing of mitotic events. Cell Rep 2022; 41:111870. [PMID: 36577372 DOI: 10.1016/j.celrep.2022.111870] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/15/2022] [Accepted: 12/01/2022] [Indexed: 12/28/2022] Open
Abstract
The cyclin-dependent kinase (Cdk1) oscillator is widely characterized in homogenized cytosolic extracts, leaving unclear the impact of nucleocytoplasmic compartmentalization. Here, by developing a Förster resonance energy transfer (FRET) biosensor, we track Cdk1 spatiotemporal dynamics in reconstituted cells with or without side by side and find compartmentalization significantly modulates clock properties previously found in bulk studies. Although nucleus-absent cells display highly tunable frequency, the nucleus-present cells maintain constant frequency against cyclin B1 variations. Despite high expression variability, cyclin degraded within the same duration, enabling a robust mitotic phase. Moreover, Cdk1 and cyclin B1 cycle rigorously out-of-phase, ensuring wide phase-plane orbits, essential for oscillation robustness. Although Cdk1 in homogeneous extracts is well known for delayed switch-like activation, we find active cyclin B1-Cdk1 accumulates in nuclei, without delay, until the nuclear envelope breakdown (NEB) when another abrupt activation triggers anaphase. Cdk1 biphasic activation and spatial compartmentalization may together coordinate the accurate ordering of different downstream events.
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Affiliation(s)
- Gembu Maryu
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA.
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17
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Liu S, Tan C, Tyers M, Zetterberg A, Kafri R. What programs the size of animal cells? Front Cell Dev Biol 2022; 10:949382. [PMID: 36393871 PMCID: PMC9665425 DOI: 10.3389/fcell.2022.949382] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/07/2022] [Indexed: 01/19/2023] Open
Abstract
The human body is programmed with definite quantities, magnitudes, and proportions. At the microscopic level, such definite sizes manifest in individual cells - different cell types are characterized by distinct cell sizes whereas cells of the same type are highly uniform in size. How do cells in a population maintain uniformity in cell size, and how are changes in target size programmed? A convergence of recent and historical studies suggest - just as a thermostat maintains room temperature - the size of proliferating animal cells is similarly maintained by homeostatic mechanisms. In this review, we first summarize old and new literature on the existence of cell size checkpoints, then discuss additional advances in the study of size homeostasis that involve feedback regulation of cellular growth rate. We further discuss recent progress on the molecules that underlie cell size checkpoints and mechanisms that specify target size setpoints. Lastly, we discuss a less-well explored teleological question: why does cell size matter and what is the functional importance of cell size control?
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Affiliation(s)
- Shixuan Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, United States
| | - Ceryl Tan
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, University of Montréal, Montréal, QC, Canada
| | - Anders Zetterberg
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Ran Kafri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
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18
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Huang WYC, Cheng X, Ferrell JE. Cytoplasmic organization promotes protein diffusion in Xenopus extracts. Nat Commun 2022; 13:5599. [PMID: 36151204 PMCID: PMC9508076 DOI: 10.1038/s41467-022-33339-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 09/12/2022] [Indexed: 11/25/2022] Open
Abstract
The cytoplasm is highly organized. However, the extent to which this organization influences the dynamics of cytoplasmic proteins is not well understood. Here, we use Xenopus laevis egg extracts as a model system to study diffusion dynamics in organized versus disorganized cytoplasm. Such extracts are initially homogenized and disorganized, and self-organize into cell-like units over the course of tens of minutes. Using fluorescence correlation spectroscopy, we observe that as the cytoplasm organizes, protein diffusion speeds up by about a factor of two over a length scale of a few hundred nanometers, eventually approaching the diffusion time measured in organelle-depleted cytosol. Even though the ordered cytoplasm contained organelles and cytoskeletal elements that might interfere with diffusion, the convergence of protein diffusion in the cytoplasm toward that in organelle-depleted cytosol suggests that subcellular organization maximizes protein diffusivity. The effect of organization on diffusion varies with molecular size, with the effects being largest for protein-sized molecules, and with the time scale of the measurement. These results show that cytoplasmic organization promotes the efficient diffusion of protein molecules in a densely packed environment. Cytoplasmic organization is a hallmark of living cells. Here, the authors make use of self-organizing cell extracts to examine how the emergence of large-scale organizations influences the microscopic diffusion of protein molecules in the cytoplasm.
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Affiliation(s)
- William Y C Huang
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Xianrui Cheng
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA. .,Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA. .,Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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19
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Dupin A, Aufinger L, Styazhkin I, Rothfischer F, Kaufmann BK, Schwarz S, Galensowske N, Clausen-Schaumann H, Simmel FC. Synthetic cell-based materials extract positional information from morphogen gradients. SCIENCE ADVANCES 2022; 8:eabl9228. [PMID: 35394842 PMCID: PMC8993112 DOI: 10.1126/sciadv.abl9228] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/17/2022] [Indexed: 05/19/2023]
Abstract
Biomaterials composed of synthetic cells have the potential to adapt and differentiate guided by physicochemical environmental cues. Inspired by biological systems in development, which extract positional information (PI) from morphogen gradients in the presence of uncertainties, we here investigate how well synthetic cells can determine their position within a multicellular structure. To calculate PI, we created and analyzed a large number of synthetic cellular assemblies composed of emulsion droplets connected via lipid bilayer membranes. These droplets contained cell-free feedback gene circuits that responded to gradients of a genetic inducer acting as a morphogen. PI is found to be limited by gene expression noise and affected by the temporal evolution of the morphogen gradient and the cell-free expression system itself. The generation of PI can be rationalized by computational modeling of the system. We scale our approach using three-dimensional printing and demonstrate morphogen-based differentiation in larger tissue-like assemblies.
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Affiliation(s)
- Aurore Dupin
- Physics Department (E14), TU Munich, 85748 Garching, Germany
| | - Lukas Aufinger
- Physics Department (E14), TU Munich, 85748 Garching, Germany
| | - Igor Styazhkin
- Physics Department (E14), TU Munich, 85748 Garching, Germany
| | | | - Benedikt K. Kaufmann
- Center for NanoScience (CeNS), Schellingstraße 4, 80799 Munich, Germany
- Center for Applied Tissue Engineering and Regenerative Medicine-CANTER, Munich University of Applied Sciences, Lothstrasse 34, 80335 Munich, Germany
- Heinz-Nixdorf-Chair of Biomedical Electronics, TranslaTUM, TU Munich, 81675 Munich, Germany
| | - Sascha Schwarz
- Center for NanoScience (CeNS), Schellingstraße 4, 80799 Munich, Germany
- Center for Applied Tissue Engineering and Regenerative Medicine-CANTER, Munich University of Applied Sciences, Lothstrasse 34, 80335 Munich, Germany
| | | | - Hauke Clausen-Schaumann
- Center for NanoScience (CeNS), Schellingstraße 4, 80799 Munich, Germany
- Center for Applied Tissue Engineering and Regenerative Medicine-CANTER, Munich University of Applied Sciences, Lothstrasse 34, 80335 Munich, Germany
| | - Friedrich C. Simmel
- Physics Department (E14), TU Munich, 85748 Garching, Germany
- Corresponding author.
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20
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Microtubule and Actin Cytoskeletal Dynamics in Male Meiotic Cells of Drosophila melanogaster. Cells 2022; 11:cells11040695. [PMID: 35203341 PMCID: PMC8870657 DOI: 10.3390/cells11040695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 01/12/2023] Open
Abstract
Drosophila dividing spermatocytes offer a highly suitable cell system in which to investigate the coordinated reorganization of microtubule and actin cytoskeleton systems during cell division of animal cells. Like male germ cells of mammals, Drosophila spermatogonia and spermatocytes undergo cleavage furrow ingression during cytokinesis, but abscission does not take place. Thus, clusters of primary and secondary spermatocytes undergo meiotic divisions in synchrony, resulting in cysts of 32 secondary spermatocytes and then 64 spermatids connected by specialized structures called ring canals. The meiotic spindles in Drosophila males are substantially larger than the spindles of mammalian somatic cells and exhibit prominent central spindles and contractile rings during cytokinesis. These characteristics make male meiotic cells particularly amenable to immunofluorescence and live imaging analysis of the spindle microtubules and the actomyosin apparatus during meiotic divisions. Moreover, because the spindle assembly checkpoint is not robust in spermatocytes, Drosophila male meiosis allows investigating of whether gene products required for chromosome segregation play additional roles during cytokinesis. Here, we will review how the research studies on Drosophila male meiotic cells have contributed to our knowledge of the conserved molecular pathways that regulate spindle microtubules and cytokinesis with important implications for the comprehension of cancer and other diseases.
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21
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Jin M, Tavella F, Wang S, Yang Q. In vitro cell cycle oscillations exhibit a robust and hysteretic response to changes in cytoplasmic density. Proc Natl Acad Sci U S A 2022; 119:e2109547119. [PMID: 35101974 PMCID: PMC8832984 DOI: 10.1073/pnas.2109547119] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/17/2021] [Indexed: 12/25/2022] Open
Abstract
Cells control the properties of the cytoplasm to ensure proper functioning of biochemical processes. Recent studies showed that cytoplasmic density varies in both physiological and pathological states of cells undergoing growth, division, differentiation, apoptosis, senescence, and metabolic starvation. Little is known about how cellular processes cope with these cytoplasmic variations. Here, we study how a cell cycle oscillator comprising cyclin-dependent kinase (Cdk1) responds to changes in cytoplasmic density by systematically diluting or concentrating cycling Xenopus egg extracts in cell-like microfluidic droplets. We found that the cell cycle maintains robust oscillations over a wide range of deviations from the endogenous density: as low as 0.2× to more than 1.22× relative cytoplasmic density (RCD). A further dilution or concentration from these values arrested the system in a low or high steady state of Cdk1 activity, respectively. Interestingly, diluting an arrested cytoplasm of 1.22× RCD recovers oscillations at lower than 1× RCD. Thus, the cell cycle switches reversibly between oscillatory and stable steady states at distinct thresholds depending on the direction of tuning, forming a hysteresis loop. We propose a mathematical model which recapitulates these observations and predicts that the Cdk1/Wee1/Cdc25 positive feedback loops do not contribute to the observed robustness, supported by experiments. Our system can be applied to study how cytoplasmic density affects other cellular processes.
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Affiliation(s)
- Minjun Jin
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109
| | - Franco Tavella
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109
| | - Shiyuan Wang
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109;
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109
- Department of Physics, University of Michigan, Ann Arbor, MI 48109
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22
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Ali Al-Radhawi M, Margaliot M, Sontag ED. Maximizing average throughput in oscillatory biochemical synthesis systems: an optimal control approach. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210878. [PMID: 34567591 PMCID: PMC8456142 DOI: 10.1098/rsos.210878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/16/2021] [Indexed: 05/03/2023]
Abstract
A dynamical system entrains to a periodic input if its state converges globally to an attractor with the same period. In particular, for a constant input, the state converges to a unique equilibrium point for any initial condition. We consider the problem of maximizing a weighted average of the system's output along the periodic attractor. The gain of entrainment is the benefit achieved by using a non-constant periodic input relative to a constant input with the same time average. Such a problem amounts to optimal allocation of resources in a periodic manner. We formulate this problem as a periodic optimal control problem, which can be analysed by means of the Pontryagin maximum principle or solved numerically via powerful software packages. We then apply our framework to a class of nonlinear occupancy models that appear frequently in biological synthesis systems and other applications. We show that, perhaps surprisingly, constant inputs are optimal for various architectures. This suggests that the presence of non-constant periodic signals, which frequently appear in biological occupancy systems, is a signature of an underlying time-varying objective functional being optimized.
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Affiliation(s)
- M. Ali Al-Radhawi
- Departments of Bioengineering and Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA
| | - Michael Margaliot
- Department of Electrical Engineering-Systems, Tel Aviv University, Tel Aviv, Israel 69978
| | - Eduardo D. Sontag
- Departments of Bioengineering and Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA
- Laboratory of Systems Pharmacology, Program in Therapeutic Science, Harvard Medical School, Boston, MA 02115, USA
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23
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Gai Y, Cook B, Setru S, Stone HA, Petry S. Confinement size determines the architecture of Ran-induced microtubule networks. SOFT MATTER 2021; 17:5921-5931. [PMID: 34041514 PMCID: PMC8958645 DOI: 10.1039/d1sm00045d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The organization of microtubules (MTs) is critical for cells during interphase and mitosis. During mitotic spindle assembly, MTs are made and organized around chromosomes in a process regulated by RanGTP. The role of RanGTP has been explored in Xenopus egg extracts, which are not limited by a cell membrane. Here, we investigated whether cell-sized confinements affect the assembly of RanGTP-induced MT networks in Xenopus egg extracts. We used microfluidics to encapsulate extracts within monodisperse extract-in-oil droplets. Importantly, we find that the architecture of Ran-induced MT networks depends on the droplet diameter and the Ran concentration, and differs from structures formed in bulk extracts. Our results highlight that both MT nucleation and physical confinement play critical roles in determining the spatial organization of the MT cytoskeleton.
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Affiliation(s)
- Ya Gai
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Brian Cook
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
| | - Sagar Setru
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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24
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Sun M, Maryu G, Wang S, Yang Q, Bailey RC. Plug-in tubes allow tunable oil removal, droplet packing, and reaction incubation for time-controlled droplet-based assays. BIOMICROFLUIDICS 2021; 15:024108. [PMID: 33841602 PMCID: PMC8024030 DOI: 10.1063/5.0047924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 03/20/2021] [Indexed: 06/12/2023]
Abstract
Here, we report a unique microfluidic technique that utilizes a membrane filter and plug-in tubes to remove oil and pack water-in-oil droplets for controlled incubation of droplet-based assays. This technique could be modularly incorporated into most droplet-generation devices without a need to alter the original designs. Our results show that removing excess oil to form tightly packed droplets allows for extended and controllable incubation for droplets traveling in microchannels. The efficiency of this technique was evaluated and confirmed using a time-dependent enzyme assay with a fluorometric readout. The system is also readily generalizable to control inter-droplet distance, crucial for studying droplet communication and pattern formation.
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Affiliation(s)
| | - Gembu Maryu
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Shiyuan Wang
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ryan C. Bailey
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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25
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Xiao Y, Jin L, Deng C, Guan Y, Kalogera E, Ray U, Thirusangu P, Staub J, Sarkar Bhattacharya S, Xu H, Fang X, Shridhar V. Inhibition of PFKFB3 induces cell death and synergistically enhances chemosensitivity in endometrial cancer. Oncogene 2021; 40:1409-1424. [PMID: 33420377 PMCID: PMC7906909 DOI: 10.1038/s41388-020-01621-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 12/05/2020] [Accepted: 12/11/2020] [Indexed: 02/07/2023]
Abstract
The advanced or recurrent endometrial cancer (EC) has a poor prognosis because of chemoresistance. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a glycolytic enzyme, is overexpressed in a variety of human cancers and plays important roles in promoting tumor cell growth. Here, we showed that high expression of PFKFB3 in EC cell lines is associated with chemoresistance. Pharmacological inhibition of PFKFB3 with PFK158 and or genetic downregulation of PFKFB3 dramatically suppressed cell proliferation and enhanced the sensitivity of EC cells to carboplatin (CBPt) and cisplatin (Cis). Moreover, PFKFB3 inhibition resulted in reduced glucose uptake, ATP production, and lactate release. Notably, we found that PFK158 with CBPt or Cis exerted strong synergistic antitumor activity in chemoresistant EC cell lines, HEC-1B and ARK-2 cells. We also found that the combination of PFK158 and CBPt/Cis induced apoptosis- and autophagy-mediated cell death through inhibition of the Akt/mTOR signaling pathway. Mechanistically, we found that PFK158 downregulated the CBPt/Cis-induced upregulation of RAD51 expression and enhanced CBPt/Cis-induced DNA damage as demonstrated by an increase in γ-H2AX levels in HEC-1B and ARK-2 cells, potentially revealing a means to enhance PFK158-induced chemosensitivity. More importantly, PFK158 treatment, either as monotherapy or in combination with CBPt, led to a marked reduction in tumor growth in two chemoresistant EC mouse xenograft models. These data suggest that PFKFB3 inhibition alone or in combination with standard chemotherapy may be used as a novel therapeutic strategy for improved therapeutic efficacy and outcomes of advanced and recurrent EC patients.
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Affiliation(s)
- Yinan Xiao
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA ,grid.452708.c0000 0004 1803 0208Department of Obstetrics and Gynecology, the Second Xiangya Hospital, Central South University, Changsha, Hunan P.R. China
| | - Ling Jin
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA
| | - Chaolin Deng
- grid.66875.3a0000 0004 0459 167XDepartment of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN USA
| | - Ye Guan
- grid.214458.e0000000086837370Department of Chemistry, University of Michigan, Ann Arbor, MI USA
| | - Eleftheria Kalogera
- grid.66875.3a0000 0004 0459 167XDivision of Gynecologic Oncology, Mayo Clinic, Rochester, MN USA
| | - Upasana Ray
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA
| | - Prabhu Thirusangu
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA
| | - Julie Staub
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA
| | | | - Haotian Xu
- grid.254444.70000 0001 1456 7807Department of Computer Science, Wayne State University, Detroit, MI USA
| | - Xiaoling Fang
- grid.452708.c0000 0004 1803 0208Department of Obstetrics and Gynecology, the Second Xiangya Hospital, Central South University, Changsha, Hunan P.R. China
| | - Viji Shridhar
- grid.66875.3a0000 0004 0459 167XDepartment of Experimental Pathology, Mayo Clinic, Rochester, MN USA
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26
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Groaz A, Moghimianavval H, Tavella F, Giessen TW, Vecchiarelli AG, Yang Q, Liu AP. Engineering spatiotemporal organization and dynamics in synthetic cells. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2020; 13:e1685. [PMID: 33219745 DOI: 10.1002/wnan.1685] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/13/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022]
Abstract
Constructing synthetic cells has recently become an appealing area of research. Decades of research in biochemistry and cell biology have amassed detailed part lists of components involved in various cellular processes. Nevertheless, recreating any cellular process in vitro in cell-sized compartments remains ambitious and challenging. Two broad features or principles are key to the development of synthetic cells-compartmentalization and self-organization/spatiotemporal dynamics. In this review article, we discuss the current state of the art and research trends in the engineering of synthetic cell membranes, development of internal compartmentalization, reconstitution of self-organizing dynamics, and integration of activities across scales of space and time. We also identify some research areas that could play a major role in advancing the impact and utility of engineered synthetic cells. This article is categorized under: Biology-Inspired Nanomaterials > Lipid-Based Structures Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.
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Affiliation(s)
| | | | | | | | | | - Qiong Yang
- University of Michigan, Ann Arbor, Michigan, USA
| | - Allen P Liu
- University of Michigan, Ann Arbor, Michigan, USA
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27
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Cho E, Lu Y. Compartmentalizing Cell-Free Systems: Toward Creating Life-Like Artificial Cells and Beyond. ACS Synth Biol 2020; 9:2881-2901. [PMID: 33095011 DOI: 10.1021/acssynbio.0c00433] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Building an artificial cell is a research area that is rigorously studied in the field of synthetic biology. It has brought about much attention with the aim of ultimately constructing a natural cell-like structure. In particular, with the more mature cell-free platforms and various compartmentalization methods becoming available, achieving this aim seems not far away. In this review, we discuss the various types of artificial cells capable of hosting several cellular functions. Different compartmental boundaries and the mature and evolving technologies that are used for compartmentalization are examined, and exciting recent advances that overcome or have the potential to address current challenges are discussed. Ultimately, we show how compartmentalization and cell-free systems have, and will, come together to fulfill the goal to assemble a fully synthetic cell that displays functionality and complexity as advanced as that in nature. The development of such artificial cell systems will offer insight into the fundamental study of evolutionary biology and the sea of applications as a result. Although several challenges remain, emerging technologies such as artificial intelligence also appear to help pave the way to address them and achieve the ultimate goal.
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Affiliation(s)
- Eunhee Cho
- Key Lab of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Yuan Lu
- Key Lab of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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28
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Abstract
The cell-free molecular synthesis of biochemical systems is a rapidly growing field of research. Advances in the Human Genome Project, DNA synthesis, and other technologies have allowed the in vitro construction of biochemical systems, termed cell-free biology, to emerge as an exciting domain of bioengineering. Cell-free biology ranges from the molecular to the cell-population scales, using an ever-expanding variety of experimental platforms and toolboxes. In this review, we discuss the ongoing efforts undertaken in the three major classes of cell-free biology methodologies, namely protein-based, nucleic acids–based, and cell-free transcription–translation systems, and provide our perspectives on the current challenges as well as the major goals in each of the subfields.
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Affiliation(s)
- Vincent Noireaux
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Allen P. Liu
- Departments of Mechanical Engineering, Biomedical Engineering, Biophysics, and the Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109, USA
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29
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Nolet FE, Vandervelde A, Vanderbeke A, Piñeros L, Chang JB, Gelens L. Nuclei determine the spatial origin of mitotic waves. eLife 2020; 9:e52868. [PMID: 32452767 PMCID: PMC7314552 DOI: 10.7554/elife.52868] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/22/2020] [Indexed: 12/11/2022] Open
Abstract
Traveling waves play an essential role in coordinating mitosis over large distances, but what determines the spatial origin of mitotic waves remains unclear. Here, we show that such waves initiate at pacemakers, regions that oscillate faster than their surroundings. In cell-free extracts of Xenopus laevis eggs, we find that nuclei define such pacemakers by concentrating cell cycle regulators. In computational models of diffusively coupled oscillators that account for nuclear import, nuclear positioning determines the pacemaker location. Furthermore, we find that the spatial dimensions of the oscillatory medium change the nuclear positioning and strongly influence whether a pacemaker is more likely to be at a boundary or an internal region. Finally, we confirm experimentally that increasing the system width increases the proportion of pacemakers at the boundary. Our work provides insight into how nuclei and spatial system dimensions can control local concentrations of regulators and influence the emergent behavior of mitotic waves.
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Affiliation(s)
- Felix E Nolet
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU LeuvenLeuvenBelgium
| | - Alexandra Vandervelde
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU LeuvenLeuvenBelgium
| | - Arno Vanderbeke
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU LeuvenLeuvenBelgium
- MeBioS - Biosensors Group, Department of Biosystems, KU LeuvenLeuvenBelgium
| | - Liliana Piñeros
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU LeuvenLeuvenBelgium
| | - Jeremy B Chang
- Department of Pharmaceutical ChemistryUniversity of California, San FranciscoUnited States
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU LeuvenLeuvenBelgium
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30
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Prangemeier T, Lehr FX, Schoeman RM, Koeppl H. Microfluidic platforms for the dynamic characterisation of synthetic circuitry. Curr Opin Biotechnol 2020; 63:167-176. [PMID: 32172160 DOI: 10.1016/j.copbio.2020.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 01/28/2023]
Abstract
Generating novel functionality from well characterised synthetic parts and modules lies at the heart of synthetic biology. Ideally, circuitry is rationally designed in silico with quantitatively predictive models to predetermined design specifications. Synthetic circuits are intrinsically stochastic, often dynamically modulated and set in a dynamic fluctuating environment within a living cell. To build more complex circuits and to gain insight into context effects, intrinsic noise and transient performance, characterisation techniques that resolve both heterogeneity and dynamics are required. Here we review recent advances in both in vitro and in vivo microfluidic technologies that are suitable for the characterisation of synthetic circuitry, modules and parts.
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Affiliation(s)
- Tim Prangemeier
- Centre for Synthetic Biology, Department of Electrical Engineering and Information Technology, Department of Biology, Technische Universität Darmstadt, Germany
| | - François-Xavier Lehr
- Centre for Synthetic Biology, Department of Electrical Engineering and Information Technology, Department of Biology, Technische Universität Darmstadt, Germany
| | - Rogier M Schoeman
- Centre for Synthetic Biology, Department of Electrical Engineering and Information Technology, Department of Biology, Technische Universität Darmstadt, Germany
| | - Heinz Koeppl
- Centre for Synthetic Biology, Department of Electrical Engineering and Information Technology, Department of Biology, Technische Universität Darmstadt, Germany.
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31
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Wesley CC, Mishra S, Levy DL. Organelle size scaling over embryonic development. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e376. [PMID: 32003549 DOI: 10.1002/wdev.376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/19/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Cell division without growth results in progressive cell size reductions during early embryonic development. How do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? Model organisms, in particular Caenorhabditis elegans worms, Drosophila melanogaster flies, Xenopus laevis frogs, and Mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosomes. Nuclear size is regulated by nucleocytoplasmic transport, nuclear envelope proteins, and the cytoskeleton. Regulators of microtubule dynamics and chromatin compaction modulate spindle and mitotic chromosome size scaling, respectively. Developmental scaling relationships for membrane-bound organelles, like the endoplasmic reticulum, Golgi, mitochondria, and lysosomes, have been less studied, although new imaging approaches promise to rectify this deficiency. While models that invoke limiting components and dynamic regulation of assembly and disassembly can account for some size scaling relationships in early embryos, it will be exciting to investigate the contribution of newer concepts in cell biology such as phase separation and interorganellar contacts. With a growing understanding of the underlying mechanisms of organelle size scaling, future studies promise to uncover the significance of proper scaling for cell function and embryonic development, as well as how aberrant scaling contributes to disease. This article is categorized under: Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Early Embryonic Development > Fertilization to Gastrulation Comparative Development and Evolution > Model Systems.
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Affiliation(s)
- Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
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32
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Affiliation(s)
- Timothy J. Mitchison
- Harvard Medical School, Boston, MA, USA
- Marine Biological Laboratory, Woods Hole, MA, USA
| | - Christine M. Field
- Harvard Medical School, Boston, MA, USA
- Marine Biological Laboratory, Woods Hole, MA, USA
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33
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Sun M, Li Z, Wang S, Maryu G, Yang Q. Building Dynamic Cellular Machineries in Droplet-Based Artificial Cells with Single-Droplet Tracking and Analysis. Anal Chem 2019; 91:9813-9818. [PMID: 31284720 PMCID: PMC7260773 DOI: 10.1021/acs.analchem.9b01481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although the application of droplet microfluidics has grown exponentially in chemistry and biology over the past decades, robust universal platforms for the routine generation and comprehensive analysis of droplet-based artificial cells are still rare. Here we report using microfluidic droplets to reproduce a variety of types of cellular machinery in in vitro artificial cells. In combination with a unique image-based analysis method, the system enables full automation in tracking single droplets with high accuracy, high throughput, and high sensitivity. These powerful performances allow broad applicability evident in three representative droplet-based analytical prototypes that we develop for (i) droplet digital detection, (ii) in vitro transcription and translation reactions, and (iii) spatiotemporal dynamics of cell-cycle oscillations. The capacities of this platform to generate, incubate, track, and analyze individual microdroplets via real-time, long-term imaging unleash its great potential in accelerating cell-free synthetic biology. Moreover, the wide scope covering from digital to analog to morphological detections makes this droplet analysis technique adaptable for many other divergent types of droplet-based chemical and biological assays.
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Affiliation(s)
- Meng Sun
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhengda Li
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Shiyuan Wang
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Gembu Maryu
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Qiong Yang
- Department of Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, Michigan 48109, United States
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34
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Sun M, Li Z, Yang Q. μdroPi: A Hand-Held Microfluidic Droplet Imager and Analyzer Built on Raspberry Pi. JOURNAL OF CHEMICAL EDUCATION 2019; 96:1152-1156. [PMID: 32483390 PMCID: PMC7263740 DOI: 10.1021/acs.jchemed.8b00975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We built a low-cost and hand-held device to image and analyze microfluidic droplets mainly for educational/teaching purposes in laboratory settings of universities. The device was assembled based on a Raspberry Pi with a camera attached on the back and an LCD screen on the top. We evaluated the performance of this device to capture images and videos to visualize high-throughput droplet generation in a microfluidic device. The qualities of imaging resolution and speed were sufficient for us to perform subsequent droplet analysis quantitatively through automatic image possessing. Droplet characteristics including droplet size, volume, and dispersity, as well as droplet intensity, have been measured, showing the potential of this device to analyze droplet-based assays. Most importantly, in addition to learning the knowledge and principles from classroom lectures, students can thus gain practice of using an advanced, state-of-the-art technology in a laboratory course. It will also open up opportunities to train students with skills of interdisciplinary thinking and learning.
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Affiliation(s)
- Meng Sun
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhengda Li
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
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35
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Dubuc E, Pieters PA, van der Linden AJ, van Hest JC, Huck WT, de Greef TF. Cell-free microcompartmentalised transcription-translation for the prototyping of synthetic communication networks. Curr Opin Biotechnol 2018; 58:72-80. [PMID: 30594098 PMCID: PMC6723619 DOI: 10.1016/j.copbio.2018.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 10/14/2018] [Indexed: 12/21/2022]
Abstract
Recent efforts in synthetic biology have shown the possibility of engineering distributed functions in populations of living cells, which requires the development of highly orthogonal, genetically encoded communication pathways. Cell-free transcription-translation (TXTL) reactions encapsulated in microcompartments enable prototyping of molecular communication channels and their integration into engineered genetic circuits by mimicking critical cell features, such as gene expression, cell size, and cell individuality within a community. In this review, we discuss the uses of cell-free transcription-translation reactions for the development of synthetic genetic circuits, with a special focus on the use of microcompartments supporting this reaction. We highlight several studies where molecular communication between non-living microcompartments and living cells have been successfully engineered.
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Affiliation(s)
- Emilien Dubuc
- Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Pascal A Pieters
- Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Ardjan J van der Linden
- Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Jan Cm van Hest
- Department of Biomedical Engineering & Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Wilhelm Ts Huck
- Department of Physical Organic Chemistry, Institute for Molecules and Materials, Radboud University, Nijmegen 6525 HP, The Netherlands
| | - Tom Fa de Greef
- Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Computational Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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36
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Guan Y, Wang S, Jin M, Xu H, Yang Q. Reconstitution of Cell-cycle Oscillations in Microemulsions of Cell-free Xenopus Egg Extracts. J Vis Exp 2018:58240. [PMID: 30320763 PMCID: PMC6235322 DOI: 10.3791/58240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Real-time measurement of oscillations at the single-cell level is important to uncover the mechanisms of biological clocks. Although bulk extracts prepared from Xenopus laevis eggs have been powerful in dissecting biochemical networks underlying the cell-cycle progression, their ensemble average measurement typically leads to a damped oscillation, despite each individual oscillator being sustained. This is due to the difficulty of perfect synchronization among individual oscillators in noisy biological systems. To retrieve the single-cell dynamics of the oscillator, we developed a droplet-based artificial cell system that can reconstitute mitotic cycles in cell-like compartments encapsulating cycling cytoplasmic extracts of Xenopus laevis eggs. These simple cytoplasmic-only cells exhibit sustained oscillations for over 30 cycles. To build more complicated cells with nuclei, we added demembranated sperm chromatin to trigger nuclei self-assembly in the system. We observed a periodic progression of chromosome condensation/decondensation and nuclei envelop breakdown/reformation, like in real cells. This indicates that the mitotic oscillator functions faithfully to drive multiple downstream mitotic events. We simultaneously tracked the dynamics of the mitotic oscillator and downstream processes in individual droplets using multi-channel time-lapse fluorescence microscopy. The artificial cell-cycle system provides a high-throughput framework for quantitative manipulation and analysis of mitotic oscillations with single-cell resolution, which likely provides important insights into the regulatory machinery and functions of the clock.
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Affiliation(s)
- Ye Guan
- Department of Biophysics, University of Michigan, Ann Arbor; Department of Chemistry, University of Michigan, Ann Arbor
| | - Shiyuan Wang
- Department of Biophysics, University of Michigan, Ann Arbor
| | - Minjun Jin
- Department of Chemistry, University of Michigan, Ann Arbor
| | - Haotian Xu
- Department of Computer Science, Wayne State University
| | - Qiong Yang
- Department of Biophysics, University of Michigan, Ann Arbor; Department of Physics, University of Michigan, Ann Arbor;
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