1
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Mori M, Koshiguchi M, Takenouchi O, Mukose MA, Takase HM, Mishina T, Mei H, Kihara M, Abe T, Inoue A, Kitajima TS. Aging-associated reduction of chromosomal histones in mammalian oocytes. Genes Cells 2024. [PMID: 39044347 DOI: 10.1111/gtc.13146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 07/14/2024] [Accepted: 07/14/2024] [Indexed: 07/25/2024]
Abstract
Mammalian oocytes undergo a long-term meiotic arrest that can last for almost the entire reproductive lifespan. This arrest occurs after DNA replication and is prolonged with age, which poses a challenge to oocytes in maintaining replication-dependent chromosomal proteins required for the completion of meiosis. In this study, we show that chromosomal histones are reduced with age in mouse oocytes. Both types of histone H3 variants, replication-dependent H3.1/H3.2 and replication-independent H3.3, decrease with age. Aging-associated histone reduction is associated with transcriptomic features that are caused by genetic depletion of histone H3.3. Neither the genetic reduction of chromosomal H3.1/H3.2 nor H3.3 accelerates the aging-associated increase in premature chromosome separation that causes meiotic segregation errors. We suggest that aging-associated reduction of chromosomal histones is linked to several transcriptomic abnormalities but does not significantly contribute to errors in meiotic chromosome segregation during the reproductive lifespan of mice.
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Affiliation(s)
- Masashi Mori
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Manami Koshiguchi
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Osamu Takenouchi
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Mei A Mukose
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hinako M Takase
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Tappei Mishina
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Hailiang Mei
- Laboratory for Epigenome Inheritance, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Miho Kihara
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Azusa Inoue
- Laboratory for Epigenome Inheritance, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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2
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Takenouchi O, Sakakibara Y, Kitajima TS. Live chromosome identifying and tracking reveals size-based spatial pathway of meiotic errors in oocytes. Science 2024; 385:eadn5529. [PMID: 39024439 DOI: 10.1126/science.adn5529] [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: 12/15/2023] [Accepted: 05/24/2024] [Indexed: 07/20/2024]
Abstract
Meiotic errors of relatively small chromosomes in oocytes result in egg aneuploidies that cause miscarriages and congenital diseases. Unlike somatic cells, which preferentially mis-segregate larger chromosomes, aged oocytes preferentially mis-segregate smaller chromosomes through unclear processes. Here, we provide a comprehensive three-dimensional chromosome identifying-and-tracking dataset throughout meiosis I in live mouse oocytes. This analysis reveals a prometaphase pathway that actively moves smaller chromosomes to the inner region of the metaphase plate. In the inner region, chromosomes are pulled by stronger bipolar microtubule forces, which facilitates premature chromosome separation, a major cause of segregation errors in aged oocytes. This study reveals a spatial pathway that facilitates aneuploidy of small chromosomes preferentially in aged eggs and implicates the role of the M phase in creating a chromosome size-based spatial arrangement.
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Affiliation(s)
- Osamu Takenouchi
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Yogo Sakakibara
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
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3
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Rana U, Xu K, Narayanan A, Walls MT, Panagiotopoulos AZ, Avalos JL, Brangwynne CP. Asymmetric oligomerization state and sequence patterning can tune multiphase condensate miscibility. Nat Chem 2024; 16:1073-1082. [PMID: 38383656 PMCID: PMC11230906 DOI: 10.1038/s41557-024-01456-6] [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: 03/10/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024]
Abstract
Endogenous biomolecular condensates, composed of a multitude of proteins and RNAs, can organize into multiphasic structures with compositionally distinct phases. This multiphasic organization is generally understood to be critical for facilitating their proper biological function. However, the biophysical principles driving multiphase formation are not completely understood. Here we use in vivo condensate reconstitution experiments and coarse-grained molecular simulations to investigate how oligomerization and sequence interactions modulate multiphase organization in biomolecular condensates. We demonstrate that increasing the oligomerization state of an intrinsically disordered protein results in enhanced immiscibility and multiphase formation. Interestingly, we find that oligomerization tunes the miscibility of intrinsically disordered proteins in an asymmetric manner, with the effect being more pronounced when the intrinsically disordered protein, exhibiting stronger homotypic interactions, is oligomerized. Our findings suggest that oligomerization is a flexible biophysical mechanism that cells can exploit to tune the internal organization of biomolecular condensates and their associated biological functions.
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Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Ke Xu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Amal Narayanan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA
| | - Mackenzie T Walls
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - José L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
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4
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Fung HKH, Hayashi Y, Salo VT, Babenko A, Zagoriy I, Brunner A, Ellenberg J, Müller CW, Cuylen-Haering S, Mahamid J. Genetically encoded multimeric tags for subcellular protein localization in cryo-EM. Nat Methods 2023; 20:1900-1908. [PMID: 37932397 PMCID: PMC10703698 DOI: 10.1038/s41592-023-02053-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 09/19/2023] [Indexed: 11/08/2023]
Abstract
Cryo-electron tomography (cryo-ET) allows for label-free high-resolution imaging of macromolecular assemblies in their native cellular context. However, the localization of macromolecules of interest in tomographic volumes can be challenging. Here we present a ligand-inducible labeling strategy for intracellular proteins based on fluorescent, 25-nm-sized, genetically encoded multimeric particles (GEMs). The particles exhibit recognizable structural signatures, enabling their automated detection in cryo-ET data by convolutional neural networks. The coupling of GEMs to green fluorescent protein-tagged macromolecules of interest is triggered by addition of a small-molecule ligand, allowing for time-controlled labeling to minimize disturbance to native protein function. We demonstrate the applicability of GEMs for subcellular-level localization of endogenous and overexpressed proteins across different organelles in human cells using cryo-correlative fluorescence and cryo-ET imaging. We describe means for quantifying labeling specificity and efficiency, and for systematic optimization for rare and abundant protein targets, with emphasis on assessing the potential effects of labeling on protein function.
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Affiliation(s)
- Herman K H Fung
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yuki Hayashi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Anastasiia Babenko
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andreas Brunner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Faculty of Biosciences, Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Sara Cuylen-Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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5
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Collombet S, Rall I, Dugast-Darzacq C, Heckert A, Halavatyi A, Le Saux A, Dailey G, Darzacq X, Heard E. RNA polymerase II depletion from the inactive X chromosome territory is not mediated by physical compartmentalization. Nat Struct Mol Biol 2023; 30:1216-1223. [PMID: 37291424 PMCID: PMC10442225 DOI: 10.1038/s41594-023-01008-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/28/2023] [Indexed: 06/10/2023]
Abstract
Subnuclear compartmentalization has been proposed to play an important role in gene regulation by segregating active and inactive parts of the genome in distinct physical and biochemical environments. During X chromosome inactivation (XCI), the noncoding Xist RNA coats the X chromosome, triggers gene silencing and forms a dense body of heterochromatin from which the transcription machinery appears to be excluded. Phase separation has been proposed to be involved in XCI, and might explain the exclusion of the transcription machinery by preventing its diffusion into the Xist-coated territory. Here, using quantitative fluorescence microscopy and single-particle tracking, we show that RNA polymerase II (RNAPII) freely accesses the Xist territory during the initiation of XCI. Instead, the apparent depletion of RNAPII is due to the loss of its chromatin stably bound fraction. These findings indicate that initial exclusion of RNAPII from the inactive X reflects the absence of actively transcribing RNAPII, rather than a consequence of putative physical compartmentalization of the inactive X heterochromatin domain.
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Affiliation(s)
| | - Isabell Rall
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Claire Dugast-Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Alec Heckert
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA, USA
| | | | - Agnes Le Saux
- Curie Institute, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, Paris, France
| | - Gina Dailey
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA, USA.
| | - Edith Heard
- European Molecular Biology Laboratory, Heidelberg, Germany.
- Curie Institute, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, Paris, France.
- College de France, Paris, France.
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6
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Actin-driven chromosome clustering facilitates fast and complete chromosome capture in mammalian oocytes. Nat Cell Biol 2023; 25:439-452. [PMID: 36732633 PMCID: PMC10014578 DOI: 10.1038/s41556-022-01082-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/20/2022] [Indexed: 02/04/2023]
Abstract
Accurate chromosome segregation during meiosis is crucial for reproduction. Human and porcine oocytes transiently cluster their chromosomes before the onset of spindle assembly and subsequent chromosome segregation. The mechanism and function of chromosome clustering are unknown. Here we show that chromosome clustering is required to prevent chromosome losses in the long gap phase between nuclear envelope breakdown and the onset of spindle assembly, and to promote the rapid capture of all chromosomes by the acentrosomal spindle. The initial phase of chromosome clustering is driven by a dynamic network of Formin-2- and Spire-nucleated actin cables. The actin cables form in the disassembling nucleus and migrate towards the nuclear centre, moving the chromosomes centripetally by interacting with their arms and kinetochores as they migrate. A cage of stable microtubule loops drives the late stages of chromosome clustering. Together, our data establish a crucial role for chromosome clustering in accurate progression through meiosis.
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7
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Hedlund H, Du Rietz H, Johansson JM, Eriksson HC, Zedan W, Huang L, Wallin J, Wittrup A. Single-cell quantification and dose-response of cytosolic siRNA delivery. Nat Commun 2023; 14:1075. [PMID: 36841822 PMCID: PMC9968291 DOI: 10.1038/s41467-023-36752-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/16/2023] [Indexed: 02/27/2023] Open
Abstract
Endosomal escape and subsequent cytosolic delivery of small interfering RNA (siRNA) therapeutics is believed to be highly inefficient. Since it has not been possible to quantify cytosolic amounts of delivered siRNA at therapeutic doses, determining delivery bottlenecks and total efficiency has been difficult. Here, we present a confocal microscopy-based method to quantify cytosolic delivery of fluorescently labeled siRNA during lipid-mediated delivery. This method enables detection and quantification of sub-nanomolar cytosolic siRNA release amounts from individual release events with measures of quantitation confidence for each event. Single-cell kinetics of siRNA-mediated knockdown in cells expressing destabilized eGFP unveiled a dose-response relationship with respect to knockdown induction, depth and duration in the range from several hundred to thousands of cytosolic siRNA molecules. Accurate quantification of cytosolic siRNA, and the establishment of the intracellular dose-response relationships, will aid the development and characterization of novel delivery strategies for nucleic acid therapeutics.
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Affiliation(s)
- Hampus Hedlund
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Hampus Du Rietz
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Johanna M Johansson
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Hanna C Eriksson
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Wahed Zedan
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Linfeng Huang
- Wang-Cai Biochemistry Lab, Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Jonas Wallin
- Department of Mathematical Statistics, Lund University, Lund, Sweden
| | - Anders Wittrup
- Department of Clinical Sciences Lund, Oncology, Faculty of Medicine, Lund University, Lund, Sweden. .,Skane University Hospital, Oncology, Lund, Sweden. .,Wallenberg Center for Molecular Medicine, Lund, Sweden.
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8
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Otsuka S, Tempkin JOB, Zhang W, Politi AZ, Rybina A, Hossain MJ, Kueblbeck M, Callegari A, Koch B, Morero NR, Sali A, Ellenberg J. A quantitative map of nuclear pore assembly reveals two distinct mechanisms. Nature 2023; 613:575-581. [PMID: 36599981 PMCID: PMC9849139 DOI: 10.1038/s41586-022-05528-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 11/04/2022] [Indexed: 01/05/2023]
Abstract
Understanding how the nuclear pore complex (NPC) is assembled is of fundamental importance to grasp the mechanisms behind its essential function and understand its role during the evolution of eukaryotes1-4. There are at least two NPC assembly pathways-one during the exit from mitosis and one during nuclear growth in interphase-but we currently lack a quantitative map of these events. Here we use fluorescence correlation spectroscopy calibrated live imaging of endogenously fluorescently tagged nucleoporins to map the changes in the composition and stoichiometry of seven major modules of the human NPC during its assembly in single dividing cells. This systematic quantitative map reveals that the two assembly pathways have distinct molecular mechanisms, in which the order of addition of two large structural components, the central ring complex and nuclear filaments are inverted. The dynamic stoichiometry data was integrated to create a spatiotemporal model of the NPC assembly pathway and predict the structures of postmitotic NPC assembly intermediates.
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Affiliation(s)
- Shotaro Otsuka
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Max Perutz Labs, University of Vienna and the Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Jeremy O B Tempkin
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Wanlu Zhang
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Z Politi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Arina Rybina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - M Julius Hossain
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Centre for Cancer Immunology, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Moritz Kueblbeck
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andrea Callegari
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Birgit Koch
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Natalia Rosalia Morero
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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9
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Sanchez PGL, Mochulska V, Mauffette Denis C, Mönke G, Tomita T, Tsuchida-Straeten N, Petersen Y, Sonnen K, François P, Aulehla A. Arnold tongue entrainment reveals dynamical principles of the embryonic segmentation clock. eLife 2022; 11:79575. [PMID: 36223168 PMCID: PMC9560162 DOI: 10.7554/elife.79575] [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] [Received: 04/19/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
Living systems exhibit an unmatched complexity, due to countless, entangled interactions across scales. Here, we aim to understand a complex system, that is, segmentation timing in mouse embryos, without a reference to these detailed interactions. To this end, we develop a coarse-grained approach, in which theory guides the experimental identification of the segmentation clock entrainment responses. We demonstrate period- and phase-locking of the segmentation clock across a wide range of entrainment parameters, including higher-order coupling. These quantifications allow to derive the phase response curve (PRC) and Arnold tongues of the segmentation clock, revealing its essential dynamical properties. Our results indicate that the somite segmentation clock has characteristics reminiscent of a highly non-linear oscillator close to an infinite period bifurcation and suggests the presence of long-term feedbacks. Combined, this coarse-grained theoretical-experimental approach reveals how we can derive simple, essential features of a highly complex dynamical system, providing precise experimental control over the pace and rhythm of the somite segmentation clock.
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Affiliation(s)
| | | | | | - Gregor Mönke
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit
| | - Takehito Tomita
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit
| | | | - Yvonne Petersen
- European Molecular Biology Laboratory (EMBL), Transgenic Service
| | - Katharina Sonnen
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit
| | | | - Alexander Aulehla
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit
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10
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Monitoring cell membrane recycling dynamics of proteins using whole-cell fluorescence recovery after photobleaching of pH-sensitive genetic tags. Nat Protoc 2022; 17:3056-3079. [PMID: 36064755 DOI: 10.1038/s41596-022-00732-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 06/07/2022] [Indexed: 11/08/2022]
Abstract
Population behavior of signaling molecules on the cell surface is key to their adaptive function. Live imaging of proteins tagged with fluorescent molecules has been an essential tool in understanding this behavior. Typically, genetic or chemical tags are used to target molecules present throughout the cell, whereas antibody-based tags label the externally exposed molecular domains only. Both approaches could potentially overlook the intricate process of in-out membrane recycling in which target molecules appear or disappear on the cell surface. This limitation is overcome by using a pH-sensitive fluorescent tag, such as Super-Ecliptic pHluorin (SEP), because its emission depends on whether it resides inside or outside the cell. Here we focus on the main glial glutamate transporter GLT1 and describe a genetic design that equips GLT1 molecules with SEP without interfering with the transporter's main function. Expressing GLT1-SEP in astroglia in cultures or in hippocampal slices enables monitoring of the real-time dynamics of the cell-surface and cytosolic fractions of the transporter in living cells. Whole-cell fluorescence recovery after photobleaching and quantitative image-kinetic analysis of the resulting time-lapse images enables assessment of the rate of GLT1-SEP recycling on the cell surface, a fundamental trafficking parameter unattainable previously. The present protocol takes 15-20 d to set up cell preparations, and 2-3 d to carry out live cell experiments and data analyses. The protocol can be adapted to study different membrane molecules of interest, particularly those proteins whose lifetime on the cell surface is critical to their adaptive function.
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11
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Ogonuki N, Kyogoku H, Hino T, Osawa Y, Fujiwara Y, Inoue K, Kunieda T, Mizuno S, Tateno H, Sugiyama F, Kitajima TS, Ogura A. Birth of mice from meiotically arrested spermatocytes following biparental meiosis in halved oocytes. EMBO Rep 2022; 23:e54992. [DOI: 10.15252/embr.202254992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/01/2022] [Accepted: 04/19/2022] [Indexed: 01/05/2023] Open
Affiliation(s)
- Narumi Ogonuki
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
| | - Hirohisa Kyogoku
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research Kobe Japan
- Graduate School of Agricultural Science Kobe University Kobe Japan
| | - Toshiaki Hino
- Department of Biological Sciences Asahikawa Medical University Asahikawa Japan
| | - Yuki Osawa
- Graduate School of Comprehensive Human Sciences University of Tsukuba Tsukuba Japan
| | - Yasuhiro Fujiwara
- Laboratory of Pathology and Development Institute for Quantitative Biosciences The University of Tokyo Tokyo Japan
| | - Kimiko Inoue
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
- Graduate School of Life and Environmental Sciences University of Tsukuba Tsukuba Japan
| | - Tetsuo Kunieda
- Faculty of Veterinary Medicine Okayama University of Science Imabari Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center and Trans‐border Medical Research Center Faculty of Medicine University of Tsukuba Tsukuba Japan
| | - Hiroyuki Tateno
- Department of Biological Sciences Asahikawa Medical University Asahikawa Japan
| | - Fumihiro Sugiyama
- Laboratory Animal Resource Center and Trans‐border Medical Research Center Faculty of Medicine University of Tsukuba Tsukuba Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Atsuo Ogura
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
- Graduate School of Life and Environmental Sciences University of Tsukuba Tsukuba Japan
- RIKEN Cluster for Pioneering Research Wako Japan
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12
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Sánchez-Iranzo H, Halavatyi A, Diz-Muñoz A. Strength of interactions in the Notch gene regulatory network determines patterning and fate in the notochord. eLife 2022; 11:75429. [PMID: 35658971 PMCID: PMC9170247 DOI: 10.7554/elife.75429] [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: 11/11/2021] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Development of multicellular organisms requires the generation of gene expression patterns that determines cell fate and organ shape. Groups of genetic interactions known as Gene Regulatory Networks (GRNs) play a key role in the generation of such patterns. However, how the topology and parameters of GRNs determine patterning in vivo remains unclear due to the complexity of most experimental systems. To address this, we use the zebrafish notochord, an organ where coin-shaped precursor cells are initially arranged in a simple unidimensional geometry. These cells then differentiate into vacuolated and sheath cells. Using newly developed transgenic tools together with in vivo imaging, we identify jag1a and her6/her9 as the main components of a Notch GRN that generates a lateral inhibition pattern and determines cell fate. Making use of this experimental system and mathematical modeling we show that lateral inhibition patterning is promoted when ligand-receptor interactions are stronger within the same cell than in neighboring cells. Altogether, we establish the zebrafish notochord as an experimental system to study pattern generation, and identify and characterize how the properties of GRNs determine self-organization of gene patterning and cell fate.
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Affiliation(s)
- Héctor Sánchez-Iranzo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Aliaksandr Halavatyi
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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13
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Abstract
Microscopy image analysis has recently made enormous progress both in terms of accuracy and speed thanks to machine learning methods and improved computational resources. This greatly facilitates the online adaptation of microscopy experimental plans using real-time information of the observed systems and their environments. Applications in which reactiveness is needed are multifarious. Here we report MicroMator, an open and flexible software for defining and driving reactive microscopy experiments. It provides a Python software environment and an extensible set of modules that greatly facilitate the definition of events with triggers and effects interacting with the experiment. We provide a pedagogic example performing dynamic adaptation of fluorescence illumination on bacteria, and demonstrate MicroMator’s potential via two challenging case studies in yeast to single-cell control and single-cell recombination, both requiring real-time tracking and light targeting at the single-cell level. In microscopy, applications in which reactiveness is needed are multifarious. Here the authors report MicroMator, a Python software package for reactive experiments, which they use for applications requiring real-time tracking and light-targeting at the single-cell level.
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14
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Mohale M, Gundampati RK, Krishnaswamy Suresh Kumar T, Heyes CD. Site-specific labeling and functional efficiencies of human fibroblast growth Factor-1 with a range of fluorescent Dyes in the flexible N-Terminal region and a rigid β-turn region. Anal Biochem 2022; 640:114524. [PMID: 34933004 DOI: 10.1016/j.ab.2021.114524] [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: 11/10/2021] [Accepted: 12/08/2021] [Indexed: 11/01/2022]
Abstract
Human fibroblast growth factor-1 (hFGF1) binding to its receptor and heparin play critical roles in cell proliferation, angiogenesis and wound healing but is also implicated in cancer. Fluorescence imaging is a powerful approach to study such protein interactions, but it is not always obvious if the site chosen will be efficiently labeled, often relying on trial-and-error. To provide a more systematic approach towards an efficient site-specific labeling strategy, we labeled two structurally distinct regions of the protein - the flexible N-terminus and a rigid loop. Several dyes were chosen to cover the visible region and to investigate how the structure of the dye affects the labeling efficiency. Flexibility in either the protein labeling site or the dye structure was found to result in high labeling efficiency, but flexibility in both resulted in a significant decrease in labeling efficiency. Conversely, too much rigidity in both can result in dye-protein interactions that can aggregate the protein. Importantly, site-specifically labeling hFGF1 in these regions maintained biological activity. These results could be applicable to other proteins by considering the flexibility of both the protein labeling site and the dye structure.
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Affiliation(s)
- Mamello Mohale
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA
| | - Ravi Kumar Gundampati
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA
| | | | - Colin D Heyes
- Department of Chemistry and Biochemistry, University of Arkansas, 345 N. Campus Drive, Fayetteville, AR, 72701, USA.
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15
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So C, Menelaou K, Uraji J, Harasimov K, Steyer AM, Seres KB, Bucevičius J, Lukinavičius G, Möbius W, Sibold C, Tandler-Schneider A, Eckel H, Moltrecht R, Blayney M, Elder K, Schuh M. Mechanism of spindle pole organization and instability in human oocytes. Science 2022; 375:eabj3944. [PMID: 35143306 DOI: 10.1126/science.abj3944] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human oocytes are prone to assembling meiotic spindles with unstable poles, which can favor aneuploidy in human eggs. The underlying causes of spindle instability are unknown. We found that NUMA (nuclear mitotic apparatus protein)-mediated clustering of microtubule minus ends focused the spindle poles in human, bovine, and porcine oocytes and in mouse oocytes depleted of acentriolar microtubule-organizing centers (aMTOCs). However, unlike human oocytes, bovine, porcine, and aMTOC-free mouse oocytes have stable spindles. We identified the molecular motor KIFC1 (kinesin superfamily protein C1) as a spindle-stabilizing protein that is deficient in human oocytes. Depletion of KIFC1 recapitulated spindle instability in bovine and aMTOC-free mouse oocytes, and the introduction of exogenous KIFC1 rescued spindle instability in human oocytes. Thus, the deficiency of KIFC1 contributes to spindle instability in human oocytes.
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Affiliation(s)
- Chun So
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Katerina Menelaou
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Bourn Hall Clinic, Cambridge, UK
| | - Julia Uraji
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Bourn Hall Clinic, Cambridge, UK
| | - Katarina Harasimov
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Anna M Steyer
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - K Bianka Seres
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Bourn Hall Clinic, Cambridge, UK
| | - Jonas Bucevičius
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Gražvydas Lukinavičius
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | | | | | - Heike Eckel
- Kinderwunschzentrum Göttingen, Göttingen, Germany
| | | | | | | | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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16
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Abstract
Optogenetics is a powerful technique that allows the control of protein function with high spatiotemporal precision using light. Here, we describe the application of this method to control tissue mechanics during Drosophila embryonic development. We detail optogenetic protocols to either increase or decrease cell contractility and analyze the interplay between cell-cell interaction, tissue geometry, and force transmission during gastrulation.
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Affiliation(s)
- Daniel Krueger
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit, Heidelberg, Germany
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), Utrecht, The Netherlands
| | - Stefano De Renzis
- European Molecular Biology Laboratory (EMBL), Developmental Biology Unit, Heidelberg, Germany.
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17
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A Protocol for Studying Transcription Factor Dynamics Using Fast Single-Particle Tracking and Spot-On Model-Based Analysis. Methods Mol Biol 2022; 2458:151-174. [PMID: 35103967 DOI: 10.1007/978-1-0716-2140-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Single-particle tracking (SPT) makes it possible to directly observe single protein diffusion dynamics in living cells over time. Thus, SPT has emerged as a powerful method to quantify the dynamics of nuclear proteins such as transcription factors (TFs). Here, we provide a protocol for conducting and analyzing SPT experiments with a focus on fast tracking ("fastSPT") of TFs in mammalian cells. First, we explore how to engineer and prepare cells for SPT experiments. Next, we examine how to optimize SPT experiments by imaging at low densities to minimize tracking errors and by using stroboscopic excitation to minimize motion-blur. Next, we discuss how to convert raw SPT data into single-particle trajectories. Finally, we illustrate how to analyze these trajectories using the kinetic modeling package Spot-On. We discuss how to use Spot-On to fit histograms of displacements and extract useful information such as the fraction of TFs that are bound and freely diffusing, and their associated diffusion coefficients.
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18
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Hickey SM, Ung B, Bader C, Brooks R, Lazniewska J, Johnson IRD, Sorvina A, Logan J, Martini C, Moore CR, Karageorgos L, Sweetman MJ, Brooks DA. Fluorescence Microscopy-An Outline of Hardware, Biological Handling, and Fluorophore Considerations. Cells 2021; 11:35. [PMID: 35011596 PMCID: PMC8750338 DOI: 10.3390/cells11010035] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 12/16/2022] Open
Abstract
Fluorescence microscopy has become a critical tool for researchers to understand biological processes at the cellular level. Micrographs from fixed and live-cell imaging procedures feature in a plethora of scientific articles for the field of cell biology, but the complexities of fluorescence microscopy as an imaging tool can sometimes be overlooked or misunderstood. This review seeks to cover the three fundamental considerations when designing fluorescence microscopy experiments: (1) hardware availability; (2) amenability of biological models to fluorescence microscopy; and (3) suitability of imaging agents for intended applications. This review will help equip the reader to make judicious decisions when designing fluorescence microscopy experiments that deliver high-resolution and informative images for cell biology.
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Affiliation(s)
- Shane M. Hickey
- Clinical and Health Sciences, University of South Australia, Adelaide 5000, Australia; (C.B.); (R.B.); (J.L.); (I.R.D.J.); (A.S.); (J.L.); (C.M.); (C.R.M.); (L.K.); (M.J.S.); (D.A.B.)
| | - Ben Ung
- Clinical and Health Sciences, University of South Australia, Adelaide 5000, Australia; (C.B.); (R.B.); (J.L.); (I.R.D.J.); (A.S.); (J.L.); (C.M.); (C.R.M.); (L.K.); (M.J.S.); (D.A.B.)
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19
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Recent advances in the standardization of fluorescence microscopy for quantitative image analysis. Biophys Rev 2021; 14:33-39. [DOI: 10.1007/s12551-021-00871-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/22/2021] [Indexed: 12/19/2022] Open
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20
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Zhang L, Perez-Romero C, Dostatni N, Fradin C. Using FCS to accurately measure protein concentration in the presence of noise and photobleaching. Biophys J 2021; 120:4230-4241. [PMID: 34242593 PMCID: PMC8516637 DOI: 10.1016/j.bpj.2021.06.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/02/2021] [Accepted: 06/28/2021] [Indexed: 11/24/2022] Open
Abstract
Quantitative cell biology requires precise and accurate concentration measurements, resolved both in space and time. Fluorescence correlation spectroscopy (FCS) has been held as a promising technique to perform such measurements because the fluorescence fluctuations it relies on are directly dependent on the absolute number of fluorophores in the detection volume. However, the most interesting applications are in cells, where autofluorescence and confinement result in strong background noise and important levels of photobleaching. Both noise and photobleaching introduce systematic bias in FCS concentration measurements and need to be corrected for. Here, we propose to make use of the photobleaching inevitably occurring in confined environments to perform series of FCS measurements at different fluorophore concentration, which we show allows a precise in situ measurement of both background noise and molecular brightness. Such a measurement can then be used as a calibration to transform confocal intensity images into concentration maps. The power of this approach is first illustrated with in vitro measurements using different dye solutions, then its applicability for in vivo measurements is demonstrated in Drosophila embryos for a model nuclear protein and for two morphogens, Bicoid and Capicua.
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Affiliation(s)
- Lili Zhang
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Carmina Perez-Romero
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada; Institut Curie, PSL University, CNRS, Paris, France; Nuclear Dynamics, Sorbonne University, Paris, France
| | - Nathalie Dostatni
- Institut Curie, PSL University, CNRS, Paris, France; Nuclear Dynamics, Sorbonne University, Paris, France
| | - Cécile Fradin
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
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21
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Viswanathan R, Hartmann J, Pallares Cartes C, De Renzis S. Desensitisation of Notch signalling through dynamic adaptation in the nucleus. EMBO J 2021; 40:e107245. [PMID: 34396565 PMCID: PMC8441390 DOI: 10.15252/embj.2020107245] [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: 11/06/2020] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 11/13/2022] Open
Abstract
During embryonic development, signalling pathways orchestrate organogenesis by controlling tissue‐specific gene expression programmes and differentiation. Although the molecular components of many common developmental signalling systems are known, our current understanding of how signalling inputs are translated into gene expression outputs in real‐time is limited. Here we employ optogenetics to control the activation of Notch signalling during Drosophila embryogenesis with minute accuracy and follow target gene expression by quantitative live imaging. Light‐induced nuclear translocation of the Notch Intracellular Domain (NICD) causes a rapid activation of target mRNA expression. However, target gene transcription gradually decays over time despite continuous photo‐activation and nuclear NICD accumulation, indicating dynamic adaptation to the signalling input. Using mathematical modelling and molecular perturbations, we show that this adaptive transcriptional response fits to known motifs capable of generating near‐perfect adaptation and can be best explained by state‐dependent inactivation at the target cis‐regulatory region. Taken together, our results reveal dynamic nuclear adaptation as a novel mechanism controlling Notch signalling output during tissue differentiation.
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Affiliation(s)
- Ranjith Viswanathan
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Jonas Hartmann
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany.,Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Stefano De Renzis
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
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22
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Fuqua T, Jordan J, Halavatyi A, Tischer C, Richter K, Crocker J. An open-source semi-automated robotics pipeline for embryo immunohistochemistry. Sci Rep 2021; 11:10314. [PMID: 33986394 PMCID: PMC8119710 DOI: 10.1038/s41598-021-89676-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/19/2021] [Indexed: 11/09/2022] Open
Abstract
A significant challenge for developmental systems biology is balancing throughput with controlled conditions that minimize experimental artifacts. Large-scale developmental screens such as unbiased mutagenesis surveys have been limited in their applicability to embryonic systems, as the technologies for quantifying precise expression patterns in whole animals has not kept pace with other sequencing-based technologies. Here, we outline an open-source semi-automated pipeline to chemically fixate, stain, and 3D-image Drosophila embryos. Central to this pipeline is a liquid handling robot, Flyspresso, which automates the steps of classical embryo fixation and staining. We provide the schematics and an overview of the technology for an engineer or someone equivalently trained to reproduce and further improve upon Flyspresso, and highlight the Drosophila embryo fixation and colorimetric or antibody staining protocols. Additionally, we provide a detailed overview and stepwise protocol for our adaptive-feedback pipeline for automated embryo imaging on confocal microscopes. We demonstrate the efficiency of this pipeline compared to classical techniques, and how it can be repurposed or scaled to other protocols and biological systems. We hope our pipeline will serve as a platform for future research, allowing a broader community of users to build, execute, and share similar experiments.
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Affiliation(s)
- Timothy Fuqua
- European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for Joint PhD Degree Between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Jeff Jordan
- Janelia Research Campus, 19700 Helix Dr, Ashburn, VA, 20147, USA
| | | | | | | | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Germany.
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23
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Mengoli V, Jonak K, Lyzak O, Lamb M, Lister LM, Lodge C, Rojas J, Zagoriy I, Herbert M, Zachariae W. Deprotection of centromeric cohesin at meiosis II requires APC/C activity but not kinetochore tension. EMBO J 2021; 40:e106812. [PMID: 33644894 PMCID: PMC8013787 DOI: 10.15252/embj.2020106812] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 01/03/2023] Open
Abstract
Genome haploidization involves sequential loss of cohesin from chromosome arms and centromeres during two meiotic divisions. At centromeres, cohesin's Rec8 subunit is protected from separase cleavage at meiosis I and then deprotected to allow its cleavage at meiosis II. Protection of centromeric cohesin by shugoshin-PP2A seems evolutionarily conserved. However, deprotection has been proposed to rely on spindle forces separating the Rec8 protector from cohesin at metaphase II in mammalian oocytes and on APC/C-dependent destruction of the protector at anaphase II in yeast. Here, we have activated APC/C in the absence of sister kinetochore biorientation at meiosis II in yeast and mouse oocytes, and find that bipolar spindle forces are dispensable for sister centromere separation in both systems. Furthermore, we show that at least in yeast, protection of Rec8 by shugoshin and inhibition of separase by securin are both required for the stability of centromeric cohesin at metaphase II. Our data imply that related mechanisms preserve the integrity of dyad chromosomes during the short metaphase II of yeast and the prolonged metaphase II arrest of mammalian oocytes.
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Affiliation(s)
- Valentina Mengoli
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
Institute for Research in BiomedicineUniversità della Svizzera ItalianaBellinzonaSwitzerland
| | - Katarzyna Jonak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Oleksii Lyzak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Mahdi Lamb
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Lisa M Lister
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Chris Lodge
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Julie Rojas
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Ievgeniia Zagoriy
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
EMBL HeidelbergHeidelbergGermany
| | - Mary Herbert
- Biosciences InstituteCentre for LifeTimes SquareNewcastle UniversityNewcastle upon TyneUK
| | - Wolfgang Zachariae
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
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24
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Protocol for the determination of intracellular phase separation thresholds. STAR Protoc 2021; 2:100308. [PMID: 33554143 PMCID: PMC7856470 DOI: 10.1016/j.xpro.2021.100308] [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] [Indexed: 11/20/2022] Open
Abstract
To date, phase separation studies have largely been limited to in vitro assays using non-native conditions and aggregation-prone recombinant proteins that are often difficult to purify. This protocol describes the determination of relative protein concentration thresholds for phase separation through fluorescent imaging of GFP-tagged proteins in cells. The commercial availability of various plasmids and antibodies, as well as advances in gene editing, allow this procedure to be modified for the study of various phase-separating proteins in their relevant contexts. For complete details on the use and execution of this protocol, please refer to Lee et al. (2020). Determining relative protein concentration thresholds for phase separation in cells Fluorescent imaging and analysis of GFP-tagged proteins at single-cell resolution Immunofluorescent staining and imaging of endogenous proteins Quantification of endogenous protein levels relative to the threshold concentration
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25
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Courtois A, Yoshida S, Takenouchi O, Asai K, Kitajima TS. Stable kinetochore-microtubule attachments restrict MTOC position and spindle elongation in oocytes. EMBO Rep 2021; 22:e51400. [PMID: 33655692 PMCID: PMC8024892 DOI: 10.15252/embr.202051400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/14/2021] [Accepted: 01/28/2021] [Indexed: 01/13/2023] Open
Abstract
In mouse oocytes, acentriolar MTOCs functionally replace centrosomes and act as microtubule nucleation sites. Microtubules nucleated from MTOCs initially assemble into an unorganized ball‐like structure, which then transforms into a bipolar spindle carrying MTOCs at its poles, a process called spindle bipolarization. In mouse oocytes, spindle bipolarization is promoted by kinetochores but the mechanism by which kinetochore–microtubule attachments contribute to spindle bipolarity remains unclear. This study demonstrates that the stability of kinetochore–microtubule attachment is essential for confining MTOC positions at the spindle poles and for limiting spindle elongation. MTOC sorting is gradual and continues even in the metaphase spindle. When stable kinetochore–microtubule attachments are disrupted, the spindle is unable to restrict MTOCs at its poles and fails to terminate its elongation. Stable kinetochore fibers are directly connected to MTOCs and to the spindle poles. These findings suggest a role for stable kinetochore–microtubule attachments in fine‐tuning acentrosomal spindle bipolarity.
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Affiliation(s)
- Aurélien Courtois
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Shuhei Yoshida
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Osamu Takenouchi
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Kohei Asai
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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26
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Fuqua T, Jordan J, van Breugel ME, Halavatyi A, Tischer C, Polidoro P, Abe N, Tsai A, Mann RS, Stern DL, Crocker J. Dense and pleiotropic regulatory information in a developmental enhancer. Nature 2020; 587:235-239. [PMID: 33057197 DOI: 10.1038/s41586-020-2816-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/22/2020] [Indexed: 01/08/2023]
Abstract
Changes in gene regulation underlie much of phenotypic evolution1. However, our understanding of the potential for regulatory evolution is biased, because most evidence comes from either natural variation or limited experimental perturbations2. Using an automated robotics pipeline, we surveyed an unbiased mutation library for a developmental enhancer in Drosophila melanogaster. We found that almost all mutations altered gene expression and that parameters of gene expression-levels, location, and state-were convolved. The widespread pleiotropic effects of most mutations may constrain the evolvability of developmental enhancers. Consistent with these observations, comparisons of diverse Drosophila larvae revealed apparent biases in the phenotypes influenced by the enhancer. Developmental enhancers may encode a higher density of regulatory information than has been appreciated previously, imposing constraints on regulatory evolution.
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Affiliation(s)
- Timothy Fuqua
- European Molecular Biology Laboratory, Heidelberg, Germany.,Joint PhD Collaboration, EMBL and Faculty of Biosciences Heidelberg University, Heidelberg, Germany
| | | | | | | | | | | | - Namiko Abe
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Albert Tsai
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Richard S Mann
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | | | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Germany.
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27
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Krueger D, Pallares Cartes C, Makaske T, De Renzis S. βH-spectrin is required for ratcheting apical pulsatile constrictions during tissue invagination. EMBO Rep 2020; 21:e49858. [PMID: 32588528 PMCID: PMC7403717 DOI: 10.15252/embr.201949858] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 05/13/2020] [Accepted: 05/20/2020] [Indexed: 01/09/2023] Open
Abstract
Actomyosin‐mediated apical constriction drives a wide range of morphogenetic processes. Activation of myosin‐II initiates pulsatile cycles of apical constrictions followed by either relaxation or stabilization (ratcheting) of the apical surface. While relaxation leads to dissipation of contractile forces, ratcheting is critical for the generation of tissue‐level tension and changes in tissue shape. How ratcheting is controlled at the molecular level is unknown. Here, we show that the actin crosslinker βH‐spectrin is upregulated at the apical surface of invaginating mesodermal cells during Drosophila gastrulation. βH‐spectrin forms a network of filaments which co‐localize with medio‐apical actomyosin fibers, in a process that depends on the mesoderm‐transcription factor Twist and activation of Rho signaling. βH‐spectrin knockdown results in non‐ratcheted apical constrictions and inhibition of mesoderm invagination, recapitulating twist mutant embryos. βH‐spectrin is thus a key regulator of apical ratcheting during tissue invagination, suggesting that actin cross‐linking plays a critical role in this process.
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Affiliation(s)
- Daniel Krueger
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Thijs Makaske
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Stefano De Renzis
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
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28
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Knox SL, Steinauer A, Alpha-Cobb G, Trexler A, Rhoades E, Schepartz A. Quantification of protein delivery in live cells using fluorescence correlation spectroscopy. Methods Enzymol 2020; 641:477-505. [PMID: 32713536 DOI: 10.1016/bs.mie.2020.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Fluorescence correlation spectroscopy (FCS) is a quantitative single-molecule method that measures the concentration and rate of diffusion of fluorophore-tagged molecules, both large and small, in vitro and within live cells, and even within discrete cellular compartments. FCS is exceptionally well-suited to directly quantify the efficiency of intracellular protein delivery-specifically, how well different "cell-penetrating" proteins and peptides guide proteinaceous materials into the cytosol and nuclei of live mammalian cells. This article provides an overview of the procedures necessary to execute robust FCS experiments and evaluate endosomal escape efficiencies: preparation of fluorophore-tagged proteins, incubation with mammalian cells and preparation of FCS samples, setup and execution of an FCS experiment, and a detailed discussion of and custom MATLAB® script for analyzing the resulting autocorrelation curves in the context of appropriate diffusion models.
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Affiliation(s)
- Susan L Knox
- Department of Chemistry, University of California, Berkeley, CA, United States
| | - Angela Steinauer
- Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Garrett Alpha-Cobb
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Adam Trexler
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States
| | - Alanna Schepartz
- Department of Chemistry, University of California, Berkeley, CA, United States; Department of Molecular and Cell Biology, University of California, Berkeley, CA, United States.
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29
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Suter DM. Transcription Factors and DNA Play Hide and Seek. Trends Cell Biol 2020; 30:491-500. [PMID: 32413318 DOI: 10.1016/j.tcb.2020.03.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 01/12/2023]
Abstract
Transcription factors (TFs) bind to specific DNA motifs to regulate the expression of target genes. To reach their binding sites, TFs diffuse in 3D and perform local motions such as 1D sliding, hopping, or intersegmental transfer. TF-DNA interactions depend on multiple parameters, such as the chromatin environment, TF partitioning into distinct subcellular regions, and cooperativity with other DNA-binding proteins. In this review, how current understanding of the search process has initially been shaped by prokaryotic studies is discussed, as well as what is known about the parameters regulating TF search efficiency in the context of the complex eukaryotic chromatin landscape.
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Affiliation(s)
- David M Suter
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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30
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So C, Seres KB, Steyer AM, Mönnich E, Clift D, Pejkovska A, Möbius W, Schuh M. A liquid-like spindle domain promotes acentrosomal spindle assembly in mammalian oocytes. Science 2020; 364:364/6447/eaat9557. [PMID: 31249032 DOI: 10.1126/science.aat9557] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/02/2019] [Indexed: 12/22/2022]
Abstract
Mammalian oocytes segregate chromosomes with a microtubule spindle that lacks centrosomes, but the mechanisms by which acentrosomal spindles are organized and function are largely unclear. In this study, we identify a conserved subcellular structure in mammalian oocytes that forms by phase separation. This structure, which we term the liquid-like meiotic spindle domain (LISD), permeates the spindle poles and forms dynamic protrusions that extend well beyond the spindle. The LISD selectively concentrates multiple microtubule regulatory factors and allows them to diffuse rapidly within the spindle volume. Disruption of the LISD via different means disperses these factors and leads to severe spindle assembly defects. Our data suggest a model whereby the LISD promotes meiotic spindle assembly by serving as a reservoir that sequesters and mobilizes microtubule regulatory factors in proximity to spindle microtubules.
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Affiliation(s)
- Chun So
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - K Bianka Seres
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.,Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.,Bourn Hall Clinic, Cambridge CB23 2TN, UK
| | - Anna M Steyer
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany.,Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany
| | - Eike Mönnich
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Dean Clift
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Anastasija Pejkovska
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany.,Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. .,Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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31
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Lundberg E, Borner GHH. Spatial proteomics: a powerful discovery tool for cell biology. Nat Rev Mol Cell Biol 2020; 20:285-302. [PMID: 30659282 DOI: 10.1038/s41580-018-0094-y] [Citation(s) in RCA: 264] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Protein subcellular localization is tightly controlled and intimately linked to protein function in health and disease. Capturing the spatial proteome - that is, the localizations of proteins and their dynamics at the subcellular level - is therefore essential for a complete understanding of cell biology. Owing to substantial advances in microscopy, mass spectrometry and machine learning applications for data analysis, the field is now mature for proteome-wide investigations of spatial cellular regulation. Studies of the human proteome have begun to reveal a complex architecture, including single-cell variations, dynamic protein translocations, changing interaction networks and proteins localizing to multiple compartments. Furthermore, several studies have successfully harnessed the power of comparative spatial proteomics as a discovery tool to unravel disease mechanisms. We are at the beginning of an era in which spatial proteomics finally integrates with cell biology and medical research, thereby paving the way for unbiased systems-level insights into cellular processes. Here, we discuss current methods for spatial proteomics using imaging or mass spectrometry and specifically highlight global comparative applications. The aim of this Review is to survey the state of the field and also to encourage more cell biologists to apply spatial proteomics approaches.
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Affiliation(s)
- Emma Lundberg
- Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH - Royal Institute of Technology, Stockholm, Sweden. .,Department of Genetics, Stanford University, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Georg H H Borner
- Max Planck Institute of Biochemistry, Department of Proteomics and Signal Transduction, Martinsried, Germany.
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32
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Cattoglio C, Darzacq X, Tjian R, Hansen AS. Estimating Cellular Abundances of Halo-tagged Proteins in Live Mammalian Cells by Flow Cytometry. Bio Protoc 2020; 10:e3527. [PMID: 33654751 DOI: 10.21769/bioprotoc.3527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/24/2019] [Accepted: 01/29/2020] [Indexed: 11/02/2022] Open
Abstract
Accurate abundance measurements of cellular proteins are required to achieve a quantitative and predictive understanding of any biological process inside the cell. Existing methods to determine absolute protein abundances are labor-intensive and/or require sophisticated experimental and computational infrastructure (e.g., fluorescence correlation spectroscopy (FCS)-calibrated imaging and quantitative mass spectrometry). Here we detail a straightforward flow cytometry-based method to measure the absolute abundance of any Halo-tagged protein in live cells that uses a standard mammalian cell line with a known number of Halo-CTCF proteins recently characterized in our lab. The protocol only comprises a few steps. First, a cell line expressing the Halo-tagged protein of interest is grown and labeled side-by-side with our standard line. Then, average fluorescence intensities are measured by conventional flow cytometry analysis and finally a simple calculation is applied to estimate the absolute number of the Halo-tagged protein of interest per cell. Once the protein of interest has been endogenously tagged with HaloTag, which we routinely achieve by Cas9-mediated genome editing, the presented protocol is fast, convenient, reproducible, cost-effective and readily accessible.
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Affiliation(s)
- Claudia Cattoglio
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Li Ka Shing Center for Biomedical and Health Sciences, Berkeley, CA, USA.,CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Li Ka Shing Center for Biomedical and Health Sciences, Berkeley, CA, USA.,CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Li Ka Shing Center for Biomedical and Health Sciences, Berkeley, CA, USA.,CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Anders S Hansen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Li Ka Shing Center for Biomedical and Health Sciences, Berkeley, CA, USA.,CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA, USA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA
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33
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Toro-Nahuelpan M, Zagoriy I, Senger F, Blanchoin L, Théry M, Mahamid J. Tailoring cryo-electron microscopy grids by photo-micropatterning for in-cell structural studies. Nat Methods 2020; 17:50-54. [PMID: 31740821 PMCID: PMC6949126 DOI: 10.1038/s41592-019-0630-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/07/2019] [Indexed: 01/01/2023]
Abstract
Spatially controlled cell adhesion on electron microscopy supports remains a bottleneck in specimen preparation for cellular cryo-electron tomography. Here, we describe contactless and mask-free photo-micropatterning of electron microscopy grids for site-specific deposition of extracellular matrix-related proteins. We attained refined cell positioning for micromachining by cryo-focused ion beam milling. Complex micropatterns generated predictable intracellular organization, allowing direct correlation between cell architecture and in-cell three-dimensional structural characterization of the underlying molecular machinery.
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Affiliation(s)
- Mauricio Toro-Nahuelpan
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Fabrice Senger
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Laurent Blanchoin
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
- CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hématologie, Université Paris Diderot, Paris, France
| | - Manuel Théry
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
- CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hématologie, Université Paris Diderot, Paris, France
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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34
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Toro-Nahuelpan M, Zagoriy I, Senger F, Blanchoin L, Théry M, Mahamid J. Tailoring cryo-electron microscopy grids by photo-micropatterning for in-cell structural studies. Nat Methods 2020; 17:50-54. [PMID: 31740821 DOI: 10.21203/rs.2.12377/v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/07/2019] [Indexed: 05/22/2023]
Abstract
Spatially controlled cell adhesion on electron microscopy supports remains a bottleneck in specimen preparation for cellular cryo-electron tomography. Here, we describe contactless and mask-free photo-micropatterning of electron microscopy grids for site-specific deposition of extracellular matrix-related proteins. We attained refined cell positioning for micromachining by cryo-focused ion beam milling. Complex micropatterns generated predictable intracellular organization, allowing direct correlation between cell architecture and in-cell three-dimensional structural characterization of the underlying molecular machinery.
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Affiliation(s)
- Mauricio Toro-Nahuelpan
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Fabrice Senger
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Laurent Blanchoin
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
- CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hématologie, Université Paris Diderot, Paris, France
| | - Manuel Théry
- CytomorphoLab, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
- CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hématologie, Université Paris Diderot, Paris, France
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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35
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Krueger D, Quinkler T, Mortensen SA, Sachse C, De Renzis S. Cross-linker-mediated regulation of actin network organization controls tissue morphogenesis. J Cell Biol 2019; 218:2743-2761. [PMID: 31253650 PMCID: PMC6683744 DOI: 10.1083/jcb.201811127] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 04/29/2019] [Accepted: 06/04/2019] [Indexed: 11/22/2022] Open
Abstract
Spatio-temporal organization of actomyosin contraction during epithelial morphogenesis in Drosophila is regulated by the developmental modulation of actin cross-linking through induction of Bottleneck. Bottleneck protein restrains contractility by promoting actin bundling, functioning in a similar way to Filamin and in an opposite way to Fimbrin. Contraction of cortical actomyosin networks driven by myosin activation controls cell shape changes and tissue morphogenesis during animal development. In vitro studies suggest that contractility also depends on the geometrical organization of actin filaments. Here we analyze the function of actomyosin network topology in vivo using optogenetic stimulation of myosin-II in Drosophila embryos. We show that early during cellularization, hexagonally arrayed actomyosin fibers are resilient to myosin-II activation. Actomyosin fibers then acquire a ring-like conformation and become contractile and sensitive to myosin-II. This transition is controlled by Bottleneck, a Drosophila unique protein expressed for only a short time during early cellularization, which we show regulates actin bundling. In addition, it requires two opposing actin cross-linkers, Filamin and Fimbrin. Filamin acts synergistically with Bottleneck to facilitate hexagonal patterning, while Fimbrin controls remodeling of the hexagonal network into contractile rings. Thus, actin cross-linking regulates the spatio-temporal organization of actomyosin contraction in vivo, which is critical for tissue morphogenesis.
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Affiliation(s)
- Daniel Krueger
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for joint PhD degree between European Molecular Biology Laboratory and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Theresa Quinkler
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Simon Arnold Mortensen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Carsten Sachse
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Ernst-Ruska Center for Microscopy and Spectroscopy with Electrons (ER-C-3/Structural Biology), Forschungszentrum Jülich, Jülich, Germany
| | - Stefano De Renzis
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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36
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Manning CS, Biga V, Boyd J, Kursawe J, Ymisson B, Spiller DG, Sanderson CM, Galla T, Rattray M, Papalopulu N. Quantitative single-cell live imaging links HES5 dynamics with cell-state and fate in murine neurogenesis. Nat Commun 2019; 10:2835. [PMID: 31249377 PMCID: PMC6597611 DOI: 10.1038/s41467-019-10734-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 05/17/2019] [Indexed: 12/17/2022] Open
Abstract
During embryogenesis cells make fate decisions within complex tissue environments. The levels and dynamics of transcription factor expression regulate these decisions. Here, we use single cell live imaging of an endogenous HES5 reporter and absolute protein quantification to gain a dynamic view of neurogenesis in the embryonic mammalian spinal cord. We report that dividing neural progenitors show both aperiodic and periodic HES5 protein fluctuations. Mathematical modelling suggests that in progenitor cells the HES5 oscillator operates close to its bifurcation boundary where stochastic conversions between dynamics are possible. HES5 expression becomes more frequently periodic as cells transition to differentiation which, coupled with an overall decline in HES5 expression, creates a transient period of oscillations with higher fold expression change. This increases the decoding capacity of HES5 oscillations and correlates with interneuron versus motor neuron cell fate. Thus, HES5 undergoes complex changes in gene expression dynamics as cells differentiate.
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Affiliation(s)
- Cerys S. Manning
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Veronica Biga
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - James Boyd
- Department of Cellular and Molecular Physiology, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - Jochen Kursawe
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Bodvar Ymisson
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - David G. Spiller
- School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Christopher M. Sanderson
- Department of Cellular and Molecular Physiology, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - Tobias Galla
- Theoretical Physics Division, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL UK
| | - Magnus Rattray
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Nancy Papalopulu
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
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37
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Cattoglio C, Pustova I, Walther N, Ho JJ, Hantsche-Grininger M, Inouye CJ, Hossain MJ, Dailey GM, Ellenberg J, Darzacq X, Tjian R, Hansen AS. Determining cellular CTCF and cohesin abundances to constrain 3D genome models. eLife 2019; 8:e40164. [PMID: 31205001 PMCID: PMC6579579 DOI: 10.7554/elife.40164] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 03/28/2019] [Indexed: 01/02/2023] Open
Abstract
Achieving a quantitative and predictive understanding of 3D genome architecture remains a major challenge, as it requires quantitative measurements of the key proteins involved. Here, we report the quantification of CTCF and cohesin, two causal regulators of topologically associating domains (TADs) in mammalian cells. Extending our previous imaging studies (Hansen et al., 2017), we estimate bounds on the density of putatively DNA loop-extruding cohesin complexes and CTCF binding site occupancy. Furthermore, co-immunoprecipitation studies of an endogenously tagged subunit (Rad21) suggest the presence of cohesin dimers and/or oligomers. Finally, based on our cell lines with accurately measured protein abundances, we report a method to conveniently determine the number of molecules of any Halo-tagged protein in the cell. We anticipate that our results and the established tool for measuring cellular protein abundances will advance a more quantitative understanding of 3D genome organization, and facilitate protein quantification, key to comprehend diverse biological processes.
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Affiliation(s)
- Claudia Cattoglio
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - Iryna Pustova
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - Nike Walther
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Jaclyn J Ho
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | | | - Carla J Inouye
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - M Julius Hossain
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Gina M Dailey
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Jan Ellenberg
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Robert Tjian
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - Anders S Hansen
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
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38
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Holzmann J, Politi AZ, Nagasaka K, Hantsche-Grininger M, Walther N, Koch B, Fuchs J, Dürnberger G, Tang W, Ladurner R, Stocsits RR, Busslinger GA, Novák B, Mechtler K, Davidson IF, Ellenberg J, Peters JM. Absolute quantification of cohesin, CTCF and their regulators in human cells. eLife 2019; 8:e46269. [PMID: 31204999 PMCID: PMC6606026 DOI: 10.7554/elife.46269] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/13/2019] [Indexed: 12/15/2022] Open
Abstract
The organisation of mammalian genomes into loops and topologically associating domains (TADs) contributes to chromatin structure, gene expression and recombination. TADs and many loops are formed by cohesin and positioned by CTCF. In proliferating cells, cohesin also mediates sister chromatid cohesion, which is essential for chromosome segregation. Current models of chromatin folding and cohesion are based on assumptions of how many cohesin and CTCF molecules organise the genome. Here we have measured absolute copy numbers and dynamics of cohesin, CTCF, NIPBL, WAPL and sororin by mass spectrometry, fluorescence-correlation spectroscopy and fluorescence recovery after photobleaching in HeLa cells. In G1-phase, there are ~250,000 nuclear cohesin complexes, of which ~ 160,000 are chromatin-bound. Comparison with chromatin immunoprecipitation-sequencing data implies that some genomic cohesin and CTCF enrichment sites are unoccupied in single cells at any one time. We discuss the implications of these findings for how cohesin can contribute to genome organisation and cohesion.
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Affiliation(s)
- Johann Holzmann
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Antonio Z Politi
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Kota Nagasaka
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | | | - Nike Walther
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Birgit Koch
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Johannes Fuchs
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Gerhard Dürnberger
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Wen Tang
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Rene Ladurner
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Roman R Stocsits
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Georg A Busslinger
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Béla Novák
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)Vienna Biocenter (VBC)ViennaAustria
- Gregor Mendel Institute, Austrian Academy of SciencesVienna Biocenter (VBC)ViennaAustria
| | - Iain Finley Davidson
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
| | - Jan Ellenberg
- Cell Biology and Biophysics UnitEuropean Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC)ViennaAustria
- Medical University of ViennaViennaAustria
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39
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Krueger D, Tardivo P, Nguyen C, De Renzis S. Downregulation of basal myosin-II is required for cell shape changes and tissue invagination. EMBO J 2018; 37:embj.2018100170. [PMID: 30442834 PMCID: PMC6276876 DOI: 10.15252/embj.2018100170] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/08/2018] [Accepted: 10/12/2018] [Indexed: 11/29/2022] Open
Abstract
Tissue invagination drives embryo remodeling and assembly of internal organs during animal development. While the role of actomyosin‐mediated apical constriction in initiating inward folding is well established, computational models suggest relaxation of the basal surface as an additional requirement. However, the lack of genetic mutations interfering specifically with basal relaxation has made it difficult to test its requirement during invagination so far. Here we use optogenetics to quantitatively control myosin‐II levels at the basal surface of invaginating cells during Drosophila gastrulation. We show that while basal myosin‐II is lost progressively during ventral furrow formation, optogenetics allows the maintenance of pre‐invagination levels over time. Quantitative imaging demonstrates that optogenetic activation prior to tissue bending slows down cell elongation and blocks invagination. Activation after cell elongation and tissue bending has initiated inhibits cell shortening and folding of the furrow into a tube‐like structure. Collectively, these data demonstrate the requirement of myosin‐II polarization and basal relaxation throughout the entire invagination process.
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Affiliation(s)
- Daniel Krueger
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Pietro Tardivo
- European Molecular Biology Laboratory, Heidelberg, Germany.,IMP, Vienna, Austria
| | - Congtin Nguyen
- European Molecular Biology Laboratory, Heidelberg, Germany.,Northeastern University, Boston, MA, USA
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40
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Mann BJ, Wadsworth P. Distribution of Eg5 and TPX2 in mitosis: Insight from CRISPR tagged cells. Cytoskeleton (Hoboken) 2018; 75:508-521. [DOI: 10.1002/cm.21486] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/11/2018] [Accepted: 07/30/2018] [Indexed: 11/07/2022]
Affiliation(s)
- B. J. Mann
- Department of Biology, Program in Molecular and Cellular Biology University of Massachusetts Amherst Massachusetts
| | - P. Wadsworth
- Department of Biology, Program in Molecular and Cellular Biology University of Massachusetts Amherst Massachusetts
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41
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Multivariate Control of Transcript to Protein Variability in Single Mammalian Cells. Cell Syst 2018; 7:398-411.e6. [DOI: 10.1016/j.cels.2018.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 06/28/2018] [Accepted: 09/05/2018] [Indexed: 12/28/2022]
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Cai Y, Hossain MJ, Hériché JK, Politi AZ, Walther N, Koch B, Wachsmuth M, Nijmeijer B, Kueblbeck M, Martinic-Kavur M, Ladurner R, Alexander S, Peters JM, Ellenberg J. Experimental and computational framework for a dynamic protein atlas of human cell division. Nature 2018; 561:411-415. [PMID: 30202089 DOI: 10.1038/s41586-018-0518-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/25/2018] [Indexed: 11/09/2022]
Abstract
Essential biological functions, such as mitosis, require tight coordination of hundreds of proteins in space and time. Localization, the timing of interactions and changes in cellular structure are all crucial to ensure the correct assembly, function and regulation of protein complexes1-4. Imaging of live cells can reveal protein distributions and dynamics but experimental and theoretical challenges have prevented the collection of quantitative data, which are necessary for the formulation of a model of mitosis that comprehensively integrates information and enables the analysis of the dynamic interactions between the molecular parts of the mitotic machinery within changing cellular boundaries. Here we generate a canonical model of the morphological changes during the mitotic progression of human cells on the basis of four-dimensional image data. We use this model to integrate dynamic three-dimensional concentration data of many fluorescently knocked-in mitotic proteins, imaged by fluorescence correlation spectroscopy-calibrated microscopy5. The approach taken here to generate a dynamic protein atlas of human cell division is generic; it can be applied to systematically map and mine dynamic protein localization networks that drive cell division in different cell types, and can be conceptually transferred to other cellular functions.
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Affiliation(s)
- Yin Cai
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Roche Diagnostics, Waiblingen, Germany
| | - M Julius Hossain
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Antonio Z Politi
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Nike Walther
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Birgit Koch
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Malte Wachsmuth
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Luxendo GmbH, Heidelberg, Germany
| | - Bianca Nijmeijer
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Moritz Kueblbeck
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Marina Martinic-Kavur
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.,Genos, Glycoscience Research Laboratory, Zagreb, Croatia
| | - Rene Ladurner
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.,Stanford School of Medicine, Stanford, CA, USA
| | | | | | - Jan Ellenberg
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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Walther N, Hossain MJ, Politi AZ, Koch B, Kueblbeck M, Ødegård-Fougner Ø, Lampe M, Ellenberg J. A quantitative map of human Condensins provides new insights into mitotic chromosome architecture. J Cell Biol 2018; 217:2309-2328. [PMID: 29632028 PMCID: PMC6028534 DOI: 10.1083/jcb.201801048] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 12/29/2022] Open
Abstract
The two Condensin complexes in human cells are essential for mitotic chromosome structure. We used homozygous genome editing to fluorescently tag Condensin I and II subunits and mapped their absolute abundance, spacing, and dynamic localization during mitosis by fluorescence correlation spectroscopy (FSC)-calibrated live-cell imaging and superresolution microscopy. Although ∼35,000 Condensin II complexes are stably bound to chromosomes throughout mitosis, ∼195,000 Condensin I complexes dynamically bind in two steps: prometaphase and early anaphase. The two Condensins rarely colocalize at the chromatid axis, where Condensin II is centrally confined, but Condensin I reaches ∼50% of the chromatid diameter from its center. Based on our comprehensive quantitative data, we propose a three-step hierarchical loop model of mitotic chromosome compaction: Condensin II initially fixes loops of a maximum size of ∼450 kb at the chromatid axis, whose size is then reduced by Condensin I binding to ∼90 kb in prometaphase and ∼70 kb in anaphase, achieving maximum chromosome compaction upon sister chromatid segregation.
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Affiliation(s)
- Nike Walther
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - M Julius Hossain
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Z Politi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Birgit Koch
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Moritz Kueblbeck
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Øyvind Ødegård-Fougner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marko Lampe
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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Izquierdo E, Quinkler T, De Renzis S. Guided morphogenesis through optogenetic activation of Rho signalling during early Drosophila embryogenesis. Nat Commun 2018; 9:2366. [PMID: 29915285 PMCID: PMC6006163 DOI: 10.1038/s41467-018-04754-z] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 05/23/2018] [Indexed: 11/26/2022] Open
Abstract
During organismal development, cells undergo complex changes in shape whose causal relationship to individual morphogenetic processes remains unclear. The modular nature of such processes suggests that it should be possible to isolate individual modules, determine the minimum set of requirements sufficient to drive tissue remodeling, and re-construct morphogenesis. Here we use optogenetics to reconstitute epithelial folding in embryonic Drosophila tissues that otherwise would not undergo invagination. We show that precise spatial and temporal activation of Rho signaling is sufficient to trigger apical constriction and tissue folding. Induced furrows can occur at any position along the dorsal–ventral or anterior–posterior embryo axis in response to the spatial pattern and level of optogenetic activation. Thus, epithelial folding is a direct function of the spatio-temporal organization and strength of Rho signaling that on its own is sufficient to drive tissue internalization independently of any pre-determined condition or differentiation program associated with endogenous invagination processes. Optogenetics is opening the possibility to not only perturb morphogenesis, but also to guide it. Here, the authors use this technique to reconstruct epithelial folding in Drosophila embryos and study the relationship between strength of Rho activation, apical constrictions, and tissue invagination.
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Koch B, Nijmeijer B, Kueblbeck M, Cai Y, Walther N, Ellenberg J. Generation and validation of homozygous fluorescent knock-in cells using CRISPR-Cas9 genome editing. Nat Protoc 2018; 13:1465-1487. [PMID: 29844520 PMCID: PMC6556379 DOI: 10.1038/nprot.2018.042] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Gene tagging with fluorescent proteins is essential for investigations of the dynamic properties of cellular proteins. CRISPR-Cas9 technology is a powerful tool for inserting fluorescent markers into all alleles of the gene of interest (GOI) and allows functionality and physiological expression of the fusion protein. It is essential to evaluate such genome-edited cell lines carefully in order to preclude off-target effects caused by (i) incorrect insertion of the fluorescent protein, (ii) perturbation of the fusion protein by the fluorescent proteins or (iii) nonspecific genomic DNA damage by CRISPR-Cas9. In this protocol, we provide a step-by-step description of our systematic pipeline to generate and validate homozygous fluorescent knock-in cell lines.We have used the paired Cas9D10A nickase approach to efficiently insert tags into specific genomic loci via homology-directed repair (HDR) with minimal off-target effects. It is time-consuming and costly to perform whole-genome sequencing of each cell clone to check for spontaneous genetic variations occurring in mammalian cell lines. Therefore, we have developed an efficient validation pipeline of the generated cell lines consisting of junction PCR, Southern blotting analysis, Sanger sequencing, microscopy, western blotting analysis and live-cell imaging for cell-cycle dynamics. This protocol takes between 6 and 9 weeks. With this protocol, up to 70% of the targeted genes can be tagged homozygously with fluorescent proteins, thus resulting in physiological levels and phenotypically functional expression of the fusion proteins.
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Affiliation(s)
- Birgit Koch
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- current address: Max Planck Insitute for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany
| | | | | | - Yin Cai
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- current address: Roche SIS, Maybachstr. 30, 71332 Waiblingen, Germany
| | - Nike Walther
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | - Jan Ellenberg
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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