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de-Carvalho J, Tlili S, Saunders TE, Telley IA. The positioning mechanics of microtubule asters in Drosophila embryo explants. eLife 2024; 12:RP90541. [PMID: 38426416 PMCID: PMC10911390 DOI: 10.7554/elife.90541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
Microtubule asters are essential in localizing the action of microtubules in processes including mitosis and organelle positioning. In large cells, such as the one-cell sea urchin embryo, aster dynamics are dominated by hydrodynamic pulling forces. However, in systems with more densely positioned nuclei such as the early Drosophila embryo, which packs around 6000 nuclei within the syncytium in a crystalline-like order, it is unclear what processes dominate aster dynamics. Here, we take advantage of a cell cycle regulation Drosophila mutant to generate embryos with multiple asters, independent from nuclei. We use an ex vivo assay to further simplify this biological system to explore the forces generated by and between asters. Through live imaging, drug and optical perturbations, and theoretical modeling, we demonstrate that these asters likely generate an effective pushing force over short distances.
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Affiliation(s)
- Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
| | - Sham Tlili
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
| | - Timothy E Saunders
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Institute of Molecular and Cellular Biology, A*Star, ProteosSingaporeSingapore
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of WarwickWarwickUnited Kingdom
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
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Milas A, de-Carvalho J, Telley IA. Follicle cell contact maintains main body axis polarity in the Drosophila melanogaster oocyte. J Cell Biol 2022; 222:213703. [PMID: 36409222 PMCID: PMC9682419 DOI: 10.1083/jcb.202209052] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/23/2022] Open
Abstract
In Drosophila melanogaster, the anterior-posterior body axis is maternally established and governed by differential localization of partitioning defective (Par) proteins within the oocyte. At mid-oogenesis, Par-1 accumulates at the oocyte posterior end, while Par-3/Bazooka is excluded there but maintains its localization along the remaining oocyte cortex. Past studies have proposed the need for somatic cells at the posterior end to initiate oocyte polarization by providing a trigger signal. To date, neither the molecular identity nor the nature of the signal is known. Here, we provide evidence that mechanical contact of posterior follicle cells (PFCs) with the oocyte cortex causes the posterior exclusion of Bazooka and maintains oocyte polarity. We show that Bazooka prematurely accumulates exclusively where posterior follicle cells have been mechanically detached or ablated. Furthermore, we provide evidence that PFC contact maintains Par-1 and oskar mRNA localization and microtubule cytoskeleton polarity in the oocyte. Our observations suggest that cell-cell contact mechanics modulates Par protein binding sites at the oocyte cortex.
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Affiliation(s)
- Ana Milas
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Ivo A. Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal,Correspondence to Ivo A. Telley:
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de-Carvalho J, Tlili S, Hufnagel L, Saunders TE, Telley IA. Aster repulsion drives short-ranged ordering in the Drosophila syncytial blastoderm. Development 2022; 149:274085. [DOI: 10.1242/dev.199997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 12/17/2021] [Indexed: 12/28/2022]
Abstract
ABSTRACT
Biological systems are highly complex, yet notably ordered structures can emerge. During syncytial stage development of the Drosophila melanogaster embryo, nuclei synchronously divide for nine cycles within a single cell, after which most of the nuclei reach the cell cortex. The arrival of nuclei at the cortex occurs with remarkable positional order, which is important for subsequent cellularisation and morphological transformations. Yet, the mechanical principles underlying this lattice-like positional order of nuclei remain untested. Here, using quantification of nuclei position and division orientation together with embryo explants, we show that short-ranged repulsive interactions between microtubule asters ensure the regular distribution and maintenance of nuclear positions in the embryo. Such ordered nuclear positioning still occurs with the loss of actin caps and even the loss of the nuclei themselves; the asters can self-organise with similar distribution to nuclei in the wild-type embryo. The explant assay enabled us to deduce the nature of the mechanical interaction between pairs of nuclei. We used this to predict how the nuclear division axis orientation changes upon nucleus removal from the embryo cortex, which we confirmed in vivo with laser ablation. Overall, we show that short-ranged microtubule-mediated repulsive interactions between asters are important for ordering in the early Drosophila embryo and minimising positional irregularity.
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Affiliation(s)
- Jorge de-Carvalho
- Physics of Intracellular Organization Group, Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Sham Tlili
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
| | - Lars Hufnagel
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Timothy E. Saunders
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
- Department of Biological Sciences, National University of Singapore, 117411Singapore
- Institute of Molecular and Cellular Biology, A*Star, Proteos, 138632 Singapore
- Warwick Medical School, University of Warwick, Coventry, CV4 7HL, UK
| | - Ivo A. Telley
- Physics of Intracellular Organization Group, Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
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Deshpande O, de-Carvalho J, Vieira DV, Telley IA. Astral microtubule cross-linking safeguards uniform nuclear distribution in the Drosophila syncytium. J Cell Biol 2022; 221:212810. [PMID: 34766978 PMCID: PMC8594625 DOI: 10.1083/jcb.202007209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/24/2021] [Accepted: 10/20/2021] [Indexed: 12/16/2022] Open
Abstract
The early insect embryo develops as a multinucleated cell distributing the genome uniformly to the cell cortex. Mechanistic insight for nuclear positioning beyond cytoskeletal requirements is missing. Contemporary hypotheses propose actomyosin-driven cytoplasmic movement transporting nuclei or repulsion of neighbor nuclei driven by microtubule motors. Here, we show that microtubule cross-linking by Feo and Klp3A is essential for nuclear distribution and internuclear distance maintenance in Drosophila. Germline knockdown causes irregular, less-dense nuclear delivery to the cell cortex and smaller distribution in ex vivo embryo explants. A minimal internuclear distance is maintained in explants from control embryos but not from Feo-inhibited embryos, following micromanipulation-assisted repositioning. A dimerization-deficient Feo abolishes nuclear separation in embryo explants, while the full-length protein rescues the genetic knockdown. We conclude that Feo and Klp3A cross-linking of antiparallel microtubule overlap generates a length-regulated mechanical link between neighboring microtubule asters. Enabled by a novel experimental approach, our study illuminates an essential process of embryonic multicellularity.
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Affiliation(s)
- Ojas Deshpande
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Diana V Vieira
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Oeiras, Portugal
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Nabais C, Pessoa D, de-Carvalho J, van Zanten T, Duarte P, Mayor S, Carneiro J, Telley IA, Bettencourt-Dias M. Plk4 triggers autonomous de novo centriole biogenesis and maturation. J Cell Biol 2021; 220:211915. [PMID: 33760919 PMCID: PMC7995200 DOI: 10.1083/jcb.202008090] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/14/2020] [Accepted: 02/18/2021] [Indexed: 12/23/2022] Open
Abstract
Centrioles form centrosomes and cilia. In most proliferating cells, centrioles assemble through canonical duplication, which is spatially, temporally, and numerically regulated by the cell cycle and the presence of mature centrioles. However, in certain cell types, centrioles assemble de novo, yet by poorly understood mechanisms. Herein, we established a controlled system to investigate de novo centriole biogenesis, using Drosophila melanogaster egg explants overexpressing Polo-like kinase 4 (Plk4), a trigger for centriole biogenesis. We show that at a high Plk4 concentration, centrioles form de novo, mature, and duplicate, independently of cell cycle progression and of the presence of other centrioles. Plk4 concentration determines the temporal onset of centriole assembly. Moreover, our results suggest that distinct biochemical kinetics regulate de novo and canonical biogenesis. Finally, we investigated which other factors modulate de novo centriole assembly and found that proteins of the pericentriolar material (PCM), and in particular γ-tubulin, promote biogenesis, likely by locally concentrating critical components.
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Affiliation(s)
| | | | | | | | - Paulo Duarte
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Satyajit Mayor
- National Centre for Biological Sciences, Bangalore, India
| | | | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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Abstract
Cell and tissue functions rely on the genetic programmes and cascades of biochemical signals. It has become evident during the past decade that the physical properties of soft material that govern the mechanics of cells and tissues play an important role in cellular function and morphology. The biophysical properties of cells and tissues are determined by the cytoskeleton, consisting of dynamic networks of F-actin and microtubules, molecular motors, crosslinkers and other associated proteins, among other factors such as cell-cell interactions. The Drosophila syncytial embryo represents a simple pseudo-tissue, with its nuclei orderly embedded in a structured cytoskeletal matrix at the embryonic cortex with no physical separation by cellular membranes. Here, we review the stereotypic dynamics and regulation of the cytoskeleton in Drosophila syncytial embryos and how cytoskeletal dynamics underlies biophysical properties and the emergence of collective features. We highlight the specific features and processes of syncytial embryos and discuss the applicability of biophysical approaches.
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Affiliation(s)
- Zhiyi Lv
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, 2780-156 Oeiras, Portugal
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, 2780-156 Oeiras, Portugal
| | - Jörg Großhans
- Fachbereich Biologie, Philipps-Universität Marburg, 35043 Marburg, Germany
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de-Carvalho J, Deshpande O, Nabais C, Telley IA. A cell-free system of Drosophila egg explants supporting native mitotic cycles. Methods Cell Biol 2018; 144:233-257. [DOI: 10.1016/bs.mcb.2018.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Rodrigues RMM, de-Carvalho J, Henriques SF, Mira NP, Sá-Correia I, Ferreira GNM. Transmission line model analysis of transcription factors binding to oligoduplexes - differentiation of the effect of single nucleotide modifications. Analyst 2015; 139:3871-4. [PMID: 24955439 DOI: 10.1039/c4an00709c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advanced impedance spectroscopy analysis based on the transmission line model (TLM) is explored as a novel QCM acoustic biosensing platform for the detection of the single point mutation effect on the binding of the transcription factors (TFs) to immobilized DNA oligoduplexes and the characterization of the protein-DNA mechanical properties.
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Affiliation(s)
- Rogério M M Rodrigues
- IBB-Institute for Biotechnology and Bioengineering, Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, 8005-139 Faro, Portugal.
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de-Carvalho J, Rodrigues RMM, Tomé B, Henriques SF, Mira NP, Sá-Correia I, Ferreira GNM. Conformational and mechanical changes of DNA upon transcription factor binding detected by a QCM and transmission line model. Analyst 2015; 139:1847-55. [PMID: 24352369 DOI: 10.1039/c3an01682j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel quartz crystal microbalance (QCM) analytical method is developed based on the transmission line model (TLM) algorithm to analyze the binding of transcription factors (TFs) to immobilized DNA oligoduplexes. The method is used to characterize the mechanical properties of biological films through the estimation of the film dynamic shear moduli, G and G, and the film thickness. Using the Saccharomyces cerevisiae transcription factor Haa1 (Haa1DBD) as a biological model two sensors were prepared by immobilizing DNA oligoduplexes, one containing the Haa1 recognition element (HRE(wt)) and another with a random sequence (HRE(neg)) used as a negative control. The immobilization of DNA oligoduplexes was followed in real time and we show that DNA strands initially adsorb with low or non-tilting, laying flat close to the surface, which then lift-off the surface leading to final film tilting angles of 62.9° and 46.7° for HRE(wt) and HRE(neg), respectively. Furthermore we show that the binding of Haa1DBD to HRE(wt) leads to a more ordered and compact film, and forces a 31.7° bending of the immobilized HRE(wt) oligoduplex. This work demonstrates the suitability of the QCM to monitor the specific binding of TFs to immobilized DNA sequences and provides an analytical methodology to study protein-DNA biophysics and kinetics.
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Affiliation(s)
- Jorge de-Carvalho
- IBB-Institute for Biotechnology and Bioengineering, Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, 8005-139 Faro, Portugal.
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Rodrigues RMM, de-Carvalho J, Ferreira GNM. Kinetic characterization of the retinoic X receptor binding to specific and unspecific DNA oligoduplexes with a quartz crystal microbalance. Analyst 2014; 139:3434-40. [PMID: 24824382 DOI: 10.1039/c4an00286e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quartz Crystal Microbalance (QCM) biosensor technology was used to study the interaction of the DNA-binding domain (DBD) of the transcription factor RXRα with immobilized specific (DR1) and unspecific (DR1neg) DNA oligoduplexes. We identify the QCM sensor frequency at the susceptance minimum (fBmin) as a better measuring parameter, and we show that fBmin is proportional to the mass adsorbed at the sensor surface and is not influenced by interferences coming from viscoelastic variations of the adsorbed layers or buffers. This parameter was used to study the binding of RXRα to DNA and to calculate the association and dissociation kinetic constants of RXRαDBD-DR1 interaction. We show that RXRαDBD binds to DNA both as a monomer and as a homodimer, and that the mechanism of binding is salt dependent and occurs in two steps. The QCM biosensor data reveal that a high ionic strength buffer prevents the unspecific interactions and at a lower ionic strength the dissociation of RXRαDBD-DR1 occurs in two phases.
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Affiliation(s)
- Rogério M M Rodrigues
- IBB-Institute for Biotechnology and Bioengineering, Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, 8005-139 Faro, Portugal.
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Da-Silva AC, Rodrigues R, Rosa LFM, de-Carvalho J, Tomé B, Ferreira GNM. Acoustic detection of cell adhesion on a quartz crystal microbalance. Biotechnol Appl Biochem 2012; 59:411-9. [DOI: 10.1002/bab.1041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 08/19/2012] [Indexed: 01/18/2023]
Affiliation(s)
- Ana-Carina Da-Silva
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
| | - Rogério Rodrigues
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
| | - Luís F. M. Rosa
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
| | - Jorge de-Carvalho
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
| | - Brigitte Tomé
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
| | - Guilherme N. M. Ferreira
- IBB-Institute for Biotechnology and Bioengineering, Centre for Molecular and Structural Biomedicine, University of the Algarve; Campus de Gambelas; Faro; Portugal
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