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Miao Y, Pourquié O. Cellular and molecular control of vertebrate somitogenesis. Nat Rev Mol Cell Biol 2024; 25:517-533. [PMID: 38418851 DOI: 10.1038/s41580-024-00709-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 03/02/2024]
Abstract
Segmentation is a fundamental feature of the vertebrate body plan. This metameric organization is first implemented by somitogenesis in the early embryo, when paired epithelial blocks called somites are rhythmically formed to flank the neural tube. Recent advances in in vitro models have offered new opportunities to elucidate the mechanisms that underlie somitogenesis. Notably, models derived from human pluripotent stem cells introduced an efficient proxy for studying this process during human development. In this Review, we summarize the current understanding of somitogenesis gained from both in vivo studies and in vitro studies. We deconstruct the spatiotemporal dynamics of somitogenesis into four distinct modules: dynamic events in the presomitic mesoderm, segmental determination, somite anteroposterior polarity patterning, and epithelial morphogenesis. We first focus on the segmentation clock, as well as signalling and metabolic gradients along the tissue, before discussing the clock and wavefront and other models that account for segmental determination. We then detail the molecular and cellular mechanisms of anteroposterior polarity patterning and somite epithelialization.
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Affiliation(s)
- Yuchuan Miao
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA.
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
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2
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Miao Y. In preprints: tick, tick, somite - an intrinsic timer regulates segmentation. Development 2024; 151:dev202686. [PMID: 38293868 DOI: 10.1242/dev.202686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Affiliation(s)
- Yuchuan Miao
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
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3
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Ramesh PS, Chu LF. Species-specific roles of the Notch ligands, receptors, and targets orchestrating the signaling landscape of the segmentation clock. Front Cell Dev Biol 2024; 11:1327227. [PMID: 38348091 PMCID: PMC10859470 DOI: 10.3389/fcell.2023.1327227] [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: 10/24/2023] [Accepted: 12/20/2023] [Indexed: 02/15/2024] Open
Abstract
Somitogenesis is a hallmark feature of all vertebrates and some invertebrate species that involves the periodic formation of block-like structures called somites. Somites are transient embryonic segments that eventually establish the entire vertebral column. A highly conserved molecular oscillator called the segmentation clock underlies this periodic event and the pace of this clock regulates the pace of somite formation. Although conserved signaling pathways govern the clock in most vertebrates, the mechanisms underlying the species-specific divergence in various clock characteristics remain elusive. For example, the segmentation clock in classical model species such as zebrafish, chick, and mouse embryos tick with a periodicity of ∼30, ∼90, and ∼120 min respectively. This enables them to form the species-specific number of vertebrae during their overall timespan of somitogenesis. Here, we perform a systematic review of the species-specific features of the segmentation clock with a keen focus on mouse embryos. We perform this review using three different perspectives: Notch-responsive clock genes, ligand-receptor dynamics, and synchronization between neighboring oscillators. We further review reports that use non-classical model organisms and in vitro model systems that complement our current understanding of the segmentation clock. Our review highlights the importance of comparative developmental biology to further our understanding of this essential developmental process.
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Affiliation(s)
- Pranav S. Ramesh
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
- Reproductive Biology and Regenerative Medicine Research Group, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, Calgary, AB, Canada
| | - Li-Fang Chu
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
- Reproductive Biology and Regenerative Medicine Research Group, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, Calgary, AB, Canada
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4
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Loureiro C, Venzin OF, Oates AC. Generation of patterns in the paraxial mesoderm. Curr Top Dev Biol 2023; 159:372-405. [PMID: 38729682 DOI: 10.1016/bs.ctdb.2023.11.001] [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] [Indexed: 05/12/2024]
Abstract
The Segmentation Clock is a tissue-level patterning system that enables the segmentation of the vertebral column precursors into transient multicellular blocks called somites. This patterning system comprises a set of elements that are essential for correct segmentation. Under the so-called "Clock and Wavefront" model, the system consists of two elements, a genetic oscillator that manifests itself as traveling waves of gene expression, and a regressing wavefront that transforms the temporally periodic signal encoded in the oscillations into a permanent spatially periodic pattern of somite boundaries. Over the last twenty years, every new discovery about the Segmentation Clock has been tightly linked to the nomenclature of the "Clock and Wavefront" model. This constrained allocation of discoveries into these two elements has generated long-standing debates in the field as what defines molecularly the wavefront and how and where the interaction between the two elements establishes the future somite boundaries. In this review, we propose an expansion of the "Clock and Wavefront" model into three elements, "Clock", "Wavefront" and signaling gradients. We first provide a detailed description of the components and regulatory mechanisms of each element, and we then examine how the spatiotemporal integration of the three elements leads to the establishment of the presumptive somite boundaries. To be as exhaustive as possible, we focus on the Segmentation Clock in zebrafish. Furthermore, we show how this three-element expansion of the model provides a better understanding of the somite formation process and we emphasize where our current understanding of this patterning system remains obscure.
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Affiliation(s)
- Cristina Loureiro
- Institute of Bioengineering, School of Life Sciences, Swiss Federal Institute of Technology Lausanne EPFL, Switzerland
| | - Olivier F Venzin
- Institute of Bioengineering, School of Life Sciences, Swiss Federal Institute of Technology Lausanne EPFL, Switzerland
| | - Andrew C Oates
- Institute of Bioengineering, School of Life Sciences, Swiss Federal Institute of Technology Lausanne EPFL, Switzerland.
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5
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Yabe T, Uriu K, Takada S. Ripply suppresses Tbx6 to induce dynamic-to-static conversion in somite segmentation. Nat Commun 2023; 14:2115. [PMID: 37055428 PMCID: PMC10102234 DOI: 10.1038/s41467-023-37745-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 03/29/2023] [Indexed: 04/15/2023] Open
Abstract
The metameric pattern of somites is created based on oscillatory expression of clock genes in presomitic mesoderm. However, the mechanism for converting the dynamic oscillation to a static pattern of somites is still unclear. Here, we provide evidence that Ripply/Tbx6 machinery is a key regulator of this conversion. Ripply1/Ripply2-mediated removal of Tbx6 protein defines somite boundary and also leads to cessation of clock gene expression in zebrafish embryos. On the other hand, activation of ripply1/ripply2 mRNA and protein expression is periodically regulated by clock oscillation in conjunction with an Erk signaling gradient. Whereas Ripply protein decreases rapidly in embryos, Ripply-triggered Tbx6 suppression persists long enough to complete somite boundary formation. Mathematical modeling shows that a molecular network based on results of this study can reproduce dynamic-to-static conversion in somitogenesis. Furthermore, simulations with this model suggest that sustained suppression of Tbx6 caused by Ripply is crucial in this conversion.
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Affiliation(s)
- Taijiro Yabe
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
- National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
- The Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
| | - Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
| | - Shinji Takada
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
- National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
- The Graduate University for Advanced Studies (SOKENDAI), 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
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6
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Uriu K, Morelli LG. Orchestration of tissue shape changes and gene expression patterns in development. Semin Cell Dev Biol 2023; 147:24-33. [PMID: 36631335 DOI: 10.1016/j.semcdb.2022.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/27/2022] [Accepted: 12/27/2022] [Indexed: 01/11/2023]
Abstract
In development, tissue shape changes and gene expression patterns give rise to morphogenesis. Understanding tissue shape changes requires the analysis of mechanical properties of the tissue such as tissue rigidity, cell influx from neighboring tissues, cell shape changes and cell proliferation. Local and global gene expression patterns can be influenced by neighbor exchange and tissue shape changes. Here we review recent studies on the mechanisms for tissue elongation and its influences on dynamic gene expression patterns by focusing on vertebrate somitogenesis. We first introduce mechanical and biochemical properties of the segmenting tissue that drive tissue elongation. Then, we discuss patterning in the presence of cell mixing, scaling of signaling gradients, and dynamic phase waves of rhythmic gene expression under tissue shape changes. We also highlight the importance of theoretical approaches to address the relation between tissue shape changes and patterning.
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Affiliation(s)
- Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 Japan.
| | - Luis G Morelli
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Polo Científico Tecnológico, Godoy Cruz 2390, C1425FQD, Buenos Aires, Argentina; Departamento de Física, FCEyN UBA, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
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7
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Blatnik MC, Gallagher TL, Amacher SL. Keeping development on time: Insights into post-transcriptional mechanisms driving oscillatory gene expression during vertebrate segmentation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1751. [PMID: 35851751 PMCID: PMC9840655 DOI: 10.1002/wrna.1751] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/13/2022] [Accepted: 06/20/2022] [Indexed: 01/31/2023]
Abstract
Biological time keeping, or the duration and tempo at which biological processes occur, is a phenomenon that drives dynamic molecular and morphological changes that manifest throughout many facets of life. In some cases, the molecular mechanisms regulating the timing of biological transitions are driven by genetic oscillations, or periodic increases and decreases in expression of genes described collectively as a "molecular clock." In vertebrate animals, molecular clocks play a crucial role in fundamental patterning and cell differentiation processes throughout development. For example, during early vertebrate embryogenesis, the segmentation clock regulates the patterning of the embryonic mesoderm into segmented blocks of tissue called somites, which later give rise to axial skeletal muscle and vertebrae. Segmentation clock oscillations are characterized by rapid cycles of mRNA and protein expression. For segmentation clock oscillations to persist, the transcript and protein molecules of clock genes must be short-lived. Faithful, rhythmic, genetic oscillations are sustained by precise regulation at many levels, including post-transcriptional regulation, and such mechanisms are essential for proper vertebrate development. This article is categorized under: RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability Translation > Regulation.
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Affiliation(s)
- Monica C. Blatnik
- The Ohio State University, Department of Molecular Genetics, Columbus, Ohio, 43210-1132, United States
| | - Thomas L. Gallagher
- The Ohio State University, Department of Molecular Genetics, Columbus, Ohio, 43210-1132, United States
| | - Sharon L. Amacher
- The Ohio State University, Department of Molecular Genetics, Columbus, Ohio, 43210-1132, United States
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8
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Carraco G, Martins-Jesus AP, Andrade RP. The vertebrate Embryo Clock: Common players dancing to a different beat. Front Cell Dev Biol 2022; 10:944016. [PMID: 36036002 PMCID: PMC9403190 DOI: 10.3389/fcell.2022.944016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022] Open
Abstract
Vertebrate embryo somitogenesis is the earliest morphological manifestation of the characteristic patterned structure of the adult axial skeleton. Pairs of somites flanking the neural tube are formed periodically during early development, and the molecular mechanisms in temporal control of this early patterning event have been thoroughly studied. The discovery of a molecular Embryo Clock (EC) underlying the periodicity of somite formation shed light on the importance of gene expression dynamics for pattern formation. The EC is now known to be present in all vertebrate organisms studied and this mechanism was also described in limb development and stem cell differentiation. An outstanding question, however, remains unanswered: what sets the different EC paces observed in different organisms and tissues? This review aims to summarize the available knowledge regarding the pace of the EC, its regulation and experimental manipulation and to expose new questions that might help shed light on what is still to unveil.
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Affiliation(s)
- Gil Carraco
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas (FMCB), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| | | | - Raquel P. Andrade
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas (FMCB), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal
- *Correspondence: Raquel P. Andrade,
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9
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Falk HJ, Tomita T, Mönke G, McDole K, Aulehla A. Imaging the onset of oscillatory signaling dynamics during mouse embryo gastrulation. Development 2022; 149:275659. [PMID: 35686648 PMCID: PMC9340547 DOI: 10.1242/dev.200083] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 05/25/2022] [Indexed: 01/24/2023]
Abstract
A fundamental requirement for embryonic development is the coordination of signaling activities in space and time. A notable example in vertebrate embryos is found during somitogenesis, where gene expression oscillations linked to the segmentation clock are synchronized across cells in the presomitic mesoderm (PSM) and result in tissue-level wave patterns. To examine their onset during mouse embryo development, we studied the dynamics of the segmentation clock gene Lfng during gastrulation. To this end, we established an imaging setup using selective plane illumination microscopy (SPIM) that enables culture and simultaneous imaging of up to four embryos (‘SPIM- for-4’). Using SPIM-for-4, combined with genetically encoded signaling reporters, we detected the onset of Lfng oscillations within newly formed mesoderm at presomite stages. Functionally, we found that initial synchrony and the first ∼6-8 oscillation cycles occurred even when Notch signaling was impaired, revealing similarities to previous findings made in zebrafish embryos. Finally, we show that a spatial period gradient is present at the onset of oscillatory activity, providing a potential mechanism accounting for our observation that wave patterns build up gradually over the first oscillation cycles. Summary: A versatile light-sheet imaging setup enabling simultaneous live imaging of multiple mouse embryos for 48 h, an approach that offers insight into the onset of oscillatory signaling dynamics and the segmentation clock.
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Affiliation(s)
- Henning J Falk
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Takehito Tomita
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gregor Mönke
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Katie McDole
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Alexander Aulehla
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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10
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Abstract
Embryonic development hinges on effective coordination of molecular events across space and time. Waves have recently emerged as constituting an ubiquitous mechanism that ensures rapid spreading of regulatory signals across embryos, as well as reliable control of their patterning, namely, for the emergence of body plan structures. In this article, we review a selection of recent quantitative work on signaling waves and present an overview of the theory of waves. Our aim is to provide a succinct yet comprehensive guiding reference for the theoretical frameworks by which signaling waves can arise in embryos. We start, then, from reaction-diffusion systems, both static and time dependent; move to excitable dynamics; and conclude with systems of coupled oscillators. We link these theoretical models to molecular mechanisms recently elucidated for the control of mitotic waves in early embryos, patterning of the vertebrate body axis, micropattern cultures, and bone regeneration. Our goal is to inspire experimental work that will advance theory in development and connect its predictions to quantitative biological observations. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Massimo Vergassola
- Laboratoire de physique de l'École Normale Supérieure, CNRS, PSL Research University, Sorbonne Université, Paris, France; .,Department of Physics, University of California, San Diego, California, USA
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11
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Duarte I, Carraco G, de Azevedo NTD, Benes V, Andrade RP. gga-miRNOME, a microRNA-sequencing dataset from chick embryonic tissues. Sci Data 2022; 9:29. [PMID: 35102184 PMCID: PMC8803849 DOI: 10.1038/s41597-022-01126-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/15/2021] [Indexed: 11/08/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNA molecules, with sizes ranging from 18 to 25 nucleotides, which are key players in gene expression regulation. These molecules play an important role in fine-tuning early vertebrate embryo development. However, there are scarce publicly available miRNA datasets from non-mammal embryos, such as the chicken (Gallus gallus), which is a classical model system to study vertebrate embryogenesis. Here, we performed microRNA-sequencing to characterize the early stages of trunk and limb development in the chick embryo. For this, we profiled three chick embryonic tissues, namely, Undetermined Presomitic Mesoderm (PSM_U), Determined Presomitic Mesoderm (PSM_D) and Forelimb Distal Cyclic Domain (DCD). We identified 926 known miRNAs, and 1,141 novel candidate miRNAs, which nearly duplicates the number of Gallus gallus entries in the miRBase database. These data will greatly benefit the avian research community, particularly by highlighting new miRNAs potentially involved in the regulation of early vertebrate embryo development, that can be prioritized for further experimental testing.
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Affiliation(s)
- Isabel Duarte
- Faculdade de Medicina e Ciências Biomédicas (FMCB), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
- Center for Health Technology and Services Research (CINTESIS), Polo da Universidade do Algarve, 8005-139, Faro, Portugal
| | - Gil Carraco
- Faculdade de Medicina e Ciências Biomédicas (FMCB), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
- ProRegeM-PhD Program in Mechanisms of Disease and Regenerative Medicine, Faro, Portugal
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal
| | | | | | - Raquel P Andrade
- Faculdade de Medicina e Ciências Biomédicas (FMCB), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal.
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal.
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12
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Chou KT, Lee DYD, Chiou JG, Galera-Laporta L, Ly S, Garcia-Ojalvo J, Süel GM. A segmentation clock patterns cellular differentiation in a bacterial biofilm. Cell 2022; 185:145-157.e13. [PMID: 34995513 PMCID: PMC8754390 DOI: 10.1016/j.cell.2021.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/13/2021] [Accepted: 11/30/2021] [Indexed: 01/09/2023]
Abstract
Contrary to multicellular organisms that display segmentation during development, communities of unicellular organisms are believed to be devoid of such sophisticated patterning. Unexpectedly, we find that the gene expression underlying the nitrogen stress response of a developing Bacillus subtilis biofilm becomes organized into a ring-like pattern. Mathematical modeling and genetic probing of the underlying circuit indicate that this patterning is generated by a clock and wavefront mechanism, similar to that driving vertebrate somitogenesis. We experimentally validated this hypothesis by showing that predicted nutrient conditions can even lead to multiple concentric rings, resembling segments. We additionally confirmed that this patterning mechanism is driven by cell-autonomous oscillations. Importantly, we show that the clock and wavefront process also spatially patterns sporulation within the biofilm. Together, these findings reveal a biofilm segmentation clock that organizes cellular differentiation in space and time, thereby challenging the paradigm that such patterning mechanisms are exclusive to plant and animal development.
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Affiliation(s)
- Kwang-Tao Chou
- Molecular Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Dong-Yeon D Lee
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Jian-Geng Chiou
- Molecular Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Leticia Galera-Laporta
- Molecular Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - San Ly
- Molecular Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jordi Garcia-Ojalvo
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Gürol M Süel
- Molecular Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; San Diego Center for Systems Biology, University of California San Diego, La Jolla, CA 92093-0380, USA; Center for Microbiome Innovation, University of California San Diego, La Jolla, CA 92093-0380, USA.
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13
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Linde-Medina M, Smit TH. Molecular and Mechanical Cues for Somite Periodicity. Front Cell Dev Biol 2021; 9:753446. [PMID: 34901002 PMCID: PMC8663771 DOI: 10.3389/fcell.2021.753446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
Somitogenesis refers to the segmentation of the paraxial mesoderm, a tissue located on the back of the embryo, into regularly spaced and sized pieces, i.e., the somites. This periodicity is important to assure, for example, the formation of a functional vertebral column. Prevailing models of somitogenesis are based on the existence of a gene regulatory network capable of generating a striped pattern of gene expression, which is subsequently translated into periodic tissue boundaries. An alternative view is that the pre-pattern that guides somitogenesis is not chemical, but of a mechanical origin. A striped pattern of mechanical strain can be formed in physically connected tissues expanding at different rates, as it occurs in the embryo. Here we argue that both molecular and mechanical cues could drive somite periodicity and suggest how they could be integrated.
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Affiliation(s)
| | - Theodoor H. Smit
- Department of Orthopaedic Surgery, Amsterdam Movement Sciences, Amsterdam University Medical Centres, Amsterdam, Netherlands
- Department of Medical Biology, Amsterdam University Medical Centres, Amsterdam, Netherlands
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14
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Kuyyamudi C, Menon SN, Sinha S. Morphogen-regulated contact-mediated signaling between cells can drive the transitions underlying body segmentation in vertebrates. Phys Biol 2021; 19. [PMID: 34670199 DOI: 10.1088/1478-3975/ac31a3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/20/2021] [Indexed: 11/12/2022]
Abstract
We propose a unified mechanism that reproduces the sequence of dynamical transitions observed during somitogenesis, the process of body segmentation during embryonic development, that is invariant across all vertebrate species. This is achieved by combining inter-cellular interactions mediated via receptor-ligand coupling with global spatial heterogeneity introduced through a morphogen gradient known to occur along the anteroposterior axis. Our model reproduces synchronized oscillations in the gene expression in cells at the anterior of the presomitic mesoderm as it grows by adding new cells at its posterior, followed by travelling waves and subsequent arrest of activity, with the eventual appearance of somite-like patterns. This framework integrates a boundary-organized pattern formation mechanism, which uses positional information provided by a morphogen gradient, with the coupling-mediated self-organized emergence of collective dynamics, to explain the processes that lead to segmentation.
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Affiliation(s)
- Chandrashekar Kuyyamudi
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, India
| | - Shakti N Menon
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113, India
| | - Sitabhra Sinha
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, India
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15
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Diaz-Cuadros M, Pourquié O, El-Sherif E. Patterning with clocks and genetic cascades: Segmentation and regionalization of vertebrate versus insect body plans. PLoS Genet 2021; 17:e1009812. [PMID: 34648490 PMCID: PMC8516289 DOI: 10.1371/journal.pgen.1009812] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Oscillatory and sequential processes have been implicated in the spatial patterning of many embryonic tissues. For example, molecular clocks delimit segmental boundaries in vertebrates and insects and mediate lateral root formation in plants, whereas sequential gene activities are involved in the specification of regional identities of insect neuroblasts, vertebrate neural tube, vertebrate limb, and insect and vertebrate body axes. These processes take place in various tissues and organisms, and, hence, raise the question of what common themes and strategies they share. In this article, we review 2 processes that rely on the spatial regulation of periodic and sequential gene activities: segmentation and regionalization of the anterior-posterior (AP) axis of animal body plans. We study these processes in species that belong to 2 different phyla: vertebrates and insects. By contrasting 2 different processes (segmentation and regionalization) in species that belong to 2 distantly related phyla (arthropods and vertebrates), we elucidate the deep logic of patterning by oscillatory and sequential gene activities. Furthermore, in some of these organisms (e.g., the fruit fly Drosophila), a mode of AP patterning has evolved that seems not to overtly rely on oscillations or sequential gene activities, providing an opportunity to study the evolution of pattern formation mechanisms.
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Affiliation(s)
- Margarete Diaz-Cuadros
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ezzat El-Sherif
- Division of Developmental Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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16
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Boareto M, Tomka T, Iber D. Positional information encoded in the dynamic differences between neighboring oscillators during vertebrate segmentation. Cells Dev 2021; 168:203737. [PMID: 34481980 DOI: 10.1016/j.cdev.2021.203737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/28/2021] [Accepted: 08/20/2021] [Indexed: 01/24/2023]
Abstract
A central problem in developmental biology is to understand how cells interpret their positional information to give rise to spatial patterns, such as the process of periodic segmentation of the vertebrate embryo into somites. For decades, somite formation has been interpreted according to the clock-and-wavefront model. In this conceptual framework, molecular oscillators set the frequency of somite formation while the positional information is encoded in signaling gradients. Recent experiments using ex vivo explants have challenged this interpretation, suggesting that positional information is encoded in the properties of the oscillators, independent of long-range modulations such as signaling gradients. Here, we propose that positional information is encoded in the difference in the levels of neighboring oscillators. The differences gradually increase because both the amplitude and the period of the oscillators increase with time. When this difference exceeds a certain threshold, the segmentation program starts. Using this framework, we quantitatively fit experimental data from in vivo and ex vivo mouse segmentation, and propose mechanisms of somite scaling. Our results suggest a novel mechanism of spatial pattern formation based on the local interactions between dynamic molecular oscillators.
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Affiliation(s)
- Marcelo Boareto
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Tomas Tomka
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Dagmar Iber
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, Mattenstrasse 26, 4058 Basel, Switzerland.
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17
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Abstract
The temporal coordination of events at cellular and tissue scales is essential for the proper development of organisms, and involves cell-intrinsic processes that can be coupled by local cellular signalling and instructed by global signalling, thereby creating spatial patterns of cellular states that change over time. The timing and structure of these patterns determine how an organism develops. Traditional developmental genetic methods have revealed the complex molecular circuits regulating these processes but are limited in their ability to predict and understand the emergent spatio-temporal dynamics. Increasingly, approaches from physics are now being used to help capture the dynamics of the system by providing simplified, generic descriptions. Combined with advances in imaging and computational power, such approaches aim to provide insight into timing and patterning in developing systems.
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18
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Abstract
Arthropod segmentation and vertebrate somitogenesis are leading fields in the experimental and theoretical interrogation of developmental patterning. However, despite the sophistication of current research, basic conceptual issues remain unresolved. These include: (i) the mechanistic origins of spatial organization within the segment addition zone (SAZ); (ii) the mechanistic origins of segment polarization; (iii) the mechanistic origins of axial variation; and (iv) the evolutionary origins of simultaneous patterning. Here, I explore these problems using coarse-grained models of cross-regulating dynamical processes. In the morphogenetic framework of a row of cells undergoing axial elongation, I simulate interactions between an 'oscillator', a 'switch' and up to three 'timers', successfully reproducing essential patterning behaviours of segmenting systems. By comparing the output of these largely cell-autonomous models to variants that incorporate positional information, I find that scaling relationships, wave patterns and patterning dynamics all depend on whether the SAZ is regulated by temporal or spatial information. I also identify three mechanisms for polarizing oscillator output, all of which functionally implicate the oscillator frequency profile. Finally, I demonstrate significant dynamical and regulatory continuity between sequential and simultaneous modes of segmentation. I discuss these results in the context of the experimental literature.
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Affiliation(s)
- Erik Clark
- Department of Systems Biology, Harvard Medical School, 210 Longwood Ave, Boston, MA 02115, USA
- Trinity College Cambridge, University of Cambridge, Trinity Street, Cambridge CB2 1TQ, UK
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19
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Uriu K, Liao BK, Oates AC, Morelli LG. From local resynchronization to global pattern recovery in the zebrafish segmentation clock. eLife 2021; 10:61358. [PMID: 33587039 PMCID: PMC7984840 DOI: 10.7554/elife.61358] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/27/2021] [Indexed: 01/26/2023] Open
Abstract
Integrity of rhythmic spatial gene expression patterns in the vertebrate segmentation clock requires local synchronization between neighboring cells by Delta-Notch signaling and its inhibition causes defective segment boundaries. Whether deformation of the oscillating tissue complements local synchronization during patterning and segment formation is not understood. We combine theory and experiment to investigate this question in the zebrafish segmentation clock. We remove a Notch inhibitor, allowing resynchronization, and analyze embryonic segment recovery. We observe unexpected intermingling of normal and defective segments, and capture this with a new model combining coupled oscillators and tissue mechanics. Intermingled segments are explained in the theory by advection of persistent phase vortices of oscillators. Experimentally observed changes in recovery patterns are predicted in the theory by temporal changes in tissue length and cell advection pattern. Thus, segmental pattern recovery occurs at two length and time scales: rapid local synchronization between neighboring cells, and the slower transport of the resulting patterns across the tissue through morphogenesis.
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Affiliation(s)
- Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - Bo-Kai Liao
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan.,Department of Cell and Developmental Biology, University College London, Gower Street, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Andrew C Oates
- Department of Cell and Developmental Biology, University College London, Gower Street, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Institute of Bioengineering, École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Luis G Morelli
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Polo Científico Tecnológico, Buenos Aires, Argentina.,Departamento de Física, FCEyN UBA, Ciudad Universitaria, Buenos Aires, Argentina.,Max Planck Institute for Molecular Physiology, Department of Systemic Cell Biology, Dortmund, Germany
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20
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Jutras-Dubé L, El-Sherif E, François P. Geometric models for robust encoding of dynamical information into embryonic patterns. eLife 2020; 9:55778. [PMID: 32773041 PMCID: PMC7470844 DOI: 10.7554/elife.55778] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 08/07/2020] [Indexed: 12/30/2022] Open
Abstract
During development, cells gradually assume specialized fates via changes of transcriptional dynamics, sometimes even within the same developmental stage. For anterior-posterior (AP) patterning in metazoans, it has been suggested that the gradual transition from a dynamic genetic regime to a static one is encoded by different transcriptional modules. In that case, the static regime has an essential role in pattern formation in addition to its maintenance function. In this work, we introduce a geometric approach to study such transition. We exhibit two types of genetic regime transitions arising through local or global bifurcations, respectively. We find that the global bifurcation type is more generic, more robust, and better preserves dynamical information. This could parsimoniously explain common features of metazoan segmentation, such as changes of periods leading to waves of gene expressions, ‘speed/frequency-gradient’ dynamics, and changes of wave patterns. Geometric approaches appear as possible alternatives to gene regulatory networks to understand development.
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Affiliation(s)
| | - Ezzat El-Sherif
- Division of Developmental Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Paul François
- Department of Physics, McGill University, Montreal, Canada
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21
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Meeuse MWM, Hauser YP, Morales Moya LJ, Hendriks G, Eglinger J, Bogaarts G, Tsiairis C, Großhans H. Developmental function and state transitions of a gene expression oscillator in Caenorhabditis elegans. Mol Syst Biol 2020; 16:e9498. [PMID: 32687264 PMCID: PMC7370751 DOI: 10.15252/msb.20209498] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/15/2020] [Accepted: 06/22/2020] [Indexed: 11/26/2022] Open
Abstract
Gene expression oscillators can structure biological events temporally and spatially. Different biological functions benefit from distinct oscillator properties. Thus, finite developmental processes rely on oscillators that start and stop at specific times, a poorly understood behavior. Here, we have characterized a massive gene expression oscillator comprising > 3,700 genes in Caenorhabditis elegans larvae. We report that oscillations initiate in embryos, arrest transiently after hatching and in response to perturbation, and cease in adults. Experimental observation of the transitions between oscillatory and non-oscillatory states at high temporal resolution reveals an oscillator operating near a Saddle Node on Invariant Cycle (SNIC) bifurcation. These findings constrain the architecture and mathematical models that can represent this oscillator. They also reveal that oscillator arrests occur reproducibly in a specific phase. Since we find oscillations to be coupled to developmental processes, including molting, this characteristic of SNIC bifurcations endows the oscillator with the potential to halt larval development at defined intervals, and thereby execute a developmental checkpoint function.
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Affiliation(s)
- Milou WM Meeuse
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
- University of BaselBaselSwitzerland
| | - Yannick P Hauser
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
- University of BaselBaselSwitzerland
| | | | - Gert‐Jan Hendriks
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
- University of BaselBaselSwitzerland
| | - Jan Eglinger
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
| | | | - Charisios Tsiairis
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
| | - Helge Großhans
- Friedrich Miescher Institute for Biomedical Research (FMI)BaselSwitzerland
- University of BaselBaselSwitzerland
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22
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Venzin OF, Oates AC. What are you synching about? Emerging complexity of Notch signaling in the segmentation clock. Dev Biol 2020; 460:40-54. [DOI: 10.1016/j.ydbio.2019.06.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/30/2019] [Accepted: 06/30/2019] [Indexed: 10/26/2022]
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23
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Tietz KT, Gallagher TL, Mannings MC, Morrow ZT, Derr NL, Amacher SL. Pumilio response and AU-rich elements drive rapid decay of Pnrc2-regulated cyclic gene transcripts. Dev Biol 2020; 462:129-140. [PMID: 32246943 DOI: 10.1016/j.ydbio.2020.03.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 02/18/2020] [Accepted: 03/20/2020] [Indexed: 01/06/2023]
Abstract
Vertebrate segmentation is regulated by the segmentation clock, a biological oscillator that controls periodic formation of somites, or embryonic segments, which give rise to many mesodermal tissue types. This molecular oscillator generates cyclic gene expression with the same periodicity as somite formation in the presomitic mesoderm (PSM), an area of mesenchymal cells that give rise to mature somites. Molecular components of the clock include the Hes/her family of genes that encode transcriptional repressors, but additional genes cycle. Cyclic gene transcripts are cleared rapidly, and clearance depends upon the pnrc2 (proline-rich nuclear receptor co-activator 2) gene that encodes an mRNA decay adaptor. Previously, we showed that the her1 3'UTR confers instability to otherwise stable transcripts in a Pnrc2-dependent manner, however, the molecular mechanism(s) by which cyclic gene transcripts are cleared remained largely unknown. To identify features of the her1 3'UTR that are critical for Pnrc2-mediated decay, we developed an array of transgenic inducible reporter lines carrying different regions of the 3'UTR. We find that the terminal 179 nucleotides (nts) of the her1 3'UTR are necessary and sufficient to confer rapid instability. Additionally, we show that the 3'UTR of another cyclic gene, deltaC (dlc), also confers Pnrc2-dependent instability. Motif analysis reveals that both her1 and dlc 3'UTRs contain terminally-located Pumilio response elements (PREs) and AU-rich elements (AREs), and we show that the PRE and ARE in the last 179 nts of the her1 3'UTR drive rapid turnover of reporter mRNA. Finally, we show that mutation of Pnrc2 residues and domains that are known to facilitate interaction of human PNRC2 with decay factors DCP1A and UPF1 reduce the ability of Pnrc2 to restore normal cyclic gene expression in pnrc2 mutant embryos. Our findings suggest that Pnrc2 interacts with decay machinery components and cooperates with Pumilio (Pum) proteins and ARE-binding proteins to promote rapid turnover of cyclic gene transcripts during somitogenesis.
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Affiliation(s)
- Kiel T Tietz
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA; Interdisciplinary Graduate Program in Molecular, Cellular and Developmental Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Thomas L Gallagher
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Monica C Mannings
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA; Interdisciplinary Graduate Program in Molecular, Cellular and Developmental Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Zachary T Morrow
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
| | - Nicolas L Derr
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
| | - Sharon L Amacher
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA; Interdisciplinary Graduate Program in Molecular, Cellular and Developmental Biology, The Ohio State University, Columbus, OH, 43210, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA; Center for Muscle Health and Neuromuscular Disorders, The Ohio State University, Columbus, OH, 43210, USA.
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24
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Bhavna R. Segmentation clock dynamics is strongly synchronized in the forming somite. Dev Biol 2020; 460:55-69. [PMID: 30926261 DOI: 10.1016/j.ydbio.2019.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 10/27/2022]
Abstract
During vertebrate somitogenesis an inherent segmentation clock coordinates the spatiotemporal signaling to generate segmented structures that pattern the body axis. Using our experimental and quantitative approach, we study the cell movements and the genetic oscillations of her1 expression level at single-cell resolution simultaneously and scale up to the entire pre-somitic mesoderm (PSM) tissue. From the experimentally determined phases of PSM cellular oscillators, we deduced an in vivo frequency profile gradient along the anterior-posterior PSM axis and inferred precise mathematical relations between spatial cell-level period and tissue-level somitogenesis period. We also confirmed a gradient in the relative velocities of cellular oscillators along the axis. The phase order parameter within an ensemble of oscillators revealed the degree of synchronization in the tailbud and the posterior PSM being only partial, whereas synchronization can be almost complete in the presumptive somite region but with temporal oscillations. Collectively, the degree of synchronization itself, possibly regulated by cell movement and the synchronized temporal phase of the transiently expressed clock protein Her1, can be an additional control mechanism for making precise somite boundaries.
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Affiliation(s)
- Rajasekaran Bhavna
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany; Max Planck Institute for the Physics of Complex Systems, 01187, Dresden, Germany; Tata Institute of Fundamental Research, 400005, Mumbai, India.
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25
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Naoki H, Matsui T. Somite boundary determination in normal and clock-less vertebrate embryos. Dev Growth Differ 2020; 62:177-187. [PMID: 32108939 DOI: 10.1111/dgd.12655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 12/21/2022]
Abstract
Vertebrate segments called somites are generated by periodic segmentation of the presomitic mesoderm (PSM). In the most accepted theoretical model for somite segmentation, the clock and wavefront (CW) model, a clock that ticks to determine particular timings and a wavefront that moves posteriorly are presented in the PSM, and somite positions are determined when the clock meets the posteriorly moving wavefront somewhere in the PSM. Over the last two decades, it has been revealed that the molecular mechanism of the clock and wavefront in vertebrates is based on clock genes including Hes family transcription factors and Notch effectors that oscillate within the PSM to determine particular timings and fibroblast growth factor (FGF) gradients, acting as the posteriorly moving wavefront to determine the position of somite segmentation. A clock-less condition in the CW model was predicted to form no somites; however, irregularly sized somites were still formed in mice and zebrafish, suggesting that this was one of the limitations of the CW model. Recently, we performed interdisciplinary research of experimental and theoretical biological studies and revealed the mechanisms of somite boundary determination in normal and clock-less conditions by characterization of the FGF/extracellular signal-regulated kinase (ERK) activity dynamics. Since features of the molecular clock have already been described in-depth in several reviews, we summarized recent findings regarding the role of FGF/ERK signaling in somite boundary formation and described our current understanding of how FGF/ERK signaling contributes to somitogenesis in normal and clock-less conditions in this review.
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Affiliation(s)
- Honda Naoki
- Laboratory of Theoretical Biology, Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, Japan
| | - Takaaki Matsui
- Gene Regulation Research, Division of Biological Science, Nara Institute of Science and Technology, Takayama, Nara, Japan
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26
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Boareto M. Patterning via local cell-cell interactions in developing systems. Dev Biol 2019; 460:77-85. [PMID: 31866513 DOI: 10.1016/j.ydbio.2019.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 01/26/2023]
Abstract
Spatial patterning during embryonic development emerges from the differentiation of progenitor cells that share the same genetic program. One of the main challenges in systems biology is to understand the relationship between gene network and patterning, especially how the cells communicate to coordinate their differentiation. This review aims to describe the principles of pattern formation from local cell-cell interactions mediated by the Notch signalling pathway. Notch mediates signalling via direct cell-cell contact and regulates cell fate decisions in many tissues during embryonic development. Here, I will describe the patterning mechanisms via different Notch ligands and the critical role of Notch oscillations during the segmentation of the vertebrate body, brain development, and blood vessel formation.
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Affiliation(s)
- Marcelo Boareto
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058, Basel, Switzerland; Swiss Institute of Bioinformatics, Mattenstrasse 26, 4058, Basel, Switzerland.
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27
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Peyret G, Mueller R, d'Alessandro J, Begnaud S, Marcq P, Mège RM, Yeomans JM, Doostmohammadi A, Ladoux B. Sustained Oscillations of Epithelial Cell Sheets. Biophys J 2019; 117:464-478. [PMID: 31307676 DOI: 10.1016/j.bpj.2019.06.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022] Open
Abstract
Morphological changes during development, tissue repair, and disease largely rely on coordinated cell movements and are controlled by the tissue environment. Epithelial cell sheets are often subjected to large-scale deformation during tissue formation. The active mechanical environment in which epithelial cells operate have the ability to promote collective oscillations, but how these cellular movements are generated and relate to collective migration remains unclear. Here, combining in vitro experiments and computational modeling, we describe a form of collective oscillations in confined epithelial tissues in which the oscillatory motion is the dominant contribution to the cellular movements. We show that epithelial cells exhibit large-scale coherent oscillations when constrained within micropatterns of varying shapes and sizes and that their period and amplitude are set by the smallest confinement dimension. Using molecular perturbations, we then demonstrate that force transmission at cell-cell junctions and its coupling to cell polarity are pivotal for the generation of these collective movements. We find that the resulting tissue deformations are sufficient to trigger osillatory mechanotransduction of YAP within cells, potentially affecting a wide range of cellular processes.
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Affiliation(s)
- Grégoire Peyret
- Institut Jacques Monod, CNRS UMR 7592 et Université Paris Diderot, Paris, France
| | - Romain Mueller
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, United Kingdom
| | - Joseph d'Alessandro
- Institut Jacques Monod, CNRS UMR 7592 et Université Paris Diderot, Paris, France
| | - Simon Begnaud
- Institut Jacques Monod, CNRS UMR 7592 et Université Paris Diderot, Paris, France
| | - Philippe Marcq
- Laboratoire Physique et Mécanique des Milieux Hétérogènes, CNRS UMR 7636, Sorbonne Université, ESPCI, Paris, France
| | - René-Marc Mège
- Institut Jacques Monod, CNRS UMR 7592 et Université Paris Diderot, Paris, France
| | - Julia M Yeomans
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, United Kingdom
| | - Amin Doostmohammadi
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, United Kingdom.
| | - Benoît Ladoux
- Institut Jacques Monod, CNRS UMR 7592 et Université Paris Diderot, Paris, France.
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28
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Vroomans RMA, Hogeweg P, ten Tusscher KHWJ. Around the clock: gradient shape and noise impact the evolution of oscillatory segmentation dynamics. EvoDevo 2018; 9:24. [PMID: 30555670 PMCID: PMC6288972 DOI: 10.1186/s13227-018-0113-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Segmentation, the subdivision of the major body axis into repeated elements, is considered one of the major evolutionary innovations in bilaterian animals. In all three segmented animal clades, the predominant segmentation mechanism is sequential segmentation, where segments are generated one by one in anterior-posterior order from a posterior undifferentiated zone. In vertebrates and arthropods, sequential segmentation is thought to arise from a clock-and-wavefront-type mechanism, where oscillations in the posterior growth zone are transformed into a segmental prepattern in the anterior by a receding wavefront. Previous evo-devo simulation studies have demonstrated that this segmentation type repeatedly arises, supporting the idea of parallel evolutionary origins in these animal clades. Sequential segmentation has been studied most extensively in vertebrates, where travelling waves have been observed that reflect the slowing down of oscillations prior to their cessation and where these oscillations involve a highly complex regulatory network. It is currently unclear under which conditions this oscillator complexity and slowing should be expected to evolve, how they are related and to what extent similar properties should be expected for sequential segmentation in other animal species. RESULTS To investigate these questions, we extend a previously developed computational model for the evolution of segmentation. We vary the slope of the posterior morphogen gradient and the strength of gene expression noise. We find that compared to a shallow gradient, a steep morphogen gradient allows for faster evolution and evolved oscillator networks are simpler. Furthermore, under steep gradients, damped oscillators often evolve, whereas shallow gradients appear to require persistent oscillators which are regularly accompanied by travelling waves, indicative of a frequency gradient. We show that gene expression noise increases the likelihood of evolving persistent oscillators under steep gradients and of evolving frequency gradients under shallow gradients. Surprisingly, we find that the evolutions of oscillator complexity and travelling waves are not correlated, suggesting that these properties may have evolved separately. CONCLUSIONS Based on our findings, we suggest that travelling waves may have evolved in response to shallow morphogen gradients and gene expression noise. These two factors may thus also be responsible for the observed differences between different species within both the arthropod and chordate phyla.
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Affiliation(s)
- Renske M. A. Vroomans
- Centre of Excellence in Experimental and Computational Developmental Biology, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00790 Helsinki, Finland
- Theoretical Biology, Utrecht University, Padualaan 8, 3584CH Utrecht, Netherlands
| | - Paulien Hogeweg
- Theoretical Biology, Utrecht University, Padualaan 8, 3584CH Utrecht, Netherlands
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29
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30
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Ishimatsu K, Hiscock TW, Collins ZM, Sari DWK, Lischer K, Richmond DL, Bessho Y, Matsui T, Megason SG. Size-reduced embryos reveal a gradient scaling-based mechanism for zebrafish somite formation. Development 2018; 145:dev.161257. [PMID: 29769221 DOI: 10.1242/dev.161257] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 05/09/2018] [Indexed: 12/29/2022]
Abstract
Little is known about how the sizes of animal tissues are controlled. A prominent example is somite size, which varies widely both within an individual and across species. Despite intense study of the segmentation clock governing the timing of somite generation, how it relates to somite size is poorly understood. Here, we examine somite scaling and find that somite size at specification scales with the length of the presomitic mesoderm (PSM) despite considerable variation in PSM length across developmental stages and in surgically size-reduced embryos. Measurement of clock period, axis elongation speed and clock gene expression patterns demonstrate that existing models fail to explain scaling. We posit a 'clock and scaled gradient' model, in which somite boundaries are set by a dynamically scaling signaling gradient across the PSM. Our model not only explains existing data, but also makes a unique prediction that we confirm experimentally - the formation of periodic 'echoes' in somite size following perturbation of the size of one somite. Our findings demonstrate that gradient scaling plays a central role in both progression and size control of somitogenesis.
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Affiliation(s)
- Kana Ishimatsu
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Tom W Hiscock
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Zach M Collins
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Dini Wahyu Kartika Sari
- Gene Regulation Research, Nara Institute of Science and Technology, Nara 630-0101, Japan.,Department of Fisheries, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Kenny Lischer
- Gene Regulation Research, Nara Institute of Science and Technology, Nara 630-0101, Japan
| | - David L Richmond
- Image and Data Analysis Core, Harvard Medical School, Boston, MA 02115, USA
| | - Yasumasa Bessho
- Gene Regulation Research, Nara Institute of Science and Technology, Nara 630-0101, Japan
| | - Takaaki Matsui
- Gene Regulation Research, Nara Institute of Science and Technology, Nara 630-0101, Japan
| | - Sean G Megason
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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31
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Tomka T, Iber D, Boareto M. Travelling waves in somitogenesis: Collective cellular properties emerge from time-delayed juxtacrine oscillation coupling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 137:76-87. [PMID: 29702125 DOI: 10.1016/j.pbiomolbio.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 04/09/2018] [Accepted: 04/12/2018] [Indexed: 11/18/2022]
Abstract
The sculpturing of the vertebrate body plan into segments begins with the sequential formation of somites in the presomitic mesoderm (PSM). The rhythmicity of this process is controlled by travelling waves of gene expression. These kinetic waves emerge from coupled cellular oscillators and sweep across the PSM. In zebrafish, the oscillations are driven by autorepression of her genes and are synchronized via Notch signalling. Mathematical modelling has played an important role in explaining how collective properties emerge from the molecular interactions. Increasingly more quantitative experimental data permits the validation of those mathematical models, yet leads to increasingly more complex model formulations that hamper an intuitive understanding of the underlying mechanisms. Here, we review previous efforts, and design a mechanistic model of the her1 oscillator, which represents the experimentally viable her7;hes6 double mutant. This genetically simplified system is ideally suited to conceptually recapitulate oscillatory entrainment and travelling wave formation, and to highlight open questions. It shows that three key parameters, the autorepression delay, the juxtacrine coupling delay, and the coupling strength, are sufficient to understand the emergence of the collective period, the collective amplitude, and the synchronization of neighbouring Her1 oscillators. Moreover, two spatiotemporal time delay gradients, in the autorepression and in the juxtacrine signalling, are required to explain the collective oscillatory dynamics and synchrony of PSM cells. The highlighted developmental principles likely apply more generally to other developmental processes, including neurogenesis and angiogenesis.
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Affiliation(s)
- Tomas Tomka
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Dagmar Iber
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, Mattenstrasse 26, 4058 Basel, Switzerland.
| | - Marcelo Boareto
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, Mattenstrasse 26, 4058 Basel, Switzerland.
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Abstract
Segmentation is the partitioning of the body axis into a series of repeating units or segments. This widespread body plan is found in annelids, arthropods, and chordates, showing it to be a successful developmental strategy for growing and generating diverse morphology and anatomy. Segmentation has been extensively studied over the years. Forty years ago, Cooke and Zeeman published the Clock and Wavefront model, creating a theoretical framework of how developing cells could acquire and keep temporal and spatial information in order to generate a segmented pattern. Twenty years later, in 1997, Palmeirim and co-workers found the first clock gene whose oscillatory expression pattern fitted within Cooke and Zeeman's model. Currently, in 2017, new experimental techniques, such as new ex vivo experimental models, real-time imaging of gene expression, live single cell tracking, and simplified transgenics approaches, are revealing some of the fine details of the molecular processes underlying the inner workings of the segmentation mechanisms, bringing new insights into this fundamental process. Here we review and discuss new emerging views that further our understanding of the vertebrate segmentation clock, with a particular emphasis on recent publications that challenge and/or complement the currently accepted Clock and Wavefront model.
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Affiliation(s)
- Tomás Pais-de-Azevedo
- Algarve Biomedical Center, Faro, Portugal
- CBMR, Centre for Biomedical Research, University of Algarve, Faro, Portugal
| | - Ramiro Magno
- Algarve Biomedical Center, Faro, Portugal
- CBMR, Centre for Biomedical Research, University of Algarve, Faro, Portugal
- Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, Netherlands
| | - Isabel Duarte
- Algarve Biomedical Center, Faro, Portugal
- CBMR, Centre for Biomedical Research, University of Algarve, Faro, Portugal
| | - Isabel Palmeirim
- Algarve Biomedical Center, Faro, Portugal
- CBMR, Centre for Biomedical Research, University of Algarve, Faro, Portugal
- Department of Biomedical Sciences and Medicine, University of Algarve, Faro, Portugal
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33
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Naganathan SR, Oates AC. Mechanochemical coupling and developmental pattern formation. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.coisb.2017.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Wahi K, Friesen S, Coppola V, Cole SE. Putative binding sites for mir-125 family miRNAs in the mouse Lfng 3'UTR affect transcript expression in the segmentation clock, but mir-125a-5p is dispensable for normal somitogenesis. Dev Dyn 2017; 246:740-748. [PMID: 28710810 PMCID: PMC5597482 DOI: 10.1002/dvdy.24552] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/21/2017] [Accepted: 07/01/2017] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND In vertebrate embryos, a "segmentation clock" times somitogenesis. Clock-linked genes, including Lunatic fringe (Lfng), exhibit cyclic expression in the presomitic mesoderm (PSM), with a period matching the rate of somite formation. The clock period varies widely across species, but the mechanisms that underlie this variability are not clear. The half-lives of clock components are proposed to influence the rate of clock oscillations, and are tightly regulated in the PSM. Interactions between Lfng and mir-125a-5p in the embryonic chicken PSM promote Lfng transcript instability, but the conservation of this mechanism in other vertebrates has not been tested. Here, we examine whether this interaction affects clock activity in a mammalian species. RESULTS Mutation of mir-125 binding sites in the Lfng 3'UTR leads to persistent, nonoscillatory reporter transcript expression in the caudal-most mouse PSM, although dynamic transcript expression recovers in the central PSM. Despite this, expression of endogenous mir-125a-5p is dispensable for mouse somitogenesis. CONCLUSIONS These results suggest that mir-125a sites in the Lfng 3' untranslated region influence transcript turnover in both mouse and chicken embryos, and support the existence of position-dependent regulatory mechanisms in the PSM. They further suggest the existence of compensatory mechanisms that can rescue the loss of mir-125a-5p in mice. Developmental Dynamics 246:740-748, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kanu Wahi
- Department of Molecular Genetics, College of Arts and Sciences, The Ohio State University, Columbus, Ohio
| | - Sophia Friesen
- Department of Molecular Genetics, College of Arts and Sciences, The Ohio State University, Columbus, Ohio
| | - Vincenzo Coppola
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Susan E Cole
- Department of Molecular Genetics, College of Arts and Sciences, The Ohio State University, Columbus, Ohio
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Pnrc2 regulates 3'UTR-mediated decay of segmentation clock-associated transcripts during zebrafish segmentation. Dev Biol 2017. [PMID: 28648842 DOI: 10.1016/j.ydbio.2017.06.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Vertebrate segmentation is controlled by the segmentation clock, a molecular oscillator that regulates gene expression and cycles rapidly. The expression of many genes oscillates during segmentation, including hairy/Enhancer of split-related (her or Hes) genes, which encode transcriptional repressors that auto-inhibit their own expression, and deltaC (dlc), which encodes a Notch ligand. We previously identified the tortuga (tor) locus in a zebrafish forward genetic screen for genes involved in cyclic transcript regulation and showed that cyclic transcripts accumulate post-splicing in tor mutants. Here we show that cyclic mRNA accumulation in tor mutants is due to loss of pnrc2, which encodes a proline-rich nuclear receptor co-activator implicated in mRNA decay. Using an inducible in vivo reporter system to analyze transcript stability, we find that the her1 3'UTR confers Pnrc2-dependent instability to a heterologous transcript. her1 mRNA decay is Dicer-independent and likely employs a Pnrc2-Upf1-containing mRNA decay complex. Surprisingly, despite accumulation of cyclic transcripts in pnrc2-deficient embryos, we find that cyclic protein is expressed normally. Overall, we show that Pnrc2 promotes 3'UTR-mediated decay of developmentally-regulated segmentation clock transcripts and we uncover an additional post-transcriptional regulatory layer that ensures oscillatory protein expression in the absence of cyclic mRNA decay.
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36
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Uriu K, Morelli LG. Determining the impact of cell mixing on signaling during development. Dev Growth Differ 2017. [PMID: 28627749 DOI: 10.1111/dgd.12366] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cell movement and intercellular signaling occur simultaneously to organize morphogenesis during embryonic development. Cell movement can cause relative positional changes between neighboring cells. When intercellular signals are local such cell mixing may affect signaling, changing the flow of information in developing tissues. Little is known about the effect of cell mixing on intercellular signaling in collective cellular behaviors and methods to quantify its impact are lacking. Here we discuss how to determine the impact of cell mixing on cell signaling drawing an example from vertebrate embryogenesis: the segmentation clock, a collective rhythm of interacting genetic oscillators. We argue that comparing cell mixing and signaling timescales is key to determining the influence of mixing. A signaling timescale can be estimated by combining theoretical models with cell signaling perturbation experiments. A mixing timescale can be obtained by analysis of cell trajectories from live imaging. After comparing cell movement analyses in different experimental settings, we highlight challenges in quantifying cell mixing from embryonic timelapse experiments, especially a reference frame problem due to embryonic motions and shape changes. We propose statistical observables characterizing cell mixing that do not depend on the choice of reference frames. Finally, we consider situations in which both cell mixing and signaling involve multiple timescales, precluding a direct comparison between single characteristic timescales. In such situations, physical models based on observables of cell mixing and signaling can simulate the flow of information in tissues and reveal the impact of observed cell mixing on signaling.
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Affiliation(s)
- Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Luis G Morelli
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Godoy Cruz 2390, C1425FQD, Buenos Aires, Argentina.,Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Otto-Hahn-Str. 11, 44227, Dortmund, Germany.,Departamento de Física, FCEyN, UBA, Pabellon 1, Ciudad Universitaria, 1428, Buenos Aires, Argentina
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37
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Vroomans RMA, Ten Tusscher KHWJ. Modelling asymmetric somitogenesis: Deciphering the mechanisms behind species differences. Dev Biol 2017; 427:21-34. [PMID: 28506615 DOI: 10.1016/j.ydbio.2017.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 05/10/2017] [Accepted: 05/10/2017] [Indexed: 02/05/2023]
Abstract
Somitogenesis is one of the major hallmarks of bilateral symmetry in vertebrates. This symmetry is lost when retinoic acid (RA) signalling is inhibited, allowing the left-right determination pathway to influence somitogenesis. In all three studied vertebrate model species, zebrafish, chicken and mouse, the frequency of somite formation becomes asymmetric, with slower gene expression oscillations driving somitogenesis on the right side. Still, intriguingly, the resulting left-right asymmetric phenotypes differ significantly between these model species. While somitogenesis is generally considered as functionally equivalent among different vertebrates, substantial differences exist in the subset of oscillating genes between different vertebrate species. Variation also appears to exist in the way oscillations cease and somite boundaries become patterned. In addition, in absence of RA, the FGF8 gradient thought to constitute the determination wavefront becomes asymmetric in zebrafish and mouse, extending more anteriorly to the right, while remaining symmetric in chicken. Here we use a computational modelling approach to decipher the causes underlying species differences in asymmetric somitogenesis. Specifically, we investigate to what extent differences can be explained from observed differences in FGF asymmetry and whether differences in somite determination dynamics may also be involved. We demonstrate that a simple clock-and-wavefront model incorporating the observed left-right differences in somitogenesis frequency readily reproduces asymmetric somitogenesis in chicken. However, incorporating asymmetry in FGF signalling was insufficient to robustly reproduce mouse or zebrafish asymmetry phenotypes. In order to explain these phenoptypes we needed to extend the basic model, incorporating species-specific details of the somitogenesis determination mechanism. Our results thus demonstrate that a combination of differences in FGF dynamics and somite determination cause species differences in asymmetric somitogenesis. In addition,they highlight the power of using computational models as well as studying left-right asymmetry to obtain more insight in somitogenesis.
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38
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Liao BK, Oates AC. Delta-Notch signalling in segmentation. ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:429-447. [PMID: 27888167 PMCID: PMC5446262 DOI: 10.1016/j.asd.2016.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 11/20/2016] [Accepted: 11/21/2016] [Indexed: 06/06/2023]
Abstract
Modular body organization is found widely across multicellular organisms, and some of them form repetitive modular structures via the process of segmentation. It's vastly interesting to understand how these regularly repeated structures are robustly generated from the underlying noise in biomolecular interactions. Recent studies from arthropods reveal similarities in segmentation mechanisms with vertebrates, and raise the possibility that the three phylogenetic clades, annelids, arthropods and chordates, might share homology in this process from a bilaterian ancestor. Here, we discuss vertebrate segmentation with particular emphasis on the role of the Notch intercellular signalling pathway. We introduce vertebrate segmentation and Notch signalling, pointing out historical milestones, then describe existing models for the Notch pathway in the synchronization of noisy neighbouring oscillators, and a new role in the modulation of gene expression wave patterns. We ask what functions Notch signalling may have in arthropod segmentation and explore the relationship between Notch-mediated lateral inhibition and synchronization. Finally, we propose open questions and technical challenges to guide future investigations into Notch signalling in segmentation.
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Affiliation(s)
- Bo-Kai Liao
- Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
| | - Andrew C Oates
- Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK; Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
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39
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Abstract
Skeletal muscle performs an essential function in human physiology with defects in genes encoding a variety of cellular components resulting in various types of inherited muscle disorders. Muscular dystrophies (MDs) are a severe and heterogeneous type of human muscle disease, manifested by progressive muscle wasting and degeneration. The disease pathogenesis and therapeutic options for MDs have been investigated for decades using rodent models, and considerable knowledge has been accumulated on the cause and pathogenetic mechanisms of this group of human disorders. However, due to some differences between disease severity and progression, what is learned in mammalian models does not always transfer to humans, prompting the desire for additional and alternative models. More recently, zebrafish have emerged as a novel and robust animal model for the study of human muscle disease. Zebrafish MD models possess a number of distinct advantages for modeling human muscle disorders, including the availability and ease of generating mutations in homologous disease-causing genes, the ability to image living muscle tissue in an intact animal, and the suitability of zebrafish larvae for large-scale chemical screens. In this chapter, we review the current understanding of molecular and cellular mechanisms involved in MDs, the process of myogenesis in zebrafish, and the structural and functional characteristics of zebrafish larval muscles. We further discuss the insights gained from the key zebrafish MD models that have been so far generated, and we summarize the attempts that have been made to screen for small molecules inhibitors of the dystrophic phenotypes using these models. Overall, these studies demonstrate that zebrafish is a useful in vivo system for modeling aspects of human skeletal muscle disorders. Studies using these models have contributed both to the understanding of the pathogenesis of muscle wasting disorders and demonstrated their utility as highly relevant models to implement therapeutic screening regimens.
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Affiliation(s)
- M Li
- Monash University, Clayton, VIC, Australia
| | - K J Hromowyk
- The Ohio State University, Columbus, OH, United States
| | - S L Amacher
- The Ohio State University, Columbus, OH, United States
| | - P D Currie
- Monash University, Clayton, VIC, Australia
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40
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Beaupeux M, François P. Positional information from oscillatory phase shifts : insights from in silico evolution. Phys Biol 2016; 13:036009. [PMID: 27346171 DOI: 10.1088/1478-3975/13/3/036009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Complex cellular decisions are based on temporal dynamics of pathways, including genetic oscillators. In development, recent works on vertebrae formation have suggested that relative phase of genetic oscillators encode positional information, including differentiation front defining vertebrae positions. Precise mechanisms for this are still unknown. Here, we use computational evolution to find gene network topologies that can compute the phase difference between oscillators and convert it into a decoder morphogen concentration. Two types of networks are discovered, based on symmetry properties of the decoder gene. So called asymmetric networks are studied, and two submodules are identified converting phase information into an amplitude variable. Those networks naturally display a 'shock' for a well defined phase difference, that can be used to define a wavefront of differentiation. We show how implementation of these ideas reproduce experimental features of vertebrate segmentation.
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Affiliation(s)
- M Beaupeux
- Ernest Rutherford Physics Building, McGill University, H3A2T8 Montreal QC, Canada
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41
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Webb AB, Lengyel IM, Jörg DJ, Valentin G, Jülicher F, Morelli LG, Oates AC. Persistence, period and precision of autonomous cellular oscillators from the zebrafish segmentation clock. eLife 2016; 5. [PMID: 26880542 PMCID: PMC4803185 DOI: 10.7554/elife.08438] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 02/11/2016] [Indexed: 12/11/2022] Open
Abstract
In vertebrate development, the sequential and rhythmic segmentation of the body axis
is regulated by a “segmentation clock”. This clock is comprised of a population of
coordinated oscillating cells that together produce rhythmic gene expression patterns
in the embryo. Whether individual cells autonomously maintain oscillations, or
whether oscillations depend on signals from neighboring cells is unknown. Using a
transgenic zebrafish reporter line for the cyclic transcription factor Her1, we
recorded single tailbud cells in vitro. We demonstrate that individual cells can
behave as autonomous cellular oscillators. We described the observed variability in
cell behavior using a theory of generic oscillators with correlated noise. Single
cells have longer periods and lower precision than the tissue, highlighting the role
of collective processes in the segmentation clock. Our work reveals a population of
cells from the zebrafish segmentation clock that behave as self-sustained, autonomous
oscillators with distinctive noisy dynamics. DOI:http://dx.doi.org/10.7554/eLife.08438.001 The timing and pattern of gene activity in cells can be very important. For example,
precise gene activity patterns in 24-hour circadian clocks help to set daily cycles
of rest and activity in organisms. In such scenarios, cells often communicate with
each other to coordinate the activity of their genes. To fully understand how the
behavior of the population emerges, scientists must first understand the gene
activity patterns in individual cells. Rhythmic gene activity is essential for the spinal column to form in fish and other
vertebrate embryos. A group of cells that switch genes on/off in a coordinated
pattern act like a clock to regulate the timing of the various steps in the process
of backbone formation. However, it is not clear if each cell is able to maintain a
rhythm of gene expression on their own, or whether they rely on messages from
neighboring cells to achieve it. Now, Webb et al. use time-lapse videos of individual cells isolated from the tail of
zebrafish embryos to show that each cell can maintain a pattern of rhythmic activity
in a gene called Her1. In the experiments, individual cells were
removed from zebrafish and placed under a microscope to record and track the activity
of Her1 over time using fluorescent proteins. These experiments show
that each cell is able to maintain a rhythmic pattern of Her1
expression on its own. Webb et al. then compared the Her1 activity patterns in individual
cells with the Her1 patterns present in a larger piece of zebrafish
tissue. The experiments showed that the rhythms in the individual cells are slower
and less precise in their timing than in the tissue. This suggests that groups of
cells must work together to create the synchronized rhythms of gene expression with
the right precision and timing needed for the spinal column to be patterned
correctly. In the future, further experiment with these cells will allow researchers to
investigate the genetic basis of the rhythms in single cells, and find out how
individual cells work together with their neighbors to allow tissues to work
properly. DOI:http://dx.doi.org/10.7554/eLife.08438.002
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Affiliation(s)
- Alexis B Webb
- MRC-National Institute for Medical Research, London, United Kingdom.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Iván M Lengyel
- Departamento de Física, FCEyN UBA and IFIBA, CONICET, Buenos Aires, Argentina
| | - David J Jörg
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Guillaume Valentin
- MRC-National Institute for Medical Research, London, United Kingdom.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Luis G Morelli
- Departamento de Física, FCEyN UBA and IFIBA, CONICET, Buenos Aires, Argentina
| | - Andrew C Oates
- MRC-National Institute for Medical Research, London, United Kingdom.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Department of Cell and Developmental Biology, University College London, London, United Kingdom
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42
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Webb AB, Oates AC. Timing by rhythms: Daily clocks and developmental rulers. Dev Growth Differ 2016; 58:43-58. [PMID: 26542934 PMCID: PMC4832293 DOI: 10.1111/dgd.12242] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/18/2015] [Accepted: 09/19/2015] [Indexed: 01/10/2023]
Abstract
Biological rhythms are widespread, allowing organisms to temporally organize their behavior and metabolism in advantageous ways. Such proper timing of molecular and cellular events is critical to their development and health. This is best understood in the case of the circadian clock that orchestrates the daily sleep/wake cycle of organisms. Temporal rhythms can also be used for spatial organization, if information from an oscillating system can be recorded within the tissue in a manner that leaves a permanent periodic pattern. One example of this is the "segmentation clock" used by the vertebrate embryo to rhythmically and sequentially subdivide its elongating body axis. The segmentation clock moves with the elongation of the embryo, such that its period sets the segment length as the tissue grows outward. Although the study of this system is still relatively young compared to the circadian clock, outlines of molecular, cellular, and tissue-level regulatory mechanisms of timing have emerged. The question remains, however, is it truly a clock? Here we seek to introduce the segmentation clock to a wider audience of chronobiologists, focusing on the role and control of timing in the system. We compare and contrast the segmentation clock with the circadian clock, and propose that the segmentation clock is actually an oscillatory ruler, with a primary function to measure embryonic space.
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Affiliation(s)
- Alexis B Webb
- The Francis Crick Institute, Mill Hill Laboratory, London, UK
| | - Andrew C Oates
- The Francis Crick Institute, Mill Hill Laboratory, London, UK
- University College London, Gower Street, London, UK
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43
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Yabe T, Takada S. Molecular mechanism for cyclic generation of somites: Lessons from mice and zebrafish. Dev Growth Differ 2015; 58:31-42. [PMID: 26676827 DOI: 10.1111/dgd.12249] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 12/23/2022]
Abstract
The somite is the most prominent metameric structure observed during vertebrate embryogenesis, and its metamerism preserves the characteristic structures of the vertebrae and muscles in the adult body. During vertebrate somitogenesis, sequential formation of epithelialized cell boundaries generates the somites. According to the "clock and wavefront model," the periodical and sequential generation of somites is achieved by the integration of spatiotemporal information provided by the segmentation clock and wavefront. In the anterior region of the presomitic mesoderm, which is the somite precursor, the orchestration between the segmentation clock and the wavefront achieves morphogenesis of somites through multiple processes such as determination of somite boundary position, generation of morophological boundary, and establishment of the rostrocaudal polarity within a somite. Recently, numerous studies using various model animals including mouse, zebrafish, and chick have gradually revealed the molecular aspect of the "clock and wavefront" model and the molecular mechanism connecting the segmentation clock and the wavefront to the multiple processes of somite morphogenesis. In this review, we first summarize the current knowledge about the molecular mechanisms underlying the clock and the wavefront and then describe those of the three processes of somite morphogenesis. Especially, we will discuss the conservation and diversification in the molecular network of the somitigenesis among vertebrates, focusing on two typical model animals used for genetic analyses, i.e., the mouse and zebrafish. In this review, we described molecular mechanism for the generation of somites based on the spatiotemporal information provided by "segmentation clock" and "wavefront" focusing on the evidences obtained from mouse and zebrafish.
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Affiliation(s)
- Taijiro Yabe
- Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan.,The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, 444-8787, Japan
| | - Shinji Takada
- Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan.,The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, 444-8787, Japan
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44
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Meinhardt H. Models for patterning primary embryonic body axes: The role of space and time. Semin Cell Dev Biol 2015; 42:103-17. [PMID: 26126935 DOI: 10.1016/j.semcdb.2015.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 06/23/2015] [Indexed: 11/19/2022]
Abstract
Models for the generation and interpretation of spatial patterns are discussed. Crucial for these processes is an intimate link between self-enhancing and antagonistic reactions. For spatial patterning, long-ranging antagonistic reactions are required that restrict the self-enhancing reactions to generate organizing regions. Self-enhancement is also required for a permanent switch-like activation of genes. This self-enhancement is antagonized by the mutual repression of genes, making sure that in a particular cell only one gene of a set of possible genes become activated - a long range inhibition in the 'gene space'. The understanding how the main body axes are initiated becomes more straightforward if the evolutionary ancestral head/brain pattern and the trunk pattern is considered separately. To activate a specific gene at particular concentration of morphogenetic gradient, observations are compatible with a systematic and time-requiring 'promotion' from one gene to the next until the local concentration is insufficient to accomplish a further promotion. The achieved determination is stable against a fading of the morphogen, as required to allow substantial growth. Minor modifications lead to a purely time-dependent activation of genes; both mechanisms are involved to pattern the anteroposterior axis. A mutual activation of cell states that locally exclude each other accounts for many features of the segmental patterning of the trunk. A possible scenario for the evolutionary invention of segmentation is discussed that is based on a reemployment of interactions involved in asexual reproduction.
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Affiliation(s)
- Hans Meinhardt
- Max-Planck-Institut für Entwicklungsbiologie, Spemannstr. 35, D-72076 Tübingen, Germany.
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