1
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Huljev K, Shamipour S, Pinheiro D, Preusser F, Steccari I, Sommer CM, Naik S, Heisenberg CP. A hydraulic feedback loop between mesendoderm cell migration and interstitial fluid relocalization promotes embryonic axis formation in zebrafish. Dev Cell 2023; 58:582-596.e7. [PMID: 36931269 DOI: 10.1016/j.devcel.2023.02.016] [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: 01/10/2022] [Revised: 08/31/2022] [Accepted: 02/20/2023] [Indexed: 03/18/2023]
Abstract
Interstitial fluid (IF) accumulation between embryonic cells is thought to be important for embryo patterning and morphogenesis. Here, we identify a positive mechanical feedback loop between cell migration and IF relocalization and find that it promotes embryonic axis formation during zebrafish gastrulation. We show that anterior axial mesendoderm (prechordal plate [ppl]) cells, moving in between the yolk cell and deep cell tissue to extend the embryonic axis, compress the overlying deep cell layer, thereby causing IF to flow from the deep cell layer to the boundary between the yolk cell and the deep cell layer, directly ahead of the advancing ppl. This IF relocalization, in turn, facilitates ppl cell protrusion formation and migration by opening up the space into which the ppl moves and, thereby, the ability of the ppl to trigger IF relocalization by pushing against the overlying deep cell layer. Thus, embryonic axis formation relies on a hydraulic feedback loop between cell migration and IF relocalization.
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Affiliation(s)
- Karla Huljev
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Shayan Shamipour
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Diana Pinheiro
- Research Institute of Molecular Pathology, Vienna Biocenter, 1030 Vienna, Austria
| | - Friedrich Preusser
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück centre for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Irene Steccari
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | | | - Suyash Naik
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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2
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Concha ML, Reig G. Origin, form and function of extraembryonic structures in teleost fishes. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210264. [PMID: 36252221 PMCID: PMC9574637 DOI: 10.1098/rstb.2021.0264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/12/2022] [Indexed: 12/18/2022] Open
Abstract
Teleost eggs have evolved a highly derived early developmental pattern within vertebrates as a result of the meroblastic cleavage pattern, giving rise to a polar stratified architecture containing a large acellular yolk and a small cellular blastoderm on top. Besides the acellular yolk, the teleost-specific yolk syncytial layer (YSL) and the superficial epithelial enveloping layer are recognized as extraembryonic structures that play critical roles throughout embryonic development. They provide enriched microenvironments in which molecular feedback loops, cellular interactions and mechanical signals emerge to sculpt, among other things, embryonic patterning along the dorsoventral and left-right axes, mesendodermal specification and the execution of morphogenetic movements in the early embryo and during organogenesis. An emerging concept points to a critical role of extraembryonic structures in reinforcing early genetic and morphogenetic programmes in reciprocal coordination with the embryonic blastoderm, providing the necessary boundary conditions for development to proceed. In addition, the role of the enveloping cell layer in providing mechanical, osmotic and immunological protection during early stages of development, and the autonomous nutritional support provided by the yolk and YSL, have probably been key aspects that have enabled the massive radiation of teleosts to colonize every ecological niche on the Earth. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'.
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Affiliation(s)
- Miguel L. Concha
- Integrative Biology Program, Institute of Biomedical Sciences (ICBM), Facultad de Medicina, Universidad de Chile, Santiago 8380453, Chile
- Biomedical Neuroscience Institute (BNI), Santiago 8380453, Chile
- Center for Geroscience, Brain Health and Metabolism (GERO), Santiago 7800003, Chile
| | - Germán Reig
- Escuela de Tecnología Médica y del Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O’Higgins, Santiago 7800003, Chile
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3
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Xing C, Zeng Z, Li Y, Gong B, Shen W, Shah R, Yan L, Du H, Meng A. Regulatory factor identification for nodal genes in zebrafish by causal inference. Front Cell Dev Biol 2022; 10:1047363. [DOI: 10.3389/fcell.2022.1047363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 10/04/2022] [Indexed: 11/13/2022] Open
Abstract
Activation of nodal genes is critical for mesoderm and endoderm induction. Our previous study reported that zebrafish nodal genes ndr1/squint and ndr2/cyclops are coordinately regulated by maternal Eomesa, Hwa-activated β-catenin (Hwa/β-catenin) signaling, and Nodal autoregulation (Nodal/Smad2) signaling. However, the exact contribution and underlying mechanisms are still elusive. Here, we applied “causal inference” to evaluate the causal between the independent and dependent variables, and we found that Hwa/β-catenin and Smad2 are the cause of ndr1 activation, while Eomesa is the cause of ndr2 activation. Mechanistically, the different cis-regulatory regions of ndr1 and ndr2 bound by Eomesa, β-catenin, and Smad2 were screened out via ChIP-qPCR and verified by the transgene constructs. The marginal GFP expression driven by ndr1 transgenesis could be diminished without both maternal Eomesa and Hwa/β-catenin, while Eomesa, not β-catenin, could bind and activate ndr2 demonstrated by ndr2 transgenesis. Thus, the distinct regulation of ndr1/ndr2 relies on different cis-regulatory regions.
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4
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Kuhn T, Landge AN, Mörsdorf D, Coßmann J, Gerstenecker J, Čapek D, Müller P, Gebhardt JCM. Single-molecule tracking of Nodal and Lefty in live zebrafish embryos supports hindered diffusion model. Nat Commun 2022; 13:6101. [PMID: 36243734 PMCID: PMC9569377 DOI: 10.1038/s41467-022-33704-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
The hindered diffusion model postulates that the movement of a signaling molecule through an embryo is affected by tissue geometry and binding-mediated hindrance, but these effects have not been directly demonstrated in vivo. Here, we visualize extracellular movement and binding of individual molecules of the activator-inhibitor signaling pair Nodal and Lefty in live developing zebrafish embryos using reflected light-sheet microscopy. We observe that diffusion coefficients of molecules are high in extracellular cavities, whereas mobility is reduced and bound fractions are high within cell-cell interfaces. Counterintuitively, molecules nevertheless accumulate in cavities, which we attribute to the geometry of the extracellular space by agent-based simulations. We further find that Nodal has a larger bound fraction than Lefty and shows a binding time of tens of seconds. Together, our measurements and simulations provide direct support for the hindered diffusion model and yield insights into the nanometer-to-micrometer-scale mechanisms that lead to macroscopic signal dispersal.
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Affiliation(s)
- Timo Kuhn
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Amit N. Landge
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - David Mörsdorf
- grid.418026.90000 0004 0492 0357Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany ,grid.10420.370000 0001 2286 1424University of Vienna, Department of Neurosciences and Developmental Biology, Djerassiplatz 1, 1030 Vienna, Austria
| | - Jonas Coßmann
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Johanna Gerstenecker
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Daniel Čapek
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Patrick Müller
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany ,grid.418026.90000 0004 0492 0357Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany
| | - J. Christof M. Gebhardt
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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5
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Xing C, Shen W, Gong B, Li Y, Yan L, Meng A. Maternal Factors and Nodal Autoregulation Orchestrate Nodal Gene Expression for Embryonic Mesendoderm Induction in the Zebrafish. Front Cell Dev Biol 2022; 10:887987. [PMID: 35693948 PMCID: PMC9178097 DOI: 10.3389/fcell.2022.887987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Nodal proteins provide crucial signals for mesoderm and endoderm induction. In zebrafish embryos, the nodal genes ndr1/squint and ndr2/cyclops are implicated in mesendoderm induction. It remains elusive how ndr1 and ndr2 expression is regulated spatiotemporally. Here we investigated regulation of ndr1 and ndr2 expression using Mhwa mutants that lack the maternal dorsal determinant Hwa with deficiency in β-catenin signaling, Meomesa mutants that lack maternal Eomesodermin A (Eomesa), Meomesa;Mhwa double mutants, and the Nodal signaling inhibitor SB431542. We show that ndr1 and ndr2 expression is completely abolished in Meomesa;Mhwa mutant embryos, indicating an essential role of maternal eomesa and hwa. Hwa-activated β-catenin signaling plays a major role in activation of ndr1 expression in the dorsal blastodermal margin, while eomesa is mostly responsible for ndr1 expression in the lateroventral margin and Nodal signaling contributes to ventral expansion of the ndr1 expression domain. However, ndr2 expression mainly depends on maternal eomesa with minor or negligible contribution of maternal hwa and Nodal autoregulation. These mechanisms may help understand regulation of Nodal expression in other species.
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Affiliation(s)
- Cencan Xing
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Daxing Research Institute, University of Science and Technology, Beijing, China
| | - Weimin Shen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bo Gong
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yaqi Li
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lu Yan
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Anming Meng
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Guangzhou National Laboratory, Guangzhou, China
- *Correspondence: Anming Meng,
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6
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Hill CS. Establishment and interpretation of NODAL and BMP signaling gradients in early vertebrate development. Curr Top Dev Biol 2022; 149:311-340. [PMID: 35606059 DOI: 10.1016/bs.ctdb.2021.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transforming growth factor β (TGF-β) family ligands play crucial roles in orchestrating early embryonic development. Most significantly, two family members, NODAL and BMP form signaling gradients and indeed in fish, frogs and sea urchins these two opposing gradients are sufficient to organize a complete embryonic axis. This review focuses on how these gradients are established and interpreted during early vertebrate development. The review highlights key principles that are emerging, in particular the importance of signaling duration as well as ligand concentration in both gradient generation and their interpretation. Feedforward and feedback loops involving other signaling pathways are also essential for providing spatial and temporal information downstream of the NODAL and BMP signaling pathways. Finally, new data suggest the existence of buffering mechanisms, whereby early signaling defects can be readily corrected downstream later in development, suggesting that signaling gradients do not have to be as precise as previously thought.
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Affiliation(s)
- Caroline S Hill
- Developmental Signalling Laboratory, The Francis Crick Institute, London, United Kingdom.
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7
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Jones WD, Mullins MC. Cell signaling pathways controlling an axis organizing center in the zebrafish. Curr Top Dev Biol 2022; 150:149-209. [DOI: 10.1016/bs.ctdb.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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8
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Marelli F, Rurale G, Persani L. From Endoderm to Progenitors: An Update on the Early Steps of Thyroid Morphogenesis in the Zebrafish. Front Endocrinol (Lausanne) 2021; 12:664557. [PMID: 34149617 PMCID: PMC8213386 DOI: 10.3389/fendo.2021.664557] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/14/2021] [Indexed: 12/24/2022] Open
Abstract
The mechanisms underlying thyroid gland development have a central interest in biology and this review is aimed to provide an update on the recent advancements on the early steps of thyroid differentiation that were obtained in the zebrafish, because this teleost fish revealed to be a suitable organism to study the early developmental stages. Physiologically, the thyroid precursors fate is delineated by the appearance among the endoderm cells of the foregut of a restricted cell population expressing specific transcription factors, including pax2a, nkx2.4b, and hhex. The committed thyroid primordium first appears as a thickening of the pharyngeal floor of the anterior endoderm, that subsequently detaches from the floor and migrates to its final location where it gives rise to the thyroid hormone-producing follicles. At variance with mammalian models, thyroid precursor differentiation in zebrafish occurs early during the developmental process before the dislocation to the eutopic positioning of thyroid follicles. Several pathways have been implicated in these early events and nowadays there is evidence of a complex crosstalk between intrinsic (coming from the endoderm and thyroid precursors) and extrinsic factors (coming from surrounding tissues, as the cardiac mesoderm) whose organization in time and space is probably required for the proper thyroid development. In particular, Notch, Shh, Fgf, Bmp, and Wnt signaling seems to be required for the commitment of endodermal cells to a thyroid fate at specific developmental windows of zebrafish embryo. Here, we summarize the recent findings produced in the various zebrafish experimental models with the aim to define a comprehensive picture of such complicated puzzle.
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Affiliation(s)
- Federica Marelli
- Dipartimento di Malattie Endocrine e del Metabolismo, IRCCS Istituto Auxologico Italiano IRCCS, Milan, Italy
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano - LITA, Segrate, Italy
| | - Giuditta Rurale
- Dipartimento di Malattie Endocrine e del Metabolismo, IRCCS Istituto Auxologico Italiano IRCCS, Milan, Italy
| | - Luca Persani
- Dipartimento di Malattie Endocrine e del Metabolismo, IRCCS Istituto Auxologico Italiano IRCCS, Milan, Italy
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano - LITA, Segrate, Italy
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9
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Reassembling gastrulation. Dev Biol 2021; 474:71-81. [DOI: 10.1016/j.ydbio.2020.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/11/2020] [Accepted: 12/13/2020] [Indexed: 12/18/2022]
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10
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Rogers KW, ElGamacy M, Jordan BM, Müller P. Optogenetic investigation of BMP target gene expression diversity. eLife 2020; 9:58641. [PMID: 33174840 PMCID: PMC7728441 DOI: 10.7554/elife.58641] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022] Open
Abstract
Signaling molecules activate distinct patterns of gene expression to coordinate embryogenesis, but how spatiotemporal expression diversity is generated is an open question. In zebrafish, a BMP signaling gradient patterns the dorsal-ventral axis. We systematically identified target genes responding to BMP and found that they have diverse spatiotemporal expression patterns. Transcriptional responses to optogenetically delivered high- and low-amplitude BMP signaling pulses indicate that spatiotemporal expression is not fully defined by different BMP signaling activation thresholds. Additionally, we observed negligible correlations between spatiotemporal expression and transcription kinetics for the majority of analyzed genes in response to BMP signaling pulses. In contrast, spatial differences between BMP target genes largely collapsed when FGF and Nodal signaling were inhibited. Our results suggest that, similar to other patterning systems, combinatorial signaling is likely to be a major driver of spatial diversity in BMP-dependent gene expression in zebrafish.
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Affiliation(s)
- Katherine W Rogers
- Systems Biology of Development Group, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
| | - Mohammad ElGamacy
- Systems Biology of Development Group, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany.,Modeling Tumorigenesis Group, Translational Oncology Division, Eberhard Karls University Tübingen, Tübingen, Germany.,Heliopolis Biotechnology Ltd, London, United Kingdom
| | - Benjamin M Jordan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, United States
| | - Patrick Müller
- Systems Biology of Development Group, Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany.,Modeling Tumorigenesis Group, Translational Oncology Division, Eberhard Karls University Tübingen, Tübingen, Germany
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11
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Wild SL, Elghajiji A, Grimaldos Rodriguez C, Weston SD, Burke ZD, Tosh D. The Canonical Wnt Pathway as a Key Regulator in Liver Development, Differentiation and Homeostatic Renewal. Genes (Basel) 2020; 11:genes11101163. [PMID: 33008122 PMCID: PMC7599793 DOI: 10.3390/genes11101163] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 02/06/2023] Open
Abstract
The canonical Wnt (Wnt/β-catenin) signalling pathway is highly conserved and plays a critical role in regulating cellular processes both during development and in adult tissue homeostasis. The Wnt/β-catenin signalling pathway is vital for correct body patterning and is involved in fate specification of the gut tube, the primitive precursor of liver. In adults, the Wnt/β-catenin pathway is increasingly recognised as an important regulator of metabolic zonation, homeostatic renewal and regeneration in response to injury throughout the liver. Herein, we review recent developments relating to the key role of the pathway in the patterning and fate specification of the liver, in the directed differentiation of pluripotent stem cells into hepatocytes and in governing proliferation and zonation in the adult liver. We pay particular attention to recent contributions to the controversy surrounding homeostatic renewal and proliferation in response to injury. Furthermore, we discuss how crosstalk between the Wnt/β-catenin and Hedgehog (Hh) and hypoxia inducible factor (HIF) pathways works to maintain liver homeostasis. Advancing our understanding of this pathway will benefit our ability to model disease, screen drugs and generate tissue and organ replacements for regenerative medicine.
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12
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Schauer A, Pinheiro D, Hauschild R, Heisenberg CP. Zebrafish embryonic explants undergo genetically encoded self-assembly. eLife 2020; 9:55190. [PMID: 32250246 PMCID: PMC7190352 DOI: 10.7554/elife.55190] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/05/2020] [Indexed: 12/20/2022] Open
Abstract
Embryonic stem cell cultures are thought to self-organize into embryoid bodies, able to undergo symmetry-breaking, germ layer specification and even morphogenesis. Yet, it is unclear how to reconcile this remarkable self-organization capacity with classical experiments demonstrating key roles for extrinsic biases by maternal factors and/or extraembryonic tissues in embryogenesis. Here, we show that zebrafish embryonic tissue explants, prepared prior to germ layer induction and lacking extraembryonic tissues, can specify all germ layers and form a seemingly complete mesendoderm anlage. Importantly, explant organization requires polarized inheritance of maternal factors from dorsal-marginal regions of the blastoderm. Moreover, induction of endoderm and head-mesoderm, which require peak Nodal-signaling levels, is highly variable in explants, reminiscent of embryos with reduced Nodal signals from the extraembryonic tissues. Together, these data suggest that zebrafish explants do not undergo bona fide self-organization, but rather display features of genetically encoded self-assembly, where intrinsic genetic programs control the emergence of order.
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13
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14
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Abstract
Soon after fertilization the zebrafish embryo generates the pool of cells that will give rise to the germline and the three somatic germ layers of the embryo (ectoderm, mesoderm and endoderm). As the basic body plan of the vertebrate embryo emerges, evolutionarily conserved developmental signaling pathways, including Bmp, Nodal, Wnt, and Fgf, direct the nearly totipotent cells of the early embryo to adopt gene expression profiles and patterns of cell behavior specific to their eventual fates. Several decades of molecular genetics research in zebrafish has yielded significant insight into the maternal and zygotic contributions and mechanisms that pattern this vertebrate embryo. This new understanding is the product of advances in genetic manipulations and imaging technologies that have allowed the field to probe the cellular, molecular and biophysical aspects underlying early patterning. The current state of the field indicates that patterning is governed by the integration of key signaling pathways and physical interactions between cells, rather than a patterning system in which distinct pathways are deployed to specify a particular cell fate. This chapter focuses on recent advances in our understanding of the genetic and molecular control of the events that impart cell identity and initiate the patterning of tissues that are prerequisites for or concurrent with movements of gastrulation.
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Affiliation(s)
- Florence L Marlow
- Icahn School of Medicine Mount Sinai Department of Cell, Developmental and Regenerative Biology, New York, NY, United States.
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15
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Zebrafish macroH2A variants have distinct embryo localization and function. Sci Rep 2019; 9:8632. [PMID: 31201343 PMCID: PMC6570772 DOI: 10.1038/s41598-019-45058-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/29/2019] [Indexed: 11/08/2022] Open
Abstract
Mouse and cell-based studies have shown that macroH2A histone variants predominantly associate with heterochromatin. Functional studies found that macroH2As are involved in gene repression, inhibiting the acquisition of pluripotency and preserving cell differentiation. However, only a few studies have analysed the role of macroH2A during early embryo development. We report the development of transgenic zebrafish lines expressing macroH2A isoforms (mH2A1 and mH2A2) fusion proteins (with GFP) under identified endogenous promoters. We found that mH2A1 and mH2A2 have different spatial and temporal expression patterns during embryonic development. mH2A1 is expressed mostly in the extraembryonic Yolk Syncytial Layer (YSL) starting before shield stage and decreasing once morphogenesis is completed. mH2A2 expression lags behind mH2A1, becoming evident at 24 hpf, within the whole body of the embryo proper. Our ChIP-seq analysis showed that mH2A1 and mH2A2 bind to different DNA regions, changing dramatically after gastrulation. We further analysed RNA-seq data and showed that there is not a general/unspecific repressing function of mH2A1 or mH2A2 associated with heterochromatin but a fine regulation depending on cell types and stage of development. mH2A1 downregulates DNA expression in specific cells and embryo stages and its effect is independent of heterochromatin formation but it is correlated with nucleus quiescence instead. Whereas mH2A2 DNA association correlates with upregulation of differentially expressed genes between 75% epiboly and 24 hpf stages. Our data provide information for underlying molecules that participate in crucial early developmental events, and open new venues to explore mH2A related mechanisms that involve cell proliferation, differentiation, migration and metabolism.
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16
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Abstract
TGF-β family ligands function in inducing and patterning many tissues of the early vertebrate embryonic body plan. Nodal signaling is essential for the specification of mesendodermal tissues and the concurrent cellular movements of gastrulation. Bone morphogenetic protein (BMP) signaling patterns tissues along the dorsal-ventral axis and simultaneously directs the cell movements of convergence and extension. After gastrulation, a second wave of Nodal signaling breaks the symmetry between the left and right sides of the embryo. During these processes, elaborate regulatory feedback between TGF-β ligands and their antagonists direct the proper specification and patterning of embryonic tissues. In this review, we summarize the current knowledge of the function and regulation of TGF-β family signaling in these processes. Although we cover principles that are involved in the development of all vertebrate embryos, we focus specifically on three popular model organisms: the mouse Mus musculus, the African clawed frog of the genus Xenopus, and the zebrafish Danio rerio, highlighting the similarities and differences between these species.
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Affiliation(s)
- Joseph Zinski
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
| | - Benjamin Tajer
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
| | - Mary C Mullins
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6058
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17
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Rogers KW, Lord ND, Gagnon JA, Pauli A, Zimmerman S, Aksel DC, Reyon D, Tsai SQ, Joung JK, Schier AF. Nodal patterning without Lefty inhibitory feedback is functional but fragile. eLife 2017; 6. [PMID: 29215332 PMCID: PMC5720593 DOI: 10.7554/elife.28785] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/07/2017] [Indexed: 12/12/2022] Open
Abstract
Developmental signaling pathways often activate their own inhibitors. Such inhibitory feedback has been suggested to restrict the spatial and temporal extent of signaling or mitigate signaling fluctuations, but these models are difficult to rigorously test. Here, we determine whether the ability of the mesendoderm inducer Nodal to activate its inhibitor Lefty is required for development. We find that zebrafish lefty mutants exhibit excess Nodal signaling and increased specification of mesendoderm, resulting in embryonic lethality. Strikingly, development can be fully restored without feedback: Lethal patterning defects in lefty mutants can be rescued by ectopic expression of lefty far from its normal expression domain or by spatially and temporally uniform exposure to a Nodal inhibitor drug. While drug-treated mutants are less tolerant of mild perturbations to Nodal signaling levels than wild type embryos, they can develop into healthy adults. These results indicate that patterning without inhibitory feedback is functional but fragile. During animal development, a single fertilized cell gives rise to different tissues and organs. This ‘patterning’ process depends on signaling molecules that instruct cells in different positions in the embryo to acquire different identities. To avoid mistakes during patterning, each cell must receive the correct amount of signal at the appropriate time. In a process called ‘inhibitory feedback’, a signaling molecule instructs cells to produce molecules that block its own signaling. Although inhibitory feedback is widely used during patterning in organisms ranging from sea urchins to mammals, its exact purpose is often not clear. In part this is because feedback is challenging to experimentally manipulate. Removing the inhibitor disrupts feedback, but also increases signaling. Since the effects of broken feedback and increased signaling are intertwined, any resulting developmental defects do not provide information about what feedback specifically does. In order to examine the role of feedback, it is therefore necessary to disconnect the production of the inhibitor from the signaling process. In developing embryos, a well-known signaling molecule called Nodal instructs cells to become specific types – for example, a heart or gut cell. Nodal also promotes the production of its inhibitor, Lefty. To understand how this feedback system works, Rogers, Lord et al. first removed Lefty from zebrafish embryos. These embryos had excessive levels of Nodal signaling, did not develop correctly, and could not survive. Bathing the embryos in a drug that inhibits Nodal reduced excess signaling and allowed them to develop successfully. In these drug-treated embryos, inhibitor production is disconnected from the signaling process, allowing the role of feedback to be examined. Drug-treated embryos were less able to tolerate fluctuations in Nodal signaling than normal zebrafish embryos, which could compensate for such disturbances by adjusting Lefty levels. Overall, it appears that inhibitory feedback in this patterning system is important to compensate for alterations in Nodal signaling, but is not essential for development. Understanding the role of inhibitory feedback will be useful for efforts to grow tissues and organs in the laboratory for clinical use. The results presented by Rogers, Lord et al. also suggest the possibility that drug treatments could be developed to help correct birth defects in the womb.
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Affiliation(s)
- Katherine W Rogers
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Nathan D Lord
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - James A Gagnon
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Andrea Pauli
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Steven Zimmerman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Deniz C Aksel
- Program in Biophysics, Harvard Medical School, Boston, United States
| | - Deepak Reyon
- Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, United States.,Department of Pathology, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States.,Center for Cancer Research, Massachusetts General Hospital, Charlestown, United States
| | - Shengdar Q Tsai
- Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, United States.,Department of Pathology, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States.,Center for Cancer Research, Massachusetts General Hospital, Charlestown, United States
| | - J Keith Joung
- Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, United States.,Department of Pathology, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States.,Center for Cancer Research, Massachusetts General Hospital, Charlestown, United States
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,Broad Institute of MIT and Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States.,Harvard Stem Cell Institute, Harvard University, Cambridge, United States.,Center for Systems Biology, Harvard University, Cambridge, United States
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18
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Tseng WC, Munisha M, Gutierrez JB, Dougan ST. Establishment of the Vertebrate Germ Layers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:307-381. [PMID: 27975275 DOI: 10.1007/978-3-319-46095-6_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The process of germ layer formation is a universal feature of animal development. The germ layers separate the cells that produce the internal organs and tissues from those that produce the nervous system and outer tissues. Their discovery in the early nineteenth century transformed embryology from a purely descriptive field into a rigorous scientific discipline, in which hypotheses could be tested by observation and experimentation. By systematically addressing the questions of how the germ layers are formed and how they generate overall body plan, scientists have made fundamental contributions to the fields of evolution, cell signaling, morphogenesis, and stem cell biology. At each step, this work was advanced by the development of innovative methods of observing cell behavior in vivo and in culture. Here, we take an historical approach to describe our current understanding of vertebrate germ layer formation as it relates to the long-standing questions of developmental biology. By comparing how germ layers form in distantly related vertebrate species, we find that highly conserved molecular pathways can be adapted to perform the same function in dramatically different embryonic environments.
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Affiliation(s)
- Wei-Chia Tseng
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Mumingjiang Munisha
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Juan B Gutierrez
- Department of Mathematics, University of Georgia, Athens, GA, 30602, USA.,Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA
| | - Scott T Dougan
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
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19
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Abstract
The zebrafish pancreas shares its basic organization and cell types with the mammalian pancreas. In addition, the developmental pathways that lead to the establishment of the pancreatic islets of Langherhans are generally conserved from fish to mammals. Zebrafish provides a powerful tool to probe the mechanisms controlling establishment of the pancreatic endocrine cell types from early embryonic progenitor cells, as well as the regeneration of endocrine cells after damage. This knowledge is, in turn, applicable to refining protocols to generate renewable sources of human pancreatic islet cells that are critical for regulation of blood sugar levels. Here, we review how previous and ongoing studies in zebrafish and beyond are influencing the understanding of molecular mechanisms underlying various forms of diabetes and efforts to develop cell-based approaches to cure this increasingly widespread disease.
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20
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Localization in Oogenesis of Maternal Regulators of Embryonic Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 953:173-207. [DOI: 10.1007/978-3-319-46095-6_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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van Boxtel AL, Chesebro JE, Heliot C, Ramel MC, Stone RK, Hill CS. A Temporal Window for Signal Activation Dictates the Dimensions of a Nodal Signaling Domain. Dev Cell 2015; 35:175-85. [PMID: 26506307 PMCID: PMC4640439 DOI: 10.1016/j.devcel.2015.09.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 08/11/2015] [Accepted: 09/23/2015] [Indexed: 11/22/2022]
Abstract
Morphogen signaling is critical for the growth and patterning of tissues in embryos and adults, but how morphogen signaling gradients are generated in tissues remains controversial. The morphogen Nodal was proposed to form a long-range signaling gradient via a reaction-diffusion system, on the basis of differential diffusion rates of Nodal and its antagonist Lefty. Here we use a specific zebrafish Nodal biosensor combined with immunofluorescence for phosphorylated Smad2 to demonstrate that endogenous Nodal is unlikely to diffuse over a long range. Instead, short-range Nodal signaling activation in a temporal window is sufficient to determine the dimensions of the Nodal signaling domain. The size of this temporal window is set by the differentially timed production of Nodal and Lefty, which arises mainly from repression of Lefty translation by the microRNA miR-430. Thus, temporal information is transformed into spatial information to define the dimensions of the Nodal signaling domain and, consequently, to specify mesendoderm.
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Affiliation(s)
- Antonius L van Boxtel
- Developmental Signalling, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - John E Chesebro
- Developmental Signalling, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Claire Heliot
- Developmental Signalling, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Marie-Christine Ramel
- Developmental Signalling, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Richard K Stone
- Experimental Histopathology, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Caroline S Hill
- Developmental Signalling, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
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22
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Abstract
The liver is a central regulator of metabolism, and liver failure thus constitutes a major health burden. Understanding how this complex organ develops during embryogenesis will yield insights into how liver regeneration can be promoted and how functional liver replacement tissue can be engineered. Recent studies of animal models have identified key signaling pathways and complex tissue interactions that progressively generate liver progenitor cells, differentiated lineages and functional tissues. In addition, progress in understanding how these cells interact, and how transcriptional and signaling programs precisely coordinate liver development, has begun to elucidate the molecular mechanisms underlying this complexity. Here, we review the lineage relationships, signaling pathways and transcriptional programs that orchestrate hepatogenesis.
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Affiliation(s)
- Miriam Gordillo
- Department of Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, New York, NY 10065, USA
| | - Valerie Gouon-Evans
- Department of Developmental and Regenerative Biology, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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23
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Gu W, Monteiro R, Zuo J, Simões FC, Martella A, Andrieu-Soler C, Grosveld F, Sauka-Spengler T, Patient R. A novel TGFβ modulator that uncouples R-Smad/I-Smad-mediated negative feedback from R-Smad/ligand-driven positive feedback. PLoS Biol 2015; 13:e1002051. [PMID: 25665164 PMCID: PMC4321984 DOI: 10.1371/journal.pbio.1002051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/17/2014] [Indexed: 01/17/2023] Open
Abstract
As some of the most widely utilised intercellular signalling molecules, transforming growth factor β (TGFβ) superfamily members play critical roles in normal development and become disrupted in human disease. Establishing appropriate levels of TGFβ signalling involves positive and negative feedback, which are coupled and driven by the same signal transduction components (R-Smad transcription factor complexes), but whether and how the regulation of the two can be distinguished are unknown. Genome-wide comparison of published ChIP-seq datasets suggests that LIM domain binding proteins (Ldbs) co-localise with R-Smads at a substantial subset of R-Smad target genes including the locus of inhibitory Smad7 (I-Smad7), which mediates negative feedback for TGFβ signalling. We present evidence suggesting that zebrafish Ldb2a binds and directly activates the I-Smad7 gene, whereas it binds and represses the ligand gene, Squint (Sqt), which drives positive feedback. Thus, the fine tuning of TGFβ signalling derives from positive and negative control by Ldb2a. Expression of ldb2a is itself activated by TGFβ signals, suggesting potential feed-forward loops that might delay the negative input of Ldb2a to the positive feedback, as well as the positive input of Ldb2a to the negative feedback. In this way, precise gene expression control by Ldb2a enables an initial build-up of signalling via a fully active positive feedback in the absence of buffering by the negative feedback. In Ldb2a-deficient zebrafish embryos, homeostasis of TGFβ signalling is perturbed and signalling is stably enhanced, giving rise to excess mesoderm and endoderm, an effect that can be rescued by reducing signalling by the TGFβ family members, Nodal and BMP. Thus, Ldb2a is critical to the homeostatic control of TGFβ signalling and thereby embryonic patterning.
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Affiliation(s)
- Wenchao Gu
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Rui Monteiro
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- BHF Centre of Research Excellence, Oxford, United Kingdom
| | - Jie Zuo
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Filipa Costa Simões
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Andrea Martella
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Charlotte Andrieu-Soler
- INSERM U872, Université René Descartes Sorbonne Paris Cité, Team 17, Centre de Recherche des Cordeliers, Paris, France
| | - Frank Grosveld
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Tatjana Sauka-Spengler
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Roger Patient
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- BHF Centre of Research Excellence, Oxford, United Kingdom
- * E-mail:
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24
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Kenyon EJ, Campos I, Bull JC, Williams PH, Stemple DL, Clark MD. Zebrafish Rab5 proteins and a role for Rab5ab in nodal signalling. Dev Biol 2014; 397:212-24. [PMID: 25478908 PMCID: PMC4294769 DOI: 10.1016/j.ydbio.2014.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 11/03/2014] [Accepted: 11/11/2014] [Indexed: 01/08/2023]
Abstract
The RAB5 gene family is the best characterised of all human RAB families and is essential for in vitro homotypic fusion of early endosomes. In recent years, the disruption or activation of Rab5 family proteins has been used as a tool to understand growth factor signal transduction in whole animal systems such as Drosophila melanogaster and zebrafish. In this study we have examined the functions for four rab5 genes in zebrafish. Disruption of rab5ab expression by antisense morpholino oligonucleotide (MO) knockdown abolishes nodal signalling in early zebrafish embryos, whereas overexpression of rab5ab mRNA leads to ectopic expression of markers that are normally downstream of nodal signalling. By contrast MO disruption of other zebrafish rab5 genes shows little or no effect on expression of markers of dorsal organiser development. We conclude that rab5ab is essential for nodal signalling and organizer specification in the developing zebrafish embryo. We have examined the activities of each of the zebrafish Rab5 genes using morpholino knockdowns. Loss of one Rab5 isoform, Rab5ab, affects formation of the dorsal organizer. Rab5ab overexpression leads to ectopic expression of dorsal markers.
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Affiliation(s)
- Emma J Kenyon
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Isabel Campos
- Champalimaud Centre for the Unknown, Fundação Champalimaud, Lisboa, Portugal
| | - James C Bull
- Department of Biosciences, Swansea University, Swansea SA2 8PP, United Kingdom
| | - P Huw Williams
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Derek L Stemple
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
| | - Matthew D Clark
- Sequencing Technology Development, The Genome Analysis Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom
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25
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Xu P, Zhu G, Wang Y, Sun J, Liu X, Chen YG, Meng A. Maternal Eomesodermin regulates zygotic nodal gene expression for mesendoderm induction in zebrafish embryos. J Mol Cell Biol 2014; 6:272-85. [DOI: 10.1093/jmcb/mju028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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26
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Webb SE, Miller AL. Calcium signaling in extraembryonic domains during early teleost development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 304:369-418. [PMID: 23809440 DOI: 10.1016/b978-0-12-407696-9.00007-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
It is becoming recognized that the extraembryonic domains of developing vertebrates, that is, those that make no cellular contribution to the embryo proper, act as important signaling centers that induce and pattern the germ layers and help establish the key embryonic axes. In the embryos of teleost fish, in particular, significant progress has been made in understanding how signaling activity in extraembryonic domains, such as the enveloping layer, the yolk syncytial layer, and the yolk cell, might help regulate development via a combination of inductive interactions, cellular dynamics, and localized gene expression. Ca(2+) signaling in a variety of forms that include propagating waves and standing gradients is a feature found in all three teleostean extraembryonic domains. This leads us to propose that in addition to their other well-characterized signaling activities, extraembryonic domains are well suited (due to their relative stability and continuity) to act as Ca(2+) signaling centers and conduits.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
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27
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Fontenille L, Rouquier S, Lutfalla G, Giorgi D. Microtubule-associated protein 9 (Map9/Asap) is required for the early steps of zebrafish development. Cell Cycle 2014; 13:1101-14. [PMID: 24553125 PMCID: PMC4013161 DOI: 10.4161/cc.27944] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Microtubules are structural components of the cell cytoskeleton and key factors for mitosis and ciliogenesis in eukaryotes. The regulation of MT dynamics requires non-motor MAPs. We previously showed that, in human cells in culture, MAP9 (also named ASAP) is involved in MT dynamics and is essential for mitotic spindle formation and mitosis progression. Indeed, misexpression of MAP9 leads to severe mitotic defects and cell death. Here, we investigated the in vivo role of map9 during zebrafish development. Map9 is expressed mainly as a maternal gene. Within cells, Map9 is associated with the MT network of the mitotic spindle and with centrosomes. Morpholino-mediated depletion of map9 leads to early development arrest before completion of epiboly. Map9 localizes to the MT array of the YSL. This MT network is destroyed in Map9-depleted embryos, and injection of anti-map9 morpholinos directly in the nascent YSL leads to arrest of epiboly/gastrulation. Finally, map9 knockdown deregulates the expression of genes involved in endodermal differentiation, dorso-ventral and left-right patterning, and other MT-based functions. At low morpholino doses, the surviving embryos show dramatic developmental defects, spindle and mitotic defects, and increased apoptosis. Our findings suggest that map9 is a crucial factor in early zebrafish development by regulating different MT-based processes.
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Affiliation(s)
- Laura Fontenille
- Institute of Human Genetics; UPR 1142; CNRS; Montpellier, France; Université de Montpellier 1; Montpellier, France
| | - Sylvie Rouquier
- Institute of Human Genetics; UPR 1142; CNRS; Montpellier, France
| | - Georges Lutfalla
- Dynamique des Interactions Membranaires Normales et Pathologiques; UMR 5235; CNRS; Universités de Montpellier 1&2; Montpellier, France
| | - Dominique Giorgi
- Institute of Human Genetics; UPR 1142; CNRS; Montpellier, France
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28
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Extraembryonic Signals under the Control of MGA, Max, and Smad4 Are Required for Dorsoventral Patterning. Dev Cell 2014; 28:322-34. [DOI: 10.1016/j.devcel.2014.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 11/13/2013] [Accepted: 01/07/2014] [Indexed: 11/19/2022]
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29
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Characterization of Ca(2+) signaling in the external yolk syncytial layer during the late blastula and early gastrula periods of zebrafish development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:1641-56. [PMID: 23142640 DOI: 10.1016/j.bbamcr.2012.10.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/26/2012] [Accepted: 10/30/2012] [Indexed: 11/24/2022]
Abstract
Preferential loading of the complementary bioluminescent (f-aequorin) and fluorescent (Calcium Green-1 dextran) Ca(2+) reporters into the yolk syncytial layer (YSL) of zebrafish embryos, revealed the generation of stochastic patterns of fast, short-range, and slow, long-range Ca(2+) waves that propagate exclusively through the external YSL (E-YSL). Starting abruptly just after doming (~4.5h post-fertilization: hpf), and ending at the shield stage (~6.0hpf) these distinct classes of waves propagated at mean velocities of ~50 and ~4μm/s, respectively. Although the number and pattern of these waves varied between embryos, their initiation site and arcs of propagation displayed a distinct dorsal bias, suggesting an association with the formation and maintenance of the nascent dorsal-ventral axis. Wave initiation coincided with a characteristic clustering of YSL nuclei (YSN), and their associated perinuclear ER, in the E-YSL. Furthermore, the inter-YSN distance (IND) appeared to be critical such that Ca(2+) wave propagation occurred only when this was <~8μm; an IND >~8μm was coincidental with wave termination at shield stage. Treatment with the IP3R antagonist, 2-APB, the Ca(2+) buffer, 5,5'-dibromo BAPTA, and the SERCA-pump inhibitor, thapsigargin, resulted in a significant disruption of the E-YSL Ca(2+) waves, whereas exposure to the RyR antagonists, ryanodine and dantrolene, had no significant effect. These findings led us to propose that the E-YSL Ca(2+) waves are generated mainly via Ca(2+) release from IP3Rs located in the perinuclear ER, and that the clustering of the YSN is an essential step in providing a CICR pathway required for wave propagation. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
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30
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Xu C, Fan ZP, Müller P, Fogley R, DiBiase A, Trompouki E, Unternaehrer J, Xiong F, Torregroza I, Evans T, Megason SG, Daley GQ, Schier AF, Young RA, Zon LI. Nanog-like regulates endoderm formation through the Mxtx2-Nodal pathway. Dev Cell 2012; 22:625-38. [PMID: 22421047 DOI: 10.1016/j.devcel.2012.01.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 09/19/2011] [Accepted: 01/11/2012] [Indexed: 12/15/2022]
Abstract
In mammalian embryonic stem cells, the acquisition of pluripotency is dependent on Nanog, but the in vivo analysis of Nanog has been hampered by its requirement for early mouse development. In an effort to examine the role of Nanog in vivo, we identified a zebrafish Nanog ortholog and found that its knockdown impaired endoderm formation. Genome-wide transcription analysis revealed that nanog-like morphants fail to develop the extraembryonic yolk syncytial layer (YSL), which produces Nodal, required for endoderm induction. We examined the genes that were regulated by Nanog-like and identified the homeobox gene mxtx2, which is both necessary and sufficient for YSL induction. Chromatin immunoprecipitation assays and genetic studies indicated that Nanog-like directly activates mxtx2, which, in turn, specifies the YSL lineage by directly activating YSL genes. Our study identifies a Nanog-like-Mxtx2-Nodal pathway and establishes a role for Nanog-like in regulating the formation of the extraembryonic tissue required for endoderm induction.
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Affiliation(s)
- Cong Xu
- Howard Hughes Medical Institute, Children's Hospital Boston and Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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31
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Narayanan A, Lekven AC. Biphasic wnt8a expression is achieved through interactions of multiple regulatory inputs. Dev Dyn 2012; 241:1062-75. [PMID: 22473868 DOI: 10.1002/dvdy.23787] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2012] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Vertebrate axis development depends upon wnt8a transcription in a dynamic pool of mesoderm progenitors at the posterior pole of the gastrulating embryo. The transcriptional mechanisms controlling wnt8a expression are not understood, but previous studies identified two phases of wnt8a expression in zebrafish: Nodal-dependent activation during early gastrulation (phase I) and No tail (Ntl)-dependent regulation from mid gastrula stages (phase II). RESULTS We identified two upstream cis-regulatory regions, proximal and distal, each of which possesses a promoter. The proximal regulatory region contains a margin-specific enhancer that is required for both the Nodal and Ntl responses. Phase I expression requires Nodal activation of the margin enhancer in combination with the transcription factor Zbtb4 and the distal regulatory region. Phase II expression requires Ntl regulation of the margin enhancer in the context of the proximal regulatory region. An additional mechanism is required to ensure the transition from phase I to phase II regulation. Analysis of stickleback wnt8a suggests this mechanism of regulation may be conserved. CONCLUSIONS The seemingly simple wnt8a expression pattern reflects complex interactions of multiple regulatory inputs.
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Affiliation(s)
- Anand Narayanan
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258, USA
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32
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Liu Z, Lin X, Cai Z, Zhang Z, Han C, Jia S, Meng A, Wang Q. Global identification of SMAD2 target genes reveals a role for multiple co-regulatory factors in zebrafish early gastrulas. J Biol Chem 2011; 286:28520-32. [PMID: 21669877 PMCID: PMC3151094 DOI: 10.1074/jbc.m111.236307] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Nodal and Smad2/3 signals play pivotal roles in mesendoderm induction and axis determination during late blastulation and early gastrulation in vertebrate embryos. However, Smad2/3 direct target genes during those critical developmental stages have not been systematically identified. Here, through ChIP-chip assay, we show that the promoter/enhancer regions of 679 genes are bound by Smad2 in the zebrafish early gastrulas. Expression analyses confirm that a significant proportion of Smad2 targets are indeed subjected to Nodal/Smad2 regulation at the onset of gastrulation. The co-existence of DNA-binding sites of other transcription factors in the Smad2-bound regions allows the identification of well known Smad2-binding partners, such as FoxH1 and Lef1/β-catenin, as well as many previously unknown Smad2 partners, including Oct1 and Gata6, during embryogenesis. We demonstrate that Oct1 physically associates with and enhances the transcription and mesendodermal induction activity of Smad2, whereas Gata6 exerts an inhibitory role in Smad2 signaling and mesendodermal induction. Thus, our study systemically uncovers a large number of Smad2 targets in early gastrulas and suggests cooperative roles of Smad2 and other transcription factors in controlling target gene transcription, which will be valuable for studying regulatory cascades during germ layer formation and patterning of vertebrate embryos.
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Affiliation(s)
- Zhaoting Liu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, China
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Nodal-dependent mesendoderm specification requires the combinatorial activities of FoxH1 and Eomesodermin. PLoS Genet 2011; 7:e1002072. [PMID: 21637786 PMCID: PMC3102743 DOI: 10.1371/journal.pgen.1002072] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 03/23/2011] [Indexed: 12/24/2022] Open
Abstract
Vertebrate mesendoderm specification requires the Nodal signaling pathway and its transcriptional effector FoxH1. However, loss of FoxH1 in several species does not reliably cause the full range of loss-of-Nodal phenotypes, indicating that Nodal signals through additional transcription factors during early development. We investigated the FoxH1-dependent and -independent roles of Nodal signaling during mesendoderm patterning using a novel recessive zebrafish FoxH1 mutation called midway, which produces a C-terminally truncated FoxH1 protein lacking the Smad-interaction domain but retaining DNA–binding capability. Using a combination of gel shift assays, Nodal overexpression experiments, and genetic epistasis analyses, we demonstrate that midway more accurately represents a complete loss of FoxH1-dependent Nodal signaling than the existing zebrafish FoxH1 mutant schmalspur. Maternal-zygotic midway mutants lack notochords, in agreement with FoxH1 loss in other organisms, but retain near wild-type expression of markers of endoderm and various nonaxial mesoderm fates, including paraxial and intermediate mesoderm and blood precursors. We found that the activity of the T-box transcription factor Eomesodermin accounts for specification of these tissues in midway embryos. Inhibition of Eomesodermin in midway mutants severely reduces the specification of these tissues and effectively phenocopies the defects seen upon complete loss of Nodal signaling. Our results indicate that the specific combinations of transcription factors available for signal transduction play critical and separable roles in determining Nodal pathway output during mesendoderm patterning. Our findings also offer novel insights into the co-evolution of the Nodal signaling pathway, the notochord specification program, and the chordate branch of the deuterostome family of animals. Multiple signaling pathways function combinatorially to form and pattern the primary tissue layers of almost all organisms, by interacting with each other and by utilizing different pathway components to perform specific roles. Here we investigated the combinatorial aspects of the Nodal signaling pathway, which is essential for proper induction of mesoderm and endoderm in vertebrates. We identified a new mutation in the zebrafish FoxH1 gene, which encodes a Nodal pathway transcription factor, a protein that responds to Nodal signals to carry out the pathway's cellular functions by regulating target gene expression. Using this mutation, we determined that FoxH1 acts in a combinatorial fashion with two other transcription factors, called Mixer and Eomesodermin, to carry out all roles of the Nodal pathway during early development. Through genetic manipulation, we were able to identify the discrete functions regulated by different combinations of these three transcription factors. Our results indicate that the availability of specific Nodal-responsive transcription factors dictates the functions of the Nodal pathway in specific areas of the developing embryo. Our work also provides evidence that the FoxH1 family of transcription factors evolved concomitantly, and perhaps causally, with the chordate branch of animals, to which all vertebrates including humans belong.
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Narayanan A, Thompson SA, Lee JJ, Lekven AC. A transgenic wnt8a:PAC reporter reveals biphasic regulation of vertebrate mesoderm development. Dev Dyn 2011; 240:898-907. [PMID: 21384472 DOI: 10.1002/dvdy.22599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2011] [Indexed: 12/25/2022] Open
Affiliation(s)
- Anand Narayanan
- Department of Biology, Texas A&M University, College Station, Texas, USA
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Hong SK, Jang MK, Brown JL, McBride AA, Feldman B. Embryonic mesoderm and endoderm induction requires the actions of non-embryonic Nodal-related ligands and Mxtx2. Development 2011; 138:787-95. [PMID: 21266414 DOI: 10.1242/dev.058974] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Vertebrate mesoderm and endoderm formation requires signaling by Nodal-related ligands from the TGFβ superfamily. The factors that initiate Nodal-related gene transcription are unknown in most species and the relative contributions of Nodal-related ligands from embryonic, extraembryonic and maternal sources remain uncertain. In zebrafish, signals from the yolk syncytial layer (YSL), an extraembryonic domain, are required for mesoderm and endoderm induction, and YSL expression of nodal-related 1 (ndr1) and ndr2 accounts for a portion of this activity. A variable requirement of maternally derived Ndr1 for dorsal and anterior axis formation has also been documented. Here we show that Mxtx2 directly activates expression of ndr2 via binding to its first intron and is required for ndr2 expression in the YSL. Mxtx2 is also required for the Nodal signaling-independent expression component of the no tail a (ntla) gene, which is required for posterior (tail) mesoderm formation. Therefore, Mxtx2 defines a new pathway upstream of Nodal signaling and posterior mesoderm formation. We further show that the co-disruption of extraembryonic Ndr2, extraembryonic Ndr1 and maternal Ndr1 eliminates endoderm and anterior (head and trunk) mesoderm, recapitulating the loss of Nodal signaling phenotype. Therefore, non-embryonic sources of Nodal-related ligands account for the complete spectrum of early Nodal signaling requirements. In summary, the induction of mesoderm and endoderm depends upon the combined actions of Mxtx2 and Nodal-related ligands from non-embryonic sources.
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Affiliation(s)
- Sung-Kook Hong
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
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Zhang T, Yao S, Wang P, Yin C, Xiao C, Qian M, Liu D, Zheng L, Meng W, Zhu H, Liu J, Xu H, Mo X. ApoA-II directs morphogenetic movements of zebrafish embryo by preventing chromosome fusion during nuclear division in yolk syncytial layer. J Biol Chem 2011; 286:9514-25. [PMID: 21212265 DOI: 10.1074/jbc.m110.134908] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The high density lipoprotein (HDL) represents a class of lipid- and protein-containing particles and consists of two major apolipoproteins apoA-I and apoA-II. ApoA-II has been shown to be involved in the pathogenesis of insulin resistance, adiposity, diabetes, and metabolic syndrome. In embryo, apoa2 mRNAs are abundant in the liver, brain, lung, placenta, and in fish yolk syncytial layer (YSL), suggesting that apoa2 may perform a function during embryonic development. Here we find out that apoa2 modulates zebrafish embryonic development by regulating the organization of YSL. Disruption of apoa2 function in zebrafish caused chromosome fusing, which strongly blocked YSL nuclear division, inducing disorders in YSL organization and finally disturbing the embryonic epiboly. Purified native human apoA-II was able specifically to rescue the defects and induced nuclear division in zebrafish embryos and in human HeLa cells. The C terminus of apoA-II was required for the proper chromosome separation during nuclear division of YSL in zebrafish embryos and in human HeLa cells. Our data indicate that organization of YSL is required for blastoderm patterning and morphogenesis and suggest that apolipoprotein apoA-II is a novel factor of nuclear division in YSL involved in the regulation of early zebrafish embryonic morphogenesis and in mammalian cells for proliferation.
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Affiliation(s)
- Ting Zhang
- Laboratory of Stem Cell Biology, West China Hospital West China Medical School, Sichuan University, Chengdu 610041, China
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Abstract
Due to the powerful combination of genetic and embryological techniques, the teleost fish Danio rerio has emerged in the last decade as an important model organism for the study of embryonic development. It is relatively easy to inject material such as mRNA or synthetic oligonucleotides to reduce or increase the expression of a gene product. Changes in gene expression can be analyzed at the level of mRNA, by whole-mount in situ hybridization, or at the level of protein, by immunofluorescence. It is also possible to quantitatively analyze protein levels by Western and immunoprecipitation. Cell behavior can be analyzed in detail by cell transplantation and by fate mapping. Because a large number of mutations have been identified in recent years, these methods can be applied in a variety of contexts to provide a deep understanding of gene function that is often more difficult to achieve in other vertebrate model systems.
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Affiliation(s)
- Yuhua Sun
- Department of Cellular Biology, The University of Georgia, Athens, GA, USA.
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The yolk syncytial layer in early zebrafish development. Trends Cell Biol 2010; 20:586-92. [DOI: 10.1016/j.tcb.2010.06.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/28/2010] [Accepted: 06/28/2010] [Indexed: 11/30/2022]
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Hong SK, Levin CS, Brown JL, Wan H, Sherman BT, Huang DW, Lempicki RA, Feldman B. Pre-gastrula expression of zebrafish extraembryonic genes. BMC DEVELOPMENTAL BIOLOGY 2010; 10:42. [PMID: 20423468 PMCID: PMC2873407 DOI: 10.1186/1471-213x-10-42] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 04/27/2010] [Indexed: 01/11/2023]
Abstract
Background Many species form extraembryonic tissues during embryogenesis, such as the placenta of humans and other viviparous mammals. Extraembryonic tissues have various roles in protecting, nourishing and patterning embryos. Prior to gastrulation in zebrafish, the yolk syncytial layer - an extraembryonic nuclear syncytium - produces signals that induce mesoderm and endoderm formation. Mesoderm and endoderm precursor cells are situated in the embryonic margin, an external ring of cells along the embryo-yolk interface. The yolk syncytial layer initially forms below the margin, in a domain called the external yolk syncytial layer (E-YSL). Results We hypothesize that key components of the yolk syncytial layer's mesoderm and endoderm inducing activity are expressed as mRNAs in the E-YSL. To identify genes expressed in the E-YSL, we used microarrays to compare the transcription profiles of intact pre-gastrula embryos with pre-gastrula embryonic cells that we had separated from the yolk and yolk syncytial layer. This identified a cohort of genes with enriched expression in intact embryos. Here we describe our whole mount in situ hybridization analysis of sixty-eight of them. This includes ten genes with E-YSL expression (camsap1l1, gata3, znf503, hnf1ba, slc26a1, slc40a1, gata6, gpr137bb, otop1 and cebpa), four genes with expression in the enveloping layer (EVL), a superficial epithelium that protects the embryo (zgc:136817, zgc:152778, slc14a2 and elovl6l), three EVL genes whose expression is transiently confined to the animal pole (elovl6l, zgc:136359 and clica), and six genes with transient maternal expression (mtf1, wu:fj59f04, mospd2, rftn2, arrdc1a and pho). We also assessed the requirement of Nodal signaling for the expression of selected genes in the E-YSL, EVL and margin. Margin expression was Nodal dependent for all genes we tested, including the concentrated margin expression of an EVL gene: zgc:110712. All other instances of EVL and E-YSL expression that we tested were Nodal independent. Conclusion We have devised an effective strategy for enriching and identifying genes expressed in the E-YSL of pre-gastrula embryos. To our surprise, maternal genes and genes expressed in the EVL were also enriched by this strategy. A number of these genes are promising candidates for future functional studies on early embryonic patterning.
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Affiliation(s)
- Sung-Kook Hong
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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40
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Abstract
The endoderm germ layer contributes to the respiratory and gastrointestinal tracts and to all of their associated organs. Over the past decade, studies in vertebrate model organisms, including frog, fish, chick, and mouse, have greatly enhanced our understanding of the molecular basis of endoderm organ development. We review this progress with a focus on early stages of endoderm organogenesis including endoderm formation, gut tube morphogenesis and patterning, and organ specification. Lastly, we discuss how developmental mechanisms that regulate endoderm organogenesis are used to direct differentiation of embryonic stem cells into specific adult cell types, which function to alleviate disease symptoms in animal models.
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Affiliation(s)
- Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children's Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45229, USA.
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Takeuchi M, Takahashi M, Okabe M, Aizawa S. Germ layer patterning in bichir and lamprey; an insight into its evolution in vertebrates. Dev Biol 2009; 332:90-102. [PMID: 19433081 DOI: 10.1016/j.ydbio.2009.05.543] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/21/2009] [Accepted: 05/05/2009] [Indexed: 11/30/2022]
Abstract
Amphibian holoblastic cleavage in which all blastomeres contribute to any one of the three primary germ layers has been widely thought to be a developmental pattern in the stem lineage of vertebrates, and meroblastic cleavage to have evolved independently in each vertebrate lineage. In extant primitive vertebrates, agnathan lamprey and basal bony fishes also undergo holoblastic cleavage, and their vegetal blastomeres have been generally thought to contribute to embryonic endoderm. However, the present marker analyses in basal ray-finned fish bichir and agnathan lamprey embryos indicated that their mesoderm and endoderm develop in the equatorial marginal zone, and their vegetal cell mass is extraembryonic nutritive yolk cells, having non-cell autonomous meso-endoderm inducing activity. Eomesodermin (eomes), but not VegT, orthologs are expressed maternally in these animals, suggesting that VegT is a maternal factor for endoderm differentiation only in amphibian. The study raises the viewpoint that the lamprey/bichir type holoblastic development would have been ancestral to extant vertebrates and retained in their stem lineage; amphibian-type holoblastic development would have been acquired secondarily, accompanied by the exploitation of new molecular machinery such as maternal VegT.
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Affiliation(s)
- Masaki Takeuchi
- Laboratory for Vertebrate Body Plan, Center for Developmental Biology, RIKEN Kobe, Hyogo 650-0047, Japan
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Chan TM, Longabaugh W, Bolouri H, Chen HL, Tseng WF, Chao CH, Jang TH, Lin YI, Hung SC, Wang HD, Yuh CH. Developmental gene regulatory networks in the zebrafish embryo. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1789:279-98. [PMID: 18992377 DOI: 10.1016/j.bbagrm.2008.09.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 08/21/2008] [Accepted: 09/22/2008] [Indexed: 01/12/2023]
Abstract
The genomic developmental program operates mainly through the regulated expression of genes encoding transcription factors and signaling pathways. Complex networks of regulatory genetic interactions control developmental cell specification and fates. Development in the zebrafish, Danio rerio, has been studied extensively and large amounts of experimental data, including information on spatial and temporal gene expression patterns, are available. A wide variety of maternal and zygotic regulatory factors and signaling pathways have been discovered in zebrafish, and these provide a useful starting point for reconstructing the gene regulatory networks (GRNs) underlying development. In this review, we describe in detail the genetic regulatory subcircuits responsible for dorsoanterior-ventroposterior patterning and endoderm formation. We describe a number of regulatory motifs, which appear to act as the functional building blocks of the GRNs. Different positive feedback loops drive the ventral and dorsal specification processes. Mutual exclusivity in dorsal-ventral polarity in zebrafish is governed by intra-cellular cross-inhibiting GRN motifs, including vent/dharma and tll1/chordin. The dorsal-ventral axis seems to be determined by competition between two maternally driven positive-feedback loops (one operating on Dharma, the other on Bmp). This is the first systematic approach aimed at developing an integrated model of the GRNs underlying zebrafish development. Comparison of GRNs' organizational motifs between different species will provide insights into developmental specification and its evolution. The online version of the zebrafish GRNs can be found at http://www.zebrafishGRNs.org.
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Affiliation(s)
- Tzu-Min Chan
- Division of Molecular and Genomic Medicine, National Health Research Institute, Taiwan, Republic of China
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Transcriptional profiling of endogenous germ layer precursor cells identifies dusp4 as an essential gene in zebrafish endoderm specification. Proc Natl Acad Sci U S A 2008; 105:12337-42. [PMID: 18719100 DOI: 10.1073/pnas.0805589105] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A major goal for developmental biologists is to define the behaviors and molecular contents of differentiating cells. We have devised a strategy for isolating cells from diverse embryonic regions and stages in the zebrafish, using computer-guided laser photoconversion of injected Kaede protein and flow cytometry. This strategy enabled us to perform a genome-wide transcriptome comparison of germ layer precursor cells. Mesendoderm and ectoderm precursors cells isolated by this method differentiated appropriately in transplantation assays. Microarray analysis of these cells reidentified known genes at least as efficiently as previously reported strategies that relied on artificial mesendoderm activation or inhibition. We also identified a large set of uncharacterized mesendoderm-enriched genes as well as ectoderm-enriched genes. Loss-of-function studies revealed that one of these genes, the MAP kinase inhibitor dusp4, is essential for early development. Embryos injected with antisense morpholino oligonucleotides that targeted Dusp4 displayed necrosis of head tissues. Marker analysis during late gastrulation revealed a specific loss of sox17, but not of other endoderm markers, and analysis at later stages revealed a loss of foregut and pancreatic endoderm. This specific loss of sox17 establishes a new class of endoderm specification defect.
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Fan X, Dougan ST. The evolutionary origin of nodal-related genes in teleosts. Dev Genes Evol 2007; 217:807-13. [PMID: 17992538 DOI: 10.1007/s00427-007-0191-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 10/10/2007] [Indexed: 11/29/2022]
Abstract
Because of an extra whole-genome duplication, zebrafish and other teleosts have two copies of genes that are present in a single copy in tetrapod genomes. Some zebrafish genes, however, are present in triplicate. For example, the nodal-related genes encode secreted proteins of the transforming growth factor beta superfamily that are required in all vertebrates to induce the mesoderm and endoderm, pattern all three germ layers, and establish the left-right axis. Zebrafish have three nodal-related genes, called ndr1/squint, ndr2/cyclops, and ndr3/southpaw. As part of an analysis of enhancer elements controlling zebrafish nodal-related gene expression, we analyzed the nodal loci in the sequenced genomes of five teleost species and four tetrapod species. Each teleost genome contains three nodal-related genes, indicating that squint, cyclops, and southpaw orthologues were present early in the teleost lineage. The genes flanking the nodal-related genes are also conserved, demonstrating a high degree of conserved synteny. Although we found little homology outside of the coding sequences in this region, pufferfish enhancer sequences work in zebrafish embryos to drive reporter gene expression in the squint expression pattern. This indicates a high degree of functional conservation of enhancer elements within the teleosts. We conclude that the ancestral squint and cyclops genes arose during the teleost-specific whole-genome duplication event and that southpaw emerged from a subsequent duplication event involving ancestral squint.
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Affiliation(s)
- Xiang Fan
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA
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