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McNamara HM, Jia BZ, Guyer A, Parot VJ, Dobbs C, Schier AF, Cohen AE, Lord ND. Optogenetic control of Nodal signaling patterns. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.11.588875. [PMID: 38645239 PMCID: PMC11030342 DOI: 10.1101/2024.04.11.588875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
A crucial step in early embryogenesis is the establishment of spatial patterns of signaling activity. Tools to perturb morphogen signals with high resolution in space and time can help reveal how embryonic cells decode these signals to make appropriate fate decisions. Here, we present new optogenetic reagents and an experimental pipeline for creaHng designer Nodal signaling patterns in live zebrafish embryos. Nodal receptors were fused to the light-sensitive heterodimerizing pair Cry2/CIB1N, and the Type II receptor was sequestered to the cytosol. The improved optoNodal2 reagents eliminate dark activity and improve response kinetics, without sacrificing dynamic range. We adapted an ultra-widefield microscopy platform for parallel light patterning in up to 36 embryos and demonstrated precise spatial control over Nodal signaling activity and downstream gene expression. Patterned Nodal activation drove precisely controlled internalization of endodermal precursors. Further, we used patterned illumination to generate synthetic signaling patterns in Nodal signaling mutants, rescuing several characteristic developmental defects. This study establishes an experimental toolkit for systematic exploration of Nodal signaling patterns in live embryos.
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Affiliation(s)
| | - Bill Z. Jia
- Department of Systems Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Alison Guyer
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Vicente J. Parot
- Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Caleb Dobbs
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Adam E. Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Nathan D. Lord
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, USA
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2
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Cheng JC, Miller AL, Webb SE. Actin-mediated endocytosis in the E-YSL helps drive epiboly in zebrafish. ZYGOTE 2023; 31:517-526. [PMID: 37533161 DOI: 10.1017/s0967199423000357] [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: 08/04/2023]
Abstract
In zebrafish, a punctate band of F-actin is reported to develop in the external yolk syncytial layer (E-YSL) during the latter part of epiboly in zebrafish embryos. Here, electron microscopy (EM) and fluorescence confocal microscopy were conducted to investigate dynamic changes in the E-YSL membrane during epiboly. Using scanning EM, we report that the surface of the E-YSL is highly convoluted, consisting of a complex interwoven network of branching membrane surface microvilli-like protrusions. The region of membrane surface protrusions was relatively wide at 30% epiboly but narrowed as epiboly progressed. This narrowing was coincident with the formation of the punctate actin band. We also demonstrated using immunogold transmission EM that actin clusters were localized at the membrane surface mainly within the protrusions as well as in deeper locations of the E-YSL. Furthermore, during the latter part of epiboly, the punctate actin band was coincident with a region of highly dynamic endocytosis. Treatment with cytochalasin B led to the disruption of the punctate actin band and the membrane surface protrusions, as well as the attenuation of endocytosis. Together, our data suggest that, in the E-YSL, the region encompassing the membrane surface protrusions and its associated punctate actin band are likely to be an integral part of the localized endocytosis, which is important for the progression of epiboly in zebrafish embryos.
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Affiliation(s)
- Jackie C Cheng
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China
| | - Andrew L Miller
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China
| | - Sarah E Webb
- The Division of Life Science and Key State Laboratory for Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, China
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3
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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: 0.5] [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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4
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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: 1.0] [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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5
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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: 2.0] [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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6
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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: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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7
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Guglielmi L, Heliot C, Kumar S, Alexandrov Y, Gori I, Papaleonidopoulou F, Barrington C, East P, Economou AD, French PMW, McGinty J, Hill CS. Smad4 controls signaling robustness and morphogenesis by differentially contributing to the Nodal and BMP pathways. Nat Commun 2021; 12:6374. [PMID: 34737283 PMCID: PMC8569018 DOI: 10.1038/s41467-021-26486-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 10/07/2021] [Indexed: 12/25/2022] Open
Abstract
The transcriptional effector SMAD4 is a core component of the TGF-β family signaling pathways. However, its role in vertebrate embryo development remains unresolved. To address this, we deleted Smad4 in zebrafish and investigated the consequences of this on signaling by the TGF-β family morphogens, BMPs and Nodal. We demonstrate that in the absence of Smad4, dorsal/ventral embryo patterning is disrupted due to the loss of BMP signaling. However, unexpectedly, Nodal signaling is maintained, but lacks robustness. This Smad4-independent Nodal signaling is sufficient for mesoderm specification, but not for optimal endoderm specification. Furthermore, using Optical Projection Tomography in combination with 3D embryo morphometry, we have generated a BMP morphospace and demonstrate that Smad4 mutants are morphologically indistinguishable from embryos in which BMP signaling has been genetically/pharmacologically perturbed. Smad4 is thus differentially required for signaling by different TGF-β family ligands, which has implications for diseases where Smad4 is mutated or deleted.
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Affiliation(s)
- Luca Guglielmi
- Developmental Signalling Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Claire Heliot
- Developmental Signalling Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Sunil Kumar
- Advanced Light Microscopy, The Francis Crick Institute, London, NW1 1AT, UK
| | - Yuriy Alexandrov
- Advanced Light Microscopy, The Francis Crick Institute, London, NW1 1AT, UK
| | - Ilaria Gori
- Developmental Signalling Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | | | - Christopher Barrington
- Bioinformatics and Biostatistics Facility, The Francis Crick Institute, London, NW1 1AT, UK
| | - Philip East
- Bioinformatics and Biostatistics Facility, The Francis Crick Institute, London, NW1 1AT, UK
| | - Andrew D Economou
- Developmental Signalling Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Paul M W French
- Department of Physics, Imperial College London, SW7 2AZ, London, UK
| | - James McGinty
- Department of Physics, Imperial College London, SW7 2AZ, London, UK
| | - Caroline S Hill
- Developmental Signalling Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.
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8
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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: 2.7] [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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9
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Cloutier JK, McMann CL, Oderberg IM, Reddien PW. activin-2 is required for regeneration of polarity on the planarian anterior-posterior axis. PLoS Genet 2021; 17:e1009466. [PMID: 33780442 PMCID: PMC8057570 DOI: 10.1371/journal.pgen.1009466] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/20/2021] [Accepted: 03/03/2021] [Indexed: 01/16/2023] Open
Abstract
Planarians are flatworms and can perform whole-body regeneration. This ability involves a mechanism to distinguish between anterior-facing wounds that require head regeneration and posterior-facing wounds that require tail regeneration. How this head-tail regeneration polarity decision is made is studied to identify principles underlying tissue-identity specification in regeneration. We report that inhibition of activin-2, which encodes an Activin-like signaling ligand, resulted in the regeneration of ectopic posterior-facing heads following amputation. During tissue turnover in uninjured planarians, positional information is constitutively expressed in muscle to maintain proper patterning. Positional information includes Wnts expressed in the posterior and Wnt antagonists expressed in the anterior. Upon amputation, several wound-induced genes promote re-establishment of positional information. The head-versus-tail regeneration decision involves preferential wound induction of the Wnt antagonist notum at anterior-facing over posterior-facing wounds. Asymmetric activation of notum represents the earliest known molecular distinction between head and tail regeneration, yet how it occurs is unknown. activin-2 RNAi animals displayed symmetric wound-induced activation of notum at anterior- and posterior-facing wounds, providing a molecular explanation for their ectopic posterior-head phenotype. activin-2 RNAi animals also displayed anterior-posterior (AP) axis splitting, with two heads appearing in anterior blastemas, and various combinations of heads and tails appearing in posterior blastemas. This was associated with ectopic nucleation of anterior poles, which are head-tip muscle cells that facilitate AP and medial-lateral (ML) pattern at posterior-facing wounds. These findings reveal a role for Activin signaling in determining the outcome of AP-axis-patterning events that are specific to regeneration. A central problem in animal regeneration is how animals determine what body part to regenerate. Planarians are flatworms that can regenerate any missing body region, and are studied to identify mechanisms underlying regeneration. At transverse amputation planes, a poorly understood mechanism specifies regeneration of either a head or a tail. This head-versus-tail regeneration decision-making process is referred to as regeneration polarity and has been studied for over a century to identify mechanisms that specify what to regenerate. The gene notum, which encodes a Wnt antagonist, is induced within hours after injury preferentially at anterior-facing wounds, where it specifies head regeneration. We report that Activin signaling is required for regeneration polarity, and the underlying asymmetric activation of notum at anterior- over posterior-facing wounds. We propose that Activin signaling is involved in regeneration-specific responses broadly in the animal kingdom.
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Affiliation(s)
- Jennifer K. Cloutier
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Chevy Chase, MD, United States of America
- Harvard/MIT MD-PhD, Harvard Medical School, Boston, MA, United States of America
| | - Conor L. McMann
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Chevy Chase, MD, United States of America
| | - Isaac M. Oderberg
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Chevy Chase, MD, United States of America
| | - Peter W. Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Chevy Chase, MD, United States of America
- * E-mail:
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10
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Isthmin1, a secreted signaling protein, acts downstream of diverse embryonic patterning centers in development. Cell Tissue Res 2020; 383:987-1002. [PMID: 33367974 PMCID: PMC7960586 DOI: 10.1007/s00441-020-03318-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/06/2020] [Indexed: 11/25/2022]
Abstract
Extracellular signals play essential roles during embryonic patterning by providing positional information in a concentration-dependent manner, and many such signals, like Wnt, fibroblast growth factor (FGF), Hedgehog (Hh), and retinoic acid, act by being secreted into the extracellular space, thereby triggering receptor-mediated responses in other cells. Isthmin1 (ism1) is a secreted protein whose gene expression pattern coincides with that of early dorsal determinants, nodal ligand genes like sqt and cyc, and with fgf8 during various phases of zebrafish development. Ism1 functions in early embryonic patterning and development are poorly understood; however, it has recently been shown to interact with nodal pathway genes to control organ asymmetry in chicken. Here, we show that misexpression of ism1 deletion constructs disrupts embryonic patterning in zebrafish and exhibits genetic interactions with both Fgf and nodal signaling. Unlike Fgf and nodal pathway mutants, CRISPR/Cas9-engineered ism1 mutants did not show obvious developmental defects. Further, in vivo single molecule fluorescence correlation spectroscopy (FCCS) showed that Ism1 diffuses freely in the extra-cellular space, with a diffusion coefficient similar to that of Fgf8a; however, our measurements do not support direct molecular interactions between Ism1 and either nodal ligands or Fgf8a in the developing zebrafish embryo. Together, data from gain- and loss-of-function experiments suggest that zebrafish Ism1 plays a complex role in regulating extracellular signals during early embryonic development.
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11
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Chen JW, Niu X, King MJ, Noedl MT, Tabin CJ, Galloway JL. The mevalonate pathway is a crucial regulator of tendon cell specification. Development 2020; 147:dev.185389. [PMID: 32467241 DOI: 10.1242/dev.185389] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 05/04/2020] [Indexed: 12/20/2022]
Abstract
Tendons and ligaments are crucial components of the musculoskeletal system, yet the pathways specifying these fates remain poorly defined. Through a screen of known bioactive chemicals in zebrafish, we identified a new pathway regulating tendon cell induction. We established that statin, through inhibition of the mevalonate pathway, causes an expansion of the tendon progenitor population. Co-expression and live imaging studies indicate that the expansion does not involve an increase in cell proliferation, but rather results from re-specification of cells from the neural crest-derived sox9a+/sox10+ skeletal lineage. The effect on tendon cell expansion is specific to the geranylgeranylation branch of the mevalonate pathway and is mediated by inhibition of Rac activity. This work establishes a novel role for the mevalonate pathway and Rac activity in regulating specification of the tendon lineage.
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Affiliation(s)
- Jessica W Chen
- Center for Regenerative Medicine, Harvard Stem Cell Institute, Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Xubo Niu
- Center for Regenerative Medicine, Harvard Stem Cell Institute, Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Matthew J King
- Center for Regenerative Medicine, Harvard Stem Cell Institute, Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Marie-Therese Noedl
- Center for Regenerative Medicine, Harvard Stem Cell Institute, Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
| | - Clifford J Tabin
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Jenna L Galloway
- Center for Regenerative Medicine, Harvard Stem Cell Institute, Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114, USA
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12
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Abstract
Gastrulation is a critical early morphogenetic process of animal development, during which the three germ layers; mesoderm, endoderm and ectoderm, are rearranged by internalization movements. Concurrent epiboly movements spread and thin the germ layers while convergence and extension movements shape them into an anteroposteriorly elongated body with head, trunk, tail and organ rudiments. In zebrafish, gastrulation follows the proliferative and inductive events that establish the embryonic and extraembryonic tissues and the embryonic axis. Specification of these tissues and embryonic axes are controlled by the maternal gene products deposited in the egg. These early maternally controlled processes need to generate sufficient cell numbers and establish the embryonic polarity to ensure normal gastrulation. Subsequently, after activation of the zygotic genome, the zygotic gene products govern mesoderm and endoderm induction and germ layer patterning. Gastrulation is initiated during the maternal-to-zygotic transition, a process that entails both activation of the zygotic genome and downregulation of the maternal transcripts. Genomic studies indicate that gastrulation is largely controlled by the zygotic genome. Nonetheless, genetic studies that investigate the relative contributions of maternal and zygotic gene function by comparing zygotic, maternal and maternal zygotic mutant phenotypes, reveal significant contribution of maternal gene products, transcripts and/or proteins, that persist through gastrulation, to the control of gastrulation movements. Therefore, in zebrafish, the maternally expressed gene products not only set the stage for, but they also actively participate in gastrulation morphogenesis.
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Affiliation(s)
- Lilianna Solnica-Krezel
- Department of Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States.
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13
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Williams ML, Solnica-Krezel L. Nodal and planar cell polarity signaling cooperate to regulate zebrafish convergence and extension gastrulation movements. eLife 2020; 9:54445. [PMID: 32319426 PMCID: PMC7250581 DOI: 10.7554/elife.54445] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 04/21/2020] [Indexed: 12/14/2022] Open
Abstract
During vertebrate gastrulation, convergence and extension (C and E) of the primary anteroposterior (AP) embryonic axis is driven by polarized mediolateral (ML) cell intercalations and is influenced by AP axial patterning. Nodal signaling is essential for patterning of the AP axis while planar cell polarity (PCP) signaling polarizes cells with respect to this axis, but how these two signaling systems interact during C and E is unclear. We find that the neuroectoderm of Nodal-deficient zebrafish gastrulae exhibits reduced C and E cell behaviors, which require Nodal signaling in both cell- and non-autonomous fashions. PCP signaling is partially active in Nodal-deficient embryos and its inhibition exacerbates their C and E defects. Within otherwise naïve zebrafish blastoderm explants, however, Nodal induces C and E in a largely PCP-dependent manner, arguing that Nodal acts both upstream of and in parallel with PCP during gastrulation to regulate embryonic axis extension cooperatively.
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Affiliation(s)
- Margot Lk Williams
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Lilianna Solnica-Krezel
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
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14
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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: 30] [Impact Index Per Article: 7.5] [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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15
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Yang F, Qi J. miR-430a regulates the development of left-right asymmetry by targeting sqt in the teleost. Gene 2020; 745:144628. [PMID: 32224271 DOI: 10.1016/j.gene.2020.144628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 10/24/2022]
Abstract
microRNAs (miRNAs) are short, endogenous non-coding RNAs that contain approximately 18-22 nucleotides. miRNAs are involved in gene regulation by recognizing and binding the 3'UTR of target gene. In our previous data, miR-430 family showed significant differential expression modes through metamorphosis in Japanese flounder. It was speculated that miR-430a plays a key role in left-right patterning. We predicted the targets of miR-430a and gene ontology (GO) was performed. We speculated miR-430a is involved in the basal molecular function and organ development. In Japanese flounder, sqt as a target of miR-430a was enriched into heart development term. Sqt has been reported to participate in mesendoderm formation and organ development. Cardiac morphogenesis is the first asymmetric development process, which breaks left-right symmetry in bilateria. It was used as a marker to detect L-R asymmetric effects of miR-430a. Overexpression and suppression of miR-430a resulted in abnormal KV (Kupffer's vesicles) development and disordered in nodal-related expression with consequent cardiac laterality. Squint mRNA of Japanese flounder (Posqt) as a target of miR-430a was overexpressed and caused similar phenotype with miR-430a suppression group, such as longer cilia in KV and high range of clmc2 and spaw ectopic expression. Moreover, rescue experiments were performed and suggested that cardiac and KV defections, induced by overexpressing miR-430a, could be rescued by injecting Posqt mRNA. These results suggested that miR-430a regulates the development of left-right asymmetry by targeting sqt in the teleost.
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Affiliation(s)
- Fan Yang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Jie Qi
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
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16
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Miletto Petrazzini ME, Sovrano VA, Vallortigara G, Messina A. Brain and Behavioral Asymmetry: A Lesson From Fish. Front Neuroanat 2020; 14:11. [PMID: 32273841 PMCID: PMC7113390 DOI: 10.3389/fnana.2020.00011] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/05/2020] [Indexed: 11/27/2022] Open
Abstract
It is widely acknowledged that the left and right hemispheres of human brains display both anatomical and functional asymmetries. For more than a century, brain and behavioral lateralization have been considered a uniquely human feature linked to language and handedness. However, over the past decades this idea has been challenged by an increasing number of studies describing structural asymmetries and lateralized behaviors in non-human species extending from primates to fish. Evidence suggesting that a similar pattern of brain lateralization occurs in all vertebrates, humans included, has allowed the emergence of different model systems to investigate the development of brain asymmetries and their impact on behavior. Among animal models, fish have contributed much to the research on lateralization as several fish species exhibit lateralized behaviors. For instance, behavioral studies have shown that the advantages of having an asymmetric brain, such as the ability of simultaneously processing different information and perform parallel tasks compensate the potential costs associated with poor integration of information between the two hemispheres thus helping to better understand the possible evolutionary significance of lateralization. However, these studies inferred how the two sides of the brains are differentially specialized by measuring the differences in the behavioral responses but did not allow to directly investigate the relation between anatomical and functional asymmetries. With respect to this issue, in recent years zebrafish has become a powerful model to address lateralization at different level of complexity, from genes to neural circuitry and behavior. The possibility of combining genetic manipulation of brain asymmetries with cutting-edge in vivo imaging technique and behavioral tests makes the zebrafish a valuable model to investigate the phylogeny and ontogeny of brain lateralization and its relevance for normal brain function and behavior.
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Affiliation(s)
| | - Valeria Anna Sovrano
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.,Department of Psychology and Cognitive Science, University of Trento, Rovereto, Italy
| | | | - Andrea Messina
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
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17
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Economou AD, Hill CS. Temporal dynamics in the formation and interpretation of Nodal and BMP morphogen gradients. Curr Top Dev Biol 2019; 137:363-389. [PMID: 32143749 DOI: 10.1016/bs.ctdb.2019.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
One of the most powerful ideas in developmental biology has been that of the morphogen gradient. In the classical view, a signaling molecule is produced at a local source from where it diffuses, resulting in graded levels across the tissue. This gradient provides positional information, with thresholds in the level of the morphogen determining the position of different cell fates. While experimental studies have uncovered numerous potential morphogens in biological systems, it is becoming increasingly apparent that one important feature, not captured in the simple model, is the role of time in both the formation and interpretation of morphogen gradients. We will focus on two members of the transforming growth factor-β family that are known to play a vital role as morphogens in early vertebrate development: the Nodals and the bone morphogenetic proteins (BMPs). Primarily drawing on the early zebrafish embryo, we will show how recent studies have demonstrated the importance of feedback and other interactions that evolve through time, in shaping morphogen gradients. We will further show how rather than simply reading out levels of a morphogen, the duration of ligand exposure can be a crucial determinant of how cells interpret morphogens, in particular through the unfolding of downstream transcriptional events and in their interactions with other pathways.
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Affiliation(s)
- Andrew D Economou
- Developmental Signalling Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Caroline S Hill
- Developmental Signalling Laboratory, The Francis Crick Institute, London, United Kingdom.
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18
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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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19
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Liu Z, Woo S, Weiner OD. Nodal signaling has dual roles in fate specification and directed migration during germ layer segregation in zebrafish. Development 2018; 145:dev.163535. [PMID: 30111654 DOI: 10.1242/dev.163535] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/30/2018] [Indexed: 12/21/2022]
Abstract
During gastrulation, endodermal cells actively migrate to the interior of the embryo, but the signals that initiate and coordinate this migration are poorly understood. By transplanting ectopically induced endodermal cells far from the normal location of endoderm specification, we identified the inputs that drive internalization without the confounding influences of fate specification and global morphogenic movements. We find that Nodal signaling triggers an autocrine circuit for initiating endodermal internalization. Activation of the Nodal receptor directs endodermal specification through sox32 and also induces expression of more Nodal ligands. These ligands act in an autocrine fashion to initiate endodermal cell sorting. Our work defines an 'AND' gate consisting of sox32-dependent endodermal specification and Nodal ligand reception controlling endodermal cell sorting to the inner layer of the embryo at the onset of gastrulation.
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Affiliation(s)
- Zairan Liu
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stephanie Woo
- Department of Molecular Cell Biology, School of Natural Sciences, University of California, Merced, CA 95343, USA
| | - Orion D Weiner
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA .,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
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20
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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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21
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Ogasawara S. Duration Control of Protein Expression in Vivo by Light-Mediated Reversible Activation of Translation. ACS Chem Biol 2017; 12:351-356. [PMID: 28049292 DOI: 10.1021/acschembio.6b00684] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The photocontrol of protein expression enables the spatiotemporal induction of biological events in living cells or organisms. However, commonly used method such as photocontrollable transcription factor or caged nucleic acids is unsuitable for precise control of the duration of protein expression. Here, I report a photocontrollable cap (PC-cap) that can control the translation of mRNA in a reversible manner via its cis-trans photoisomerization through illumination with 370 and 430 nm light. 2-meta-Methyl-phenylazo cap (mMe-2PA-cap) in the trans form silences translation in zebrafish embryo, whereas treatment with the cis form provided a 7.1 times larger amount of translated protein compared to the trans form. Moreover, translation activated by illumination of the embryo with 370 nm light was rapidly inactivated again by subsequent illumination with 430 nm light. An application of this approach was demonstrated by photoinducing the development of double-headed zebrafish by controlling the expression period of squint protein.
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Affiliation(s)
- Shinzi Ogasawara
- Creative Research Institution
Sousei, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8
Honcho, Kawaguchi, Saitama 332-0012, Japan
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22
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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: 1.4] [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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23
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Houston DW. Vertebrate Axial Patterning: From Egg to Asymmetry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:209-306. [PMID: 27975274 PMCID: PMC6550305 DOI: 10.1007/978-3-319-46095-6_6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The emergence of the bilateral embryonic body axis from a symmetrical egg has been a long-standing question in developmental biology. Historical and modern experiments point to an initial symmetry-breaking event leading to localized Wnt and Nodal growth factor signaling and subsequent induction and formation of a self-regulating dorsal "organizer." This organizer forms at the site of notochord cell internalization and expresses primarily Bone Morphogenetic Protein (BMP) growth factor antagonists that establish a spatiotemporal gradient of BMP signaling across the embryo, directing initial cell differentiation and morphogenesis. Although the basics of this model have been known for some time, many of the molecular and cellular details have only recently been elucidated and the extent that these events remain conserved throughout vertebrate evolution remains unclear. This chapter summarizes historical perspectives as well as recent molecular and genetic advances regarding: (1) the mechanisms that regulate symmetry-breaking in the vertebrate egg and early embryo, (2) the pathways that are activated by these events, in particular the Wnt pathway, and the role of these pathways in the formation and function of the organizer, and (3) how these pathways also mediate anteroposterior patterning and axial morphogenesis. Emphasis is placed on comparative aspects of the egg-to-embryo transition across vertebrates and their evolution. The future prospects for work regarding self-organization and gene regulatory networks in the context of early axis formation are also discussed.
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Affiliation(s)
- Douglas W Houston
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA, 52242, USA.
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24
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Sampath K, Robertson EJ. Keeping a lid on nodal: transcriptional and translational repression of nodal signalling. Open Biol 2016; 6:150200. [PMID: 26791244 PMCID: PMC4736825 DOI: 10.1098/rsob.150200] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nodal is an evolutionarily conserved member of the transforming growth factor-β (TGF-β) superfamily of secreted signalling factors. Nodal factors are known to play key roles in embryonic development and asymmetry in a variety of organisms ranging from hydra and sea urchins to fish, mice and humans. In addition to embryonic patterning, Nodal signalling is required for maintenance of human embryonic stem cell pluripotency and mis-regulated Nodal signalling has been found associated with tumour metastases. Therefore, precise and timely regulation of this pathway is essential. Here, we discuss recent evidence from sea urchins, frogs, fish, mice and humans that show a role for transcriptional and translational repression of Nodal signalling during early development.
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Affiliation(s)
- Karuna Sampath
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AJ, UK
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25
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Sampath K, Ephrussi A. CncRNAs: RNAs with both coding and non-coding roles in development. Development 2016; 143:1234-41. [PMID: 27095489 DOI: 10.1242/dev.133298] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
RNAs are known to regulate diverse biological processes, either as protein-encoding molecules or as non-coding RNAs. However, a third class that comprises RNAs endowed with both protein coding and non-coding functions has recently emerged. Such bi-functional 'coding and non-coding RNAs' (cncRNAs) have been shown to play important roles in distinct developmental processes in plants and animals. Here, we discuss key examples of cncRNAs and review their roles, regulation and mechanisms of action during development.
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Affiliation(s)
- Karuna Sampath
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AJ, UK
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, Heidelberg 69117, Germany
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26
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Wang Y, Wang X, Wohland T, Sampath K. Extracellular interactions and ligand degradation shape the nodal morphogen gradient. eLife 2016; 5. [PMID: 27101364 PMCID: PMC4887204 DOI: 10.7554/elife.13879] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/20/2016] [Indexed: 01/19/2023] Open
Abstract
The correct distribution and activity of secreted signaling proteins called morphogens is required for many developmental processes. Nodal morphogens play critical roles in embryonic axis formation in many organisms. Models proposed to generate the Nodal gradient include diffusivity, ligand processing, and a temporal activation window. But how the Nodal morphogen gradient forms in vivo remains unclear. Here, we have measured in vivo for the first time, the binding affinity of Nodal ligands to their major cell surface receptor, Acvr2b, and to the Nodal inhibitor, Lefty, by fluorescence cross-correlation spectroscopy. We examined the diffusion coefficient of Nodal ligands and Lefty inhibitors in live zebrafish embryos by fluorescence correlation spectroscopy. We also investigated the contribution of ligand degradation to the Nodal gradient. We show that ligand clearance via degradation shapes the Nodal gradient and correlates with its signaling range. By computational simulations of gradient formation, we demonstrate that diffusivity, extra-cellular interactions, and selective ligand destruction collectively shape the Nodal morphogen gradient. DOI:http://dx.doi.org/10.7554/eLife.13879.001 Animals develop from a single fertilized egg cell into multicellular organisms. This process requires chemical signals called “morphogens” that instruct the cells how to behave during development. The morphogens move across cells and tissues to form gradients of the signal. Cells then respond in different ways depending on how much of the signal they receive. This, in turn, depends on several factors: first, how quickly or slowly the signal moves; second, how well the morphogen binds to responding cells and other molecules in its path; and third, how much signal is lost or destroyed during the movement. Many researchers study morphogen gradients in the transparent zebrafish, since it grows quickly and it is easy to see developmental changes. However, until now it was not fully clear how the well-known morphogen called Nodal moves in live zebrafish as they develop. Wang, Wang et al. have now investigated how well Nodal signals bind to the surface of cells that receive the signal and to a molecule called “Lefty”, which is present in the same path and interferes with Nodal signals. Advanced techniques called fluorescence correlation and cross-correlation spectroscopy were used to measure Nodal signals at the level of single molecules in growing zebrafish. The experiments gave insights into how far Nodal signals move and remain active. The results showed that, in addition to Nodal diffusing and binding to receiving cells, one of the most important factors determining how far and quickly Nodal moves is its inactivation and destruction. Lastly, Wang, Wang et al. built computational models to test their observations from live zebrafish. The current work was based on forcing zebrafish to produce molecules including Nodal at locations within the fish that normally do not make them. Therefore future experiments will aim to examine these molecules and their interactions when they are produced at their normal locations in the animal over time. DOI:http://dx.doi.org/10.7554/eLife.13879.002
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Affiliation(s)
- Yin Wang
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Xi Wang
- Department of Chemistry, Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Department of Chemistry, Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore
| | - Karuna Sampath
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
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27
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Langdon YG, Fuentes R, Zhang H, Abrams EW, Marlow FL, Mullins MC. Split top: a maternal cathepsin B that regulates dorsoventral patterning and morphogenesis. Development 2016; 143:1016-28. [PMID: 26893345 PMCID: PMC4813285 DOI: 10.1242/dev.128900] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 01/29/2016] [Indexed: 12/28/2022]
Abstract
The vertebrate embryonic dorsoventral axis is established and patterned by Wnt and bone morphogenetic protein (BMP) signaling pathways, respectively. Whereas Wnt signaling establishes the dorsal side of the embryo and induces the dorsal organizer, a BMP signaling gradient patterns tissues along the dorsoventral axis. Early Wnt signaling is provided maternally, whereas BMP ligand expression in the zebrafish is zygotic, but regulated by maternal factors. Concomitant with BMP activity patterning dorsoventral axial tissues, the embryo also undergoes dramatic morphogenetic processes, including the cell movements of gastrulation, epiboly and dorsal convergence. Although the zygotic regulation of these cell migration processes is increasingly understood, far less is known of the maternal regulators of these processes. Similarly, the maternal regulation of dorsoventral patterning, and in particular the maternal control of ventral tissue specification, is poorly understood. We identified split top, a recessive maternal-effect zebrafish mutant that disrupts embryonic patterning upstream of endogenous BMP signaling. Embryos from split top mutant females exhibit a dorsalized embryonic axis, which can be rescued by BMP misexpression or by derepressing endogenous BMP signaling. In addition to dorsoventral patterning defects, split top mutants display morphogenesis defects that are both BMP dependent and independent. These morphogenesis defects include incomplete dorsal convergence, delayed epiboly progression and an early lysis phenotype during gastrula stages. The latter two morphogenesis defects are associated with disruption of the actin and microtubule cytoskeleton within the yolk cell and defects in the outer enveloping cell layer, which are both known mediators of epiboly movements. Through chromosomal mapping and RNA sequencing analysis, we identified the lysosomal endopeptidase cathepsin Ba (ctsba) as the gene deficient in split top embryos. Our results identify a novel role for Ctsba in morphogenesis and expand our understanding of the maternal regulation of dorsoventral patterning.
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Affiliation(s)
- Yvette G Langdon
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA Millsaps College, Department of Biology, Jackson, MS 39210, USA
| | - Ricardo Fuentes
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Hong Zhang
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Elliott W Abrams
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Florence L Marlow
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Mary C Mullins
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
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28
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Ellis PS, Burbridge S, Soubes S, Ohyama K, Ben-Haim N, Chen C, Dale K, Shen MM, Constam D, Placzek M. ProNodal acts via FGFR3 to govern duration of Shh expression in the prechordal mesoderm. Development 2015; 142:3821-32. [PMID: 26417042 PMCID: PMC4712875 DOI: 10.1242/dev.119628] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 09/15/2015] [Indexed: 11/20/2022]
Abstract
The secreted glycoprotein sonic hedgehog (Shh) is expressed in the prechordal mesoderm, where it plays a crucial role in induction and patterning of the ventral forebrain. Currently little is known about how Shh is regulated in prechordal tissue. Here we show that in the embryonic chick, Shh is expressed transiently in prechordal mesoderm, and is governed by unprocessed Nodal. Exposure of prechordal mesoderm microcultures to Nodal-conditioned medium, the Nodal inhibitor CerS, or to an ALK4/5/7 inhibitor reveals that Nodal is required to maintain both Shh and Gsc expression, but whereas Gsc is largely maintained through canonical signalling, Nodal signals through a non-canonical route to maintain Shh. Further, Shh expression can be maintained by a recombinant Nodal cleavage mutant, proNodal, but not by purified mature Nodal. A number of lines of evidence suggest that proNodal acts via FGFR3. ProNodal and FGFR3 co-immunoprecipitate and proNodal increases FGFR3 tyrosine phosphorylation. In microcultures, soluble FGFR3 abolishes Shh without affecting Gsc expression. Further, prechordal mesoderm cells in which Fgfr3 expression is reduced by Fgfr3 siRNA fail to bind to proNodal. Finally, targeted electroporation of Fgfr3 siRNA to prechordal mesoderm in vivo results in premature Shh downregulation without affecting Gsc. We report an inverse correlation between proNodal-FGFR3 signalling and pSmad1/5/8, and show that proNodal-FGFR3 signalling antagonises BMP-mediated pSmad1/5/8 signalling, which is poised to downregulate Shh. Our studies suggest that proNodal/FGFR3 signalling governs Shh duration by repressing canonical BMP signalling, and that local BMPs rapidly silence Shh once endogenous Nodal-FGFR3 signalling is downregulated. Highlighted article: In the chick prechordal mesoderm, the Nodal precursor proNodal acts via a non-canonical route to inhibit BMP signalling and thus maintain Shh expression
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Affiliation(s)
- Pamela S Ellis
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Sarah Burbridge
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Sandrine Soubes
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Kyoji Ohyama
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Nadav Ben-Haim
- ISREC, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Epalinges CH 1066, Switzerland
| | - Canhe Chen
- Departments of Medicine and Genetics & Development, Columbia University Medical Center, Herbert Irving Comprehensive Cancer Center, 1130 St. Nicholas Avenue, New York, NY 10032, USA Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Kim Dale
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Michael M Shen
- Departments of Medicine and Genetics & Development, Columbia University Medical Center, Herbert Irving Comprehensive Cancer Center, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Daniel Constam
- ISREC, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Epalinges CH 1066, Switzerland
| | - Marysia Placzek
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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29
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Li-Villarreal N, Forbes MM, Loza AJ, Chen J, Ma T, Helde K, Moens CB, Shin J, Sawada A, Hindes AE, Dubrulle J, Schier AF, Longmore GD, Marlow FL, Solnica-Krezel L. Dachsous1b cadherin regulates actin and microtubule cytoskeleton during early zebrafish embryogenesis. Development 2015; 142:2704-18. [PMID: 26160902 DOI: 10.1242/dev.119800] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 06/25/2015] [Indexed: 01/04/2023]
Abstract
Dachsous (Dchs), an atypical cadherin, is an evolutionarily conserved regulator of planar cell polarity, tissue size and cell adhesion. In humans, DCHS1 mutations cause pleiotropic Van Maldergem syndrome. Here, we report that mutations in zebrafish dchs1b and dchs2 disrupt several aspects of embryogenesis, including gastrulation. Unexpectedly, maternal zygotic (MZ) dchs1b mutants show defects in the earliest developmental stage, egg activation, including abnormal cortical granule exocytosis (CGE), cytoplasmic segregation, cleavages and maternal mRNA translocation, in transcriptionally quiescent embryos. Later, MZdchs1b mutants exhibit altered dorsal organizer and mesendodermal gene expression, due to impaired dorsal determinant transport and Nodal signaling. Mechanistically, MZdchs1b phenotypes can be explained in part by defective actin or microtubule networks, which appear bundled in mutants. Accordingly, disruption of actin cytoskeleton in wild-type embryos phenocopied MZdchs1b mutant defects in cytoplasmic segregation and CGE, whereas interfering with microtubules in wild-type embryos impaired dorsal organizer and mesodermal gene expression without perceptible earlier phenotypes. Moreover, the bundled microtubule phenotype was partially rescued by expressing either full-length Dchs1b or its intracellular domain, suggesting that Dchs1b affects microtubules and some developmental processes independent of its known ligand Fat. Our results indicate novel roles for vertebrate Dchs in actin and microtubule cytoskeleton regulation in the unanticipated context of the single-celled embryo.
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Affiliation(s)
- Nanbing Li-Villarreal
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Meredyth M Forbes
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Andrew J Loza
- Department of Internal Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Jiakun Chen
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Taylur Ma
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Kathryn Helde
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Cecilia B Moens
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jimann Shin
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Atsushi Sawada
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Anna E Hindes
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Julien Dubrulle
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Gregory D Longmore
- Department of Internal Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Florence L Marlow
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Lilianna Solnica-Krezel
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
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30
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Tuazon FB, Mullins MC. Temporally coordinated signals progressively pattern the anteroposterior and dorsoventral body axes. Semin Cell Dev Biol 2015; 42:118-33. [PMID: 26123688 PMCID: PMC4562868 DOI: 10.1016/j.semcdb.2015.06.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/16/2015] [Indexed: 10/23/2022]
Abstract
The vertebrate body plan is established through the precise spatiotemporal coordination of morphogen signaling pathways that pattern the anteroposterior (AP) and dorsoventral (DV) axes. Patterning along the AP axis is directed by posteriorizing signals Wnt, fibroblast growth factor (FGF), Nodal, and retinoic acid (RA), while patterning along the DV axis is directed by bone morphogenetic proteins (BMP) ventralizing signals. This review addresses the current understanding of how Wnt, FGF, RA and BMP pattern distinct AP and DV cell fates during early development and how their signaling mechanisms are coordinated to concomitantly pattern AP and DV tissues.
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Affiliation(s)
- Francesca B Tuazon
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, 1152 BRBII/III, 421 Curie Boulevard, Philadelphia, PA 19104-6058, United States
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, 1152 BRBII/III, 421 Curie Boulevard, Philadelphia, PA 19104-6058, United States.
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31
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Wyatt C, Bartoszek EM, Yaksi E. Methods for studying the zebrafish brain: past, present and future. Eur J Neurosci 2015; 42:1746-63. [PMID: 25900095 DOI: 10.1111/ejn.12932] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 01/16/2023]
Abstract
The zebrafish (Danio rerio) is one of the most promising new model organisms. The increasing popularity of this amazing small vertebrate is evident from the exponentially growing numbers of research articles, funded projects and new discoveries associated with the use of zebrafish for studying development, brain function, human diseases and screening for new drugs. Thanks to the development of novel technologies, the range of zebrafish research is constantly expanding with new tools synergistically enhancing traditional techniques. In this review we will highlight the past and present techniques which have made, and continue to make, zebrafish an attractive model organism for various fields of biology, with a specific focus on neuroscience.
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Affiliation(s)
- Cameron Wyatt
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium
| | - Ewelina M Bartoszek
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Emre Yaksi
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,KU Leuven, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
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32
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Larraguibel J, Weiss ARE, Pasula DJ, Dhaliwal RS, Kondra R, Van Raay TJ. Wnt ligand-dependent activation of the negative feedback regulator Nkd1. Mol Biol Cell 2015; 26:2375-84. [PMID: 25904337 PMCID: PMC4462952 DOI: 10.1091/mbc.e14-12-1648] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/16/2015] [Indexed: 02/02/2023] Open
Abstract
Nkd1, a negative feedback regulator of the Wnt pathway, localizes with Dvl2 to the putative Wnt signalosome, where it becomes activated by Wnt. Activated Nkd1 moves away from the membrane to become more cytosolic, where it interacts with β-catenin to prevent nuclear accumulation. Misregulation of Wnt signaling is at the root of many diseases, most notably colorectal cancer, and although we understand the activation of the pathway, we have a very poor understanding of the circumstances under which Wnt signaling turns itself off. There are numerous negative feedback regulators of Wnt signaling, but two stand out as constitutive and obligate Wnt-induced regulators: Axin2 and Nkd1. Whereas Axin2 behaves similarly to Axin in the destruction complex, Nkd1 is more enigmatic. Here we use zebrafish blastula cells that are responsive Wnt signaling to demonstrate that Nkd1 activity is specifically dependent on Wnt ligand activation of the receptor. Furthermore, our results support the hypothesis that Nkd1 is recruited to the Wnt signalosome with Dvl2, where it becomes activated to move into the cytoplasm to interact with β-catenin, inhibiting its nuclear accumulation. Comparison of these results with Nkd function in Drosophila generates a unified and conserved model for the role of this negative feedback regulator in the modulation of Wnt signaling.
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Affiliation(s)
- Jahdiel Larraguibel
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Alexander R E Weiss
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Daniel J Pasula
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Rasmeet S Dhaliwal
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Roman Kondra
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Terence J Van Raay
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Abstract
Activin/Nodal growth factors control a broad range of biological processes, including early cell fate decisions, organogenesis and adult tissue homeostasis. Here, we provide an overview of the mechanisms by which the Activin/Nodal signalling pathway governs stem cell function in these different stages of development. We describe recent findings that associate Activin/Nodal signalling to pathological conditions, focusing on cancer stem cells in tumorigenesis and its potential as a target for therapies. Moreover, we will discuss future directions and questions that currently remain unanswered on the role of Activin/Nodal signalling in stem cell self-renewal, differentiation and proliferation.
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Affiliation(s)
- Siim Pauklin
- Anne McLaren Laboratory For Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, West Forvie Building, Robinson Way, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Ludovic Vallier
- Anne McLaren Laboratory For Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, West Forvie Building, Robinson Way, University of Cambridge, Cambridge CB2 0SZ, UK
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34
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Godard BG, Coolen M, Le Panse S, Gombault A, Ferreiro-Galve S, Laguerre L, Lagadec R, Wincker P, Poulain J, Da Silva C, Kuraku S, Carre W, Boutet A, Mazan S. Mechanisms of endoderm formation in a cartilaginous fish reveal ancestral and homoplastic traits in jawed vertebrates. Biol Open 2014; 3:1098-107. [PMID: 25361580 PMCID: PMC4232768 DOI: 10.1242/bio.20148037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In order to gain insight into the impact of yolk increase on endoderm development, we have analyzed the mechanisms of endoderm formation in the catshark S. canicula, a species exhibiting telolecithal eggs and a distinct yolk sac. We show that in this species, endoderm markers are expressed in two distinct tissues, the deep mesenchyme, a mesenchymal population of deep blastomeres lying beneath the epithelial-like superficial layer, already specified at early blastula stages, and the involuting mesendoderm layer, which appears at the blastoderm posterior margin at the onset of gastrulation. Formation of the deep mesenchyme involves cell internalizations from the superficial layer prior to gastrulation, by a movement suggestive of ingressions. These cell movements were observed not only at the posterior margin, where massive internalizations take place prior to the start of involution, but also in the center of the blastoderm, where internalizations of single cells prevail. Like the adjacent involuting mesendoderm, the posterior deep mesenchyme expresses anterior mesendoderm markers under the control of Nodal/activin signaling. Comparisons across vertebrates support the conclusion that endoderm is specified in two distinct temporal phases in the catshark as in all major osteichthyan lineages, in line with an ancient origin of a biphasic mode of endoderm specification in gnathostomes. They also highlight unexpected similarities with amniotes, such as the occurrence of cell ingressions from the superficial layer prior to gastrulation. These similarities may correspond to homoplastic traits fixed separately in amniotes and chondrichthyans and related to the increase in egg yolk mass.
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Affiliation(s)
- Benoit G Godard
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7150, 29688 Roscoff, France
| | - Marion Coolen
- Université d'Orléans-CNRS, UMR 6218, 45070 Orléans, France Present address: CNRS UPR 3294, Institute of Neurobiology Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - Sophie Le Panse
- Plateforme d'Imagerie, Sorbonne Universités, UPMC Univ Paris 06, CNRS, FR 2424, Station Biologique, 29688 Roscoff, France
| | - Aurélie Gombault
- Université d'Orléans-CNRS, UMR 6218, 45070 Orléans, France Present address: UMR 7355, Université d'Orleans-CNRS, 45071 Orléans, France
| | - Susana Ferreiro-Galve
- Université d'Orléans-CNRS, UMR 6218, 45070 Orléans, France Present address: Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Campus San Juan de Alicante, 03550 Alicante, Spain
| | - Laurent Laguerre
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7150, 29688 Roscoff, France
| | - Ronan Lagadec
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7150, 29688 Roscoff, France
| | - Patrick Wincker
- CEA-Institut de Génomique-Genoscope, 2 rue Gaston-Crémieux, 91057 Evry, France
| | - Julie Poulain
- CEA-Institut de Génomique-Genoscope, 2 rue Gaston-Crémieux, 91057 Evry, France
| | - Corinne Da Silva
- CEA-Institut de Génomique-Genoscope, 2 rue Gaston-Crémieux, 91057 Evry, France
| | - Shigehiro Kuraku
- Genome Resource and Analysis Unit (GRAS), Center for Developmental Biology, RIKEN.2-2-3 Minatojima-minami, Chuo-KU, Kobe 650-0047, Japan
| | - Wilfrid Carre
- ABiMS, Sorbonne Universités, UPMC Univ Paris 06, CNRS, FR 2424, 29688 Roscoff, France
| | - Agnès Boutet
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7150, 29688 Roscoff, France
| | - Sylvie Mazan
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7150, 29688 Roscoff, France
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Terashima AV, Mudumana SP, Drummond IA. Odd skipped related 1 is a negative feedback regulator of nodal-induced endoderm development. Dev Dyn 2014; 243:1571-80. [PMID: 25233796 DOI: 10.1002/dvdy.24191] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 09/03/2014] [Accepted: 09/10/2014] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Early embryo patterning is orchestrated by tightly regulated morphogen gradients. The Nodal morphogen patterns the mesendoderm, giving rise to all endoderm and head and trunk mesoderm. High Nodal concentrations favor endoderm differentiation while lower promote mesoderm differentiation. Nodal signaling is controlled by both positive and negative feedback regulation to ensure robust developmental patterning. RESULTS Here we identify odd skipped related 1 (osr1), a zinc finger transcription factor, as a new element in Nodal feedback regulation affecting endoderm development. We show that osr1 expression in zebrafish germ ring mesendoderm requires Nodal signaling; osr1 expression was lost in embryos lacking Nodal signaling. Conversely, osr1 expression was ectopically induced by the activation of Nodal signaling. Furthermore we demonstrate that osr1 responds directly to Nodal signaling. Additionally, osr1 knockdown generated excess endoderm cells marked by sox32 expression while expression of osr1 mRNA was not affected in sox32-deficient embryos. CONCLUSIONS Our findings identify osr1 as a Nodal-induced, negative feedback regulator of Nodal signaling that acts at the earliest stages of endoderm differentiation to limit the number of endoderm progenitors. As such, we propose that osr1 represents a novel network motif controlling the output of Nodal signaling to regulate mesendoderm patterning.
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36
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Nelson AC, Cutty SJ, Niini M, Stemple DL, Flicek P, Houart C, Bruce AEE, Wardle FC. Global identification of Smad2 and Eomesodermin targets in zebrafish identifies a conserved transcriptional network in mesendoderm and a novel role for Eomesodermin in repression of ectodermal gene expression. BMC Biol 2014; 12:81. [PMID: 25277163 PMCID: PMC4206766 DOI: 10.1186/s12915-014-0081-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Indexed: 12/27/2022] Open
Abstract
Background Nodal signalling is an absolute requirement for normal mesoderm and endoderm formation in vertebrate embryos, yet the transcriptional networks acting directly downstream of Nodal and the extent to which they are conserved is largely unexplored, particularly in vivo. Eomesodermin also plays a role in patterning mesoderm and endoderm in vertebrates, but its mechanisms of action and how it interacts with the Nodal signalling pathway are still unclear. Results Using a combination of expression analysis and chromatin immunoprecipitation with deep sequencing (ChIP-seq) we identify direct targets of Smad2, the effector of Nodal signalling in blastula stage zebrafish embryos, including many novel target genes. Through comparison of these data with published ChIP-seq data in human, mouse and Xenopus we show that the transcriptional network driven by Smad2 in mesoderm and endoderm is conserved in these vertebrate species. We also show that Smad2 and zebrafish Eomesodermin a (Eomesa) bind common genomic regions proximal to genes involved in mesoderm and endoderm formation, suggesting Eomesa forms a general component of the Smad2 signalling complex in zebrafish. Combinatorial perturbation of Eomesa and Smad2-interacting factor Foxh1 results in loss of both mesoderm and endoderm markers, confirming the role of Eomesa in endoderm formation and its functional interaction with Foxh1 for correct Nodal signalling. Finally, we uncover a novel role for Eomesa in repressing ectodermal genes in the early blastula. Conclusions Our data demonstrate that evolutionarily conserved developmental functions of Nodal signalling occur through maintenance of the transcriptional network directed by Smad2. This network is modulated by Eomesa in zebrafish which acts to promote mesoderm and endoderm formation in combination with Nodal signalling, whilst Eomesa also opposes ectoderm gene expression. Eomesa, therefore, regulates the formation of all three germ layers in the early zebrafish embryo. Electronic supplementary material The online version of this article (doi:10.1186/s12915-014-0081-5) contains supplementary material, which is available to authorized users.
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37
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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: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Kang N, Won M, Rhee M, Ro H. Siah ubiquitin ligases modulate nodal signaling during zebrafish embryonic development. Mol Cells 2014; 37:389-98. [PMID: 24823357 PMCID: PMC4044310 DOI: 10.14348/molcells.2014.0032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 03/27/2014] [Accepted: 03/31/2014] [Indexed: 01/15/2023] Open
Abstract
Siah2 is a zebrafish homologue of mammalian Siah family. Siah acts as an E3 ubiquitin ligase that binds proteins destined for degradation. Extensive homology between siah and Drosophila Siah homologue (sina) suggests their important physiological roles during embryonic development. However, detailed functional studies of Siah in vertebrate development have not been carried out. Here we report that Siah2 specifically augments nodal related gene expression in marginal blastomeres at late blastula through early gastrula stages of zebrafish embryos. Siah2 dependent Nodal signaling augmentation is confirmed by cell-based reporter gene assays using 293T cells and 3TPluciferase reporter plasmid. We also established a molecular hierarchy of Siah as a upstream regulator of FoxH1/Fast1 transcriptional factor in Nodal signaling. Elevated expression of nodal related genes by overexpression of Siah2 was enough to override the inhibitory effects of atv and lft2 on the Nodal signaling. In particular, E3 ubiquitin ligase activity of Siah2 is critical to limit the duration and/or magnitude of Nodal signaling. Additionally, since the embryos injected with Siah morpholinos mimicked the atv overexpression phenotype at least in part, our data support a model in which Siah is involved in mesendoderm patterning via modulating Nodal signaling.
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Affiliation(s)
- Nami Kang
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
| | - Minho Won
- Program in Genomics of Differentiation, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland,
USA
| | - Myungchull Rhee
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
| | - Hyunju Ro
- Department of Biological Sciences, College of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764,
Korea
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39
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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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40
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Kumari P, Gilligan PC, Lim S, Tran LD, Winkler S, Philp R, Sampath K. An essential role for maternal control of Nodal signaling. eLife 2013; 2:e00683. [PMID: 24040511 PMCID: PMC3771576 DOI: 10.7554/elife.00683] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 08/06/2013] [Indexed: 12/26/2022] Open
Abstract
Growth factor signaling is essential for pattern formation, growth, differentiation, and maintenance of stem cell pluripotency. Nodal-related signaling factors are required for axis formation and germ layer specification from sea urchins to mammals. Maternal transcripts of the zebrafish Nodal factor, Squint (Sqt), are localized to future embryonic dorsal. The mechanisms by which maternal sqt/nodal RNA is localized and regulated have been unclear. Here, we show that maternal control of Nodal signaling via the conserved Y box-binding protein 1 (Ybx1) is essential. We identified Ybx1 via a proteomic screen. Ybx1 recognizes the 3’ untranslated region (UTR) of sqt RNA and prevents premature translation and Sqt/Nodal signaling. Maternal-effect mutations in zebrafish ybx1 lead to deregulated Nodal signaling, gastrulation failure, and embryonic lethality. Implanted Nodal-coated beads phenocopy ybx1 mutant defects. Thus, Ybx1 prevents ectopic Nodal activity, revealing a new paradigm in the regulation of Nodal signaling, which is likely to be conserved. DOI:http://dx.doi.org/10.7554/eLife.00683.001 In many organisms, embryonic development is controlled in part by RNAs that are deposited into the egg as it forms inside the mother. These ‘maternal RNAs’ may localize to particular regions of the egg or embryo, where they are then exclusively translated into protein and carry out their specific function. This helps to establish asymmetry in the developing organism—that is, to produce tissues that will eventually become the top or bottom, front or back, and left or right of the organism. One such maternal RNA encodes Nodal, a key signaling molecule that is conserved across vertebrate and some invertebrate organisms. In zebrafish, the equivalent RNA is called squint, and plays an important role in embryonic development. The squint RNA deposited by the mother localizes to the dorsal region—the embryo’s back—and signals that region to make dorsal tissues, but how squint is regulated is not well understood. Now, Kumari et al. identify a protein that controls the positioning of squint RNA, and find that it can also prevent this RNA from being translated into protein. The squint RNA contains a ‘dorsal localization element’ that recruits it to the dorsal cells of the embryo by the 4-cell stage (i.e., within two cell divisions after the egg is fertilized). Kumari et al. identified a protein called Ybx1 that could bind to this element: this protein may help to correctly position RNAs in many other organisms, including fruit flies and mammals. Strikingly, embryos formed abnormally when their maternally derived Ybx1 protein was mutant, and these mutations also prevented the squint RNA from localizing properly. This suggests that maternally derived Ybx1 protein directly regulates the squint RNA. As well as positioning the squint RNA correctly, the embryo must translate this RNA into protein at the right time. In embryos with mutant maternal Ybx1 protein, the Squint protein could be detected at the 16-cell stage, whereas in wild-type embryos this protein is not translated until the 256-cell stage; this indicates that Ybx1 protein might normally repress the translation of the squint RNA. Indeed, Kumari et al. found that Ybx1 binds to another protein—eIF4E—that recruits mRNAs to the ribosome (the cell’s translational machinery). Ybx1 might therefore prevent eIF4E from associating with other components of the ribosomal complex, and initiating the translation of the squint RNA, until additional signals have been received. It will be interesting to determine how widespread this regulatory mechanism is in other organisms. DOI:http://dx.doi.org/10.7554/eLife.00683.002
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Affiliation(s)
- Pooja Kumari
- Temasek Life Sciences Laboratory , National University of Singapore , Singapore , Singapore ; Department of Biological Sciences , National University of Singapore , Singapore , Singapore
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41
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Lin CY, Lee HC, Chen HC, Hsieh CC, Tsai HJ. Normal function of Myf5 during gastrulation is required for pharyngeal arch cartilage development in zebrafish embryos. Zebrafish 2013; 10:486-99. [PMID: 23992145 DOI: 10.1089/zeb.2013.0903] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Myf5, a myogenic regulatory factor, plays a key role in regulating muscle differentiation. However, it is not known if Myf5 has a regulatory role during early embryogenesis. Here, we used myf5-morpholino oligonucleotides [MO] to knock down myf5 expression and demonstrated a series of results pointing to the functional roles of Myf5 during early embryogenesis: (1) reduced head size resulting from abnormal morphology in the cranial skeleton; (2) decreased expressions of the cranial neural crest (CNC) markers foxd3, sox9a, dlx2, and col2a1; (3) defect in the chondrogenic neural crest similar to that of fgf3 morphants; (4) reduced fgf3/fgf8 transcripts in the cephalic mesoderm rescued by co-injection of myf5 wobble-mismatched mRNA together with myf5-MO1 during 12 h postfertilization; (5) abnormal patterns of axial and non-axial mesoderm causing expansion of the dorsal organizer, and (6) increased bmp4 gradient, but reduced fgf3/fgf8 marginal gradient, during gastrulation. Interestingly, overexpression of fgf3 could rescue the cranial cartilage defects caused by myf5-MO1, suggesting that Myf5 modulates craniofacial cartilage development through the fgf3 signaling pathway. Together, the loss of Myf5 function results in a cascade effect that begins with abnormal formation of the dorsal organizer during gastrulation, causing, in turn, defects in the CNC and cranial cartilage of myf5-knockdown embryos.
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Affiliation(s)
- Cheng-Yung Lin
- Institute of Molecular and Cellular Biology, National Taiwan University , Taipei, Taiwan
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42
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Angonin D, Van Raay TJ. Nkd1 functions as a passive antagonist of Wnt signaling. PLoS One 2013; 8:e74666. [PMID: 24009776 PMCID: PMC3756965 DOI: 10.1371/journal.pone.0074666] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 08/05/2013] [Indexed: 12/22/2022] Open
Abstract
Wnt signaling is involved in many aspects of development and in the homeostasis of stem cells. Its importance is underscored by the fact that misregulation of Wnt signaling has been implicated in numerous diseases, especially colorectal cancer. However, how Wnt signaling regulates itself is not well understood. There are several Wnt negative feedback regulators, which are active antagonists of Wnt signaling, but one feedback regulator, Nkd1, has reduced activity compared to other antagonists, yet is still a negative feedback regulator. Here we describe our efforts to understand the role of Nkd1 using Wnt signaling compromised zebrafish mutant lines. In several of these lines, Nkd1 function was not any more active than it was in wild type embryos. However, we found that Nkd1’s ability to antagonize canonical Wnt/β-catenin signaling was enhanced in the Wnt/Planar Cell Polarity mutants silberblick (slb/wnt11) and trilobite (tri/vangl2). While slb and tri mutants do not display alterations in canonical Wnt signaling, we found that they are hypersensitive to it. Overexpression of the canonical Wnt/β-catenin ligand Wnt8a in slb or tri mutants resulted in dorsalized embryos, with tri mutants being much more sensitive to Wnt8a than slb mutants. Furthermore, the hyperdorsalization caused by Wnt8a in tri could be rescued by Nkd1. These results suggest that Nkd1 functions as a passive antagonist of Wnt signaling, functioning only when homeostatic levels of Wnt signaling have been breached or when Wnt signaling becomes destabilized.
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Affiliation(s)
- Diane Angonin
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Terence J. Van Raay
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
- * E-mail:
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43
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Full transcriptome analysis of early dorsoventral patterning in zebrafish. PLoS One 2013; 8:e70053. [PMID: 23922899 PMCID: PMC3726443 DOI: 10.1371/journal.pone.0070053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 06/14/2013] [Indexed: 11/20/2022] Open
Abstract
Understanding the molecular interactions that lead to the establishment of the major body axes during embryogenesis is one of the main goals of developmental biology. Although the past two decades have revolutionized our knowledge about the genetic basis of these patterning processes, the list of genes involved in axis formation is unlikely to be complete. In order to identify new genes involved in the establishment of the dorsoventral (DV) axis during early stages of zebrafish embryonic development, we employed next generation sequencing for full transcriptome analysis of normal embryos and embryos lacking overt DV pattern. A combination of different statistical approaches yielded 41 differentially expressed candidate genes and we confirmed by in situ hybridization the early dorsal expression of 32 genes that are transcribed shortly after the onset of zygotic transcription. Although promoter analysis of the validated genes suggests no general enrichment for the binding sites of early acting transcription factors, most of these genes carry “bivalent” epigenetic histone modifications at the time when zygotic transcription is initiated, suggesting a “poised” transcriptional status. Our results reveal some new candidates of the dorsal gene regulatory network and suggest that a plurality of the earliest upregulated genes on the dorsal side have a role in the modulation of the canonical Wnt pathway.
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Hashiguchi M, Mullins MC. Anteroposterior and dorsoventral patterning are coordinated by an identical patterning clock. Development 2013; 140:1970-80. [PMID: 23536566 DOI: 10.1242/dev.088104] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Establishment of the body plan in vertebrates depends on the temporally coordinated patterning of tissues along the body axes. We have previously shown that dorsoventral (DV) tissues are temporally patterned progressively from anterior to posterior by a BMP signaling pathway. Here we report that DV patterning along the zebrafish anteroposterior (AP) axis is temporally coordinated with AP patterning by an identical patterning clock. We altered AP patterning by inhibiting or activating FGF, Wnt or retinoic acid signaling combined with inhibition of BMP signaling at a series of developmental time points, which revealed that the temporal progression of DV patterning is directly coordinated with AP patterning. We investigated how these signaling pathways are integrated and suggest a model for how DV and AP patterning are temporally coordinated. It has been shown that in Xenopus dorsal tissues FGF and Wnt signaling quell BMP signaling by degrading phosphorylated (P) Smad1/5, the BMP pathway signal transducer, via phosphorylation of the Smad1/5 linker region. We show that in zebrafish FGF/MAPK, but not Wnt/GSK3, phosphorylation of the Smad1/5 linker region localizes to a ventral vegetal gastrula region that could coordinate DV patterning with AP patterning ventrally without degrading P-Smad1/5. Furthermore, we demonstrate that alteration of the MAPK phosphorylation sites in the Smad5 linker causes precocious patterning of DV tissues along the AP axis during gastrulation. Thus, DV and AP patterning are intimately coordinated to allow cells to acquire both positional and temporal information simultaneously.
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Affiliation(s)
- Megumi Hashiguchi
- Department of Cell and Developmental Biology, University of Pennsylvania, Perelman School of Medicine, 421 Curie Blvd., Philadelphia, PA 19104-6058, USA
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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: 1.3] [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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Lim S, Kumari P, Gilligan P, Quach HNB, Mathavan S, Sampath K. Dorsal activity of maternal squint is mediated by a non-coding function of the RNA. Development 2012; 139:2903-15. [PMID: 22721777 DOI: 10.1242/dev.077081] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Despite extensive study, the earliest steps of vertebrate axis formation are only beginning to be elucidated. We previously showed that asymmetric localization of maternal transcripts of the conserved zebrafish TGFβ factor Squint (Sqt) in 4-cell stage embryos predicts dorsal, preceding nuclear accumulation of β-catenin. Cell ablations and antisense oligonucleotides that deplete Sqt lead to dorsal deficiencies, suggesting that localized maternal sqt functions in dorsal specification. However, based upon analysis of sqt and Nodal signaling mutants, the function and mechanism of maternal sqt was debated. Here, we show that sqt RNA may function independently of Sqt protein in dorsal specification. sqt insertion mutants express localized maternal sqt RNA. Overexpression of mutant/non-coding sqt RNA and, particularly, the sqt 3'UTR, leads to ectopic nuclear β-catenin accumulation and expands dorsal gene expression. Dorsal activity of sqt RNA requires Wnt/β-catenin but not Oep-dependent Nodal signaling. Unexpectedly, sqt ATG morpholinos block both sqt RNA localization and translation and abolish nuclear β-catenin, providing a mechanism for the loss of dorsal identity in sqt morphants and placing maternal sqt RNA upstream of β-catenin. The loss of early dorsal gene expression can be rescued by the sqt 3'UTR. Our findings identify new non-coding functions for the Nodal genes and support a model wherein sqt RNA acts as a scaffold to bind and deliver/sequester maternal factors to future embryonic dorsal.
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Affiliation(s)
- Shimin Lim
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
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Du S, Draper BW, Mione M, Moens CB, Bruce AEE. Differential regulation of epiboly initiation and progression by zebrafish Eomesodermin A. Dev Biol 2012; 362:11-23. [PMID: 22142964 PMCID: PMC3259739 DOI: 10.1016/j.ydbio.2011.10.036] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/24/2011] [Accepted: 10/19/2011] [Indexed: 01/07/2023]
Abstract
The T-box transcription factor Eomesodermin (Eomes) has been implicated in patterning and morphogenesis in frog, fish and mouse. In zebrafish, one of the two Eomes homologs, Eomesa, has been implicated in dorsal-ventral patterning, epiboly and endoderm specification in experiments employing over-expression, dominant-negative constructs and antisense morpholino oligonucleotides. Here we report for the first time the identification and characterization of an Eomesa mutant generated by TILLING. We find that Eomesa has a strictly maternal role in the initiation of epiboly, which involves doming of the yolk cell up into the overlying blastoderm. By contrast, epiboly progression is normal, demonstrating for the first time that epiboly initiation is genetically separable from progression. The yolk cell microtubules, which are required for epiboly, are defective in maternal-zygotic eomesa mutant embryos. In addition, the deep cells of the blastoderm are more tightly packed and exhibit more bleb-like protrusions than cells in control embryos. We postulate that the doming delay may be the consequence both of overly stabilized yolk cell microtubules and defects in the adhesive properties or motility of deep cells. We also show that Eomesa is required for normal expression of the endoderm markers sox32, bon and og9x; however it is not essential for endoderm formation.
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Affiliation(s)
- Susan Du
- Department of Cell and Systems Biology University of Toronto 25 Harbord Street Toronto, ON M5S 3G5 Canada
| | - Bruce W. Draper
- Molecular and Cellular Biology University of California, Davis One Shields Avenue Davis, CA 95616 USA
| | - Marina Mione
- IFOM, Istituto FIRC di Oncologia Molecolare Via Adamello 16 Milan, I-20139 Italy
| | - Cecilia B. Moens
- Howard Hughes Medical Institute Division of Basic Science Fred Hutchinson Cancer Research Center P.O. Box 19024 1100 Fairview Avenue North Seattle, WA 98109-1024 USA
| | - Ashley E. E. Bruce
- Department of Cell and Systems Biology University of Toronto 25 Harbord Street Toronto, ON M5S 3G5 Canada
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Lindemann S, Senkler J, Auchter E, Liang JO. Using zebrafish to learn statistical analysis and Mendelian genetics. Zebrafish 2011; 8:41-55. [PMID: 21682600 DOI: 10.1089/zeb.2010.0686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This project was developed to promote understanding of how mathematics and statistical analysis are used as tools in genetic research. It gives students the opportunity to carry out hypothesis-driven experiments in the classroom: students generate hypotheses about Mendelian and non-Mendelian inheritance patterns, gather raw data, and test their hypotheses using chi-square statistical analysis. In the first protocol, students are challenged to analyze inheritance patterns using GloFish, brightly colored, commercially available, transgenic zebrafish that express Green, Yellow, or Red Fluorescent Protein throughout their muscles. In the second protocol, students learn about genetic screens, microscopy, and developmental biology by analyzing the inheritance patterns of mutations that cause developmental defects. The difficulty of the experiments can be adapted for middle school to upper level undergraduate students. Since the GloFish experiments use only fish and materials that can be purchased from pet stores, they should be accessible to many schools. For each protocol, we provide detailed instructions, ideas for how the experiments fit into an undergraduate curriculum, raw data, and example analyses. Our plan is to have these protocols form the basis of a growing and adaptable educational tool available on the Zebrafish in the Classroom Web site.
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Affiliation(s)
- Samantha Lindemann
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812, USA
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Abstract
Vertebrate development begins with precise molecular, cellular, and morphogenetic controls to establish the basic body plan of the embryo. In zebrafish, these tightly regulated processes begin during oogenesis and proceed through gastrulation to establish and pattern the axes of the embryo. During oogenesis a maternal factor is localized to the vegetal pole of the oocyte that is a determinant of dorsal tissues. Following fertilization this vegetally localized dorsal determinant is asymmetrically translocated in the egg and initiates formation of the dorsoventral axis. Dorsoventral axis formation and patterning is then mediated by maternal and zygotic factors acting through Wnt, BMP (bone morphogenetic protein), Nodal, and FGF (fibroblast growth factor) signaling pathways, each of which is required to establish and/or pattern the dorsoventral axis. This review addresses recent advances in our understanding of the molecular factors and mechanisms that establish and pattern the dorsoventral axis of the zebrafish embryo, including establishment of the animal-vegetal axis as it relates to formation of the dorsoventral axis.
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Affiliation(s)
- Yvette G Langdon
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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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: 3.8] [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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