1
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Azbazdar Y, De Robertis EM. Molecular analysis of a self-organizing signaling pathway for Xenopus axial patterning from egg to tailbud. Proc Natl Acad Sci U S A 2024; 121:e2408346121. [PMID: 38968117 PMCID: PMC11252917 DOI: 10.1073/pnas.2408346121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 06/06/2024] [Indexed: 07/07/2024] Open
Abstract
Xenopus embryos provide a favorable material to dissect the sequential steps that lead to dorsal-ventral (D-V) and anterior-posterior (A-P) cell differentiation. Here, we analyze the signaling pathways involved in this process using loss-of-function and gain-of-function approaches. The initial step was provided by Hwa, a transmembrane protein that robustly activates early β-catenin signaling when microinjected into the ventral side of the embryo leading to complete twinned axes. The following step was the activation of Xenopus Nodal-related growth factors, which could rescue the depletion of β-catenin and were themselves blocked by the extracellular Nodal antagonists Cerberus-Short and Lefty. During gastrulation, the Spemann-Mangold organizer secretes a cocktail of growth factor antagonists, of which the BMP antagonists Chordin and Noggin could rescue simultaneously D-V and A-P tissues in β-catenin-depleted embryos. Surprisingly, this rescue occurred in the absence of any β-catenin transcriptional activity as measured by β-catenin activated Luciferase reporters. The Wnt antagonist Dickkopf (Dkk1) strongly synergized with the early Hwa signal by inhibiting late Wnt signals. Depletion of Sizzled (Szl), an antagonist of the Tolloid chordinase, was epistatic over the Hwa and Dkk1 synergy. BMP4 mRNA injection blocked Hwa-induced ectopic axes, and Dkk1 inhibited BMP signaling late, but not early, during gastrulation. Several unexpected findings were made, e.g., well-patterned complete embryonic axes are induced by Chordin or Nodal in β-catenin knockdown embryos, dorsalization by Lithium chloride (LiCl) is mediated by Nodals, Dkk1 exerts its anteriorizing and dorsalizing effects by regulating late BMP signaling, and the Dkk1 phenotype requires Szl.
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Affiliation(s)
- Yagmur Azbazdar
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA90095-1662
| | - Edward M. De Robertis
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA90095-1662
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2
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Evo-Devo of Urbilateria and its larval forms. Dev Biol 2022; 487:10-20. [DOI: 10.1016/j.ydbio.2022.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/28/2022] [Accepted: 04/08/2022] [Indexed: 12/14/2022]
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3
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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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4
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Kumar V, Park S, Lee U, Kim J. The Organizer and Its Signaling in Embryonic Development. J Dev Biol 2021; 9:jdb9040047. [PMID: 34842722 PMCID: PMC8628936 DOI: 10.3390/jdb9040047] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/20/2021] [Accepted: 10/29/2021] [Indexed: 12/25/2022] Open
Abstract
Germ layer specification and axis formation are crucial events in embryonic development. The Spemann organizer regulates the early developmental processes by multiple regulatory mechanisms. This review focuses on the responsive signaling in organizer formation and how the organizer orchestrates the germ layer specification in vertebrates. Accumulated evidence indicates that the organizer influences embryonic development by dual signaling. Two parallel processes, the migration of the organizer’s cells, followed by the transcriptional activation/deactivation of target genes, and the diffusion of secreting molecules, collectively direct the early development. Finally, we take an in-depth look at active signaling that originates from the organizer and involves germ layer specification and patterning.
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Affiliation(s)
- Vijay Kumar
- Department of Biochemistry, Institute of Cell Differentiation and Aging, College of Medicine, Hallym University, Chuncheon 24252, Korea;
| | - Soochul Park
- Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea;
| | - Unjoo Lee
- Department of Electrical Engineering, Hallym University, Chuncheon 24252, Korea
- Correspondence: (U.L.); (J.K.); Tel.: +82-33-248-2544 (J.K.); Fax: +82-33-244-8425 (J.K.)
| | - Jaebong Kim
- Department of Biochemistry, Institute of Cell Differentiation and Aging, College of Medicine, Hallym University, Chuncheon 24252, Korea;
- Correspondence: (U.L.); (J.K.); Tel.: +82-33-248-2544 (J.K.); Fax: +82-33-244-8425 (J.K.)
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5
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Tuazon FB, Wang X, Andrade JL, Umulis D, Mullins MC. Proteolytic Restriction of Chordin Range Underlies BMP Gradient Formation. Cell Rep 2021; 32:108039. [PMID: 32814043 PMCID: PMC7731995 DOI: 10.1016/j.celrep.2020.108039] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 04/22/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
A fundamental question in developmental biology is how morphogens, such as bone morphogenetic protein (BMP), form precise signaling gradients to impart positional and functional identity to the cells of the early embryo. We combine rigorous mutant analyses with quantitative immunofluorescence to determine that the proteases Bmp1a and Tolloid spatially restrict the BMP antagonist Chordin in dorsoventral (DV) axial patterning of the early zebrafish gastrula. We show that maternally deposited Bmp1a plays an unexpected and non-redundant role in establishing the BMP signaling gradient, while the Bmp1a/Tolloid antagonist Sizzled is surprisingly dispensable. Combining computational modeling and in vivo analyses with an immobile Chordin construct, we demonstrate that long-range Chordin diffusion is not necessary for BMP gradient formation and DV patterning. Our data do not support a counter-gradient of Chordin and instead favor a Chordin sink, established by Bmp1a and Tolloid, as the primary mechanism that drives BMP gradient formation. The BMP morphogen generates a precise signaling gradient during axial patterning. In the zebrafish embryo, Tuazon et al. find that proteases Bmp1a/Tolloid are key to this process, preventing the long-range diffusion of the BMP antagonist, Chordin. By regionally restricting Chordin, Bmp1a/Tolloid establish the signaling sink that drives BMP gradient formation.
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Affiliation(s)
- Francesca B Tuazon
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Xu Wang
- Department of Agriculture and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Jonathan Lee Andrade
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - David Umulis
- Department of Agriculture and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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6
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Cunningham CM, Bellipanni G, Habas R, Balciunas D. Deletion of morpholino binding sites (DeMOBS) to assess specificity of morphant phenotypes. Sci Rep 2020; 10:15366. [PMID: 32958829 PMCID: PMC7506532 DOI: 10.1038/s41598-020-71708-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/13/2020] [Indexed: 01/05/2023] Open
Abstract
Two complimentary approaches are widely used to study gene function in zebrafish: induction of genetic mutations, usually using targeted nucleases such as CRISPR/Cas9, and suppression of gene expression, typically using Morpholino oligomers. Neither method is perfect. Morpholinos (MOs) sometimes produce off-target or toxicity-related effects that can be mistaken for true phenotypes. Conversely, genetic mutants can be subject to compensation, or may fail to yield a null phenotype due to leakiness (e.g. use of cryptic splice sites or downstream AUGs). When discrepancy between mutant and morpholino-induced (morphant) phenotypes is observed, experimental validation of such phenotypes becomes very labor intensive. We have developed a simple genetic method to differentiate between genuine morphant phenotypes and those produced due to off-target effects. We speculated that indels within 5' untranslated regions would be unlikely to have a significant negative effect on gene expression. Mutations induced within a MO target site would result in a Morpholino-refractive allele thus suppressing true MO phenotypes whilst non-specific phenotypes would remain. We tested this hypothesis on one gene with an exclusively zygotic function, tbx5a, and one gene with strong maternal effect, ctnnb2. We found that indels within the Morpholino binding site are indeed able to suppress both zygotic and maternal morphant phenotypes. We also observed that the ability of such indels to suppress morpholino phenotypes does depend on the size and the location of the deletion. Nonetheless, mutating the morpholino binding sites in both maternal and zygotic genes can ascertain the specificity of morphant phenotypes.
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Affiliation(s)
| | - Gianfranco Bellipanni
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, 19122, USA
| | - Raymond Habas
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, 19122, USA
| | - Darius Balciunas
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, 19122, USA.
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7
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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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8
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Zhu Z, Liu Y, Xu W, Liu T, Xie Y, Sham KWY, Sha O, Cheng CHK. Functional Characterization and Expression Analyses Show Differential Roles of Maternal and Zygotic Dgcr8 in Early Embryonic Development. Front Genet 2020; 11:299. [PMID: 32296464 PMCID: PMC7136893 DOI: 10.3389/fgene.2020.00299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/13/2020] [Indexed: 12/25/2022] Open
Abstract
Dgcr8 is involved in the biogenesis of canonical miRNAs to process pri-miRNA into pre-miRNA. Previous studies have provided evidence that Dgcr8 plays an essential role in different biological processes. However, the function of maternal and zygotic Dgcr8 in early embryonic development remains largely unknown. Recently, we have reported a novel approach for generating germline-specific deletions in zebrafish. This germline knockout model offers an opportunity to investigate into the differential roles of maternal or zygotic Dgcr8. Although germline specific dgcr8 deletion has no influence on gonad development, maternal or zygotic dgcr8 is essential for embryonic development in the offspring. Both maternal dgcr8 (Mdgcr8) and maternal zygotic dgcr8 (MZdgcr8) mutants display multiple developmental defects and die within 1 week. Moreover, MZdcgr8 mutant displays more severe morphogenesis defects. However, when a miR-430 duplex (the most abundantly expressed miRNA in early embryonic stage) is used to rescue the maternal mutant phenotype, the Mdgcr8 embryos could be rescued successfully and grow into adulthood and achieve sexual maturation, whereas the MZdgcr8 embryos are only partially rescued and they all die within 1 week. The differential phenotypes between the Mdgcr8 and MZdgcr8 embryos provide us with an opportunity to study the roles of individual miRNAs during early development.
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Affiliation(s)
- Zeyao Zhu
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University, Shenzhen, China.,School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yun Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, Sun Yat-sen University, Guangzhou, China
| | - Wen Xu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Taian Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yuxin Xie
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kathy W Y Sham
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ou Sha
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University, Shenzhen, China
| | - Christopher H K Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
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9
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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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10
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Guo DD, Sun YW, Cui WT, Guo HH, Du SK, Chen J, Zou SM. Insertional mutagenesis in ChordinA induced by endogenous ΔTgf2 transposon leads to bifurcation of axial skeletal systems in grass goldfish. Sci Rep 2019; 9:4098. [PMID: 30858477 PMCID: PMC6411756 DOI: 10.1038/s41598-019-40651-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/04/2019] [Indexed: 11/19/2022] Open
Abstract
The grass goldfish appeared early in the evolutionary history of goldfish, and shows heritable stability in the development of the caudal fin. The twin-tail phenotype is extremely rare, however, some twin-tail individuals were produced in the process of breeding for ornamental value. From mutations in the twin-tail goldfish genome, we identified two kinds of Tgf2 transposons. One type was completely sequenced Tgf2 and the other type was ΔTgf2, which had 858 bp missing. We speculate that the bifurcation of the axial skeletal system in goldfish may be caused by an endogenous ΔTgf2 insertion mutation in Chordin A, as ΔTgf2 has no transposition activity and blocks the expression of Chordin A. The twin-tail showed doubled caudal fin and accumulation of red blood cells in the tail. In addition, in situ hybridization revealed that ventral embryonic tissue markers (eve1, sizzled, and bmp4) were more widely and strongly expressed in the twin-tail than in the wild-type embryos during the gastrula stage, and bmp4 showed bifurcated expression patterns in the posterior region of the twin-tail embryos. These results provide new insights into the artificial breeding of genetically stable twin-tail grass goldfish families.
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Affiliation(s)
- Dan-Dan Guo
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Yi-Wen Sun
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Wen-Tao Cui
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Hong-Hong Guo
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Shang-Ke Du
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Jie Chen
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China
| | - Shu-Ming Zou
- Genetics and Breeding Center for Blunt Snout Bream, Ministry of Agriculture, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China.
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11
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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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12
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Mucha BE, Hashiguchi M, Zinski J, Shore EM, Mullins MC. Variant BMP receptor mutations causing fibrodysplasia ossificans progressiva (FOP) in humans show BMP ligand-independent receptor activation in zebrafish. Bone 2018; 109:225-231. [PMID: 29307777 PMCID: PMC5866198 DOI: 10.1016/j.bone.2018.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/23/2017] [Accepted: 01/03/2018] [Indexed: 11/28/2022]
Abstract
The large majority of cases of the autosomal dominant human disease fibrodysplasia ossificans progressiva (FOP) are caused by gain-of-function Arg206His mutations in the BMP type I receptor ACVR1 (ALK2). The Arg206His mutation is located in the GS domain of the type I receptor. This region is normally phosphorylated by the BMP type II receptor, which activates the type I receptor to phosphorylate its substrate, the signal transducer Smad1/5/8. A small subset of patients with FOP carry variant mutations in ACVR1 altering Gly328 to Trp, Glu or Arg. Since these mutations lie outside the GS domain, the mechanism through which ACVR1 Gly328 mutations cause disease remains unclear. We used a zebrafish embryonic development assay to test the signaling of human ACVR1 Gly328 mutant receptors comparing them to the Arg206His mutant. In this assay increased or decreased BMP pathway activation alters dorsal-ventral axial patterning, providing a sensitive assay for altered BMP signaling levels. We expressed the human ACVR1 Gly328 mutant receptors in zebrafish embryos to investigate their signaling activities. We found that all ACVR1 Gly328 human mutations ventralized wild-type embryos and could partially rescue Bmp7-deficient embryos, indicating that these mutant receptors can activate BMP signaling in a BMP ligand-independent manner. The degree of ventralization or rescue was similar among all three Gly328 mutants. Smad1/5 phosphorylation, a readout of BMP receptor signaling, was mildly increased by ACVR1 Gly328 mutations. Gene expression analyses demonstrate expanded ventral and reciprocal loss of dorsal cell fate markers. This study demonstrates that Gly328 mutants increase receptor activation and BMP ligand-independent signaling through Smad phosphorylation.
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Affiliation(s)
- Bettina E Mucha
- Division of Human Genetics and Molecular Biology, and Division of Biochemical Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Pediatrics, Universite de Montreal, Montreal, QC, Canada
| | - Megumi Hashiguchi
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph Zinski
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Eileen M Shore
- Department of Orthopedic Surgery, and the Center for Research in FOP and Related Disorders, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, and the Center for Research in FOP and Related Disorders, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
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13
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Zinski J, Bu Y, Wang X, Dou W, Umulis D, Mullins MC. Systems biology derived source-sink mechanism of BMP gradient formation. eLife 2017; 6:22199. [PMID: 28826472 PMCID: PMC5590806 DOI: 10.7554/elife.22199] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 08/08/2017] [Indexed: 02/06/2023] Open
Abstract
A morphogen gradient of Bone Morphogenetic Protein (BMP) signaling patterns the dorsoventral embryonic axis of vertebrates and invertebrates. The prevailing view in vertebrates for BMP gradient formation is through a counter-gradient of BMP antagonists, often along with ligand shuttling to generate peak signaling levels. To delineate the mechanism in zebrafish, we precisely quantified the BMP activity gradient in wild-type and mutant embryos and combined these data with a mathematical model-based computational screen to test hypotheses for gradient formation. Our analysis ruled out a BMP shuttling mechanism and a bmp transcriptionally-informed gradient mechanism. Surprisingly, rather than supporting a counter-gradient mechanism, our analyses support a fourth model, a source-sink mechanism, which relies on a restricted BMP antagonist distribution acting as a sink that drives BMP flux dorsally and gradient formation. We measured Bmp2 diffusion and found that it supports the source-sink model, suggesting a new mechanism to shape BMP gradients during development. Before an animal is born, a protein called BMP plays a key role in establishing the difference between the front and the back of the animal. Cells nearer the front of the embryo contain higher amounts of the BMP protein, whilst cells nearer the back have progressively lower levels of BMP. This gradient of BMP ‘concentration’ affects the identity of the cells, with the level of BMP in each cell dictating what parts of the body are made where. The prevailing view among scientists is that the BMP gradient is created by an opposing gradient of another protein called Chordin, which is found at high levels at the back of the embryo and lower levels near the front. Chordin inhibits BMP and the interaction between the two proteins establishes the gradients that create order across the embryo. Zinski et al. used computer models to investigate how the BMP gradient is created. Several possibilities were considered, including the effect of Chordin. Comparing the models to precise experimental measurements of BMP activity in zebrafish embryos suggested that a different mechanism known as a source-sink model, rather than the opposing Chordin gradient, may be responsible for the pattern of BMP found in the embryo. In this model, the BMP is produced at the front of the embryo and moves towards the back end by diffusion. At the back of the embryo, BMP is mopped up by Chordin, resulting in a constant gradient of BMP along the embryo. Many other processes that control how animals grow and develop rely on the formation of similar protein gradients, so these findings may also apply to other aspects of animal development. Understanding how animals grow and develop may help researchers to develop strategies to regrow tissues and organs in human patients.
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Affiliation(s)
- Joseph Zinski
- Department of Cell and DevelopmentalBiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
| | - Ye Bu
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, United States
| | - Xu Wang
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, United States
| | - Wei Dou
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, United States
| | - David Umulis
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, United States
| | - Mary C Mullins
- Department of Cell and DevelopmentalBiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
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14
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Abstract
The discovery of the transforming growth factor β (TGF-β) family ligands and the realization that their bioactivities need to be tightly controlled temporally and spatially led to intensive research that has identified a multitude of extracellular modulators of TGF-β family ligands, uncovered their functions in developmental and pathophysiological processes, defined the mechanisms of their activities, and explored potential modulator-based therapeutic applications in treating human diseases. These studies revealed a diverse repertoire of extracellular and membrane-associated molecules that are capable of modulating TGF-β family signals via control of ligand availability, processing, ligand-receptor interaction, and receptor activation. These molecules include not only soluble ligand-binding proteins that were conventionally considered as agonists and antagonists of TGF-β family of growth factors, but also extracellular matrix (ECM) proteins and proteoglycans that can serve as "sink" and control storage and release of both the TGF-β family ligands and their regulators. This extensive network of soluble and ECM modulators helps to ensure dynamic and cell-specific control of TGF-β family signals. This article reviews our knowledge of extracellular modulation of TGF-β growth factors by diverse proteins and their molecular mechanisms to regulate TGF-β family signaling.
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Affiliation(s)
- Chenbei Chang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294
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15
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Dosch R. Next generation mothers: Maternal control of germline development in zebrafish. Crit Rev Biochem Mol Biol 2014; 50:54-68. [DOI: 10.3109/10409238.2014.985816] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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16
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Abe G, Lee SH, Chang M, Liu SC, Tsai HY, Ota KG. The origin of the bifurcated axial skeletal system in the twin-tail goldfish. Nat Commun 2014; 5:3360. [PMID: 24569511 PMCID: PMC3948052 DOI: 10.1038/ncomms4360] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/31/2014] [Indexed: 11/09/2022] Open
Abstract
Twin-tail goldfish possess a bifurcated caudal axial skeleton. The scarcity of this trait in nature suggests that a rare mutation, which drastically altered the mechanisms underlying axial skeleton formation, may have occurred during goldfish domestication. However, little is known about the molecular development of twin-tail goldfish. Here we show that the bifurcated caudal skeleton arises from a mutation in the chordin gene, which affects embryonic dorsal–ventral (DV) patterning. We demonstrate that formation of the bifurcated caudal axial skeleton requires a stop-codon mutation in one of two recently duplicated chordin genes; this mutation may have occurred within approximately 600 years of domestication. We also report that the ventral tissues of the twin-tail strain are enlarged, and form the embryonic bifurcated fin fold. However, unlike previously described chordin-deficient embryos, this is not accompanied by a reduction in anterior–dorsal neural tissues. These results provide insight into large-scale evolution arising from artificial selection. The ornamental twin-tail goldfish has a bifurcated caudal skeleton that arose during domestication, but the developmental mechanisms that generate this tail are unknown. Here, Abe et al. show that a mutation in the chordin gene affects embryonic dorsal–ventral patterning causing the bifurcated tail skeleton.
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Affiliation(s)
- Gembu Abe
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
| | - Shu-Hua Lee
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
| | - Mariann Chang
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
| | - Shih-Chieh Liu
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
| | - Hsin-Yuan Tsai
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
| | - Kinya G Ota
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan 26242, Taiwan
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O'Neill K, Thorpe C. BMP signaling and spadetail regulate exit of muscle precursors from the zebrafish tailbud. Dev Biol 2013; 375:117-27. [PMID: 23246591 DOI: 10.1016/j.ydbio.2012.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 11/26/2012] [Accepted: 12/04/2012] [Indexed: 11/19/2022]
Abstract
The tailbud is a population of stem cells in the posterior embryonic tail. During zebrafish development, these stem cells give rise to the main structures of the embryo's posterior body, including the tail somites. Progenitor cells reside in the tailbud for variable amounts of time before they exit and begin to differentiate. There must be a careful balance between cells that leave the tailbud and cells that are held back in order to give rise to later somites. However, this meticulous process is not well understood. A gene that has shed some light on this area is the t-box transcription factor spadetail (spt). When spt is mutated, embryos develop an enlarged tailbud and are only able to form roughly half of their somites. This phenotype is due to the fact that some of the somitic precursors are not able to leave the tailbud or differentiate. Another factor involved in tail morphogenesis is the Bone Morphogenetic Protein (BMP) pathway. BMPs are important for many processes during early development, including cell migration. Chordino (chd) is a secreted protein that inhibits BMP signaling. BMPs are upregulated in chd mutants, however, these mutants are able to form organized somites. In embryos where chd and spt are mutated, somites are completely absent. These double mutants also develop a large tailbud due to the accumulation of progenitor cells that are never able to leave or differentiate. To study the dynamics of cells in the tailbud and their role in somite formation, we have analyzed the genetic factors and pathway interactions involved, conducted transplant experiments to look at behavior of mutant cells in different genetic backgrounds, and used time lapse microscopy to characterize cell movements and behavior in wild type and mutant tailbuds. These data suggest that spt expression and BMP inhibition are both required for somitic precursors to exit the tailbud. They also elucidate that chd;spt tailbud mesodermal progenitor cells (MPC) behave autonomously and their dynamics within the tailbud are drastically different than WT MPCs.
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Affiliation(s)
- Katelyn O'Neill
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA.
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18
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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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19
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Gui W, Dong Q, Zhou S, Wang X, Liu S, Zhu G. Waterborne exposure to clodinafop-propargyl disrupts the posterior and ventral development of zebrafish embryos. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:1576-1581. [PMID: 21495064 DOI: 10.1002/etc.549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Revised: 09/06/2010] [Accepted: 12/05/2010] [Indexed: 05/30/2023]
Abstract
Clodinafop-propargyl, an aryloxyphenoxypropionate herbicide, is widely used for the control of annual grasses. However, research focusing on the ecotoxicity of this herbicide is limited. The present study employed zebrafish (Danio rerio) as a model to investigate its developmental toxicity. Embryos were exposed to a range of concentrations from 0.2 µM to 5 µM starting at late cleavage stage (2 h postfertilization, [hpf]) or late gastrulation stage (10 hpf). The results showed that the two exposure strategies had the same minimum teratogenic concentration of 0.6 µM but caused different groups of morphogenetic malformations. When exposure was initiated at 2 hpf, clodinafop-propargyl caused various embryonic phenotypes, including embryos with a fin gap in the ventral tail and embryos with coiled tail. When exposure was initiated at 10 hpf, clodinafop-propargyl resulted in failure of the tail to detach, in which the ventral tissues failed to grow out but instead adhered to the yolk extension, and the defect differed to various degrees among embryos. Similar effects were observed for embryos exposed to clodinafop, the metabolite of clodinafop-propargyl. Because these defects were mainly confined to the posterior and ventral region that derived from ventral blastoderm cells, we have evaluated the expression of the ventral mesoderm marker gene gata-1 and ventral ectoderm marker gene gata-3. No significant alteration was seen in gata-1 expression except for the expanded blood islands, whereas the expression of gata-3 was significantly reduced. Our findings showed that clodinafop-propargyl exposure disturbed embryonic patterning and fate specification of ventrally derived gastrula ectoderm cells.
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Affiliation(s)
- Wenjun Gui
- Zhejiang University, Hangzhou, Zhejiang, Peoples Republic of China
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20
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Li D, Sun H, Deng W, Tao D, Liu Y, Ma Y. Zili Antagonizes Bmp Signaling to Regulate Dorsal-Ventral Patterning during Zebrafish Early Embryogenesis. Zoolog Sci 2011; 28:397-402. [DOI: 10.2108/zsj.28.397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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21
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Wise SB, Stock DW. bmp2b and bmp4 are dispensable for zebrafish tooth development. Dev Dyn 2011; 239:2534-46. [PMID: 21038444 DOI: 10.1002/dvdy.22411] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Bone morphogenetic protein (Bmp) signaling has been shown to play important roles in tooth development at virtually all stages from initiation to hard tissue formation. The specific ligands involved in these processes have not been directly tested by loss-of-function experiments, however. We used morpholino antisense oligonucleotides and mutant analysis in the zebrafish to reduce or eliminate the function of bmp2b and bmp4, two ligands known to be expressed in zebrafish teeth and whose mammalian orthologs are thought to play important roles in tooth development. Surprisingly, we found that elimination of function of these two genes singly and in combination did not prevent the formation of mature, attached teeth. The mostly likely explanation for this result is functional redundancy with other Bmp ligands, which may differ between the zebrafish and the mouse.
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Affiliation(s)
- Sarah B Wise
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309-0449, USA
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22
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Rogers C, Moody SA, Casey E. Neural induction and factors that stabilize a neural fate. BIRTH DEFECTS RESEARCH. PART C, EMBRYO TODAY : REVIEWS 2009; 87:249-62. [PMID: 19750523 PMCID: PMC2756055 DOI: 10.1002/bdrc.20157] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The neural ectoderm of vertebrates forms when the bone morphogenetic protein (BMP) signaling pathway is suppressed. Herein, we review the molecules that directly antagonize extracellular BMP and the signaling pathways that further contribute to reduce BMP activity in the neural ectoderm. Downstream of neural induction, a large number of "neural fate stabilizing" (NFS) transcription factors are expressed in the presumptive neural ectoderm, developing neural tube and ultimately in neural stem cells. Herein, we review what is known about their activities during normal development to maintain a neural fate and regulate neural differentiation. Further elucidation of how the NFS genes interact to regulate neural specification and differentiation should ultimately prove useful for regulating the expansion and differentiation of neural stem and progenitor cells.
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Affiliation(s)
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, The George Washington University
| | - Elena Casey
- Department of Biology, Georgetown University
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23
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Chan TM, Longabaugh W, Bolouri H, Chen HL, Tseng WF, Chao CH, Jang TH, Lin YI, Hung SC, Wang HD, Yuh CH. Developmental gene regulatory networks in the zebrafish embryo. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1789:279-98. [PMID: 18992377 DOI: 10.1016/j.bbagrm.2008.09.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 08/21/2008] [Accepted: 09/22/2008] [Indexed: 01/12/2023]
Abstract
The genomic developmental program operates mainly through the regulated expression of genes encoding transcription factors and signaling pathways. Complex networks of regulatory genetic interactions control developmental cell specification and fates. Development in the zebrafish, Danio rerio, has been studied extensively and large amounts of experimental data, including information on spatial and temporal gene expression patterns, are available. A wide variety of maternal and zygotic regulatory factors and signaling pathways have been discovered in zebrafish, and these provide a useful starting point for reconstructing the gene regulatory networks (GRNs) underlying development. In this review, we describe in detail the genetic regulatory subcircuits responsible for dorsoanterior-ventroposterior patterning and endoderm formation. We describe a number of regulatory motifs, which appear to act as the functional building blocks of the GRNs. Different positive feedback loops drive the ventral and dorsal specification processes. Mutual exclusivity in dorsal-ventral polarity in zebrafish is governed by intra-cellular cross-inhibiting GRN motifs, including vent/dharma and tll1/chordin. The dorsal-ventral axis seems to be determined by competition between two maternally driven positive-feedback loops (one operating on Dharma, the other on Bmp). This is the first systematic approach aimed at developing an integrated model of the GRNs underlying zebrafish development. Comparison of GRNs' organizational motifs between different species will provide insights into developmental specification and its evolution. The online version of the zebrafish GRNs can be found at http://www.zebrafishGRNs.org.
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Affiliation(s)
- Tzu-Min Chan
- Division of Molecular and Genomic Medicine, National Health Research Institute, Taiwan, Republic of China
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24
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Mudumana SP, Hentschel D, Liu Y, Vasilyev A, Drummond IA. odd skipped related1 reveals a novel role for endoderm in regulating kidney versus vascular cell fate. Development 2008; 135:3355-67. [PMID: 18787069 DOI: 10.1242/dev.022830] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The kidney and vasculature are intimately linked both functionally and during development, when nephric and blood/vascular progenitor cells occupy adjacent bands of mesoderm in zebrafish and frog embryos. Developmental mechanisms that underlie the differentiation of kidney versus blood/vascular lineages remain unknown. The odd skipped related1 (osr1) gene encodes a zinc-finger transcription factor that is expressed in the germ ring mesendoderm and subsequently in the endoderm and intermediate mesoderm, prior to the expression of definitive kidney or blood/vascular markers. Knockdown of osr1 in zebrafish embryos resulted in a complete, segment-specific loss of anterior kidney progenitors and a compensatory increase in the number of angioblast cells in the same trunk region. Histology revealed a subsequent absence of kidney tubules, an enlarged cardinal vein and expansion of the posterior venous plexus. Altered kidney versus vascular development correlated with expanded endoderm development in osr1 knockdowns. Combined osr1 loss of function and blockade of endoderm development by knockdown of sox32/casanova rescued anterior kidney development. The results indicate that osr1 activity is required to limit endoderm differentiation from mesendoderm; in the absence of osr1, excess endoderm alters mesoderm differentiation, shifting the balance from kidney towards vascular development.
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Affiliation(s)
- Sudha P Mudumana
- Nephrology Division, Massachusetts General Hospital, Charlestown, MA 02129, USA
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25
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Wittler L, Saborowski M, Kessel M. Expression of the chick Sizzled gene in progenitors of the cardiac outflow tract. Gene Expr Patterns 2008; 8:471-476. [DOI: 10.1016/j.gep.2008.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 02/20/2008] [Accepted: 02/22/2008] [Indexed: 12/19/2022]
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26
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A PATO-compliant zebrafish screening database (MODB): management of morpholino knockdown screen information. BMC Bioinformatics 2008; 9:7. [PMID: 18179718 PMCID: PMC2221974 DOI: 10.1186/1471-2105-9-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2007] [Accepted: 01/07/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The zebrafish is a powerful model vertebrate amenable to high throughput in vivo genetic analyses. Examples include reverse genetic screens using morpholino knockdown, expression-based screening using enhancer trapping and forward genetic screening using transposon insertional mutagenesis. We have created a database to facilitate web-based distribution of data from such genetic studies. DESCRIPTION The MOrpholino DataBase is a MySQL relational database with an online, PHP interface. Multiple quality control levels allow differential access to data in raw and finished formats. MODBv1 includes sequence information relating to almost 800 morpholinos and their targets and phenotypic data regarding the dose effect of each morpholino (mortality, toxicity and defects). To improve the searchability of this database, we have incorporated a fixed-vocabulary defect ontology that allows for the organization of morpholino affects based on anatomical structure affected and defect produced. This also allows comparison between species utilizing Phenotypic Attribute Trait Ontology (PATO) designated terminology. MODB is also cross-linked with ZFIN, allowing full searches between the two databases. MODB offers users the ability to retrieve morpholino data by sequence of morpholino or target, name of target, anatomical structure affected and defect produced. CONCLUSION MODB data can be used for functional genomic analysis of morpholino design to maximize efficacy and minimize toxicity. MODB also serves as a template for future sequence-based functional genetic screen databases, and it is currently being used as a model for the creation of a mutagenic insertional transposon database.
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Hagos EG, Fan X, Dougan ST. The role of maternal Activin-like signals in zebrafish embryos. Dev Biol 2007; 309:245-58. [PMID: 17692308 DOI: 10.1016/j.ydbio.2007.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Revised: 06/24/2007] [Accepted: 07/12/2007] [Indexed: 12/15/2022]
Abstract
Maternal Activin-like proteins, a subgroup of the TGF-beta superfamily, play a key role in establishing the body axes in many vertebrates, but their role in teleosts is unclear. At least two maternal Activin-like proteins are expressed in zebrafish, including the Vg1 orthologue, zDVR-1, and the nodal-related gene, Squint. Our analysis of embryos lacking both maternal and zygotic squint function revealed that maternal squint is required in some genetic backgrounds for the formation of dorsal and anterior tissues. Conditional inactivation of the ALK4, 5 and 7 receptors by SB-505124 treatment during the cleavage stages ruled out a role for maternal Squint, zDVR-1, or other Activin-like ligands before the mid-blastula transition, when the dorsal axis is established. Furthermore, we show that maternal Squint and zDVR-1 are not required during the cleavage stages to induce zygotic nodal-related gene expression. nodal-related gene expression decreases when receptor inhibition continues past the mid-blastula transition, resulting in a progressive loss of mesoderm and endoderm. We conclude that maternally expressed Activin-like signals do not act before the mid-blastula transition in zebrafish, but do have a variably penetrant role in the later stages of axis formation. This contrasts with the early role for these signals during Xenopus development.
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Affiliation(s)
- Engda G Hagos
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA
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Abstract
Bone morphogenetic proteins (BMPs) are known to be widely involved in various biological processes. Many of the members of the BMP family, as well as related factors, receptors and molecules in the BMP signaling pathway, have been isolated, but their precise functions are still unclear. In addition to the 'classical' model organism Xenopus, zebrafish, Danio rerio, is now considered to be a suitable model organism to study the roles of the BMP signaling pathway during embryogenesis. Mutagenesis screens have identified a number of mutants in the pathway. Although they do not cover the entire members of the BMP signaling cascade that are currently known, they serve as a powerful tool to broaden our understanding of BMP functions, in combination with other experimental techniques.
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Affiliation(s)
- Mariko Kondo
- Department of Biological Sciences, The University of Tokyo, Japan.
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29
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Dal-Pra S, Fürthauer M, Van-Celst J, Thisse B, Thisse C. Noggin1 and Follistatin-like2 function redundantly to Chordin to antagonize BMP activity. Dev Biol 2006; 298:514-26. [PMID: 16890217 DOI: 10.1016/j.ydbio.2006.07.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Revised: 07/06/2006] [Accepted: 07/07/2006] [Indexed: 11/28/2022]
Abstract
In Xenopus, the dorso-ventral (D/V) axis is thought to be specified by the bone morphogenetic proteins (Bmp) activity arising through interaction with antagonists such as Noggin, Chordin and Follistatin. We report here, through inactivation of noggin1 (nog1) that this gene is not essential by itself to establish the D/V patterning. However, at blastula stage, inactivation of nog1 strongly amplifies chordin (chd) phenotype, revealing redundant functions of these two genes on D/V axis formation. Substantial dorsal tissues remaining in the double nog1-chd morphant suggested that other anti-Bmp factors may pattern the D/V axis. We isolated two potential candidates, the follistatin-like (fstl) genes. We found that fstl2 is an early gastrula expressed gene. Its inactivation, similar to nog1, strongly enhances the chd phenotype. Moreover, the penetrance of the ventralization phenotype is much higher when we inactivated simultaneously chd, nog1 and fstl2. Altogether, our data reveal that, while Chordin is the main player of the D/V axis, sufficient to maintain proper activity of Bmp gradient, the structures remaining in the chd mutant (namely dorsal and dorso-lateral territories, in both mesodermal and ectodermal layers) result from the anti-Bmp activity carried by Nog1 and Fstl2 at blastula and gastrula stages.
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Affiliation(s)
- Sophie Dal-Pra
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/INSERM/ULP, 1 rue Laurent Fries, BP 10142, CU de Strasbourg, 67404 ILLKIRCH Cedex, France
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31
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Abstract
The enigma of Sizzled, a secreted Frizzled-related protein, has been resolved in a recent study from the De Robertis lab ( [in the January 13 issue of Cell]). Sizzled, although homologous to other Wnt antagonists, does not function as such, nor does it function within a Wnt signaling pathway. Remarkably it functions as an antagonist of BMP signaling, competing with Chordin for binding to its inhibitor a Tolloid-related metalloprotease. This competition protects Chordin from cleavage, thus allowing it to bind and limit BMP signaling.
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Affiliation(s)
- Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Abstract
The basic vertebrate body plan of the zebrafish embryo is established in the first 10 hours of development. This period is characterized by the formation of the anterior-posterior and dorsal-ventral axes, the development of the three germ layers, the specification of organ progenitors, and the complex morphogenetic movements of cells. During the past 10 years a combination of genetic, embryological, and molecular analyses has provided detailed insights into the mechanisms underlying this process. Maternal determinants control the expression of transcription factors and the location of signaling centers that pattern the blastula and gastrula. Bmp, Nodal, FGF, canonical Wnt, and retinoic acid signals generate positional information that leads to the restricted expression of transcription factors that control cell type specification. Noncanonical Wnt signaling is required for the morphogenetic movements during gastrulation. We review how the coordinated interplay of these molecules determines the fate and movement of embryonic cells.
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Affiliation(s)
- Alexander F Schier
- Developmental Genetics Program, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, NY 10016-6497, USA.
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33
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Lee HX, Ambrosio AL, Reversade B, De Robertis E. Embryonic dorsal-ventral signaling: secreted frizzled-related proteins as inhibitors of tolloid proteinases. Cell 2006; 124:147-59. [PMID: 16413488 PMCID: PMC2486255 DOI: 10.1016/j.cell.2005.12.018] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 11/23/2005] [Accepted: 12/13/2005] [Indexed: 11/26/2022]
Abstract
Here we report an unexpected role for the secreted Frizzled-related protein (sFRP) Sizzled/Ogon as an inhibitor of the extracellular proteolytic reaction that controls BMP signaling during Xenopus gastrulation. Microinjection experiments suggest that the Frizzled domain of Sizzled regulates the activity of Xolloid-related (Xlr), a metalloproteinase that degrades Chordin, through the following molecular pathway: Szl -| Xlr -| Chd -| BMP --> P-Smad1 --> Szl. In biochemical assays, the Xlr proteinase has similar affinities for its endogenous substrate Chordin and for its competitive inhibitor Sizzled, which is resistant to enzyme digestion. Extracellular levels of Sizzled and Chordin in the gastrula embryo and enzyme reaction constants were all in the 10(-8) M range, consistent with a physiological role in the regulation of dorsal-ventral patterning. Sizzled is also a natural inhibitor of BMP1, a Tolloid metalloproteinase of medical interest. Furthermore, mouse sFRP2 inhibited Xlr, suggesting a wider role for this molecular mechanism.
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Affiliation(s)
- Hojoon X. Lee
- Howard Hughes Medical Institute and Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - Andrea L. Ambrosio
- Howard Hughes Medical Institute and Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - Bruno Reversade
- Howard Hughes Medical Institute and Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - E.M. De Robertis
- Howard Hughes Medical Institute and Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
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Little SC, Mullins MC. Extracellular modulation of BMP activity in patterning the dorsoventral axis. ACTA ACUST UNITED AC 2006; 78:224-42. [PMID: 17061292 DOI: 10.1002/bdrc.20079] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Signaling via bone morphogenetic proteins (BMPs) regulates a vast array of diverse biological processes in the developing embryo and in postembryonic life. Many insights into BMP signaling derive from studies of the BMP signaling gradients that pattern cell fates along the embryonic dorsal-ventral (DV) axis of both vertebrates and invertebrates. This review examines recent developments in the field of DV patterning by BMP signaling, focusing on extracellular modulation as a key mechanism in the formation of BMP signaling gradients in Drosophila, Xenopus, and zebrafish.
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Affiliation(s)
- Shawn C Little
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6058, USA
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35
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Ghiselli G, Farber SA. D-glucuronyl C5-epimerase acts in dorso-ventral axis formation in zebrafish. BMC DEVELOPMENTAL BIOLOGY 2005; 5:19. [PMID: 16156897 PMCID: PMC1250224 DOI: 10.1186/1471-213x-5-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 09/12/2005] [Indexed: 11/10/2022]
Abstract
BACKGROUND Heparan sulfate (HS) is an ubiquitous component of the extracellular matrix that binds and modulates the activity of growth factors, cytokines and proteases. Animals with defective HS biosynthesis display major developmental abnormalities however the processes that are affected remain to be defined. D-glucuronyl-C5-epimerase (Glce) is a key HS chain modifying enzyme that catalyses the conversion of glucuronic acid into iduronic acid, a biosynthetic step that enhances HS biological activity. In this study the role of Glce during early zebrafish development has been investigated. RESULTS Two Glce-like proteins (Glce-A and -B) are expressed in zebrafish at all times. They are the products of two distinct genes that, based on chromosomal mapping, are both orthologues of the same single human gene. Transcripts for both proteins were detected in fertilized zebrafish embryos prior to the onset of zygotic transcription indicating their maternal origin. At later developmental stages the epimerases are expressed widely throughout gastrulation and then become restricted to the hindbrain at 24 h post-fertilization. By monitoring the expression of well characterized marker genes during gastrulation, we have found that misexpression of Glce causes a dose-dependent expansion of the ventral structures, whereas protein knockdown using targeted antisense morpholino oligonucleotides promotes axis dorsalization. The ventralizing activity of Bmp2b is enhanced by Glce overexpression whereas Glce knockdown impairs Bmp2b activity. CONCLUSION Glce activity is an important determinant of of dorso-ventral axis formation and patterning in zebrafish. In particular Glce acts during gastrulation by affecting Bmp-mediated cell specification. The results obtained further corroborate the concept that HS encodes information that affect morphogenesis during early vertebrate development.
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Affiliation(s)
- Giancarlo Ghiselli
- Department of Pathology and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
- Kimmel Cancer Center, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Steven A Farber
- Kimmel Cancer Center, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
- Department of Microbiology and Immunology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
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diIorio PJ, Runko A, Farrell CA, Roy N. Sid4: A secreted vertebrate immunoglobulin protein with roles in zebrafish embryogenesis. Dev Biol 2005; 282:55-69. [PMID: 15936329 DOI: 10.1016/j.ydbio.2005.02.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2004] [Revised: 02/22/2005] [Accepted: 02/23/2005] [Indexed: 10/25/2022]
Abstract
The small members of the immunoglobulin superfamily (IGSF) are a molecularly diverse group of proteins composed solely of immunoglobulin domains. They may be secreted or tethered to the cell mebrane via GPI linkages and are proposed to have important functions in vivo. However, very few small IGSFs have been functionally characterized. During an ongoing in situ hybridization analysis of expressed sequence tags in zebrafish we identified secreted immunoglobulin domain 4 (sid4), a gene encoding a soluble vertebrate protein composed solely of four immunoglobulin domains. Throughout development, sid4 is expressed in regions of the embryo undergoing active cell division and migration. Functional analysis using morpholino antisense oligonucleotides demonstrates that timing of gene expression is normal in morphants, but these embryos are smaller and exhibit defects in epiboly and patterning of axial and prechordal mesoderm. Analyses of chordin, pax2, krox20, and dlx2 expression in morphants demonstrate that early brain patterning is normal but later organization of hindbrain neurons and development of cranial neural crest are perturbed. Levels of apoptosis in morphants were normal prior to 90% epiboly, but were elevated after 10 h post-fertilization (hpf). Apoptosis does not account for early patterning defects of axial mesoderm, but likely contributes to overall reduction in embryo size. Phylogenetic analysis demonstrates that Sid4 is strikingly similar to the fibronectin binding Ig domains of Perlecan/HSPG2. Overall, our data demonstrate a fundamental role for sid4, possibly as a co-factor in extracellular matrix (ECM) interactions, in processes underlying tissue patterning and organogenesis in a vertebrate.
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Affiliation(s)
- P J diIorio
- Division of Diabetes, University of Massachusetts Medical School, 373 Plantation Street, Suite 218, Worcester, MA 01605, USA.
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37
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Little SC, Mullins MC. Twisted gastrulation promotes BMP signaling in zebrafish dorsal-ventral axial patterning. Development 2004; 131:5825-35. [PMID: 15525664 DOI: 10.1242/dev.01464] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In vertebrates and invertebrates, the bone morphogenetic protein (BMP) signaling pathway patterns cell fates along the dorsoventral (DV) axis. In vertebrates, BMP signaling specifies ventral cell fates, whereas restriction of BMP signaling by extracellular antagonists allows specification of dorsal fates. In misexpression assays, the conserved extracellular factor Twisted gastrulation (Tsg) is reported to both promote and antagonize BMP signaling in DV patterning. To investigate the role of endogenous Tsg in early DV patterning, we performed morpholino (MO)-based knockdown studies of Tsg1 in zebrafish. We found that loss of tsg1 results in a moderately strong dorsalization of the embryonic axis, suggesting that Tsg1 promotes ventral fates. Knockdown of tsg1 combined with loss of function of the BMP agonist tolloid (mini fin) or heterozygosity for the ligand bmp2b (swirl) enhanced dorsalization, supporting a role for Tsg1 in specifying ventral cell fates as a BMP signaling agonist. Moreover, loss of tsg1 partially suppressed the ventralized phenotypes of mutants of the BMP antagonists Chordin or Sizzled (Ogon). Our results support a model in which zebrafish Tsg1 promotes BMP signaling, and thus ventral cell fates, during DV axial patterning.
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Affiliation(s)
- Shawn C Little
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, 1211 BRBII/III, 421 Curie Boulevard, Philadelphia, PA 19104-6058, USA
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38
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Yamamoto Y, Oelgeschläger M. Regulation of bone morphogenetic proteins in early embryonic development. Naturwissenschaften 2004; 91:519-34. [PMID: 15517134 DOI: 10.1007/s00114-004-0575-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bone morphogenetic proteins (BMPs), a large subgroup of the TGF-beta family of secreted growth factors, control fundamental events in early embryonic development, organogenesis and adult tissue homeostasis. The plethora of dose-dependent cellular processes regulated by BMP signalling demand a tight regulation of BMP activity. Over the last decade, a number of proteins have been identified that bind BMPs in the extracellular space and regulate the interaction of BMPs with their cognate receptors, including the secreted BMP antagonist Chordin. In the early vertebrate embryo, the localized secretion of BMP antagonists from the dorsal blastopore lip establishes a functional BMP signalling gradient that is required for the determination of the dorsoventral - or back to belly - body axis. In particular, inhibition of BMP activity is essential for the formation of neural tissue in the development of vertebrate and invertebrate embryos. Here we review recent studies that have provided new insight into the regulation of BMP signalling in the extracellular space. In particular, we discuss the recently identified Twisted gastrulation protein that modulates, in concert with metalloproteinases of the Tolloid family, the interaction of Chordin with BMP and a family of proteins that share structural similarities with Chordin in the respective BMP binding domains. In addition, genetic and functional studies in zebrafish and frog provide compelling evidence that the secreted protein Sizzled functionally interacts with the Chd-BMP pathway, despite being expressed ventrally in the early gastrula-stage embryo. These intriguing discoveries may have important implications, not only for our current concept of early embryonic patterning, but also for the regulation of BMP activity at later developmental stages and tissue homeostasis in the adult.
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Affiliation(s)
- Yukiyo Yamamoto
- Department of Developmental Biology, Max-Planck Institute of Immunobiology, Stübeweg 51, 79108, Freiburg, Germany
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39
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Pelegri F, Dekens MPS, Schulte-Merker S, Maischein HM, Weiler C, Nüsslein-Volhard C. Identification of recessive maternal-effect mutations in the zebrafish using a gynogenesis-based method. Dev Dyn 2004; 231:324-35. [PMID: 15366009 DOI: 10.1002/dvdy.20145] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In animal species, early developmental processes are driven by maternally derived factors. Here, we describe a forward genetics approach to identify recessive mutations in genes encoding such maternal factors in the zebrafish. We used a gynogenesis-based approach to identify 14 recessive maternal-effect mutations. Homozygosity for these mutations in adult females leads to the inviability of their offspring. Confocal microscopy of embryos labeled with a DNA dye and a membrane marker allowed us to further analyze mutant embryos for defects in nuclear and cellular divisions. The mutations result in a range of defects in early developmental processes, including egg activation, early nuclear events, mitosis, cytokinesis, axial patterning, and gastrulation. Our effort constitutes a systematic attempt to identify maternal-effect genes in a vertebrate species. The sample of mutations that we have identified reflects the diversity of maternally driven functions in early development and underscores the importance of maternal factors in this process.
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Affiliation(s)
- Francisco Pelegri
- Max-Plank Institut für Entwicklungsbiologie, Abteilung Genetik, Tübingen, Germany.
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40
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Abstract
All processes that occur before the activation of the zygotic genome at the midblastula transition are driven by maternal products, which are produced during oogenesis and stored in the mature oocyte. Upon egg activation and fertilization, these maternal factors initiate developmental cascades that carry out the embryonic developmental program. Even after the initiation of zygotic gene expression, perduring maternal products continue performing essential functions, either together with other maternal factors or through interactions with newly expressed zygotic products. Advances in zebrafish research have placed this organism in a unique position to contribute to a detailed understanding of the role of maternal factors in early vertebrate development. This review summarizes our knowledge on the processes involved in the production and redistribution of maternal factors during zebrafish oogenesis and early development, as well as our understanding of the function of these factors in axis formation, germ layer and germ cell specification, and other early embryonic processes.
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Affiliation(s)
- Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin, USA.
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Fürthauer M, Van Celst J, Thisse C, Thisse B. Fgf signalling controls the dorsoventral patterning of the zebrafish embryo. Development 2004; 131:2853-64. [PMID: 15151985 DOI: 10.1242/dev.01156] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The establishment of dorsoventral (DV) patterning in vertebrate embryos depends on the morphogenic activity of a group of Tgfβ superfamily members, the bone morphogenetic proteins (Bmps) (which specify ventral cell fates), and on their interaction with their dorsally secreted cognate inhibitors chordin and noggin. In the zebrafish, genetic analysis has revealed that Bmp2b and Bmp7, as well as their antagonist chordin, are required for proper DV patterning. The expression of Bmp genes is initially activated in the whole blastula. Well before the beginning of gastrulation, Bmp gene expression progressively disappears from the dorsal side to become restricted to the ventral part of the embryo. We show that this early restriction of Bmp gene expression, which occurs independently of noggin and chordin, is an essential step in the establishment of DV patterning. The progressive ventral restriction of Bmp gene transcripts is coincident with the spreading of Fgf activity from the dorsal side of the embryo, suggesting that Fgf signalling is implicated in dorsal downregulation of Bmp gene expression. In accordance with this, activation of the Fgf/Ras/Mapk-signalling pathway inhibits ventral Bmp gene expression, thereby causing a dorsalisation of the embryo. Conversely,inhibition of Fgf signalling causes Bmp gene expression to expand dorsally,leading to an expansion of ventral cell fates. In accordance with an important role of Fgf signalling in the DV patterning of the zebrafish, we show that loss of Fgf8 function enhances the ventralisation of chordin-deficient embryos. Our results thereby demonstrate that pre-gastrula stage Fgf-signalling is essential to delimit the expression domain of the genes encoding the functional morphogen of the dorsoventral axis of the early zebrafish embryo.
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Affiliation(s)
- Maximilian Fürthauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/INSERM/ULP, 1 rue Laurent Fries, BP10142, CU de Strasbourg, 67404, Illkirch Cedex, France
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42
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Wagner DS, Dosch R, Mintzer KA, Wiemelt AP, Mullins MC. Maternal Control of Development at the Midblastula Transition and beyond. Dev Cell 2004; 6:781-90. [PMID: 15177027 DOI: 10.1016/j.devcel.2004.04.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2003] [Revised: 03/29/2004] [Accepted: 03/29/2004] [Indexed: 10/26/2022]
Abstract
Many maternal factors in the oocyte persist in the embryo. They are required to initiate zygotic transcription but also function beyond this stage, where they interact with zygotic gene products during embryonic development. In a four-generation screen in the zebrafish, we identified 47 maternal-effect and five paternal-effect mutants that manifest their phenotypes at the time of, or after, zygotic genome activation. We propagated a subset of 13 mutations that cause developmental arrest at the midblastula transition, defects in cell viability, embryonic morphogenesis, and establishment of the embryonic body plan. This diverse group of mutants, many not previously observed in vertebrates, demonstrates a substantial maternal contribution to the "zygotic" period of embryogenesis and a surprising degree of paternal control. These mutants provide powerful tools to dissect the maternal and paternal control of vertebrate embryogenesis.
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Affiliation(s)
- Daniel S Wagner
- Department of Cell and Developmental Biology, University of Pennsylvania Medical School, 1211 BRBII/III, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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Payne-Ferreira TL, Yelick PC. Alk8 is required for neural crest cell formation and development of pharyngeal arch cartilages. Dev Dyn 2003; 228:683-96. [PMID: 14648845 DOI: 10.1002/dvdy.10417] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The type I TGFbeta family member receptor alk8 acts in bone morphogenetic protein (BMP) signaling pathways to establish dorsoventral patterning in the early zebrafish embryo. Here, we present evidence that alk8 is required for neural crest cell (NCC) formation and that alk8 signaling gradients direct the proper patterning of premigratory NCCs. We extend our previous functional studies of alk8 to demonstrate that ectopic expression of constitutively active and dominant negative Alk8, consistently results in more medially or laterally positioned premigratory NCCs, respectively. We also demonstrate that patterning defects in premigratory NCCs, induced by alk8 misexpression, correlate with subsequent defects in NCC-derived pharyngeal arch cartilages. Furthermore, an anteroposterior effect is revealed, where overexpression of Alk8 more severely affects anterior arch cartilages and decreased Alk8 activity more severely affects posterior arch cartilage formation. Ectopic expression studies of alk8 are supported by analyses of zygotic and maternal-zygotic laf/alk8 mutants and of several BMP pathway mutants. Pharyngeal mesodermal and endodermal defects in laf/alk8 mutants suggest additional roles for alk8 in patterning of these tissues. Our results provide insight into alk8-mediated BMP signaling gradients and the establishment of premigratory NCC mediolateral positioning, and extend the model for BMP patterning of the neural crest to include that of NCC-derived pharyngeal arch cartilages.
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Affiliation(s)
- T L Payne-Ferreira
- Department of Cytokine Biology, The Forsyth Institute, Boston, Massachusetts 02115, USA
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Martyn U, Schulte-Merker S. The ventralized ogon mutant phenotype is caused by a mutation in the zebrafish homologue of Sizzled, a secreted Frizzled-related protein. Dev Biol 2003; 260:58-67. [PMID: 12885555 DOI: 10.1016/s0012-1606(03)00221-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The BMP signaling pathway plays a key role during dorsoventral pattern formation of vertebrate embryos. In zebrafish, all cloned mutants affecting this process are deficient in members of the BMP pathway. In a search for factors differentially expressed in swirl/bmp2b mutants compared with wild type, we isolated zebrafish Sizzled, a member of the secreted Frizzled-related protein family and putative Wnt inhibitor. The knockdown of sizzled using antisense morpholino phenocopied the ventralized mutant ogon (formerly also known as mercedes and short tail). By sequencing and rescue experiments, we demonstrate that ogon encodes sizzled. Overexpression of sizzled, resulting in strongly dorsalized phenotypes, and the expression domains of sizzled in wild type embryos, localized in the ventral side during gastrulation and restricted to the posterior end during segmentation stages, correlate with its role in dorsoventral patterning. The expanded expression domain of sizzled in ogon and chordino together with its downregulation in swirl suggests a BMP2b-dependent negative autoregulation of sizzled. Indicating a novel role for a secreted Frizzled-related protein, we show that, in addition to the BMP pathway, a component of the Wnt signaling pathway is required for dorsoventral pattern formation in zebrafish.
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Affiliation(s)
- Ulrike Martyn
- Exelixis Deutschland GmbH, Spemannstrasse 35, 72076 Tübingen, Germany
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45
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Yabe T, Shimizu T, Muraoka O, Bae YK, Hirata T, Nojima H, Kawakami A, Hirano T, Hibi M. Ogon/Secreted Frizzled functions as a negative feedback regulator of Bmp signaling. Development 2003; 130:2705-16. [PMID: 12736214 DOI: 10.1242/dev.00506] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The zebrafish mutant ogon (also called mercedes and short tail) displays ventralized phenotypes similar to the chordino (dino) mutant, in which the gene for the Bmp antagonist Chordin is mutated. We isolated the gene responsible for ogon by a positional cloning strategy and found that the ogon locus encodes a zebrafish homolog of Secreted Frizzled (Sizzled), which has sequence similarity to a Wnt receptor, Frizzled. Unlike other secreted Frizzled-related proteins (sFrps) and the Wnt inhibitor Dickkopf1, the misexpression of Ogon/Sizzled dorsalized, but did not anteriorize, the embryos, suggesting a role for Ogon/Sizzled in Bmp inhibition. Ogon/Sizzled did not inhibit a Wnt8-dependent transcription in the zebrafish embryo. ogon/sizzled was expressed on the ventral side from the late blastula through the gastrula stages. The ventral ogon/sizzled expression in the gastrula stage was reduced or absent in the swirl/bmp2b mutants but expanded in the chordino mutants. Misexpression of ogon/sizzled did not dorsalize the chordino mutants, suggesting that Ogon/Sizzled required Chordin protein for dorsalization and Bmp inhibition. These data indicate that Ogon/Sizzled functions as a negative regulator of Bmp signaling and reveal a novel role for a sFrp in dorsoventral patterning.
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Affiliation(s)
- Taijiro Yabe
- Department of Molecular Oncology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
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Abstract
The ability of an animal to carry out its normal behavioral repertoire requires generation of an enormous diversity of neurons and glia. The relative simplicity of the spinal cord makes this an especially attractive part of the nervous system for addressing questions about the development of vertebrate neural specification and function. The last decade has witnessed an explosion in our understanding of spinal cord development and the functional interactions among spinal cord neurons and glia. Cellular, genetic, molecular, physiological and behavioral studies in zebrafish have all been important in providing insights into questions that remained unanswered by studies from other vertebrate model organisms. This is the case because many zebrafish spinal neurons can be individually identified and followed over time in living embryos and larvae. In this review, we discuss what is currently known about the cellular, genetic and molecular mechanisms involved in specifying distinct cell types in the zebrafish spinal cord and how these cells establish the functional circuitry that mediates particular behaviors. We start by describing the early signals and morphogenetic movements that form the nervous system, and in particular, the spinal cord. We then provide an overview of the cell types within the spinal cord and describe how they are specified and patterned. We begin ventrally with floor plate and proceed dorsally, through motoneurons and oligodendrocytes, interneurons, astrocytes and radial glia, spinal sensory neurons and neural crest. We next describe axon pathfinding of spinal neurons. Finally, we discuss the roles of particular spinal cord neurons in specific behaviors.
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Affiliation(s)
- Katharine E Lewis
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403, USA.
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47
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Maternally Supplied Smad5 Is Required for Ventral Specification in Zebrafish Embryos Prior to Zygotic Bmp Signaling. Dev Biol 2002. [DOI: 10.1006/dbio.2002.0805] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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48
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Lieschke GJ, Oates AC, Paw BH, Thompson MA, Hall NE, Ward AC, Ho RK, Zon LI, Layton JE. Zebrafish SPI-1 (PU.1) marks a site of myeloid development independent of primitive erythropoiesis: implications for axial patterning. Dev Biol 2002; 246:274-95. [PMID: 12051816 DOI: 10.1006/dbio.2002.0657] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mammalian transcription factor SPI-1 (synonyms: SPI1, PU.1, or Sfpi1) plays a critical role in myeloid development. To examine early myeloid commitment in the zebrafish embryo, we isolated a gene from zebrafish that is a SPI-1 orthologue on the basis of homology and phylogenetic considerations. The zebrafish spi1 (pu1) gene was first expressed at 12 h postfertilization in rostral lateral plate mesoderm (LPM), anatomically isolated from erythroid development in caudal lateral plate mesoderm. Fate-mapping traced rostral LPM cells from the region of initial spi1 expression to a myeloid fate. spi1 expression was lost in the bloodless mutant cloche, but rostral spi1 expression and myeloid development were preserved in the mutant spadetail, despite its complete erythropoietic failure. This dissociation of myeloid and erythroid development was further explored in studies of embryos overexpressing BMP-4, or chordin, in bmp-deficient swirl and snailhouse mutants, and chordin-deficient chordino mutants. These studies demonstrate that, in zebrafish, spi1 marks a rostral population of LPM cells committed to a myeloid fate anatomically separated from and developmentally independent of erythroid commitment in the caudal LPM. Such complete anatomical and developmental dissociation of two hematopoietic lineages adds an interesting complexity to the understanding of vertebrate hematopoietic development and presents significant implications for the mechanisms regulating axial patterning.
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Affiliation(s)
- Graham J Lieschke
- Ludwig Institute for Cancer Research, The Royal Melbourne Hospital, Parkville, Victoria, 3050, Australia.
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49
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Wagner DS, Mullins MC. Modulation of BMP activity in dorsal-ventral pattern formation by the chordin and ogon antagonists. Dev Biol 2002; 245:109-23. [PMID: 11969259 DOI: 10.1006/dbio.2002.0614] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We analyzed the interactions between mutations in antagonistic BMP pathway signaling components to examine the roles that the antagonists play in regulating BMP signaling activity. The dorsalized mutants swirl/bmp2b, snailhouse/bmp7, lost-a-fin/alk8, and mini fin/tolloid were each analyzed in double mutant combinations with the ventralized mutants chordino/chordin and ogon, whose molecular nature is not known. Similar to the BMP antagonist chordino, we found that the BMP ligand mutants swirl/bmp2b and snailhouse/bmp7 are also epistatic to the putative BMP pathway antagonist, ogon, excluding a class of intracellular antagonists as candidates for ogon. In ogon;mini fin double mutants, we observed a mutual suppression of the ogon and mini fin mutant phenotypes, frequently to a wild type phenotype. Thus, the Tolloid/Mini fin metalloprotease that normally cleaves and inhibits Chordin activity is dispensable, when Ogon antagonism is reduced. These results suggest that Ogon encodes a Tolloid and Chordin-independent antagonistic function. By analyzing genes whose expression is very sensitive to BMP signaling levels, we found that the absence of Ogon or Chordin antagonism did not increase the BMP activity remaining in swirl/bmp2b or hypomorphic snailhouse/bmp7 mutants. These results, together with other studies, suggest that additional molecules or mechanisms are essential in generating the presumptive gastrula BMP activity gradient that patterns the dorsal-ventral axis. Lastly we observed a striking increased penetrance of the swirl/bmp2b dominant dorsalized phenotype, when Chordin function is also absent. Loss of the BMP antagonist Chordin is expected to increase BMP signaling levels in a swirl heterozygote, but instead we observed an apparent decrease in BMP signaling levels and a loss of ventral tail tissue. As has been proposed for the fly orthologue of chordin, short gastrulation, our paradoxical results can be explained by a model whereby Chordin both antagonizes and promotes BMP activity.
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Affiliation(s)
- Daniel S Wagner
- Department of Cell and Developmental Biology, University of Pennsylvania Medical School, Philadelphia, PA 19104, USA
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50
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Muñoz-Sanjuán I, Brivanlou AH. Neural induction, the default model and embryonic stem cells. Nat Rev Neurosci 2002; 3:271-80. [PMID: 11967557 DOI: 10.1038/nrn786] [Citation(s) in RCA: 417] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Ignacio Muñoz-Sanjuán
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, New York, New York 10021, USA
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