151
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Katanaev VL, Kryuchkov MV. The eye of Drosophila as a model system for studying intracellular signaling in ontogenesis and pathogenesis. BIOCHEMISTRY (MOSCOW) 2012; 76:1556-81. [DOI: 10.1134/s0006297911130116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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152
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Zhang P, Wu Y, Belenkaya TY, Lin X. SNX3 controls Wingless/Wnt secretion through regulating retromer-dependent recycling of Wntless. Cell Res 2011; 21:1677-90. [PMID: 22041890 PMCID: PMC3357989 DOI: 10.1038/cr.2011.167] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/19/2011] [Accepted: 09/26/2011] [Indexed: 11/25/2022] Open
Abstract
Drosophila Wingless (Wg) acts as a morphogen during development. Wg secretion is controlled by a seven-pass transmembrane cargo Wntless (Wls). We have recently identified retromer as a key regulator involved in Wls trafficking. As sorting nexin (SNX) molecules are essential components of the retromer complex, we hypothesized that specific SNX(s) is required for retromer-mediated Wnt secretion. Here, we generated Drosophila mutants for all of the eight snx members, and identified Drosophila SNX3 (DSNX3) as an essential molecule required for Wg secretion. We show that Wg secretion and its signaling activity are defective in Dsnx3 mutant clones in wing discs. Wg levels in the culture medium of Dsnx3-depleted S2 cells are also markedly reduced. Importantly, Wls levels are strikingly reduced in Dsnx3 mutant cells, and overexpression of Wls can rescue the Wg secretion defect observed in Dsnx3 mutant cells. Moreover, DSNX3 can interact with the retromer component Vps35, and co-localize with Vps35 in early endosomes. These data indicate that DSNX3 regulates Wg secretion via retromer-dependent Wls recycling. In contrast, we found that Wg secretion is not defective in cells mutant for Drosophila snx1 and snx6, two components of the classical retromer complex. Ectopic expression of DSNX1 or DSNX6 fails to rescue the Wg secretion defect in Dsnx3 mutant wing discs and in Dsnx3 dsRNA-treated S2 cells. These data demonstrate the specificity of the DSNX3-retromer complex in Wls recycling. Together, our findings suggest that DSNX3 acts as a cargo-specific component of retromer, which is required for endocytic recycling of Wls and Wg/Wnt secretion.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, and Key Laboratory of Stem Cell and Developmental Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yihui Wu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, and Key Laboratory of Stem Cell and Developmental Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tatyana Y Belenkaya
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Xinhua Lin
- State Key Laboratory of Biomembrane and Membrane Biotechnology, and Key Laboratory of Stem Cell and Developmental Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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153
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Weisinger K, Kohl A, Kayam G, Monsonego-Ornan E, Sela-Donenfeld D. Expression of hindbrain boundary markers is regulated by FGF3. Biol Open 2011; 1:67-74. [PMID: 23213398 PMCID: PMC3507201 DOI: 10.1242/bio.2011032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Compartment boundaries act as organizing centers that segregate adjacent areas into domains of gene expression and regulation, and control their distinct fates via the secretion of signalling factors. During hindbrain development, a specialized cell-population forms boundaries between rhombomeres. These boundary cells demonstrate unique morphological properties and express multiple genes that differs them from intra-rhombomeric cells. Yet, little is known regarding the mechanisms that controls the expression or function of these boundary markers.Multiple components of the FGF signaling system, including ligands, receptors, downstream effectors as well as proteoglycans are shown to localize to boundary cells in the chick hindbrain. These patterns raise the possibility that FGF signaling plays a role in regulating boundary properties. We provide evidence to the role of FGF signaling, particularly the boundary-derived FGF3, in regulating the expression of multiple markers at hindbrain boundaries. These findings enable further characterization of the unique boundary-cell population, and expose a new function for FGFs as regulators of boundary-gene expression in the chick hindbrain.
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154
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Ogiso Y, Tsuneizumi K, Masuda N, Sato M, Tabata T. Robustness of the Dpp morphogen activity gradient depends on negative feedback regulation by the inhibitory Smad, Dad. Dev Growth Differ 2011; 53:668-78. [PMID: 21671915 DOI: 10.1111/j.1440-169x.2011.01274.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Developmental patterning relies on morphogen concentration gradients, which generally provide invariable positional information despite genetic fluctuations. Theoretical studies have predicted robust patterning; however, little experimental evidence exists to support this idea. In this report, we examine the robustness of the Decapentaplegic (Dpp) (a Drosophila homologue of bone morphogenetic protein [BMP]) activity gradient in the presence of fluctuations in Dpp receptor levels. Dpp activity can be measured by the degree of phosphorylation of Mothers against dpp (Mad), a major signal transducer. We determined that phosphorylated Mad (pMad) levels remain constant when an extra copy of thickveins (tkv), which encodes the receptor, is introduced into the wild-type background. Higher Tkv levels, expressed under the control of an artificial promoter, result in constant pMad levels. This prompted us to study the mechanisms that underlie pMad level maintenance even when Tkv levels are increased. We focused on the inhibitory Smad, daughters against dpp (dad), which is induced by Dpp signaling and negatively regulates Dpp activity. In the absence of dad, pMad levels significantly increase when Tkv levels increase. These results suggest that Dpp activity gradient robustness when Tkv levels increase depends, at least in part, on negative feedback regulation by dad.
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Affiliation(s)
- Yuri Ogiso
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan
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155
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Kanodia JS, Kim Y, Tomer R, Khan Z, Chung K, Storey JD, Lu H, Keller PJ, Shvartsman SY. A computational statistics approach for estimating the spatial range of morphogen gradients. Development 2011; 138:4867-74. [PMID: 22007136 DOI: 10.1242/dev.071571] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A crucial issue in studies of morphogen gradients relates to their range: the distance over which they can act as direct regulators of cell signaling, gene expression and cell differentiation. To address this, we present a straightforward statistical framework that can be used in multiple developmental systems. We illustrate the developed approach by providing a point estimate and confidence interval for the spatial range of the graded distribution of nuclear Dorsal, a transcription factor that controls the dorsoventral pattern of the Drosophila embryo.
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Affiliation(s)
- Jitendra S Kanodia
- Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
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156
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Mii Y, Taira M. Secreted Wnt "inhibitors" are not just inhibitors: regulation of extracellular Wnt by secreted Frizzled-related proteins. Dev Growth Differ 2011; 53:911-23. [PMID: 21995331 DOI: 10.1111/j.1440-169x.2011.01299.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Gradient formation and signaling ranges of secreted proteins are crucial problems to understand how morphogens work for positional information and patterning in animal development. Yet, extracellular behaviors of secreted signaling molecules remain unexplored compared to their downstream pathways inside the cell. Recent advances in bioimaging make it possible to directly visualize morphogen molecules, and this simple strategy has, at least partly, succeeded in uncovering molecular behaviors of morphogens, such as Wnt (wingless-type MMTV integration site family member) and BMP (bone morphogenetic protein) as well as secreted Wnt binding proteins, sFRPs (secreted Frizzled-related proteins), in embryonic tissues. Here, we review the regulation of Wnt signaling by sFRPs, focusing on extracellular regulation of Wnt ligands in comparison with other morphogens. We also discuss evolutionary aspects with comprehensive syntenic and phylogenetic information about vertebrate sfrp genes. We newly annotated several sfrp genes including sfrp2-like 1 (sfrp2l1) in frogs and fishes and crescent in mammals.
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Affiliation(s)
- Yusuke Mii
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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157
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Muratov CB, Gordon PV, Shvartsman SY. Self-similar dynamics of morphogen gradients. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:041916. [PMID: 22181184 DOI: 10.1103/physreve.84.041916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/11/2011] [Indexed: 05/31/2023]
Abstract
Morphogen gradients are concentration fields of molecules acting as spatial regulators of cell differentiation in developing tissues and play a fundamental role in various aspects of embryonic development. We discovered a family of self-similar solutions in a canonical class of nonlinear reaction-diffusion models describing the formation of morphogen gradients. These solutions are realized in the limit of infinitely high production rate at the tissue boundary and are given by the product of the steady state concentration profile and a function of the diffusion similarity variable. We solved the boundary value problem for the similarity profile numerically and analyzed the implications of the discovered self-similarity on the dynamics of morphogenetic patterning.
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Affiliation(s)
- Cyrill B Muratov
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
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158
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Abstract
The regulation of organ size is a long-standing problem in animal development. Studies in this area have shown that organ-intrinsic patterning morphogens influence organ size, guiding growth in accordance with positional information. However, organ-extrinsic humoral factors such as insulin also affect organ size, synchronizing growth with nutrient levels. Proliferating cells must integrate instructions from morphogens with those from nutrition so that growth proceeds as a function of both inputs. Coordinating cell proliferation with morphogens and nutrients ensures organs scale appropriately with body size, but the basis of this coordination is unclear. Here, the problem is illustrated using the Drosophila wing--a paradigm for organ growth and size control--and a potential solution suggested.
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Affiliation(s)
- Joseph Parker
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA.
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159
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Dodla MC, Young A, Venable A, Hasneen K, Rao RR, Machacek DW, Stice SL. Differing lectin binding profiles among human embryonic stem cells and derivatives aid in the isolation of neural progenitor cells. PLoS One 2011; 6:e23266. [PMID: 21850265 PMCID: PMC3151296 DOI: 10.1371/journal.pone.0023266] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 07/14/2011] [Indexed: 11/25/2022] Open
Abstract
Human embryonic stem cells (hESCs) and their differentiated progeny allow for investigation of important changes/events during normal embryonic development. Currently most of the research is focused on proteinacous changes occurring as a result of differentiation of stem cells and little is known about changes in cell surface glycosylation patterns. Identification of cell lineage specific glycans can help in understanding their role in maintenance, proliferation and differentiation. Furthermore, these glycans can serve as markers for isolation of homogenous populations of cells. Using a panel of eight biotinylated lectins, the glycan expression of hESCs, hESCs-derived human neural progenitors (hNP) cells, and hESCs-derived mesenchymal progenitor (hMP) cells was investigated. Our goal was to identify glycans that are unique for hNP cells and use the corresponding lectins for cell isolation. Flow cytometry and immunocytochemistry were used to determine expression and localization of glycans, respectively, in each cell type. These results show that the glycan expression changes upon differentiation of hESCs and is different for neural and mesenchymal lineage. For example, binding of PHA-L lectin is low in hESCs (14±4.4%) but significantly higher in differentiated hNP cells (99±0.4%) and hMP cells (90±3%). Three lectins: VVA, DBA and LTL have low binding in hESCs and hMP cells, but significantly higher binding in hNP cells. Finally, VVA lectin binding was used to isolate hNP cells from a mixed population of hESCs, hNP cells and hMP cells. This is the first report that compares glycan expression across these human stem cell lineages and identifies significant differences. Also, this is the first study that uses VVA lectin for isolation for human neural progenitor cells.
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Affiliation(s)
- Mahesh C. Dodla
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, United States of America
| | - Amber Young
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, United States of America
| | - Alison Venable
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Kowser Hasneen
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, United States of America
| | - Raj R. Rao
- Department of Chemical and Life Sciences Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | | | - Steven L. Stice
- Regenerative Bioscience Center, University of Georgia, Athens, Georgia, United States of America
- ArunA Biomedical Inc., Athens, Georgia, United States of America
- * E-mail:
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160
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Morata G, Shlevkov E, Pérez-Garijo A. Mitogenic signaling from apoptotic cells in Drosophila. Dev Growth Differ 2011; 53:168-76. [PMID: 21338343 DOI: 10.1111/j.1440-169x.2010.01225.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apoptotic cells of Drosophila not only activate caspases, but also are able to secrete developmental signals like Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless (Wg) before dying. Since Dpp and Wg are secreted in growing tissues and behave as growth factors, it was proposed that they play a role in compensatory proliferation, the process by which a growing blastema can restore normal size after massive apoptosis. We discuss recent results showing that there is normal compensatory proliferation in the absence of Dpp/Wg signaling, thus indicating it has no significant role in the process. Furthermore, we argue that Dpp/Wg signaling is not a resident feature of apoptotic cells, but a side effect of the necessary activation of the JNK pathway. Nevertheless, the ectopic JNK/Dpp/Wg signaling may have an important role in tissue regeneration. Recent work in other organisms suggests that paracrine signaling from apoptotic cells may be of general significance in wound healing and tissue regeneration in metazoans.
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Affiliation(s)
- Ginés Morata
- Center for Molecular Biology, Council for Scientific Research-Madrid Autonomous University, Nicolás Cabrera 1, 28049, Madrid, Spain.
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161
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Takemura M, Adachi-Yamada T. Repair responses to abnormalities in morphogen activity gradient. Dev Growth Differ 2011; 53:161-7. [PMID: 21338342 DOI: 10.1111/j.1440-169x.2011.01249.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Establishing and maintaining a morphogen gradient are important in the growth and patterning of developing organs. When a discontinuity in a morphogen signal gradient is created by somatic mutant clones with aberrant intensities of morphogen signals within the Drosophila wing disc, the clones can be removed by apoptosis to restore the morphogen signal gradient. This apoptosis is termed "morphogenetic apoptosis" and has been observed to occur in a cell autonomous or non-cell autonomous manner. This review discusses possible molecular mechanisms of both autonomous and non-cell autonomous apoptosis in addition to similar cellular events in reference to recent findings.
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Affiliation(s)
- Masahiko Takemura
- Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
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162
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Trepat X, Fredberg JJ. Plithotaxis and emergent dynamics in collective cellular migration. Trends Cell Biol 2011; 21:638-46. [PMID: 21784638 DOI: 10.1016/j.tcb.2011.06.006] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/15/2011] [Accepted: 06/17/2011] [Indexed: 11/27/2022]
Abstract
For a monolayer sheet to migrate cohesively, it has long been suspected that each constituent cell must exert physical forces not only upon its extracellular matrix but also upon neighboring cells. The first comprehensive maps of these distinct force components reveal an unexpected physical picture. Rather than showing smooth and systematic variation within the monolayer, the distribution of physical forces is dominated by heterogeneity, both in space and in time, which emerges spontaneously, propagates over great distances, and cooperates over the span of many cell bodies. To explain the severe ruggedness of this force landscape and its role in collective cell guidance, the well known mechanisms of chemotaxis, durotaxis, haptotaxis are clearly insufficient. In a broad range of epithelial and endothelial cell sheets, collective cell migration is governed instead by a newly discovered emergent mechanism of innately collective cell guidance - plithotaxis.
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Affiliation(s)
- Xavier Trepat
- Institute for Bioengineering of Catalonia, Ciber Enfermedades Respiratorias, University of Barcelona, Spain.
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163
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Wojcinski A, Nakato H, Soula C, Glise B. DSulfatase-1 fine-tunes Hedgehog patterning activity through a novel regulatory feedback loop. Dev Biol 2011; 358:168-80. [PMID: 21806980 DOI: 10.1016/j.ydbio.2011.07.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/20/2011] [Accepted: 07/16/2011] [Indexed: 01/25/2023]
Abstract
Sulfs are secreted sulfatases that catalyse removal of sulfate from Heparan Sulfate Proteoglycans (HSPGs) in the extracellular space. These enzymes are well known to regulate a number of crucial signalling pathways during development. In this study, we report that DSulfatase-1 (DSulf1), the unique Drosophila Sulf protein, is a regulator of Hedgehog (Hh) signalling during wing development. DSulf1 activity is required in both Hh source and Hh receiving cells for proper positioning of Hh target gene expression boundaries. As assessed by loss- and gain-of-function experiments in specific compartments, DSulf1 displays dual functions with respect to Hh signalling, acting as a positive regulator in Hh producing cells and a negative regulator in Hh receiving cells. In either domain, DSulf1 modulates Hh distribution by locally lowering the concentration of the morphogen at the apical pole of wing disc cells. Thus, we propose that DSulf1, by its desulfation catalytic activity, lowers Hh/HSPG interaction in both Hh source and target fields, thereby enhancing Hh release from its source of production and reducing Hh signalling activity in responding cells. Finally, we show that Dsulf1 pattern of expression is temporally regulated and depends on EGFR signalling, a Hh-dependent secondary signal in this tissue. Our data reveal a novel Hh regulatory feedback loop, involving DSulf1, which contributes to maintain and stabilise expression domains of Hh target genes during wing disc development.
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Affiliation(s)
- Alexandre Wojcinski
- Université de Toulouse, UPS, CNRS, Centre de Biologie du Développement, 118. route de Narbonne, F-31062 Toulouse, France
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164
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Malinauskas T, Aricescu AR, Lu W, Siebold C, Jones EY. Modular mechanism of Wnt signaling inhibition by Wnt inhibitory factor 1. Nat Struct Mol Biol 2011; 18:886-93. [PMID: 21743455 DOI: 10.1038/nsmb.2081] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 05/06/2011] [Indexed: 01/12/2023]
Abstract
Wnt morphogens control embryonic development and homeostasis in adult tissues. In vertebrates the N-terminal WIF domain (WIF-1(WD)) of Wnt inhibitory factor 1 (WIF-1) binds Wnt ligands. Our crystal structure of WIF-1(WD) reveals a previously unidentified binding site for phospholipid; two acyl chains extend deep into the domain, and the head group is exposed to the surface. Biophysical and cellular assays indicate that there is a WIF-1(WD) Wnt-binding surface proximal to the lipid head group but also implicate the five epidermal growth factor (EGF)-like domains (EGFs I-V) in Wnt binding. The six-domain WIF-1 crystal structure shows that EGFs I-V are wrapped back, interfacing with WIF-1(WD) at EGF III. EGFs II-V contain a heparan sulfate proteoglycan (HSPG)-binding site, consistent with conserved positively charged residues on EGF IV. This combination of HSPG- and Wnt-binding properties suggests a modular model for the localization of WIF-1 and for signal inhibition within morphogen gradients.
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Affiliation(s)
- Tomas Malinauskas
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
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165
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Abstract
In this report, we develop smart surfaces for the spatial and temporal control of mammalian cell behavior. We integrate a bioactive surface strategy with a photo-electroactive surface strategy to generate dynamic ligand surface gradients for controlling cell adhesion, tissue shape morphing, and cell tissue migration.
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Affiliation(s)
- Wei Luo
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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166
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Lee KL, Lim SK, Orlov YL, Yit LY, Yang H, Ang LT, Poellinger L, Lim B. Graded Nodal/Activin signaling titrates conversion of quantitative phospho-Smad2 levels into qualitative embryonic stem cell fate decisions. PLoS Genet 2011; 7:e1002130. [PMID: 21731500 PMCID: PMC3121749 DOI: 10.1371/journal.pgen.1002130] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/01/2011] [Indexed: 12/11/2022] Open
Abstract
Nodal and Activin are morphogens of the TGFbeta superfamily of signaling molecules that direct differential cell fate decisions in a dose- and distance-dependent manner. During early embryonic development the Nodal/Activin pathway is responsible for the specification of mesoderm, endoderm, node, and mesendoderm. In contradiction to this drive towards cellular differentiation, the pathway also plays important roles in the maintenance of self-renewal and pluripotency in embryonic and epiblast stem cells. The molecular basis behind stem cell interpretation of Nodal/Activin signaling gradients and the undertaking of disparate cell fate decisions remains poorly understood. Here, we show that any perturbation of endogenous signaling levels in mouse embryonic stem cells leads to their exit from self-renewal towards divergent differentiation programs. Increasing Nodal signals above basal levels by direct stimulation with Activin promotes differentiation towards the mesendodermal lineages while repression of signaling with the specific Nodal/Activin receptor inhibitor SB431542 induces trophectodermal differentiation. To address how quantitative Nodal/Activin signals are translated qualitatively into distinct cell fates decisions, we performed chromatin immunoprecipitation of phospho-Smad2, the primary downstream transcriptional factor of the Nodal/Activin pathway, followed by massively parallel sequencing, and show that phospho-Smad2 binds to and regulates distinct subsets of target genes in a dose-dependent manner. Crucially, Nodal/Activin signaling directly controls the Oct4 master regulator of pluripotency by graded phospho-Smad2 binding in the promoter region. Hence stem cells interpret and carry out differential Nodal/Activin signaling instructions via a corresponding gradient of Smad2 phosphorylation that selectively titrates self-renewal against alternative differentiation programs by direct regulation of distinct target gene subsets and Oct4 expression.
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Affiliation(s)
- Kian Leong Lee
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- * E-mail: (KLL); –star.edu.sg (BL)
| | - Sandy Keat Lim
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Yuriy Lvovich Orlov
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Le Yau Yit
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Henry Yang
- Singapore Immunology Network, Agency for Science, Technology, and Research, Singapore, Singapore
| | - Lay Teng Ang
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
| | - Lorenz Poellinger
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bing Lim
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- Beth Israel Deaconess Medical Centre, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (KLL); –star.edu.sg (BL)
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167
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Miyashima S, Koi S, Hashimoto T, Nakajima K. Non-cell-autonomous microRNA165 acts in a dose-dependent manner to regulate multiple differentiation status in the Arabidopsis root. Development 2011; 138:2303-13. [DOI: 10.1242/dev.060491] [Citation(s) in RCA: 221] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the development of multicellular organisms, cell fate is usually determined by exchanging positional information. Animals employ a class of intercellular signaling molecules that specify different cell fates by their dosage, but the existence of an equivalent system has not been demonstrated in plants, except that the growth regulator auxin has been proposed to act in a similar manner in certain developmental contexts. Recently, it has been reported that, in the Arabidopsis root meristem, endodermis-derived microRNA (miR) 165/166 non-cell-autonomously suppress the expression of the Class III HD-ZIP transcription factor PHABULOSA (PHB) in the peripheral stele, thereby specifying xylem differentiation. Here, we show that the miR165/166-dependent suppression of PHB is required not only for xylem specification, but also for differentiation of the pericycle, as well as for ground tissue patterning. Furthermore, using a plant system that allows quantitative control of miR165 production in the ground tissue, we show that endodermis-derived miR165 acts in a dose-dependent manner to form a graded distribution of PHB transcripts across the stele. These results reveal a previously unidentified role of miR165 in the differentiation of a broad range of root cell types and suggest that endodermis-derived miR165 acts in a dose-dependent manner to control multiple differentiation status in the Arabidopsis root.
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Affiliation(s)
- Shunsuke Miyashima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Satoshi Koi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Takashi Hashimoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Keiji Nakajima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
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168
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Abstract
G protein-coupled receptors (GPCRs) represent the biggest transmembrane receptor family. The Frizzled group of GPCRs is evolutionarily conserved and serves to transduce signals from the Wnt-type lipoglycoprotein growth factors. The Wnt/Frizzled signaling cascades are repeatedly used during animal development and are mostly silent in the adult. Improper activation of these cascades, e.g. through somatic mutation, underlies cancer development in various tissues. Our research over the past years has identified the trimeric G proteins as crucial transducers of the Wnt/Frizzled cascades in insect and mammalian cells. The current mini-review summarizes our findings on the role of G proteins in Wnt/Frizzled signaling, as well as on identification of other signaling intermediates in this physiologically and pathologically important type of intracellular signal transduction.
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Affiliation(s)
- V L Katanaev
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
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169
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Berezhkovskii AM, Sample C, Shvartsman SY. Formation of morphogen gradients: local accumulation time. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:051906. [PMID: 21728570 PMCID: PMC4957404 DOI: 10.1103/physreve.83.051906] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 10/12/2010] [Indexed: 05/31/2023]
Abstract
Spatial regulation of cell differentiation in embryos can be provided by morphogen gradients, which are defined as the concentration fields of molecules that control gene expression. For example, a cell can use its surface receptors to measure the local concentration of an extracellular ligand and convert this information into a corresponding change in its transcriptional state. We characterize the time needed to establish a steady-state gradient in problems with diffusion and degradation of locally produced chemical signals. A relaxation function is introduced to describe how the morphogen concentration profile approaches its steady state. This function is used to obtain a local accumulation time that provides a time scale that characterizes relaxation to steady state at an arbitrary position within the patterned field. To illustrate the approach we derive local accumulation times for a number of commonly used models of morphogen gradient formation.
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Affiliation(s)
- Alexander M Berezhkovskii
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, USA
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170
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Tostevin F. Precision of sensing cell length via concentration gradients. Biophys J 2011; 100:294-303. [PMID: 21244825 DOI: 10.1016/j.bpj.2010.11.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/25/2010] [Accepted: 11/16/2010] [Indexed: 11/19/2022] Open
Abstract
Unicellular organisms are typically found to have a characteristic cell size. To achieve a homeostatic distribution of cell sizes over many generations requires that cell length is actively sensed and regulated. However, the mechanisms by which cell size is controlled remain poorly understood. Recent experiments in fission yeast have shown that cell length is controlled in part by polar gradients of the protein Pom1 together with localized measurement of concentration at midcell. Dilution as the cell grows leads to a reduction in the midcell protein concentration, which lifts a block on mitosis. Here we analyze the precision of this mechanism for length sensing in the presence of inevitable intrinsic noise in the processes leading to formation and measurement of this gradient. We find that the use of concentration gradients allows for more robust length sensing than a comparable spatially uniform system, and allows for reliable length determination even if the average protein concentration throughout the cell remains constant as the cell grows. Optimal values for the gradient decay length and receptor dissociation constant emerge from maximizing sensitivity while minimizing the impact of density fluctuations.
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171
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Abstract
Some aspects of pattern formation in developing embryos can be described by nonlinear reaction-diffusion equations. An important class of these models accounts for diffusion and degradation of a locally produced single chemical species. At long times, solutions of such models approach a steady state in which the concentration decays with distance from the source of production. We present analytical results that characterize the dynamics of this process and are in quantitative agreement with numerical solutions of the underlying nonlinear equations. The derived results provide an explicit connection between the parameters of the problem and the time needed to reach a steady state value at a given position. Our approach can be used for the quantitative analysis of tissue patterning by morphogen gradients, a subject of active research in biophysics and developmental biology.
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172
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Seirin Lee S, Gaffney EA, Baker RE. The dynamics of Turing patterns for morphogen-regulated growing domains with cellular response delays. Bull Math Biol 2011; 73:2527-51. [PMID: 21347815 DOI: 10.1007/s11538-011-9634-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 01/27/2011] [Indexed: 11/29/2022]
Abstract
Since its conception in 1952, the Turing paradigm for pattern formation has been the subject of numerous theoretical investigations. Experimentally, this mechanism was first demonstrated in chemical reactions over 20 years ago and, more recently, several examples of biological self-organisation have also been implicated as Turing systems. One criticism of the Turing model is its lack of robustness, not only with respect to fluctuations in the initial conditions, but also with respect to the inclusion of delays in critical feedback processes such as gene expression. In this work we investigate the possibilities for Turing patterns on growing domains where the morphogens additionally regulate domain growth, incorporating delays in the feedback between signalling and domain growth, as well as gene expression. We present results for the proto-typical Schnakenberg and Gierer-Meinhardt systems: exploring the dynamics of these systems suggests a reconsideration of the basic Turing mechanism for pattern formation on morphogen-regulated growing domains as well as highlighting when feedback delays on domain growth are important for pattern formation.
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Affiliation(s)
- S Seirin Lee
- Graduate School of Mathematical Sciences, The University of Tokyo, Japan.
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173
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You J, Belenkaya T, Lin X. Sulfated is a negative feedback regulator of wingless in Drosophila. Dev Dyn 2011; 240:640-8. [PMID: 21305649 DOI: 10.1002/dvdy.22562] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2010] [Indexed: 01/21/2023] Open
Abstract
Drosophila Wingless (Wg) acts as a morphogen to control pattern formation in a concentration dependent manner. Previous studies demonstrated important roles of heparan sulfate proteoglycans (HSPGs) in controlling Wg signaling and distribution. Here, we examined the role of Sulfated (Sulf1), a Drosophila homolog of vertebrate heparan sulfate 6-O endosulfatase, in Wg signaling and distribution. We show that sulf1 is specifically up-regulated by Wg signaling in the wing disc. We found that expression of Wg target gene senseless (sens) was elevated in the sulf1 mutant wing discs. Sulf1 also negatively regulate extracellular levels of Wg. Genetic interaction experiments indicate that Wg antagonist Notum may work synergistically with Sulf1 to restrict Wg signaling, and Dally, a member of Drosophila HSPGs, is a potential target of Sulf1. Our results demonstrate that sulf1 is a novel Wg target gene and by a feedback mechanism, it negatively regulated Wg signaling and distribution in vivo.
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174
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Proper formation of whisker barrelettes requires periphery-derived Smad4-dependent TGF-beta signaling. Proc Natl Acad Sci U S A 2011; 108:3395-400. [PMID: 21300867 DOI: 10.1073/pnas.1014411108] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mammalian somatosensory topographic maps contain specialized neuronal structures that precisely recapitulate the spatial pattern of peripheral sensory organs. In the mouse, whiskers are orderly mapped onto several brainstem nuclei as a set of modular structures termed barrelettes. Using a dual-color iontophoretic labeling strategy, we found that the precise topography of barrelettes is not a result of ordered positions of sensory neurons within the ganglion. We next explored another possibility that formation of the whisker map is influenced by periphery-derived mechanisms. During the period of peripheral sensory innervation, several TGF-β ligands are exclusively expressed in whisker follicles in a dynamic spatiotemporal pattern. Disrupting TGF-β signaling, specifically in sensory neurons by conditional deletion of Smad4 at the late embryonic stage, results in the formation of abnormal barrelettes in the principalis and interpolaris brainstem nuclei and a complete absence of barrelettes in the caudalis nucleus. We further show that this phenotype is not derived from defective peripheral innervation or central axon outgrowth but is attributable to the misprojection and deficient segregation of trigeminal axonal collaterals into proper barrelettes. Furthermore, Smad4-deficient neurons develop simpler terminal arbors and form fewer synapses. Together, our findings substantiate the involvement of whisker-derived TGF-β/Smad4 signaling in the formation of the whisker somatotopic maps.
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175
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Interpretation of the FGF8 morphogen gradient is regulated by endocytic trafficking. Nat Cell Biol 2011; 13:153-8. [DOI: 10.1038/ncb2155] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 11/17/2010] [Indexed: 12/25/2022]
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176
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Abstract
Gap genes are involved in segment determination during the early development of the fruit fly Drosophila melanogaster as well as in other insects. This review attempts to synthesize the current knowledge of the gap gene network through a comprehensive survey of the experimental literature. I focus on genetic and molecular evidence, which provides us with an almost-complete picture of the regulatory interactions responsible for trunk gap gene expression. I discuss the regulatory mechanisms involved, and highlight the remaining ambiguities and gaps in the evidence. This is followed by a brief discussion of molecular regulatory mechanisms for transcriptional regulation, as well as precision and size-regulation provided by the system. Finally, I discuss evidence on the evolution of gap gene expression from species other than Drosophila. My survey concludes that studies of the gap gene system continue to reveal interesting and important new insights into the role of gene regulatory networks in development and evolution.
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Affiliation(s)
- Johannes Jaeger
- Centre de Regulació Genòmica, Universtitat Pompeu Fabra, Barcelona, Spain.
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177
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Nahmad M, Stathopoulos A. Establishing positional information through gradient dynamics: a lesson from the Hedgehog signaling pathway. Fly (Austin) 2010; 4:273-7. [PMID: 20699656 DOI: 10.4161/fly.4.4.12677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A long standing question in developmental biology is how morphogen gradients establish positional information during development. Although the existence of gradients and their role in developmental patterning is no longer in doubt, the ability of cells to respond to different morphogen concentrations has been controversial. In the Drosophila wing disc, Hedgehog (Hh) forms a concentration gradient along the anterior-posterior axis and establishes at least three different gene expression patterns. In a recent study, we challenged the prevailing idea that Hh establishes positional information in a dose-dependent manner and proposed a model in which dynamics of the gradient, resulting from the Hh gene network architecture, determines pattern formation in the wing disc. In this Extra View, we discuss further the methodology used in this study, highlight differences between this and other models of developmental patterning, and also present some questions that remain to be answered in this system.
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Affiliation(s)
- Marcos Nahmad
- Department of Control and Dynamical Systems, California Institute of Technology, Pasadena, CA, USA
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178
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Abstract
During development, secreted morphogens such as Wnt, Hedgehog (Hh), and BMP emit from their producing cells in a morphogenetic field, and specify different cell fates in a direct concentration-dependent manner. Understanding how morphogens form their concentration gradients to pattern tissues has been a central issue in developmental biology. Various experimental studies from Drosophila have led to several models to explain the formation of morphogen gradients. Over the past decade, one of the main findings in this field is the characterization of heparan sulfate proteoglycan (HSPG) as an essential regulator for morphogen gradient formation. Genetic and cell biological studies have showed that HSPGs can regulate morphogen activities at various steps including control of morphogen movement, signaling, and intracellular trafficking. Here, we review these data, highlighting recent findings that reveal mechanistic roles of HSPGs in controlling morphogen gradient formation.
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Affiliation(s)
- Dong Yan
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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179
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Abstract
The potential of stem cells in clinics and as a diagnostic tool is still largely unmet, partially due to a lack of in vitro models that efficiently mimic the in vivo stem cell microenvironment-or niche-and thus would allow reproducible propagation of stem cells or their controlled differentiation in vitro. The current methodological challenges in studying and manipulating stem cells have spurred intense development and application of microfabrication and micropatterning technologies in stem cell biology. These approaches can be readily used to dissect the complex molecular interplay of stem cells and their niche and study single-cell behavior in high-throughput. Increased merging of microfabrication with advanced biomaterials technologies may ultimately result in functional artificial niches capable of recapitulating extrinsic stem cell regulation in vitro and on a single-cell level.
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180
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Casali A. Self-induced patched receptor down-regulation modulates cell sensitivity to the hedgehog morphogen gradient. Sci Signal 2010; 3:ra63. [PMID: 20736483 DOI: 10.1126/scisignal.2001059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Morphogens form signaling gradients that control patterning processes during development. Responding cells must perceive and interpret the concentration-dependent information provided by the morphogen to generate precise patterns of gene expression and cell differentiation in developing tissues. Generally, the absolute number of activated, ligand-bound receptors determines cell perception of the morphogen. In contrast, cells interpret the morphogen Hedgehog (Hh) by measuring the ratio of bound to unbound molecules of its receptor Patched (Ptc). This ratio depends on both the Hh concentration and the absolute number of Ptc molecules. Here, I describe a posttranscriptional process that controls the absolute amount of Ptc present in a cell, which regulates gradient interpretation, wherein self-induced receptor down-regulation that is independent of ligand binding dictates the cell response to a morphogen gradient.
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Affiliation(s)
- Andreu Casali
- Institut de Biologia Molecular de Barcelona and Institute for Research in Biomedicine, 08028 Barcelona, Spain.
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181
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Borello U, Pierani A. Patterning the cerebral cortex: traveling with morphogens. Curr Opin Genet Dev 2010; 20:408-15. [DOI: 10.1016/j.gde.2010.05.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 05/03/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
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182
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Griveau A, Borello U, Causeret F, Tissir F, Boggetto N, Karaz S, Pierani A. A novel role for Dbx1-derived Cajal-Retzius cells in early regionalization of the cerebral cortical neuroepithelium. PLoS Biol 2010; 8:e1000440. [PMID: 20668538 PMCID: PMC2910656 DOI: 10.1371/journal.pbio.1000440] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 06/17/2010] [Indexed: 12/03/2022] Open
Abstract
Patterning of the cerebral cortex during embryogenesis depends not only on passive diffusion of morphogens but also on signal delivery by Cajal-Retzius neurons that migrate over long distances. Patterning of the cortical neuroepithelium occurs at early stages of embryonic development in response to secreted molecules from signaling centers. These signals have been shown to establish the graded expression of transcription factors in progenitors within the ventricular zone and to control the size and positioning of cortical areas. Cajal-Retzius (CR) cells are among the earliest generated cortical neurons and migrate from the borders of the developing pallium to cover the cortical primordium by E11.5. We show that molecularly distinct CR subtypes distribute in specific combinations in pallial territories at the time of cortical regionalization. By means of genetic ablation experiments in mice, we report that loss of septum Dbx1-derived CR cells in the rostromedial pallium between E10.5 and E11.5 results in the redistribution of CR subtypes. This leads to changes in the expression of transcription factors within the neuroepithelium and in the proliferation properties of medial and dorsal cortical progenitors. Early regionalization defects correlate with shifts in the positioning of cortical areas at postnatal stages in the absence of alterations of gene expression at signaling centers. We show that septum-derived CR neurons express a highly specific repertoire of signaling factors. Our results strongly suggest that these cells, migrating over long distances and positioned in the postmitotic compartment, signal to ventricular zone progenitors and, thus, function as modulators of early cortical patterning. Patterning of the cerebral cortex occurs early during embryonic development in response to secreted molecules or morphogens produced at signaling centers. These morphogens establish the graded expression of transcription factors (TFs) in progenitor cells and control the size and positioning of cortical areas in the postnatal animal. CR cells are among the earliest born cortical neurons and play a crucial role in cortical lamination. They are generated at signaling centers and migrate over long distances to cover its entire surface. We show that three different CR subtypes distribute in specific proportions in cortical territories. Genetic ablation of one subpopulation leads to a highly dynamic redistribution of the two others. This results in defects in expression of transcription factors and in progenitor cell proliferation, which correlate with the resulting changes in the size and positioning of cortical areas. Given our additional evidence that CR subtypes express specific repertoires of signaling factors, the ablation phenotypes point to a novel early role for CR cells as mediators of cortical patterning and suggest that CR cells are able to signal to progenitor cells. Our data thus add to the conventional model that morphogens act by passive diffusion and point to a strategy of morphogen delivery over long distance by migrating cells.
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Affiliation(s)
- Amélie Griveau
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
| | - Ugo Borello
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
| | - Frédéric Causeret
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
| | - Fadel Tissir
- Developmental Neurobiology, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Nicole Boggetto
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
| | - Sonia Karaz
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
| | - Alessandra Pierani
- CNRS-UMR 7592, Program of Development and Neurobiology, Institut Jacques Monod, Université Paris Diderot, Paris, France
- * E-mail:
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183
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Cooper GM, Miller ED, Decesare GE, Usas A, Lensie EL, Bykowski MR, Huard J, Weiss LE, Losee JE, Campbell PG. Inkjet-based biopatterning of bone morphogenetic protein-2 to spatially control calvarial bone formation. Tissue Eng Part A 2010; 16:1749-59. [PMID: 20028232 DOI: 10.1089/ten.tea.2009.0650] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The purpose of this study was to demonstrate spatial control of osteoblast differentiation in vitro and bone formation in vivo using inkjet bioprinting technology and to create three-dimensional persistent bio-ink patterns of bone morphogenetic protein-2 (BMP-2) and its modifiers immobilized within microporous scaffolds. Semicircular patterns of BMP-2 were printed within circular DermaMatrix human allograft scaffold constructs. The contralateral halves of the constructs were unprinted or printed with BMP-2 modifiers, including the BMP-2 inhibitor, noggin. Printed bio-ink pattern retention was validated using fluorescent or (125)I-labeled bio-inks. Mouse C2C12 progenitor cells cultured on patterned constructs differentiated in a dose-dependent fashion toward an osteoblastic fate in register to BMP-2 patterns. The fidelity of spatial restriction of osteoblastic differentiation at the boundary between neighboring BMP-2 and noggin patterns improved in comparison with patterns without noggin. Acellular DermaMatrix constructs similarly patterned with BMP-2 and noggin were then implanted into a mouse calvarial defect model. Patterns of bone formation in vivo were comparable with patterned responses of osteoblastic differentiation in vitro. These results demonstrate that three-dimensional biopatterning of a growth factor and growth factor modifier within a construct can direct cell differentiation in vitro and tissue formation in vivo in register to printed patterns.
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Affiliation(s)
- Gregory M Cooper
- Division of Plastic Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15224, USA.
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184
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Kleinschmit A, Koyama T, Dejima K, Hayashi Y, Kamimura K, Nakato H. Drosophila heparan sulfate 6-O endosulfatase regulates Wingless morphogen gradient formation. Dev Biol 2010; 345:204-14. [PMID: 20637191 DOI: 10.1016/j.ydbio.2010.07.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 07/06/2010] [Accepted: 07/07/2010] [Indexed: 01/01/2023]
Abstract
Heparan sulfate proteoglycans (HSPGs) play critical roles in the distribution and signaling of growth factors, but the molecular mechanisms regulating HSPG function are poorly understood. Here, we characterized Sulf1, which is a Drosophila member of the HS 6-O endosulfatase class of HS modifying enzymes. Our genetic and biochemical analyses show that Sulf1 acts as a novel regulator of the Wg morphogen gradient by modulating the sulfation status of HS on the cell surface in the developing wing. Sulf1 affects gradient formation by influencing the stability and distribution of Wg. We also demonstrate that expression of Sulf1 is induced by Wg signaling itself. Thus, Sulf1 participates in a feedback loop, potentially stabilizing the shape of the Wg gradient. Our study shows that the modification of HS fine structure provides a novel mechanism for the regulation of morphogen gradients.
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Affiliation(s)
- Adam Kleinschmit
- Department of Genetics, Cell Biology and Development, The University of Minnesota, Minneapolis, MN 55455, USA
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185
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de Castro NP, Rangel MC, Nagaoka T, Salomon DS, Bianco C. Cripto-1: an embryonic gene that promotes tumorigenesis. Future Oncol 2010; 6:1127-42. [DOI: 10.2217/fon.10.68] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Several studies have shown that cell fate regulation during embryonic development and oncogenic transformation share common regulatory mechanisms and signaling pathways. Indeed, an embryonic gene member of the EGF–Cripto-1/FRL1/Cryptic family, Cripto-1, has been implicated in embryogenesis and in carcinogenesis. Cripto-1 together with the TGF-β ligand Nodal is a key regulator of embryonic development and is a marker of undifferentiated human and mouse embryonic stem cells. While Cripto-1 expression is very low in normal adult tissues, Cripto-1 is re-expressed at high levels in several different human tumors, modulating cancer cell proliferation, migration, epithelial-to-mesenchymal transition and stimulating tumor angiogenesis. Therefore, inhibition of Cripto-1 expression using blocking antibodies or antisense expression vectors might be a useful modality not only to target fully differentiated cancer cells but also to target a subpopulation of tumor cells with stem-like characteristics.
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Affiliation(s)
- Nadia Pereira de Castro
- Mammary Biology & Tumorigenesis Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr., Bldg 37 Room 1112, Bethesda, MD 20892, USA
| | - Maria Cristina Rangel
- Mammary Biology & Tumorigenesis Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr., Bldg 37 Room 1112, Bethesda, MD 20892, USA
| | - Tadahiro Nagaoka
- Mammary Biology & Tumorigenesis Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr., Bldg 37 Room 1112, Bethesda, MD 20892, USA
| | - David S Salomon
- Mammary Biology & Tumorigenesis Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Dr., Bldg 37 Room 1112, Bethesda, MD 20892, USA
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186
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Abstract
Morphogen gradients provide embryonic tissues with positional information by inducing target genes at different concentration thresholds and thus at different positions. The Bicoid morphogen gradient in Drosophila melanogaster embryos has recently been analysed quantitatively, yet how it forms remains a matter of controversy. Several biophysical models that rely on production, diffusion and degradation have been formulated to account for the observed dynamics of the Bicoid gradient, but no one model can account for all its characteristics. Here, we discuss how existing data on this gradient fit the various proposed models and what aspects of gradient formation these models fail to explain. We suggest that knowing a few additional parameters, such as the lifetime of Bicoid, would help to identify and develop better models of Bicoid gradient formation.
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Affiliation(s)
- Oliver Grimm
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mathieu Coppey
- Laboratoire Kastler Brossel, Ecole normale supérieure, 46, rue d'Ulm, 75005 Paris, France
| | - Eric Wieschaus
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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187
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Yan D, Wu Y, Yang Y, Belenkaya TY, Tang X, Lin X. The cell-surface proteins Dally-like and Ihog differentially regulate Hedgehog signaling strength and range during development. Development 2010; 137:2033-44. [PMID: 20501592 DOI: 10.1242/dev.045740] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hedgehog (Hh) acts as a morphogen in various developmental contexts to specify distinct cell fates in a concentration-dependent manner. Hh signaling is regulated by two conserved cell-surface proteins: Ig/fibronectin superfamily member Interference hedgehog (Ihog) and Dally-like (Dlp), a glypican that comprises a core protein and heparan sulfate glycosaminoglycan (GAG) chains. Here, we show in Drosophila that the Dlp core protein can interact with Hh and is essential for its function in Hh signaling. In wing discs, overexpression of Dlp increases short-range Hh signaling while reducing long-range signaling. By contrast, Ihog has biphasic activity in Hh signaling in cultured cells: low levels of Ihog increase Hh signaling, whereas high levels decrease it. In wing discs, overexpression of Ihog represses high-threshold targets, while extending the range of low-threshold targets, thus showing opposite effects to Dlp. We further show that Ihog and its family member Boi are required to maintain Hh on the cell surface. Finally, Ihog and Dlp have complementary expression patterns in discs. These data led us to propose that Dlp acts as a signaling co-receptor. However, Ihog might not act as a classic co-receptor; rather, it may act as an exchange factor by retaining Hh on the cell surface, but also compete with the receptor for Hh binding.
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Affiliation(s)
- Dong Yan
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, and The Graduate Program in Molecular and Developmental Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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188
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Crickmore M, Mann RS. A new chisel for sculpting Darwin's endless forms. Nat Cell Biol 2010; 12:528-9. [PMID: 20517301 DOI: 10.1038/ncb0610-528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The distribution of secreted morphogens in a developing organ determines its form by instructing size, shape and pattern. Pentagone has been identified as a secreted factor that controls the distribution of the morphogen Decapentaplegic (Dpp) in the Drosophila melanogaster wing.
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Affiliation(s)
- Michael Crickmore
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, New York, USA.
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189
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Dessaud E, Ribes V, Balaskas N, Yang LL, Pierani A, Kicheva A, Novitch BG, Briscoe J, Sasai N. Dynamic assignment and maintenance of positional identity in the ventral neural tube by the morphogen sonic hedgehog. PLoS Biol 2010; 8:e1000382. [PMID: 20532235 PMCID: PMC2879390 DOI: 10.1371/journal.pbio.1000382] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 04/20/2010] [Indexed: 12/31/2022] Open
Abstract
Morphogens are secreted signalling molecules that act in a graded manner to control the pattern of cellular differentiation in developing tissues. An example is Sonic hedgehog (Shh), which acts in several developing vertebrate tissues, including the central nervous system, to provide positional information during embryonic patterning. Here we address how Shh signalling assigns the positional identities of distinct neuronal subtype progenitors throughout the ventral neural tube. Assays of intracellular signal transduction and gene expression indicate that the duration as well as level of signalling is critical for morphogen interpretation. Progenitors of the ventral neuronal subtypes are established sequentially, with progressively more ventral identities requiring correspondingly higher levels and longer periods of Shh signalling. Moreover, cells remain sensitive to changes in Shh signalling for an extended time, reverting to antecedent identities if signalling levels fall below a threshold. Thus, the duration of signalling is important not only for the assignment but also for the refinement and maintenance of positional identity. Together the data suggest a dynamic model for ventral neural tube patterning in which positional information corresponds to the time integral of Shh signalling. This suggests an alternative to conventional models of morphogen action that rely solely on the level of signalling.
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Affiliation(s)
- Eric Dessaud
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
| | - Vanessa Ribes
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
| | - Nikolaos Balaskas
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
| | - Lin Lin Yang
- Department of Neurobiology, Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Alessandra Pierani
- Institut Jacques Monod, Université Paris Diderot, Program of Development and Neurobiology, Paris, France
| | - Anna Kicheva
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
| | - Bennett G. Novitch
- Department of Neurobiology, Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - James Briscoe
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
| | - Noriaki Sasai
- Developmental Neurobiology, MRC-National Institute for Medical Research, London, United Kingdom
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190
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Robustness of positional specification by the Hedgehog morphogen gradient. Dev Biol 2010; 342:180-93. [PMID: 20363217 DOI: 10.1016/j.ydbio.2010.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 02/25/2010] [Accepted: 03/26/2010] [Indexed: 11/20/2022]
Abstract
Spatial gradients of Hedgehog signalling play a central role in many patterning events during animal development, regulating cell fate determination and tissue growth in a variety of tissues and developmental stages. Experimental evidence suggests that many of the proteins responsible for regulating Hedgehog signalling and transport are themselves targets of Hedgehog signalling, leading to multiple levels of feedback within the system. We use mathematical modelling to analyse how these overlapping feedbacks combine to regulate patterning and potentially enhance robustness in the Drosophila wing imaginal disc. Our results predict that the regulation of Hedgehog transport and stability by glypicans, as well as multiple overlapping feedbacks in the Hedgehog response network, can combine to enhance the robustness of positional specification against variability in Hedgehog levels. We also discuss potential trade-offs between robustness and additional features of the Hedgehog gradient, such as signalling range and size regulation.
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191
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Nishihara S. Glycosyltransferases and Transporters that Contribute to Proteoglycan Synthesis in Drosophila. Methods Enzymol 2010; 480:323-51. [DOI: 10.1016/s0076-6879(10)80015-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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192
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Mii Y, Taira M. Secreted Frizzled-related proteins enhance the diffusion of Wnt ligands and expand their signalling range. Development 2009; 136:4083-8. [PMID: 19906850 DOI: 10.1242/dev.032524] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Secreted Frizzled-related proteins (sFRPs) are thought to negatively modulate Wnt signalling. Although Wnt proteins are thought to diffuse extracellularly and act as morphogens, little is known about the diffusibility of either Wnts or sFRPs. Here we show that Frzb and Crescent (Cres), which are members of the sFRP family, have the ability to regulate the diffusibility and signalling areas of the Wnt ligands Wnt8 and Wnt11. We found, using the Xenopus embryo, that Wnts do not diffuse effectively, whereas Frzb and Cres spread very widely. Interestingly, Frzb and Cres substantially promoted the diffusion of Wnt8 and Wnt11 through extracellular interactions. Importantly, we show that Wnt8 conveyed by sFRPs can activate canonical Wnt signalling despite the function of sFRPs as Wnt inhibitors, suggesting a novel regulatory system for Wnts by sFRPs.
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Affiliation(s)
- Yusuke Mii
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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193
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Yan D, Wu Y, Feng Y, Lin SC, Lin X. The core protein of glypican Dally-like determines its biphasic activity in wingless morphogen signaling. Dev Cell 2009; 17:470-81. [PMID: 19853561 DOI: 10.1016/j.devcel.2009.09.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 07/14/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
Abstract
Dally-like (Dlp) is a glypican-type heparan sulfate proteoglycan (HSPG), containing a protein core and attached glycosaminoglycan (GAG) chains. In Drosophila wing discs, Dlp represses short-range Wingless (Wg) signaling, but activates long-range Wg signaling. Here, we show that Dlp core protein has similar biphasic activity as wild-type Dlp. Dlp core protein can interact with Wg; the GAG chains enhance this interaction. Importantly, we find that Dlp exhibits a biphasic response, regardless of whether its glycosylphosphatidylinositol linkage to the membrane can be cleaved. Rather, the transition from signaling activator to repressor is determined by the relative expression levels of Dlp and the Wg receptor, Frizzled (Fz) 2. Based on these data, we propose that the principal function of Dlp is to retain Wg on the cell surface. As such, it can either compete with the receptor or provide ligands to the receptor, depending on the ratios of Wg, Fz2, and Dlp.
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Affiliation(s)
- Dong Yan
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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194
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Baena-Lopez LA, Franch-Marro X, Vincent JP. Wingless promotes proliferative growth in a gradient-independent manner. Sci Signal 2009; 2:ra60. [PMID: 19809090 DOI: 10.1126/scisignal.2000360] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Morphogens form concentration gradients that organize patterns of cells and control growth. It has been suggested that, rather than the intensity of morphogen signaling, it is its gradation that is the relevant modulator of cell proliferation. According to this view, the ability of morphogens to regulate growth during development depends on their graded distributions. Here, we describe an experimental test of this model for Wingless, one of the key organizers of wing development in Drosophila. Maximal Wingless signaling suppresses cellular proliferation. In contrast, we found that moderate and uniform amounts of exogenous Wingless, even in the absence of endogenous Wingless, stimulated proliferative growth. Beyond a few cell diameters from the source, Wingless was relatively constant in abundance and thus provided a homogeneous growth-promoting signal. Although morphogen signaling may act in combination with as yet uncharacterized graded growth-promoting pathways, we suggest that the graded nature of morphogen signaling is not required for proliferation, at least in the developing Drosophila wing, during the main period of growth.
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Affiliation(s)
- Luis Alberto Baena-Lopez
- Department of Developmental Neurobiology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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195
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Nahmad M, Stathopoulos A. Dynamic interpretation of hedgehog signaling in the Drosophila wing disc. PLoS Biol 2009; 7:e1000202. [PMID: 19787036 PMCID: PMC2744877 DOI: 10.1371/journal.pbio.1000202] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 08/13/2009] [Indexed: 11/19/2022] Open
Abstract
Morphogens are classically defined as molecules that control patterning by acting at a distance to regulate gene expression in a concentration-dependent manner. In the Drosophila wing imaginal disc, secreted Hedgehog (Hh) forms an extracellular gradient that organizes patterning along the anterior-posterior axis and specifies at least three different domains of gene expression. Although the prevailing view is that Hh functions in the Drosophila wing disc as a classical morphogen, a direct correspondence between the borders of these patterns and Hh concentration thresholds has not been demonstrated. Here, we provide evidence that the interpretation of Hh signaling depends on the history of exposure to Hh and propose that a single concentration threshold is sufficient to support multiple outputs. Using mathematical modeling, we predict that at steady state, only two domains can be defined in response to Hh, suggesting that the boundaries of two or more gene expression patterns cannot be specified by a static Hh gradient. Computer simulations suggest that a spatial "overshoot" of the Hh gradient occurs, i.e., a transient state in which the Hh profile is expanded compared to the Hh steady-state gradient. Through a temporal examination of Hh target gene expression, we observe that the patterns initially expand anteriorly and then refine, providing in vivo evidence for the overshoot. The Hh gene network architecture suggests this overshoot results from the Hh-dependent up-regulation of the receptor, Patched (Ptc). In fact, when the network structure was altered such that the ptc gene is no longer up-regulated in response to Hh-signaling activation, we found that the patterns of gene expression, which have distinct borders in wild-type discs, now overlap. Our results support a model in which Hh gradient dynamics, resulting from Ptc up-regulation, play an instructional role in the establishment of patterns of gene expression.
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Affiliation(s)
- Marcos Nahmad
- Department of Control and Dynamical Systems, California Institute of Technology, Pasadena, California, United States of America
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Angelike Stathopoulos
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- * E-mail:
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196
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Yu SR, Burkhardt M, Nowak M, Ries J, Petrásek Z, Scholpp S, Schwille P, Brand M. Fgf8 morphogen gradient forms by a source-sink mechanism with freely diffusing molecules. Nature 2009; 461:533-6. [PMID: 19741606 DOI: 10.1038/nature08391] [Citation(s) in RCA: 276] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 08/07/2009] [Indexed: 01/13/2023]
Abstract
It is widely accepted that tissue differentiation and morphogenesis in multicellular organisms are regulated by tightly controlled concentration gradients of morphogens. How exactly these gradients are formed, however, remains unclear. Here we show that Fgf8 morphogen gradients in living zebrafish embryos are established and maintained by two essential factors: fast, free diffusion of single molecules away from the source through extracellular space, and a sink function of the receiving cells, regulated by receptor-mediated endocytosis. Evidence is provided by directly examining single molecules of Fgf8 in living tissue by fluorescence correlation spectroscopy, quantifying their local mobility and concentration with high precision. By changing the degree of uptake of Fgf8 into its target cells, we are able to alter the shape of the Fgf8 gradient. Our results demonstrate that a freely diffusing morphogen can set up concentration gradients in a complex multicellular tissue by a simple source-sink mechanism.
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Affiliation(s)
- Shuizi Rachel Yu
- Developmental Genetics, Biotechnology Center, TUD, Tatzberg 47-49, 01307 Dresden, Germany
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197
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Baker RE, Schnell S, Maini PK. Waves and patterning in developmental biology: vertebrate segmentation and feather bud formation as case studies. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2009; 53:783-94. [PMID: 19557684 DOI: 10.1387/ijdb.072493rb] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In this article we will discuss the integration of developmental patterning mechanisms with waves of competency that control the ability of a homogeneous field of cells to react to pattern forming cues and generate spatially heterogeneous patterns. We base our discussion around two well known patterning events that take place in the early embryo: somitogenesis and feather bud formation. We outline mathematical models to describe each patterning mechanism, present the results of numerical simulations and discuss the validity of each model in relation to our example patterning processes.
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Affiliation(s)
- Ruth E Baker
- Centre for Mathematical Biology, University of Oxford, UK.
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198
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Oates AC, Gorfinkiel N, González-Gaitán M, Heisenberg CP. Quantitative approaches in developmental biology. Nat Rev Genet 2009; 10:517-30. [DOI: 10.1038/nrg2548] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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199
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Temporal dynamics of patterning by morphogen gradients. Curr Opin Genet Dev 2009; 19:315-22. [DOI: 10.1016/j.gde.2009.05.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Accepted: 05/18/2009] [Indexed: 12/21/2022]
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200
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Côte P, Hogues H, Whiteway M. Transcriptional analysis of the Candida albicans cell cycle. Mol Biol Cell 2009; 20:3363-73. [PMID: 19477921 DOI: 10.1091/mbc.e09-03-0210] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We have examined the periodic expression of genes through the cell cycle in cultures of the human pathogenic fungus Candida albicans synchronized by mating pheromone treatment. Close to 500 genes show increased expression during the G1, S, G2, or M transitions of the C. albicans cell cycle. Comparisons of these C. albicans periodic genes with those already found in the budding and fission yeasts and in human cells reveal that of 2200 groups of homologous genes, close to 600 show periodicity in at least one organism, but only 11 are periodic in all four species. Overall, the C. albicans regulatory circuit most closely resembles that of Saccharomyces cerevisiae but contains a simplified structure. Although the majority of the C. albicans periodically regulated genes have homologues in the budding yeast, 20% (100 genes), most of which peak during the G1/S or M/G1 transitions, are unique to the pathogenic yeast.
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Affiliation(s)
- Pierre Côte
- Genetics Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Québec H4P 2R2, Canada
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