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Atajanova T, Kang EM, Postnikova A, Price AL, Doerr S, Du M, Ugenti A, Ragkousi K. Lateral cell polarization drives organization of epithelia in sea anemone embryos and embryonic cell aggregates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.07.588493. [PMID: 38645007 PMCID: PMC11030385 DOI: 10.1101/2024.04.07.588493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
One of the first organizing processes during animal development is the assembly of embryonic cells into epithelia. In certain animals, including Hydra and sea anemones, epithelia also emerge when cells from dissociated tissues are aggregated back together. Although cell adhesion is required to keep cells together, it is not clear whether cell polarization plays a role as epithelia emerge from disordered aggregates. Here, we demonstrate that lateral cell polarization is essential for epithelial organization in both embryos and aggregates of the sea anemone Nematostella vectensis. Specifically, knock down of the lateral polarity protein Lgl disrupts epithelia in developing embryos and impairs the capacity of dissociated cells to epithelialize from aggregates. Cells in lgl mutant epithelia lose their columnar shape and have mispositioned mitotic spindles and ciliary basal bodies. Together, our data suggest that in Nematostella, Lgl is required to establish lateral cell polarity and position cytoskeletal organelles in cells of embryos and aggregates during de novo epithelial organization.
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Affiliation(s)
- Tavus Atajanova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | | | - Anna Postnikova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | | | - Sophia Doerr
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Michael Du
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Alicia Ugenti
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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2
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Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR protein caps orient the mitotic spindle in C. elegans early embryos. Curr Biol 2023; 33:4312-4329.e6. [PMID: 37729910 PMCID: PMC10615879 DOI: 10.1016/j.cub.2023.08.069] [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: 03/27/2023] [Revised: 07/24/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases, it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact-free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, isolated single blastomeres lacking cell contacts are able to break symmetry and form PAR-3/atypical protein kinase C (aPKC) caps. Polarity caps form independently of actomyosin flows and microtubules and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
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Affiliation(s)
- Naomi J Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Nadia I Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Daniel J Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA.
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3
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Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR-3 caps orient the mitotic spindle in C. elegans early embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.27.534341. [PMID: 37034756 PMCID: PMC10081169 DOI: 10.1101/2023.03.27.534341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, apical PAR-3 can form polarity caps independently of actomyosin flows and the small GTPase CDC-42, and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
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Affiliation(s)
- Naomi J. Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Nadia I. Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Daniel J. Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
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4
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Jonusaite S, Oulhen N, Izumi Y, Furuse M, Yamamoto T, Sakamoto N, Wessel G, Heyland A. Identification of the genes encoding candidate septate junction components expressed during early development of the sea urchin, Strongylocentrotus purpuratus, and evidence of a role for Mesh in the formation of the gut barrier. Dev Biol 2023; 495:21-34. [PMID: 36587799 DOI: 10.1016/j.ydbio.2022.12.007] [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: 07/07/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022]
Abstract
Septate junctions (SJs) evolved as cell-cell junctions that regulate the paracellular barrier and integrity of epithelia in invertebrates. Multiple morphological variants of SJs exist specific to different epithelia and/or phyla but the biological significance of varied SJ morphology is unclear because the knowledge of the SJ associated proteins and their functions in non-insect invertebrates remains largely unknown. Here we report cell-specific expression of nine candidate SJ genes in the early life stages of the sea urchin Strongylocentrotus purpuratus. By use of in situ RNA hybridization and single cell RNA-seq we found that the expression of selected genes encoding putatively SJ associated transmembrane and cytoplasmic scaffold molecules was dynamically regulated during epithelial development in the embryos and larvae with different epithelia expressing different cohorts of SJ genes. We focused a functional analysis on SpMesh, a homolog of the Drosophila smooth SJ component Mesh, which was highly enriched in the endodermal epithelium of the mid- and hindgut. Functional perturbation of SpMesh by both CRISPR/Cas9 mutagenesis and vivo morpholino-mediated knockdown shows that loss of SpMesh does not disrupt the formation of the gut epithelium during gastrulation. However, loss of SpMesh resulted in a severely reduced gut-paracellular barrier as quantitated by increased permeability to 3-5 kDa FITC-dextran. Together, these studies provide a first look at the molecular SJ physiology during the development of a marine organism and suggest a shared role for Mesh-homologous proteins in forming an intestinal barrier in invertebrates. Results have implications for consideration of the traits underlying species-specific sensitivity of marine larvae to climate driven ocean change.
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Affiliation(s)
- Sima Jonusaite
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, United States
| | - Yasushi Izumi
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan; Nagoya University Graduate School of Medicine, Aichi, 464-8601, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Naoaki Sakamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Gary Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, United States
| | - Andreas Heyland
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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5
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Wright BA, Kvansakul M, Schierwater B, Humbert PO. Cell polarity signalling at the birth of multicellularity: What can we learn from the first animals. Front Cell Dev Biol 2022; 10:1024489. [PMID: 36506100 PMCID: PMC9729800 DOI: 10.3389/fcell.2022.1024489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 10/31/2022] [Indexed: 11/25/2022] Open
Abstract
The innovation of multicellularity has driven the unparalleled evolution of animals (Metazoa). But how is a multicellular organism formed and how is its architecture maintained faithfully? The defining properties and rules required for the establishment of the architecture of multicellular organisms include the development of adhesive cell interactions, orientation of division axis, and the ability to reposition daughter cells over long distances. Central to all these properties is the ability to generate asymmetry (polarity), coordinated by a highly conserved set of proteins known as cell polarity regulators. The cell polarity complexes, Scribble, Par and Crumbs, are considered to be a metazoan innovation with apicobasal polarity and adherens junctions both believed to be present in all animals. A better understanding of the fundamental mechanisms regulating cell polarity and tissue architecture should provide key insights into the development and regeneration of all animals including humans. Here we review what is currently known about cell polarity and its control in the most basal metazoans, and how these first examples of multicellular life can inform us about the core mechanisms of tissue organisation and repair, and ultimately diseases of tissue organisation, such as cancer.
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Affiliation(s)
- Bree A. Wright
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, VIC, Australia
| | - Bernd Schierwater
- Institute of Animal Ecology and Evolution, University of Veterinary Medicine Hannover, Foundation, Bünteweg, Hannover, Germany
| | - Patrick O. Humbert
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, VIC, Australia,Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia,Department of Clinical Pathology, University of Melbourne, Melbourne, VIC, Australia,*Correspondence: Patrick O. Humbert,
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6
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Rathbun LI, Everett CA, Bergstralh DT. Emerging Cnidarian Models for the Study of Epithelial Polarity. Front Cell Dev Biol 2022; 10:854373. [PMID: 35433674 PMCID: PMC9012326 DOI: 10.3389/fcell.2022.854373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Epithelial tissues are vital to the function of most organs, providing critical functions such as secretion, protection, and absorption. Cells within an epithelial layer must coordinate to create functionally distinct apical, lateral, and basal surfaces in order to maintain proper organ function and organism viability. This is accomplished through the careful targeting of polarity factors to their respective locations within the cell, as well as the strategic placement of post-mitotic cells within the epithelium during tissue morphogenesis. The process of establishing and maintaining epithelial tissue integrity is conserved across many species, as important polarity factors and spindle orientation mechanisms can be found in many phyla. However, most of the information gathered about these processes and players has been investigated in bilaterian organisms such as C. elegans, Drosophila, and vertebrate species. This review discusses the advances made in the field of epithelial polarity establishment from more basal organisms, and the advantages to utilizing these simpler models. An increasing number of cnidarian model organisms have been sequenced in recent years, such as Hydra vulgaris and Nematostella vectensis. It is now feasible to investigate how polarity is established and maintained in basal organisms to gain an understanding of the most basal requirements for epithelial tissue morphogenesis.
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7
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Martindale MQ. Emerging models: The "development" of the ctenophore Mnemiopsis leidyi and the cnidarian Nematostella vectensis as useful experimental models. Curr Top Dev Biol 2022; 147:93-120. [PMID: 35337468 DOI: 10.1016/bs.ctdb.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The goal of this chapter is to explain the reasoning for developing two understudied invertebrate animal species for asking specific biological questions. The first is the ctenophore (comb jelly) Mnemiopsis leidyi and the second is the anthozoan cnidarian (starlet sea anemone) Nematostella vectensis. Although these two taxa belong to some of the earliest branching extant metazoan clades, their developmental features could hardly be more different from one another. This should serve as a general warning to be careful when extrapolating comparisons of one species to another. Two-taxon comparisons are especially flawed; and to interpret features in a phylogenetic context one must sample carefully within a given taxon to determine how representative certain features are before comparing with other clades. The other benefit of this comparison is to identify key practical factors when attempting to develop new species for experimental investigation.
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Affiliation(s)
- Mark Q Martindale
- Whitney Lab for Marine Bioscience, University of Florida, St. Augustine, FL, United States.
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8
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Wijesena N, Sun H, Kumburegama S, Wikramanayake AH. Distinct Frizzled receptors independently mediate endomesoderm specification and primary archenteron invagination during gastrulation in Nematostella. Dev Biol 2021; 481:215-225. [PMID: 34767794 DOI: 10.1016/j.ydbio.2021.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 11/03/2022]
Abstract
Endomesodermal cell fate specification and archenteron formation during gastrulation are tightly linked developmental processes in most metazoans. However, studies have shown that in the anthozoan cnidarian Nematostella vectensis, Wnt/β-catenin (cWnt) signalling-mediated endomesodermal cell fate specification can be experimentally uncoupled from Wnt/Planar Cell Polarity (PCP) signalling-mediated primary archenteron invagination. The upstream signalling mechanisms regulating cWnt signalling-dependent endomesoderm cell fate specification and Wnt/PCP signalling-mediated primary archenteron invagination in Nematostella embryos are not well understood. By screening for potential upstream mediators of cWnt and Wnt/PCP signalling, we identified two Nematostella Frizzled homologs that are expressed early in development. NvFzd1 is expressed maternally and in a broad pattern during early development while NvFzd10 is zygotically expressed at the animal pole in blastula stage embryos and is restricted to the invaginating cells of the presumptive endomesoderm. Molecular and morphological characterization of NvFzd1 and NvFzd10 knock-down phenotypes provide evidence for distinct regulatory roles for the two receptors in endomesoderm cell fate specification and primary archenteron invagination. These results provide further experimental evidence for the independent regulation of endomesodermal cell fate specification and primary archenteron invagination during gastrulation in Nematostella. Moreover, these results provide additional support for the previously proposed two-step model for the independent evolution of cWnt-mediated cell fate specification and Wnt/PCP-mediated primary archenteron invagination.
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Affiliation(s)
- Naveen Wijesena
- Department of Biology, University of Miami, Coral Gables, FL33146, USA; Department of Biology, University of Bergen, Bergen, Norway
| | - Hongyan Sun
- Department of Biology, University of Miami, Coral Gables, FL33146, USA
| | - Shalika Kumburegama
- Department of Biology, University of Miami, Coral Gables, FL33146, USA; Department of Zoology, University of Peradeniya, Peradeniya, Sri Lanka
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9
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Mashukova A, Forteza R, Shah VN, Salas PJ. The cell polarity kinase Par1b/MARK2 activation selects specific NF-kB transcripts via phosphorylation of core mediator Med17/TRAP80. Mol Biol Cell 2021; 32:690-702. [PMID: 33596087 PMCID: PMC8108508 DOI: 10.1091/mbc.e20-10-0646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Par1b/MARK2 is a Ser/Thr kinase with pleiotropic effects that participates in the generation of apico-basal polarity in Caenorhabditis elegans. It is phosphorylated by atypical PKC(ι/λ) in Thr595 and inhibited. Because previous work showed a decrease in atypical protein kinase C (aPKC) activity under proinflammatory conditions, we analyzed the hypothesis that the resulting decrease in Thr595-MARK2 with increased kinase activity may also participate in innate immunity. We confirmed that pT595-MARK2 was decreased under inflammatory stimulation. The increase in MARK2 activity was verified by Par3 delocalization and rescue with a specific inhibitor. MARK2 overexpression significantly enhanced the transcriptional activity of NF-kB for a subset of transcripts. It also resulted in phosphorylation of a single band (∼Mr 80,000) coimmunoprecipitating with RelA, identified as Med17. In vitro phosphorylation showed direct phosphorylation of Med17 in Ser152 by recombinant MARK2. Expression of S152D-Med17 mimicked the effect of MARK2 activation on downstream transcriptional regulation, which was antagonized by S152A-Med17. The decrease in pThr595 phosphorylation was validated in aPKC-deficient mouse jejunal mucosae. The transcriptional effects were confirmed in transcriptome analysis and transcript enrichment determinations in cells expressing S152D-Med17. We conclude that theMARK2-Med17 axis represents a novel form of cross-talk between polarity signaling and transcriptional regulation including, but not restricted to, innate immunity responses.
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Affiliation(s)
- Anastasia Mashukova
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136.,Department of Medical Education, Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314
| | - Radia Forteza
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
| | - Viraj N Shah
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
| | - Pedro J Salas
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
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10
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Salinas-Saavedra M, Martindale MQ. Par protein localization during the early development of Mnemiopsis leidyi suggests different modes of epithelial organization in the metazoa. eLife 2020; 9:54927. [PMID: 32716297 PMCID: PMC7441587 DOI: 10.7554/elife.54927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/23/2020] [Indexed: 02/07/2023] Open
Abstract
In bilaterians and cnidarians, epithelial cell-polarity is regulated by the interactions between Par proteins, Wnt/PCP signaling pathway, and cell-cell adhesion. Par proteins are highly conserved across Metazoa, including ctenophores. But strikingly, ctenophore genomes lack components of the Wnt/PCP pathway and cell-cell adhesion complexes raising the question if ctenophore cells are polarized by mechanisms involving Par proteins. Here, by using immunohistochemistry and live-cell imaging of specific mRNAs, we describe for the first time the subcellular localization of selected Par proteins in blastomeres and epithelial cells during the embryogenesis of the ctenophore Mnemiopsis leidyi. We show that these proteins distribute differently compared to what has been described for other animals, even though they segregate in a host-specific fashion when expressed in cnidarian embryos. This differential localization might be related to the emergence of different junctional complexes during metazoan evolution.
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Affiliation(s)
- Miguel Salinas-Saavedra
- The Whitney Laboratory for Marine Bioscience, and the Department of Biology, University of Florida, St. Augustine, United States
| | - Mark Q Martindale
- The Whitney Laboratory for Marine Bioscience, and the Department of Biology, University of Florida, St. Augustine, United States
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11
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Technau U. Gastrulation and germ layer formation in the sea anemone Nematostella vectensis and other cnidarians. Mech Dev 2020; 163:103628. [PMID: 32603823 DOI: 10.1016/j.mod.2020.103628] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/23/2020] [Accepted: 06/19/2020] [Indexed: 01/03/2023]
Abstract
Among the basally branching metazoans, cnidarians display well-defined gastrulation processes leading to a diploblastic body plan, consisting of an endodermal and an ectodermal cell layer. As the outgroup to all Bilateria, cnidarians are an interesting group to investigate ancestral developmental mechanisms. Interestingly, all known gastrulation mechanisms known in Bilateria are already found in different species of Cnidaria. Here I review the morphogenetic processes found in different Cnidaria and focus on the investigation of the cellular and molecular mechanisms in the sea anemone Nematostella vectensis, which has been a major model organism among cnidarians for evolutionary developmental biology. Many of the genes involved in germ layer specification and morphogenetic processes in Bilateria are also found active during gastrulation of Nematostella and other cnidarians, suggesting an ancestral role of this process. The molecular analyses indicate a tight link between gastrulation and axis patterning processes by Wnt and FGF signaling. Interestingly, the endodermal layer displays many features of the mesodermal layer in Bilateria, while the pharyngeal ectoderm has an endodermal expression profile. Comparative analyses as well as experimental studies using embryonic aggregates suggest that minor differences in the gene regulatory networks allow the embryo to transition relatively easily from one mode of gastrulation to another.
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Affiliation(s)
- Ulrich Technau
- University of Vienna, Dept. of Neurosciences and Developmental Biology, Althanstrasse 14, 1090 Wien, Austria.
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12
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Salinas-Saavedra M, Rock AQ, Martindale MQ. Germ layer-specific regulation of cell polarity and adhesion gives insight into the evolution of mesoderm. eLife 2018; 7:e36740. [PMID: 30063005 PMCID: PMC6067901 DOI: 10.7554/elife.36740] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/29/2018] [Indexed: 12/20/2022] Open
Abstract
In triploblastic animals, Par-proteins regulate cell-polarity and adherens junctions of both ectodermal and endodermal epithelia. But, in embryos of the diploblastic cnidarian Nematostella vectensis, Par-proteins are degraded in all cells in the bifunctional gastrodermal epithelium. Using immunohistochemistry, CRISPR/Cas9 mutagenesis, and mRNA overexpression, we describe the functional association between Par-proteins, ß-catenin, and snail transcription factor genes in N. vectensis embryos. We demonstrate that the aPKC/Par complex regulates the localization of ß-catenin in the ectoderm by stabilizing its role in cell-adhesion, and that endomesodermal epithelial cells are organized by a different cell-adhesion system than overlying ectoderm. We also show that ectopic expression of snail genes, which are expressed in mesodermal derivatives in bilaterians, is sufficient to downregulate Par-proteins and translocate ß-catenin from the junctions to the cytoplasm in ectodermal cells. These data provide molecular insight into the evolution of epithelial structure and distinct cell behaviors in metazoan embryos.
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Affiliation(s)
- Miguel Salinas-Saavedra
- The Whitney
Laboratory for Marine BioscienceUniversity of
FloridaFloridaUnited
States
- Department of
BiologyUniversity of
FloridaFloridaUnited
States
| | - Amber Q Rock
- The Whitney
Laboratory for Marine BioscienceUniversity of
FloridaFloridaUnited
States
| | - Mark Q Martindale
- The Whitney
Laboratory for Marine BioscienceUniversity of
FloridaFloridaUnited
States
- Department of
BiologyUniversity of
FloridaFloridaUnited
States
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13
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Nakama AB, Chou HC, Schneider SQ. The asymmetric cell division machinery in the spiral-cleaving egg and embryo of the marine annelid Platynereis dumerilii. BMC DEVELOPMENTAL BIOLOGY 2017; 17:16. [PMID: 29228898 PMCID: PMC5725810 DOI: 10.1186/s12861-017-0158-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/23/2017] [Indexed: 12/29/2022]
Abstract
BACKGROUND Over one third of all animal phyla utilize a mode of early embryogenesis called 'spiral cleavage' to divide the fertilized egg into embryonic cells with different cell fates. This mode is characterized by a series of invariant, stereotypic, asymmetric cell divisions (ACDs) that generates cells of different size and defined position within the early embryo. Astonishingly, very little is known about the underlying molecular machinery to orchestrate these ACDs in spiral-cleaving embryos. Here we identify, for the first time, cohorts of factors that may contribute to early embryonic ACDs in a spiralian embryo. RESULTS To do so we analyzed stage-specific transcriptome data in eggs and early embryos of the spiralian annelid Platynereis dumerilii for the expression of over 50 candidate genes that are involved in (1) establishing cortical domains such as the partitioning defective (par) genes, (2) directing spindle orientation, (3) conveying polarity cues including crumbs and scribble, and (4) maintaining cell-cell adhesion between embryonic cells. In general, each of these cohorts of genes are co-expressed exhibiting high levels of transcripts in the oocyte and fertilized single-celled embryo, with progressively lower levels at later stages. Interestingly, a small number of key factors within each ACD module show different expression profiles with increased early zygotic expression suggesting distinct regulatory functions. In addition, our analysis discovered several highly co-expressed genes that have been associated with specialized neural cell-cell recognition functions in the nervous system. The high maternal contribution of these 'neural' adhesion complexes indicates novel general adhesion functions during early embryogenesis. CONCLUSIONS Spiralian embryos are champions of ACD generating embryonic cells of different size with astonishing accuracy. Our results suggest that the molecular machinery for ACD is already stored as maternal transcripts in the oocyte. Thus, the spiralian egg can be viewed as a totipotent yet highly specialized cell that evolved to execute fast and precise ACDs during spiral cleaving stages. Our survey identifies cohorts of factors in P. dumerilii that are candidates for these molecular mechanisms and their regulation, and sets the stage for a functional dissection of ACD in a spiral-cleaving embryo.
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Affiliation(s)
- Aron B. Nakama
- Department of Genetics, Development and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
| | - Hsien-Chao Chou
- Department of Genetics, Development and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
- current address: Center for Cancer Research, National Institutes of Health, Bethesda, MD 20894 USA
| | - Stephan Q. Schneider
- Department of Genetics, Development and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
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Servetnick MD, Steinworth B, Babonis LS, Simmons D, Salinas-Saavedra M, Martindale MQ. Cas9-mediated excision of Nematostella brachyury disrupts endoderm development, pharynx formation and oral-aboral patterning. Development 2017; 144:2951-2960. [PMID: 28705897 PMCID: PMC5592810 DOI: 10.1242/dev.145839] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 07/05/2017] [Indexed: 12/26/2022]
Abstract
The mesoderm is a key novelty in animal evolution, although we understand little of how the mesoderm arose. brachyury, the founding member of the T-box gene family, is a key gene in chordate mesoderm development. However, the brachyury gene was present in the common ancestor of fungi and animals long before mesoderm appeared. To explore ancestral roles of brachyury prior to the evolution of definitive mesoderm, we excised the gene using CRISPR/Cas9 in the diploblastic cnidarian Nematostella vectensis Nvbrachyury is normally expressed in precursors of the pharynx, which separates endoderm from ectoderm. In knockout embryos, the pharynx does not form, embryos fail to elongate, and endoderm organization, ectodermal cell polarity and patterning along the oral-aboral axis are disrupted. Expression of many genes both inside and outside the Nvbrachyury expression domain is affected, including downregulation of Wnt genes at the oral pole. Our results point to an ancient role for brachyury in morphogenesis, cell polarity and the patterning of both ectodermal and endodermal derivatives along the primary body axis.
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Affiliation(s)
- Marc D Servetnick
- Division of Biological Sciences, University of Washington Bothell, Bothell, WA 98011, USA
| | - Bailey Steinworth
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
| | - Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
| | - David Simmons
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
| | - Miguel Salinas-Saavedra
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
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Cell-Cycle-Coupled Oscillations in Apical Polarity and Intercellular Contact Maintain Order in Embryonic Epithelia. Curr Biol 2017; 27:1381-1386. [DOI: 10.1016/j.cub.2017.03.064] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/18/2017] [Accepted: 03/27/2017] [Indexed: 11/22/2022]
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Salas PJ, Forteza R, Mashukova A. Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity. Tissue Barriers 2016; 4:e1178368. [PMID: 27583190 PMCID: PMC4993576 DOI: 10.1080/21688370.2016.1178368] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/27/2022] Open
Abstract
As multicellular organisms evolved a family of cytoskeletal proteins, the keratins (types I and II) expressed in epithelial cells diversified in more than 20 genes in vertebrates. There is no question that keratin filaments confer mechanical stiffness to cells. However, such a number of genes can hardly be explained by evolutionary advantages in mechanical features. The use of transgenic mouse models has revealed unexpected functional relationships between keratin intermediate filaments and intracellular signaling. Accordingly, loss of keratins or mutations in keratins that cause or predispose to human diseases, result in increased sensitivity to apoptosis, regulation of innate immunity, permeabilization of tight junctions, and mistargeting of apical proteins in different epithelia. Precise mechanistic explanations for these phenomena are still lacking. However, immobilization of membrane or cytoplasmic proteins, including chaperones, on intermediate filaments (“scaffolding”) appear as common molecular mechanisms and may explain the need for so many different keratin genes in vertebrates.
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Affiliation(s)
- Pedro J Salas
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Radia Forteza
- Department of Cell Biology, Miller School of Medicine, University of Miami , Miami, FL, USA
| | - Anastasia Mashukova
- Department of Cell Biology, Miller School of Medicine, University of Miami, Miami, FL, USA; Department of Physiology, Nova Southeastern University, Fort Lauderdale, FL, USA
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17
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Sequential development of apical-basal and planar polarities in aggregating epitheliomuscular cells of Hydra. Dev Biol 2016; 412:148-159. [DOI: 10.1016/j.ydbio.2016.02.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/18/2016] [Accepted: 02/23/2016] [Indexed: 11/24/2022]
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18
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Levitan S, Sher N, Brekhman V, Ziv T, Lubzens E, Lotan T. The making of an embryo in a basal metazoan: Proteomic analysis in the sea anemoneNematostella vectensis. Proteomics 2015; 15:4096-104. [DOI: 10.1002/pmic.201500255] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 07/25/2015] [Accepted: 09/09/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Shimrit Levitan
- Marine Biology Department, The Leon H. Charney School of Marine Sciences; University of Haifa; Haifa Israel
| | - Noa Sher
- Bioinformatics Service Unit; University of Haifa; Haifa Israel
| | - Vera Brekhman
- Marine Biology Department, The Leon H. Charney School of Marine Sciences; University of Haifa; Haifa Israel
| | - Tamar Ziv
- Faculty of Biology; Technion - Israel Institute of Technology; Haifa Israel
| | - Esther Lubzens
- Faculty of Biology; Technion - Israel Institute of Technology; Haifa Israel
| | - Tamar Lotan
- Marine Biology Department, The Leon H. Charney School of Marine Sciences; University of Haifa; Haifa Israel
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