Dynamics of Thin Filopodia During Sea Urchin Gastrulation
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Divergence of Ectodermal and Mesodermal Gene Regulatory Network Linkages in Early Development of Sea Urchins
Divergence of ectodermal and mesodermal gene regulatory network linkages in early development of sea urchins Eric M. Erkenbracka,1,2 aDivision of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 Edited by Neil H. Shubin, The University of Chicago, Chicago, IL, and approved October 5, 2016 (received for review August 3, 2016) Developmental gene regulatory networks (GRNs) are assemblages of to study in sea urchins, whose lineages have undergone multiple gene regulatory interactions that direct ontogeny of animal body changes in life history strategies (8). Importantly, an excellent fossil plans. Studies of GRNs operating in the early development of record affords dating of evolutionary events (9), which has established euechinoid sea urchins have revealed that little appreciable change has that the sister subclasses of sea urchins—cidaroids and euechinoids— occurred since their divergence ∼90 million years ago (mya). These diverged at least 268 million years ago (mya) (10). Differences in observations suggest that strong conservation of GRN architecture the timing of developmental events in embryogenesis of cida- was maintained in early development of the sea urchin lineage. Test- roids and euechinoids have long been a topic of interest, but ing whether this holds for all sea urchins necessitates comparative have become the subject of molecular research only recently analyses of echinoid taxa that diverged deeper in geological time. (11–18). Recent studies highlighted extensive divergence of skeletogenic me- Research on the early development of the euechinoid purple soderm specification in the sister clade of euechinoids, the cidaroids, sea urchin Strongylocentrotus purpuratus (Sp) has brought into suggesting that comparative analyses of cidaroid GRN architecture high resolution the players and molecular logic directing devel- may confer a greater understanding of the evolutionary dynamics of opmental GRNs that specify Sp’s early embryonic domains developmental GRNs. -
Animal Form & Function
Animals Animal Form & Function By far, most diversity of bauplane (body forms). And most variations within bauplane. Animals are Animated “ANIMAL” ≠ MAMMAL — Fascinating Behaviors Animal Cells • Eukaryotic • No cell wall No plastids No central vacuole • Multicellular: – extensive specialization & differentiation – unique cell-cell junctions Heyer 1 Animals Animals Blastulation & Gastrulation • Motile • Early embryonic development in animals 3 In most animals, cleavage results in the formation of a multicellular stage called a 1 The zygote of an animal • Highly differentiated blastula. The blastula of many animals is a undergoes a succession of mitotic tissues cell divisions called cleavage. hollow ball of cells. Blastocoel • Intercellular junctions Cleavage Cleavage – tissue-specific cadherins 6 The endoderm of the archenteron develops into Eight-cell stage Blastula Cross section Zygote • Extracellular protein the the animal’s of blastula fibers digestive tract. Blastocoel Endoderm – collagen 5 The blind pouch formed by gastrulation, called Ectoderm • Diploid life cycle the archenteron, opens to the outside Gastrula Gastrulation via the blastopore. Blastopore 4 Most animals also undergo gastrulation, a • Blastula/gastrula rearrangement of the embryo in which one end of the embryo folds inward, expands, and eventually fills the embryo blastocoel, producing layers of embryonic tissues: the Figure 32.2 ectoderm (outer layer) and the endoderm (inner layer). Primary embryonic germ layers Primary embryonic germ layers • Diploblastic: two germ -
T-Brain Regulates Archenteron Induction Signal 5207 Range of Amplification
Development 129, 5205-5216 (2002) 5205 Printed in Great Britain © The Company of Biologists Limited 2002 DEV5034 T-brain homologue (HpTb) is involved in the archenteron induction signals of micromere descendant cells in the sea urchin embryo Takuya Fuchikami1, Keiko Mitsunaga-Nakatsubo1, Shonan Amemiya2, Toshiya Hosomi1, Takashi Watanabe1, Daisuke Kurokawa1,*, Miho Kataoka1, Yoshito Harada3, Nori Satoh3, Shinichiro Kusunoki4, Kazuko Takata1, Taishin Shimotori1, Takashi Yamamoto1, Naoaki Sakamoto1, Hiraku Shimada1 and Koji Akasaka1,† 1Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan 2Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 3Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan 4LSL, Nerima-ku, Tokyo 178-0061, Japan *Present address: Evolutionary Regeneration Biology Group, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan †Author for correspondence (e-mail: [email protected]) Accepted 30 July 2002 SUMMARY Signals from micromere descendants play a crucial role in cells, the initial specification of primary mesenchyme cells, sea urchin development. In this study, we demonstrate that or the specification of endoderm. HpTb expression is these micromere descendants express HpTb, a T-brain controlled by nuclear localization of β-catenin, suggesting homolog of Hemicentrotus pulcherrimus. HpTb is expressed that -
Apoptosis in Amphibian Development
Advances in Bioscience and Biotechnology, 2012, 3, 669-678 ABB http://dx.doi.org/10.4236/abb.2012.326087 Published Online October 2012 (http://www.SciRP.org/journal/abb/) Apoptosis in amphibian development Jean-Marie Exbrayat, Elara N. Moudilou, Lucie Abrouk, Claire Brun Université de Lyon, UMRS 449, Biologie Générale, Université Catholique de Lyon, Reproduction et Développement Comparé, Ecole Pratique des Hautes Etudes, Lyon, France Email: [email protected] Received 13 August 2012; revised 20 September 2012; accepted 28 September 2012 ABSTRACT divide to give the first two blastomeres which continue to divide becoming a morula. An inner cavity, the blasto- Amphibians and more particularly X. laevis are mod- coel, appears in the mass cell of the embryo, becoming a els often used for studying apoptosis during embry- blastula. During this period of cleavage, the size and onic development. Using several methods, searchers shape of embryos do not vary. Before mid blastula tran- determined the localization of programmed cell sition (MBT), zygotic genes do not express excepted deaths (PCD). Several experimental methods also those encoding for proteins implicated in membrane have been used to understand the regulatory mecha- building. Maternal mRNAs previously accumulated in nisms of apoptosis, throughout development, contrib- the oocytes remain present in the cytoplasm of zygote uting to elucidate the general action of several genes and they are distributed into the cytoplasm of blas- and proteins. Apoptosis occurs very early, with a first tomeres during cleavage. These maternal mRNAs encode program under control of maternal genes expressed for proteins which will be implicated in expression of before MBT, in order to eliminate damaged cells be- zygotic genes. -
4 Mechanics of the Cytoskeleton
4 Mechanics of the cytoskeleton 4.1 Motivation In the previous section, we have seen how biopolymers dynamically assemble and dis- assemble during polymerization. We have discussed the individual mechanical prop- erties such as Young’s modulus E, the axial stiffness EA, the bending stiffness EI, and the persistence length A for individual filaments. In particular, have talked about actin filaments, intermediate filaments, and microtubules. Now, assuming we know the me- chanical properties of the individual filaments, what does that actually tell us about the assembly of filaments that we find in the cell? Or, to put it differently, if we knew elements of the cytoskeleton microtubules intermediate filaments actin filaments Figure 4.1: The cytoskeleton provides structural stability and is responsible for forces during cell loco- motion. Microtubules are thick hollow cylinders reaching out from the nucleus to the membrane, inter- mediate filaments can be found anywhere in the cytosol, and actin filaments are usually concentrated close to the cell membrane. the structural arrangement of filaments, could we then predict the stiffness of the over- all assembly? How does the filament microstructure affect cytoskeletal properties? Or, more precisely, how can we calculate the macroscopic network properties from the in- dividual microscopic filament properties? In mechanics, the derivation of macroscopic parameters based on microscopic considerations is referred to as homogenization. In this chapter, we illustrate the homogenization by means of three different examples, the fiber bundle model for filopodia, the network model for red blood cell membranes, and the tensegrity model for generic cell structures. 4.2 Fiber bundle model for filopodia Filopodia are thin dynamic cytoplasmic projections composed of tight bundles of long actin filaments extending from the leading edge of migrating cells. -
Of Polarity Ups and Downs of Guided Vessel Sprouting
Ups and Downs of Guided Vessel Sprouting: The Role of Polarity Christina Y. Lee and Victoria L. Bautch Physiology 26:326-333, 2011. doi:10.1152/physiol.00018.2011 You might find this additional info useful... This article cites 82 articles, 38 of which can be accessed free at: /content/26/5/326.full.html#ref-list-1 This article has been cited by 2 other HighWire hosted articles Rasip1 regulates vertebrate vascular endothelial junction stability through Epac1-Rap1 signaling Christopher W. Wilson, Leon H. Parker, Christopher J. Hall, Tanya Smyczek, Judy Mak, Ailey Crow, George Posthuma, Ann De Mazière, Meredith Sagolla, Cecile Chalouni, Philip Vitorino, Merone Roose-Girma, Søren Warming, Judith Klumperman, Philip S. Crosier and Weilan Ye Blood, November 21, 2013; 122 (22): 3678-3690. [Abstract] [Full Text] [PDF] Cas and NEDD9 Contribute to Tumor Progression through Dynamic Regulation of the Cytoskeleton Michael S. Guerrero, J. Thomas Parsons and Amy H. Bouton Genes & Cancer, May , 2012; 3 (5-6): 371-381. [Abstract] [Full Text] [PDF] Downloaded from Updated information and services including high resolution figures, can be found at: /content/26/5/326.full.html Additional material and information about Physiology can be found at: http://www.the-aps.org/publications/physiol on August 25, 2014 This information is current as of August 25, 2014. Physiology (formerly published as News in Physiological Science) publishes brief review articles on major physiological developments. It is published bimonthly in February, April, June, August, October, and December by the American Physiological Society, 9650 Rockville Pike, Bethesda MD 20814-3991. Copyright © 2011 by the American Physiological Society. -
Archenteron Precursor Cells Can Organize Secondary Axial Structures in the Sea Urchin Embryo
Development 124, 3461-3470 (1997) 3461 Printed in Great Britain © The Company of Biologists Limited 1997 DEV3652 Archenteron precursor cells can organize secondary axial structures in the sea urchin embryo Hélène Benink1, Gregory Wray2 and Jeff Hardin1,3,* 1Department of Zoology and 3Program in Cell and Molecular Biology, University of Wisconsin, Madison, 1117 West Johnson Street, Madison, WI 53706, USA 2Department of Ecology and Evolution, SUNY, Stony Brook, NY 11794, USA *Author for correspondence: (e-mail: [email protected]) SUMMARY Local cell-cell signals play a crucial role in establishing terning sites within the ectoderm. The ectopic skeletal major tissue territories in early embryos. The sea urchin elements are bilaterally symmetric, and flank the ectopic embryo is a useful model system for studying these inter- archenteron, in some cases resulting in mirror-image, actions in deuterostomes. Previous studies showed that symmetric skeletal elements. Since the induced patterned ectopically implanted micromeres from the 16-cell embryo ectoderm and supernumerary skeletal elements are derived can induce ectopic guts and additional skeletal elements in from the host, the ectopic presumptive archenteron tissue sea urchin embryos. Using a chimeric embryo approach, we can act to ‘organize’ ectopic axial structures in the sea show that implanted archenteron precursors differentiate urchin embryo. autonomously to produce a correctly proportioned and patterned gut. In addition, the ectopically implanted pre- sumptive archenteron tissue induces ectopic skeletal pat- Key words: induction, gastrulation, sea urchin, endoderm INTRODUCTION mapping studies have shown that veg1 descendants contribute tissue to the vegetal regions of the archenteron by the late Progressive refinement of the embryonic body plan via local gastrula stage (Logan and McClay, 1997); by this time veg1 inductive interactions is a common theme among animal and veg2 descendants intermingle within the wall of the archen- embryos. -
Regulative Capacity of the Archenteron During Gastrulation in the Sea Urchin
Development 122, 607-616 (1996) 607 Printed in Great Britain © The Company of Biologists Limited 1996 DEV3313 Regulative capacity of the archenteron during gastrulation in the sea urchin David R. McClay* and Catriona Y. Logan Developmental, Cellular and Molecular Biology Group, LSRC, Duke University, Durham NC 27708, USA *Author for correspondence (e-mail: [email protected]) SUMMARY Gastrulation in the sea urchin involves an extensive ognizable morphology of the archenteron was re-estab- rearrangement of cells of the archenteron giving rise to lished. Long after the archenteron reveals territorial speci- secondary mesenchyme at the archenteron tip followed by fication through expression of specific markers, the endo- the foregut, midgut and hindgut. To examine the regula- dermal cells remain capable of being respecified to other tive capacity of this structure, pieces of the archenteron gut regions. Thus, for much of gastrulation, the gut is con- were removed or transplanted at different stages of gas- ditionally specified. We propose that this regulative ability trulation. After removal of any or all parts of the archen- requires extensive and continuous short-range communi- teron, the remaining veg 1 and/or veg 2 tissue regulated to cation between cells of the archenteron in order to reor- replace the missing parts. Endoderm transplanted to ganize the tissues and position the boundaries of this ectopic positions also regulated to that new position in the structure even after experimental alterations. archenteron. This ability to replace or regulate endoderm did not decline until after full elongation of the archenteron was completed. When replacement occurred, the new gut Key words: morphogenesis, cell lineage, cell fate, differentiation, was smaller relative to the remaining embryo but the rec- specification. -
Myth4-FERM Myosin Based Filopodia Initiation
MyTH4-FERM Myosin based filopodia initiation A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Ashley L. Arthur IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Margaret A. Titus, PhD ADVISOR July 2020 © Ashley L Arthur 2020 ACKNOWLEDGEMENTS I would first and foremost like to advisor my mentor, Dr. Margaret Titus, for her unassailable commitment to training, enthusiasm for science and her sup- port of my career. Meg has been superb advisor, has made me a better scientist and communicator and I genuinely enjoyed working for her. I am grateful for the long list of positive experiences and opportunities I gained while working in the Titus lab. I would like to thank all of my past and present lab mates. Thank you to Hilary Bauer, Sinzi Cornea and Zoe Henrot for welcoming me into the lab when I started and especially to Karl Petersen who share his imaging and analysis ex- pertise. I am so grateful for the help and from my PLA project teammate Livia Songster, you brought such great energy to the project and to the lab. Thanks Casey Eddington, Annika Schroeder for their support, encouragement and help reading and discussing many aspect of this work. Thanks to the University of MN undergraduate students who joined my on research projects over the years espe- cially to Himanshu Jain. I would like to thank Jordan Beach at Loyola, Guillermo Marques, Mark Sanders, for their help with imaging. I thank Ashim Rai for his as- sistance with motor purification and motility assays. -
Chapter 4 Sea Urchin Development Carolyn M
Chapter 4 Sea Urchin Development Carolyn M. Conway Don Igelsrud Department of Biology Department of Biology Virginia Commonwealth University The University of Calgary Richmond, Virginia 23284 USA Calgary, Alberta T2N 1N4 Canada Arthur F. Conway Department of Biology Randolph-Macon College Ashland, Virginia 23005 USA Carolyn M. Conway is currently an Assistant Professor of Biology at Virginia Com- monwealth University where she teaches Animal Embryology, Devetopmental Biology, and Teratology. She received her BS and MA degrees at Longwood College and the College of William and Mary respectively. She received her PhD from the University of Miami where her research involved an ultrastructural study of sea urchin eggs. While completing her doctorate she spent several Summers at the Marine Biological Labo- ratory as a participant in the Fertilization and Gamete Physiology Training Program. Prior to joining the VCU faculty she taught at Iowa State University and Hobart and William Smith Colleges. Her current research involves the relationship between ma- ternal autoimmune disease and birth defects. Don Igelsrud is currently an Instructor of Biology at The University of Calgary where he is in charge of the introductory zoology laboratories. He received his BS degree from the University of Kansas and his MA degree from Washington University. Prior to joining the faculty at The University of Calgary he taught at Delaware Valley College where he developed a sfrong interest in laboratory teaching, and at Northwestern Uni- versity where he was Biology Laboratory Director. His main interests are in increasing awareness and understanding of living phenomena and in finding living organisms that survive well in the laboratory with a minimum of maintenance. -
2. Archenteron Morphogenesis in the Sea Urchin David R
Cell-Cell Interactions in Early Development, pages 15-29 © 1991 Wiley-Liss, Inc. I .f 2. Archenteron Morphogenesis in the Sea Urchin David R. McClay, John Morrill, and Jeff Hardin Department of Zoology, Duke University, Durham, North Carolina 27707 (D .R.M., J.H.); Department of Biology, New College, Sarasota, Florida 33580 (J .M.) INTRODUCTION The progression of development involves an impressive array of morphoge netic rearrangements, each of which involves the coordination of multiple cel lular functions and molecular events. We have been studying gastrulation in the sea urchin embryo as a relatively simple model system in an attempt to understand the sorts of rules observed by an embryo as it performs a single morphogenetic event. To the observer, gastrulation in this embryo involves two major cell movements. First, primary mesenchyme cells ingress and dis playa series of migratory behaviors leading to the assembly of the larval skel eton. Second, invagination of the archenteron leads to the formation of the primitive gut. The ingression and subsequent behavior of primary mesenchyme cells is examined elsewhere in this volume (Ettensohn, Chapter 11). Here we review events associated with formation of the archenteron . In echinoderm embryos, archenteron formation begins with an indentation of the vegetal plate, followed by elongation of the indented area until a tubular archenteron forms that extends into the blastocoel . Elongation continues until the tube reaches a defined, anatomically specific region on the wall of the blastocoel (Fig . I). All through invagination, secondary mesenchyme cells at the tip of the archenteron extend filopodia that make contact with the wall of the blastocoel. -
002 Sempozyum1 5 SON.Qxd
Abstracts www.anatomy.org.tr doi:10.2399/ana.11.001s Abstracts for the Joint Meeting of Anatomical Societies, 19-22 May 2011, Bursa, Turkey Anatomy 2011; 5 Suppl: S1-S171, © 2011 TSACA Opening Lecture New genoarchitectonic viewpoints on the developing hypothalamus Puelles L effects suggests that, rather than being a diencephalic floor ele- ment, the hypothalamus is best understood as a transverse region Department of Human Anatomy, Faculty of lying ventral to the telencephalon and rostral to the dien- Medicine, University of Murcia, Murcia, Spain cephalon; the latter separates it from the midbrain. A number of gene expression patterns observed in the developing forebrain, part of the emergent genoarchitectonic neuroanatomy, have The anatomic concept of the hypothalamus changed consider- revealed the true topologic position of the hypothalamus, as well ably since its earliest definition. Tridimensional reconstructions, as the nature of its fundamental subdivisions. There are interest- experiments and many staining methods have expanded consid- ing parallelisms with genoarchitectonic patterns in the dien- erably the number of anatomical details recognized in this terri- cephalon and midbrain. In all these cases continuous longitudi- tory, probably one of the most complex in the brain. For a long nal domains can be distinguished, as well as a number of antero- time the predominant anatomic view has interpreted the hypo- posterior (transverse) neuromeric units of the neural wall. The thalamus as a longitudinal column at the floor of the dien- hypothalamus has been newly recognized to have two antero- cephalon, connected rostrally with the telencephalon and cau- posterior neuromeric subdivisions, named terminal and pedun- dally with the midbrain.