1
|
Zemann B, Le MLV, Sherlock RE, Baum D, Katija K, Stach T. Evolutionary traces of miniaturization in a giant-Comparative anatomy of brain and brain nerves in Bathochordaeus stygius (Tunicata, Appendicularia). J Morphol 2023; 284:e21598. [PMID: 37313762 DOI: 10.1002/jmor.21598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/04/2023] [Accepted: 05/07/2023] [Indexed: 06/15/2023]
Abstract
Appendicularia comprises 70 marine, invertebrate, chordate species. Appendicularians play important ecological and evolutionary roles, yet their morphological disparity remains understudied. Most appendicularians are small, develop rapidly, and with a stereotyped cell lineage, leading to the hypothesis that Appendicularia derived progenetically from an ascidian-like ancestor. Here, we describe the detailed anatomy of the central nervous system of Bathochordaeus stygius, a giant appendicularian from the mesopelagic. We show that the brain consists of a forebrain with on average smaller and more uniform cells and a hindbrain, in which cell shapes and sizes vary to a greater extent. Cell count for the brain was 102. We demonstrate the presence of three paired brain nerves. Brain nerve 1 traces into the epidermis of the upper lip region and consists of several fibers with some supportive bulb cells in its course. Brain nerve 2 innervates oral sensory organs and brain nerve 3 innervates the ciliary ring of the gill slits and lateral epidermis. Brain nerve 3 is asymmetric, with the right nerve consisting of two neurites originating posterior to the left one that contains three neurites. Similarities and differences to the anatomy of the brain of the model species Oikopleura dioica are discussed. We interpret the small number of cells in the brain of B. stygius as an evolutionary trace of miniaturization and conclude that giant appendicularians evolved from a small, progenetic ancestor that secondarily increased in size within Appendicularia.
Collapse
Affiliation(s)
| | - Mai-Lee Van Le
- Humboldt-Universität zu Berlin, Vergleichende Elektronenmikroskopie, Berlin, Germany
| | - Rob E Sherlock
- Monterey Bay Aquarium Research Institute, Moss Landing, California, USA
| | | | - Kakani Katija
- Monterey Bay Aquarium Research Institute, Moss Landing, California, USA
| | - Thomas Stach
- Humboldt-Universität zu Berlin, Vergleichende Elektronenmikroskopie, Berlin, Germany
| |
Collapse
|
2
|
Nakano H, Isowa Y, Inaba K. JAMBIO and Its Coastal Organism Joint Surveys: Network of Marine Stations Explores Japanese Coastal Biota. Zoolog Sci 2022; 39:1-6. [DOI: 10.2108/zs210069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Hiroaki Nakano
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan
| | - Yukinobu Isowa
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan
| |
Collapse
|
3
|
Onuma TA, Nishida H. Developmental biology of the larvacean Oikopleura dioica: Genome resources, functional screening, and imaging. Dev Growth Differ 2021; 64:67-82. [PMID: 34964127 DOI: 10.1111/dgd.12769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 12/01/2022]
Abstract
The larvacean Oikopleura dioica is a cosmopolitan planktonic chordate and is closely related to vertebrates. It is characterized by a tadpole-shaped morphology with notochord flanked by muscle in the tail and brain on the dorsal side, a short life cycle of five days, a compact genome of approximately 56 Mb, a simple and transparent body with a small number of cells (~4000 in functional juveniles), invariant embryonic cell lineages, and fast development that ensures complete morphogenesis and organ formation 10 h after fertilization. With these features, this marine chordate is a promising and advantageous animal model in which genetic manipulation is feasible. In this review, we introduce relevant resources and modern techniques that have been developed: (1) Genome and transcriptomes. Oikopleura dioica has the smallest genome among non-parasitic metazoans. Its genome databases have been generated using three geographically distant O. dioica populations, and several intra-species sequence differences are becoming evident; (2) Functional genetic knockdown techniques. Comprehensive screening of genes is feasible using ovarian microinjection and double-strand DNA-induced gene knockdown; and (3) Live imaging of embryos and larvae. Application of these techniques has uncovered novel aspects of development, including meiotic cell arrest, left-right patterning, epidermal cell patterning, and mouth formation involving the connection of ectoderm and endoderm sheets. Oikopleura dioca has become very useful for developmental and evolutionary studies in chordates.
Collapse
Affiliation(s)
- Takeshi A Onuma
- Graduate School of Science and Engineering, Faculty of Science, Kagoshima University, Kagoshima, Japan.,Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| |
Collapse
|
4
|
Nishida H, Matsuo M, Konishi S, Ohno N, Manni L, Onuma TA. Germline development during embryogenesis of the larvacean, Oikopleura dioica. Dev Biol 2021; 481:188-200. [PMID: 34755656 DOI: 10.1016/j.ydbio.2021.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/08/2021] [Accepted: 10/24/2021] [Indexed: 11/18/2022]
Abstract
Germ cells develop into eggs and sperms and represent a lineage that survives through multiple generations. Germ cell specification during embryogenesis proceeds through one of two basic modes: either the cell-autonomous mode or the inductive mode. In the cell-autonomous mode, specification of germ cell fate involves asymmetric partitioning of the specialized maternal cytoplasm, known as the germplasm. Oikopleura dioica is a larvacean (class Appendicularia) and a chordate. It is regarded as a promising animal model for studying chordate development because of its short life cycle (5 days) and small genome size (∼60 Mb). We show that their embryos possess germplasm, as observed in ascidians (class Ascidiacea). The vegetal cytoplasm shifted towards the future posterior pole before the first cleavage occurred. A bilateral pair of primordial germ cells (PGC, B11 cells) was formed at the posterior pole at the 32-cell stage through two rounds of unequal cleavage. These B11 cells did not undergo further division before hatching of the tadpole-shaped larvae. The centrosome-attracting body (CAB) is a subcellular structure that contains the germplasm and plays crucial roles in germ cell development in ascidians. The presence of CAB with germplasm was observed in the germline lineage cells of larvaceans via electron microscopy and using extracted embryos. The CAB appeared at the 8-cell stage and persisted until the middle stage of embryogenesis. The antigen for the phosphorylated histone 3 antibody was localized to the CAB and persisted in the PGC until hatching after the CAB disappeared. Maternal snail mRNA, which encodes a transcription factor, was co-localized with the antigen for the H3S28p antibody. Furthermore, we found a novel PGC-specific subcellular structure that we call the germ body (GB). This study thus highlights the conserved and non-conserved features of germline development between ascidians and larvaceans. The rapid development and short life cycle (five days) of O. dioica would open the way to genetically analyze germ cell development in the future.
Collapse
Affiliation(s)
- Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
| | - Masaki Matsuo
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Shohei Konishi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Nobuhiko Ohno
- Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan; Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan
| | - Lucia Manni
- Dipartimento di Biologia, Università degli Studi di Padova, via U. Bassi 58/B, I-35121, Padova, Italy
| | - Takeshi A Onuma
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| |
Collapse
|
5
|
Özpolat BD, Randel N, Williams EA, Bezares-Calderón LA, Andreatta G, Balavoine G, Bertucci PY, Ferrier DEK, Gambi MC, Gazave E, Handberg-Thorsager M, Hardege J, Hird C, Hsieh YW, Hui J, Mutemi KN, Schneider SQ, Simakov O, Vergara HM, Vervoort M, Jékely G, Tessmar-Raible K, Raible F, Arendt D. The Nereid on the rise: Platynereis as a model system. EvoDevo 2021; 12:10. [PMID: 34579780 PMCID: PMC8477482 DOI: 10.1186/s13227-021-00180-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/20/2021] [Indexed: 01/02/2023] Open
Abstract
The Nereid Platynereis dumerilii (Audouin and Milne Edwards (Annales des Sciences Naturelles 1:195-269, 1833) is a marine annelid that belongs to the Nereididae, a family of errant polychaete worms. The Nereid shows a pelago-benthic life cycle: as a general characteristic for the superphylum of Lophotrochozoa/Spiralia, it has spirally cleaving embryos developing into swimming trochophore larvae. The larvae then metamorphose into benthic worms living in self-spun tubes on macroalgae. Platynereis is used as a model for genetics, regeneration, reproduction biology, development, evolution, chronobiology, neurobiology, ecology, ecotoxicology, and most recently also for connectomics and single-cell genomics. Research on the Nereid started with studies on eye development and spiralian embryogenesis in the nineteenth and early twentieth centuries. Transitioning into the molecular era, Platynereis research focused on posterior growth and regeneration, neuroendocrinology, circadian and lunar cycles, fertilization, and oocyte maturation. Other work covered segmentation, photoreceptors and other sensory cells, nephridia, and population dynamics. Most recently, the unique advantages of the Nereid young worm for whole-body volume electron microscopy and single-cell sequencing became apparent, enabling the tracing of all neurons in its rope-ladder-like central nervous system, and the construction of multimodal cellular atlases. Here, we provide an overview of current topics and methodologies for P. dumerilii, with the aim of stimulating further interest into our unique model and expanding the active and vibrant Platynereis community.
Collapse
Affiliation(s)
- B. Duygu Özpolat
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Nadine Randel
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
| | - Elizabeth A. Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Gabriele Andreatta
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9/4, 1030 Vienna, Austria
| | - Guillaume Balavoine
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Paola Y. Bertucci
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - David E. K. Ferrier
- Gatty Marine Laboratory, The Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, Fife, KY16 8LB UK
| | | | - Eve Gazave
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Mette Handberg-Thorsager
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jörg Hardege
- Department of Biological & Marine Sciences, Hull University, Cottingham Road, Hull, HU67RX UK
| | - Cameron Hird
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
| | - Yu-Wen Hsieh
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jerome Hui
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Kevin Nzumbi Mutemi
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Stephan Q. Schneider
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 11529 Taiwan
| | - Oleg Simakov
- Department for Neurosciences and Developmental Biology, University of Vienna, Vienna, Austria
| | - Hernando M. Vergara
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, Howland Street 25, London, W1T 4JG UK
| | - Michel Vervoort
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
| | | | - Florian Raible
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9/4, 1030 Vienna, Austria
| | - Detlev Arendt
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
| |
Collapse
|
6
|
Onuma TA, Nakanishi R, Sasakura Y, Ogasawara M. Nkx2-1 and FoxE regionalize glandular (mucus-producing) and thyroid-equivalent traits in the endostyle of the chordate Oikopleura dioica. Dev Biol 2021; 477:219-231. [PMID: 34107272 DOI: 10.1016/j.ydbio.2021.05.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 11/19/2022]
Abstract
The endostyle is a ventral pharyngeal organ used for internal filter feeding of basal chordates and is considered homologous to the follicular thyroid of vertebrates. It contains mucus-producing (glandular) and thyroid-equivalent regions organized along the dorsoventral (DV) axis. Although thyroid-related genes (Nkx2-1, FoxE, and thyroid peroxidase (TPO)) are known to be expressed in the endostyle, their roles in establishing regionalization within the organ have not been demonstrated. We report that Nkx2-1 and FoxE are essential for establishing DV axial identity in the endostyle of Oikopleura dioica. Genome and expression analyses showed von Willebrand factor-like (vWFL) and TPO/dual oxidase (Duox)/Nkx2-1/FoxE as orthologs of glandular and thyroid-related genes, respectively. Knockdown experiments showed that Nkx2-1 is necessary for the expression of glandular and thyroid-related genes, whereas FoxE is necessary only for thyroid-related genes. Moreover, Nkx2-1 expression is necessary for FoxE expression in larvae during organogenesis. The results demonstrate the essential roles of Nkx2-1 and FoxE in establishing regionalization in the endostyle, including (1) the Nkx2-1-dependent glandular region, and (2) the Nkx2-1/FoxE-dependent thyroid-equivalent region. DV axial regionalization may be responsible for organizing glandular and thyroid-equivalent traits of the pharynx along the DV axis.
Collapse
Affiliation(s)
- Takeshi A Onuma
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan.
| | - Rina Nakanishi
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
| | - Michio Ogasawara
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan.
| |
Collapse
|
7
|
Hudson C, Yasuo H. Neuromesodermal Lineage Contribution to CNS Development in Invertebrate and Vertebrate Chordates. Genes (Basel) 2021; 12:genes12040592. [PMID: 33920662 PMCID: PMC8073528 DOI: 10.3390/genes12040592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Ascidians are invertebrate chordates and the closest living relative to vertebrates. In ascidian embryos a large part of the central nervous system arises from cells associated with mesoderm rather than ectoderm lineages. This seems at odds with the traditional view of vertebrate nervous system development which was thought to be induced from ectoderm cells, initially with anterior character and later transformed by posteriorizing signals, to generate the entire anterior-posterior axis of the central nervous system. Recent advances in vertebrate developmental biology, however, show that much of the posterior central nervous system, or spinal cord, in fact arises from cells that share a common origin with mesoderm. This indicates a conserved role for bi-potential neuromesoderm precursors in chordate CNS formation. However, the boundary between neural tissue arising from these distinct neural lineages does not appear to be fixed, which leads to the notion that anterior-posterior patterning and neural fate formation can evolve independently.
Collapse
|
8
|
Kowarsky M, Anselmi C, Hotta K, Burighel P, Zaniolo G, Caicci F, Rosental B, Neff NF, Ishizuka KJ, Palmeri KJ, Okamoto J, Gordon T, Weissman IL, Quake SR, Manni L, Voskoboynik A. Sexual and asexual development: two distinct programs producing the same tunicate. Cell Rep 2021; 34:108681. [PMID: 33503429 PMCID: PMC7949349 DOI: 10.1016/j.celrep.2020.108681] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 08/24/2020] [Accepted: 12/30/2020] [Indexed: 01/04/2023] Open
Abstract
Colonial tunicates are the only chordate that possess two distinct developmental pathways to produce an adult body: either sexually through embryogenesis or asexually through a stem cell-mediated renewal termed blastogenesis. Using the colonial tunicate Botryllus schlosseri, we combine transcriptomics and microscopy to build an atlas of the molecular and morphological signatures at each developmental stage for both pathways. The general molecular profiles of these processes are largely distinct. However, the relative timing of organogenesis and ordering of tissue-specific gene expression are conserved. By comparing the developmental pathways of B. schlosseri with other chordates, we identify hundreds of putative transcription factors with conserved temporal expression. Our findings demonstrate that convergent morphology need not imply convergent molecular mechanisms but that it showcases the importance that tissue-specific stem cells and transcription factors play in producing the same mature body through different pathways.
Collapse
Affiliation(s)
- Mark Kowarsky
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Chiara Anselmi
- Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy; Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA
| | - Kohji Hotta
- Department of Biosciences and Informatics, Keio University, Yokohama 223-8522, Japan
| | - Paolo Burighel
- Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy
| | - Giovanna Zaniolo
- Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy
| | - Federico Caicci
- Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy
| | - Benyamin Rosental
- Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA; The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Center for Regenerative Medicine and Stem Cells, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Norma F Neff
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Katherine J Ishizuka
- Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA
| | - Karla J Palmeri
- Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA
| | | | - Tal Gordon
- Zoology Department, Tel Aviv University, Tel Aviv 69978, Israel
| | - Irving L Weissman
- Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Stephen R Quake
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA; Departments of Applied Physics and Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Lucia Manni
- Dipartimento di Biologia, Università degli Studi di Padova, 35122 Padova, Italy.
| | - Ayelet Voskoboynik
- Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| |
Collapse
|
9
|
Collinet C, Lecuit T. Programmed and self-organized flow of information during morphogenesis. Nat Rev Mol Cell Biol 2021; 22:245-265. [PMID: 33483696 DOI: 10.1038/s41580-020-00318-6] [Citation(s) in RCA: 107] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2020] [Indexed: 11/09/2022]
Abstract
How the shape of embryos and organs emerges during development is a fundamental question that has fascinated scientists for centuries. Tissue dynamics arise from a small set of cell behaviours, including shape changes, cell contact remodelling, cell migration, cell division and cell extrusion. These behaviours require control over cell mechanics, namely active stresses associated with protrusive, contractile and adhesive forces, and hydrostatic pressure, as well as material properties of cells that dictate how cells respond to active stresses. In this Review, we address how cell mechanics and the associated cell behaviours are robustly organized in space and time during tissue morphogenesis. We first outline how not only gene expression and the resulting biochemical cues, but also mechanics and geometry act as sources of morphogenetic information to ultimately define the time and length scales of the cell behaviours driving morphogenesis. Next, we present two idealized modes of how this information flows - how it is read out and translated into a biological effect - during morphogenesis. The first, akin to a programme, follows deterministic rules and is hierarchical. The second follows the principles of self-organization, which rests on statistical rules characterizing the system's composition and configuration, local interactions and feedback. We discuss the contribution of these two modes to the mechanisms of four very general classes of tissue deformation, namely tissue folding and invagination, tissue flow and extension, tissue hollowing and, finally, tissue branching. Overall, we suggest a conceptual framework for understanding morphogenetic information that encapsulates genetics and biochemistry as well as mechanics and geometry as information modules, and the interplay of deterministic and self-organized mechanisms of their deployment, thereby diverging considerably from the traditional notion that shape is fully encoded and determined by genes.
Collapse
Affiliation(s)
- Claudio Collinet
- Aix-Marseille Université & CNRS, IBDM - UMR7288 & Turing Centre for Living Systems, Campus de Luminy Case 907, Marseille, France
| | - Thomas Lecuit
- Aix-Marseille Université & CNRS, IBDM - UMR7288 & Turing Centre for Living Systems, Campus de Luminy Case 907, Marseille, France. .,Collège de France, Paris, France.
| |
Collapse
|
10
|
Wang K, Tomura R, Chen W, Kiyooka M, Ishizaki H, Aizu T, Minakuchi Y, Seki M, Suzuki Y, Omotezako T, Suyama R, Masunaga A, Plessy C, Luscombe NM, Dantec C, Lemaire P, Itoh T, Toyoda A, Nishida H, Onuma TA. A genome database for a Japanese population of the larvacean Oikopleura dioica. Dev Growth Differ 2020; 62:450-461. [PMID: 32677034 DOI: 10.1111/dgd.12689] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 06/10/2020] [Accepted: 06/10/2020] [Indexed: 01/01/2023]
Abstract
The larvacean Oikopleura dioica is a planktonic chordate and is a tunicate that belongs to the closest relatives to vertebrates. Its simple and transparent body, invariant embryonic cell lineages, and short life cycle of 5 days make it a promising model organism for the study of developmental biology. The genome browser OikoBase was established in 2013 using Norwegian O. dioica. However, genome information for other populations is not available, even though many researchers have studied local populations. In the present study, we sequenced using Illumina and PacBio RSII technologies the genome of O. dioica from a southwestern Japanese population that was cultured in our laboratory for 3 years. The genome of Japanese O. dioica was assembled into 576 scaffold sequences with a total length and N50 length of 56.6 and 1.5 Mb, respectively. A total of 18,743 gene models (transcript models) were predicted in the genome assembly, named OSKA2016. In addition, 19,277 non-redundant transcripts were assembled using RNA-seq data. The OSKA2016 has global sequence similarity of only 86.5% when compared with the OikoBase, highlighting the sequence difference between the two far distant O. dioica populations on the globe. The genome assembly, transcript assembly, and transcript models were incorporated into ANISEED (https://www.aniseed.cnrs.fr/) for genome browsing and BLAST searches. Mapping of reads obtained from male- or female-specific genome libraries yielded male-specific scaffolds in the OSKA2016 and revealed that over 2.6 Mb of sequence were included in the male-specific Y-region. The genome and transcriptome resources from two distinct populations will be useful datasets for developmental biology, evolutionary biology, and molecular ecology using this model organism.
Collapse
Affiliation(s)
- Kai Wang
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Ryo Tomura
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Wei Chen
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Miho Kiyooka
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Hinako Ishizaki
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Tomoyuki Aizu
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yohei Minakuchi
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Masahide Seki
- Laboratory of Systems Genomics, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Yutaka Suzuki
- Laboratory of Systems Genomics, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Tatsuya Omotezako
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Ritsuko Suyama
- Genomics and Regulatory Systems Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa, Japan
| | - Aki Masunaga
- Genomics and Regulatory Systems Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa, Japan
| | - Charles Plessy
- Genomics and Regulatory Systems Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa, Japan
| | - Nicholas M Luscombe
- Genomics and Regulatory Systems Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami-gun, Okinawa, Japan
| | - Christelle Dantec
- Centre de Recherches de Biochimie Macromoleculaire (CRBM), UMR5237, CNRS-Universite de Montpellier, Montpellier, France
| | - Patrick Lemaire
- Centre de Recherches de Biochimie Macromoleculaire (CRBM), UMR5237, CNRS-Universite de Montpellier, Montpellier, France
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Takeshi A Onuma
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| |
Collapse
|
11
|
A chordate species lacking Nodal utilizes calcium oscillation and Bmp for left-right patterning. Proc Natl Acad Sci U S A 2020; 117:4188-4198. [PMID: 32029598 DOI: 10.1073/pnas.1916858117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Larvaceans are chordates with a tadpole-like morphology. In contrast to most chordates of which early embryonic morphology is bilaterally symmetric and the left-right (L-R) axis is specified by the Nodal pathway later on, invariant L-R asymmetry emerges in four-cell embryos of larvaceans. The asymmetric cell arrangements exist through development of the tailbud. The tail thus twists 90° in a counterclockwise direction relative to the trunk, and the tail nerve cord localizes on the left side. Here, we demonstrate that larvacean embryos have nonconventional L-R asymmetries: 1) L- and R-cells of the two-cell embryo had remarkably asymmetric cell fates; 2) Ca2+ oscillation occurred through embryogenesis; 3) Nodal, an evolutionarily conserved left-determining gene, was absent in the genome; and 4) bone morphogenetic protein gene (Bmp) homolog Bmp.a showed right-sided expression in the tailbud and larvae. We also showed that Ca2+ oscillation is required for Bmp.a expression, and that BMP signaling suppresses ectopic expression of neural genes. These results indicate that there is a chordate species lacking Nodal that utilizes Ca2+ oscillation and Bmp.a for embryonic L-R patterning. The right-side Bmp.a expression may have arisen via cooption of conventional BMP signaling in order to restrict neural gene expression on the left side.
Collapse
|
12
|
Gordon R, Gordon NK. The differentiation code. Biosystems 2019; 184:104013. [DOI: 10.1016/j.biosystems.2019.104013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/30/2019] [Accepted: 08/03/2019] [Indexed: 12/24/2022]
|
13
|
Savelieva AV. An electron microscopic study of early gonadogenesis in the hermaphroditic appendicularian Oikopleura gracilis(Tunicata, Oikopleuridae). INVERTEBR REPROD DEV 2019. [DOI: 10.1080/07924259.2018.1561529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Anna V. Savelieva
- National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
| |
Collapse
|
14
|
Antero-posterior ectoderm patterning by canonical Wnt signaling during ascidian development. PLoS Genet 2019; 15:e1008054. [PMID: 30925162 PMCID: PMC6457572 DOI: 10.1371/journal.pgen.1008054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/10/2019] [Accepted: 02/28/2019] [Indexed: 01/21/2023] Open
Abstract
Wnt/β-catenin signaling is an ancient pathway in metazoans and controls various developmental processes, in particular the establishment and patterning of the embryonic primary axis. In vertebrates, a graded Wnt activity from posterior to anterior endows cells with positional information in the central nervous system. Recent studies in hemichordates support a conserved role for Wnt/β-catenin in ectoderm antero-posterior patterning at the base of the deuterostomes. Ascidians are marine invertebrates and the closest relatives of vertebrates. By combining gain- and loss-of-function approaches, we have determined the role of Wnt/β-catenin in patterning the three ectoderm derivatives of the ascidian Ciona intestinalis, central nervous system, peripheral nervous system and epidermis. Activating Wnt/β-catenin signaling from gastrulation led to a dramatic transformation of the ectoderm with a loss of anterior identities and a reciprocal anterior extension of posterior identities, consistent with studies in other metazoans. Surprisingly, inhibiting Wnt signaling did not produce a reciprocal anteriorization of the embryo with a loss of more posterior identities like in vertebrates and hemichordate. Epidermis patterning was overall unchanged. Only the identity of two discrete regions of the central nervous system, the anteriormost and the posteriormost regions, were under the control of Wnt. Finally, the caudal peripheral nervous system, while being initially Wnt dependent, formed normally. Our results show that the Ciona embryonic ectoderm responds to Wnt activation in a manner that is compatible with the proposed function for this pathway at the base of the deuterostomes. However, possibly because of its fast and divergent mode of development that includes extensive use of maternal determinants, the overall antero-posterior patterning of the Ciona ectoderm is Wnt independent, and Wnt/β-catenin signaling controls the formation of some sub-domains. Our results thus indicate that there has likely been a drift in the developmental systems controlling ectoderm patterning in the lineage leading to ascidians. The Wnt/β-catenin pathway is a system of cell-cell communication. It has an ancient origin in animals and plays multiple roles during embryogenesis and adult life. In particular, it is involved in determining, in the vertebrate embryo, the identity of the different parts of the body and their relative positions along the antero-posterior axis. We have investigated in an ascidian (or sea squirt) species, a marine invertebrate that is closely related to vertebrates, whether this pathway had a similar role. Like in vertebrates, activating Wnt/β-catenin led to a posteriorization of the embryo with a loss of anterior structures. By contrast, unlike vertebrates, ascidian embryos formed rather normally following Wnt/β-catenin inactivation. Since hemichordates (or acorn worms), earlier divergent invertebrates, use Wnt/β-catenin in a manner comparable to vertebrates, it is in the ascidian lineage that changes have occurred. Consequently, ascidians build an antero-posterior axis, very similarly organized to that of vertebrates, but in a different way.
Collapse
|
15
|
Ferrández-Roldán A, Martí-Solans J, Cañestro C, Albalat R. Oikopleura dioica: An Emergent Chordate Model to Study the Impact of Gene Loss on the Evolution of the Mechanisms of Development. Results Probl Cell Differ 2019; 68:63-105. [PMID: 31598853 DOI: 10.1007/978-3-030-23459-1_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The urochordate Oikopleura dioica is emerging as a nonclassical animal model in the field of evolutionary developmental biology (a.k.a. evo-devo) especially attractive for investigating the impact of gene loss on the evolution of mechanisms of development. This is because this organism fulfills the requirements of an animal model (i.e., has a simple and accessible morphology, a short generation time and life span, and affordable culture in the laboratory and amenable experimental manipulation), but also because O. dioica occupies a key phylogenetic position to understand the diversification and origin of our own phylum, the chordates. During its evolution, O. dioica genome has suffered a drastic process of compaction, becoming the smallest known chordate genome, a process that has been accompanied by exacerbating amount of gene losses. Interestingly, however, despite the extensive gene losses, including entire regulatory pathways essential for the embryonic development of other chordates, O. dioica retains the typical chordate body plan. This unexpected situation led to the formulation of the so-called inverse paradox of evo-devo, that is, when a genetic diversity is able to maintain a phenotypic unity. This chapter reviews the biological features of O. dioica as a model animal, along with the current data on the evolution of its genes and genome. We pay special attention to the numerous examples of gene losses that have taken place during the evolution of this unique animal model, which is helping us to understand to which the limits of evo-devo can be pushed off.
Collapse
Affiliation(s)
- Alfonso Ferrández-Roldán
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Josep Martí-Solans
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Cristian Cañestro
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Ricard Albalat
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain.
| |
Collapse
|
16
|
Oonuma K, Kusakabe TG. Spatio-temporal regulation of Rx and mitotic patterns shape the eye-cup of the photoreceptor cells in Ciona. Dev Biol 2018; 445:245-255. [PMID: 30502325 DOI: 10.1016/j.ydbio.2018.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/18/2018] [Accepted: 11/18/2018] [Indexed: 10/27/2022]
Abstract
The ascidian larva has a pigmented ocellus comprised of a cup-shaped array of approximately 30 photoreceptor cells, a pigment cell, and three lens cells. Morphological, physiological and molecular evidence has suggested evolutionary kinship between the ascidian larval photoreceptors and vertebrate retinal and/or pineal photoreceptors. Rx, an essential factor for vertebrate photoreceptor development, has also been suggested to be involved in the development of the ascidian photoreceptor cells, but a recent revision of the photoreceptor cell lineage raised a crucial discrepancy between the reported expression patterns of Rx and the cell lineage. Here, we report spatio-temporal expression patterns of Rx at single-cell resolution along with mitotic patterns up to the final division of the photoreceptor-lineage cells in Ciona. The expression of Rx commences in non-photoreceptor a-lineage cells on the right side of the anterior sensory vesicle at the early tailbud stage. At the mid tailbud stage, Rx begins to be expressed in the A-lineage photoreceptor cell progenitors located on the right side of the posterior sensory vesicle. Thus, Rx is specifically but not exclusively expressed in the photoreceptor-lineage cells in the ascidian embryo. Two cis-regulatory modules are shown to be important for the photoreceptor-lineage expression of Rx. The cell division patterns of the photoreceptor-lineage cells rationally explain the generation of the cup-shaped structure of the pigmented ocellus. The present findings demonstrate the complete cell lineage of the ocellus photoreceptor cells and provide a framework elucidating the molecular and cellular mechanisms of photoreceptor development in Ciona.
Collapse
Affiliation(s)
- Kouhei Oonuma
- Institute for Integrative Neurobiology and Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan.
| | - Takehiro G Kusakabe
- Institute for Integrative Neurobiology and Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan.
| |
Collapse
|
17
|
Cell differentiation processes as spatial networks: Identifying four-dimensional structure in embryogenesis. Biosystems 2018; 173:235-246. [DOI: 10.1016/j.biosystems.2018.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/15/2018] [Accepted: 09/20/2018] [Indexed: 11/24/2022]
|
18
|
Alicea B, Gordon R. Quantifying Mosaic Development: Towards an Evo-Devo Postmodern Synthesis of the Evolution of Development via Differentiation Trees of Embryos. BIOLOGY 2016; 5:E33. [PMID: 27548240 PMCID: PMC5037352 DOI: 10.3390/biology5030033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 07/04/2016] [Accepted: 08/09/2016] [Indexed: 01/28/2023]
Abstract
Embryonic development proceeds through a series of differentiation events. The mosaic version of this process (binary cell divisions) can be analyzed by comparing early development of Ciona intestinalis and Caenorhabditis elegans. To do this, we reorganize lineage trees into differentiation trees using the graph theory ordering of relative cell volume. Lineage and differentiation trees provide us with means to classify each cell using binary codes. Extracting data characterizing lineage tree position, cell volume, and nucleus position for each cell during early embryogenesis, we conduct several statistical analyses, both within and between taxa. We compare both cell volume distributions and cell volume across developmental time within and between single species and assess differences between lineage tree and differentiation tree orderings. This enhances our understanding of the differentiation events in a model of pure mosaic embryogenesis and its relationship to evolutionary conservation. We also contribute several new techniques for assessing both differences between lineage trees and differentiation trees, and differences between differentiation trees of different species. The results suggest that at the level of differentiation trees, there are broad similarities between distantly related mosaic embryos that might be essential to understanding evolutionary change and phylogeny reconstruction. Differentiation trees may therefore provide a basis for an Evo-Devo Postmodern Synthesis.
Collapse
Affiliation(s)
- Bradly Alicea
- Orthogonal Research, 1408 Rosewood Drive, Champaign, IL 61821, USA.
- OpenWorm Foundation, Cyberspace, San Diego, CA 92110, USA.
| | - Richard Gordon
- Gulf Specimen Marine Laboratory & Aquarium, 222 Clark Drive, Panacea, FL 32346, USA.
- C.S. Mott Center for Human Growth & Development, Department of Obstetrics & Gynecology, Wayne State University, 275 E. Hancock, Detroit, MI 48201, USA.
| |
Collapse
|
19
|
Gordon NK, Gordon R. The organelle of differentiation in embryos: the cell state splitter. Theor Biol Med Model 2016; 13:11. [PMID: 26965444 PMCID: PMC4785624 DOI: 10.1186/s12976-016-0037-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/27/2016] [Indexed: 12/16/2022] Open
Abstract
The cell state splitter is a membraneless organelle at the apical end of each epithelial cell in a developing embryo. It consists of a microfilament ring and an intermediate filament ring subtending a microtubule mat. The microtubules and microfilament ring are in mechanical opposition as in a tensegrity structure. The cell state splitter is bistable, perturbations causing it to contract or expand radially. The intermediate filament ring provides metastability against small perturbations. Once this snap-through organelle is triggered, it initiates signal transduction to the nucleus, which changes gene expression in one of two readied manners, causing its cell to undergo a step of determination and subsequent differentiation. The cell state splitter also triggers the cell state splitters of adjacent cells to respond, resulting in a differentiation wave. Embryogenesis may be represented then as a bifurcating differentiation tree, each edge representing one cell type. In combination with the differentiation waves they propagate, cell state splitters explain the spatiotemporal course of differentiation in the developing embryo. This review is excerpted from and elaborates on "Embryogenesis Explained" (World Scientific Publishing, Singapore, 2016).
Collapse
Affiliation(s)
| | - Richard Gordon
- />Retired, University of Manitoba, Winnipeg, Canada
- />Embryogenesis Center, Gulf Specimen Aquarium & Marine Laboratory, 222 Clark Drive, Panacea, FL 32346 USA
- />C.S. Mott Center for Human Growth & Development, Department of Obstetrics & Gynecology, Wayne State University, 275 E. Hancock, Detroit, MI 48201 USA
| |
Collapse
|
20
|
Stach T, Anselmi C. High-precision morphology: bifocal 4D-microscopy enables the comparison of detailed cell lineages of two chordate species separated for more than 525 million years. BMC Biol 2015; 13:113. [PMID: 26700477 PMCID: PMC4690324 DOI: 10.1186/s12915-015-0218-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/08/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Understanding the evolution of divergent developmental trajectories requires detailed comparisons of embryologies at appropriate levels. Cell lineages, the accurate visualization of cleavage patterns, tissue fate restrictions, and morphogenetic movements that occur during the development of individual embryos are currently available for few disparate animal taxa, encumbering evolutionarily meaningful comparisons. Tunicates, considered to be close relatives of vertebrates, are marine invertebrates whose fossil record dates back to 525 million years ago. Life-history strategies across this subphylum are radically different, and include biphasic ascidians with free swimming larvae and a sessile adult stage, and the holoplanktonic larvaceans. Despite considerable progress, notably on the molecular level, the exact extent of evolutionary conservation and innovation during embryology remain obscure. RESULTS Here, using the innovative technique of bifocal 4D-microscopy, we demonstrate exactly which characteristics in the cell lineages of the ascidian Phallusia mammillata and the larvacean Oikopleura dioica were conserved and which were altered during evolution. Our accurate cell lineage trees in combination with detailed three-dimensional representations clearly identify conserved correspondence in relative cell position, cell identity, and fate restriction in several lines from all prospective larval tissues. At the same time, we precisely pinpoint differences observable at all levels of development. These differences comprise fate restrictions, tissue types, complex morphogenetic movement patterns, numerous cases of heterochronous acceleration in the larvacean embryo, and differences in bilateral symmetry. CONCLUSIONS Our results demonstrate in extraordinary detail the multitude of developmental levels amenable to evolutionary innovation, including subtle changes in the timing of fate restrictions as well as dramatic alterations in complex morphogenetic movements. We anticipate that the precise spatial and temporal cell lineage data will moreover serve as a high-precision guide to devise experimental investigations of other levels, such as molecular interactions between cells or changes in gene expression underlying the documented structural evolutionary changes. Finally, the quantitative amount of digital high-precision morphological data will enable and necessitate software-based similarity assessments as the basis of homology hypotheses.
Collapse
Affiliation(s)
- Thomas Stach
- Institut für Biologie, Kompetenzzentrum Elektronenmikroskopie, Humboldt-Universität zu Berlin, Philippstrasse 13, Haus 14, 10115, Berlin, Germany.
| | - Chiara Anselmi
- Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
| |
Collapse
|
21
|
Maternal and zygotic transcriptomes in the appendicularian, Oikopleura dioica: novel protein-encoding genes, intra-species sequence variations, and trans-spliced RNA leader. Dev Genes Evol 2015; 225:149-59. [PMID: 26032664 DOI: 10.1007/s00427-015-0502-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
RNA sequencing analysis was carried out to characterize egg and larval transcriptomes in the appendicularian, Oikopleura dioica, a planktonic chordate, which is characterized by rapid development and short life cycle of 5 days, using a Japanese population of the organism. De novo transcriptome assembly matched with 16,423 proteins corresponding to 95.4% of the protein-encoding genes deposited in the OikoBase, the genome database of the Norwegian population. Nucleotide and amino acid sequence identities between the Japanese and Norwegian O. dioica were estimated to be around 91.0 and 94.8%, respectively. We discovered 175 novel protein-encoding genes: 144 unigenes were common to both the Japanese and Norwegian populations, whereas 31 unigenes were not found in the OikoBase genome reference. Among the total 12,311 unigenes, approximately 63% were detected in egg-stage RNAs, whereas 99% were detected in larval stage RNAs; 3772 genes were up-regulated, and 1336 genes were down-regulated more than four-fold in the larvae. Gene ontology analyses characterized gene activities in these two developmental stages. We found a messenger RNA (mRNA) 5' trans-spliced leader, which was observed in 40.8% of the total unique transcripts. It showed preferential linkage to adenine at the 5' ends of the downstream exons. Trans-splicing was observed more frequently in egg mRNAs compared with larva-specific mRNAs.
Collapse
|
22
|
Kumano G. Evolution of germline segregation processes in animal development. Dev Growth Differ 2015; 57:324-32. [DOI: 10.1111/dgd.12211] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/05/2015] [Accepted: 03/05/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Gaku Kumano
- Asamushi Research Center for Marine Biology; Graduate School of Life Science; Tohoku University; 9 Sakamoto Asamushi Aomori 039-3501 Japan
| |
Collapse
|
23
|
Kuratani S, Agata K. Special issue featuring Zoological Society Award reviews. Zoolog Sci 2015; 31:623. [PMID: 25284380 DOI: 10.2108/066.031.1001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Shigeru Kuratani
- 1 Editor-in-Chief, Zoological Science, Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | | |
Collapse
|