1
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Perillo M, Swartz SZ, Pieplow C, Wessel GM. Molecular mechanisms of tubulogenesis revealed in the sea star hydro-vascular organ. Nat Commun 2023; 14:2402. [PMID: 37160908 PMCID: PMC10170166 DOI: 10.1038/s41467-023-37947-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 04/06/2023] [Indexed: 05/11/2023] Open
Abstract
A fundamental goal in the organogenesis field is to understand how cells organize into tubular shapes. Toward this aim, we have established the hydro-vascular organ in the sea star Patiria miniata as a model for tubulogenesis. In this animal, bilateral tubes grow out from the tip of the developing gut, and precisely extend to specific sites in the larva. This growth involves cell migration coupled with mitosis in distinct zones. Cell proliferation requires FGF signaling, whereas the three-dimensional orientation of the organ depends on Wnt signaling. Specification and maintenance of tube cell fate requires Delta/Notch signaling. Moreover, we identify target genes of the FGF pathway that contribute to tube morphology, revealing molecular mechanisms for tube outgrowth. Finally, we report that FGF activates the Six1/2 transcription factor, which serves as an evolutionarily ancient regulator of branching morphogenesis. This study uncovers distinct mechanisms of tubulogenesis in vivo and we propose that cellular dynamics in the sea star hydro-vascular organ represents a key comparison for understanding the evolution of vertebrate organs.
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Affiliation(s)
- Margherita Perillo
- Department of Molecular, Cellular Biology and Biochemistry, BioMed Division, Brown University, 185 Meeting Street, Providence, RI, 02912, USA.
- Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA.
| | - S Zachary Swartz
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
- Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Cosmo Pieplow
- Department of Molecular, Cellular Biology and Biochemistry, BioMed Division, Brown University, 185 Meeting Street, Providence, RI, 02912, USA
| | - Gary M Wessel
- Department of Molecular, Cellular Biology and Biochemistry, BioMed Division, Brown University, 185 Meeting Street, Providence, RI, 02912, USA.
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2
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Foster S, Oulhen N, Fresques T, Zaki H, Wessel G. Single-cell RNA-sequencing analysis of early sea star development. Development 2022; 149:dev200982. [PMID: 36399063 PMCID: PMC9845752 DOI: 10.1242/dev.200982] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/17/2022] [Indexed: 11/21/2022]
Abstract
Echinoderms represent a broad phylum with many tractable features to test evolutionary changes and constraints. Here, we present a single-cell RNA-sequencing analysis of early development in the sea star Patiria miniata, to complement the recent analysis of two sea urchin species. We identified 20 cell states across six developmental stages from 8 hpf to mid-gastrula stage, using the analysis of 25,703 cells. The clusters were assigned cell states based on known marker gene expression and by in situ RNA hybridization. We found that early (morula, 8-14 hpf) and late (blastula-to-mid-gastrula) cell states are transcriptionally distinct. Cells surrounding the blastopore undergo rapid cell state changes that include endomesoderm diversification. Of particular import to understanding germ cell specification is that we never see Nodal pathway members within Nanos/Vasa-positive cells in the region known to give rise to the primordial germ cells (PGCs). The results from this work contrast the results of PGC specification in the sea urchin, and the dataset presented here enables deeper comparative studies in tractable developmental models for testing a variety of developmental mechanisms.
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Affiliation(s)
- Stephany Foster
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Nathalie Oulhen
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Tara Fresques
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Hossam Zaki
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Gary Wessel
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
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3
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Meyer A, Hinman V. The arm of the starfish: The far-reaching applications of Patiria miniata as a model system in evolutionary, developmental, and regenerative biology. Curr Top Dev Biol 2022; 147:523-543. [PMID: 35337461 DOI: 10.1016/bs.ctdb.2022.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Many species of echinoderms have long been considered model research organisms in biology. Historically, much of this research has focused on the embryology of sea urchins and the use of their extensive gene regulatory networks as a tool to understand how the genome controls cell state specification and patterning. The establishment of Patiria miniata, the bat sea star, as a research organism has allowed us to expand on the concepts explored with sea urchins, viewing these genetic networks through a comparative lens, gaining great insight into the evolutionary mechanisms that shape developmental diversity. Extensive molecular tools have been developed in P. miniata, designed to explore gene expression dynamics and build gene regulatory networks. Echinoderms also have a robust set of bioinformatic and computational resources, centered around echinobase.org, an extensive database containing multiomic, developmental, and experimental resources for researchers. In addition to comparative evolutionary development, P. miniata is a promising system in its own right for studying whole body regeneration, metamorphosis and body plan development, as well as marine disease.
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Affiliation(s)
- Anne Meyer
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Veronica Hinman
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States.
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4
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Emura N, Yajima M. Micromere formation and its evolutionary implications in the sea urchin. Curr Top Dev Biol 2022; 146:211-238. [PMID: 35152984 PMCID: PMC8868499 DOI: 10.1016/bs.ctdb.2021.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The micromeres of the sea urchin embryo are distinct from other blastomeres. After they arise through an asymmetric cell division at the 8- to 16-cell stage, micromeres immediately function as organizers. They also commit themselves to specific cell fates such as larval skeletogenic cells and primordial germ cells, while other blastomeres remain plastic and uncommitted at the 16-cell stage. In the phylum Echinodermata, only the sea urchin (class Echinoidea) embryo forms micromeres that serve as apparent organizers during early embryogenesis. Therefore, it is considered that micromeres are the derived features and that modification(s) of the developmental system allowed evolutionary introduction of this unique cell lineage. In this chapter, we summarize the both historic and recent observations that demonstrate unique properties of micromeres and discuss how this lineage of micromeres may have arisen during echinoderm evolution.
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5
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Zhao J, Lu P, Wan C, Huang Y, Cui M, Yang X, Hu Y, Zheng Y, Dong J, Wang M, Zhang S, Liu Z, Bian S, Wang X, Wang R, Ren S, Wang D, Yao Z, Chang G, Tang F, Zhao XY. Cell-fate transition and determination analysis of mouse male germ cells throughout development. Nat Commun 2021; 12:6839. [PMID: 34824237 PMCID: PMC8617176 DOI: 10.1038/s41467-021-27172-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 11/08/2021] [Indexed: 12/31/2022] Open
Abstract
Mammalian male germ cell development is a stepwise cell-fate transition process; however, the full-term developmental profile of male germ cells remains undefined. Here, by interrogating the high-precision transcriptome atlas of 11,598 cells covering 28 critical time-points, we demonstrate that cell-fate transition from mitotic to post-mitotic primordial germ cells is accompanied by transcriptome-scale reconfiguration and a transitional cell state. Notch signaling pathway is essential for initiating mitotic arrest and the maintenance of male germ cells' identities. Ablation of HELQ induces developmental arrest and abnormal transcriptome reprogramming of male germ cells, indicating the importance of cell cycle regulation for proper cell-fate transition. Finally, systematic human-mouse comparison reveals potential regulators whose deficiency contributed to human male infertility via mitotic arrest regulation. Collectively, our study provides an accurate and comprehensive transcriptome atlas of the male germline cycle and allows for an in-depth understanding of the cell-fate transition and determination underlying male germ cell development.
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Affiliation(s)
- Jiexiang Zhao
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Ping Lu
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Biomedical Pioneering Innovation Center, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, 100871, Beijing, P. R. China
| | - Cong Wan
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Yaping Huang
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Manman Cui
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Xinyan Yang
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Yuqiong Hu
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Biomedical Pioneering Innovation Center, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, 100871, Beijing, P. R. China
| | - Yi Zheng
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Ji Dong
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Biomedical Pioneering Innovation Center, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, 100871, Beijing, P. R. China
| | - Mei Wang
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Shu Zhang
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Biomedical Pioneering Innovation Center, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, 100871, Beijing, P. R. China
| | - Zhaoting Liu
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Shuhui Bian
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, P. R. China
| | - Xiaoman Wang
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Rui Wang
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, P. R. China
| | - Shaofang Ren
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Dazhuang Wang
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Zhaokai Yao
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China
| | - Gang Chang
- Department of Biochemistry and Molecular Biology, Shenzhen University Health Science Center, 518060, Shenzhen, Guangdong, P. R. China.
| | - Fuchou Tang
- Beijing Advanced Innovation Center for Genomics (ICG), School of Life Sciences, Peking University, 100871, Beijing, P. R. China.
- Biomedical Pioneering Innovation Center, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, 100871, Beijing, P. R. China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, P. R. China.
| | - Xiao-Yang Zhao
- State Key Laboratory of Organ Failure Research, Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China.
- Guangdong Key Laboratory of Construction and Detection in Tissue Engineering, Southern Medical University, 510515, Guangzhou, Guangdong, P. R. China.
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory (GRMH-GDL), 510700, Guangzhou, Guangdong, P. R. China.
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6
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Bronchain O, Philippe-Caraty L, Anquetil V, Ciapa B. Precise regulation of presenilin expression is required for sea urchin early development. J Cell Sci 2021; 134:jcs258382. [PMID: 34313316 DOI: 10.1242/jcs.258382] [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: 01/07/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022] Open
Abstract
Presenilins (PSENs) are widely expressed across eukaryotes. Two PSENs are expressed in humans, where they play a crucial role in Alzheimer's disease (AD). Each PSEN can be part of the γ-secretase complex, which has multiple substrates, including Notch and amyloid-β precursor protein (AβPP) - the source of amyloid-β (Aβ) peptides that compose the senile plaques during AD. PSENs also interact with various proteins independently of their γ-secretase activity. They can then be involved in numerous cellular functions, which makes their role in a given cell and/or organism complex to decipher. We have established the Paracentrotus lividus sea urchin embryo as a new model to study the role of PSEN. In the sea urchin embryo, the PSEN gene is present in unduplicated form and encodes a protein highly similar to human PSENs. Our results suggest that PSEN expression must be precisely tuned to control the course of the first mitotic cycles and the associated intracellular Ca2+ transients, the execution of gastrulation and, probably in association with ciliated cells, the establishment of the pluteus. We suggest that it would be relevant to study the role of PSEN within the gene regulatory network deciphered in the sea urchin.
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Affiliation(s)
- Odile Bronchain
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Laetitia Philippe-Caraty
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Vincent Anquetil
- Sorbonne Université, Inserm U1127, CNRS UMR 7225, Institut du Cerveau (ICM), F-75013, Paris, France
| | - Brigitte Ciapa
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
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7
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Schrankel CS, Hamdoun A. Early patterning of ABCB, ABCC, and ABCG transporters establishes unique territories of small molecule transport in embryonic mesoderm and endoderm. Dev Biol 2021; 472:115-124. [PMID: 33460641 DOI: 10.1016/j.ydbio.2020.12.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/08/2020] [Accepted: 12/22/2020] [Indexed: 01/16/2023]
Abstract
Directed intercellular movement of diverse small molecules, including metabolites, signal molecules and xenobiotics, is a key feature of multicellularity. Networks of small molecule transporters (SMTs), including several ATP Binding Cassette (ABC) transporters, are central to this process. While small molecule transporters are well described in differentiated organs, little is known about their patterns of expression in early embryogenesis. Here we report the pattern of ABC-type SMT expression and activity during the early development of sea urchins. Of the six major ABCs in this embryo (ABCB1, -B4, -C1, -C4, -C5 and -G2), three expression patterns were observed: 1) ABCB1 and ABCC1 are first expressed ubiquitously, and then become enriched in endoderm and ectoderm-derived structures. 2) ABCC4 and ABCC5 are restricted to a ring of mesoderm in the blastula and ABCC4 is later expressed in the coelomic pouches, the embryonic niche of the primordial germ cells. 3) ABCB4 and ABCG2 are expressed exclusively in endoderm-fated cells. Assays with fluorescent substrates and inhibitors of transporters revealed a ring of ABCC4 efflux activity emanating from ABCC4+ mesodermal cells. Similarly, ABCB1 and ABCB4 efflux activity was observed in the developing gut, prior to the onset of feeding. This study reveals the early establishment of unique territories of small molecule transport during embryogenesis. A pattern of ABCC4/C5 expression is consistent with signaling functions during gut invagination and germ line development, while a later pattern of ABCB1/B4 and ABCG2 is consistent with roles in the embryonic gut. This work provides a conceptual framework with which to examine the function and evolution of SMT networks and to define the specific developmental pathways that drive the expression of these genes.
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Affiliation(s)
- Catherine S Schrankel
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego. 9500 Gilman Drive, La Jolla, CA, 92093-0202, USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego. 9500 Gilman Drive, La Jolla, CA, 92093-0202, USA.
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8
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Foster S, Oulhen N, Wessel G. A single cell RNA sequencing resource for early sea urchin development. Development 2020; 147:dev.191528. [PMID: 32816969 DOI: 10.1242/dev.191528] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/31/2020] [Indexed: 12/28/2022]
Abstract
Identifying cell states during development from their mRNA profiles provides insight into their gene regulatory network. Here, we leverage the sea urchin embryo for its well-established gene regulatory network to interrogate the embryo using single cell RNA sequencing. We tested eight developmental stages in Strongylocentrotus purpuratus, from the eight-cell stage to late in gastrulation. We used these datasets to parse out 22 major cell states of the embryo, focusing on key transition stages for cell type specification of each germ layer. Subclustering of these major embryonic domains revealed over 50 cell states with distinct transcript profiles. Furthermore, we identified the transcript profile of two cell states expressing germ cell factors, one we conclude represents the primordial germ cells and the other state is transiently present during gastrulation. We hypothesize that these cells of the Veg2 tier of the early embryo represent a lineage that converts to the germ line when the primordial germ cells are deleted. This broad resource will hopefully enable the community to identify other cell states and genes of interest to expose the underpinning of developmental mechanisms.
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Affiliation(s)
- Stephany Foster
- Department of Molecular and Cellular Biology, Division of BioMedicine, Brown University, Providence, RI 02912, USA
| | - Nathalie Oulhen
- Department of Molecular and Cellular Biology, Division of BioMedicine, Brown University, Providence, RI 02912, USA
| | - Gary Wessel
- Department of Molecular and Cellular Biology, Division of BioMedicine, Brown University, Providence, RI 02912, USA
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9
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Ettensohn CA. The gene regulatory control of sea urchin gastrulation. Mech Dev 2020; 162:103599. [PMID: 32119908 DOI: 10.1016/j.mod.2020.103599] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 02/07/2023]
Abstract
The cell behaviors associated with gastrulation in sea urchins have been well described. More recently, considerable progress has been made in elucidating gene regulatory networks (GRNs) that underlie the specification of early embryonic territories in this experimental model. This review integrates information from these two avenues of work. I discuss the principal cell movements that take place during sea urchin gastrulation, with an emphasis on molecular effectors of the movements, and summarize our current understanding of the gene regulatory circuitry upstream of those effectors. A case is made that GRN biology can provide a causal explanation of gastrulation, although additional analysis is needed at several levels of biological organization in order to provide a deeper understanding of this complex morphogenetic process.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA 15213, USA.
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10
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Hogan JD, Keenan JL, Luo L, Ibn-Salem J, Lamba A, Schatzberg D, Piacentino ML, Zuch DT, Core AB, Blumberg C, Timmermann B, Grau JH, Speranza E, Andrade-Navarro MA, Irie N, Poustka AJ, Bradham CA. The developmental transcriptome for Lytechinus variegatus exhibits temporally punctuated gene expression changes. Dev Biol 2019; 460:139-154. [PMID: 31816285 DOI: 10.1016/j.ydbio.2019.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 10/25/2022]
Abstract
Embryonic development is arguably the most complex process an organism undergoes during its lifetime, and understanding this complexity is best approached with a systems-level perspective. The sea urchin has become a highly valuable model organism for understanding developmental specification, morphogenesis, and evolution. As a non-chordate deuterostome, the sea urchin occupies an important evolutionary niche between protostomes and vertebrates. Lytechinus variegatus (Lv) is an Atlantic species that has been well studied, and which has provided important insights into signal transduction, patterning, and morphogenetic changes during embryonic and larval development. The Pacific species, Strongylocentrotus purpuratus (Sp), is another well-studied sea urchin, particularly for gene regulatory networks (GRNs) and cis-regulatory analyses. A well-annotated genome and transcriptome for Sp are available, but similar resources have not been developed for Lv. Here, we provide an analysis of the Lv transcriptome at 11 timepoints during embryonic and larval development. Temporal analysis suggests that the gene regulatory networks that underlie specification are well-conserved among sea urchin species. We show that the major transitions in variation of embryonic transcription divide the developmental time series into four distinct, temporally sequential phases. Our work shows that sea urchin development occurs via sequential intervals of relatively stable gene expression states that are punctuated by abrupt transitions.
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Affiliation(s)
- John D Hogan
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | | | - Lingqi Luo
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | - Jonas Ibn-Salem
- Evolution and Development Group, Max-Planck Institute for Molecular Genetics, Berlin, Germany; Faculty of Biology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Arjun Lamba
- Biology Department, Boston University, Boston, MA, USA
| | | | - Michael L Piacentino
- Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA
| | - Daniel T Zuch
- Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA
| | - Amanda B Core
- Biology Department, Boston University, Boston, MA, USA
| | | | - Bernd Timmermann
- Sequencing Core Facility, Max-Planck Institute for Molecular Genetics, Berlin, Germany
| | - José Horacio Grau
- Dahlem Centre for Genome Research and Medical Systems Biology, Environmental and Phylogenomics Group, Berlin, Germany; Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Emily Speranza
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | | | - Naoki Irie
- Department of Biological Sciences, University of Tokyo, Tokyo, Japan
| | - Albert J Poustka
- Evolution and Development Group, Max-Planck Institute for Molecular Genetics, Berlin, Germany; Dahlem Centre for Genome Research and Medical Systems Biology, Environmental and Phylogenomics Group, Berlin, Germany
| | - Cynthia A Bradham
- Program in Bioinformatics, Boston University, Boston, MA, USA; Biology Department, Boston University, Boston, MA, USA; Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA.
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11
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Oulhen N, Swartz SZ, Wang L, Wikramanayake A, Wessel GM. Distinct transcriptional regulation of Nanos2 in the germ line and soma by the Wnt and delta/notch pathways. Dev Biol 2019; 452:34-42. [PMID: 31075220 PMCID: PMC6848975 DOI: 10.1016/j.ydbio.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/19/2019] [Accepted: 04/21/2019] [Indexed: 12/23/2022]
Abstract
Specification of the primordial germ cells (PGCs) is essential for sexually reproducing animals. Although the mechanisms of PGC specification are diverse between organisms, the RNA binding protein Nanos is consistently required in the germ line in all species tested. How Nanos is selectively expressed in the germ line, however, remains largely elusive. We report that in sea urchin embryos, the early expression of Nanos2 in the PGCs requires the maternal Wnt pathway. During gastrulation, however, Nanos2 expression expands into adjacent somatic mesodermal cells and this secondary Nanos expression instead requires Delta/Notch signaling through the forkhead family member FoxY. Each of these transcriptional regulators were tested by chromatin immunoprecipitation analysis and found to directly interact with a DNA locus upstream of Nanos2. Given the conserved importance of Nanos in germ line specification, and the derived character of the micromeres and small micromeres in the sea urchin, we propose that the ancestral mechanism of Nanos2 expression in echinoderms was by induction in mesodermal cells during gastrulation.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, RI, 02912, USA
| | - S Zachary Swartz
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
| | - Lingyu Wang
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | | | - Gary M Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, RI, 02912, USA.
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12
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Foster S, Teo YV, Neretti N, Oulhen N, Wessel GM. Single cell RNA-seq in the sea urchin embryo show marked cell-type specificity in the Delta/Notch pathway. Mol Reprod Dev 2019; 86:931-934. [PMID: 31199038 DOI: 10.1002/mrd.23181] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/10/2019] [Accepted: 05/11/2019] [Indexed: 01/01/2023]
Abstract
Sea urchin embryos are excellent for in vivo functional studies because of their transparency and tractability in manipulation. They are also favorites for pharmacological approaches since they develop in an aquatic environment and addition of test substances is straightforward. A concern in many pharmacological tests though is the potential for pleiotropic effects that confound the conclusions drawn from the results. Precise cellular interpretations are often not feasible because the impact of the perturbant is not known. Here we use single-cell mRNA (messenger RNA) sequencing as a metric of cell types in the embryo and to determine the selectivity of two commonly used inhibitors, one each for the Wnt and the Delta-Notch pathways, on these nascent cell types. We identified 11 distinct cell types based on mRNA profiling, and that the cell lineages affected by Wnt and Delta/Notch inhibition were distinct from each other. These data support specificity and distinct effects of these signaling pathways in the embryo and illuminate how these conserved pathways selectively regulate cell lineages at a single cell level. Overall, we conclude that single cell RNA-seq analysis in this embryo is revealing of the cell types present during development, of the changes in the gene regulatory network resulting from inhibition of various signaling pathways, and of the selectivity of these pathways in influencing developmental trajectories.
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Affiliation(s)
- Stephany Foster
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Yee Voan Teo
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Nicola Neretti
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - Gary M Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
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13
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Buckley KM, Dong P, Cameron RA, Rast JP. Bacterial artificial chromosomes as recombinant reporter constructs to investigate gene expression and regulation in echinoderms. Brief Funct Genomics 2019; 17:362-371. [PMID: 29045542 DOI: 10.1093/bfgp/elx031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genome sequences contain all the necessary information-both coding and regulatory sequences-to construct an organism. The developmental process translates this genomic information into a three-dimensional form. One interpretation of this translation process can be described using gene regulatory network (GRN) models, which are maps of interactions among regulatory gene products in time and space. As high throughput investigations reveal increasing complexity within these GRNs, it becomes apparent that efficient methods are required to test the necessity and sufficiency of regulatory interactions. One of the most complete GRNs for early development has been described in the purple sea urchin, Strongylocentrotus purpuratus. This work has been facilitated by two resources: a well-annotated genome sequence and transgenes generated in bacterial artificial chromosome (BAC) constructs. BAC libraries played a central role in assembling the S. purpuratus genome sequence and continue to serve as platforms for generating reporter constructs for use in expression and regulatory analyses. Optically transparent echinoderm larvae are highly amenable to transgenic approaches and are therefore particularly well suited for experiments that rely on BAC-based reporter transgenes. Here, we discuss the experimental utility of BAC constructs in the context of understanding developmental processes in echinoderm embryos and larvae.
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Affiliation(s)
- Katherine M Buckley
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Ping Dong
- California Institute of Technology, California, USA
| | - R Andrew Cameron
- Beckman Institute Center for Computational Regulatory Genomics, California Institute for Technology, California, USA
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14
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Campanale JP, Hamdoun A, Wessel GM, Su YH, Oulhen N. Methods to label, isolate, and image sea urchin small micromeres, the primordial germ cells (PGCs). Methods Cell Biol 2019; 150:269-292. [PMID: 30777180 PMCID: PMC6487853 DOI: 10.1016/bs.mcb.2018.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Small micromeres of the sea urchin are believed to be primordial germ cells (PGCs), fated to give rise to sperm or eggs in the adult. Sea urchin PGCs are formed at the fifth cleavage, undergo one additional division during blastulation, and migrate to the coelomic pouches of the pluteus larva. The goal of this chapter is to detail classical and modern techniques used to analyze primordial germ cell specification, gene expression programs, and cell behaviors in fixed and live embryos. The transparency of the sea urchin embryo enables both live imaging techniques and in situ RNA hybridization and immunolabeling for a detailed molecular characterization of these cells. Four approaches are presented to highlight small micromeres with fluorescent molecules for analysis by live and fixed cell microscopy: (1) small molecule dye accumulation during cleavage and blastula stages, (2) primordial germ cell targeted RNA expression using the Nanos untranslated regions, (3) fusing genes of interest with a Nanos2 targeting peptide, and (4) EdU and BrdU labeling. Applications of the live labeling techniques are discussed, including sorting by fluorescence-activated cell sorting for transcriptomic analysis, and, methods to image small micromere behavior in whole and dissociated embryos by live confocal microscopy. Finally, summary table of antibody and RNA probes as well as small molecule dyes to label small micromeres at a variety of developmental stages is provided.
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Affiliation(s)
- Joseph P Campanale
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
| | - Amro Hamdoun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
| | - Gary M Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, United States
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, United States
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15
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Ono H, Koop D, Holland LZ. Nodal and Hedgehog synergize in gill slit formation during development of the cephalochordate Branchiostoma floridae. Development 2018; 145:dev.162586. [PMID: 29980563 DOI: 10.1242/dev.162586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 06/14/2018] [Indexed: 12/16/2022]
Abstract
The larval pharynx of the cephalochordate Branchiostoma (amphioxus) is asymmetrical. The mouth is on the left, and endostyle and gill slits are on the right. At the neurula, Nodal and Hedgehog (Hh) expression becomes restricted to the left. To dissect their respective roles in gill slit formation, we inhibited each pathway separately for 20 min at intervals during the neurula stage, before gill slits penetrate, and monitored the effects on morphology and expression of pharyngeal markers. The results pinpoint the short interval spanning the gastrula/neurula transition as the critical period for specification and positioning of future gill slits. Thus, reduced Nodal signaling shifts the gill slits ventrally, skews the pharyngeal domains of Hh, Pax1/9, Pax2/5/8, Six1/2 and IrxC towards the left, and reduces Hh and Tbx1/10 expression in endoderm and mesoderm, respectively. Nodal auto-regulates. Decreased Hh signaling does not affect gill slit positions or Hh or Nodal expression, but it does reduce the domain of Gli, the Hh target, in the pharyngeal endoderm. Thus, during the neurula stage, Nodal and Hh cooperate in gill slit development - Hh mediates gill slit formation and Nodal establishes their left-right position.
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Affiliation(s)
- Hiroki Ono
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202, USA
| | - Demian Koop
- Discipline of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Linda Z Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202, USA
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16
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Favarolo MB, López SL. Notch signaling in the division of germ layers in bilaterian embryos. Mech Dev 2018; 154:122-144. [PMID: 29940277 DOI: 10.1016/j.mod.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/08/2018] [Accepted: 06/18/2018] [Indexed: 01/09/2023]
Abstract
Bilaterian embryos are triploblastic organisms which develop three complete germ layers (ectoderm, mesoderm, and endoderm). While the ectoderm develops mainly from the animal hemisphere, there is diversity in the location from where the endoderm and the mesoderm arise in relation to the animal-vegetal axis, ranging from endoderm being specified between the ectoderm and mesoderm in echinoderms, and the mesoderm being specified between the ectoderm and the endoderm in vertebrates. A common feature is that part of the mesoderm segregates from an ancient bipotential endomesodermal domain. The process of segregation is noisy during the initial steps but it is gradually refined. In this review, we discuss the role of the Notch pathway in the establishment and refinement of boundaries between germ layers in bilaterians, with special focus on its interaction with the Wnt/β-catenin pathway.
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Affiliation(s)
- María Belén Favarolo
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina
| | - Silvia L López
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires, Argentina.
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17
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Cui M, Lin CY, Su YH. Recent advances in functional perturbation and genome editing techniques in studying sea urchin development. Brief Funct Genomics 2018; 16:309-318. [PMID: 28605407 DOI: 10.1093/bfgp/elx011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Studies on the gene regulatory networks (GRNs) of sea urchin embryos have provided a basic understanding of the molecular mechanisms controlling animal development. The causal links in GRNs have been verified experimentally through perturbation of gene functions. Microinjection of antisense morpholino oligonucleotides (MOs) into the egg is the most widely used approach for gene knockdown in sea urchin embryos. The modification of MOs into a membrane-permeable form (vivo-MOs) has allowed gene knockdown at later developmental stages. Recent advances in genome editing tools, such as zinc-finger nucleases, transcription activator-like effector-based nucleases and the clustered regularly interspaced short palindromic repeat/clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR/Cas9) system, have provided methods for gene knockout in sea urchins. Here, we review the use of vivo-MOs and genome editing tools in sea urchin studies since the publication of its genome in 2006. Various applications of the CRISPR/Cas9 system and their potential in studying sea urchin development are also discussed. These new tools will provide more sophisticated experimental methods for studying sea urchin development.
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18
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Notch-mediated lateral inhibition is an evolutionarily conserved mechanism patterning the ectoderm in echinoids. Dev Genes Evol 2017; 228:1-11. [PMID: 29249002 DOI: 10.1007/s00427-017-0599-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/08/2017] [Indexed: 10/18/2022]
Abstract
Notch signaling is a crucial cog in early development of euechinoid sea urchins, specifying both non-skeletogenic mesodermal lineages and serotonergic neurons in the apical neuroectoderm. Here, the spatial distributions and function of delta, gcm, and hesc, three genes critical to these processes in euechinoids, are examined in the distantly related cidaroid sea urchin Eucidaris tribuloides. Spatial distribution and experimental perturbation of delta and hesc suggest that the function of Notch signaling in ectodermal patterning in early development of E. tr ibuloides is consistent with canonical lateral inhibition. Delta transcripts were observed in t he archenteron, apical ectoderm, and lateral ectoderm in gastrulating e mbryos of E. tribuloides. Perturbation of Notch signaling by either delta morpholino or treatment of DAPT downregulated hesc and upregulated delta and gcm, resulting in ectopic expression of delta and gcm. Similarly, hesc perturbation mirrored the effects of delta perturbation. Interestingly, perturbation of delta or hesc resulted in more cells expressing gcm and supernumerary pigment cells, suggesting that pigment cell proliferation is regulated by Notch in E. tribuloides. These results are consistent with an evolutionary scenario whereby, in the echinoid ancestor, Notch signaling was deployed in the ectoderm to specify neurogenic progenitors and controlled pigment cell proliferation in the dorsal ectoderm.
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19
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Schrankel CS, Solek CM, Buckley KM, Anderson MK, Rast JP. A conserved alternative form of the purple sea urchin HEB/E2-2/E2A transcription factor mediates a switch in E-protein regulatory state in differentiating immune cells. Dev Biol 2016; 416:149-161. [PMID: 27265865 DOI: 10.1016/j.ydbio.2016.05.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 12/11/2022]
Abstract
E-proteins are basic helix-loop-helix (bHLH) transcription factors with essential roles in animal development. In mammals, these are encoded by three loci: E2-2 (ITF-2/ME2/SEF2/TCF4), E2A (TCF3), and HEB (ME1/REB/TCF12). The HEB and E2-2 paralogs are expressed as alternative (Alt) isoforms with distinct N-terminal sequences encoded by unique exons under separate regulatory control. Expression of these alternative transcripts is restricted relative to the longer (Can) forms, suggesting distinct regulatory roles, although the functions of the Alt proteins remain poorly understood. Here, we characterize the single sea urchin E-protein ortholog (SpE-protein). The organization of the SpE-protein gene closely resembles that of the extended HEB/E2-2 vertebrate loci, including a transcript that initiates at a homologous alternative transcription start site (SpE-Alt). The existence of an Alt form in the sea urchin indicates that this feature predates the emergence of the vertebrates. We present additional evidence indicating that this transcript was present in the common bilaterian ancestor. In contrast to the widely expressed canonical form (SpE-Can), SpE-Alt expression is tightly restricted. SpE-Alt is expressed in two phases: first in aboral non-skeletogenic mesenchyme (NSM) cells and then in oral NSM cells preceding their differentiation and ingression into the blastocoel. Derivatives of these cells mediate immune response in the larval stage. Inhibition of SpE-Alt activity interferes with these events. Notably, although the two isoforms are initially co-expressed, as these cells differentiate, SpE-Can is excluded from the SpE-Alt(+) cell population. This mutually exclusive expression is dependent on SpE-Alt function, which reveals a previously undescribed negative regulatory linkage between the two E-protein forms. Collectively, these findings reorient our understanding of the evolution of this transcription factor family and highlight fundamental properties of E-protein biology.
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Affiliation(s)
- Catherine S Schrankel
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Cynthia M Solek
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Katherine M Buckley
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Michele K Anderson
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Jonathan P Rast
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Immunology, University of Toronto, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
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20
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Perillo M, Wang YJ, Leach SD, Arnone MI. A pancreatic exocrine-like cell regulatory circuit operating in the upper stomach of the sea urchin Strongylocentrotus purpuratus larva. BMC Evol Biol 2016; 16:117. [PMID: 27230062 PMCID: PMC4880809 DOI: 10.1186/s12862-016-0686-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/12/2016] [Indexed: 12/22/2022] Open
Abstract
Background Digestive cells are present in all metazoans and provide the energy necessary for the whole organism. Pancreatic exocrine cells are a unique vertebrate cell type involved in extracellular digestion of a wide range of nutrients. Although the organization and regulation of this cell type is intensively studied in vertebrates, its evolutionary history is still unknown. In order to understand which are the elements that define the pancreatic exocrine phenotype, we have analyzed the expression of genes that contribute to specification and function of this cell-type in an early branching deuterostome, the sea urchin Strongylocentrotus purpuratus. Results We defined the spatial and temporal expression of sea urchin orthologs of pancreatic exocrine genes and described a unique population of cells clustered in the upper stomach of the sea urchin embryo where exocrine markers are co-expressed. We used a combination of perturbation analysis, drug and feeding experiments and found that in these cells of the sea urchin embryo gene expression and gene regulatory interactions resemble that of bona fide pancreatic exocrine cells. We show that the sea urchin Ptf1a, a key transcriptional activator of digestive enzymes in pancreatic exocrine cells, can substitute for its vertebrate ortholog in activating downstream genes. Conclusions Collectively, our study is the first to show with molecular tools that defining features of a vertebrate cell-type, the pancreatic exocrine cell, are shared by a non-vertebrate deuterostome. Our results indicate that the functional cell-type unit of the vertebrate pancreas may evolutionarily predate the emergence of the pancreas as a discrete organ. From an evolutionary perspective, these results encourage to further explore the homologs of other vertebrate cell-types in traditional or newly emerging deuterostome systems. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0686-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margherita Perillo
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, 80121, Italy.,Present address: Department of Biology, Boston College, Chestnut Hill, MA, USA
| | - Yue Julia Wang
- Department of Surgery and the McKusick Nathans Institute for Genetic Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Steven D Leach
- Department of Surgery and the McKusick Nathans Institute for Genetic Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Maria Ina Arnone
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, 80121, Italy.
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21
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Israel JW, Martik ML, Byrne M, Raff EC, Raff RA, McClay DR, Wray GA. Comparative Developmental Transcriptomics Reveals Rewiring of a Highly Conserved Gene Regulatory Network during a Major Life History Switch in the Sea Urchin Genus Heliocidaris. PLoS Biol 2016; 14:e1002391. [PMID: 26943850 PMCID: PMC4778923 DOI: 10.1371/journal.pbio.1002391] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/26/2016] [Indexed: 01/08/2023] Open
Abstract
The ecologically significant shift in developmental strategy from planktotrophic (feeding) to lecithotrophic (nonfeeding) development in the sea urchin genus Heliocidaris is one of the most comprehensively studied life history transitions in any animal. Although the evolution of lecithotrophy involved substantial changes to larval development and morphology, it is not known to what extent changes in gene expression underlie the developmental differences between species, nor do we understand how these changes evolved within the context of the well-defined gene regulatory network (GRN) underlying sea urchin development. To address these questions, we used RNA-seq to measure expression dynamics across development in three species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph H. tuberculata, and an outgroup planktotroph Lytechinus variegatus. Using well-established statistical methods, we developed a novel framework for identifying, quantifying, and polarizing evolutionary changes in gene expression profiles across the transcriptome and within the GRN. We found that major changes in gene expression profiles were more numerous during the evolution of lecithotrophy than during the persistence of planktotrophy, and that genes with derived expression profiles in the lecithotroph displayed specific characteristics as a group that are consistent with the dramatically altered developmental program in this species. Compared to the transcriptome, changes in gene expression profiles within the GRN were even more pronounced in the lecithotroph. We found evidence for conservation and likely divergence of particular GRN regulatory interactions in the lecithotroph, as well as significant changes in the expression of genes with known roles in larval skeletogenesis. We further use coexpression analysis to identify genes of unknown function that may contribute to both conserved and derived developmental traits between species. Collectively, our results indicate that distinct evolutionary processes operate on gene expression during periods of life history conservation and periods of life history divergence, and that this contrast is even more pronounced within the GRN than across the transcriptome as a whole.
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Affiliation(s)
- Jennifer W. Israel
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Megan L. Martik
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Maria Byrne
- Schools of Medical and Biological Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Elizabeth C. Raff
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Rudolf A. Raff
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - David R. McClay
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Gregory A. Wray
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
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22
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Martik ML, Lyons DC, McClay DR. Developmental gene regulatory networks in sea urchins and what we can learn from them. F1000Res 2016; 5. [PMID: 26962438 PMCID: PMC4765714 DOI: 10.12688/f1000research.7381.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/19/2016] [Indexed: 12/21/2022] Open
Abstract
Sea urchin embryos begin zygotic transcription shortly after the egg is fertilized. Throughout the cleavage stages a series of transcription factors are activated and, along with signaling through a number of pathways, at least 15 different cell types are specified by the beginning of gastrulation. Experimentally, perturbation of contributing transcription factors, signals and receptors and their molecular consequences enabled the assembly of an extensive gene regulatory network model. That effort, pioneered and led by Eric Davidson and his laboratory, with many additional insights provided by other laboratories, provided the sea urchin community with a valuable resource. Here we describe the approaches used to enable the assembly of an advanced gene regulatory network model describing molecular diversification during early development. We then provide examples to show how a relatively advanced authenticated network can be used as a tool for discovery of how diverse developmental mechanisms are controlled and work.
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Affiliation(s)
- Megan L Martik
- Biology Department, Duke University, Durham, North Carolina, 27708, USA
| | - Deirdre C Lyons
- Biology Department, Duke University, Durham, North Carolina, 27708, USA
| | - David R McClay
- Biology Department, Duke University, Durham, North Carolina, 27708, USA
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23
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Warner JF, Miranda EL, McClay DR. Contribution of hedgehog signaling to the establishment of left-right asymmetry in the sea urchin. Dev Biol 2016; 411:314-324. [PMID: 26872875 DOI: 10.1016/j.ydbio.2016.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 02/06/2016] [Accepted: 02/08/2016] [Indexed: 01/22/2023]
Abstract
Most bilaterians exhibit a left-right asymmetric distribution of their internal organs. The sea urchin larva is notable in this regard since most adult structures are generated from left sided embryonic structures. The gene regulatory network governing this larval asymmetry is still a work in progress but involves several conserved signaling pathways including Nodal, and BMP. Here we provide a comprehensive analysis of Hedgehog signaling and it's contribution to left-right asymmetry. We report that Hh signaling plays a conserved role to regulate late asymmetric expression of Nodal and that this regulation occurs after Nodal breaks left-right symmetry in the mesoderm. Thus, while Hh functions to maintain late Nodal expression, the molecular asymmetry of the future coelomic pouches is locked in. Furthermore we report that cilia play a role only insofar as to transduce Hh signaling and do not have an independent effect on the asymmetry of the mesoderm. From this, we are able to construct a more complete regulatory network governing the establishment of left-right asymmetry in the sea urchin.
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Affiliation(s)
- Jacob F Warner
- Duke University Department of Biology, Durham, NC, United States
| | - Esther L Miranda
- Duke University Department of Biology, Durham, NC, United States
| | - David R McClay
- Duke University Department of Biology, Durham, NC, United States.
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Abstract
With few exceptions, all animals acquire the ability to produce eggs or sperm at some point in their life cycle. Despite this near-universal requirement for sexual reproduction, there exists an incredible diversity in germ line development. For example, animals exhibit a vast range of differences in the timing at which the germ line, which retains reproductive potential, separates from the soma, or terminally differentiated, nonreproductive cells. This separation may occur during embryonic development, after gastrulation, or even in adults, depending on the organism. The molecular mechanisms of germ line segregation are also highly diverse, and intimately intertwined with the overall transition from a fertilized egg to an embryo. The earliest embryonic stages of many species are largely controlled by maternally supplied factors. Later in development, patterning control shifts to the embryonic genome and, concomitantly with this transition, the maternally supplied factors are broadly degraded. This chapter attempts to integrate these processes--germ line segregation, and how the divergence of germ line and soma may utilize the egg to embryo transitions differently. In some embryos, this difference is subtle or maybe lacking altogether, whereas in other embryos, this difference in utilization may be a key step in the divergence of the two lineages. Here, we will focus our discussion on the echinoderms, and in particular the sea urchins, in which recent studies have provided mechanistic understanding in germ line determination. We propose that the germ line in sea urchins requires an acquisition of maternal factors from the egg and, when compared to other members of the taxon, this appears to be a derived mechanism. The acquisition is early--at the 32-cell stage--and involves active protection of maternal mRNAs, which are instead degraded in somatic cells with the maternal-to-embryonic transition. We collectively refer to this model as the Time Capsule method for germ line determination.
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Affiliation(s)
- S Zachary Swartz
- Department of Molecular and Cellular Biology, Brown University, Providence, Rhode Island, USA
| | - Gary M Wessel
- Department of Molecular and Cellular Biology, Brown University, Providence, Rhode Island, USA.
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25
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Andrikou C, Pai CY, Su YH, Arnone MI. Logics and properties of a genetic regulatory program that drives embryonic muscle development in an echinoderm. eLife 2015. [PMID: 26218224 PMCID: PMC4549668 DOI: 10.7554/elife.07343] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Evolutionary origin of muscle is a central question when discussing mesoderm evolution. Developmental mechanisms underlying somatic muscle development have mostly been studied in vertebrates and fly where multiple signals and hierarchic genetic regulatory cascades selectively specify myoblasts from a pool of naive mesodermal progenitors. However, due to the increased organismic complexity and distant phylogenetic position of the two systems, a general mechanistic understanding of myogenesis is still lacking. In this study, we propose a gene regulatory network (GRN) model that promotes myogenesis in the sea urchin embryo, an early branching deuterostome. A fibroblast growth factor signaling and four Forkhead transcription factors consist the central part of our model and appear to orchestrate the myogenic process. The topological properties of the network reveal dense gene interwiring and a multilevel transcriptional regulation of conserved and novel myogenic genes. Finally, the comparison of the myogenic network architecture among different animal groups highlights the evolutionary plasticity of developmental GRNs. DOI:http://dx.doi.org/10.7554/eLife.07343.001 Muscles, bones, and blood vessels all develop from a tissue called the mesoderm, which forms early on in the development of an embryo. Networks of genes control which parts of the mesoderm transform into different cell types. The gene networks that control the development of muscle cells from the mesoderm have so far been investigated in flies and several species of animals with backbones. However, these species are complex, which makes it difficult to work out the general principles that control muscle cell development. Sea urchins are often studied in developmental biology as they have many of the same genes as more complex animals, but are much simpler and easier to study in the laboratory. Andrikou et al. therefore investigated the ‘gene regulatory network’ that controls muscle development in sea urchins. This revealed that proteins called Forkhead transcription factors and a process called FGF signaling are crucial for controlling muscle development in sea urchins. These are also important factors for developing muscles in other animals. Andrikou et al. then produced models that show the interactions between the genes that control muscle formation at three different stages of embryonic development. These models reveal several important features of the muscle development gene regulatory network. For example, the network is robust: if one gene fails, the network is connected in a way that allows it to still make muscle. This also allows the network to adapt and evolve without losing the ability to perform any of its existing roles. Comparing the gene regulatory network that controls muscle development in sea urchins with the networks found in other animals showed that many of the same genes are used across different species, but are connected into different network structures. Investigating the similarities and differences of the regulatory networks in different species could help us to understand how muscles have evolved and could ultimately lead to a better understanding of the causes of developmental diseases. DOI:http://dx.doi.org/10.7554/eLife.07343.002
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Affiliation(s)
- Carmen Andrikou
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - Chih-Yu Pai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Maria Ina Arnone
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
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Yajima M, Wessel GM. Essential elements for translation: the germline factor Vasa functions broadly in somatic cells. Development 2015; 142:1960-70. [PMID: 25977366 PMCID: PMC4460737 DOI: 10.1242/dev.118448] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 03/30/2015] [Indexed: 01/23/2023]
Abstract
Vasa is a conserved RNA-helicase found in the germ lines of all metazoans tested. Whereas Vasa presence is often indicated as a metric for germline determination in animals, it is also expressed in stem cells of diverse origin. Recent research suggests, however, that Vasa has a much broader function, including a significant role in cell cycle regulation. Results herein indicate that Vasa is utilized widely, and often induced transiently, during development in diverse somatic cells and adult precursor tissues. We identified that Vasa in the sea urchin is essential for: (1) general mRNA translation during embryogenesis, (2) developmental re-programming upon manipulations to the embryo and (3) larval wound healing. We also learned that Vasa interacted with mRNAs in the perinuclear area and at the spindle in an Importin-dependent manner during cell cycle progression. These results suggest that, when present, Vasa functions are essential to contributing to developmental regulation.
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Affiliation(s)
- Mamiko Yajima
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | - Gary M Wessel
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
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Wessel GM, Brayboy L, Fresques T, Gustafson EA, Oulhen N, Ramos I, Reich A, Swartz SZ, Yajima M, Zazueta V. The biology of the germ line in echinoderms. Mol Reprod Dev 2014; 81:679-711. [PMID: 23900765 PMCID: PMC4102677 DOI: 10.1002/mrd.22223] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 07/23/2013] [Indexed: 12/16/2022]
Abstract
The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ-line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed.
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Affiliation(s)
- Gary M. Wessel
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Lynae Brayboy
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Tara Fresques
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Eric A. Gustafson
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Nathalie Oulhen
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Isabela Ramos
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Adrian Reich
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - S. Zachary Swartz
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Mamiko Yajima
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Vanessa Zazueta
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island
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Affiliation(s)
- Jacob F. Warner
- Department of Biology; Duke University; Durham North Carolina
| | - David R. McClay
- Department of Biology; Duke University; Durham North Carolina
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Oulhen N, Wessel GM. Every which way--nanos gene regulation in echinoderms. Genesis 2014; 52:279-86. [PMID: 24376110 DOI: 10.1002/dvg.22737] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 12/16/2013] [Indexed: 12/12/2022]
Abstract
Nanos is an essential factor of germ line success in all animals tested. This gene encodes a Zn-finger RNA-binding protein that in complex with its partner pumilio binds to and changes the fate of several known transcripts. We summarize here the documented functions of Nanos in several key organisms, and then emphasize echinoderms as a working model for how nanos expression is regulated. Nanos presence outside of the target cells is often detrimental to the animal, and in sea urchins, nanos expression appears to be regulated at every step of transcription, and post-transcriptional activity, making this gene product exciting, every which way.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
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Su YH. Telling left from right: Left-right asymmetric controls in sea urchins. Genesis 2014; 52:269-78. [DOI: 10.1002/dvg.22739] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/20/2013] [Accepted: 12/31/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Yi-Hsien Su
- Institute of Cellular and Organismic Biology; Academia Sinica; Nankang Taipei Taiwan
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Andrikou C, Iovene E, Rizzo F, Oliveri P, Arnone MI. Myogenesis in the sea urchin embryo: the molecular fingerprint of the myoblast precursors. EvoDevo 2013; 4:33. [PMID: 24295205 PMCID: PMC4175510 DOI: 10.1186/2041-9139-4-33] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/02/2013] [Indexed: 01/01/2023] Open
Abstract
Background In sea urchin larvae the circumesophageal fibers form a prominent muscle system of mesodermal origin. Although the morphology and later development of this muscle system has been well-described, little is known about the molecular signature of these cells or their precise origin in the early embryo. As an invertebrate deuterostome that is more closely related to the vertebrates than other commonly used model systems in myogenesis, the sea urchin fills an important phylogenetic gap and provides a unique perspective on the evolution of muscle cell development. Results Here, we present a comprehensive description of the development of the sea urchin larval circumesophageal muscle lineage beginning with its mesodermal origin using high-resolution localization of the expression of several myogenic transcriptional regulators and differentiation genes. A few myoblasts are bilaterally distributed at the oral vegetal side of the tip of the archenteron and first appear at the late gastrula stage. The expression of the differentiation genes Myosin Heavy Chain, Tropomyosin I and II, as well as the regulatory genes MyoD2, FoxF, FoxC, FoxL1, Myocardin, Twist, and Tbx6 uniquely identify these cells. Interestingly, evolutionarily conserved myogenic factors such as Mef2, MyoR and Six1/2 are not expressed in sea urchin myoblasts but are found in other mesodermal domains of the tip of the archenteron. The regulatory states of these domains were characterized in detail. Moreover, using a combinatorial analysis of gene expression we followed the development of the FoxF/FoxC positive cells from the onset of expression to the end of gastrulation. Our data allowed us to build a complete map of the Non-Skeletogenic Mesoderm at the very early gastrula stage, in which specific molecular signatures identify the precursors of different cell types. Among them, a small group of cells within the FoxY domain, which also express FoxC and SoxE, have been identified as plausible myoblast precursors. Together, these data support a very early gastrula stage segregation of the myogenic lineage. Conclusions From this analysis, we are able to precisely define the regulatory and differentiation signatures of the circumesophageal muscle in the sea urchin embryo. Our findings have important implications in understanding the evolution of development of the muscle cell lineage at the molecular level. The data presented here suggest a high level of conservation of the myogenic specification mechanisms across wide phylogenetic distances, but also reveal clear cases of gene cooption.
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Affiliation(s)
| | | | | | | | - Maria Ina Arnone
- Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Napoli 80121, Italy.
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