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Kawamura K, Satoh N. Embryonic Development of the Gastrodermis in the Coral Acropora tenuis. Zoolog Sci 2024; 41:496-508. [PMID: 39636132 DOI: 10.2108/zs240032] [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: 04/23/2024] [Accepted: 08/18/2024] [Indexed: 12/07/2024]
Abstract
Due to limited spawning seasons, embryogenesis of corals has not fully been studied and the embryonic origin of gastrodermis remains uncertain in Acropora. We herein examined how embryonic endodermal cells develop into the gastrodermis and mesentery of polyps in Acropora tenuis. In juvenile polyps, the gastrodermis invaginates to form mesenteries, both of which were stained with rhodamine-phalloidin, an anti-myocyte-specific enhancer factor 2 (anti-AtMef2) antibody, and an anti-lipoxygenase homology domain-containing protein 1 (anti-AtLoxhd1) antibody. Rhoda-mine-phalloidin staining was traced back to the endodermal cells of 60-85 hpf 'pear'-stage embryos through the larval stage. AtMef2 appeared in the blastomeres of a 12-hpf 'prawnchip'-stage embryo that was a variant U-shaped blastula with a narrow blastocoel. AtMef2 temporarily disappeared from the nuclei of 28-hpf 'donut'-stage embryos and reappeared in the endodermal cells of 40-hpf early 'pear'-stage embryos, suggesting a transition from maternal to zygotic expression of Mef2. The blastopore closed without the invagination of blastomeres. The gastrocoel collapsed and the Mef2-positive endoderm was dissociated into single cells in the well-developed blastocoel filled with yolk cells. The mesoglea appeared in the yolk cell layer. AtLoxhd1 was traced back to the endodermal cells of 'pear'-stage embryos. In 11-dpf larvae, Loxhd1-positive endodermal cells elongated in the vicinity of the mesoglea to adhere to each other and form the gastroderm epithelium in larvae. Therefore, in this coral, the inner wall of U-shaped early embryos is the cellular origin of the gastrodermis. Inner wall-derived endodermal cells move independently toward the mesoglea, where cell-cell adhesion occurs to establish the gastrodermis.
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Affiliation(s)
- Kaz Kawamura
- Department of Applied Science, Kochi University, Kochi 780-8520, Japan,
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan,
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2
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Thiery JP, Sheng G, Shu X, Runyan R. How studies in developmental epithelial-mesenchymal transition and mesenchymal-epithelial transition inspired new research paradigms in biomedicine. Development 2024; 151:dev200128. [PMID: 38300897 DOI: 10.1242/dev.200128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Epithelial-mesenchymal transition (EMT) and its reverse mechanism, mesenchymal-epithelial transition (MET), are evolutionarily conserved mechanisms initially identified in studies of early metazoan development. EMT may even have been established in choanoflagellates, the closest unicellular relative of Metazoa. These crucial morphological transitions operate during body plan formation and subsequently in organogenesis. These findings have prompted an increasing number of investigators in biomedicine to assess the importance of such mechanisms that drive epithelial cell plasticity in multiple diseases associated with congenital disabilities and fibrosis, and, most importantly, in the progression of carcinoma. EMT and MET also play crucial roles in regenerative medicine, notably by contributing epigenetic changes in somatic cells to initiate reprogramming into stem cells and their subsequent differentiation into distinct lineages.
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Affiliation(s)
| | - Guojun Sheng
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto 860-0811, Japan
| | - Xiaodong Shu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Raymond Runyan
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
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3
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Massri AJ, McDonald B, Wray GA, McClay DR. Feedback circuits are numerous in embryonic gene regulatory networks and offer a stabilizing influence on evolution of those networks. EvoDevo 2023; 14:10. [PMID: 37322563 DOI: 10.1186/s13227-023-00214-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 06/06/2023] [Indexed: 06/17/2023] Open
Abstract
The developmental gene regulatory networks (dGRNs) of two sea urchin species, Lytechinus variegatus (Lv) and Strongylocentrotus purpuratus (Sp), have remained remarkably similar despite about 50 million years since a common ancestor. Hundreds of parallel experimental perturbations of transcription factors with similar outcomes support this conclusion. A recent scRNA-seq analysis suggested that the earliest expression of several genes within the dGRNs differs between Lv and Sp. Here, we present a careful reanalysis of the dGRNs in these two species, paying close attention to timing of first expression. We find that initial expression of genes critical for cell fate specification occurs during several compressed time periods in both species. Previously unrecognized feedback circuits are inferred from the temporally corrected dGRNs. Although many of these feedbacks differ in location within the respective GRNs, the overall number is similar between species. We identify several prominent differences in timing of first expression for key developmental regulatory genes; comparison with a third species indicates that these heterochronies likely originated in an unbiased manner with respect to embryonic cell lineage and evolutionary branch. Together, these results suggest that interactions can evolve even within highly conserved dGRNs and that feedback circuits may buffer the effects of heterochronies in the expression of key regulatory genes.
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Affiliation(s)
| | - Brennan McDonald
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA
| | - Gregory A Wray
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA
| | - David R McClay
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA.
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Taylor E, Wynen H, Heyland A. Thyroid hormone membrane receptor binding and transcriptional regulation in the sea urchin Strongylocentrotus purpuratus. Front Endocrinol (Lausanne) 2023; 14:1195733. [PMID: 37305042 PMCID: PMC10250714 DOI: 10.3389/fendo.2023.1195733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/10/2023] [Indexed: 06/13/2023] Open
Abstract
Thyroid hormones (THs) are small amino acid derived signaling molecules with broad physiological and developmental functions in animals. Specifically, their function in metamorphic development, ion regulation, angiogenesis and many others have been studied in detail in mammals and some other vertebrates. Despite extensive reports showing pharmacological responses of invertebrate species to THs, little is known about TH signaling mechanisms outside of vertebrates. Previous work in sea urchins suggests that non-genomic mechanisms are activated by TH ligands. Here we show that several THs bind to sea urchin (Strongylocentrotus purpuratus) cell membrane extracts and are displaced by ligands of RGD-binding integrins. A transcriptional analysis across sea urchin developmental stages shows activation of genomic and non-genomic pathways in response to TH exposure, suggesting that both pathways are activated by THs in sea urchin embryos and larvae. We also provide evidence associating TH regulation of gene expression with TH response elements in the genome. In ontogeny, we found more differentially expressed genes in older larvae compared to gastrula stages. In contrast to gastrula stages, the acceleration of skeletogenesis by thyroxine in older larvae is not fully inhibited by competitive ligands or inhibitors of the integrin membrane receptor pathway, suggesting that THs likely activate multiple pathways. Our data confirms a signaling function of THs in sea urchin development and suggests that both genomic and non-genomic mechanisms play a role, with genomic signaling being more prominent during later stages of larval development.
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Affiliation(s)
| | | | - Andreas Heyland
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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5
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Davidson PL, Guo H, Swart JS, Massri AJ, Edgar A, Wang L, Berrio A, Devens HR, Koop D, Cisternas P, Zhang H, Zhang Y, Byrne M, Fan G, Wray GA. Recent reconfiguration of an ancient developmental gene regulatory network in Heliocidaris sea urchins. Nat Ecol Evol 2022; 6:1907-1920. [PMID: 36266460 DOI: 10.1038/s41559-022-01906-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 09/12/2022] [Indexed: 12/15/2022]
Abstract
Changes in developmental gene regulatory networks (dGRNs) underlie much of the diversity of life, but the evolutionary mechanisms that operate on regulatory interactions remain poorly understood. Closely related species with extreme phenotypic divergence provide a valuable window into the genetic and molecular basis for changes in dGRNs and their relationship to adaptive changes in organismal traits. Here we analyse genomes, epigenomes and transcriptomes during early development in two Heliocidaris sea urchin species that exhibit highly divergent life histories and in an outgroup species. Positive selection and chromatin accessibility modifications within putative regulatory elements are enriched on the branch leading to the derived life history, particularly near dGRN genes. Single-cell transcriptomes reveal a dramatic delay in cell fate specification in the derived state, which also has far fewer open chromatin regions, especially near conserved cell fate specification genes. Experimentally perturbing key transcription factors reveals profound evolutionary changes to early embryonic patterning events, disrupting regulatory interactions previously conserved for ~225 million years. These results demonstrate that natural selection can rapidly reshape developmental gene expression on a broad scale when selective regimes abruptly change. More broadly, even highly conserved dGRNs and patterning mechanisms in the early embryo remain evolvable under appropriate ecological circumstances.
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Affiliation(s)
| | - Haobing Guo
- BGI-Qingdao, BGI-Shenzhen, Qingdao, China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, China
| | - Jane S Swart
- Department of Biology, Duke University, Durham, NC, USA
| | | | - Allison Edgar
- Department of Biology, Duke University, Durham, NC, USA
| | - Lingyu Wang
- Department of Biology, Duke University, Durham, NC, USA
| | | | | | - Demian Koop
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Paula Cisternas
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - He Zhang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, China
| | - Yaolei Zhang
- BGI-Qingdao, BGI-Shenzhen, Qingdao, China
- Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao, China
| | - Maria Byrne
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Guangyi Fan
- BGI-Qingdao, BGI-Shenzhen, Qingdao, China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, China
| | - Gregory A Wray
- Department of Biology, Duke University, Durham, NC, USA.
- Center for Genomic and Computational Biology, Duke University, Durham, NC, USA.
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Ettensohn CA, Guerrero-Santoro J, Khor JM. Lessons from a transcription factor: Alx1 provides insights into gene regulatory networks, cellular reprogramming, and cell type evolution. Curr Top Dev Biol 2022; 146:113-148. [PMID: 35152981 DOI: 10.1016/bs.ctdb.2021.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The skeleton-forming cells of sea urchins and other echinoderms have been studied by developmental biologists as models of cell specification and morphogenesis for many decades. The gene regulatory network (GRN) deployed in the embryonic skeletogenic cells of euechinoid sea urchins is one of the best understood in any developing animal. Recent comparative studies have leveraged the information contained in this GRN, bringing renewed attention to the diverse patterns of skeletogenesis within the phylum and the evolutionary basis for this diversity. The homeodomain-containing transcription factor, Alx1, was originally shown to be a core component of the skeletogenic GRN of the sea urchin embryo. Alx1 has since been found to be key regulator of skeletal cell identity throughout the phylum. As such, Alx1 is currently serving as a lens through which multiple developmental processes are being investigated. These include not only GRN organization and evolution, but also cell reprogramming, cell type evolution, and the gene regulatory control of morphogenesis. This review summarizes our current state of knowledge concerning Alx1 and highlights the insights it is yielding into these important developmental and evolutionary processes.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States.
| | | | - Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
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7
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Abstract
Larvae of sea urchins have a population of conspicuous pigmented cells embedded in the outer surface epithelium. Pigment cells are a distinct mesodermal lineage that gives rise to a key component of the larval immune system. During cleavage, signaling from adjacent cells influences a small crescent of cells to initiate a network of genetic interactions that prepare the cells for morphogenesis and specializes them as immunocytes. The cells become active during gastrulation, detach from the epithelium, migrate through the blastocoel, and insert into the ectoderm where they complete their differentiation. Studies of pigment cell development have helped establish how cellular signaling controls networks of genetic interactions that bring about morphogenesis and differentiation. This review summarizes studies of pigment cell development and concludes that pigment cells are an excellent experimental model. Pigment cells provide several opportunities to further test and refine our understanding of the molecular basis of cellular development.
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Affiliation(s)
- Robert D Burke
- Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.
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8
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Yaguchi S, Yaguchi J. Temnopleurus reevesii as a new sea urchin model in genetics. Dev Growth Differ 2021; 64:59-66. [PMID: 34923630 DOI: 10.1111/dgd.12768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 11/29/2022]
Abstract
Echinoderms, including sea urchins and starfish, have played important roles in cell, developmental and evolutionary biology research for more than a century. However, since most of them take a long time to mature sexually and their breeding seasons are limited, it has been difficult to obtain subsequent generations in the laboratory, resulting in them not being recognized as model organisms in recent genetics research. To overcome this issue, we maintained and obtained gametes from several nonmodel sea urchins in Japan and finally identified Temnopleurus reevesii as a suitable model for sea urchin genetics. Genomic and transcriptomic information was obtained for this model, and the DNA database TrBase was made publicly available. In this review, we describe how we found this species useful for biological research and show an example of CRISPR/Cas9 based knockout sea urchin.
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Affiliation(s)
- Shunsuke Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan.,PRESTO, JST, 4-1-8 Honcho, Kawaguchi, 332-0012, Japan
| | - Junko Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka, 415-0025, Japan
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9
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Piovani L, Czarkwiani A, Ferrario C, Sugni M, Oliveri P. Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration. BMC Biol 2021; 19:9. [PMID: 33461552 PMCID: PMC7814545 DOI: 10.1186/s12915-020-00937-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 12/02/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Regeneration is the ability to re-grow body parts or tissues after trauma, and it is widespread across metazoans. Cells involved in regeneration can arise from a pool of undifferentiated proliferative cells or be recruited from pre-existing differentiated tissues. Both mechanisms have been described in different phyla; however, the cellular and molecular mechanisms employed by different animals to restore lost tissues as well as the source of cells involved in regeneration remain largely unknown. Echinoderms are a clade of deuterostome invertebrates that show striking larval and adult regenerative abilities in all extant classes. Here, we use the brittle star Amphiura filiformis to investigate the origin and differentiation of cells involved in skeletal regeneration using a combination of microscopy techniques and molecular markers. RESULTS Our ultrastructural analyses at different regenerative stages identify a population of morphologically undifferentiated cells which appear in close contact with the proliferating epithelium of the regenerating aboral coelomic cavity. These cells express skeletogenic marker genes, such as the transcription factor alx1 and the differentiation genes c-lectin and msp130L, and display a gradient of morphological differentiation from the aboral coelomic cavity towards the epidermis. Cells closer to the epidermis, which are in contact with developing spicules, have the morphology of mature skeletal cells (sclerocytes), and express several skeletogenic transcription factors and differentiation genes. Moreover, as regeneration progresses, sclerocytes show a different combinatorial expression of genes in various skeletal elements. CONCLUSIONS We hypothesize that sclerocyte precursors originate from the epithelium of the proliferating aboral coelomic cavity. As these cells migrate towards the epidermis, they differentiate and start secreting spicules. Moreover, our study shows that molecular and cellular processes involved in skeletal regeneration resemble those used during skeletal development, hinting at a possible conservation of developmental programmes during adult regeneration. Finally, we highlight that many genes involved in echinoderm skeletogenesis also play a role in vertebrate skeleton formation, suggesting a possible common origin of the deuterostome endoskeleton pathway.
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Affiliation(s)
- Laura Piovani
- Department of Environmental Science and Policy, University of Milan, Via Celoria, 2, 20133, Milan, Italy
- Department of Genetics, Evolution and Environment, University College London, London, UK
- Center for Life Origins and Evolution, University College London, London, UK
| | - Anna Czarkwiani
- Department of Genetics, Evolution and Environment, University College London, London, UK
- Present Address: DFG-Center for Regenerative Therapies Technische Universität Dresden (CRTD), Dresden, Germany
| | - Cinzia Ferrario
- Department of Environmental Science and Policy, University of Milan, Via Celoria, 2, 20133, Milan, Italy
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria, 16, 20133, Milan, Italy
| | - Michela Sugni
- Department of Environmental Science and Policy, University of Milan, Via Celoria, 2, 20133, Milan, Italy.
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria, 16, 20133, Milan, Italy.
- GAIA 2050 Center, Department of Environmental Science and Policy, University of Milan, Via Celoria, 2, 20133, Milan, Italy.
| | - Paola Oliveri
- Department of Genetics, Evolution and Environment, University College London, London, UK.
- Center for Life Origins and Evolution, University College London, London, UK.
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Plygawko AT, Kan S, Campbell K. Epithelial-mesenchymal plasticity: emerging parallels between tissue morphogenesis and cancer metastasis. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200087. [PMID: 32829692 PMCID: PMC7482222 DOI: 10.1098/rstb.2020.0087] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Many cells possess epithelial–mesenchymal plasticity (EMP), which allows them to shift reversibly between adherent, static and more detached, migratory states. These changes in cell behaviour are driven by the programmes of epithelial–mesenchymal transition (EMT) and mesenchymal–epithelial transition (MET), both of which play vital roles during normal development and tissue homeostasis. However, the aberrant activation of these processes can also drive distinct stages of cancer progression, including tumour invasiveness, cell dissemination and metastatic colonization and outgrowth. This review examines emerging common themes underlying EMP during tissue morphogenesis and malignant progression, such as the context dependence of EMT transcription factors, a central role for partial EMTs and the nonlinear relationship between EMT and MET. This article is part of a discussion meeting issue ‘Contemporary morphogenesis'.
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Affiliation(s)
- Andrew T Plygawko
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Shohei Kan
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Kyra Campbell
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
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11
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Wee K, Hediyeh-Zadeh S, Duszyc K, Verma S, N Nanavati B, Khare S, Varma A, Daly RJ, Yap AS, Davis MJ, Budnar S. Snail induces epithelial cell extrusion by regulating RhoA contractile signalling and cell-matrix adhesion. J Cell Sci 2020; 133:jcs235622. [PMID: 32467325 DOI: 10.1242/jcs.235622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 05/14/2020] [Indexed: 01/06/2023] Open
Abstract
Cell extrusion is a morphogenetic process that is implicated in epithelial homeostasis and elicited by stimuli ranging from apoptosis to oncogenic transformation. To explore whether the morphogenetic transcription factor Snail (SNAI1) induces extrusion, we inducibly expressed a stabilized Snail6SA transgene in confluent MCF-7 monolayers. When expressed in small clusters (less than three cells) within otherwise wild-type confluent monolayers, Snail6SA expression induced apical cell extrusion. In contrast, larger clusters or homogenous cultures of Snail6SA cells did not show enhanced apical extrusion, but eventually displayed sporadic basal delamination. Transcriptomic profiling revealed that Snail6SA did not substantively alter the balance of epithelial and mesenchymal genes. However, we identified a transcriptional network that led to upregulated RhoA signalling and cortical contractility in cells expressing Snail6SA Enhanced contractility was necessary, but not sufficient, to drive extrusion, suggesting that Snail collaborates with other factors. Indeed, we found that the transcriptional downregulation of cell-matrix adhesion cooperates with contractility to mediate basal delamination. This provides a pathway for Snail to influence epithelial morphogenesis independently of classic epithelial-to-mesenchymal transition.
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Affiliation(s)
- Kenneth Wee
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Soroor Hediyeh-Zadeh
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Kinga Duszyc
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Suzie Verma
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Bageshri N Nanavati
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | | | - Amrita Varma
- Viravecs Laboratories CCAMP, GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India
| | - Roger J Daly
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University
| | - Alpha S Yap
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Melissa J Davis
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Srikanth Budnar
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
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12
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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: 2.4] [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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13
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Martin AC. The Physical Mechanisms of Drosophila Gastrulation: Mesoderm and Endoderm Invagination. Genetics 2020; 214:543-560. [PMID: 32132154 PMCID: PMC7054018 DOI: 10.1534/genetics.119.301292] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/21/2019] [Indexed: 12/14/2022] Open
Abstract
A critical juncture in early development is the partitioning of cells that will adopt different fates into three germ layers: the ectoderm, the mesoderm, and the endoderm. This step is achieved through the internalization of specified cells from the outermost surface layer, through a process called gastrulation. In Drosophila, gastrulation is achieved through cell shape changes (i.e., apical constriction) that change tissue curvature and lead to the folding of a surface epithelium. Folding of embryonic tissue results in mesoderm and endoderm invagination, not as individual cells, but as collective tissue units. The tractability of Drosophila as a model system is best exemplified by how much we know about Drosophila gastrulation, from the signals that pattern the embryo to the molecular components that generate force, and how these components are organized to promote cell and tissue shape changes. For mesoderm invagination, graded signaling by the morphogen, Spätzle, sets up a gradient in transcriptional activity that leads to the expression of a secreted ligand (Folded gastrulation) and a transmembrane protein (T48). Together with the GPCR Mist, which is expressed in the mesoderm, and the GPCR Smog, which is expressed uniformly, these signals activate heterotrimeric G-protein and small Rho-family G-protein signaling to promote apical contractility and changes in cell and tissue shape. A notable feature of this signaling pathway is its intricate organization in both space and time. At the cellular level, signaling components and the cytoskeleton exhibit striking polarity, not only along the apical-basal cell axis, but also within the apical domain. Furthermore, gene expression controls a highly choreographed chain of events, the dynamics of which are critical for primordium invagination; it does not simply throw the cytoskeletal "on" switch. Finally, studies of Drosophila gastrulation have provided insight into how global tissue mechanics and movements are intertwined as multiple tissues simultaneously change shape. Overall, these studies have contributed to the view that cells respond to forces that propagate over great distances, demonstrating that cellular decisions, and, ultimately, tissue shape changes, proceed by integrating cues across an entire embryo.
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Affiliation(s)
- Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
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14
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The cellular and molecular mechanisms that establish the mechanics of Drosophila gastrulation. Curr Top Dev Biol 2020; 136:141-165. [DOI: 10.1016/bs.ctdb.2019.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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15
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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: 1.5] [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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16
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Abstract
Gastrulation is arguably the most important evolutionary innovation in the animal kingdom. This process provides the basic embryonic architecture, an inner layer separated from an outer layer, from which all animal forms arise. An extraordinarily simple and elegant process of gastrulation is observed in the sea urchin embryo. The cells participating in sea urchin gastrulation are specified early during cleavage. One outcome of that specification is the expression of transcription factors that control each of the many subsequent morphogenetic changes. The first of these movements is an epithelial-mesenchymal transition (EMT) of skeletogenic mesenchyme cells, then EMT of pigment cell progenitors. Shortly thereafter, invagination of the archenteron occurs. At the end of archenteron extension, a second wave of EMT occurs to release immune cells into the blastocoel and primordial germ cells that will home to the coelomic pouches. The archenteron then remodels to establish the three parts of the gut, and at the anterior end, the gut fuses with the stomodaeum to form the through-gut. As part of the anterior remodeling, mesodermal coelomic pouches bud off the lateral sides of the archenteron tip. Multiple cell biological processes conduct each of these movements and in some cases the upstream transcription factors controlling this process have been identified. Remarkably, each event seamlessly occurs at the right time to orchestrate formation of the primitive body plan. This review covers progress toward understanding many of the molecular mechanisms underlying this sequence of morphogenetic events.
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17
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Evolution of Snail-mediated regulation of neural crest and placodes from an ancient role in bilaterian neurogenesis. Dev Biol 2019; 453:180-190. [PMID: 31211947 DOI: 10.1016/j.ydbio.2019.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 12/26/2022]
Abstract
A major challenge in vertebrate evolution is to identify the gene regulatory mechanisms that facilitated the origin of neural crest cells and placodes from ancestral precursors in invertebrates. Here, we show in lamprey, a primitively jawless vertebrate, that the transcription factor Snail is expressed simultaneously throughout the neural plate, neural plate border, and pre-placodal ectoderm in the early embryo and is then upregulated in the CNS throughout neurogenesis. Using CRISPR/Cas9-mediated genome editing, we demonstrate that Snail plays functional roles in all of these embryonic domains or their derivatives. We first show that Snail patterns the neural plate border by repressing lateral expansion of Pax3/7 and activating nMyc and ZicA. We also present evidence that Snail is essential for DlxB-mediated establishment of the pre-placodal ectoderm but is not required for SoxB1a expression during formation of the neural plate proper. At later stages, Snail regulates formation of neural crest-derived and placode-derived PNS neurons and controls CNS neural differentiation in part by promoting cell survival. Taken together with established functions of invertebrate Snail genes, we identify a pan-bilaterian mechanism that extends to jawless vertebrates for regulating neurogenesis that is dependent on Snail transcription factors. We propose that ancestral vertebrates deployed an evolutionarily conserved Snail expression domain in the CNS and PNS for neurogenesis and then acquired derived functions in neural crest and placode development by recruitment of regulatory genes downstream of neuroectodermal Snail activity. Our results suggest that Snail regulatory mechanisms in vertebrate novelties such as the neural crest and placodes may have emerged from neurogenic roles that originated early in bilaterian evolution.
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18
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Molina MD, Gache C, Lepage T. Expression of exogenous mRNAs to study gene function in echinoderm embryos. Methods Cell Biol 2019; 151:239-282. [PMID: 30948011 DOI: 10.1016/bs.mcb.2018.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
With the completion of the genome sequencing projects, a new challenge for developmental biologists is to assign a function to the thousands of genes identified. Expression of exogenous mRNAs is a powerful, versatile and rapid technique that can be used to study gene function during development of the sea urchin. This chapter describes how this technique can be used to analyze gene function in echinoderm embryos, how it can be combined with cell transplantation to perform mosaic analysis and how it can be applied to identify downstream targets genes of transcription factors and signaling pathways. We describe specific examples of the use of overexpression of mRNA to analyze gene function, mention the benefits and current limitations of the technique and emphasize the importance of using different controls to assess the specificity of the effects observed. Finally, this chapter details the different steps, vectors and protocols for in vitro production of mRNA and phenotypic analysis.
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Affiliation(s)
| | - Christian Gache
- Université Pierre et Marie Curie, Observatoire Océanologique de Villefranche sur Mer, UMR7009 CNRS, Paris, France
| | - Thierry Lepage
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France.
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19
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Osborne CC, Perry KJ, Shankland M, Henry JQ. Ectomesoderm and epithelial-mesenchymal transition-related genes in spiralian development. Dev Dyn 2018; 247:1097-1120. [PMID: 30133032 DOI: 10.1002/dvdy.24667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Spiralians (e.g., annelids, molluscs, and flatworms) possess two sources of mesoderm. One is from endodermal precursors (endomesoderm), which is considered to be the ancestral source in metazoans. The second is from ectoderm (ectomesoderm) and may represent a novel cell type in the Spiralia. In the mollusc Crepidula fornicata, ectomesoderm is derived from micromere daughters within the A and B cell quadrants. Their progeny lie along the anterolateral edges of the blastopore. There they undergo epithelial-mesenchymal transition (EMT), become rounded and undergo delamination/ingression. Subsequently, they assume the mesenchymal phenotype, and migrate beneath the surface ectoderm to differentiate various cell types, including muscles and pigment cells. RESULTS We examined expression of several genes whose homologs are known to regulate Type 1 EMT in other metazoans. Most of these genes were expressed within spiralian ectomesoderm during EMT. CONCLUSIONS We propose that spiralian ectomesoderm, which exhibits analogous cellular behaviors to other populations of mesenchymal cells, may be controlled by the same genes that drive EMT in other metazoans. Perhaps these genes comprise a conserved metazoan EMT gene regulatory network (GRN). This study represents the first step in elucidating the GRN controlling the development of a novel spiralian cell type (ectomesoderm). Developmental Dynamics 247:1097-1120, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- C Cornelia Osborne
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
| | - Kimberly J Perry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
| | - Marty Shankland
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
| | - Jonathan Q Henry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
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20
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Shashikant T, Khor JM, Ettensohn CA. From genome to anatomy: The architecture and evolution of the skeletogenic gene regulatory network of sea urchins and other echinoderms. Genesis 2018; 56:e23253. [PMID: 30264451 PMCID: PMC6294693 DOI: 10.1002/dvg.23253] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/14/2018] [Accepted: 09/23/2018] [Indexed: 01/19/2023]
Abstract
The skeletogenic gene regulatory network (GRN) of sea urchins and other echinoderms is one of the most intensively studied transcriptional networks in any developing organism. As such, it serves as a preeminent model of GRN architecture and evolution. This review summarizes our current understanding of this developmental network. We describe in detail the most comprehensive model of the skeletogenic GRN, one developed for the euechinoid sea urchin Strongylocentrotus purpuratus, including its initial deployment by maternal inputs, its elaboration and stabilization through regulatory gene interactions, and its control of downstream effector genes that directly drive skeletal morphogenesis. We highlight recent comparative studies that have leveraged the euechinoid GRN model to examine the evolution of skeletogenic programs in diverse echinoderms, studies that have revealed both conserved and divergent features of skeletogenesis within the phylum. Last, we summarize the major insights that have emerged from analysis of the structure and evolution of the echinoderm skeletogenic GRN and identify key, unresolved questions as a guide for future work.
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Affiliation(s)
- Tanvi Shashikant
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
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21
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Fan TP, Ting HC, Yu JK, Su YH. Reiterative use of FGF signaling in mesoderm development during embryogenesis and metamorphosis in the hemichordate Ptychodera flava. BMC Evol Biol 2018; 18:120. [PMID: 30075704 PMCID: PMC6091094 DOI: 10.1186/s12862-018-1235-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 07/26/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Mesoderm is generally considered to be a germ layer that is unique to Bilateria, and it develops into diverse tissues, including muscle, and in the case of vertebrates, the skeleton and notochord. Studies on various deuterostome animals have demonstrated that fibroblast growth factor (FGF) signaling is required for the formation of many mesodermal structures, such as vertebrate somites, from which muscles are differentiated, and muscles in sea urchin embryos, suggesting an ancient role of FGF signaling in muscle development. However, the formation of trunk muscles in invertebrate chordates is FGF-independent, leading to ambiguity about this ancient role in deuterostomes. To further understand the role of FGF signaling during deuterostome evolution, we investigated the development of mesodermal structures during embryogenesis and metamorphosis in Ptychodera flava, an indirect-developing hemichordate that has larval morphology similar to echinoderms and adult body features that are similar to chordates. RESULTS Here we show that genes encoding FGF ligands, FGF receptors and transcription factors that are known to be involved in mesoderm formation and myogenesis are expressed dynamically during embryogenesis and metamorphosis. FGF signaling at the early gastrula stage is required for the specification of the mesodermal cell fate in P. flava. The mesoderm cells are then differentiated stepwise into the hydroporic canal, the pharyngeal muscle and the muscle string; formation of the last two muscular structures are controlled by FGF signaling. Moreover, augmentation of FGF signaling during metamorphosis accelerated the process, facilitating the transformation from cilia-driven swimming larvae into muscle-driven worm-like juveniles. CONCLUSIONS Our data show that FGF signaling is required for mesoderm induction and myogenesis in the P. flava embryo, and it is reiteratively used for the morphological transition during metamorphosis. The dependence of muscle development on FGF signaling in both planktonic larvae and sand-burrowing worms supports its ancestral role in deuterostomes.
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Affiliation(s)
- Tzu-Pei Fan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan.,Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Hsiu-Chi Ting
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan
| | - Yi-Hsien Su
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan. .,Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan. .,Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan.
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22
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Aiello NM, Maddipati R, Norgard RJ, Balli D, Li J, Yuan S, Yamazoe T, Black T, Sahmoud A, Furth EE, Bar-Sagi D, Stanger BZ. EMT Subtype Influences Epithelial Plasticity and Mode of Cell Migration. Dev Cell 2018; 45:681-695.e4. [PMID: 29920274 PMCID: PMC6014628 DOI: 10.1016/j.devcel.2018.05.027] [Citation(s) in RCA: 479] [Impact Index Per Article: 68.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/20/2017] [Accepted: 05/21/2018] [Indexed: 12/13/2022]
Abstract
Epithelial-mesenchymal transition (EMT) is strongly implicated in tumor cell invasion and metastasis. EMT is thought to be regulated primarily at the transcriptional level through the repressive activity of EMT transcription factors. However, these classical mechanisms have been parsed out almost exclusively in vitro, leaving questions about the programs driving EMT in physiological contexts. Here, using a lineage-labeled mouse model of pancreatic ductal adenocarcinoma to study EMT in vivo, we found that most tumors lose their epithelial phenotype through an alternative program involving protein internalization rather than transcriptional repression, resulting in a "partial EMT" phenotype. Carcinoma cells utilizing this program migrate as clusters, contrasting with the single-cell migration pattern associated with traditionally defined EMT mechanisms. Moreover, many breast and colorectal cancer cell lines utilize this alternative program to undergo EMT. Collectively, these results suggest that carcinoma cells have different ways of losing their epithelial program, resulting in distinct modes of invasion and dissemination.
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Affiliation(s)
- Nicole M Aiello
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Ravikanth Maddipati
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Robert J Norgard
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - David Balli
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Jinyang Li
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Salina Yuan
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Taiji Yamazoe
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Taylor Black
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Amine Sahmoud
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA
| | - Emma E Furth
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dafna Bar-Sagi
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ben Z Stanger
- Department of Medicine, Gastroenterology Division, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, 421 Curie Blvd, 512 BRB II/III, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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23
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Paleogenomics of echinoids reveals an ancient origin for the double-negative specification of micromeres in sea urchins. Proc Natl Acad Sci U S A 2018; 114:5870-5877. [PMID: 28584090 DOI: 10.1073/pnas.1610603114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Establishing a timeline for the evolution of novelties is a common, unifying goal at the intersection of evolutionary and developmental biology. Analyses of gene regulatory networks (GRNs) provide the ability to understand the underlying genetic and developmental mechanisms responsible for the origin of morphological structures both in the development of an individual and across entire evolutionary lineages. Accurately dating GRN novelties, thereby establishing a timeline for GRN evolution, is necessary to answer questions about the rate at which GRNs and their subcircuits evolve, and to tie their evolution to paleoenvironmental and paleoecological changes. Paleogenomics unites the fossil record and all aspects of deep time, with modern genomics and developmental biology to understand the evolution of genomes in evolutionary time. Recent work on the regulatory genomic basis of development in cidaroid echinoids, sand dollars, heart urchins, and other nonmodel echinoderms provides an ideal dataset with which to explore GRN evolution in a comparative framework. Using divergence time estimation and ancestral state reconstructions, we have determined the age of the double-negative gate (DNG), the subcircuit which specifies micromeres and skeletogenic cells in Strongylocentrotus purpuratus We have determined that the DNG has likely been used for euechinoid echinoid micromere specification since at least the Late Triassic. The innovation of the DNG thus predates the burst of post-Paleozoic echinoid morphological diversification that began in the Early Jurassic. Paleogenomics has wide applicability for the integration of deep time and molecular developmental data, and has wide utility in rigorously establishing timelines for GRN evolution.
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24
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Pasiliao CC, Hopyan S. Cell ingression: Relevance to limb development and for adaptive evolution. Genesis 2017; 56. [PMID: 29280270 DOI: 10.1002/dvg.23086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 11/16/2017] [Accepted: 12/05/2017] [Indexed: 12/11/2022]
Abstract
Cell ingression is an out-of-plane type of cell intercalation that is essential for the formation of multiple embryonic structures including the limbs. In particular, cell ingression underlies epithelial-to-mesenchymal transition of lateral plate cells to initiate limb bud growth, delamination of neural crest cells to generate peripheral nerve sheaths, and emigration of myoblasts from somites to assemble muscles. Individual cells that ingress undergo apical constriction to generate bottle shaped cells, diminish adhesion to their epithelial cell neighbors, and generate protrusive blebs that likely facilitate their ingression into a subepithelial tissue layer. How signaling pathways regulate the progression of delamination is important for understanding numerous developmental events. In this review, we focus on cellular and molecular mechanisms that drive cell ingression and draw comparisons between different morphogenetic contexts in various model organisms. We speculate that cell behaviors that facilitated tissue invagination among diploblasts subsequently drove individual cell ingression and epithelial-to-mesenchymal transition. Future insights that link signalling pathways to biophysical mechanisms will likely advance our comprehension of this phenomenon.
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Affiliation(s)
- Clarissa C Pasiliao
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, M5S 1A8, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, M5S 1A8, Canada.,Division of Orthopaedic Surgery, Hospital for Sick Children and University of, Toronto, M5G 1X8, Canada
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25
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Romancino DP, Anello L, Lavanco A, Buffa V, Di Bernardo M, Bongiovanni A. A sea urchin in vivo model to evaluate Epithelial-Mesenchymal Transition. Dev Growth Differ 2017; 59:141-151. [PMID: 28436008 DOI: 10.1111/dgd.12353] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 03/30/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022]
Abstract
Epithelial-mesenchymal transition (EMT) is an evolutionarily conserved cellular program, which is a prerequisite for the metastatic cascade in carcinoma progression. Here, we evaluate the EMT process using the sea urchin Paracentrotus lividus embryo. In sea urchin embryos, the earliest EMT event is related to the acquisition of a mesenchymal phenotype by the spiculogenetic primary mesenchyme cells (PMCs) and their migration into the blastocoel. We investigated the effect of inhibiting the epidermal growth factor (EGF) signaling pathway on this process, and we observed that mesenchyme cell differentiation was blocked. In order to extend and validate our studies, we investigated the migratory capability and the level of potential epidermal growth factor receptor (EGFr) targets in a breast cancer cell line after EGF modulation. Altogether, our data highlight the sensitivity of the sea urchin embryo to anti-EMT drugs and pinpoint the sea urchin embryo as a valuable in vivo model system for studying EMT and the screening of anti-EMT candidates.
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Affiliation(s)
- Daniele P Romancino
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
| | - Letizia Anello
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
| | - Antonella Lavanco
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
| | - Valentina Buffa
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
| | - Maria Di Bernardo
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
| | - Antonella Bongiovanni
- Institute of Biomedicine and Molecular Immunology (IBIM), National Research Council (CNR), via Ugo La Malfa, 153 - 90146, Palermo, Italy
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26
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Simões S, Oh Y, Wang MFZ, Fernandez-Gonzalez R, Tepass U. Myosin II promotes the anisotropic loss of the apical domain during Drosophila neuroblast ingression. J Cell Biol 2017; 216:1387-1404. [PMID: 28363972 PMCID: PMC5412560 DOI: 10.1083/jcb.201608038] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/15/2016] [Accepted: 02/14/2017] [Indexed: 01/06/2023] Open
Abstract
Drosophila neural stem cells, or neuroblasts, ingress from the neuroepithelium in an EMT-like process, during which the apical cell domain is lost. Apical constriction of neuroblasts and the serial loss of cell–cell contacts require periodic pulses of actomyosin that cause progressively stronger ratcheted contractions of the neuroblast apical cortex. Epithelial–mesenchymal transitions play key roles in development and cancer and entail the loss of epithelial polarity and cell adhesion. In this study, we use quantitative live imaging of ingressing neuroblasts (NBs) in Drosophila melanogaster embryos to assess apical domain loss and junctional disassembly. Ingression is independent of the Snail family of transcriptional repressors and down-regulation of Drosophila E-cadherin (DEcad) transcription. Instead, the posttranscriptionally regulated decrease in DEcad coincides with the reduction of cell contact length and depends on tension anisotropy between NBs and their neighbors. A major driver of apical constriction and junctional disassembly are periodic pulses of junctional and medial myosin II that result in progressively stronger cortical contractions during ingression. Effective contractions require the molecular coupling between myosin and junctions and apical relaxation of neighboring cells. Moreover, planar polarization of myosin leads to the loss of anterior–posterior junctions before the loss of dorsal–ventral junctions. We conclude that planar-polarized dynamic actomyosin networks drive apical constriction and the anisotropic loss of cell contacts during NB ingression.
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Affiliation(s)
- Sérgio Simões
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Youjin Oh
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Michael F Z Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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27
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Cavalieri V, Geraci F, Spinelli G. Diversification of spatiotemporal expression and copy number variation of the echinoid hbox12/pmar1/micro1 multigene family. PLoS One 2017; 12:e0174404. [PMID: 28350855 PMCID: PMC5370098 DOI: 10.1371/journal.pone.0174404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 03/08/2017] [Indexed: 11/26/2022] Open
Abstract
Changes occurring during evolution in the cis-regulatory landscapes of individual members of multigene families might impart diversification in their spatiotemporal expression and function. The archetypal member of the echinoid hbox12/pmar1/micro1 family is hbox12-a, a homeobox-containing gene expressed exclusively by dorsal blastomeres, where it governs the dorsal/ventral gene regulatory network during embryogenesis of the sea urchin Paracentrotus lividus. Here we describe the inventory of the hbox12/pmar1/micro1 genes in P. lividus, highlighting that gene copy number variation occurs across individual sea urchins of the same species. We show that the various hbox12/pmar1/micro1 genes group into three subfamilies according to their spatiotemporal expression, which ranges from broad transcription throughout development to transient expression in either the animal hemisphere or micromeres of the early embryo. Interestingly, the promoter regions of those genes showing comparable expression patterns are highly similar, while differing from those of the other subfamilies. Strikingly, phylogenetic analysis suggests that the hbox12/pmar1/micro1 genes are species-specific, exhibiting extensive divergence in their noncoding, but not in their coding, sequences across three distinct sea urchin species. In spite of this, two micromere-specific genes of P. lividus possess a TCF/LEF-binding motif in a similar position, and their transcription relies on Wnt/β-catenin signaling, similar to the pmar1 and micro1 genes, which in other sea urchin species are involved in micromere specification. Altogether, our findings suggest that the hbox12/pmar1/micro1 gene family evolved rather rapidly, generating paralogs whose cis-regulatory sequences diverged following multiple rounds of duplication from a common ancestor.
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Affiliation(s)
- Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Edificio 16, Palermo, Italy
- Advanced Technologies Network Center (ATeN), University of Palermo, Viale delle Scienze Edificio 18, Palermo, Italy
- * E-mail: (VC); (GS)
| | - Fabiana Geraci
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Edificio 16, Palermo, Italy
| | - Giovanni Spinelli
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Edificio 16, Palermo, Italy
- * E-mail: (VC); (GS)
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Stepicheva NA, Dumas M, Kobi P, Donaldson JG, Song JL. The small GTPase Arf6 regulates sea urchin morphogenesis. Differentiation 2017; 95:31-43. [PMID: 28188999 DOI: 10.1016/j.diff.2017.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 12/08/2016] [Accepted: 01/26/2017] [Indexed: 12/31/2022]
Abstract
The small GTPase Arf6 is a conserved protein that is expressed in all metazoans. Arf6 remodels cytoskeletal actin and mediates membrane protein trafficking between the plasma membrane in its active form and endosomal compartments in its inactive form. While a rich knowledge exists for the cellular functions of Arf6, relatively little is known about its physiological role in development. This study examines the function of Arf6 in mediating cellular morphogenesis in early development. We dissect the function of Arf6 with a loss-of-function morpholino and constitutively active Arf6-Q67L construct. We focus on the two cell types that undergo active directed migration: the primary mesenchyme cells (PMCs) that give rise to the sea urchin skeleton and endodermal cells that form the gut. Our results indicate that Arf6 plays an important role in skeleton formation and PMC migration, in part due to its ability to remodel actin. We also found that embryos injected with Arf6 morpholino have gastrulation defects and embryos injected with constitutively active Arf6 have endodermal cells detached from the gut epithelium with decreased junctional cadherin staining, indicating that Arf6 may mediate the recycling of cadherin. Thus, Arf6 impacts cells that undergo coordinated movement to form embryonic structures in the developing embryo.
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Affiliation(s)
- Nadezda A Stepicheva
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States
| | - Megan Dumas
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States
| | - Priscilla Kobi
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States
| | - Julie G Donaldson
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jia L Song
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States.
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29
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Acloque H, Ocaña OH, Abad D, Stern CD, Nieto MA. Snail2 and Zeb2 repress P-cadherin to define embryonic territories in the chick embryo. Development 2017; 144:649-656. [PMID: 28087626 DOI: 10.1242/dev.142562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 12/23/2016] [Indexed: 12/12/2022]
Abstract
Snail and Zeb transcription factors induce epithelial-to-mesenchymal transition (EMT) in embryonic and adult tissues by direct repression of E-cadherin transcription. The repression of E-cadherin transcription by the EMT inducers Snail1 and Zeb2 plays a fundamental role in defining embryonic territories in the mouse, as E-cadherin needs to be downregulated in the primitive streak and in the epiblast, concomitant with the formation of mesendodermal precursors and the neural plate, respectively. Here, we show that in the chick embryo, E-cadherin is weakly expressed in the epiblast at pre-primitive streak stages where it is substituted for by P-cadherin We also show that Snail2 and Zeb2 repress P-cadherin transcription in the primitive streak and the neural plate, respectively. This indicates that E- and P-cadherin expression patterns evolved differently between chick and mouse. As such, the Snail1/E-cadherin axis described in the early mouse embryo corresponds to Snail2/P-cadherin in the chick, but both Snail factors and Zeb2 fulfil a similar role in chick and mouse in directly repressing ectodermal cadherin genes to contribute to the delamination of mesendodermal precursors at gastrulation and the proper specification of the neural ectoderm during neural induction.
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Affiliation(s)
- Hervé Acloque
- Instituto de Neurociencias de Alicante, CSIC-UMH, Avenida Ramón y Cajal s/n, San Juan de Alicante 03550, Spain .,GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet Tolosan 31326, France
| | - Oscar H Ocaña
- Instituto de Neurociencias de Alicante, CSIC-UMH, Avenida Ramón y Cajal s/n, San Juan de Alicante 03550, Spain
| | - Diana Abad
- Instituto de Neurociencias de Alicante, CSIC-UMH, Avenida Ramón y Cajal s/n, San Juan de Alicante 03550, Spain
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - M Angela Nieto
- Instituto de Neurociencias de Alicante, CSIC-UMH, Avenida Ramón y Cajal s/n, San Juan de Alicante 03550, Spain
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30
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Yu Q, Zhou BP, Wu Y. The regulation of snail: on the ubiquitin edge. CANCER CELL & MICROENVIRONMENT 2017; 4:e1567. [PMID: 29147673 PMCID: PMC5685547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Metastasis accounts for a majority of cancer death. One key feature during metastasis is epithelial-mesenchymal transition (EMT), which is regulated by transcription factors such as Snail and Twist. In non-malignant cells, Snail has a short half-life and is degraded via ubiquitination, but its stability is increased in cancer cell. However, the mechanism by which Snail escapes ubiquitination and degradation remains unknown. Recently, we found that Dub3 is a deubiquinase of Snail. Most importantly, we determined that Dub3 responded to extracellular signals such as IL-6, and that the resultant signaling prevented Snail degradation, and promoted cancer growth, invasion, and migration. In this highlight, we present a concise picture of how the transcription factor Snail is regulated by ubiquitination in cancer cells, the role of Dub3 in this process, and its potential use as a treatment target.
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Affiliation(s)
- Qian Yu
- Pharmacology and Nutritional Sciences, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA,Markey Cancer Center, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA
| | - Binhua P. Zhou
- Molecular and Cellular Biochemistry, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA,Markey Cancer Center, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA
| | - Yadi Wu
- Pharmacology and Nutritional Sciences, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA,Markey Cancer Center, the University of Kentucky, College of Medicine, Lexington, KY 40506, USA
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31
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Abstract
Tissue-specific transcription regulators emerged as key developmental control genes, which operate in the context of complex gene regulatory networks (GRNs) to coordinate progressive cell fate specification and tissue morphogenesis. We discuss how GRNs control the individual cell behaviors underlying complex morphogenetic events. Cell behaviors classically range from mesenchymal cell motility to cell shape changes in epithelial sheets. These behaviors emerge from the tissue-specific, multiscale integration of the local activities of universal and pleiotropic effectors, which underlie modular subcellular processes including cytoskeletal dynamics, cell-cell and cell-matrix adhesion, signaling, polarity, and vesicle trafficking. Extrinsic cues and intrinsic cell competence determine the subcellular spatiotemporal patterns of effector activities. GRNs influence most subcellular activities by controlling only a fraction of the effector-coding genes, which we argue is enriched in effectors involved in reading and processing the extrinsic cues to contextualize intrinsic subcellular processes and canalize developmental cell behaviors. The properties of the transcription-cell behavior interface have profound implications for evolution and disease.
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Affiliation(s)
- Yelena Bernadskaya
- Center for Developmental Genetics, Department of Biology, New York University, New York, NY 10003
| | - Lionel Christiaen
- Center for Developmental Genetics, Department of Biology, New York University, New York, NY 10003
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32
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Perry KJ, Lyons DC, Truchado-Garcia M, Fischer AHL, Helfrich LW, Johansson KB, Diamond JC, Grande C, Henry JQ. Deployment of regulatory genes during gastrulation and germ layer specification in a model spiralian mollusc Crepidula. Dev Dyn 2016. [PMID: 26197970 DOI: 10.1002/dvdy.24308] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND During gastrulation, endoderm and mesoderm are specified from a bipotential precursor (endomesoderm) that is argued to be homologous across bilaterians. Spiralians also generate mesoderm from ectodermal precursors (ectomesoderm), which arises near the blastopore. While a conserved gene regulatory network controls specification of endomesoderm in deuterostomes and ecdysozoans, little is known about genes controlling specification or behavior of either source of spiralian mesoderm or the digestive tract. RESULTS Using the mollusc Crepidula, we examined conserved regulatory factors and compared their expression to fate maps to score expression in the germ layers, blastopore lip, and digestive tract. Many genes were expressed in both ecto- and endomesoderm, but only five were expressed in ectomesoderm exclusively. The latter may contribute to epithelial-to-mesenchymal transition seen in ectomesoderm. CONCLUSIONS We present the first comparison of genes expressed during spiralian gastrulation in the context of high-resolution fate maps. We found variation of genes expressed in the blastopore lip, mouth, and cells that will form the anus. Shared expression of many genes in both mesodermal sources suggests that components of the conserved endomesoderm program were either co-opted for ectomesoderm formation or that ecto- and endomesoderm are derived from a common mesodermal precursor that became subdivided into distinct domains during evolution.
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Affiliation(s)
- Kimberly J Perry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
| | | | - Marta Truchado-Garcia
- Departamento de Biología Molecular and Centro de Biología Molecular, "Severo Ochoa" (CSIC, Universidad Autónoma de Madrid), Madrid, Spain
| | - Antje H L Fischer
- Department of Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany.,Marine Biological Laboratory, Woods Hole, Massachusetts
| | | | - Kimberly B Johansson
- Marine Biological Laboratory, Woods Hole, Massachusetts.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts
| | | | - Cristina Grande
- Departamento de Biología Molecular and Centro de Biología Molecular, "Severo Ochoa" (CSIC, Universidad Autónoma de Madrid), Madrid, Spain
| | - Jonathan Q Henry
- University of Illinois, Department of Cell and Developmental Biology, Urbana, Illinois
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33
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Liu J, Lin PC, Zhou BP. Inflammation fuels tumor progress and metastasis. Curr Pharm Des 2016; 21:3032-40. [PMID: 26004407 DOI: 10.2174/1381612821666150514105741] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/12/2015] [Indexed: 12/14/2022]
Abstract
Inflammation is a beneficial response that can remove pathogens, repair injured tissue and restore homeostasis to damaged tissues and organs. However, increasing evidence indicate that chronic inflammation plays a pivotal role in tumor development, as well as progression, metastasis, and resistance to chemotherapy. We will review the current knowledge regarding the contribution of inflammation to epithelial mesenchymal transition. We will also provide some perspectives on the relationship between ER-stress signals and metabolism, and the role of these processes in the development of inflammation.
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Affiliation(s)
| | | | - Binhua P Zhou
- Department of Molecular and Cellular Biochemistry, 741 South Limestone Street, Lexington, KY 40536.
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34
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Stepicheva NA, Song JL. microRNA-31 modulates skeletal patterning in the sea urchin embryo. Development 2015; 142:3769-80. [PMID: 26400092 DOI: 10.1242/dev.127969] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/03/2015] [Indexed: 01/25/2023]
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that repress the translation and reduce the stability of target mRNAs in animal cells. microRNA-31 (miR-31) is known to play a role in cancer, bone formation and lymphatic development. However, studies to understand the function of miR-31 in embryogenesis have been limited. We examined the regulatory role of miR-31 in early development using the sea urchin as a model. miR-31 is expressed at all stages of development and its knockdown (KD) disrupts the patterning and function of primary mesenchyme cells (PMCs), which form the embryonic skeleton spicules. We identified that miR-31 directly represses Pmar1, Alx1, Snail and VegfR7 within the PMC gene regulatory network using reporter constructs. Further, blocking the miR-31-mediated repression of Alx1 and/or VegfR7 in the developing embryo resulted in defects in PMC patterning and skeletogenesis. The majority of the mislocalized PMCs in miR-31 KD embryos did not express VegfR10, indicating that miR-31 regulates VegfR gene expression within PMCs. In addition, miR-31 indirectly suppresses Vegf3 expression in the ectoderm. These results indicate that miR-31 coordinately suppresses genes within the PMCs and in the ectoderm to impact PMC patterning and skeletogenesis. This study identifies the novel function and molecular mechanism of miR-31-mediated regulation in the developing embryo.
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Affiliation(s)
- Nadezda A Stepicheva
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jia L Song
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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35
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Cheng X, Lyons DC, Socolar JES, McClay DR. Delayed transition to new cell fates during cellular reprogramming. Dev Biol 2014; 391:147-57. [PMID: 24780626 PMCID: PMC4064802 DOI: 10.1016/j.ydbio.2014.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 01/08/2023]
Abstract
In many embryos specification toward one cell fate can be diverted to a different cell fate through a reprogramming process. Understanding how that process works will reveal insights into the developmental regulatory logic that emerged from evolution. In the sea urchin embryo, cells at gastrulation were found to reprogram and replace missing cell types after surgical dissections of the embryo. Non-skeletogenic mesoderm (NSM) cells reprogrammed to replace missing skeletogenic mesoderm cells and animal caps reprogrammed to replace all endomesoderm. In both cases evidence of reprogramming onset was first observed at the early gastrula stage, even if the cells to be replaced were removed earlier in development. Once started however, the reprogramming occurred with compressed gene expression dynamics. The NSM did not require early contact with the skeletogenic cells to reprogram, but the animal cap cells gained the ability to reprogram early in gastrulation only after extended contact with the vegetal halves prior to that time. If the entire vegetal half was removed at early gastrula, the animal caps reprogrammed and replaced the vegetal half endomesoderm. If the animal caps carried morpholinos to either hox11/13b or foxA (endomesoderm specification genes), the isolated animal caps failed to reprogram. Together these data reveal that the emergence of a reprogramming capability occurs at early gastrulation in the sea urchin embryo and requires activation of early specification components of the target tissues.
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Affiliation(s)
- Xianrui Cheng
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA; Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Deirdre C Lyons
- Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Joshua E S Socolar
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA; Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA; Department of Physics, Duke University, Durham, NC 27708, USA.
| | - David R McClay
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA; Duke Center for Systems Biology, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, Durham, NC 27708, USA.
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36
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Lyons DC, Martik ML, Saunders LR, McClay DR. Specification to biomineralization: following a single cell type as it constructs a skeleton. Integr Comp Biol 2014; 54:723-33. [PMID: 25009306 DOI: 10.1093/icb/icu087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The sea urchin larva is shaped by a calcite endoskeleton. That skeleton is built by 64 primary mesenchyme cells (PMCs) in Lytechinus variegatus. The PMCs originate as micromeres due to an unequal fourth cleavage in the embryo. Micromeres are specified in a well-described molecular sequence and enter the blastocoel at a precise time using a classic epithelial-mesenchymal transition. To make the skeleton, the PMCs receive signaling inputs from the overlying ectoderm, which provides positional information as well as control of the growth of initial skeletal tri-radiates. The patterning of the skeleton is the result both of autonomous inputs from PMCs, including production of proteins that are included in the skeletal matrix, and of non-autonomous dynamic information from the ectoderm. Here, we summarize the wealth of information known about how a PMC contributes to the skeletal structure. The larval skeleton is a model for understanding how information encoded in DNA is translated into a three-dimensional crystalline structure.
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Affiliation(s)
- Deirdre C Lyons
- Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Megan L Martik
- Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA
| | - Lindsay R Saunders
- Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA
| | - David R McClay
- Department of Biology, Duke University, 124 Science Drive, Box 90338, Durham, NC 27708, USA
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37
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McEwen AE, Maher MT, Mo R, Gottardi CJ. E-cadherin phosphorylation occurs during its biosynthesis to promote its cell surface stability and adhesion. Mol Biol Cell 2014; 25:2365-74. [PMID: 24966173 PMCID: PMC4142610 DOI: 10.1091/mbc.e14-01-0690] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
E-cadherin is highly phosphorylated within its β-catenin-binding region, and this phosphorylation increases its affinity for β-catenin in vitro. However, the identification of key serines responsible for most cadherin phosphorylation and the adhesive consequences of modification at such serines have remained unknown. In this study, we show that as few as three serines in the β-catenin-binding domain of E-cadherin are responsible for most radioactive phosphate incorporation. These serines are required for binding to β-catenin and the mutual stability of both E-cadherin and β-catenin. Cells expressing a phosphodeficient (3S>A) E-cadherin exhibit minimal cell-cell adhesion due to enhanced endocytosis and degradation through a lysosomal compartment. Conversely, negative charge substitution at these serines (3S>D) antagonizes cadherin endocytosis and restores wild-type levels of adhesion. The cadherin kinase is membrane proximal and modifies the cadherin before it reaches the cell surface. Together these data suggest that E-cadherin phosphorylation is largely constitutive and integral to cadherin-catenin complex formation, surface stability, and function.
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Affiliation(s)
- Abbye E McEwen
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611Driskill Graduate Training Program in Life Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Meghan T Maher
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611Driskill Graduate Training Program in Life Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Rigen Mo
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611Molecular Oncology Group, Kadmon Research Institute, New York, NY 10016
| | - Cara J Gottardi
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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Rafiq K, Shashikant T, McManus CJ, Ettensohn CA. Genome-wide analysis of the skeletogenic gene regulatory network of sea urchins. Development 2014; 141:950-61. [PMID: 24496631 DOI: 10.1242/dev.105585] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A central challenge of developmental and evolutionary biology is to understand the transformation of genetic information into morphology. Elucidating the connections between genes and anatomy will require model morphogenetic processes that are amenable to detailed analysis of cell/tissue behaviors and to systems-level approaches to gene regulation. The formation of the calcified endoskeleton of the sea urchin embryo is a valuable experimental system for developing such an integrated view of the genomic regulatory control of morphogenesis. A transcriptional gene regulatory network (GRN) that underlies the specification of skeletogenic cells (primary mesenchyme cells, or PMCs) has recently been elucidated. In this study, we carried out a genome-wide analysis of mRNAs encoded by effector genes in the network and uncovered transcriptional inputs into many of these genes. We used RNA-seq to identify >400 transcripts differentially expressed by PMCs during gastrulation, when these cells undergo a striking sequence of behaviors that drives skeletal morphogenesis. Our analysis expanded by almost an order of magnitude the number of known (and candidate) downstream effectors that directly mediate skeletal morphogenesis. We carried out genome-wide analysis of (1) functional targets of Ets1 and Alx1, two pivotal, early transcription factors in the PMC GRN, and (2) functional targets of MAPK signaling, a pathway that plays an essential role in PMC specification. These studies identified transcriptional inputs into >200 PMC effector genes. Our work establishes a framework for understanding the genomic regulatory control of a major morphogenetic process and has important implications for reconstructing the evolution of biomineralization in metazoans.
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Affiliation(s)
- Kiran Rafiq
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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39
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Saunders LR, McClay DR. Sub-circuits of a gene regulatory network control a developmental epithelial-mesenchymal transition. Development 2014; 141:1503-13. [PMID: 24598159 DOI: 10.1242/dev.101436] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Epithelial-mesenchymal transition (EMT) is a fundamental cell state change that transforms epithelial to mesenchymal cells during embryonic development, adult tissue repair and cancer metastasis. EMT includes a complex series of intermediate cell state changes including remodeling of the basement membrane, apical constriction, epithelial de-adhesion, directed motility, loss of apical-basal polarity, and acquisition of mesenchymal adhesion and polarity. Transcriptional regulatory state changes must ultimately coordinate the timing and execution of these cell biological processes. A well-characterized gene regulatory network (GRN) in the sea urchin embryo was used to identify the transcription factors that control five distinct cell changes during EMT. Single transcription factors were perturbed and the consequences followed with in vivo time-lapse imaging or immunostaining assays. The data show that five different sub-circuits of the GRN control five distinct cell biological activities, each part of the complex EMT process. Thirteen transcription factors (TFs) expressed specifically in pre-EMT cells were required for EMT. Three TFs highest in the GRN specified and activated EMT (alx1, ets1, tbr) and the 10 TFs downstream of those (tel, erg, hex, tgif, snail, twist, foxn2/3, dri, foxb, foxo) were also required for EMT. No single TF functioned in all five sub-circuits, indicating that there is no EMT master regulator. Instead, the resulting sub-circuit topologies suggest EMT requires multiple simultaneous regulatory mechanisms: forward cascades, parallel inputs and positive-feedback lock downs. The interconnected and overlapping nature of the sub-circuits provides one explanation for the seamless orchestration by the embryo of cell state changes leading to successful EMT.
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40
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Schäfer G, Narasimha M, Vogelsang E, Leptin M. Cadherin switching during the formation and differentiation of the Drosophila mesoderm - implications for epithelial-to-mesenchymal transitions. J Cell Sci 2014; 127:1511-22. [PMID: 24496448 DOI: 10.1242/jcs.139485] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Epithelial-to-mesenchymal transition (EMT) is typically accompanied by downregulation of epithelial (E-) cadherin, and is often additionally accompanied by upregulation of a mesenchymal or neuronal (N-) cadherin. Snail represses transcription of the E-cadherin gene both during normal development and during tumour spreading. The formation of the mesodermal germ layer in Drosophila, considered a paradigm of a developmental EMT, is associated with Snail-mediated repression of E-cadherin and the upregulation of N-cadherin. By using genetic manipulation to remove or overexpress the cadherins, we show here that the complementarity of cadherin expression is not necessary for the segregation or the dispersal of the mesodermal germ layer in Drosophila. However, we discover different effects of E- and N-cadherin on the differentiation of subsets of mesodermal derivatives, which depend on Wingless signalling from the ectoderm, indicating differing abilities of E- and N-cadherin to bind to and sequester the common junctional and signalling effector β-catenin. These results suggest that the downregulation of E-cadherin in the mesoderm might be required to facilitate optimal levels of Wingless signalling.
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Affiliation(s)
- Gritt Schäfer
- Institute of Genetics, University of Cologne, Zülpicher Strasse 47a, 50674 Cologne, Germany
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41
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Wakayama N, Katow T, Katow H. Characterization and Endocytic Internalization of Epith-2 Cell Surface Glycoprotein during the Epithelial-to-Mesenchymal Transition in Sea Urchin Embryos. Front Endocrinol (Lausanne) 2013; 4:112. [PMID: 24009602 PMCID: PMC3757445 DOI: 10.3389/fendo.2013.00112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/14/2013] [Indexed: 01/25/2023] Open
Abstract
The epithelial cells of the sea urchin Hemicentrotus pulcherrimus embryo express an Epith-2, uncharacterized glycoprotein, on the lateral surface. Here, we describe internalization of Epith-2 during mesenchyme formation through the epithelial-to-mesenchymal transition (EMT). Epith-2 was first expressed on the entire egg surface soon after fertilization and on the blastomeres until the 4-cell stage, but was localized to the lateral surface of epithelial cells at and after the 16-cell stage throughout the later developmental period. However, primary mesenchyme cells (PMC) and secondary mesenchyme cells (SMC) that ingress by EMT lost Epith-2 from their cell surface by endocytosis during dissociation from the epithelium, which was associated with the appearance of cytoplasmic Epith-2 dots. The cytoplasmic Epith-2 retained a similar relative molecular mass to that of the cell surface immediately after ingression through the early period of the spreading to single cells. Then, Epith-2 was completely lost from the cytoplasm. Tyrosine residues of Epith-2 were phosphorylated. The endocytic retraction of Epith-2 was inhibited by herbimycin A (HA), a protein tyrosine kinase (PTK) inhibitor, and suramin, a growth factor receptor (GFR) inhibitor, suggesting the involvement of the GFR/PTK (GP) signaling pathway. These two GP inhibitors also inhibited PMC and SMC spreading to individual cells after ingression, but the dissociation of PMC and SMC from the epithelium was not inhibited. In suramin-treated embryos, dissociated mesenchyme cells migrated partially by retaining their epithelial morphology. In HA-treated embryos, no mesenchyme cells migrated. Thus, the EMT occurs in relation to internalization of Epith-2 from presumptive PMC and SMC.
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Affiliation(s)
- Norio Wakayama
- Research Center for Marine Biology, Tohoku University, Aomori, Aomori, Japan
| | - Tomoko Katow
- Research Center for Marine Biology, Tohoku University, Aomori, Aomori, Japan
| | - Hideki Katow
- Research Center for Marine Biology, Tohoku University, Aomori, Aomori, Japan
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Green SA, Norris RP, Terasaki M, Lowe CJ. FGF signaling induces mesoderm in the hemichordate Saccoglossus kowalevskii. Development 2013; 140:1024-33. [PMID: 23344709 DOI: 10.1242/dev.083790] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
FGFs act in vertebrate mesoderm induction and also play key roles in early mesoderm formation in ascidians and amphioxus. However, in sea urchins initial characterizations of FGF function do not support a role in early mesoderm induction, making the ancestral roles of FGF signaling and mechanisms of mesoderm specification in deuterostomes unclear. In order to better characterize the evolution of mesoderm formation, we have examined the role of FGF signaling during mesoderm development in Saccoglossus kowalevskii, an experimentally tractable representative of hemichordates. We report the expression of an FGF ligand, fgf8/17/18, in ectoderm overlying sites of mesoderm specification within the archenteron endomesoderm. Embryological experiments demonstrate that mesoderm induction in the archenteron requires contact with ectoderm, and loss-of-function experiments indicate that both FGF ligand and receptor are necessary for mesoderm specification. fgf8/17/18 gain-of-function experiments establish that FGF8/17/18 is sufficient to induce mesoderm in adjacent endomesoderm. These experiments suggest that FGF signaling is necessary from the earliest stages of mesoderm specification and is required for all mesoderm development. Furthermore, they suggest that the archenteron is competent to form mesoderm or endoderm, and that FGF signaling from the ectoderm defines the location and amount of mesoderm. When considered in a comparative context, these data support a phylogenetically broad requirement for FGF8/17/18 signaling in mesoderm specification and suggest that FGF signaling played an ancestral role in deuterostome mesoderm formation.
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Affiliation(s)
- Stephen A Green
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA.
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Kume K, Haraguchi M, Hijioka H, Ishida T, Miyawaki A, Nakamura N, Ozawa M. The transcription factor Snail enhanced the degradation of E-cadherin and desmoglein 2 in oral squamous cell carcinoma cells. Biochem Biophys Res Commun 2012; 430:889-94. [PMID: 23261431 DOI: 10.1016/j.bbrc.2012.12.060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 12/12/2012] [Indexed: 12/14/2022]
Abstract
Epithelial-mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell-cell junctions and cell polarity as well as the acquisition of migratory and invasive properties. However, the precise molecular events that initiate this complex EMT process are poorly understood. Snail is a regulator of EMT that represses E-cadherin transcription through its interaction with proximal E-boxes in the promoter region of target genes. To investigate the role of Snail in EMT, we generated stable Snail transfectants using the oral squamous cell carcinoma cell line HSC-4 (Snail/HSC-4). Snail/HSC-4 cells had a spindle-shaped mesenchymal morphology, and enhanced migration and invasiveness relative to control cells. Consistent with these EMT changes, the downregulation of epithelial marker proteins, E-cadherin and desmoglein 2, and the upregulation of mesenchymal marker proteins, vimentin and N-cadherin were detected. Despite these observations, the mRNA levels of E-cadherin and desmoglein 2 did not decrease significantly. Although E-cadherin and desmoglein 2 proteins were stable in parental HSC-4 cells, these proteins were rapidly degraded in Snail/HSC-4 cells. The degradation of E-cadherin, but not desmoglein 2, was inhibited by dynasore, an inhibitor of dynamin-dependent endocytosis. Therefore, in HSC-4 cells Snail regulates levels of these proteins both transcriptionally and post-translationally.
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Affiliation(s)
- Kenichi Kume
- Department of Biochemistry and Molecular Biology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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Abstract
Epithelial-mesenchymal transition (EMT) is a crucial, evolutionarily conserved process that occurs during development and is essential for shaping embryos. Also implicated in cancer, this morphological transition is executed through multiple mechanisms in different contexts, and studies suggest that the molecular programs governing EMT, albeit still enigmatic, are embedded within developmental programs that regulate specification and differentiation. As we review here, knowledge garnered from studies of EMT during gastrulation, neural crest delamination and heart formation have furthered our understanding of tumor progression and metastasis.
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Affiliation(s)
- Jormay Lim
- Institute of Molecular Cell Biology, ASTAR, 61 Biopolis Drive, Singapore
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Casanova JC, Travisano S, de la Pompa JL. Epithelial-to-mesenchymal transition in epicardium is independent of Snail1. Genesis 2012; 51:32-40. [PMID: 23097346 DOI: 10.1002/dvg.22353] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/15/2012] [Indexed: 11/07/2022]
Abstract
The epicardium is the outer epithelial covering the heart. This tissue undergoes an epithelial-to-mesenchymal transition (EMT) to generate mesenchymal epicardial-derived cells (EPDCs) that populate the extracellular matrix of the subepicardium and contribute to the development of the coronary vessels and cardiac interstitial cells. Although epicardial EMT plays a crucial role in heart development, the molecular regulation of this process is incompletely understood. Here we examined the possible role of the EMT regulator Snail1 in this process. Snail1 is expressed in the epicardium and EPDCs during mouse cardiac development. To determine the function of Snail1 in epicardial EMT, we deleted Snail1 in the epicardium using Wt1- and Tbx18-Cre drivers. Unexpectedly, epicardial-specific Snail1 mutants are viable and fertile and do not display any obvious morphological or functional cardiac abnormalities. Molecular analysis of these mice reveals that epicardial EMT occurs normally, and epicardial derivatives are established in these mutants. We conclude that Snail1 is not required for the initiation and progression of embryonic epicardial EMT.
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Hammond LM, Hofmann GE. Early developmental gene regulation in Strongylocentrotus purpuratus embryos in response to elevated CO₂ seawater conditions. ACTA ACUST UNITED AC 2012; 215:2445-54. [PMID: 22723484 DOI: 10.1242/jeb.058008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ocean acidification, or the increased uptake of CO(2) by the ocean due to elevated atmospheric CO(2) concentrations, may variably impact marine early life history stages, as they may be especially susceptible to changes in ocean chemistry. Investigating the regulatory mechanisms of early development in an environmental context, or ecological development, will contribute to increased understanding of potential organismal responses to such rapid, large-scale environmental changes. We examined transcript-level responses to elevated seawater CO(2) during gastrulation and the initiation of spiculogenesis, two crucial developmental processes in the purple sea urchin, Strongylocentrotus purpuratus. Embryos were reared at the current, accepted oceanic CO(2) concentration of 380 microatmospheres (μatm), and at the elevated levels of 1000 and 1350 μatm, simulating predictions for oceans and upwelling regions, respectively. The seven genes of interest comprised a subset of pathways in the primary mesenchyme cell gene regulatory network (PMC GRN) shown to be necessary for the regulation and execution of gastrulation and spiculogenesis. Of the seven genes, qPCR analysis indicated that elevated CO(2) concentrations only had a significant but subtle effect on two genes, one important for early embryo patterning, Wnt8, and the other an integral component in spiculogenesis and biomineralization, SM30b. Protein levels of another spicule matrix component, SM50, demonstrated significant variable responses to elevated CO(2). These data link the regulation of crucial early developmental processes with the environment that these embryos would be developing within, situating the study of organismal responses to ocean acidification in a developmental context.
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Affiliation(s)
- LaTisha M Hammond
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106-9620, USA.
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Yajima M, Wessel GM. Autonomy in specification of primordial germ cells and their passive translocation in the sea urchin. Development 2012; 139:3786-94. [PMID: 22991443 PMCID: PMC3445309 DOI: 10.1242/dev.082230] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2012] [Indexed: 01/22/2023]
Abstract
The process of germ line determination involves many conserved genes, yet is highly variable. Echinoderms are positioned at the base of Deuterostomia and are crucial to understanding these evolutionary transitions, yet the mechanism of germ line specification is not known in any member of the phyla. Here we demonstrate that small micromeres (SMics), which are formed at the fifth cell division of the sea urchin embryo, illustrate many typical features of primordial germ cell (PGC) specification. SMics autonomously express germ line genes in isolated culture, including selective Vasa protein accumulation and transcriptional activation of nanos; their descendants are passively displaced towards the animal pole by secondary mesenchyme cells and the elongating archenteron during gastrulation; Cadherin (G form) has an important role in their development and clustering phenotype; and a left/right integration into the future adult anlagen appears to be controlled by a late developmental mechanism. These results suggest that sea urchin SMics share many more characteristics typical of PGCs than previously thought, and imply a more widely conserved system of germ line development among metazoans.
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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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Lyons DC, Kaltenbach SL, McClay DR. Morphogenesis in sea urchin embryos: linking cellular events to gene regulatory network states. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:231-52. [PMID: 23801438 DOI: 10.1002/wdev.18] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gastrulation in the sea urchin begins with ingression of the primary mesenchyme cells (PMCs) at the vegetal pole of the embryo. After entering the blastocoel the PMCs migrate, form a syncitium, and synthesize the skeleton of the embryo. Several hours after the PMCs ingress the vegetal plate buckles to initiate invagination of the archenteron. That morphogenetic process occurs in several steps. The nonskeletogenic cells produce the initial inbending of the vegetal plate. Endoderm cells then rearrange and extend the length of the gut across the blastocoel to a target near the animal pole. Finally, cells that will form part of the midgut and hindgut are added to complete gastrulation. Later, the stomodeum invaginates from the oral ectoderm and fuses with the foregut to complete the archenteron. In advance of, and during these morphogenetic events, an increasingly complex input of transcription factors controls the specification and the cell biological events that conduct the gastrulation movements.
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Affiliation(s)
- Deirdre C Lyons
- Department of Biology, French Family Science Center, Duke University, Durham, NC, USA
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Rafiq K, Cheers MS, Ettensohn CA. The genomic regulatory control of skeletal morphogenesis in the sea urchin. Development 2011; 139:579-90. [PMID: 22190640 DOI: 10.1242/dev.073049] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A central challenge of developmental and evolutionary biology is to understand how anatomy is encoded in the genome. Elucidating the genetic mechanisms that control the development of specific anatomical features will require the analysis of model morphogenetic processes and an integration of biological information at genomic, cellular and tissue levels. The formation of the endoskeleton of the sea urchin embryo is a powerful experimental system for developing such an integrated view of the genomic regulatory control of morphogenesis. The dynamic cellular behaviors that underlie skeletogenesis are well understood and a complex transcriptional gene regulatory network (GRN) that underlies the specification of embryonic skeletogenic cells (primary mesenchyme cells, PMCs) has recently been elucidated. Here, we link the PMC specification GRN to genes that directly control skeletal morphogenesis. We identify new gene products that play a proximate role in skeletal morphogenesis and uncover transcriptional regulatory inputs into many of these genes. Our work extends the importance of the PMC GRN as a model developmental GRN and establishes a unique picture of the genomic regulatory control of a major morphogenetic process. Furthermore, because echinoderms exhibit diverse programs of skeletal development, the newly expanded sea urchin skeletogenic GRN will provide a foundation for comparative studies that explore the relationship between GRN evolution and morphological evolution.
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Affiliation(s)
- Kiran Rafiq
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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Wu CY, Jhingory S, Taneyhill LA. The tight junction scaffolding protein cingulin regulates neural crest cell migration. Dev Dyn 2011; 240:2309-23. [PMID: 21905165 DOI: 10.1002/dvdy.22735] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2011] [Indexed: 01/11/2023] Open
Abstract
Neural crest cells give rise to a diverse range of structures during vertebrate development. These cells initially exist in the dorsal neuroepithelium and subsequently acquire the capacity to migrate. Although studies have documented the importance of adherens junctions in regulating neural crest cell migration, little attention has been paid to tight junctions during this process. We now identify the tight junction protein cingulin as a key regulator of neural crest migration. Cingulin knock-down increases the migratory neural crest cell domain, which is correlated with a disruption of the neural tube basal lamina. Overexpression of cingulin also augments neural crest cell migration and is associated with similar basal lamina changes and an expansion of the premigratory neural crest population. Cingulin overexpression causes aberrant ventrolateral neuroepithelial cell delamination, which is linked to laminin loss and a decrease in RhoA. Together, our results highlight a novel function for cingulin in the neural crest.
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Affiliation(s)
- Chyong-Yi Wu
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, USA
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