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Atajanova T, Kang EM, Postnikova A, Price AL, Doerr S, Du M, Ugenti A, Ragkousi K. Lateral cell polarization drives organization of epithelia in sea anemone embryos and embryonic cell aggregates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.07.588493. [PMID: 38645007 PMCID: PMC11030385 DOI: 10.1101/2024.04.07.588493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
One of the first organizing processes during animal development is the assembly of embryonic cells into epithelia. In certain animals, including Hydra and sea anemones, epithelia also emerge when cells from dissociated tissues are aggregated back together. Although cell adhesion is required to keep cells together, it is not clear whether cell polarization plays a role as epithelia emerge from disordered aggregates. Here, we demonstrate that lateral cell polarization is essential for epithelial organization in both embryos and aggregates of the sea anemone Nematostella vectensis. Specifically, knock down of the lateral polarity protein Lgl disrupts epithelia in developing embryos and impairs the capacity of dissociated cells to epithelialize from aggregates. Cells in lgl mutant epithelia lose their columnar shape and have mispositioned mitotic spindles and ciliary basal bodies. Together, our data suggest that in Nematostella, Lgl is required to establish lateral cell polarity and position cytoskeletal organelles in cells of embryos and aggregates during de novo epithelial organization.
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Affiliation(s)
- Tavus Atajanova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | | | - Anna Postnikova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | | | - Sophia Doerr
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Michael Du
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Alicia Ugenti
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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Nematostella vectensis, an Emerging Model for Deciphering the Molecular and Cellular Mechanisms Underlying Whole-Body Regeneration. Cells 2021; 10:cells10102692. [PMID: 34685672 PMCID: PMC8534814 DOI: 10.3390/cells10102692] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/18/2022] Open
Abstract
The capacity to regenerate lost or injured body parts is a widespread feature within metazoans and has intrigued scientists for centuries. One of the most extreme types of regeneration is the so-called whole body regenerative capacity, which enables regeneration of fully functional organisms from isolated body parts. While not exclusive to this habitat, whole body regeneration is widespread in aquatic/marine invertebrates. Over the past decade, new whole-body research models have emerged that complement the historical models Hydra and planarians. Among these, the sea anemone Nematostella vectensis has attracted increasing interest in regard to deciphering the cellular and molecular mechanisms underlying the whole-body regeneration process. This manuscript will present an overview of the biological features of this anthozoan cnidarian as well as the available tools and resources that have been developed by the scientific community studying Nematostella. I will further review our current understanding of the cellular and molecular mechanisms underlying whole-body regeneration in this marine organism, with emphasis on how comparing embryonic development and regeneration in the same organism provides insight into regeneration specific elements.
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Ectopic activation of GABA B receptors inhibits neurogenesis and metamorphosis in the cnidarian Nematostella vectensis. Nat Ecol Evol 2020; 5:111-121. [PMID: 33168995 DOI: 10.1038/s41559-020-01338-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 09/29/2020] [Indexed: 01/22/2023]
Abstract
The metabotropic gamma-aminobutyric acid B receptor (GABABR) is a G protein-coupled receptor that mediates neuronal inhibition by the neurotransmitter GABA. While GABABR-mediated signalling has been suggested to play central roles in neuronal differentiation and proliferation across evolution, it has mostly been studied in the mammalian brain. Here, we demonstrate that ectopic activation of GABABR signalling affects neurogenic functions in the sea anemone Nematostella vectensis. We identified four putative Nematostella GABABR homologues presenting conserved three-dimensional extracellular domains and residues needed for binding GABA and the GABABR agonist baclofen. Moreover, sustained activation of GABABR signalling reversibly arrests the critical metamorphosis transition from planktonic larva to sessile polyp life stage. To understand the processes that underlie the developmental arrest, we combined transcriptomic and spatial analyses of control and baclofen-treated larvae. Our findings reveal that the cnidarian neurogenic programme is arrested following the addition of baclofen to developing larvae. Specifically, neuron development and neurite extension were inhibited, resulting in an underdeveloped and less organized nervous system and downregulation of proneural factors including NvSoxB(2), NvNeuroD1 and NvElav1. Our results thus point to an evolutionarily conserved function of GABABR in neurogenesis regulation and shed light on early cnidarian development.
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Chen CY, McKinney SA, Ellington LR, Gibson MC. Hedgehog signaling is required for endomesodermal patterning and germ cell development in the sea anemone Nematostella vectensis. eLife 2020; 9:e54573. [PMID: 32969790 PMCID: PMC7515634 DOI: 10.7554/elife.54573] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 09/05/2020] [Indexed: 12/27/2022] Open
Abstract
Two distinct mechanisms for primordial germ cell (PGC) specification are observed within Bilatera: early determination by maternal factors or late induction by zygotic cues. Here we investigate the molecular basis for PGC specification in Nematostella, a representative pre-bilaterian animal where PGCs arise as paired endomesodermal cell clusters during early development. We first present evidence that the putative PGCs delaminate from the endomesoderm upon feeding, migrate into the gonad primordia, and mature into germ cells. We then show that the PGC clusters arise at the interface between hedgehog1 and patched domains in the developing mesenteries and use gene knockdown, knockout and inhibitor experiments to demonstrate that Hh signaling is required for both PGC specification and general endomesodermal patterning. These results provide evidence that the Nematostella germline is specified by inductive signals rather than maternal factors, and support the existence of zygotically-induced PGCs in the eumetazoan common ancestor.
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Affiliation(s)
- Cheng-Yi Chen
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Sean A McKinney
- Stowers Institute for Medical ResearchKansas CityUnited States
| | | | - Matthew C Gibson
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Anatomy and Cell Biology, The University of Kansas School of MedicineKansas CityUnited States
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He S, Del Viso F, Chen CY, Ikmi A, Kroesen AE, Gibson MC. An axial Hox code controls tissue segmentation and body patterning in Nematostella vectensis. Science 2018; 361:1377-1380. [PMID: 30262503 DOI: 10.1126/science.aar8384] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 08/09/2018] [Indexed: 11/02/2022]
Abstract
Hox genes encode conserved developmental transcription factors that govern anterior-posterior (A-P) pattering in diverse bilaterian animals, which display bilateral symmetry. Although Hox genes are also present within Cnidaria, these simple animals lack a definitive A-P axis, leaving it unclear how and when a functionally integrated Hox code arose during evolution. We used short hairpin RNA (shRNA)-mediated knockdown and CRISPR-Cas9 mutagenesis to demonstrate that a Hox-Gbx network controls radial segmentation of the larval endoderm during development of the sea anemone Nematostella vectensis. Loss of Hox-Gbx activity also elicits marked defects in tentacle patterning along the directive (orthogonal) axis of primary polyps. On the basis of our results, we propose that an axial Hox code may have controlled body patterning and tissue segmentation before the evolution of the bilaterian A-P axis.
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Affiliation(s)
- Shuonan He
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | | | - Cheng-Yi Chen
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Aissam Ikmi
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA.,Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Amanda E Kroesen
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Matthew C Gibson
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA. .,Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, KS 66160, USA
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Intraspecific variation in oxidative stress tolerance in a model cnidarian: Differences in peroxide sensitivity between and within populations of Nematostella vectensis. PLoS One 2018; 13:e0188265. [PMID: 29373572 PMCID: PMC5786289 DOI: 10.1371/journal.pone.0188265] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/05/2017] [Indexed: 12/27/2022] Open
Abstract
Nematostella vectensis is a member of the phylum Cnidaria, a lineage that includes anemones, corals, hydras, and jellyfishes. This estuarine anemone is an excellent model system for investigating the evolution of stress tolerance because it is easy to collect in its natural habitat and to culture in the laboratory, and it has a sequenced genome. Additionally, there is evidence of local adaptation to environmental stress in different N. vectensis populations, and abundant protein-coding polymorphisms have been identified, including polymorphisms in proteins that are implicated in stress responses. N. vectensis can tolerate a wide range of environmental parameters, and has recently been shown to have substantial intraspecific variation in temperature preference. We investigated whether different clonal lines of anemones also exhibit differential tolerance to oxidative stress. N. vectensis populations are continually exposed to reactive oxygen species (ROS) generated during cellular metabolism and by other environmental factors. Fifteen clonal lines of N. vectensis collected from four different estuaries were exposed to hydrogen peroxide. Pronounced differences in survival and regeneration were apparent between clonal lines collected from Meadowlands, NJ, Baruch, SC, and Kingsport, NS, as well as among 12 clonal lines collected from a single Cape Cod marsh. To our knowledge, this is the first example of intraspecific variability in oxidative stress resistance in cnidarians or in any marine animal. As oxidative stress often accompanies heat stress in marine organisms, resistance to oxidative stress could strongly influence survival in warming oceans. For example, while elevated temperatures trigger bleaching in corals, oxidative stress is thought to be the proximal trigger of bleaching at the cellular level.
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Fischer AHL, Tulin S, Fredman D, Smith J. Employing BAC-reporter constructs in the sea anemone Nematostella vectensis. Integr Comp Biol 2013; 53:832-46. [PMID: 23956207 DOI: 10.1093/icb/ict091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Changes in the expression and function of genes drive evolutionary change. Comparing how genes are regulated in different species is therefore becoming an important part of evo-devo studies. A key tool for investigating the regulation of genes is represented by bacterial artificial chromosomes (BAC)-reporter constructs. BACs are large insert libraries, often >100 kb, which thus capture the genomic sequences surrounding a gene of interest, including all, or nearly all, of the elements underpinning regulation. Recombinant BACs, containing a reporter gene in place of the endogenous coding sequence of genes, can be utilized to drive the expression of reporter genes under the regulatory control of the gene of interest while still embedded within its genomic context. Systematic deletions within the BAC-reporter construct can be used to identify the minimal reporter in an unbiased way, avoiding the risk of overlooking regulatory elements that may be many kilobases away from the transcription start-site. Nematostella vectensis (Edwardsiidae, Anthozoa, Cnidaria) has become an important model in regenerative biology, ecology, and especially in studies of evo-devo and gene-regulatory networks due to its interesting phylogenetic position and amenability to molecular techniques. The increasing interest in this rising model system also led to a demand for methods that can be used to study the regulation of genes in Nematostella. Here, we present our progress in employing BAC-reporter constructs to visualize gene-expression in Nematostella. Using a new Nematostella-specific recombination cassette, we made nine different BAC-reporter constructs. Although five BAC recombinants gave variable effects, three constructs, namely Nv-bra:eGFP::L10 BAC, Nv-dpp:eGFP::L10 BAC, and Nv-grm:eGFP::L10 BAC delivered promising results. We show that these three constructs express the reporter gene eGFP in 10.4-17.2% of all analyzed larvae, out of which 26.2-41.9% express GFP in a mosaic fashion within the expected domain. In addition to the expression within the known domains, we also observed cases of misexpression of eGFP and examples that could represent actual expression outside the described domain. Furthermore, we deep-sequenced and assembled five different BACs containing Nv-chordin, Nv-foxa, Nv-dpp, Nv-wnta, and Nv-wnt1, to improve assembly around these genes. The use of BAC-reporter constructs will foster cis-regulatory analyses in Nematostella and thus help to improve our understanding of the regulatory network in this cnidarian system. Ultimately, this will advance the comparison of gene-regulation across species and lead to a much better understanding of evolutionary changes and novelties.
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Affiliation(s)
- Antje H L Fischer
- *Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA; Department of Molecular Evolution and Development, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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Genikhovich G, Technau U. The starlet sea anemone Nematostella vectensis: an anthozoan model organism for studies in comparative genomics and functional evolutionary developmental biology. Cold Spring Harb Protoc 2010; 2009:pdb.emo129. [PMID: 20147257 DOI: 10.1101/pdb.emo129] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Grigory Genikhovich
- Department for Molecular Evolution and Development, Center for Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, 1090 Wien, Austria
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