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Clark-Hachtel CM, Hibshman JD, De Buysscher T, Stair ER, Hicks LM, Goldstein B. The tardigrade Hypsibius exemplaris dramatically upregulates DNA repair pathway genes in response to ionizing radiation. Curr Biol 2024; 34:1819-1830.e6. [PMID: 38614079 PMCID: PMC11078613 DOI: 10.1016/j.cub.2024.03.019] [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] [Received: 09/29/2023] [Revised: 01/19/2024] [Accepted: 03/13/2024] [Indexed: 04/15/2024]
Abstract
Tardigrades can survive remarkable doses of ionizing radiation, up to about 1,000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but the damage is repaired. We show that this species has a specific and robust response to ionizing radiation: irradiation induces a rapid upregulation of many DNA repair genes. This upregulation is unexpectedly extreme-making some DNA repair transcripts among the most abundant transcripts in the animal. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is important in vivo for tardigrade radiation tolerance. We hypothesize that the tardigrades' ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
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Affiliation(s)
- Courtney M Clark-Hachtel
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Biology Department, The University of North Carolina at Asheville, Asheville, NC 28804, USA.
| | - Jonathan D Hibshman
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tristan De Buysscher
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Bioinformatics & Analytics Research Collaborative, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Evan R Stair
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Leslie M Hicks
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bob Goldstein
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Quiroga-Artigas G, Moriel-Carretero M. Storage cell proliferation during somatic growth establishes that tardigrades are not eutelic organisms. Biol Open 2024; 13:bio060299. [PMID: 38411464 PMCID: PMC10924213 DOI: 10.1242/bio.060299] [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] [Received: 01/02/2024] [Accepted: 01/22/2024] [Indexed: 02/28/2024] Open
Abstract
Tardigrades, microscopic ecdysozoans known for extreme environment resilience, were traditionally believed to maintain a constant cell number after completing embryonic development, a phenomenon termed eutely. However, sporadic reports of dividing cells have raised questions about this assumption. In this study, we explored tardigrade post-embryonic cell proliferation using the model species Hypsibius exemplaris. Comparing hatchlings to adults, we observed an increase in the number of storage cells, responsible for nutrient storage. We monitored cell proliferation via 5-ethynyl-2'-deoxyuridine (EdU) incorporation, revealing large numbers of EdU+ storage cells during growth, which starvation halted. EdU incorporation associated with molting, a vital post-embryonic development process involving cuticle renewal for further growth. Notably, DNA replication inhibition strongly reduced EdU+ cell numbers and caused molting-related fatalities. Our study is the first to demonstrate using molecular approaches that storage cells actively proliferate during tardigrade post-embryonic development, providing a comprehensive insight into replication events throughout their somatic growth. Additionally, our data underscore the significance of proper DNA replication in tardigrade molting and survival. This work definitely establishes that tardigrades are not eutelic, and offers insights into cell cycle regulation, replication stress, and DNA damage management in these remarkable creatures as genetic manipulation techniques emerge within the field.
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Affiliation(s)
- Gonzalo Quiroga-Artigas
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, 34293 Montpellier CEDEX 05, France
| | - María Moriel-Carretero
- Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, 34293 Montpellier CEDEX 05, France
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Heikes KL, Goldstein B. Expression patterns of FGF and BMP pathway genes in the tardigrade Hypsibius exemplaris. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577774. [PMID: 38352320 PMCID: PMC10862696 DOI: 10.1101/2024.01.29.577774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
A small number of conserved signaling pathways regulate development of most animals, yet we do not know where these pathways are deployed in most embryos. This includes tardigrades, a phylum with a unique body shape. We examined expression patterns of components of the BMP and FGF signaling pathways during embryonic segmentation and mesoderm development of the tardigrade Hypsibius exemplaris. Among the patterns examined, we found that an FGF ligand gene is expressed in ectodermal segment posteriors and an FGF receptor gene is expressed in underlying endomesodermal pouches, suggesting possible FGF signaling between these developing germ layers. We found that a BMP ligand gene is expressed in lateral ectoderm and dorsolateral bands along segment posteriors, while the BMP antagonist Sog gene is expressed in lateral ectoderm and also in a subset of endomesodermal cells, suggesting a possible role of BMP signaling in dorsal-ventral patterning of lateral ectoderm. In combination with known roles of these pathways during development of common model systems, we developed hypotheses for how the BMP and FGF pathways might regulate embryo segmentation and mesoderm formation of the tardigrade H. exemplaris. These results identify the expression patterns of genes from two conserved signaling pathways for the first time in the tardigrade phylum.
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Affiliation(s)
- Kira L. Heikes
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Bob Goldstein
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Tanaka A, Kunieda T. Considerations on the TardiVec-based analyses of tissue specificity and desiccation-induced supramolecular structure of target proteins. Proc Natl Acad Sci U S A 2023; 120:e2312563120. [PMID: 37983508 PMCID: PMC10691217 DOI: 10.1073/pnas.2312563120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023] Open
Affiliation(s)
- Akihiro Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0033, Japan
| | - Takekazu Kunieda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0033, Japan
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Smith FW, Game M, Mapalo MA, Chavarria RA, Harrison TR, Janssen R. Developmental and genomic insight into the origin of the tardigrade body plan. Evol Dev 2023. [PMID: 37721221 DOI: 10.1111/ede.12457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023]
Abstract
Tardigrada is an ancient lineage of miniaturized animals. As an outgroup of the well-studied Arthropoda and Onychophora, studies of tardigrades hold the potential to reveal important insights into body plan evolution in Panarthropoda. Previous studies have revealed interesting facets of tardigrade development and genomics that suggest that a highly compact body plan is a derived condition of this lineage, rather than it representing an ancestral state of Panarthropoda. This conclusion was based on studies of several species from Eutardigrada. We review these studies and expand on them by analyzing the publicly available genome and transcriptome assemblies of Echiniscus testudo, a representative of Heterotardigrada. These new analyses allow us to phylogenetically reconstruct important features of genome evolution in Tardigrada. We use available data from tardigrades to interrogate several recent models of body plan evolution in Panarthropoda. Although anterior segments of panarthropods are highly diverse in terms of anatomy and development, both within individuals and between species, we conclude that a simple one-to-one alignment of anterior segments across Panarthropoda is the best available model of segmental homology. In addition to providing important insight into body plan diversification within Panarthropoda, we speculate that studies of tardigrades may reveal generalizable pathways to miniaturization.
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Affiliation(s)
- Frank W Smith
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Mandy Game
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Marc A Mapalo
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Raul A Chavarria
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Taylor R Harrison
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Uppsala, Sweden
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Heikes KL, Game M, Smith FW, Goldstein B. The embryonic origin of primordial germ cells in the tardigrade Hypsibius exemplaris. Dev Biol 2023; 497:42-58. [PMID: 36893882 DOI: 10.1016/j.ydbio.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 02/16/2023] [Accepted: 02/26/2023] [Indexed: 03/09/2023]
Abstract
Primordial germ cells (PGCs) give rise to gametes - cells necessary for the propagation and fertility of diverse organisms. Current understanding of PGC development is limited to the small number of organisms whose PGCs have been identified and studied. Expanding the field to include little-studied taxa and emerging model organisms is important to understand the full breadth of the evolution of PGC development. In the phylum Tardigrada, no early cell lineages have been identified to date using molecular markers. This includes the PGC lineage. Here, we describe PGC development in the model tardigrade Hypsibius exemplaris. The four earliest-internalizing cells (EICs) exhibit PGC-like behavior and nuclear morphology. The location of the EICs is enriched for mRNAs of conserved PGC markers wiwi1 (water bear piwi 1) and vasa. At early stages, both wiwi1 and vasa mRNAs are detectable uniformly in embryos, which suggests that these mRNAs do not serve as localized determinants for PGC specification. Only later are wiwi1 and vasa enriched in the EICs. Finally, we traced the cells that give rise to the four PGCs. Our results reveal the embryonic origin of the PGCs of H. exemplaris and provide the first molecular characterization of an early cell lineage in the tardigrade phylum. We anticipate that these observations will serve as a basis for characterizing the mechanisms of PGC development in this animal.
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Affiliation(s)
- Kira L Heikes
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mandy Game
- Biology Department, University of North Florida, Jacksonville, FL, USA
| | - Frank W Smith
- Biology Department, University of North Florida, Jacksonville, FL, USA
| | - Bob Goldstein
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Thompson MA, De-Souza EA. A Year at the Forefront of Proteostasis and Aging. Biol Open 2023; 12:bio059750. [PMID: 36794708 PMCID: PMC9943145 DOI: 10.1242/bio.059750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
During aging, animals experience a decline in proteostasis activity, including loss of stress-response activation, culminating in the accumulation of misfolded proteins and toxic aggregates, which are causal in the onset of some chronic diseases. Finding genetic and pharmaceutical treatments that can increase organismal proteostasis and lengthen life is an ongoing goal of current research. The regulation of stress responses by cell non-autonomous mechanisms appears to be a potent way to impact organismal healthspan. In this Review, we cover recent findings in the intersection of proteostasis and aging, with a special focus on articles and preprints published between November 2021 and October 2022. A significant number of papers published during this time increased our understanding of how cells communicate with each other during proteotoxic stress. Finally, we also draw attention to emerging datasets that can be explored to generate new hypotheses that explain age-related proteostasis collapse.
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Affiliation(s)
- Maximilian A. Thompson
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Evandro A. De-Souza
- Neurobiology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
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Heikes KL, Game M, Smith FW, Goldstein B. The Embryonic Origin of Primordial Germ Cells in the Tardigrade Hypsibius exemplaris. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.02.522500. [PMID: 36824831 PMCID: PMC9948961 DOI: 10.1101/2023.01.02.522500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Primordial germ cells (PGCs) give rise to gametes â€" cells necessary for the propagation and fertility of diverse organisms. Current understanding of PGC development is limited to the small number of organisms whose PGCs have been identified and studied. Expanding the field to include little-studied taxa and emerging model organisms is important to understand the full breadth of the evolution of PGC development. In the phylum Tardigrada, no early cell lineages have been identified to date using molecular markers. This includes the PGC lineage. Here, we describe PGC development in the model tardigrade Hypsibius exemplaris . The four earliest-internalizing cells (EICs) exhibit PGC-like behavior and nuclear morphology. The location of the EICs is enriched for mRNAs of conserved PGC markers wiwi1 (water bear piwi 1) and vasa . At early stages, both wiwi1 and vasa mRNAs are detectable uniformly in embryos, which suggests that these mRNAs do not serve as localized determinants for PGC specification. Only later are wiwi1 and vasa enriched in the EICs. Finally, we traced the cells that give rise to the four PGCs. Our results reveal the embryonic origin of the PGCs of H. exemplaris and provide the first molecular characterization of an early cell lineage in the tardigrade phylum. We anticipate that these observations will serve as a basis for characterizing the mechanisms of PGC development in this animal.
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Affiliation(s)
- Kira L. Heikes
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mandy Game
- Biology Department, University of North Florida, Jacksonville, FL, USA
| | - Frank W. Smith
- Biology Department, University of North Florida, Jacksonville, FL, USA
| | - Bob Goldstein
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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9
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Goldstein B. Tardigrades. Nat Methods 2022; 19:904-905. [PMID: 35927483 DOI: 10.1038/s41592-022-01573-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bob Goldstein
- Department of Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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