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Sugiura K, Yoshida Y, Hayashi K, Arakawa K, Kunieda T, Matsumoto M. Sexual dimorphism in the tardigrade Paramacrobiotus metropolitanus transcriptome. ZOOLOGICAL LETTERS 2024; 10:11. [PMID: 38902818 PMCID: PMC11191345 DOI: 10.1186/s40851-024-00233-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/14/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND In gonochoristic animals, the sex determination pathway induces different morphological and behavioral features that can be observed between sexes, a condition known as sexual dimorphism. While many components of this sex differentiation cascade show high levels of diversity, factors such as the Doublesex-Mab-3-Related Transcription factor (DMRT) are widely conserved across animal taxa. Species of the phylum Tardigrada exhibit remarkable diversity in morphology and behavior between sexes, suggesting a pathway regulating this dimorphism. Despite the wealth of genomic and zoological knowledge accumulated in recent studies, the sexual differences in tardigrades genomes have not been identified. In the present study, we focused on the gonochoristic species Paramacrobiotus metropolitanus and employed omics analyses to unravel the molecular basis of sexual dimorphism. RESULTS Transcriptome analysis between sex-identified specimens revealed numerous differentially expressed genes, of which approximately 2,000 male-biased genes were focused on 29 non-male-specific genomic loci. From these regions, we identified two Macrobiotidae family specific DMRT paralogs, which were significantly upregulated in males and lacked sex specific splicing variants. Furthermore, phylogenetic analysis indicated all tardigrade genomes lack the doublesex ortholog, suggesting doublesex emerged after the divergence of Tardigrada. In contrast to sex-specific expression, no evidence of genomic differences between the sexes was found. We also identified several anhydrobiosis genes that exhibit sex-biased expression, suggesting a possible mechanism for protection of sex-specific tissues against extreme stress. CONCLUSIONS This study provides a comprehensive analysis for analyzing the genetic differences between sexes in tardigrades. The existence of male-biased, but not male-specific, genomic loci and identification of the family specific male-biased DMRT subfamily provides the foundation for understanding the sex determination cascade. In addition, sex-biased expression of several tardigrade-specific genes which are involved their stress tolerance suggests a potential role in protecting sex-specific tissue and gametes.
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Affiliation(s)
- Kenta Sugiura
- Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa, 223-8522, Japan
| | - Yuki Yoshida
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Kohei Hayashi
- Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa, 223-8522, Japan
| | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, 403-1 Nihonkoku, Daihoji, Tsuruoka, Yamagata, 997-0017, Japan
- Exploratory Research Center On Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Takekazu Kunieda
- Department of Biological Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
| | - Midori Matsumoto
- Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa, 223-8522, Japan.
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Galas S, Le Goff E, Cazevieille C, Tanaka A, Cuq P, Baghdiguian S, Kunieda T, Godefroy N, Richaud M. A comparative ultrastructure study of the tardigrade Ramazzottius varieornatus in the hydrated state, after desiccation and during the process of rehydration. PLoS One 2024; 19:e0302552. [PMID: 38843161 PMCID: PMC11156355 DOI: 10.1371/journal.pone.0302552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/07/2024] [Indexed: 06/09/2024] Open
Abstract
Tardigrades can survive hostile environments such as desiccation by adopting a state of anhydrobiosis. Numerous tardigrade species have been described thus far, and recent genome and transcriptome analyses revealed that several distinct strategies were employed to cope with harsh environments depending on the evolutionary lineages. Detailed analyses at the cellular and subcellular levels are essential to complete these data. In this work, we analyzed a tardigrade species that can withstand rapid dehydration, Ramazzottius varieornatus. Surprisingly, we noted an absence of the anhydrobiotic-specific extracellular structure previously described for the Hypsibius exemplaris species. Both Ramazzottius varieornatus and Hypsibius exemplaris belong to the same evolutionary class of Eutardigrada. Nevertheless, our observations reveal discrepancies in the anhydrobiotic structures correlated with the variation in the anhydrobiotic mechanisms.
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Affiliation(s)
- Simon Galas
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Emilie Le Goff
- ISEM, University of Montpellier, CNRS, IRD, Montpellier, France
| | | | - Akihiro Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Pierre Cuq
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | | | - Takekazu Kunieda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Nelly Godefroy
- ISEM, University of Montpellier, CNRS, IRD, Montpellier, France
| | - Myriam Richaud
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
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In vivo expression vector derived from anhydrobiotic tardigrade genome enables live imaging in Eutardigrada. Proc Natl Acad Sci U S A 2023; 120:e2216739120. [PMID: 36693101 PMCID: PMC9945988 DOI: 10.1073/pnas.2216739120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Water is essential for life, but anhydrobiotic tardigrades can survive almost complete dehydration. Anhydrobiosis has been a biological enigma for more than a century with respect to how organisms sustain life without water, but the few choices of genetic toolkits available in tardigrade research have been a challenging circumstance. Here, we report the development of an in vivo expression system for tardigrades. This transient transgenic technique is based on a plasmid vector (TardiVec) with promoters that originated from an anhydrobiotic tardigrade Ramazzottius varieornatus. It enables the introduction of GFP-fused proteins and genetically encoded indicators such as the Ca2+ indicator GCaMP into tardigrade cells; consequently, the dynamics of proteins and cells in tardigrades may be observed by fluorescence live imaging. This system is applicable for several tardigrades in the class Eutardigrada: the promoters of anhydrobiosis-related genes showed tissue-specific expression in this work. Surprisingly, promoters functioned similarly between multiple species, even for species with different modes of expression of anhydrobiosis-related genes, such as Hypsibius exemplaris, in which these genes are highly induced upon facing desiccation, and Thulinius ruffoi, which lacks anhydrobiotic capability. These results suggest that the highly dynamic expression changes in desiccation-induced species are regulated in trans. Tissue-specific expression of tardigrade-unique unstructured proteins also suggests differing anhydrobiosis machinery depending on the cell types. We believe that tardigrade transgenic technology opens up various experimental possibilities in tardigrade research, especially to explore anhydrobiosis mechanisms.
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