Transcriptome analysis of the extremophile tardigrade Hypsibius exemplaris exposed to the DNA-damaging agent bleomycin
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ABSTRACT:
ORGANISM(S): Hypsibius exemplaris
PROVIDER: GSE168917 | GEO | 2024/05/07
REPOSITORIES: GEO
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Project description:Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 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 damage is repaired. We show that tardigrades have a specific and robust response to ionizing radiation: irradiation induces a rapid and dramatic upregulation of many DNA repair genes. 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 necessary for tardigrade radiation tolerance. Tardigrades’ ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
2024-04-12 | GSE253470 | GEO
Project description:Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 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 damage is repaired. We show that this tardigrade 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 for tardigrade radiation tolerance. We hypothesize that tardigrades’ ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
2024-04-12 | GSE240501 | GEO
Project description:Tardigrades can cope with adverse environmental conditions by turning into anhydrobiotes with a characteristic tun shape. Tun formation is an essential morphological adaptation for tardigrade entry into the anhydrobiotic state. The tun cell structure and ultrastructure have rarely been explored in tardigrades in general and never in Hypsibius exemplaris. We used transmission electron microscopy to compare cellular organization and ultrastructures between hydrated and anhydrobiotic H. exemplaris. Despite a globally similar cell organelle structure and a number of cells not significantly different between hydrated and desiccated tardigrades, reductions in the sizes of both cells and mitochondria were detected in dehydrated animals. Moreover, in anhydrobiotes, secretory active cells with a dense endoplasmic reticulum network were observed. Interestingly, these anhydrobiote-specific cells are in a close relationship with a specific extracellular structure surrounding each cell. It is possible that this rampart-like extracellular structure resulted from the accumulation of anhydrobiotic-specific material to protect the cells. Interestingly, after five hours of rehydration, the number of secretory cells decreased, and the specific extracellular structure began to disappear. Twenty-four hours after the beginning of rehydration, the cellular structure and ultrastructure were comparable to those observed in hydrated tardigrades.
| S-EPMC7062702 | biostudies-literature
Project description:Limno-terrestrial tardigrades enter a state called anhydrobiosis when exposed to desiccation, and acquire tolerance against various extreme environments. The anhydrobiotic tardigrade Hypsibius dujardini, is a non-pigmented tardigrade easy to culture and RNAi method have been established, therefore making it a model tardigrade for tardigrade molecular research. Previous genome assemblies of this tardigrade had increased size due to heterozygosity. Here, we have sequenced the genome of H. dujardini using single individual Illumina DNA-Seq data and PacBio long read data, and employed a heterozygosity aware assembly method to assemble a near-complete high quality genome. In order to annotate the genome with gene predictions, we conducted RNA-Sequencing of various stages of developmental, juvenile, adult, and anhydrobiotic stage H. dujardini and Ramazzottius varieornatus, a tardigrade capable of rapid anhydrobiosis entry, and used these data for gene prediction with BRAKER v1.9 or differential gene expression analysis of the active and anhydrobiotic stages.
2017-02-28 | GSE94295 | GEO
Project description:Tardigrades contain characteristic free-floating body cavity cells that are also called storage cells. To investigate the cell-specific expression patterns of tardigrade-unique genes, the expression levels of dissected storage cells are compared to those of the whole body.
2023-01-04 | GSE212632 | GEO
Project description:Recent studies have shown that proteins unique to tardigrades are involved in the remarkable ability of these small animals to withstand desiccation and ionizing radiation (IR). For resistance to IR, only one tardigrade unique protein has been identified so far: Dsup, for DNA damage suppressor, found in R. varieornatus and H. exemplaris. Rv-Dsup protects from DNA damage by X-rays in human cells, suggesting that DNA protection is important for resistance to IR. Here, we chose to investigate the role of DNA repair and search for novel tardigrade unique genes involved in resistance to IR. For this, we performed an unbiased proteome analysis of H. exemplaris either untreated, or at 4h post-irradiation, 24h post-irradiation and after Bleomycin treatment.
2024-06-17 | PXD043897 | Pride
Project description:The tardigrade Hypsibius exemplaris can undergo anhydrobiosis. Several chemicals that inhibit successful anhydrobiosis in H. exemplaris have been identified, and these chemicals inhibit the activity of signaling molecules. In the present study, we investigated whether upregulation of the activity of these signaling molecules could improve desiccation tolerance of H. exemplaris. Pre-treatment with an indirect activator of AMP-activated protein kinase [AMPK; which directly inhibits mammalian NAD(P)H dehydrogenase [quinone] 1 [NQO1] of mitochondrial complex I (D942)] significantly improved desiccation tolerance of H. exemplaris, whereas a direct activator of AMPK did not. To elucidate the underlying molecular mechanisms, we examined the proteome of tardigrades treated with D942. Two proteins, putative glutathione S-transferase and pirin-like protein, were upregulated by treatment. Both of these proteins are known to be associated with the response to oxidative stress. One of the downregulated proteins was serine/threonine-proteinphosphatase 2A (PP2A) 65-kDa regulatory subunit A alpha isoform, and it is interesting to note that PP2A activity was previously suggested to be required for successful anhydrobiosis in H. exemplaris. Taken together, our results suggest that D942 treatment may partially induce responses common to those of desiccation stress. The identification of a chemical that improves desiccation tolerance of H. exemplaris may facilitate further investigation into desiccation tolerance mechanisms.
| S-EPMC7459401 | biostudies-literature
Project description:Mitochondrial alternative oxidase (AOX) is predicted to be present in mitochondria of several invertebrate taxa including tardigrades. Independently of the reason concerning the enzyme occurrence in animal mitochondria, expression of AOX in human mitochondria is regarded as a potential therapeutic strategy. Till now, relevant data were obtained due to heterologous AOX expression in cells and animals without natively expressed AOX. Application of animals natively expressing AOX could importantly contribute to the research. Thus, we decided to investigate AOX activity in intact specimens of the tardigrade Hypsibius exemplaris. We observed that H. exemplaris specimens' tolerance to the blockage of the mitochondrial respiratory chain (MRC) cytochrome pathway was diminished in the presence of AOX inhibitor and the inhibitor-sensitive respiration enabled the tardigrade respiration under condition of the blockage. Importantly, these observations correlated with relevant changes of the mitochondrial inner membrane potential (Δψ) detected in intact animals. Moreover, detection of AOX at protein level required the MRC cytochrome pathway blockage. Overall, we demonstrated that AOX activity in tardigrades can be monitored by the animals' behavior observation as well as by measurement of intact specimens' whole-body respiration and Δψ. Furthermore, it is also possible to check the impact of the MRC cytochrome pathway blockage on AOX level as well as AOX inhibition in the absence of the blockage on animal functioning. Thus, H. exemplaris could be consider as a whole-animal model suitable to study AOX.
| S-EPMC8382173 | biostudies-literature
Project description:BackgroundBoth euarthropods and vertebrates have tripartite brains. Several orthologous genes are expressed in similar regionalized patterns during brain development in both vertebrates and euarthropods. These similarities have been used to support direct homology of the tripartite brains of vertebrates and euarthropods. If the tripartite brains of vertebrates and euarthropods are homologous, then one would expect other taxa to share this structure. More generally, examination of other taxa can help in tracing the evolutionary history of brain structures. Tardigrades are an interesting lineage on which to test this hypothesis because they are closely related to euarthropods, and whether they have a tripartite brain or unipartite brain has recently been a focus of debate.ResultsWe tested this hypothesis by analyzing the expression patterns of six3, orthodenticle, pax6, unplugged, and pax2/5/8 during brain development in the tardigrade Hypsibius exemplaris-formerly misidentified as Hypsibius dujardini. These genes were expressed in a staggered anteroposterior order in H. exemplaris, similar to what has been reported for mice and flies. However, only six3, orthodenticle, and pax6 were expressed in the developing brain. Unplugged was expressed broadly throughout the trunk and posterior head, before the appearance of the nervous system. Pax2/5/8 was expressed in the developing central and peripheral nervous system in the trunk.ConclusionOur results buttress the conclusion of our previous study of Hox genes-that the brain of tardigrades is only homologous to the protocerebrum of euarthropods. They support a model based on fossil evidence that the last common ancestor of tardigrades and euarthropods possessed a unipartite brain. Our results are inconsistent with the hypothesis that the tripartite brain of euarthropods is directly homologous to the tripartite brain of vertebrates.
| S-EPMC6065069 | biostudies-literature
Project description:Comparative transcriptomics in an anhydrobiotic tardigrade, Hypsibius dujardini, during desiccation treatment
| PRJDB5599 | ENA