Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1095558 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Frogs are an ecologically diverse and phylogenetically ancient group of anuran amphibians that include important vertebrate cell and developmental model systems, notably the genus Xenopus. Here we report a high-quality reference genome sequence for the western clawed frog, Xenopus tropicalis, along with draft chromosome-scale sequences of three distantly related emerging model frog species, Eleutherodactylus coqui, Engystomops pustulosus and Hymenochirus boettgeri. Frog chromosomes have remained remarkably stable since the Mesozoic Era, with limited Robertsonian (i.e., centric) translocations and end-to-end fusions found among the smaller chromosomes. Conservation of synteny includes conservation of centromere locations, marked by centromeric tandem repeats associated with Cenp-a binding, surrounded by pericentromeric LINE/L1 elements. We explored chromosome structure across frogs, using a dense meiotic linkage map for X. tropicalis and chromatin conformation capture (Hi-C) data for all species. Abundant satellite repeats occupy the unusually long (~20 megabase) terminal regions of each chromosome that coincide with high rates of recombination. Both embryonic and differentiated cells show reproducible association of centromeric chromatin, and of telomeres, reflecting a Rabl-like configuration. Our comparative analyses reveal 13 conserved ancestral anuran chromosomes from which contemporary frog genomes were constructed.
2022-03-30 | GSE199671 | GEO
Project description:An established population of African clawed frogs (Xenopus laevis) in mainland China
| PRJEB30999 | ENA
Project description:Amphibians such as the salamanders and the African clawed frog Xenopus are great models for regeneration studies because they can fully regenerate their lost organs. While axolotl can regenerate damaged organs throughout its lifetime, Xenopus has a limited regeneration capacity after metamorphosis. The ecotropic viral integrative factor 5 (Evi5), a cell-cycle-regulated protein that prevents cells from entering mitosis prematurely, is of great interest for it is highly upregulated in the limb blastema of axolotls, but its expression level remains unchanged in the fibroblastema of postmetamorphic frogs. Yet, its role in regeneration competent context in Xenopus has not been fully analyzed. Here we show that Evi5 is also upregulated in Xenopus tadpoles after limb and tail amputation, as it is in axolotls. Down-regulation of Evi5 with morpholino antisense oligos (Mo) impairs wound healing and blastema formation in limbs and tails in both axolotls and Xenopus tadpoles, suggesting a conserved function for Evi5 in regeneration. Using skin punch as a healing model we show that Evi5 is also involved in cell migration during wound healing. RNA-sequencing analysis shows that in addition to reduced signaling of Lepr, Pdgfa, Gdf5, evi5 Mo also downregulate lysine demethylases kdm6b and kdm7a, which are also required for limb regeneration. Thus, our results demonstrate that Evi5 plays a critical role in the regeneration of multiple systems in amphibians.
2022-11-24 | GSE218034 | GEO
Project description:Congo dwarf clawed frog is related to clawed frogs of the genus Xenopus
| PRJNA68371 | ENA
Project description:Merlin's clawed frog is distantly related to clawed frogs in the genus Xenopus
| PRJNA68375 | ENA
Project description:Hybridization of eggs and sperm from closely related species can give rise to genetic diversity, or can lead to embryo inviability due to incompatibility. Although central to evolution, the cellular and molecular mechanisms underlying postzygotic barriers that drive reproductive isolation and speciation remain largely unknown. Species of the African Clawed frog Xenopus provide an ideal system to study hybridization and genome evolution. Xenopus laevis is an allotetraploid with 36 chromosomes that arose through interspecific hybridization of diploid progenitors, whereas Xenopus tropicalis is a diploid with 20 chromosomes that diverged from a common ancestor ~48 million years ago. Differences in genome size between the two species are accompanied by organism size differences, and size scaling of the egg and subcellular structures such as nuclei and spindles formed in egg extracts. Nevertheless, early development transcriptional programs, gene expression patterns, and protein sequences are generally conserved. Interestingly, whereas the hybrid produced when X. laevis eggs are fertilized by X. tropicalis sperm (le×ts) is viable, the reverse hybrid (te×ls) dies prior to gastrulation. Here, we applied cell biological tools and high-throughput methods to study the mechanisms underlying hybrid inviability. We reveal that two specific X. laevis chromosomes are incompatible with the X. tropicalis cytoplasm and are mis-segregated during mitosis, leading to unbalanced gene expression at the maternal to zygotic transition, followed by cell-autonomous catastrophic embryo death.
2017-11-01 | GSE106157 | GEO
Project description:The aim of the study was to determine the protein composition of cornified claws of the western clawed frog (Xenopus tropicalis) in comparison to clawless toe tips and back skin. Cornified claws develop on toes I, II, III of the hind limbs, which we refer to as hind limb inner (HI) toes. Toes IV, V of the hind limbs, here referred to as hind limb outer (HO) toes lack claws. Proteins were prepared from HI toe tips including claws, HO toe tips and back skin (BSK) of frogs each (F1, F2, F3) and subjected to proteomic analysis.
2024-02-20 | PXD041765 | Pride
Project description:In this work, we developed a microprobe capillary electrophoresis high-resolution mass spectrometry approach to identify proteins in single identified cells in live embryos of the South African clawed frog (Xenopus laevis) and also zebrafish. We used a pulled borosilicate capillary to aspirate a calibrated portion of the cell of interest. Proteins in the collected aspirate were detected and quantified via a bottom-up proteomic workflow that was downscaled to the single cells. The microprobe mass spectrometry platform is scalable to smaller cells in live, morphologically complex, developing embryos. As an example, we used this approach to analyze proteomic changes in cells that form a clone in the early developing Xenopus laevis embryo.
2020-05-26 | PXD006905 | Pride
Project description:Pregnane X receptor (PXR) is generally considered the most important sensor of natural and anthropogenic xenobiotics in vertebrates. In Xenopus, however, PXR plays a role in neural development and it is irresponsive to xenobiotics. We report a first broad-spectrum amphibian xenobiotic receptor, which is an ortholog of the mammalian constitutive androstane receptor (CAR). The low basal activity and pronounced responsiveness to activators such as drugs and steroids displayed by the Xenopus CAR resemble PXR, which both trace back to a common ancestor early in the divergence of land vertebrates. The constitutive activity of CAR emerged first in Sauropsida (reptiles and birds) and it is common to all fully terrestrial land vertebrates (Amniota). This activity can be mimicked by humanizing just two amino acids of the Xenopus CAR. These results demonstrate a remarkable plasticity of CAR which enabled its employment as Xenopus xenosensors. They open way to toxicogenomic and bioaugmentation studies in amphibians, a critically endangered taxon of land vertebrates. Taken together, we provide evidence for a much earlier origin of CAR, for its conservation in tetrapods which exceeds that of PXR, and for its remarkable functional plasticity which enabled its role as a PXR-like xenosensor in Amphibia. We used microarrays to detect global transcriptional changes in Xenopus laevis livers following pregnenolone and artemisinin treatment in order to identify target genes of xlCAR. Arteminisin or pregnenolone were injected intraperitoneally into three frogs on two consecutive days. The control group received in parallel two DMSO injections. All frogs were sacrificed 24 h after the second injection by decapitation, and livers were immediately frozen in liquid nitrogen. After RNA isolation, specimens within the same experimental group were pooled.
2011-10-10 | E-GEOD-28510 | biostudies-arrayexpress
Project description:Leptin binding to the leptin receptor (LepR) causes rapid signaling to the nucleus. We investigated the early (2 hr) transcriptional response to acute leptin injectio (intracerebroventricular) in the preoptic area/hypothalamus/pituitary of juvenile Xenopus laevis frogs. Frogs were given i.c.v. injections of 0.6% saline or recombinant X. laevis leptin (rxLeptin; 20 ng/g BW) and 2 hrs later killed and the preoptic area/hypothalamus/pituitary dissected.
2014-08-05 | E-GEOD-60053 | biostudies-arrayexpress