- CoRest1 regulates neurogenesis in a stage-dependent manner. [Journal Article]
- DDDev Dyn 2019 Jul 13
- CONCLUSIONS: Based on these findings, the central role of CoRest1 in neurogenesis is likely due to a Rest- independent role rather than as a Rest co-repressor. This article is protected by copyright. All rights reserved.
- Integration of Wnt and FGF signaling in the Xenopus gastrula at TCF and Ets binding sites shows the importance of short range repression in patterning the marginal zone. [Journal Article]
- DDevelopment 2019 Jul 08
- During Xenopus gastrulation, Wnt and FGF signaling pathways cooperate to induce posterior structures. Wnt target expression around the blastopore falls into two main categories: a horseshoe shape wit…
During Xenopus gastrulation, Wnt and FGF signaling pathways cooperate to induce posterior structures. Wnt target expression around the blastopore falls into two main categories: a horseshoe shape with a dorsal gap, like Wnt8 expression, or a ring, like FGF8 expression. Using ChIPseq, we show, surprisingly, that FGF signaling mediator, Ets2, binds near all Wnt target genes. However, β-catenin preferentially binds at the promoters of genes with horseshoe patterns, but further from the promoter of genes with ring patterns. Manipulation of FGF or Wnt signaling demonstrated that "ring" genes are responsive to FGF signaling at the dorsal midline while "horseshoe" genes are predominantly regulated by Wnt signaling. We suggest that in the absence of active β-catenin at the dorsal midline the DNA binding protein TCF binds and actively represses gene activity only when close to the promoter. In contrast, genes without functional TCF sites at the promoter may be predominantly regulated by Ets at the dorsal midline and are expressed in a ring. These results suggest recruitment of only short-range repressors to potential Wnt targets in the Xenopus gastrula.
- Transcriptome analysis of regeneration during Xenopus laevis experimental twinning. [Journal Article]
- IJInt J Dev Biol 2019; 63(6-7):301-309
- Animal embryos have the remarkable property of self-organization. Over 125 years ago, Hans Driesch separated the two blastomeres of sea urchin embryos and obtained twins, in what was the foundation o…
Animal embryos have the remarkable property of self-organization. Over 125 years ago, Hans Driesch separated the two blastomeres of sea urchin embryos and obtained twins, in what was the foundation of experimental embryology. Since then, embryonic twinning has been obtained experimentally in many animals. In a recent study, we developed bisection methods that generate identical twins reliably from Xenopus blastula embryos. In the present study, we have investigated the transcriptome of regenerating half-embryos after sagittal and dorsal-ventral (D-V) bisections. Individual embryos were operated at midblastula (stage 8) with an eyelash hair and cultured until early gastrula (stage 10.5) or late gastrula (stage 12) and the transcriptome of both halves were analyzed by RNA-seq. Since many genes are activated by wound healing in Xenopus embryos, we resorted to stringent sequence analyses and identified genes up-regulated in identical twins but not in either dorsal or ventral fragments. At early gastrula, cell division-related transcripts such as histones were elevated, whereas at late gastrula, pluripotency genes (such as sox2) and germ layer determination genes (such as eomesodermin, ripply2 and activin receptor ACVRI) were identified. Among the down-regulated transcripts, sizzled, a regulator of Chordin stability, was prominent. These findings are consistent with a model in which cell division is required to heal damage, while maintaining pluripotency to allow formation of the organizer with a displacement of 90 0 from its original site. The extensive transcriptomic data presented here provides a valuable resource for data mining of gene expression during early vertebrate development.
- Transcriptional profiles of early stage red sea urchins (Mesocentrotus franciscanus) reveal differential regulation of gene expression across development. [Journal Article]
- MGMar Genomics 2019 Jun 18
- The red sea urchin, Mesocentrotus franciscanus, is an ecologically important kelp forest species that also serves as a valuable fisheries resource. In this study, we have assembled and annotated a de…
The red sea urchin, Mesocentrotus franciscanus, is an ecologically important kelp forest species that also serves as a valuable fisheries resource. In this study, we have assembled and annotated a developmental transcriptome for M. franciscanus that represents eggs and six stages of early development (8- to 16-cell, morula, hatched blastula, early gastrula, prism and early pluteus). Characterization of the transcriptome revealed distinct patterns of gene expression that corresponded to major developmental and morphological processes. In addition, the period during which maternally-controlled transcription was terminated and the zygotic genome was activated, the maternal-to-zygotic transition (MZT), was found to begin during early cleavage and persist through the hatched blastula stage, an observation that is similar to the timing of the MZT in other sea urchin species. The presented developmental transcriptome will serve as a useful resource for investigating, in both an ecological and fisheries context, how the early developmental stages of this species respond to environmental stressors.
- DEK terminates diapause by activation of quiescent cells in the crustacean Artemia. [Journal Article]
- BJBiochem J 2019 Jun 26; 476(12):1753-1769
- To cope with harsh environments, the Artemia shrimp produces gastrula embryos in diapause, a state of obligate dormancy, having cellular quiescence and suppressed metabolism. The mechanism behind the…
To cope with harsh environments, the Artemia shrimp produces gastrula embryos in diapause, a state of obligate dormancy, having cellular quiescence and suppressed metabolism. The mechanism behind these cellular events remains largely unknown. Here, we study the regulation of cell quiescence using diapause embryos of Artemia We found that Artemia DEK (Ar-DEK), a nuclear factor protein, was down-regulated in the quiescent cells of diapause embryos and enriched in the activated cells of post-diapause embryos. Knockdown of Ar-DEK induced the production of diapause embryos whereas the control Artemia released free-swimming nuaplii. Our results indicate that Ar-DEK correlated with the termination of cellular quiescence via the increase in euchromatin and decrease in heterochromatin. The phenomena of quiescence have many implications beyond shrimp ecology. In cancer cells, for example, knockdown of DEK also induced a short period of cellular quiescence and increased resistance to environmental stress in MCF-7 and MKN45 cancer cell lines. Analysis of RNA sequences in Artemia and in MCF-7 revealed that the Wnt and AURKA signaling pathways were all down-regulated and the p53 signaling pathway was up-regulated upon inhibition of DEK expression. Our results provide insight into the functions of Ar-DEK in the activation of cellular quiescence during diapause formation in Artemia.
- First molecular evidence of the toxicogenetic effects of copper on sea urchin Paracentrotus lividus embryo development. [Journal Article]
- WRWater Res 2019 Sep 01; 160:415-423
- Bioassays with sea urchin embryos are widely used to define the environmental quality of marine waters. Anomalies during embryogenesis are generally considered as end-points, whereas a toxigenomic ap…
Bioassays with sea urchin embryos are widely used to define the environmental quality of marine waters. Anomalies during embryogenesis are generally considered as end-points, whereas a toxigenomic approach, despite it is wide use in other species, is yet in its infancy. In the present study we evaluated toxigenic effects induced by copper on the sea urchin Paracentrotus lividus embryo, combining morphological observations with gene expression analysis. Many anthropogenic activities release copper in the marine environment, with harmful effects on aquatic organisms. In the present study P. lidivus embryos were exposed to different concentrations of copper (24, 36, 48 μg/L) and the activation of fifty specific marker genes, involved in different biological processes (stress, skeletogenesis, development/differentiation, detoxification) was investigated at early blastula, late gastrula and pluteus stage. At blastula stage no morphological anomalies were found, with early down-regulation of genes involved in development/differentiation and a moderate up-regulation of some detoxification genes. At gastrula stage a slight increase in developmental anomalies (up to 19% of malformed embryos) was followed by an increased number of targeted genes belonging to the same two classes, relative to the blastula stage. At pluteus stage morphological anomalies increased in a dose dependent manner. All the analyzed genes were strongly up-regulated, stress and skeletogenic genes showing a "late response" and almost all genes were targeted by copper at all the concentrations tested. The present study represents the first molecular report on the potential negative effect of copper on P. lividus embryos in the environment. Gene expression analysis should be considered as a promising tool for future environmental biomonitoring programs.
- Genotyping of Sea Anemone during Early Development. [Journal Article]
- JVJ Vis Exp 2019 May 13; (147)
- Described here is a PCR-based protocol to genotype the gastrula stage embryo of the anthozoan cnidarian Nematostella vectensis without sacrificing the life of the animal. Following in vitro fertiliza…
Described here is a PCR-based protocol to genotype the gastrula stage embryo of the anthozoan cnidarian Nematostella vectensis without sacrificing the life of the animal. Following in vitro fertilization and de-jellying, zygotes are allowed to develop for 24 h at room temperature to reach the early- to mid-gastrula stage. The gastrula embryos are then placed on an agarose gel bed in a Petri dish containing seawater. Under the dissecting microscope, a tungsten needle is used to surgically separate an aboral tissue fragment from each embryo. Post-surgery embryos are then allowed to heal and continue development. Genomic DNA is extracted from the isolated tissue fragment and used as a template for locus-specific PCR. The genotype can be determined based on the size of PCR products or presence/absence of allele-specific PCR products. Post-surgery embryos are then sorted according to the genotype. The duration of the entire genotyping process depends on the number of embryos to be screened, but it minimally requires 4-5 h. This method can be used to identify knockout mutants from a genetically heterogeneous population of embryos and enables analyses of phenotypes during development.
- A deficiency in SUMOylation activity disrupts multiple pathways leading to neural tube and heart defects in Xenopus embryos. [Journal Article]
- BGBMC Genomics 2019 May 17; 20(1):386
- CONCLUSIONS: We have identified changes in gene expression that underlie the neural tube and heart phenotypes resulting from depressed SUMOylation activity. Notably, these developmental defects correspond to the two most frequently occurring congenital birth defects in humans, strongly suggesting that perturbation of SUMOylation, either globally or of a specific protein, may frequently be the origin of these pathologies.
- Toxicological effects of Ramalina aspera (lichen) on Biomphalaria glabrata snails and Schistosoma mansoni cercariae. [Journal Article]
- ATActa Trop 2019; 196:172-179
- In this study, the molluscicidal activities against Biomphalaria glabrata and cercaricidal activities against Schistosoma mansoni of the ether extract of Ramalina aspera were evaluated. Additionally,…
In this study, the molluscicidal activities against Biomphalaria glabrata and cercaricidal activities against Schistosoma mansoni of the ether extract of Ramalina aspera were evaluated. Additionally, toxicity parameters were evaluated at sublethal doses in terms of the influence of the extract on the fertility and fecundity of snails, as well as morphological alterations and quantification of their immunological cells. A test with Artemia salina was also carried out, in order to verify the environmental toxicity of the compound. The ether extract of R. aspera, in which divaricatic acid was identified as the major compound, demonstrated molluscicidal activity at low concentrations against both embryos (LC90 of 22.78, 24.23, 16.63 and 16.03 μg mL-1 for the gastrula, blastula, trochophore and veliger, respectively) and against adult snails (LC90 of 8.66 μg mL-1), after 24 h of exposure. At the sublethal doses, it was possible to observe a decrease in fecundity and quantitative and morphological changes in the defense cells of the exposed snails. In addition, the extract of R. aspera showed a cercaricidal effect on S. mansoni from the concentration of 5.0 μg mL-1, while showing low toxicity to Artemia salina. The ether extract of R. aspera demonstrated effective molluscicidal activity on embryos and adult snails of the species B. glabrata, cercariae of S. mansoni, and presenting low toxicity on Artemia salina. In this way, it could be considered a promising compound in the development of future molluscicidal and cercaricidal agents, thus helping to combat schistosomiasis.
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- Discovery of sex-related genes from embryonic development stage based on transcriptome analysis in Eriocheir sinensis. [Journal Article]
- GENEGene 2019 Aug 20; 710:1-8
- Investigation of sex determination system in Eriocheir sinensis is important because of sex-dimorphism in its growth traits. However, little information about the sex-related genes in embryonic devel…
Investigation of sex determination system in Eriocheir sinensis is important because of sex-dimorphism in its growth traits. However, little information about the sex-related genes in embryonic development stages were exposed. To obtain more information of sex determination in Chinese mitten crab, we performed the transcriptome analysis in embryonic development stage (fertilized egg stage, cleavage stage, blastula stage, gastrula stage and heartbeat stage) of Chinese mitten crab using nextgeneration sequencing technology. Thirty-one of 32,088 annotated unigenes were identified as sex-related genes including 16 genes involved in primary sex determination in model organisms and 8 genes of SOX family and 7 genes of DMRT gene family. Heatmap based on the RPKM value in five embryonic development stages indicated that these genes were clustered into two branches. Analysis of the differentially expressed 12 genes, including 3 genes of SOX family, 3 genes of DMRT gene family and 6 genes involved in primary sex determination in model organisms, showed significantly difference between the first three periods (fertilized egg stage-cleavage stage-blastula stage) and the last two periods (gastrula stage-heartbeat stage) and all 12 genes were up-regulated after blastula stage. In conclusion, we inferred that sex determination might be initiated after blastula stage in E. sinensis. Transcriptome analysis from embryonic development stage could provide a background information for further investigation in sex determination of Eriocheir sinensis.