Project description:Differential expression analysis of triple knockdown of TBP and TBP-related factors (TKD) in Xenopus laevis embryos at early developmental stage 10.5
Project description:During gastrulation and neurulation, the chordamesoderm and overlying neuroectoderm of vertebrate embryos converge under the control of a specific genetic programme to the dorsal midline, simultaneously extending along it. However, whether mechanical tensions resulting from these morphogenetic movements play a role in long-range feedback signalling that in turn regulates gene expression in the chordamesoderm and neuroectoderm is unclear. In the present work, by using a model of artificially stretched explants of Xenopus midgastrula embryos and full-transcriptome sequencing, we identified genes with altered expression in response to external mechanical stretching. Importantly, mechanically activated genes appeared to be expressed during normal development in the trunk, i.e., in the stretched region only. By contrast, genes inhibited by mechanical stretching were normally expressed in the anterior neuroectoderm, where mechanical stress is low. These results indicate that mechanical tensions may play a role of a long-range signalling factor that regulates patterning of the embryo, serving as a link coupling morphogenesis and cell differentiation.
Project description: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 foundational experiment of experimental embryology. Since then, embryonic twinning has been obtained experimentally in many animals by diverse methods. In a recent study, we developed bisection methods that generate identical twins reliably from Xenopus blastula embryos. In the present study we investigated the transcriptome of regenerating half-embryos after sagittal and dorsal-ventral (D-V) bisections. Individual embryos were operated at midblastula with an eyelash hair and cultured until early gastrula (stage 10.5) or late gastrula (Stage 12) and analyzed the transcriptome of each half-embryo by RNAseq. Because many genes are activated by wound healing, stringent analyses were used to identify genes upregulated in identical twins but not in either dorsal or ventral fragments. At early gastrula cell division-related genes such as histones were identified, whereas at late gastrula pluripotency genes (such as sox2) and germ layer determining genes (such as eomesodermin, ripply2 and activing receptor ACVRI) and a number of secretory pathway components (serpinH1, fucoleptin and sialyl transferase). These findings are consistent with a model in which cell division is required to heal damage, while maintaining pluripotency to permit formation of the organizer with a displacement of 900 from its original site. In addition, the extensive transcriptomic data presented here (30 RNA-seq libraries of individual whole or regenerating half-embryos) provides a useful resource for data mining gene expression during early vertebrate development.