Project description:Purpose: Construction of 3D zebrafish spatial transcriptomics data for studying the establishment of AP axis. Methods: We performed serial bulk RNA-seq data of zebrafish embryo at three development points. Using the published spatial transcriptomics data as references, we implemented Palette to infer spatial gene expression from bulk RNA-seq data and constructed 3D embryonic spatial transcriptomics. The constructed 3D transcriptomics data was then projected on zebrafish embryo images with 3D coordinates, establishing a spatial gene expression atlas named Danio rerio Asymmetrical Maps (DreAM). Results: DreAM provides a powerful platform for visualizing gene expression patterns on zebrafish morphology and investigating spatial cell-cell interactions. Conclusions: Our work used DreAM to explore the establishment of anteroposterior (AP) axis, and identified multiple morphogen gradients that played essential roles in determining cell AP positions. Finally, we difined a hox score, and comprehensively demonstrated the spatial collinearity of Hox genes at single-cell resolution during development.
Project description:Methyl tert-butyl ether (MTBE) has been shown to target developing vasculature in piscine and mammalian model systems. In the zebrafish, MTBE induces vascular lesions throughout development. These lesions result from exposure to MTBE at an early stage in development (6-somites to Prim-5 stages). During this time period, transcript levels of vegfa, vegfc, and vegfr1 were significantly decreased in embryos exposed to 5 mM MTBE. We performed global gene analysis as an unbiased approach to discover possible modes of action of MTBE vascular toxicity. Embryos were exposed at 3 hours post fertilization (hpf) in triplicate to one of three concentrations of MTBE: 5mM (induces vascular lesions and significantly decreases vegfa), 0.625mM (NOAEL; no observed adverse effect level), and 0.00625mM (100-fold below NOAEL), or to embryo media (control). Samples were collected at 6-somites (~15hpf), 21-somites (~24 hpf), and Prim-5 (~30 hpf) stages of development. Embryos were meticulously staged at exposure and at the time of collection to maintain a homogeneous population. Our experimental design sought to explore the effect of three concentrations MTBE on three different stages of zebrafish embryonic development during the critical period established for the chemical. This time period also corresponds to an important time in the cardiovascular system develop of our model vertebrate.