Gene expression and neuron subtype distribution in chordate dorsal ectoderms and ciliary bands of ambulacrarian larvae
Schematic drawing of cell clusters that comprise germ layers, organs, and tissues of gastrulae and larvae
(A) Gastrula (left side view). (B) Anatomical distribution of each cluster in gastrulae. (C) An early larva, left side view. (D) Anatomical distribution of each cluster in early larvae. Cluster numbers are shown with corresponding germ layers, organs, and tissues. This figure shows that for examples cells of cluster 8 comprise apical plate and cells of cluster 9 comprise coelom, a mesodermal derivative.
Comparison of gene expression in stomodeum formation region between ambulacrarian and chordate larvae
(A) Expression profiles of development-relevant genes in the stomodeal (mouth opening) region. The stomodeum is formed by stomodeal ectoderm (orange), stomodeal endoderm (blue) and oral endoderm (green). Most of genes expressed in these regions are major component genes of vertebrate Spemann’s organizer. (B) (Left) Gene expression pattern of chordate dorsal structures (notochord + floor plate), and (right) that of starfish larval stomodeum, transverse section of dotted line of (A). This suggests the ambulacrarian stomodeum plays a role of vertebrate Spemann’s organizer.
UMAP plot for clustering of embryonic cells obtained by single-cell RNA-seq analyses
Based on shared expression profiles of transcription factor genes and cellular signaling molecule genes, constituent cells of starfish embryos and larvae can be categorized into 22 clusters, numbered 0 to 21. Each dot represents each cell.