Figure 8.
Illustration of skeletogenesis-related regions in starfish larvae (a) and comparison of gene regulatory network (GRN) models (b). (a) Our data suggest that adult skeletogenic cells are derived from cells included in the posterior coelom, and Vegf ligand emitted from the posterior ectoderm binds and activates the receptor Vegfr in dorsal mesenchyme cell lineage, which leads to the formation of adult skeletal rudiments on the dorsal left side of starfish larvae. (b) GRN models for adult skeletogenesis in starfish (left) or larval skeletogenesis in cidaroids (center) and euechinoids (right). The regulatory relationships shown by dotted lines were indicated by gene expression analyses. The cidaroid and euechinoid models are based on previous studies27,29,45,46.