Sea Urchin Embryo: Specification of Cell Fate

Specification of cell fate in sea urchin embryos involves initial asymmetric distribution of maternal molecules that establish vegetal and nonvegetal domains of transcription activity. Subsequently, fates of most blastomeres are regulated by cell–cell interactions involving signalling ligands and cell surface receptors. Keywords: maternal determinants; cell–cell interactions; fate specification; transcription factors; receptors