Essential developmental role during embryogenesis, in particular the normal development of the nervous system. May be involved in some aspect of cell adhesion. Detected in several sites including the ventral neuroectoderm, the tracheal pits, the pharynx and esophagus, and specific neuronal cell bodies, where it is primarily expressed. First expressed at the cellular blastoderm stage and continues to be expressed through subsequent development. By 20-hydroxyecdysone.