An endogenous peptide is involved in internal control of metamorphosis in the marine invertebrate Cassiopea xamachana (Cnidaria: Scyphozoa).

In the metagenetic life-cycle of the scyphozoan Cassiopea xamachana metamorphosis of planula-larvae or larva-like buds to polyps is triggered by specific external cues which are transmitted inside the larva or bud where internal signals finally coordinate the initiation of metamorphosis. This study deals with an endogenous metamorphosis inducer present in planulae and buds of Cassiopea. The inductive cue is localized in the basal part of the buds and can be characterized as a peptide with an apparent molecular weight of about 7,000 Da. Further purification was performed via reversed phase HPLC on a C18 column. Additional inhibitor assays revealed that protein kinase C and PI3 kinase, two known elements of the metamorphosis-inducing signal transduction cascade in Cassiopea, may act downstream of the endogenous inducing peptide.