The role of retinoic acid signaling in starfish metamorphosis

BACKGROUND: Although retinoic acid (RA) signaling plays a crucial role in the body patterning of chordates, its function in non-chordate invertebrates, other than its mediation of environmental cues triggering metamorphosis in cnidarians, is largely unknown. We investigated the role of RA signaling in the metamorphosis of starfish (Echinodermata). RESULTS: We found that exogenous RA treatment induced metamorphosis in starfish larvae. In contrast, inhibitors of RA synthesis and RA receptors suppressed metamorphosis triggered by attachment to a substrate. Gene expressions of the RA signaling component were detected in competent larvae. CONCLUSIONS: This study provides insight into the ancestral function of RA signaling, which is conserved in the metamorphosis of cnidarians and starfish. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13227-018-0098-x) contains supplementary material, which is available to authorized users.