Machinery and Developmental Role of Retinoic Acid Signaling in Echinoderms

Abstract

Although a recent genomic survey revealed its ancient evolutionary origin in the animal kingdom, retinoic acid (RA) signaling was previously thought to be unique to chordates. Echinoderms are of critical interest in researching the evolutionary history of RA signaling, as they represent a basal group of deuterostomes. Furthermore, our previous works have suggested that echinoderms may possess the ancestral function of RA signaling for metamorphosis regulation. In this paper, to facilitate future studies of RA signaling in echinoderms, we provide an overview of RA machinery in echinoderms, identify its signaling components, and discuss its developmental role.

Proceedings of the 68th Congress of the Italian Embryological Group-Italian Society of Development and Cell Biology (GEI-SIBSC) - Oliveri, 5-8 June 2023

“…Only a few research explored RA functions in echinoderm development: although RA genetic toolkit is present in the genome of several model species, RA exposure induced only minor effects during sea urchin embryogenesis while metamorphosis was strongly affected by the treatment in asteroids and crinoids. 6,7,8 We started to explore the role of RA in crinoid embryogenesis by exposing embryos of the Mediterranean feather star Antedon mediterranea to different concentrations of RA. Preliminary results suggested that RA affects larvae morphology and prevents the onset of metamorphosis.…”

Retinoic Acid and Retinoid X Receptors

“…The article discusses the requirement of RA for optic cup formation and morphogenesis of anterior eye structures and highlights the need for studies focusing on the identification of direct RA signaling targets during eye development. Yamakawa and Wada [ 25 ] use a comparative approach to review our current understanding of RA signaling in echinoderms, an important group of animals for studying the evolutionary diversification of RXR-RAR-dependent signaling. In addition to annotating RA signaling components in different echinoderms, they discuss possible roles for RA during echinoderm development and speculate on ancestral functions of this signaling system in echinoderms and beyond.…”