title: Retinoic acid signaling in development: tissue-specific functions and evolutionary origins.
abstract: Retinoic acid (RA) is a vitamin A-derived morphogen important for axial patterning and organ formation in developing vertebrates and invertebrate chordates (tunicates and cephalochordates). Recent analyses of genomic data have revealed that the molecular components of the RA signaling cascade are also present in other invertebrate groups, such as hemichordates and sea urchins. In this review, we reassess the evolutionary origins of the RA signaling pathway by examining the presence of key factors of this signaling cascade in different metazoan genomes and by comparing tissue-specific roles for RA during development of different animals. This discussion of genomic and developmental data suggests that RA signaling might have originated earlier in metazoan evolution than previously thought. On the basis of this hypothesis, we conclude by proposing a scenario for the evolution of RA functions during development, which highlights functional gains and lineage-specific losses during metazoan diversification.
authors.affiliation: Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242-INRA 1288-ENS-UCBL, IFR128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, Lyon, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Campo-Paysaa
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Marlétaz
authors.forename: Vincent
authors.initials: V
authors.lastname: Laudet
authors.forename: Michael
authors.initials: M
authors.lastname: Schubert
mesh_terms: D000818:Animals; D047108:Embryonic Development; D006801:Humans; D009928:Organ Specificity; D015398:Signal Transduction; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D014212:Tretinoin