TY - JOUR
T1 - Amphioxus Postembryonic Development Reveals the Homology of Chordate Metamorphosis
AU - Paris, Mathilde
AU - Escriva, Hector
AU - Schubert, Michael
AU - Brunet, Frédéric
AU - Brtko, Julius
AU - Ciesielski, Fabrice
AU - Roecklin, Dominique
AU - Vivat-Hannah, Valérie
AU - Jamin, Emilien L.
AU - Cravedi, Jean Pierre
AU - Scanlan, Thomas S.
AU - Renaud, Jean Paul
AU - Holland, Nicholas D.
AU - Laudet, Vincent
N1 - Funding Information:
We thank John Lawrence for generously providing laboratory space at the University of South Florida. We would also like to thank Gérard Benoît, François Bonneton, Bastien Boussau, Barbara Demeineix, Frédéric Flamant, and two anonymous reviewers for reading the manuscript and for fruitful discussion, Anne Chabadel for help with the confocal microscope, Georges Delous for technical help with TH measurements of amphioxus extracts, and Maria Danihelova for technical assistance. This work was supported by the Centre National de la Recherche Scientifique, the Ecole Normale Supérieure de Lyon, the Association pour la Recherche sur le Cancer (ARC), and the Ministere de l'Education Nationale, de la Recherche et de la Technologie (MENRT), by CRESCENDO, a European Union Integrated Project of FP6, and also by grants of the Network of Excellence (NoE) Project EC, FOOD-CT-2004-506319 (CASCADE) and VEGA No. 2/0022/08.
PY - 2008/6/3
Y1 - 2008/6/3
N2 - Most studies in evolution are centered on how homologous genes, structures, and/or processes appeared and diverged. Although historical homology is well defined as a concept, in practice its establishment can be problematic, especially for some morphological traits or developmental processes. Metamorphosis in chordates is such an enigmatic character. Defined as a spectacular postembryonic larva-to-adult transition, it shows a wide morphological diversity between the different chordate lineages, suggesting that it might have appeared several times independently. In vertebrates, metamorphosis is triggered by binding of the thyroid hormones (THs) T4 and T3 to thyroid-hormone receptors (TRs). Here we show that a TH derivative, triiodothyroacetic acid (TRIAC), induces metamorphosis in the cephalochordate amphioxus. The amphioxus TR (amphiTR) mediates spontaneous and TRIAC-induced metamorphosis because it strongly binds to TRIAC, and a specific TR antagonist, NH3, inhibits both spontaneous and TRIAC-induced metamorphosis. Moreover, as in amphibians, amphiTR expression levels increase around metamorphosis and are enhanced by THs. Therefore, TH-regulated metamorphosis, mediated by TR, is an ancestral feature of all chordates. This conservation of a regulatory network supports the homology of metamorphosis in the chordate lineage.
AB - Most studies in evolution are centered on how homologous genes, structures, and/or processes appeared and diverged. Although historical homology is well defined as a concept, in practice its establishment can be problematic, especially for some morphological traits or developmental processes. Metamorphosis in chordates is such an enigmatic character. Defined as a spectacular postembryonic larva-to-adult transition, it shows a wide morphological diversity between the different chordate lineages, suggesting that it might have appeared several times independently. In vertebrates, metamorphosis is triggered by binding of the thyroid hormones (THs) T4 and T3 to thyroid-hormone receptors (TRs). Here we show that a TH derivative, triiodothyroacetic acid (TRIAC), induces metamorphosis in the cephalochordate amphioxus. The amphioxus TR (amphiTR) mediates spontaneous and TRIAC-induced metamorphosis because it strongly binds to TRIAC, and a specific TR antagonist, NH3, inhibits both spontaneous and TRIAC-induced metamorphosis. Moreover, as in amphibians, amphiTR expression levels increase around metamorphosis and are enhanced by THs. Therefore, TH-regulated metamorphosis, mediated by TR, is an ancestral feature of all chordates. This conservation of a regulatory network supports the homology of metamorphosis in the chordate lineage.
KW - DEVBIO
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U2 - 10.1016/j.cub.2008.04.078
DO - 10.1016/j.cub.2008.04.078
M3 - Article
C2 - 18514519
AN - SCOPUS:44549084177
SN - 0960-9822
VL - 18
SP - 825
EP - 830
JO - Current Biology
JF - Current Biology
IS - 11
ER -