Demonstration of the Coexistence of Duplicated LH Receptors in Teleosts, and Their Origin in Ancestral Actinopterygians

• Published in: PLOS ONE
• Main Authors: Maugars, Gersende, Dufour, Sylvie
• Other Authors: Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems; Gar’; European eel
• Online Access: https://hal.sorbonne-universite.fr/hal-01236229; https://hal.sorbonne-universite.fr/hal-01236229/document; https://hal.sorbonne-universite.fr/hal-01236229/file/journal.pone.0135184.pdf; https://doi.org/10.1371/journal.pone.0135184

International audience Pituitary gonadotropins, FSH and LH, control gonad activity in vertebrates, via binding to their respective receptors, FSHR and LHR, members of GPCR superfamily. Until recently, it was accepted that gnathostomes possess a single FSHR and a single LHR, encoded by fshr and lhcgr genes. We reinvestigated this question, focusing on vertebrate species of key-phylogenetical positions. Genome analyses supported the presence of a single fshr and a single lhcgr in chondrichthyans, and in sarcopterygians including mammals, birds, amphibians and coelacanth. In contrast, we identified a single fshr but two lhgcr in basal tel-eosts, the eels. We further showed the coexistence of duplicated lhgcr in other actinoptery-gians, including a non-teleost, the gar, and other teleosts, e.g. Mexican tetra, platyfish, or tilapia. Phylogeny and synteny analyses supported the existence in actinopterygians of two lhgcr paralogs (lhgcr1/ lhgcr2), which do not result from the teleost-specific whole-genome duplication (3R), but likely from a local gene duplication that occurred early in the actinopter-ygian lineage. Due to gene losses, there was no impact of 3R on the number of gonadotro-pin receptors in extant teleosts. Additional gene losses during teleost radiation, led to a single lhgcr (lhgcr1 or lhgcr2) in some species, e.g. medaka and zebrafish. Sequence comparison highlighted divergences in the extracellular and intracellular domains of the duplicated lhgcr, suggesting differential properties such as ligand binding and activation mechanisms. Comparison of tissue distribution in the European eel, revealed that fshr and both lhgcr transcripts are expressed in the ovary and testis, but are differentially expressed in non-gonadal tissues such as brain or eye. Differences in structure-activity relationships and tissue expression may have contributed as selective drives in the conservation of the duplicated lhgcr. This study revises the evolutionary scenario and nomenclature of gonado-tropin receptors, and opens new ...