Thyroid hormone receptor expression during metamorphosis of Atlantic halibut (Hippoglossus hippoglossus)

• Published in: Molecular and Cellular Endocrinology
• Main Authors: Galay-Burgos, M., Power, Deborah, Llewellyn, Lynda, Sweeney, Glen E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2007
• Subjects: Akureyri; Bergen; Norway; Iceland
• Online Access: http://hdl.handle.net/10400.1/5486; https://doi.org/10.1016/j.mce.2007.10.009

Flatfish such as the Atlantic halibut (Hippoglossus hippoglossus) undergo a dramatic metamorphosis that transforms the pelagic, symmetric larva into a benthic, cranially asymmetric juvenile. In common with amphibian metamorphosis, flatfish metamorphosis is under endocrine control with thyroid hormones being particularly important. In this report we confirm that tri-iodothyronine (T3) levels peak at metamorphic climax during halibut metamorphosis. Moreover we have isolated cDNA clones of TR and TR genes and confirmed the presence in halibut of two TR isoforms (representing the products of distinct genes) and two TR isoforms (generated from a single gene by alternative splicing). Real time PCR was used to assess expression of these genes during metamorphosis. TR shows the most dramatic expression profile, with a peak occurring during metamorphic climax. This work has been carried out within the project “Arrested development: The Molecular and Endocrine Basis of Flatfish Metamorphosis” (Q5RS-2002-01192) with financial support from the Commission of the European Communities. However, it does not necessarily reflect the Commission’s views and in no way anticipates its future policy in this area. We thank Heiddis Smáradóttir (Fiskeldi Eyjafjarðar, IS-600 Akureyri, Iceland) for collecting and providing the Atlantic halibut samples, and Karin Pittman and Øystein Sæle (both from the Department of Biology, University of Bergen, Norway) for analysing samples to determine developmental stage. We are also grateful to Marco Campinho for preparing the RNA used in the study.