<it>Troponin T </it>isoform expression is modulated during Atlantic Halibut metamorphosis

• Main Authors: Llewellyn Lynda, Nowell Mari A, Silva Nádia, Campinho Marco A, Sweeney Glen E, Power Deborah M
• Format: Article
• Language: English
• Published: BMC 2007-06-01
• Series: BMC Developmental Biology
• Online Access: http://www.biomedcentral.com/1471-213X/7/71

<p>Abstract</p> <p>Background</p> <p>Flatfish metamorphosis is a thyroid hormone (TH) driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in <it>Troponin T </it>(<it>TnT</it>), a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied.</p> <p>Results</p> <p>In the present study five cDNAs for halibut <it>TnT </it>genes were cloned; three were splice variants arising from a single <it>fast TnT </it>(<it>fTnT</it>) gene; a fourth encoded a novel teleost specific fTnT-like cDNA (<it>AfTnT</it>) expressed exclusively in slow muscle and the fifth encoded the teleost specific <it>sTnT2</it>. THs modified the expression of halibut <it>fTnT </it>isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, <it>AfTnT </it>and <it>sTnT2</it>, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of <it>TnT </it>genes and muscle fibre organization occurred in halibut musculature.</p> <p>Conclusion</p> <p>Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in <it>TnT </it>gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.</p>