Heyland Andreas, Price David A, Bodnarova-Buganova Michaela, Moroz Leonid L
The Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA.
J Exp Zool B Mol Dev Evol. 2006 Nov 15;306(6):551-66. doi: 10.1002/jez.b.21113.
In mammals, thyroid hormone (TH) signaling is essential for metabolic control, differentiation and homeostasis. These hormones are also involved in the regulation of metamorphosis in amphibians and lampreys and a role in basal chordates has been suggested. Increasing evidence supports TH-related function not only in basal chordates such as urochordates and cephalochordates but also in other invertebrate groups. However, the regulatory mechanisms underlying TH function including the mechanisms of endogenous synthesis of hormones in these groups are essentially unknown. Our data provide evidence for endogenous TH synthesis in the sea hare Aplysia californica and the sea urchin Lytechinus variegatus based on thin layer chromatography. Pharmacological experiments show that these hormones accelerate development to metamorphosis and specifically affect the formation of juvenile skeletal structures in the sea urchin. Furthermore, we identified two new peroxidase genes (LvTPO from L. variegatus and AcaTPO from A. californica) showing high sequence similarity with peroxidasin and thyroid peroxidases (the critical TH synthesis enzymes found in all vertebrates). Spatial and temporal expression patterns of these transcripts suggest a role of LvTPO and AcaTPO in a variety of processes such as development to metamorphosis and the regulation of the animal's energetics. We discuss our new findings in the context of evolution of TH synthesis and TH signaling in non-chordate animals.
在哺乳动物中，甲状腺激素（TH）信号传导对于代谢控制、分化和体内平衡至关重要。这些激素还参与两栖动物和七鳃鳗变态的调节，并且有人提出它们在基础脊索动物中也发挥作用。越来越多的证据支持TH相关功能不仅存在于尾索动物和头索动物等基础脊索动物中，也存在于其他无脊椎动物群体中。然而，TH功能的调控机制，包括这些群体中激素的内源性合成机制，基本上仍不为人所知。我们的数据基于薄层色谱法为海兔加州海兔和海胆多色紫球海胆中的内源性TH合成提供了证据。药理学实验表明，这些激素加速发育至变态，并特别影响海胆幼体骨骼结构的形成。此外，我们鉴定了两个新的过氧化物酶基因（来自多色紫球海胆的LvTPO和来自加州海兔的AcaTPO），它们与过氧化物酶和甲状腺过氧化物酶（在所有脊椎动物中发现的关键TH合成酶）具有高度的序列相似性。这些转录本的时空表达模式表明LvTPO和AcaTPO在多种过程中发挥作用，如发育至变态以及动物能量学的调节。我们在非脊索动物中TH合成和TH信号传导的进化背景下讨论我们的新发现。
