Tissue-specific thyroid hormone regulation of gene transcripts encoding iodothyronine deiodinases and thyroid hormone receptors in striped parrotfish (Scarus iseri)
Tissue-specific thyroid hormone regulation of gene transcripts encoding iodothyronine deiodinases and thyroid hormone receptors in striped parrotfish (Scarus iseri)
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DOI：
10.1016/j.ygcen.2011.04.022
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发表时间：
2011-07-01
影响因子：
2.7
通讯作者：
Lema, Sean C.
中科院分区：
文献类型：
--
作者：
Johnson, Kaitlin M.;Lema, Sean C.
在鱼类和其他脊椎动物中，甲状腺激素的不同功能是通过碘甲状腺原氨酸脱碘酶(DIO)和甲状腺激素受体(TR)蛋白在外周组织水平上调节的。在这项研究中，我们研究了编码三种脱碘酶dio1、dio2和dio3-的mRNAs以及三种甲状腺激素受体trαA、trαB和trβ-在斑纹鹦鹉(Scarus Iseri)早期阶段对甲状腺激素的调节。用溶解相T-3(20 Nm)或他巴唑(3 MM)处理鹦鹉3d。外源性T-3治疗可升高循环T-3，而他巴唑治疗可降低血浆T-4水平。实验诱导的甲状腺功能亢进症增加了肝脏和大脑中编码trαA和trβ的转录本的相对丰度，但不影响这两个组织中trαB的mRNA水平。在两性中，用他巴唑处理的鱼在肝脏和大脑中表现出较高的dio2转录，这表明这些组织的外环去碘活性增强。因此，全身性甲状腺功能亢进症提高了这些组织中的相对dio3转录水平。然而，在性腺中，转录调控模式明显不同，T-3水平升高，在睾丸和卵巢组织中编码dio2的mRNAs增加，而在睾丸中编码dio3、trαA和trαB的mRNAs增加。甲状腺激素状况不影响肝脏、脑或性腺中Dio1转录的丰度。综上所述，这些结果表明，甲状腺状态影响肝脏中dio2和dio3的相对转录丰度，为大脑中类似的dio2和dio3基因调控模式提供了新的证据，并表明鱼类在甲状腺状态改变时表现出tr亚型特异性的转录丰度变化。(C)2011 Elsevier Inc.保留所有权利。
In fish as in other vertebrates, the diverse functions of thyroid hormones are mediated at the peripheral tissue level through iodothyronine deiodinase (dio) enzymes and thyroid hormone receptor (tr) proteins. In this study, we examined thyroid hormone regulation of mRNAs encoding the three deiodinases dio1, dio2 and dio3 - as well as three thyroid hormone receptors tr alpha A, tr alpha B and tr beta - in initial phase striped parrotfish (Scarus iseri). Parrotfish were treated with dissolved phase T-3 (20 nM) or methimazole (3 mM) for 3 days. Treatment with exogenous T-3 elevated circulating T-3, while the methimazole treatment depressed plasma T-4. Experimentally-induced hyperthyroidism increased the relative abundance of transcripts encoding tr alpha A and tr beta in the liver and brain, but did not affect tr alpha B mRNA levels in either tissue. In both sexes, methimazole-treated fish exhibited elevated dio2 transcripts in the liver and brain, suggesting enhanced outer-ring deiodination activity in these tissues. Accordingly, systemic hyperthyroidism elevated relative dio3 transcript levels in these same tissues. In the gonad, however, patterns of transcript regulation were distinctly different with elevated T-3 increasing mRNAs encoding dio2 in testicular and ovarian tissues and dio3, tr alpha A and tr alpha B in the testes only. Thyroid hormone status did not affect dio1 transcript abundance in the liver, brain or gonads. Taken as a whole, these results demonstrate that thyroidal status influences relative transcript abundance for dio2 and dio3 in the liver, provide new evidence for similar patterns of dio2 and dio3 mRNA regulation in the brain, and make evident that fish exhibit tr subtype-specific transcript abundance changes to altered thyroid status. (C) 2011 Elsevier Inc. All rights reserved.