Cloning of the cDNA for thyroid stimulating hormone β subunit and changes in activity of the pituitary-thyroid axis during silvering of the Japanese eel, Anguilla japonica
Cloning of the cDNA for thyroid stimulating hormone β subunit and changes in activity of the pituitary-thyroid axis during silvering of the Japanese eel, Anguilla japonica
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DOI：
10.1677/jme.0.0320179
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发表时间：
2004-02-01
影响因子：
3.5
通讯作者：
Yu, JYL
中科院分区：
文献类型：
--
作者：
Han, YS;Liao, IC;Yu, JYL
本研究的目的是：（1）克隆垂体促甲状腺激素β亚基的cDNA本研究的目的是通过克隆日本鳗鲡（Anguilla japonica）的促甲状腺激素β（TSH β）基因及其基因组DNA序列，进行系统发育分析，并研究促甲状腺激素β（TSH β）基因在培养的脑垂体中的表达调控;（2）研究野生雌鳗卵巢发育不同阶段的垂体TSH β mRNA转录水平和血清甲状腺素水平。根据皮肤颜色和卵母细胞直径将雌鳗的成熟分为幼鳗、亚成体、前银期和银期4个阶段。TSH β亚基的基因组DNA包含两个内含子和三个外显子，并且TSH β蛋白具有20个氨基酸的推定信号肽和127个氨基酸的成熟肽。日本鳗鲡TSH β成熟肽氨基酸序列与硬骨鱼类和其他脊椎动物的同源性分别为：欧洲鳗鲡（98.4%）、鲑科鱼类（60-6-61.3%）、鲤鱼（52.0-56.7%）、鲟鱼（48.4%）和四足动物（42.9-45.2%）。在TSH β mRNA调节的体外研究中发现，促甲状腺激素释放激素增加，而甲状腺素降低其表达。RT-PCR和实时荧光定量PCR分析结果表明，在银化过程中，TSH β亚基的转录水平升高。血清甲状腺素水平也增加与TSH β mRNA表达在镀银，支持下丘脑-垂体-甲状腺轴与镀银在野生雌性日本鳗鱼的假设。
The purposes of this study were: (1) to clone the cDNA encoding pituitary thyroid-stimulating hormone beta subunit (TSH beta) of the Japanese eel, Anguilla japonica, together with its genomic DNA sequence, for phylogenetic analysis, and to study the regulation of the TSH beta gene expression in cultured pituitaries; and (2) to investigate the transcript levels of pituitary TSH beta mRNA and the serum thyroxine profiles at different stages of ovarian development before and during silvering in the wild female eels. The maturity of female eels was divided into four stages, juvenile, sub-adult, pre-silver, and silver, based on skin color and oocyte diameter. The genomic DNA of the TSH beta subunit contains two introns and three exons, and the TSH beta protein possesses a putative signal peptide of 20 amino acids and a mature peptide of 127 amino acids. The amino acid sequence identities of TSH beta mature peptide of Japanese eel compared with those of teleosts and other vertebrates are: European eel (98.4%), salmonids (60-6-61.3%), carps (52.0-56.7%), sturgeon (48.4%), and tetrapods (42.9-45.2%). In in vitro studies of the regulation of TSH beta mRNA it was found that thyrotropin-releasing hormone increased while thyroxine decreased its expression. RT-PCR and real-time quantitative PCR analysis showed that the transcript levels of TSH beta subunit increased during eel silvering. The serum thyroxine levels also increased in parallel with TSH beta mRNA expression during silvering, supporting the hypothesis that the hypothalamus-pituitary-thyroid axis is correlated to silvering in the wild female Japanese eels.