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Analysis of thyroid hormone action in the cell ; Mechanism of induction and function of the hormone-responsive protein.

分析甲状腺激素在细胞中的作用；

基本信息

批准号：
03671141
负责人：
ICHIKAWA Kazuo
金额：
$ 1.34万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03671141/
关键词：
Thryoid hormone Peroxisome T3 responsive element cellular T3 transport Cell cycle Nuclear T3 receptor Cell proliferation dRLh-84 cell T3 responsive element 細胞内T_3輸送核T_3受容体糖尿病リンゴ酸酵素細胞核甲状腺ホルモン受容体細胞質T3結合蛋白質大腸菌発現ベクター Non

项目摘要

1) Thyroid hormone-responsive rat hepatic t protein turned out to be a peroxisomal bifunctional enzyme. The amount of t Protein and the t Protein mRNA were increased after thyroidectomy and were decreased within 24 hrs after administration of small amount of triiodothyronine(T3) (0.3-1.0 mug/100 g body weight). By means of CAT assay, it was shown that 5' flanking region of the t protein gene contained negative T3 responsive element, indicating that negative regulation of the t protein by thyroid hormone was exerted at the transcriptional level.2) We isolated cDNA fragment of rat hepatic nuclear n protein using antibody probe. It was shown that the induction of n protein by T3 was due to the increase of mRNA.However the idea that the cDNA fragment we isolated really encodes the n protein was not yet verified. For this purpose, we are planning to show that the amino acid sequences deduced from nucleotide sequences of the cDNA and those obtained from protein sequencing are the same.3) We showed that carrier mediated and energy dependent cellular uptake of T3 is important source of nuclear T3. We showed that the nuclear entry of T3 is not solely via passive diffusion and is somehow regulated in the cell. It was also shown that the cellular transport of T3 is different from that of thyroxine(T4). Unlike T4, T3 transport is altered as the cells go through cell cycle. T3 is most actively transported into the cell at S phase when number of nuclear T3 receptor was increased. Additionally, T3 exerted proliferative effect on dRLh-84 cells through shortening of the S phase, suggesting that T3 action is enhanced in S phase due to increased number of receptor and enhanced uptake of T3.

1) 甲状腺激素反应性大鼠肝 t 蛋白被证明是一种过氧化物酶体双功能酶。甲状腺切除术后t蛋白和t蛋白mRNA的量增加，给予少量三碘甲状腺原氨酸(T3)(0.3-1.0μg/100g体重)后24小时内减少。 CAT检测结果显示，t蛋白基因5'侧翼区含有负性T3效应元件，表明甲状腺激素对t蛋白的负调控作用是在转录水平上发挥的。2)用抗体探针分离了大鼠肝核n蛋白的cDNA片段。结果表明，T3诱导n蛋白是由于mRNA的增加。然而，我们分离的cDNA片段是否真正编码n蛋白的想法尚未得到证实。为此，我们计划证明从cDNA核苷酸序列推导的氨基酸序列与从蛋白质测序获得的氨基酸序列是相同的。3)我们表明载体介导和能量依赖性的T3细胞摄取是核T3的重要来源。我们发现 T3 的入核不仅仅通过被动扩散，而且在细胞中受到某种调节。还表明T3的细胞转运与甲状腺素(T4)不同。与 T4 不同，T3 转运随着细胞经历细胞周期而改变。当核 T3 受体数量增加时，T3 在 S 期最活跃地转运到细胞中。此外，T3通过缩短S期对dRLh-84细胞发挥增殖作用，表明由于受体数量增加和T3摄取增强，T3作用在S期增强。