A C-ERB-A BINDING-SITE IN RAT GROWTH-HORMONE GENE MEDIATES TRANSACTIVATION BY THYROID-HORMONE
A C-ERB-A BINDING-SITE IN RAT GROWTH-HORMONE GENE MEDIATES TRANSACTIVATION BY THYROID-HORMONE
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DOI：
10.1038/329738a0
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发表时间：
1987-10-22
期刊：
影响因子：
64.8
通讯作者：
ROSENFELD, MG
中科院分区：
文献类型：
--
作者：
GLASS, CK;FRANCO, R;ROSENFELD, MG
物质3,5,3-三碘甲状腺原氨酸（T3）刺激大鼠垂体肿瘤细胞中的生长激素基因转录1 - 4。这种刺激被认为是通过核t3受体结合到转录起始位点的调控元件5′- 5 - 8介导的。由于核t3受体丰度低，无法纯化它们，并且缺乏影响t3调控的明确的t3受体- dna结合位点，对甲状腺激素激活基因转录的机制的了解一直受到限制。最近，人类和禽类的c- erbb - agene产物已被证明与甲状腺激素具有高亲和力9,10，并且具有甲状腺激素受体的分子量和核结合特征。在本报告中，我们描述了一种亲和素-生物素复合物dna结合试验的发展，该试验可以检测大鼠垂体细胞t3受体与序列5‘ cagggacgtgaccgca3 ’的特异性高亲和力结合，该序列位于大鼠生长激素基因转录起始位点5'的164个碱基对。在转染的大鼠垂体GC2细胞中，含有该序列的寡核苷酸将t3调控转移到单纯疱疹病毒胸苷激酶启动子上，并特异性结合人胎盘c- erbb - agene的一个蛋白体外翻译产物。这些数据提供了支持证据，证明人c- erbb - agene产物介导t3的转录作用，并且GC2细胞核提取物含有修饰垂体t3受体与大鼠生长激素基因t3反应元件结合的其他因子。
The substance 3,5,3-triiodothyronine (T3) stimulates growth hormone gene transcription in rat pituitary tumour cells1–4. This stimulation is thought to be mediated by the binding of nuclear T3receptors to regulatory elements 5' to the transcriptional start site5–8. Understanding of the mechanism by which thyroid hormone activates gene transcription has been limited by failure to purify nuclear T3receptors because of their low abundance, and by the absence of defined T3receptor-DNA binding sites affecting T3regulation. Recently, human and avian c-erb-Agene products have been shown to bind thyroid hormone with high affinity9,10and to have a molecular weight and nuclear association characteristic of the thyroid hormone receptor. In the present report, we describe the development of an avidin–biotin complex DNA-binding assay which can detect specific, high-affinity binding of rat pituitary cell T3receptors to the sequence 5'CAGGGACGTGACCGCA3', located 164 base pairs 5' to the transcriptional start site of the rat growth hormone gene. An oligonucleotide containing this sequence transferred T3regulation to the herpes simplex virus thymidine kinase promoter in transfected rat pituitary GC2 cells, and specifically bound anin vitrotranslation product of the human placental c-erb-Agene. The data provide supporting evidence that the human c-erb-Agene product mediates the transcriptional effects of T3and also that GC2 cell nuclear extracts contain additional factors that modify the binding of pituitary T3receptors to the rat growth hormone gene T3response element.