Chin W W, Carr F E
Department of Medicine, Brigham and Women's Hospital, Boston, MA.
Horm Metab Res Suppl. 1987;17:82-6.
In order to determine the molecular mechanisms by which thyroid hormone and other factors regulate the biosynthesis of thyrotropin (TSH), we have isolated and characterized the gene encoding the beta-subunit of rat TSH. The transcriptional unit is 4.9 Kb in size and contains 3 exons and two introns of 3.9 and 0.4 Kb. The gene possesses two promoters and hence two associated transcriptional start sites. Several lines of evidence indicate that there is differential regulation of the two TSH beta transcripts by thyroid hormone. In particular, rat TSH beta mRNA-2, the transcript associated with the downstream promoter, is regulated 6- to 8-fold by thyroid hormone. Further studies involving in vitro mutagenesis and transfection of the TSH beta gene into pituitary cells will hopefully provide important information concerning structure-function relations of the regulatory regions of the gene and thyroid hormone action.
为了确定甲状腺激素和其他因素调节促甲状腺激素（TSH）生物合成的分子机制，我们分离并鉴定了编码大鼠TSHβ亚基的基因。转录单元大小为4.9kb，包含3个外显子和两个分别为3.9kb和0.4kb的内含子。该基因有两个启动子，因此有两个相关的转录起始位点。几条证据表明，甲状腺激素对两种TSHβ转录本存在差异调节。特别是，与下游启动子相关的转录本大鼠TSHβmRNA-2受甲状腺激素调节6至8倍。涉及体外诱变以及将TSHβ基因转染到垂体细胞中的进一步研究有望提供有关该基因调控区域的结构-功能关系以及甲状腺激素作用的重要信息。
