MOLECULAR BIOLOGY OF PITUITARY GLYCOPROTEIN AND HYPOTHALAMIC RELEASING HORMONES

人TSH β基因仅在人的促甲状腺细胞中表达， 垂体前叶，受下丘脑激素调节，周期性 AMP以及甲状腺激素。 最近的研究表明，TRH 和环腺苷酸介导其转录作用的大部分通过 特异性垂体因子pit-1磷酸化的变化， 与转录起始点的上游区域结合。 与此相反的是， 甲状腺激素通过与一种调节因子结合来介导其抑制作用， 第一个转录起始点下游的元件 未翻译外显子 我们最近已经详细地表征了TGGGTCA基序在-1/+6处的结构。 与上游pit-1一起介导的hTSH-β基因 hTSH-β基因位点、蛋白激酶C和A以及TRH刺激 表情 我们还表明，c-fos和c-jun与 该下游位点调节T3对hTSH-β基因表达的抑制。

The human TSH beta gene is expressed only in the thyrotrophs of the anterior pituitary where it is regulated by hypothalamic hormones, cyclic AMP as well as thyroid hormone. Recent studies have indicated that TRH and cyclic AMP mediate their transcriptional action in large part through changes in phosphorylation of the specific pituitary factor pit-1 which binds to a region upstream of the start of transcription. In contrast, thyroid hormone mediates its inhibition through binding to a regulatory element downstream of the start of transcription in the first untranslated exon. We have recently characterized in detail a TGGGTCA motif at -1/+6 of the hTSH-beta gene that mediates, in conjunction with the upstream pit-1 site, protein kinase C and A as well as TRH stimulation of hTSH-beta gene expression. We have also shown that c-fos and c-jun which interact with this downstream site modulate T3 inhibition of hTSH-beta gene expression.