Adler G K, Smas C M, Fiandaca M, Frim D M, Majzoub J A
Department of Medicine, Children's Hospital, Boston, MA 02115.
Mol Cell Endocrinol. 1990 Apr 17;70(2):165-74. doi: 10.1016/0303-7207(90)90156-3.
The factors controlling the expression of the hypothalamic neuropeptide, corticotropin releasing hormone (CRH), are poorly understood. We have used a mouse anterior pituitary cell line, AtT-20, permanently transfected with the human CRH gene as a model for studying the regulation of the CRH gene by cyclic AMP. Previously, we demonstrated that in this system the CRH gene is correctly expressed and appropriately negatively regulated by glucocorticoids. Treatment of five CRH-producing cell lines with an activator of adenylate cyclase (forskolin, 0.1-50 microM for 24 h) caused a dose-dependent and specific increase in the amount of CRH mRNA and radioimmunoassay-detectable CRH peptide secreted into the medium. Ribonuclease protection analysis revealed that the CRH gene was transcribed from multiple transcriptional initiation sites located over several hundred nucleotides. Forskolin treatment resulted in a specific increase in the CRH mRNA transcripts initiating from one of these many transcriptional start sites.
目前对控制下丘脑神经肽促肾上腺皮质激素释放激素（CRH）表达的因素了解甚少。我们使用了一种永久转染了人CRH基因的小鼠垂体前叶细胞系AtT-20作为模型，来研究环磷酸腺苷（cAMP）对CRH基因的调控。此前，我们证明在这个系统中，CRH基因能够正确表达，并且受到糖皮质激素的适当负调控。用腺苷酸环化酶激活剂（毛喉素，0.1 - 50微摩尔，处理24小时）处理五个产生CRH的细胞系，导致CRH mRNA的量以及分泌到培养基中的放射免疫法可检测的CRH肽呈剂量依赖性和特异性增加。核糖核酸酶保护分析表明，CRH基因是从位于数百个核苷酸上的多个转录起始位点转录而来。毛喉素处理导致从这些众多转录起始位点之一起始的CRH mRNA转录本特异性增加。
