ACTH INDUCTION OF CYTOCHROME P450 IN ADRENAL CELLS

ACTH的慢性作用在体内维持最佳的类固醇生成能力 肾上腺皮质，确保肾上腺类固醇激素的产生 (皮质醇、皮质酮和醛固酮)。这个过程是 CAMP介导对编码基因施加转录压力 肾上腺皮质类固醇羟化酶(P450)及相关蛋白。这 竞争性更新建议确定四个同源结构域蛋白如何 与牛CYP17主要cAMP反应序列(CRS1)的结合 (P450c17)相互作用和基础转录 机械设备。使用体外转录/翻译，EMSA，细胞 转染法、体外转录和诱变法、二聚法和 这些同源结构域蛋白中的反式激活结构域将被确定 以及与其相互作用的共激活剂和/或TAFs。 肾上腺素对肾上腺线粒体P450活性的支持作用 皮质和大多数其他组织。编码该2FE-2S蛋白的基因 也受ACTH(CAMP)和新蛋白的转录调控 与此CRS的绑定将以与CYP17相同的方式进行表征 CRS1结合蛋白。这将允许比较依赖于cAMP的 基因的转录调控主要表达在 类固醇生成细胞(CyP17)，其中一个同时在类固醇生成细胞和类固醇生成细胞中表达 非类固醇生成细胞。运动所需的信号通路 促肾上腺皮质激素对类固醇合成基因的转录压力是cAMP- 反应和抑制环己酰亚胺(CHX)。夏令营响应/ CHX敏感基因将被确定为了解这一点的一种手段 信号通路。拟议的研究将为第一次 时间在生化水平上多肽荷尔蒙是如何从前 垂体中类固醇生成酶的控制水平以及提供 详细了解这一过程所需的信号传递途径。 这些事件是类固醇激素生物合成所必需的。 导致生殖能力和代谢动态平衡。

The chronic action of ACTH maintains optimal steroidogenic capacity in the adrenal cortex, assuring production of adrenal steroid hormones (cortisol, corticosterone and aldosterone) on demand. This process is mediated by cAMP exerting transcriptional pressure on genes encoding adrenocortical steroid hydroxylases (P450s) and related proteins. This competitive renewal proposes to determine how four homeodomain proteins binding to the predominant cAMP response sequence (CRS1) of bovine CYP17 (P450c17) interact with one another and the basal transcription machinery. Using in vitro transcription/translation, EMSA, cell transfection, in vitro transcription and mutagenesis; dimerization and transactivation domains in these homeodomain proteins will be identified along with coactivators and/or TAFs with which they interact. Adrenodoxin supports activity of mitochondrial P450s in the adrenal cortex and most other tissues. The gene encoding this 2Fe-2S protein is also regulated transcriptionally by ACTH(cAMP) and the novel protein binding to this CRS will be characterized in the same manner as CYP17 CRS1 binding proteins. This will permit comparison of cAMP-dependent transcriptional regulation of a gene predominantly expressed in steroidogenic cells (CYP17) with one expressed in both steroidogenic and nonsteroidogenic cells. The signalling pathway required for exertion of transcriptional pressure by ACTH of steroidogenic genes is cAMP- responsive and inhibited by cycloheximide (CHX). The cAMP-responsive/ CHX-sensitive locus will be identified as a means of understanding this signalling pathway. The proposed studies will establish for the first time at the biochemical level how peptide hormones from the anterior pituitary control levels of steroidogenic enzymes as well as providing detailed insight into the signalling pathway required for this process. These events are required for the biosynthesis of steroid hormones leading to reproductive capacity and metabolic homeostasis.