StAR expression: Integration of Transcription with regulation via the mRNA 3'UTR

StAR 表达：通过 mRNA 3UTR 进行转录与调控的整合

• 批准号: 7661675
• 负责人: COLIN ROBERT JEFCOATE
• 金额: $ 31.29万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-22 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7661675
• 关键词: 3' Untranslated Regions; Acetylation; Acetylesterase; Acute; Address; Adrenal Cortex; Adrenal Glands; Adrenal gland hypofunction; Affect; Attenuated; Binding; CREB1 gene; Cardiovascular system; Cattle; Cell Line; Cell Separation; Cells; Characteristics; Cholesterol; Cholesterol Monooxygenase (Side-Chain-Cleaving); Complex; Corticotropin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dependence; Excision; Fingers; Genes; Genetic Transcription; Genetic Translation; Histone Acetylation; Histones; Human; Hydrocortisone; Laboratories; Lead; Ligands; Lipids; Mediating; Mediation; Mediator of activation protein; Messenger RNA; Metabolic syndrome; Modification; Mus; Mutate; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Nuclear Export; Output; Pathway interactions; Phorbol Esters; Phosphorylation; Phosphotransferases; Play; Post-Transcriptional Regulation; Post-Translational Protein Processing; Pregnenolone; Process; Protein Kinase C; Proteins; RNA Polymerase II; Reaction Time; Regulation; Research; Role; SF1; Site; Specific qualifier value; Staging; Steroid biosynthesis; Steroids; Stimulus; Stress; Testing; Testis; Time; Tissues; Transcript; Transcriptional Activation; Transgenes; Translations; Trichostatin A; U-0126; Work; base; biological adaptation to stress; butyrate response factor 1; chromatin immunoprecipitation; citrate carrier; dietary control; genetic regulatory protein; hypothalamic-pituitary-adrenal axis; in vivo; inhibitor/antagonist; leptomycin B; mRNA Transcript Degradation; novel; promoter; response; transcription factor

DESCRIPTION (provided by applicant): Cortisol synthesis in the adrenal cortex plays a central role in stress responses, in dietary control, and in cardiovascular regulation. Aberrations in this control of the hypothalamic pituitary adrenal axis play an important part in the Metabolic Syndrome that is often associated with Type 2 diabetes. ACTH stimulation of cortisol synthesis starts with the conversion of cholesterol to pregnenolone by mitochondrial cytochrome P450 11A1. Activation of this step depends on new synthesis of the steroidogenesis acute regulator (StAR) and its phosphorylation by protein kinase A (PKA). StAR deficiency causes hyperlipidemic adrenal insufficiency. This research focuses on the finding that StAR expression is stimulated in very different ways by PKA and by protein kinase C (PKC). We will show how these processes are clearly distinguished by essential contributions from, respectively, histone de-acetylatases and Erk kinase. We will characterize these processes for different contributions from nuclear factors, including the differentiation regulator, SF-1. This includes time-dependent modifications that cycle up and down during transcription (phosphorylation/de-phosphorylation and acetylation/de- acetylation). Evidence will be developed that PKA can also enhance a late stage in the PKC process, thus producing strong synergy in StAR transcription. Post transcriptional regulation of StAR provides another point of distinction between PKA and PKC regulation. A novel regulator, the Zn finger protein, TIS11b, targets specific sequences in the extended 3'untranslated region of the 3.5 kb StAR mRNA. TIS11b is rapidly stimulated by PKA, but suppressed by PKC. We will identify specific TIS11b recognition sites at the end of the StAR 3.5 kb mRNA and show that this interaction can enhance StAR protein translation, while increasing mRNA degradation. We will test whether TIS11b is co-transcribed with StAR due to shared transcription factors, including SF-1. We will determine how these mechanisms interplay during ACTH stimulation, including in primary adrenal cell lines and in adrenals in vivo. The promoter and mRNA sequences that specify SF-1 and TIS11b interactions during StAR expression are substantially conserved from mouse to humans. We will test whether these mouse mechanisms are retained in human adrenal H295 cells. Our research shows that TIS11b interaction with StAR and predominance of an extended StAR mRNA are conserved in primary bovine adrenal cells and respond to ACTH. This work will bring together several laboratories to provide a first look at the interplay between PKA, SF-1, and TIS11b (or factors related to each), which is likely to occur in multiple steroidogenic tissues. Cortisol synthesis in the adrenal cortex plays a central role in stress responses, in dietary control, and in cardiovascular regulation. ACTH, which is elevated by stress, stimulates cortisol synthesis through enhanced conversion of cholesterol to pregnenolone. This step depends on new synthesis of the steroidogenesis acute regulator (StAR). The proposed research addresses a novel process, whereby ACTH stimulates not only transcription of StAR, but also a protein called TIS11b, which separately regulates StAR protein translation and mRNA degradation. We make a detailed analysis of regulatory processes that control StAR and TIS11b transcription in order to understand their potential coordination. TIS11b may accelerate the response time to stress, while also aiding in the removal of StAR when the ACTH stimulus is removed. TIS11b regulation is present in other tissues that make steroids (testis). Deficiency in this mRNA regulator may lead to more sluggish responses to ACTH and stress as well as abnormal cortisol output.

描述(由申请人提供)：肾上腺皮质中的皮质醇合成在应激反应、饮食控制和心血管调节中起着核心作用。下丘脑-垂体-肾上腺轴的这种控制异常在代谢综合征中起着重要作用，代谢综合征通常与2型糖尿病有关。ACTH对皮质醇合成的刺激始于线粒体细胞色素P450 11A1将胆固醇转化为孕烯醇酮。这一步骤的激活依赖于类固醇合成急性调节因子(STAR)的新合成及其被蛋白激酶A(PKA)的磷酸化。STAR缺乏症会导致高脂血症肾上腺功能不全。这项研究的重点是发现PKA和蛋白激酶C(PKC)以非常不同的方式刺激STAR的表达。我们将展示如何通过组蛋白脱乙酰酶和ERK激酶的基本贡献来清楚地区分这些过程。我们将描述核因素对这些过程的不同贡献，包括分化调节因子SF-1。这包括在转录过程中上下循环的依赖时间的修饰(磷酸化/去磷酸化和乙酰化/去乙酰化)。将有证据表明，PKA还可以增强PKC过程的后期，从而在STAR转录中产生强大的协同作用。STAR的转录后调控提供了PKA和PKC调控的另一个区别。一种新的调控因子，锌指蛋白TIS11b，针对3.5kb STAR mRNA延伸的3‘非翻译区的特定序列。TIS11b可被PKA迅速激活，但被PKC抑制。我们将在STAR 3.5kb mRNA末端识别特定的TIS11b识别位点，并表明这种相互作用可以促进STAR蛋白的翻译，同时增加mRNA的降解。我们将测试TIS11b是否由于包括SF-1在内的共同转录因子而与STAR共转录。我们将确定这些机制在ACTH刺激过程中是如何相互作用的，包括在原代肾上腺细胞系和活体肾上腺中。在STAR表达过程中，指定SF-1和TIS11b相互作用的启动子和mRNA序列从小鼠到人类基本上是保守的。我们将测试这些小鼠机制是否保留在人肾上腺H295细胞中。我们的研究表明，TIS11b与STAR的相互作用和延伸的STAR mRNA的优势在原代牛肾上腺细胞中是保守的，并对ACTH做出反应。这项工作将把几个实验室聚集在一起，初步了解PKA、SF-1和TIS11b(或与每个相关的因子)之间的相互作用，这可能发生在多种类固醇生成组织中。肾上腺皮质中的皮质醇合成在应激反应、饮食控制和心血管调节中起着核心作用。ACTH因应激而升高，通过促进胆固醇转化为孕烯醇酮来刺激皮质醇的合成。这一步依赖于类固醇合成急性调节剂(STAR)的新合成。这项拟议的研究涉及一种新的过程，即ACTH不仅刺激STAR的转录，还刺激一种名为TIS11b的蛋白质，TIS11b分别调节STAR蛋白的翻译和mRNA的降解。我们对控制STAR和TIS11b转录的调控过程进行了详细的分析，以了解它们潜在的协调。TIS11b可能加快了对应激的反应时间，同时也有助于当ACTH刺激被去除时STAR的去除。TIS11b调节在其他组织中也存在，这些组织产生类固醇(睾丸)。这种mRNA调节因子的缺失可能会导致对ACTH和应激的反应更加迟缓，以及皮质醇输出异常。